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CIGB-300, formerly known as P15-tat, is a proapoptotic peptide with established antiproliferative activity in vitro and antitumoral activity in vivo. This hypothesis-driven peptide was initially selected for its ability to impair the in vitro CK2-mediated phosphorylation in one of its substrates through direct binding to the conserved acidic phosphoaceptor domain. However, the actual in vivo target(s) on human cancer cells among the hundreds of CK2 substrates as well as the subsequent events that lead to apoptosis on tumor cells remains to be determined. In this work, we identified the multifunctional oncoprotein nucleophosmin/B23 as a major target for CIGB-300. In vivo, the CIGB-300–B23 interaction was shown by pull-down experiments and confirmed by the early in situ colocalization of both molecules in the cell nucleolus. Moreover, CIGB-300 inhibits the CK2-mediated phosphorylation of B23 in a dose-dependent fashion both in vitro and in vivo as shown using the recombinant GST fusion protein and the metabolic labeling approach, respectively. Such phosphorylation impairment was correlated with the ability of CIGB-300 to induce nucleolar disassembly as documented by the use of established markers for nucleolar structure. Finally, we showed that such a sequence of events leads to the rapid and massive onset of apoptosis both at the molecular and cellular levels. Collectively, these findings provide important clues by which the CIGB-300 peptide exerts its proapoptotic effect on tumor cells and highlights the suitability of the B23/CK2 pathway for cancer-targeted therapy. [Mol Cancer Ther 2009;8(5):OF1–8]

CK2 is a serine/threonine kinase that is overexpressed in breast cancer and its inhibition is associated to reduced tumor growth and disease progression. CIGB-300 is an antitumor peptide with a novel mechanism of action, since it binds to protein kinase CK2 catalytic subunit alpha and to CK2 substrates thus preventing the enzyme activity. Our aim was to evaluate the potential therapeutic benefits of CIGB-300 on breast cancer disease using experimental models with translational relevance. We demonstrated that CIGB-300 reduces breast cancer cell growth in MDA-MB-231, MCF-7 and F3II cells, exerting a pro-apoptotic action and cell cycle arrest. We also found that CIGB-300 decreased cell adhesion, migration and clonogenic capacity of malignant cells. Effect on experimental breast cancer lung metastasis was evaluated after surgical removal of primary F3II tumors or after tail vein injection of tumor cells, also we evaluated CIGB-300 effect on spontaneous lung metastasis in an orthotopic model. Systemic CIGB-300 treatment inhibited breast cancer colonization of the lung, reducing the size and number of metastatic lesions. The present preclinical study establishes for the first time the efficacy of CIGB-300 on breast cancer. These encouraging results suggest that CIGB-300 could be used for the management of breast cancer as an adjuvant therapy after surgery, limiting tumor metastatic spread and thus protecting the patient from distant recurrence.

Yerba Mate (Ilex paraguariensis St. Hill. Aquifoliaceae) is a native South American tree and has a large amount of bioactive compounds. Colorectal cancer (CRC) is one of the so-called westernized diseases and is the third most common cancer in both men and women. Efficient strategies for the treatment of CRC are extensively being explored including dietary intervention. The objective of our research was to evaluate the effects of Yerba Mate extract on cell proliferation, invasive capacity of tumor cells, and angiogenesis. For this, in vitro and in vivo experimentation was carried out using CRC models. The extract was generated by aqueous extraction and prepared according to traditional American procedure of preparing mate infusion. In vitro results showed that the Yerba Mate extract inhibits CT26 and COLO 205 cell proliferation with IC50 values of 0.25 and 0.46 mg/mL, respectively. We demonstrated by TUNEL assay that one of the mechanisms by which Yerba Mate extract decreases cell proliferation is by induction of apoptosis. In a murine syngeneic tumor model, oral administration of Yerba Mate extract in a dose of 1.6 g/kg/day significantly inhibited angiogenesis and tumor growth without affecting biological parameters or body weight. Our findings suggest that Yerba Mate may be a promising agent for the treatment of colon cancer and could be used as an herbal medicine or functional food ingredient. PRACTICAL APPLICATION: Considering the chemical composition and presence of phenolic compounds with their free-radical scavenging activities and bioactivities against colon cancer cells, Yerba Mate can be a promising candidate as healthy food sources in human nutrition, and also be considered a natural source of potential antitumor agents. Taking into account the economic importance of Yerba Mate in Argentina, this vegetable would have a greater commercial value as a functional food.

Osteosarcoma is still associated with limited response to standard-of-care therapy and alarmingly elevated mortality rates, especially in low- and middle-income countries. Despite multiple efforts to repurpose β-blocker propranolol in oncology, its potential application in osteosarcoma management remains largely unexplored. Considering the unsatisfied clinical needs of this aggressive disease, we evaluated the antitumoral activity of propranolol using different in vitro and in vivo osteosarcoma preclinical models, alone or in addition to chemotherapy. Propranolol significantly impaired cellular growth in β2-adrenergic receptor-expressing MG-63 and U-2OS cells, and was capable of blocking growth-stimulating effects triggered by catecholamines. siRNA-mediated ADRB2 knockdown in MG-63 cells was associated with decreased cell survival and a significant attenuation of PPN anti-osteosarcoma activity. Direct cytostatic effects of propranolol were independent of apoptosis induction and were associated with reduced mitosis, G0/G1 cell cycle arrest and a significant down-regulation of cell cycle regulator Cyclin D1. Moreover, colony formation, 3D spheroid growth, cell chemotaxis and capillary-like tube formation were drastically impaired after propranolol treatment. Interestingly, anti-migratory activity of β-blocker was associated with altered actin cytoskeleton dynamics. In vivo, propranolol treatment (10 mg/kg/day i.p.) reduced the early angiogenic response triggered by MG-63 cells in nude mice. Synergistic effects were observed in vitro after combining propranolol with chemotherapeutic agent cisplatin. Sustained administration of propranolol (10 mg/kg/day i.p., five days a week), alone and especially in addition to low-dose metronomic cisplatin (2 mg/kg/day i.p., three times a week), markedly reduced xenograft progression. After histological analysis, propranolol and cisplatin combination resulted in low tumor mitotic index and increased tumor necrosis. β-blockade using propranolol seems to be an achievable and cost-effective therapeutic approach to modulate osteosarcoma aggressiveness. Further translational studies of propranolol repurposing in osteosarcoma are warranted.

Nuclear transport and vesicle trafficking are key cellular functions involved in the pathogenesis of RNA viruses. Among other pleiotropic effects on virus-infected host cells, ivermectin (IVM) inhibits nuclear transport mechanisms mediated by importins and atorvastatin (ATV) affects actin cytoskeleton-dependent trafficking controlled by Rho GTPases signaling. In this work, we first analyzed the response to infection in nasopharyngeal swabs from SARS-CoV-2-positive and -negative patients by assessing the gene expression of the respective host cell drug targets importins and Rho GTPases. COVID-19 patients showed alterations in KPNA3, KPNA5, KPNA7, KPNB1, RHOA, and CDC42 expression compared with non-COVID-19 patients. An in vitro model of infection with Poly(I:C), a synthetic analog of viral double-stranded RNA, triggered NF-κB activation, an effect that was halted by IVM and ATV treatment. Importin and Rho GTPases gene expression was also impaired by these drugs. Furthermore, through confocal microscopy, we analyzed the effects of IVM and ATV on nuclear to cytoplasmic importin α distribution, alone or in combination. Results showed a significant inhibition of importin α nuclear accumulation under IVM and ATV treatments. These findings confirm transcriptional alterations in importins and Rho GTPases upon SARS-CoV-2 infection and point to IVM and ATV as valid drugs to impair nuclear localization of importin α when used at clinically-relevant concentrations.

