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Purpose: Diffuse intrinsic pontine glioma is the most aggressive form of high grade glioma in children with no effective therapies. There have been no improvements in survival in part due poor understanding of underlying biology, and lack of representative in vitro and in vivo models. Recently, it has been found feasible to use both biopsy and autopsy tumors to generate cultures and xenograft models. Methods: To further model development, we evaluated the collective international experience from 8 collaborating centers to develop DIPG pre-clinical models from patient-derived autopsies and biopsies. Univariate and multivariate analysis was performed to determine key factors associated with the success of in vitro and in vivo PDX development. Results: In vitro cultures were successfully established from 57% of samples (84.2% of biopsies and 38.2% of autopsies). Samples transferred in DMEM media were more likely to establish successful culture than those transported in Hibernate A. In vitro cultures were more successful from biopsies (84.2%) compared with autopsies (38.2%) and as monolayer on laminin-coated plates than as neurospheres. Primary cultures successfully established from autopsy samples were more likely to engraft in animal models than cultures established from biopsies (86.7% vs. 47.4%). Collectively, tumor engraftment was more successful when DIPG samples were directly implanted in mice (68%), rather than after culturing (40.7%). Conclusion: This multi-center study provides valuable information on the success rate of establishing patient-derived pre-clinical models of DIPG. The results can lead to further optimization of DIPG model development and ultimately assist in the investigation of new therapies for this aggressive pediatric brain tumor.

Diffuse Intrinsic Pontine Gliomas (DIPGs) are the most devastating of all brain tumors. There are no effective treatments, hence almost all children will die of their tumor within 12-months. There is an urgent need for novel effective therapies for this aggressive tumor. We performed a high-throughput drug screen with over 3,570 biologically active, clinically approved compounds against a panel of neurosphere-forming DIPG cells. We identified 7 compounds - auranofin, fenretinide, ivermectin, lanatoside, parthenolide, SAHA and mefloquine - that were confirmed to have potent anti-tumor activity against a panel of DIPG-neurospheres, with minimal effect on normal cells. Using cytotoxicity and clonogenic assays, we found that these drugs were able to inhibit DIPG-neurosphere proliferation and colony formation in vitro. To determine whether the in vitro efficacy could be replicated in vivo, we tested the activity of each of these compounds in an orthotopic DIPG model. Of the agents tested, fenretinide, auranofin and SAHA were the most active anti-tumor agents, significantly enhancing the survival of tumor bearing animals. Mechanistic studies showed fenretinide enhancing apoptotic cell death of DIPG cells via inhibition of PDGFRa transcription and downregulation of the PI3K/AKT/MTOR pathway. We therefore examined the therapeutic efficacy of fenretinide using a second orthotopic model with PDGFRa amplification. We used two different fenretinide formulations which were found to enhance survival. Fenretinide is clinically available with safety data in children. Validation of the activity of Fenretinide in PDGFRa-amplified or overexpressed DIPGs will lead to the development of a clinical trial, allowing the advancement of fenretinide as potentially the first active therapy for DIPG.

// Maria Tsoli 1 , Jie Liu 1 , Laura Franshaw 1 , Han Shen 1 , Cecilia Cheng 1 , MoonSun Jung 2 , Swapna Joshi 1 , Anahid Ehteda 1 , Aaminah Khan 1 , Angel Montero-Carcabosso 3 , Pierre J. Dilda 4 , Philip Hogg 5 and David S. Ziegler 1, 6 1 Targeted Therapies Research Program, Children’s Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Sydney, New South Wales, Australia 2 Experimental Therapeutics Program, Children’s Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Sydney, New South Wales, Australia 3 Preclinical Therapeutics and Drug Delivery Research Program, Department of Oncology, Hospital Sant Joan de Deu, Barcelona, Spain 4 Biophytis, UPMC, BC94, Paris, France 5 ACRF Centenary Cancer Research Program, Centenary Institute, University of Sydney, Camperdown, New South Wales, Australia 6 Kids Cancer Centre, Sydney’s Children Hospital, Randwick, New South Wales, Australia Correspondence to: David S. Ziegler, email: d.ziegler@unsw.edu.au Keywords: DIPG; paediatric brain tumour; mitochondria; mTOR; PDGFR Received: August 08, 2017 Accepted: January 02, 2018 Published: January 08, 2018 ABSTRACT Diffuse Intrinsic Pontine Gliomas (DIPG) are the most devastating of all pediatric brain tumors. They mostly affect young children and, as there are no effective treatments, almost all patients with DIPG will die of their tumor within 12 months of diagnosis. A key feature of this devastating tumor is its intrinsic resistance to all clinically available therapies. It has been shown that glioma development is associated with metabolic reprogramming, redox state disruption and resistance to apoptotic pathways. The mitochondrion is an attractive target as a key organelle that facilitates these critical processes. PENAO is a novel anti-cancer compound that targets mitochondrial function by inhibiting adenine nucleotide translocase (ANT). Here we found that DIPG neurosphere cultures express high levels of ANT2 protein and are sensitive to the mitochondrial inhibitor PENAO through oxidative stress, while its apoptotic effects were found to be further enhanced upon co-treatment with mTOR inhibitor temsirolimus. This combination therapy was found to act through inhibition of PI3K/AKT/mTOR pathway, HSP90 and activation of AMPK. In vivo experiments employing an orthotopic model of DIPG showed a marginal anti-tumour effect likely due to poor penetration of the inhibitors into the brain. Further testing of this anti-DIPG strategy with compounds that penetrate the BBB is warranted.

DIPGs are the most devastating of all brain tumors. There are no effective treatments, hence almost all children will die of their tumor within 12 months. There is an urgent need for novel effective therapies for this aggressive tumor. We performed a high-throughput drug screen with over 3,500 biologically active, clinically approved compounds against a panel of neurosphere-forming DIPG cells. We identified 7 compounds- auranofin, fenretinide, ivermectin, lanatoside, parthenolide, SAHA and mefloquine- that were confirmed to have potent anti-tumor activity against a panel of DIPG-neurospheres, with minimal effect on normal cells. Using cytotoxicity and clonogenic assays, we found that these drugs were able to inhibit DIPG-neurosphere proliferation and colony formation in-vitro. To determine whether the in-vitro efficacy could be replicated in-vivo, we tested the activity of each of these compounds in an orthotopic DIPG model. Of the agents tested, fenretinide and SAHA were the most active anti-tumor agents, significantly enhancing the survival of tumor bearing animals. Mechanistic studies showed fenretinide enhancing apoptotic cell death of DIPG cells via inhibition of PDGFRa transcription and downregulation of the PI3K/AKT/MTOR pathway. We therefore examined the therapeutic efficacy of fenretinide using a second orthotopic model with PDGFRa amplification. We used two different Fenretinide formulations (LYM-X-Sorb and NanoMicelle) which were found to enhance survival. Fenretinide is clinically available with safety data in children. Validation of the activity of Fenretinide in PDGFRa-amplified or overexpressed DIPGs will lead to the development of a clinical trial, allowing the advancement of fenretinide as potentially the first active therapy for DIPG.