Malignant gliomas are the most common primary central nervous system tumor in adults. Despite current therapeutics, these tumors are associated with poor prognosis and a median survival of 16 to 19 months. This highlights the need for innovative treatments for this incurable disease. Rac1 has long been associated with tumor progression and plays a key role in glioma’s infiltrative and invasive nature. The aim of this study is to evaluate the 1A-116 molecule, a Rac1 inhibitor, as targeted therapy for this aggressive disease. We found that targeting Rac1 inhibits cell proliferation and cell cycle progression using different in vitro human glioblastoma models. Additionally, we evaluated 1A-116 in vivo, showing a favorable toxicological profile. Using in silico tools, 1A-116 is also predicted to penetrate the blood–brain barrier and present a favorable metabolic fate. In line with these results, 1A-116 i.p daily treatment resulted in a dose-dependent antitumor effect in an orthotopic IDH-wt glioma model. Altogether, our study provides a strong potential for clinical translation of 1A-116 as a signal transduction-based precision therapy for glioma and also increases the evidence of Rac1 as a key molecular target.

Background: There are limited antiviral options for the treatment of patients with COVID-19. Ivermectin (IVM), a macrocyclic lactone with a wide anti-parasitary spectrum, has shown potent activity against SARSCoV-2 in vitro. This study aimed at assessing the antiviral effect of IVM on viral load of respiratory secretions and its relationship with drug concentrations in plasma. Methods: Proof-of-concept, pilot, randomized, controlled, outcome-assessor blinded trial to evaluate antiviral activity of high-dose IVM in 45 COVID-19 hospitalized patients randomized in a 2:1 ratio to standard of care plus oral IVM at 0¢6 mg/kg/day for 5 days versus standard of care in 4 hospitals in Argentina. Eligible patients were adults with RT-PCR confirmed SARS-CoV-2 infection within 5 days of symptoms onset. The primary endpoint was the difference in viral load in respiratory secretions between baseline and day-5, by quantitative RT-PCR. Concentrations of IVM in plasma were measured. Study registered at ClinicalTrials.gov: NCT04381884. Findings: 45 participants were recruited (30 to IVM and 15 controls) between May 18 and September 9, 2020. There was no difference in viral load reduction between groups but a significant difference was found in patients with higher median plasma IVM levels (72% IQR 59 77) versus untreated controls (42% IQR 31 73) (p = 0¢004). Mean ivermectin plasma concentration levels correlated with viral decay rate (r: 0¢47, p = 0¢02). Adverse events were similar between groups. No differences in clinical evolution at day-7 and day-30 between groups were observed. Interpretation: A concentration dependent antiviral activity of oral high-dose IVM was identified at a dosing regimen that was well tolerated. Large trials with clinical endpoints are necessary to determine the clinical utility of IVM in COVID-19. Fil: Krolewiecki, Alejandro Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Salta. Sede Regional Orán. Instituto de Investigación de Enfermedades Tropicales; Argentina Fil: Lifschitz, Adrian Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias. Departamento de Fisiopatología. Laboratorio de Farmacología; Argentina Fil: Moragas, Matías. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; Argentina Fil: Travacio, Marina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Analítica y Fisicoquímica. Cátedra de Química General e Inorgánica; Argentina Fil: Valentini, Ricardo. Centro de Educaciones Médicas e Investigación Clínica "Norberto Quirno"; Argentina Fil: Alonso, Daniel Fernando. Universidad Nacional de Quilmes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Solari, Rubén. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas "Dr. Francisco Javier Muñiz"; Argentina Fil: Tinelli, Marcelo Adrián. Laboratorio Elea/Phoenix; Argentina Fil: Cimino, Rubén Oscar. Universidad Nacional de Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Alvarez, Luis Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; Argentina Fil: Fleitas, Pedro Emanuel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Salta. Sede Regional Orán. Instituto de Investigación de Enfermedades Tropicales; Argentina Fil: Ceballos, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; Argentina Fil: Golemba, Marcelo Darío. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Fernández, Florencia. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; Argentina Fil: Fernández de Oliveira, Diego. Centro de Educaciones Médicas e Investigación Clínica "Norberto Quirno"; Argentina Fil: Astudillo, German. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas "Dr. Francisco Javier Muñiz"; Argentina Fil: Baeck, Inés. Centro de Educaciones Médicas e Investigación Clínica "Norberto Quirno"; Argentina Fil: Farina, Javier. Hospital Cuenca Alta; Argentina Fil: Cardama, Georgina Alexandra. Universidad Nacional de Quilmes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Mangano, Andrea María Mercedes. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Spitzer, Eduardo. Laboratorio Elea/phoenix; Argentina Fil: Gold, Silvia. Fundación Mundo Sano; Argentina Fil: Lanusse, Carlos Edmundo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; Argentina

Orthohantaviruses are emerging rodent-borne pathogens that cause Hantavirus Pulmonary Syndrome in humans. They have a wide range of rodent reservoir hosts and are transmitted to humans through aerosolized viral particles generated by the excretions of infected individuals. Since the first description of HPS in Argentina, new hantaviruses have been reported throughout the country, most of which are pathogenic to humans.We present here the first HPS case infected with Alto Paraguay virus reported in Argentina. Until now, Alto Paraguay virus was considered a non-pathogenic orthohantavirus since it was identified in a rodent, Hollochilus chacarius. In addition to this, with the goal of identifying potential hantavirus host species in the province of Santa Fe, we finally describe a novel orthohantavirus found in the native rodent Scapteromys aquaticus, which differed from other hantaviruses described in the country so far.Our findings implicate an epidemiological warning regarding these new orthohantaviruses circulating in Central Argentina as well as new rodent species that must be considered as hosts from now on.

Osteosarcoma is the most prevalent primary bone malignancy. Due to its high aggressiveness, novel treatment strategies are urgently required to improve survival of patients with osteosarcoma, especially those with advanced disease. Desmopressin (dDAVP) is a widely used blood-saving agent that has been repurposed as an adjuvant agent for cancer management due to its antiangiogenic and antimetastatic properties. dDAVP acts as a selective agonist of the vasopressin membrane receptor type 2 (AVPR2) present in the microvascular endothelium and in some cancer cells, including breast, lung, colorectal and neuroendocrine tumor cells. Despite the fact that dDAVP has demonstrated its antitumor efficacy in a wide variety of tumor types, exploration of its potential anti-osteosarcoma activity has, to the best of our knowledge, not yet been conducted. Therefore, the aim of the present study was to evaluate the preclinical antitumor activity of dDAVP in osteosarcoma. Human MG-63 and U-2 OS osteosarcoma cell lines were used to assess in vitro and in vivo therapeutic effects of dDAVP. At low micromolar concentrations, dDAVP reduced AVPR2-expressing MG-63 cell growth in a concentration-dependent manner. In contrast, dDAVP exhibited no direct cytostatic effect on AVPR2-negative U-2 OS cells. As it would be expected for canonical AVPR2-activation, dDAVP raised intracellular cAMP levels in osteosarcoma cells, and coincubation with phosphodiesterase-inhibitor rolipram indicated synergistic antiproliferative activity. Cytostatic effects were associated with increased apoptosis, reduced mitotic index and impairment of osteosarcoma cell chemotaxis, as evaluated by TUNEL-labeling, mitotic body count in DAPI-stained cultures and Transwell migration assays. Intravenous administration of dDAVP (12 µg/kg; three times per week) to athymic mice bearing rapidly growing MG-63 xenografts, was indicated to be capable of reducing tumor progression after a 4-week treatment. No major alterations in animal weight, biochemical or hematological parameters were associated with dDAVP treatment, confirming its good tolerability and safety. Finally, AVPR2 expression was detected by immunohistochemistry in 66% of all evaluated chemotherapy-naive human conventional osteosarcoma biopsies. Taking these findings into account, repurposed agent dDAVP may represent an interesting therapeutic tool for the management of osteosarcoma. Further preclinical exploration of dDAVP activity on orthotopic or metastatic osteosarcoma models are required.