Simple Summary Diffuse intrinsic pontine gliomas (DIPGs) are the most aggressive high-grade gliomas known to affect children. Due to the infiltrative nature of the DIPG tumours in the brainstem, they are very difficult to treat. Unfortunately, children succumb to their disease within 1–2 years from their diagnosis. Novel therapeutic treatments are, thus, urgently needed. Using primary cultures and orthotopic models of DIPG, we evaluated the therapeutic efficacy of passionfruit like nanoarchitectures functionalized with human serum albumin and loaded with doxorubicin (NA-HSA-Dox). We found that NA-HSA-Dox were significantly effective at penetrating DIPG spheroids and subsequently at reducing the proliferation and colony formation in DIPG cells. Although an antitumour effect was not observed in orthotopic models of DIPG, NA-HSA-Dox was well tolerated. These study demonstrates the importance of employing brain tumour orthotopic models for the identification of novel therapies and the need to develop treatments that effectively cross the blood brain barrier. Abstract Diffuse Intrinsic Pontine Gliomas (DIPGs) are highly aggressive paediatric brain tumours. Currently, irradiation is the only standard treatment, but is palliative in nature and most patients die within 12 months of diagnosis. Novel therapeutic approaches are urgently needed for the treatment of this devastating disease. We have developed non-persistent gold nano-architectures (NAs) functionalised with human serum albumin (HSA) for the delivery of doxorubicin. Doxorubicin has been previously reported to be cytotoxic in DIPG cells. In this study, we have preclinically evaluated the cytotoxic efficacy of doxorubicin delivered through gold nanoarchitectures (NAs-HSA-Dox). We found that DIPG neurospheres were equally sensitive to doxorubicin and doxorubicin-loaded NAs. Colony formation assays demonstrated greater potency of NAs-HSA-Dox on colony formation compared to doxorubicin. Western blot analysis indicated increased apoptotic markers cleaved Parp, cleaved caspase 3 and phosphorylated H2AX in NAs-HSA-Dox treated DIPG neurospheres. Live cell content and confocal imaging demonstrated significantly higher uptake of NAs-HSA-Dox into DIPG neurospheres compared to doxorubicin alone. Despite the potency of the NAs in vitro, treatment of an orthotopic model of DIPG showed no antitumour effect. This disparate outcome may be due to the integrity of the blood-brain barrier and highlights the need to develop therapies to enhance penetration of drugs into DIPG.

Despite the increase in overall child cancer survival rates, pediatric malignancies such as high-risk neuroblastoma, high-risk leukemias (including MLL-translocated infant ALL), and aggressive brain tumors (including DIPG) remain refractory to current multimodal therapies. We have been developing new treatment approaches for these aggressive childhood cancers by (i) utilizing novel targeted therapies either alone or combined with other new agents or established chemotherapeutic drugs, and (ii) by developing new drugs that target key pathways in these child cancers. In neuroblastoma, we have targeted polyamines, showing that combined inhibition of polyamine synthesis by the ODC1 inhibitor DFMO, and of polyamine uptake using the small-molecule drug AMXT 1501, is highly effective at inhibiting tumor growth in Th-MYCN transgenic mice. This combination also shows great efficacy in preclinical models of DIPG, and clinical trials for these diseases are now being planned. We are also targeting metabolism of arginine, the precursor of ornithine, using the pegylated-recombinant arginase BCT-100, which significantly delays tumor development and prolongs survival of neuroblastoma-prone Th-MYCN mice. We have further shown that combining BCT-100 with either DFMO or conventional chemotherapy results in increased survival benefit. CBL0137 is a nontoxic novel anticancer drug currently in phase I trial for adult refractory and relapsed cancers. CBL0137 destabilizes nucleosomes and traps histone chaperone FACT into chromatin, thereby modulating several anticancer mechanisms. We have shown that CBL0137 is effective in mouse models of neuroblastoma, MLL-rearranged leukemia, and DIPG, and that its action is potentiated by the HDAC inhibitor, panobinostat. Moreover, we have developed OT-82, a novel nontoxic NAMPT inhibitor with impressive anticancer activity against mouse models of high-risk childhood ALL, potentiating standard-of-care drugs, and showing similar efficacy as the three-drug induction-type treatment used for pediatric ALL. In addition, for all Australian children with high-risk malignancies, we have developed the Zero Childhood Cancer national precision medicine program. ZERO utilizes whole-genome and whole-transcriptome sequencing, methylation profiling, and where possible, in vitro and in vivo drug testing. To date (July 2019), 74% of 207 patients on the national clinical trial have received a Multidisciplinary Tumor Board recommendation (therapy, germline referral, or change of diagnosis), and of 25 patients with evaluable response data thus far who have received the ZERO recommended therapy, a significant proportion have had a complete response, partial response, or maintained stable disease. Moreover, early experience with drug efficacy studies suggests these data may corroborate genomic therapeutic recommendations and may also identify unanticipated active therapeutics. Citation Format: Michelle Haber, Laura Gamble, Lin Xiao, Ruby Pandher, Klaartje Somers, Jayne Murray, Aaminah Khan, Denise Yu, Laura Franshaw, Mark R. Burns, Maria Tsoli, Anahid Ehteda, Anthony Cesare, Aisling O’Connor, Francis Mussai, Carmela de Santo, Paul Cheng, Lioubov Korotchkina, Katerina Gurova, Vanessa Tyrrell, Emily Mould, Loretta Lau, Dong Anh Khuong Quang, Chelsea Mayoh, Greg Arndt, Paulette Barahona, Tim Failes, Jamie Fletcher, Noemi Fuentes- Bolanos, Marie-Emilie Gauthier, Andrew Gifford, Dylan Grebert-Wade, Alvin Kamili, Amit Kumar, Sumanth Nagabushan, Tracey O’Brien, Patrick Strong, Alexandra Sherstyuk, David Thomas, Toby Trahair, Katherine Tucker, Meera Warby, Marie Wong, Jinhan Xie, Kathryn Evans, Richard Lock, Olga B. Chernova, Michelle Henderson, Andrei V Gudkov, Paul Ekert, Mark J. Cowley, Glenn M. Marshall, David S. Ziegler, Murray D. Norris. Molecular targeted therapies and precision medicine for children with neuroblastoma and other refractory malignancies [abstract]. In: Proceedings of the AACR Special Conference on the Advances in Pediatric Cancer Research; 2019 Sep 17-20; Montreal, QC, Canada. Philadelphia (PA): AACR; Cancer Res 2020;80(14 Suppl):Abstract nr IA13.