Background Blueberries are among the fruits with the highest antioxidant activity and have been recognized by their health promoting properties. Aim In vitro study of the anti-proliferative effects of a blueberry extract on a panel of cancer cells from different origin. Materials and methods A blueberry extract was produced using ethanol as extracting solvent. The anti-proliferative activity of the extract was evaluated against seven tumor cell lines. The properties of blueberry extract to decrease cell adhesion and migration were also investigated. Results Blueberry extract showed a dose-dependent inhibitory effect on cell proliferation for all cell lines. Non-cytotoxic concentrations of the extract decreased cell adhesion in five of seven cell lines studied and inhibited the migration of MDA-MB-231 and PC-3 tumor cells. Conclusion This work provides additional evidence regarding the ability of blueberry extract to inhibit the growth and decrease cell adhesion and migration of different cancer cell lines in vitro.

Fil: Alonso, Daniel Fernando. Universidad Nacional de Quilmes; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina

Since its discovery, arginine vasopressin (AVP) was subjected to several modifications with the aim of obtaining novel derivatives with increased potency and selectivity for biomedical use. Desmopressin (dDAVP) is a first generation synthetic analog of AVP with hemostatic and antimetastatic activity. dDAVP acts as a selective agonist of the arginine vasopressin type 2 receptor (AVPR2) present in microvascular endothelium and cancer cells. Considering its selective effects on AVPR2-expressing malignant and vascular tissue, and interesting antitumor profile, dDAVP was used as a lead compound for the development of novel peptide analogs with enhanced anticancer efficacy. After conducting different structure-activity relationship studies to determine key aminoacidic positions for its antitumor activity against AVPR2-expressing malignant cells, dDAVP was rationally modified and a wide panel of synthetic analogs with different sequence and structural modifications was assessed. As a result of this structure-based drug derivatization novel AVP analog [V

Background: There are limited antiviral options for the treatment of patients with coronavirus disease 2019 (COVID-19) that have demonstrated clinical efficacy and none of them is an oral drug. Ivermectin (IVM), a macrocytic lactone with a wide anti-parasitary spectrum, has shown potent in vitro activity against SARS-CoV-2 in cell cultures. Methods: We completed a pilot, randomized, controlled, outcome-assessor blinded clinical trial with the goal of evaluating the antiviral activity of high dose IVM in COVID-19 patients. Eligible patients were adults (aged 18 to 69 years) with mild or moderate RT-PCR confirmed SARS-CoV-2 infection within 5 days of symptoms onset. 45 patients were randomized in a 2:1 ratio to standard of care plus oral IVM at 0·6 mg/kg/day for 5 days versus standard of care. The primary endpoint was viral load reduction in respiratory secretions at day-5. Viral load in respiratory secretions was measured through quantitative RT-PCR. Concentrations of IVM in plasma were measured on multiple treatment days. Findings: The trial run between May 18 and September 29, 2020 with 45 randomized patients (30 in the IVM group and 15 controls). There was no difference in viral load reduction between groups but a significant difference in reduction was found in patients with higher median plasma IVM levels (72% IQR 59 – 77) versus untreated controls (42% IQR 31 – 73) (p=0·004). The mean ivermectin plasma concentration levels also showed a positive correlation with viral decay rate (r:0·47, p=0·02). Adverse events were reported in 5 (33%) patients in the controls and 13 (43%) in the IVM treated group, without a relationship between IVM plasma levels and adverse events. Interpretation: A concentration dependent antiviral activity of oral high dose IVM was identified in this pilot trial at a dosing regimen that was well tolerated. Large trials with clinical endpoints are necessary to determine the clinical utility of IVM in COVID-19. Trial Registration: This trial is registered with ClinicalTrials.gov, NCT004381884. Funding Statement: This work was supported by grant IP-COVID-19-625 from Agencia Nacional de Promocion de la Investigacion, el Desarrollo Tecnologico y la Innovacion, Argentina and Laboratorio ELEA/Phoenix, Argentina. Declaration of Interests: AK reports grants from Laboratorio Elea/Phoenix. MAT, MDG and ES are employees of Laboratorios Elea/Phoenix. SG is a moember of the Board of Directors of Laboratorio Elea/Phoenix. All other authors declare no competing interests. Ethics Approval Statement: Ethical approval was obtained from the Institutional Independent Ethics Committees and from district and national regulatory agencies. All participating individuals provided written informed consent. The trial was done in accordance with the principles of the Declaration of Helsinki.

Aims: The influence of the COVID-19 pandemic on attendance to out-of-hospital cardiac arrest (OHCA) has only been described in city or regional settings. The impact of COVID-19 across an entire country with a high infection rate is yet to be explored. Methods: The study uses data from 8629 cases recorded in two time-series (2017/2018 and 2020) of the Spanish national registry. Data from a nonCOVID-19 period and the COVID-19 period (February 1st-April 30th 2020) were compared. During the COVID-19 period, data a further analysis comparing non-pandemic and pandemic weeks (defined according to the WHO declaration on March 11th, 2020) was conducted. The chi-squared analysis examined differences in OHCA attendance and other patient and resuscitation characteristics. Multivariate logistic regression examined survival likelihood to hospital admission and discharge. The multilevel analysis examined the differential effects of regional COVID-19 incidence on these same outcomes. Results: During the COVID-19 period, the incidence of resuscitation attempts declined and survival to hospital admission (OR = 1.72; 95%CI = 1.46-2.04; p < 0.001) and discharge (OR = 1.38; 95%CI = 1.07-1.78; p = 0.013) fell compared to the non-COVID period. This pattern was also observed when comparing non-pandemic weeks and pandemic weeks. COVID-19 incidence impinged significantly upon outcomes regardless of regional variation, with low, medium, and high incidence regions equally affected. Conclusions: The pandemic, irrespective of its incidence, seems to have particularly impeded the pre-hospital phase of OHCA care. Present findings call for the need to adapt out-of-hospital care for periods of serious infection risk. Study registration number: ISRCTN10437835.

Since its discovery, arginine vasopressin (AVP) was subjected to several modifications with the aim of obtaining novel derivatives with increased potency and selectivity for biomedical use. Desmopressin (dDAVP) is a first generation synthetic analog of AVP with hemostatic and antimetastatic activity. dDAVP acts as a selective agonist of the arginine vasopressin type 2 receptor (AVPR2) present in microvascular endothelium and cancer cells. Considering its selective effects on AVPR2-expressing malignant and vascular tissue, and interesting antitumor profile, dDAVP was used as a lead compound for the development of novel peptide analogs with enhanced anticancer efficacy. After conducting different structure-activity relationship studies to determine key aminoacidic positions for its antitumor activity against AVPR2-expressing malignant cells, dDAVP was rationally modified and a wide panel of synthetic analogs with different sequence and structural modifications was assessed. As a result of this structure-based drug derivatization novel AVP analog [V4Q5]dDAVP (1-deamino-4-valine-5-glutamine-8- d -arginine vasopressin) was selected as the most active candidate and further developed. [V4Q5]dDAVP was evaluated in highly aggressive and metastatic cancer preclinical models deploying enhanced cytostatic, antimetastatic and angiostatic effects in comparison to parental peptide dDAVP. In addition, novel compound demonstrated good tolerability as evaluated in several toxicological studies, and cooperative therapeutic effects after combination with standard-of-care chemotherapy. In summary, due to its ability to inhibit growth and tumor-associated angiogenesis, as well as impairing progression of metastatic disease, AVP analogs such as novel [V4Q5]dDAVP are promising compounds for further development as coadjuvant agents for the management of advance or recurrent cancers.

Antitumor strategies based on positive modulation of the immune system currently represent therapeutic options with prominent acceptance for cancer patients’ treatment due to its selectivity and higher tolerance compared to chemotherapy. Racotumomab is an anti-idiotype (anti-Id) monoclonal antibody (mAb) directed to NeuGc-containing gangliosides such as NeuGcGM3, a widely reported tumor-specific neoantigen in many human cancers. Racotumomab has been approved in Latin American countries as an active immunotherapy for advanced non-small cell lung cancer (NSCLC) treatment. In this work, we evaluated the induction of Ab-dependent cell-mediated cytotoxicity (ADCC) in NSCLC patients included in a phase III clinical trial, in response to vaccination with racotumomab. The development of anti-NeuGcGM3 antibodies (Abs) in serum samples of immunized patients was first evaluated using the NeuGcGM3-expressing X63 cells, showing that racotumomab vaccination developed antigen-specific Abs that are able to recognize NeuGcGM3 expressed in tumor cell membranes. ADCC response against NeuGcGM3-expressing X63 (target) was observed in racotumomab-treated- but not in control group patients. When target cells were depleted of gangliosides by treatment with a glucosylceramide synthase inhibitor, we observed a significant reduction of the ADCC activity developed by sera from racotumomab-vaccinated patients, suggesting a target-specific response. Our data demonstrate that anti-NeuGcGM3 Abs induced by racotumomab vaccination are able to mediate an antigen-specific ADCC response against tumor cells in NSCLC patients. Fil: Segatori, Valeria Inés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Cuello, Héctor Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Gulino, Cynthia Antonella. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Albertó, Marina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Venier, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Inmunología, Genética y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Inmunología, Genética y Metabolismo; Argentina Fil: Guthmann, Marcelo D.. Elea Laboratories; Argentina Fil: Demarco, Ignacio A.. Elea Laboratories; Argentina Fil: Alonso, Daniel Fernando. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Gabri, Mariano Rolando. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Breast cancer is the first cause of death from female cancer. After treatments against the primary tumor, a few cells can prevail in a dormant state for a long period, becoming minimal residual disease. These cells can resume growth and establish as metastasis, which are responsible for 90% of deaths from cancer. Patients with breast cancer diagnosed at early stage with small tumours have a 25-30% chance of recurrence after 10-15 years after treatment. These new growth often entails chemo and radio resistance and there is not response to conventional treatment. For all these reasons, there is a clear need for the development of novel therapies against these cells in a dormant state. The main limitation on the study of these dormant cells is the lack of relevant in vitro an in vivo models. In this work, we isolated and characterized two novel cell lines F3II-TP and F3II-NM. F3II-TP represents tumours with high proliferation rate whereas F3II-NM represents a dormant cell phenotype. The comparison between these cell lines is expected to yield new molecular targets for the design of new drugs that point dormant cells. The study began with the isolation and establishment of new tumour cell lines. After inoculation of the F3II murine mammary carcinoma cell line, we established cell populations in vitro, one from the primary tumour and another from a spontaneous metastatic nodule, F3II TP and F3II NM cell lines respectively. First, we analysed the expression of EMT markers such as E-cadherin, N-cadherin, Vimentin, Pan-Cytoqueratin and β-catenin by immunofluorescence. In in vitro assays, F3II NM presented major doubling time, major adhesion capacity and lower clonogenic potential. In addition, the expression of the dormancy related genes such as NR2F1 and BHLHE41 was analysed by qPCR, and we found that F3II-NM showed higher levels of transcript than F3II-TP. In addition, F3II NM showed lower chemo sensibility to cisplatin and in an orthotopic model of BALB/c mice, presented a longer latency time and lower tumour growth rate in comparison to F3II-TP. Taking all these together, F3II NM present a dormant phenotype and F3II TP a proliferative one. Finally, analysis and comparison of the cell lines using LFQ-Mass spectrometry revealed 256 differentially expressed proteins between the lines studied. Overexpressed genes of survival paths were identified in F3II-NM, such as DDX42, COX-2, ATGB4 involved in the inhibition of apoptosis, promotion of tumour recurrence via SOX-2 and therapy resistance, respectively. To sum up, we established a new interesting dormant tumour cell model, F3II NM that could help to a better understanding of the behaviour and survival of dormant cells. Moreover, we identified interesting protein targets that encourage the possibility of design new drugs that point and eliminate dormant cells Citation Format: Johanna E. Sidabra, Carla S. Capobianco, Maria F. Gottardo, Daniel F. Alonso, Hernan G. Farina. Isolation and characterization of novel murine mammary cell line with dormant phenotype and identification of new potential targets by mass spectrometry [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2649.

Introduction. Osteosarcoma (OS) is the most common malignant primary bone tumor in children and young adults, with alarmingly elevated mortality rates, especially in developing countries. OS patients bear highly invasive and vascularized tumors, with limited response to standard of care (SoC) therapies, and are in urgent need of novel therapeutic strategies. Propranolol (PPN) is a non-selective β-adrenergic receptor (β-AR) antagonist originally used in the treatment of diverse heart diseases. On the other hand, desmopressin (dDAVP) is a hemostatic drug that acts as a selective agonist for the vasopressin type-2 receptor (AVPR2) present in blood microvessels and several tumor types. Given that β-ARs and AVPR2 signalling regulates many cellular processes involved in the initiation and progression of cancer, multiple efforts have been made to repurpose PPN and dDAVP in indications such as breast and colorectal cancer, melanoma and angiosarcoma, among others. Considering the unsatisfied clinical needs of OS, the objective of this work was to evaluate the in vitro/in vivo antitumoral activity of PPN and dDAVP on highly aggressive preclinical models of OS. Materials and methods. The human OS cell lines MG-63 and U2-OS were used for in vitro or in vivo experiments. Target expression was assessed by qPCR and immunohistochemistry. Sensitivity to PPN or dDAVP was evaluated by in vitro 72 h proliferation, 7 d clonogenic growth, 3D spheroid formation, transwell chemotaxis assays and MG-63 xenograft progression in nude mice. In addition, PPN was evaluated as monotherapy or in combination with SoC chemotherapy. Results. PPN (10-100 µM) and dDAVP (0.1-10 µM) drastically reduced clonogenic and 3D growth, migration, mitotic index and proliferation of β-AR and AVPR2-expressing OS cells (p Conclusions. Taking into account PPN and dDAVP robust antitumoral effects, β-ARs antagonization or agonist activation of AVPR2 are achievable and interesting therapeutic approaches to modulate OS tumor aggressiveness. Both agents could be proposed as coadyuvant agents for treating OS, not only in combination with chemotherapy but also administered during the perioperative setting. Citation Format: Luisina Solerno, Natasha Sobol, Rocío Rodriguez, Marina Pifano, Giselle Ripoll, Hernan Farina, Liliana Vasquez, Daniel F. Alonso, Juan Garona. Drug repurposing of β-blocker propranolol and hemostatic compound desmopressin in osteosarcoma: Preclinical antitumor activity on 2D and 3D cell growth, chemotaxis and xenograft progression [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3062.