Diffuse Intrinsic Pontine Glioma (DIPG) is the most aggressive form of malignant glioma to affect children. DIPG tumours cannot be surgically removed, do not respond to chemotherapy and are highly resistant to radiotherapy. Almost all children present with a short history of symptoms, fast neurological decline and rapid tumour progression. With almost all children with DIPG dying within only one year of diagnosis, new and innovative treatment strategies are urgently needed to counter these devastating tumours. We have found multiple regulators of the cell cycle are overexpressed in DIPG. Polo-like Kinase 1 (PLK1) represents the most promising target within the cell cycle apparatus. PLK1 controls cell cycle progression, cellular response to DNA damage and regulates cell cycle re-entry following arrest. We examined the therapeutic potential of 3 blood brain barrier permeable PLK1 inhibitors readily amenable for rapid clinical translation (BI2536/GSK461364/BI6727). Each exhibited unprecedented anti-proliferative effects against our panel of DIPG cultures at exceptionally low nanomolar potency, decreasing clonogenic abilities and increasing arrest at the G2 checkpoint. We found PLK1 inhibition influences one of the major oncogenic pathways in DIPG, the Phosphoinositide 3-kinase (PI3K) pathway. Interestingly, several key tumour promoting aberrations in this pathway were corrected upon PLK1 inhibition. We therefore examined whether the efficacy of PLK1 inhibitors can be further enhanced through combination with agents that target this pathway. We found cytotoxic activity of PLK1 inhibitors are synergistically enhanced upon addition of the PI3K inhibitor BKM120. We also identified a novel highly potent therapeutic approach for DIPG combining PLK1 inhibitors with temsirolimus (an mTOR inhibitor). In our highly aggressive orthotopic model of paediatric supratentorial High Grade Glioma, PLK1 inhibition significantly and potently enhanced animal survival. We are currently testing PLK1 inhibitors in combination with irradiation in our patient-derived in vivo model of DIPG with preliminary results indicating prolonged animal survival.