The p38 pathway can be activated by three different MAP kinase kinases: MKK3, MKK4 and MKK6, each one activated by different stimuli, like DNA damage, oxidative stress, proinflammatory cytokines or growth factors. In consequence, the responses mediated by this kinase are also significantly diverse. Its participation in such different processes makes it reasonable for the role of p38 in cancer to be a topic of current debate. Several authors reported a pro-tumorigenic role of p38, through the stimulation of tumor progression, epidermal to mesenchymal transition and migration and chemotherapy resistance, as a consequence of the transduction of pro-survival signals. Due to the above mentioned, the combination of p38 inhibitors and chemotherapy is frequently proposed as an interesting clinical approach for cancer treatment. In contrast, several reports underline the importance of p38 suppression of tumor initiation, metastasis inhibition through dormancy maintenance, and also a decisive role in the action mechanism of antitumor treatments under evaluation. Specifically, an important amount of evidence point p38 as a key apoptosis mediator in cancer cells, as a response to treatment with anticancer drugs included in different clinical and preclinical protocols. Previously we studied the effect of p38 inhibition in a mouse mammary carcinoma model named F3II. We described that in vitro inhibition of p38 provokes an increased in cell adhesion, cell spreading, proliferation in 3D cultures, ERK phosphorylation and Integrin α5 expression. In vivo inhibition also resulted in shortened latency times and increased tumor growth rates. In this work, we studied the effect of p38 inhibition in the development of recurrences after tumor surgery. When SB203580 inhibitor was administered after surgery, mice developed larger recurrences. Apoptotic cells in histological samples were detected by TUNEL analysis, showing that SB203580 treatment decreased the number of apoptotic cells in tumor recurrences. In addition, mitotic cell count in recurrence tissue showed that SB203580 treatment increased the mitotic index in the tumors. In conclusion, in this work we demonstrated that in F3II cell line, p38 inhibition promotes tumor recurrence development after surgery, mainly blocking the apoptotic response, and promoting cell duplication. Results presented in this work position p38 as a tumor suppressor kinase. The evidence presented here highlight the possible risk of the administration of a p38 inhibitor to oncological patients that may present newly disseminated cells, or a residual tumor mass that remains after treatment. From our perspective, candidates to be treated with new p38 inhibitors should be carefully selected according to the tumor type and the stage of the disease, since the response might be extremely variable between the different conditions. Citation Format: Carla S. Capobianco, Maria F. Gottardo, Johanna E. Sidabra, Julio A. Aguirre Ghiso, Daniel F. Alonso, Hernan G. Farina. p38 kinase acts as a negative regulator of recurrence after surgery in a mammary carcinoma model, through apoptosis induction and proliferation inhibition [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5983.

Yerba Mate (Ilex Paraguariensis) belongs to the Aquifoliaceae family and is a native plant of South America. This plant are enriched in bioactive compounds with biological activities. This study investigated the antitumor activity of Yerba Mate extract (YM) using in vitro and in vivo colon and breast cancer models. YM was generated by aqueous extraction and standardized to total phenolics content, antioxidant activity and Chlorogenic acid content. The HPLC analysis of the YM allowed us to quantify the main polyphenols: Chlorogenic acid (66.3 ± 0.05 mg/g dry sample), Rutin (6.783 ± 0.05 mg/g dry sample), Gallic acid (6.665 ± 0.321 mg/g dry sample), Caffeic acid (0.533 ± 0.04 mg/g dry sample) and Quercetin (0.229 ± 0.02 mg/g dry sample). To investigate the antitumoral activity of YM, we first evaluated its effect on cell proliferation of colon (CT26 and COLO205) and breast (MDA-MB 231, MCF7, F3II and 4T1) cancer cell lines. YM reduced tumor cell viability and induced apoptosis. In addition, YM showed negative modulatory effect on cell adhesion and migration of tumor cells and reduced their invasiveness capacity. The use of herbal products requires previous toxicity studies to identify the dose ranges that are safe for subsequent studies. Acute toxicity was evaluated in rats and chronic toxicity test was conducted in rabbits. Animals exposed showed no statistical changes in weight gain. Clinical examination and macroscopic analysis did not show any changes that indicate toxicity. We found a YM LD50 value above 5000 mg/kg. The effect of YM on tumor progression was also studied in vivo using different syngeneic tumor models. Animals received YM by oral administration in a dose of 1.6 g/kg/day before and after tumor cell inoculation. Orthotopic and heterotopic breast cancer models in BALB/c mice was performed. In the heterotopic F3II model the treatment with YM significantly reduced tumor volumes when compared with control group. In addition, the consumption of YM significantly increased the survival of animals in both models. We also studied the inhibition of spontaneous metastatic activity by YM. Diet with YM resulted in a reduced number of lung metastases compared to control in both models. On the other hand, in the heterothopic colorectal cancer model we observed that oral administration of YM reduced angiogenesis, delayed tumor onset and showed a reduction of tumor volume. The effects of the combination of YM extract with 5-fluorouracil (5-FU) was also evaluated in mice. The results suggest that this combination increased susceptibility of the colon cancer cells to the cytotoxicity of 5-Fu. In conclusion, our findings suggest that YM may be a promising agent for the treatment of breast and colon cancer in chemoprevention schemes or in combinatory schedules with standard-of-care therapeutics. Citation Format: Rocío S. García Lázaro, Humberto Lamdan, Norailys Lorenzo Perez, Lorena G. Caligiuri, Andrea L. Berengeno, Hugo H. Ortega, Daniel F. Alonso, Hernan G. Farina. Preclinical evidences of antitumoral properties of a Yerba mate extract on breast and colon cancer models [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3455.

Aim: To develop and characterize the antitumor activity of poly(D,L-lactic-co-glycolic acid) nanoparticles loaded with hemostatic and anticancer drug desmopressin (dDAVP). Materials & methods: After full physicochemical characterization, anticancer activity of dDAVP-loaded poly(D,L-lactic-co-glycolic acid) nanoparticles (NPdDAVP) was evaluated in vitro and in vivo on a highly aggressive breast cancer model. Results: After efficiently loading desmopressin in poly(D,L-lactic-co-glycolic acid) matrix, NPdDAVP exhibited suitable physicochemical characteristics for biomedical applications. NPdDAVP displayed a potent cytostatic effect in vitro, inhibiting tumor cell proliferation and colony forming ability. Moreover, intravenous treatment using nanoparticulated-dDAVP inhibited tumor progression and prolonged survival in animals bearing rapidly-growing mammary tumors. Conclusion: Within the framework of promising dDAVP repurposing studies, these findings support further preclinical development of the NPdDAVP for the management of highly aggressive cancer. Fil: Chevalier, Merari. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Garona, Juan. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Sobol, Natasha Tatiana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Farina, Hernán Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Alonso, Daniel Fernando. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina

Fil: Garona, Juan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Sobol, Natasha Tatiana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Alonso, Daniel Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina

Purpose Control of metastatic spread of colorectal cancer (CRC) remains as a major therapeutic challenge. [V 4 Q 5 ]dDAVP is a vasopressin peptide analog with previously reported anticancer activity against carcinoma tumors. By acting as a selective agonist of arginine vasopressin type 2 membrane receptor (AVPR2) present in endothelial and tumor cells, [V 4 Q 5 ]dDAVP is able to impair tumor aggressiveness and distant spread. Our aim was to evaluate the potential therapeutic benefits of [V 4 Q 5 ]dDAVP on highly aggressive CRC disease using experimental models with translational relevance. Materials and Methods Murine CT-26 and human Colo-205 AVPR2-expressing CRC cell lines were used to test the preclinical efficacy of [V 4 Q 5 ]dDAVP, both in vitro and in vivo. Results In syngeneic mice surgically implanted with CT-26 cells in the spleen, sustained intravenous treatment with [V 4 Q 5 ]dDAVP (0.3 jg/kg) dramatically impaired metastatic progression to liver without overt signs of toxicity, and also reduced experimental lung colonization. The compound inhibited in vivo angiogenesis driven by Colo-205 cells in athymic mice, as well as in vitro endothelial cell migration and capillary tube formation. [V 4 Q 5 ]dDAVP exerted AVPR2-dependent cytostatic activity in vitro (IC50 1.08 |jM) and addition to 5-fluorouracil resulted in synergistic antiproliferative effects both in CT-26 and Colo-205 cells. Conclusion The present preclinical study establishes for the first time the efficacy of [V 4 Q 5 ]dDAVP on CRC. These encouraging results suggest that the novel second generation vasopressin analog could be used for the management of aggressive CRC as an adjuvant agent during surgery or to complement standard chemotherapy, limiting tumor angiogenesis and metastasis and thus protecting the patient from CRC recurrence. Fil: Garona, Juan. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Sobol, Natasha Tatiana. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Pifano, Marina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Segatori, Valeria Inés. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Gomez, Daniel Eduardo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Ripoll, Giselle Vanina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Alonso, Daniel Fernando. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Aim: Development of compounds with therapeutic application requires the interaction of different disciplines. Several tumors express vasopressin (AVP; arginine vasopressin) receptors with contrasting effects depending on receptor subtype. Desmopressin (dDAVP) is an AVP-selective analog with antiproliferative properties. In this work, an evolutionary approach and a rational strategy were applied in order to design novel AVP analogs. Results: We designed two novel analogs; dDInotocin (dDINT, insect analog), and [V4Q5]dDAVP, and demonstrated the importance of the dDAVP conformational loop for its antiproliferative activity. [V4Q5] dDAVP showed major cytostatic effect on lung cancer cells than dDAVP and its cytostatic effect was abolished by V2R blockade. Conclusion: Combination of these strategies could provide the basis for future studies for the development of improved compounds with potential therapeutic applications. Fil: Pifano, Marina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Garona, Juan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Sobol, Natasha Tatiana. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Alberto, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Alonso, Daniel Fernando. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Ripoll, Giselle Vanina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Neuroblastoma (NB) is the most common pediatric malignancy diagnosed before the first birthday in which MYCN oncogene amplification is associated with poor prognosis. Although aberrant glycosylation is an important actor in cell biology, little is known about its role in pediatric cancers such as NB. In this work we characterized the glycophenotype and the enzyme expression involved in glycans biosynthesis in five established human NB cell lines and in patient-derived primary tumors with different MYCN status. Our results show a high expression of Lewis glycan family both in MYCN-amplified cell lines and patient samples. Additionally, we report that MYCN-amplified cells overexpressed Core 2-initiating glycosyltransferase C2GNT1 in association with specific ST3Gals and FUTs, and showed increased binding to E- and P- selectins. Silencing of C2GNT1 expression in NB cells diminished expression of Lewis glycans, decreased the E- and P-selectin binding, and reduced cell adhesion, migration and proliferation in vitro. Treatment of MYCN-non-amplified cells with Trichostatin A (TSA), an histone deacetylase inhibitor, increased the expression of Lewis glycans and the enzymes involved in their biosynthesis. Our results demonstrate that MYCN-amplified NB cells overexpress Lewis family glycans, which belong to the Core 2 O-glycans group. Their expression plays a key role in the malignant behaviour of the NB cells and it is modulated by epigenetic mechanisms.

Rac1 GTPase signaling pathway has a critical role in the regulation of a plethora of cellular functions governing cancer cell behavior. Recently, it has been shown a critical role of Rac1 in the emergence of resistance mechanisms to cancer therapy. This review describes the current knowledge regarding Rac1 pathway deregulation and its association with chemoresistance, radioresistance, resistance to targeted therapies and immune evasion. This supports the idea that interfering Rac1 signaling pathway could be an interesting approach to tackle cancer resistance. Fil: Cardama, Georgina Alexandra. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Alonso, Daniel Fernando. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: González, Nazareno. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Maggio, Julian. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Gomez, D.E.. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Rolfo, C.. Universiteit Antwerp; Bélgica Fil: Lorenzano Menna, Pablo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Background Pediatric neuroectodermal malignancies express N-glycolylated gangliosides including N-glycolyl GM3 (NeuGcGM3) as targets for immunotherapy. Procedure We evaluated the toxicity and maximum tolerated dose and immunological response of racotumomab, an anti-idiotype vaccine targeting NeuGcGM3 through a Phase I study enrolling children with relapsed or resistant tumors expressing NeuGcGM3. Materials and methods Drug dose was escalated to three levels (0.15–0.25–0.4 mg) of racotumomab administered intradermally. Each drug level included three patients receiving a total of three doses, every 14 days. A confirmation cohort was added to the highest dose level. Antibody response was assessed upon study entry and at 4-week intervals for at least three immunological determinations for each patient. Results Fourteen patients were enrolled (10 with neuroblastoma, one with retinoblastoma, one with Wilms' tumor, and two with brainstem glioma). Three patients completed the three drug levels and three were enrolled in the confirmation cohort. One patient died of tumor progression before completing the three applications. Racotumomab was well tolerated. The only side effect observed was grade 1–2 toxicity at the injection site. Racotumomab elicited an IgM and/or IgG antibody response directed against NGcGM3 in nine patients and IgM against racotumomab in 11 of 13 evaluable patients. The maximum tolerated dose was not reached and no dose-limiting toxicity was seen. Conclusions Racotumomab vaccination has a favorable toxicity profile up to a dose of 0.4 mg, and most patients elicited an immune response. Its activity as immunotherapy for neuroectodermal malignancies will be tested in further clinical trials. Pediatr Blood Cancer © 2015 Wiley Periodicals, Inc.

Background: dDAVP is a well known peptide analog of the antidiuretic hormone vasopressin, that has been used to prevent bleeding during surgical procedures in patients with hemostatic disorders. It induces a rapid increase of hemostatic mediators by stimulating their release from microvascular endothelial cells. In preclinical studies, dDAVP inhibited lymph node and early blood-borne metastasis from aggressive mouse mammary tumors. Besides, perioperative administration of dDAVP significantly prolonged disease-free and overall survival in a veterinary clinical trial enrolling dogs with locally advanced mammary cancer. The compound is a selective agonist of V2 vasopressin receptors present on both endothelial and breast cancer cells. Recent evidence indicated that dDAVP promotes tumor-mediated production of angiostatin and also activates endothelial release of von Willebrand factor (vWF), which may cause apoptosis of micrometastatic cells. Considering its hemostatic and antimetastatic properties, a phase II dose-escalation trial was performed in patients with breast cancer, administering a lyophilized formulation of dDAVP by IV infusion in saline, before and after surgical resection of primary tumor. Methods: Eligibility included otherwise healthy female patients between 18 and 65 years of age, histological/cytological diagnosis of breast carcinoma (Stage 0, I, II), and mastectomy or lumpectomy with sentinel node biopsy, either requiring or not further axillary dissection. dDAVP was administered in two IV infusions, the first 30-60 minutes before surgery and the second 24 hours later. Five groups of at least 4 patients each received increasing total dDAVP doses of 0.5, 1.0, 1.25, 1.5 and 2.0 μg/kg. Primary endopoints were safety and tolerability in breast cancer patients undergoing surgery as first treatment, as well as selection of the best dose for clinical use. Secondary endpoints included surgical bleeding, plasma levels of vWF, and circulating tumor cells (CTC) as measured by quantitative PCR detection of cytokeratin 19 (CK-19) mRNA in whole blood. Results: The trial accrued 21 patients from April 2012 to February 2014. Adverse events were reversible and observed from the third dose level (1.25 μg/kg), including nausea, hot flushing, skin rash, dyspnea and palpitations. Reactions were adequately managed by slowing the infusion rate of dDAVP (over 30 minutes). A reduced intraoperative bleeding of up to 50% was noted with increasing doses of dDAVP. Both vWF antigen and activity showed a rise after each dDAVP infusion, and maximum plasma levels were obtained at the higher dose level of 2 μg/kg. Interestingly, a preliminary analysis indicated a drop in CTC counts 24-48 hours after dDAVP treatment in patients with detectable CK-19 mRNA preoperative levels. Conclusions: At the highest dose level evaluated (2 μg/kg) perioperative dDAVP appeared safe when administered in two slow IV infusions of 1 μg/kg, before and after the surgical procedure. The available data suggest that treatment is associated with reduction of intraoperative bleeding, higher circulating vWF levels and postoperative drop in CTC counts. Final results will be available at the time of the meeting. Clinical trial number: NCT01606072. Citation Format: Ruth S Weinberg, Marcelo O Grecco, Gimena S Ferro, Debora Seigelshifer, Nancy V Perroni, Francisco J Terrier, Analia Sanchez Luceros, Enzo Domenichini, Marcelo D Guthmann, Daniela Di Leo, Eduardo Spitzer, Graciela N Ciccia, Ana V Torbidoni, Juan Garona, Marina Pifano, Giselle V Ripoll, Roberto E Gomez, Daniel F Alonso. Perioperative administration of desmopressin (dDAVP) in breast cancer patients: A phase II dose-escalation study [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-11-07.

Objectives: Casein kinase 2 (CK2) is overexpressed in several types of cancer. It has more than 300 substrates mainly involved in DNA reparation and replication, chromatin remodeling and cellular growth. In recent years CK2 became an interesting target for anticancer drug development. CIGB-300 is a peptidic inhibitor of CK2 activity, designed to bind to the phospho-acceptor domain of CK2 substrates, impairing the correct phosphorylation by the enzyme. The aim of this work was to explore the antitumor effects of this inhibitor in preclinical lung cancer models. Materials and methods: Human H125 and murine 3LL Lewis lung carcinoma cell lines were used to evaluate the effect of CIGB-300 treatment in vitro. For this purpose, adhesion, migration and invasion capabilities of cancer cells were tested. Proteolytic activity of tumor cell-secreted uPA and MMP after CIGB-300 incubation was also analyzed. In vivo anticancer efficacy of the peptide was evaluated using experimental and spontaneous lung colonization assays in C57BL/6 mice. Finally, in order to test the effect of CIGB-300 on tumor cell-induced angiogenesis, a modified Matrigel plug assay was conducted. Results and conclusion: We demonstrate that treatment with low micromolar concentrations of CIGB-300 caused a drastic reduction of adhesion, migration and invasion of lung cancer cells. Reduced invasiveness after CIGB-300 incubation was associated with decreased proteolytic activity of tumor cell-conditioned medium. In vivo, intravenous administration of CIGB-300 (10 mg/kg) markly decreased lung colonization and metastasis development of 3LL cells. Interestingly, after 5 days of systemic treatment with CIGB-300, tumor cell-driven neovascularization was significantly reduced in comparison to control group. Altogether our data suggest an important role of CK2 in lung tumor development, suggesting a potential use of CIGB-300 as a novel therapeutic agent against lung cancer. Fil: Benavent Acero, Fernando Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Capobianco, Carla Sabrina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Garona, Juan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Cirigliano, Stéfano Martín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología; Argentina Fil: Perera, Yasser. Centro de Ingeniería Genética y Biotecnología; Cuba Fil: Urtreger, Alejandro Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; Argentina Fil: Perea, Silvio E.. Centro de Ingeniería Genética y Biotecnología; Cuba Fil: Alonso, Daniel Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Farina, Hernán Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina

Tamoxifen is a standard endocrine therapy for estrogen receptor positive breast cancer patients. Despite its success,development of resistance mechanisms is still a serious clinical problem. Deregulation of survival signalingpathways play a key role in tamoxifen resistance, being upregulation of Rac1-PAK1 signaling pathway one of themost important. Here, we report the development of the breast cancer cell model MCF7::C1199 having Rac1 enhancedactivity with the aim of evaluating the role of Rac1 in acquired endocrine resistance. These cells not onlyshowed distinctive features of Rac1-regulated process as increased migration and proliferation rates, but alsoshowed that upregulation of Rac1 activity triggered a hormonal-independent and tamoxifen resistant phenotype.We also demonstrated that PAK1 activity increases in response to Tamoxifen, increasing phosphorylationlevels of estrogen receptor at Ser305, a key phosphorylation site involved in tamoxifen resistance. Finally, weevaluated the effect of 1A-116, a specific Rac1 inhibitor developed by our group, in tamoxifen-resistant cells.1A-116 effectively restored tamoxifen anti-proliferative effects, switched off PAK1 activity and decreasedestrogen receptor phospho-Ser305 levels. Since combination schemes of novel targeted agents with endocrinetherapy could be potential new strategies to restore tamoxifen sensibility, these results show that inhibition ofRac1-PAK1 signaling pathway may provides benefits to revert resistance mechanisms in endocrine therapies. Fil: Gonzalez, N.. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Cardama, Georgina Alexandra. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Comin, Maria Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Industrial; Argentina Fil: Segatori, Valeria Inés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Pifano, Marina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Alonso, Daniel Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Gomez, D. E.. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Lorenzano Menna, Pablo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Background: Desmopressin (dDAVP), a synthetic nonapeptide derivative of arginine vasopressin, is a safe hemostatic compound that acts as a selective agonist for the vasopressin V2 membrane receptor (V2R). This receptor is expressed in endothelium and also in some tumor cells. V2R stimulation is associated with increased levels of cyclic AMP and cyclic AMP-dependent protein kinase activation. We previously reported that dDAVP can inhibit progression of residual metastatic cells in preclinical models. Among other mechanisms, the compound induces an agonist effect on V2R present in tumor cells. This nonapeptide was substituted in positions 4 and 5 searching for compounds with improved biological activity. Such positions belong to the conformational peptide loop which has a key role in ligand-receptor interaction. After an extensive in vitro and in vivo characterization, novel peptide compound [4-valine 5-glutamine] dDAVP ([V4Q5]dDAVP) exerted a remarkable and improved antitumor effect in comparison to parental peptide dDAVP. [V4Q5]dDAVP inhibited tumor growth in both syngeneic F3II and xenogeneic MDA-MB-231 breast cancer models, modulating tumor aggressiveness and vasculature. In this study, to further understand direct cytostatic action of this novel vasopressin analog on tumor cells, we assessed the effect of [V4Q5]dDAVP on clonogenic and three dimensional growth of V2R-expressing human breast carcinoma cell lines. Methods and results: We used MCF7 and triple negative MDA-MB-231 human breast cancer cell lines to conduct the experiments. Vasopressin V2 membrane receptor expression in tumor cell lines was assessed by RT-PCR and immunofluorescence. We first examined peptide ability to modify in vitro low density cell growth by the clonogenic growth assay. Incubation with [V4Q5]dDAVP (100-1500 nM) during one week significantly reduced the number of tumor cell colonies showing a concentration dependant manner and an IC50 value of 1135 nM. To assess the effect of novel analog on three dimensional growth of cancer cells we used two different assays. The first one evaluates the ability of basement membrane extract (BME)-embedded single cells to proliferate and form spheroids. The second assay evaluates growth of single fully established spheroids (Approx. 300 mm diameter) transplanted individually on a non-adherent surface. [V4Q5]dDAVP, at a concentration of 1000 nM, was able to significantly reduce the number of BME-embedded spheroids formed from single cells after 14 days of treatment. In a similar manner, incubation of established and isolated spheroids with [V4Q5]dDAVP using the same concentration for 9 days, caused a decrease in multicellular spheroids final diameter. Cellular metabolic activity analysis by the MTS assay showed no significant differences between treated and control groups. Conclusions: We report for the first time the inhibitory effect of [V4Q5]dDAVP on colony and spheroid formation and growth of human breast carcinoma cells. Our results using three dimensional models suggest that V2R stimulation in cancer cells may affect early stages of microtumor establishment. Further analysis of involved signaling pathways in treated 3D cultures is needed. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-09-15.

Desmopressin (DDAVP), a synthetic peptide analog of vasopressin, is a safe antidiuretic and hemostatic compound that acts as a selective agonist for the vasopressin V2 membrane receptor. It is known that DDAVP can inhibit progression of residual metastatic cells and also improves chemotherapy effects in preclinical breast cancer models. Here, we explored the effects of DDAVP on tumor angiogenesis using the aggressive F3II mammary carcinoma in syngeneic Balb/c mice. Intravenous administration of the compound (2 μg/kg) markedly decreased vascularization of growing subcutaneous tumors, as well as inhibited the early angiogenic response around intradermal inoculation sites. In vitro studies confirmed the presence of vasopressin V2 receptors on F3II cells and a modest antiproliferative activity of DDAVP. Interestingly, conditioned media from F3II monolayers exposed to low doses of DDAVP (100 nM) significantly increased angiostatin formation in the presence of purified plasminogen. Such increase was associated with an enhancement of tumor-secreted urokinase-type plasminogen activator, suggesting the proteolytic conversion of plasminogen to angiostatin in vitro. Similar results were observed with the MCF-7 human breast carcinoma, a cell line known to express the vasopressin V2 receptor. No direct effects of DDAVP (100 nM–1 μM) were found on capillary-like tube formation by human microvascular cells HMVEC. Our studies showed that DDAVP induces anti-angiogenic effects that may be associated with the generation of angiostatin by tumor cells. Further preclinical studies with DDAVP and other vasopressin analogs are warranted to determine their potential in cancer management. Fil: Ripoll, Giselle Vanina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Garona, Juan. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Pifano, Marina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Farina, Hernán Gabriel. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Gomez, Daniel Eduardo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Alonso, Daniel Fernando. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Following previous metronomic meetings in Marseille (2011), Milano (2014), and Mumbai (2016), the first Latin American metronomic meeting was held in the School of Medical Sciences, National University of Rosario, Rosario, Argentina on 27 and 28 of May, 2016. For the first time, clinicians and researchers with experience in the field of metronomics, coming from different countries in Latin America, had the opportunity of presenting and discussing their work. The talks were organised in three main sessions related to experience in the pre-clinical, and clinical (paediatric and adult) areas. The different presentations demonstrated that the fields of metronomic chemotherapy and repurposing drugs in oncology, known as metronomics, constitute a branch of cancer therapy in permanent evolution, which have strong groups working in Latin America, both in the preclinical and the clinical settings including large, adequately designed randomised studies. It was shown that metronomics offers treatments, which, whether they are combined or not with the standard therapeutic approaches, are not only effective but also minimally toxic, with the consequent improvement of the patient’s quality of life, and inexpensive, a feature very important in low resource clinical settings. The potential use of metronomic chemotherapy was proposed as a cost/effective treatment in low-/middle-income countries, for adjuvant therapy in selected tumours. The fundamental role of the governmental agencies and non-governmental alliances, as the Metronomic Global Health Initiative, in supporting this research with public interest was underlined.

BACKGROUND:Biosimilars are described as biological products that resemble the structure of original biologic therapeutic products, with no clinically meaningful differences in terms of safety and effectiveness from the original. A wide range of biosimilars are under development or are already licensed in many countries. Biosimilars are earning acceptance and becoming a reality for immunotherapy treatments mainly based on the alternatives for the commercial anti-CD20 monoclonal antibody rituximab. The most important mechanism of action reported for this antibody is the induction of antibody-dependent cell cytotoxicity (ADCC), which is associated with the polymorphisms present at the 158 position in the IgG receptor FcγRIIIa.OBJECTIVE:The aim of the study was to validate the functional comparability between the proposed rituximab biosimilar RTXM83 and the original product. To achieve this we assessed the binding capacity and ADCC induction of this biosimilar, taking into account the different FcγRIIIa-158 polymorphisms.METHODS:Binding capacity was evaluated by flow cytometry using CD20 positive cells and a wide range of antibody concentrations. The FcγRIIIa-158 polymorphisms were analyzed by polymerase chain reaction (PCR) followed by allele-specific restriction enzyme digestion. ADCC was measured by a colorimetric lactate dehydrogenase-release assay, using effector cells from donors with different FcγRIIIa-158 polymorphisms.RESULTS:Binding capacity assay showed no differences between both products. Regarding ADCC, a similar relative potency was obtained between both antibodies, showing a higher response for the FcγRIIIa-158 valine/valine (V/V) polymorphism compared to the phenylalanine/phenylalanine (F/F), for both rituximab and RTXM83.CONCLUSION:Our data strongly suggest the biocomparability between the proposed biosimilar and the originator rituximab, in antibody recognition and ADCC activity. Additionally, our results suggest that donors with the FcγRIIIa-158V/V polymorphism induce a higher ADCC response, as has been reported. Fil: Cuello, Héctor Adrián. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Segatori, Valeria Inés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Alberto, Marina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Pesce, Analía. PharmADN; Argentina Fil: Alonso, Daniel Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina Fil: Gabri, Mariano Rolando. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina

Introduction: Racotumomab (originally known as 1E10 mAb) is an anti-idiotype murine IgG1 directed to membrane glycoconjugates expressed in aggressive solid tumors. It was developed as a mirror image of the idiotype of another antibody against N-glycolyl-containing molecules, such as the NeuGcGM3 ganglioside. After a successful phase II/III study, racotumomab formulated in alum was conditionally approved in Latin American countries as maintenance therapy for advanced non-small cell lung cancer. Areas covered: This review analyzes the biology of the target antigen, summarizes preclinical studies and discusses clinical trials in adults and the pediatric experience with racotumomab. Expert opinion: Proper patient selection and combination with chemotherapy, radiotherapy or checkpoint inhibitors appear to be critical issues to maximize the effects of racotumomab vaccination in lung cancer. In a recent phase I clinical trial in children with relapsed or resistant neuroectodermal malignancies, racotumomab was well tolerated and immunogenic, and its evaluation as immunotherapy for high-risk neuroblastoma is warranted. Fil: Gabri, Mariano Rolando. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Cacciavillano, Walter. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría ; Argentina Fil: Chantada, Guillermo Luis. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Alonso, Daniel Fernando. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Telomerase is the enzyme responsible for maintenance of the length of telomeres by addition of guanine-rich repetitive sequences. Telomerase activity is exhibited in gametes and stem and tumor cells. In human somatic cells, proliferation potential is strictly limited and senescence follows approximately 50-70 cell divisions. In most tumor cells, on the contrary, replication potential is unlimited. The key role in this process of the system of the telomere length maintenance with involvement of telomerase is still poorly studied. Undoubtedly, DNA polymerase is not capable of completely copying DNA at the very ends of chromosomes; therefore, approximately 50 nucleotides are lost during each cell cycle, which results in gradual telomere length shortening. Critically short telomeres cause senescence, following crisis and cell death. However, in tumor cells the system of telomere length maintenance is activated. Much work has been done regarding the complex telomere/telomerase as a unique target, highly specific in cancer cells. Telomeres have additional proteins that regulate the binding of telomerase. Telomerase, also associates with a number of proteins forming the sheltering complex having a central role in telomerase activity. This review focuses on the structure and function of the telomere/telomerase complex and its altered behavior leading to disease, mainly cancer. Although telomerase therapeutics are not approved yet for clinical use, we can assume that based on the promising in vitro and in vivo results and successful clinical trials, it can be predicted that telomerase therapeutics will be utilized soon in the combat against malignancies and degenerative diseases. The active search for modulators is justified, because the telomere/telomerase system is an extremely promising target offering possibilities to decrease or increase the viability of the cell for therapeutic purposes.