Background Diffuse intrinsic pontine glioma (DIPG), or high-grade brainstem glioma (BSG), is one of the major causes of brain tumor-related deaths in children. Its prognosis has remained poor despite numerous efforts to improve survival. Panobinostat, a histone deacetylase inhibitor, is a targeted agent that has recently shown pre-clinical efficacy and entered a phase I clinical trial for the treatment of children with recurrent or progressive DIPG. Methods A collaborative pre-clinical study was conducted using both a genetic BSG mouse model driven by PDGF-B signaling, p53 loss, and ectopic H3.3-K27M or H3.3-WT expression and an H3.3-K27M orthotopic DIPG xenograft model to confirm and extend previously published findings regarding the efficacy of panobinostat in vitro and in vivo. Results In vitro, panobinostat potently inhibited cell proliferation, viability, and clonogenicity and induced apoptosis of human and murine DIPG cells. In vivo analyses of tissue after short-term systemic administration of panobinostat to genetically engineered tumor-bearing mice indicated that the drug reached brainstem tumor tissue to a greater extent than normal brain tissue, reduced proliferation of tumor cells and increased levels of H3 acetylation, demonstrating target inhibition. Extended consecutive daily treatment of both genetic and orthotopic xenograft models with 10 or 20 mg/kg panobinostat consistently led to significant toxicity. Reduced, well-tolerated doses of panobinostat, however, did not prolong overall survival compared to vehicle-treated mice. Conclusion Our collaborative pre-clinical study confirms that panobinostat is an effective targeted agent against DIPG human and murine tumor cells in vitro and in short-term in vivo efficacy studies in mice but does not significantly impact survival of mice bearing H3.3-K27M-mutant tumors. We suggest this may be due to toxicity associated with systemic administration of panobinostat that necessitated dose de-escalation.

There are two errors and one omission in the original article. Author Gottardo's correct name is Nicholas G. Gottardo, author Hulleman's correct affiliation is no. 3 (VUMC, Amsterdam), and the Acknowledgements should include the following sentence: "We would like to thank Dr Angel Montero Carcaboso (Hospital Sant Joan de Deu, Barcelona, Spain) for generously supplying the HSJD-DIPG007 cells."

Essentials Cancer cachexia and cancer-associated thrombosis have not previously been mechanistically linked. We assessed thrombin generation and coagulation parameters in cachectic C26 tumor-bearing mice. C26 mice are hypercoagulable, partially corrected by blocking tumor derived interleukin-6. Coagulability and anti-inflammatory interventions may be clinically important in cancer cachexia.Background Cancer cachexia and cancer-associated thrombosis are potentially fatal outcomes of advanced cancer, which have not previously been mechanistically linked. The colon 26 (C26) carcinoma is a well-established mouse model of complications of advanced cancer cachexia, partially dependent on high levels of interleukin-6 (IL-6) produced by the tumor. Objectives To assess if cancer cachexia altered the coagulation state and if this was attributable to tumor IL-6 production. Methods In male BALB/c*DBA2 (F1 hybrid) mice with a C26 tumor we used modified calibrated automated thrombogram and fibrin generation (based on overall hemostatic potential) assays to assess the functional coagulation state, and also examined fibrinogen, erythrocyte sedimentation rate (ESR), platelet count, tissue factor pathway inhibitor (TFPI) and hepatic expression of coagulation factors by microarray. C26 mice were compared with non-cachectic NC26, pair-fed and sham control mice. IL-6 expression in C26 cells was knocked down by lentiviral shRNA constructs. Results C26 mice with significant weight loss and highly elevated IL-6 had elevated thrombin generation, fibrinogen, ESR, platelets and TFPI compared with all control groups. Fibrin generation was elevated compared with pair-fed and sham controls but not compared with NC26 tumor mice. Hepatic expression of coagulation factors and fibrinolytic inhibitors was increased. Silencing IL-6 in the tumor significantly, but incompletely, attenuated the increased thrombin generation, fibrinogen and TFPI. Conclusions Cachectic C26 tumor-bearing mice are in a hypercoagulable state, which is partly attributable to IL-6 release by the tumor. The findings support the importance of the coagulation state in cancer cachexia and the clinical utility of anti-inflammatory interventions.

Background Bromelain and N-acetylcysteine are two natural, sulfhydryl-containing compounds with good safety profiles which have been investigated for their benefits and application in health and disease for more than fifty years. As such, the potential values of these agents in cancer therapy have been variably reported in the literature. In the present study, the efficacy of bromelain and N-acetylcysteine in single agent and combination treatment of human gastrointestinal carcinoma cells was evaluated in vitro and the underlying mechanisms of effect were explored. Methods The growth-inhibitory effects of bromelain and N-acetylcysteine, on their own and in combination, on a panel of human gastrointestinal carcinoma cell lines, including MKN45, KATO-III, HT29-5F12, HT29-5M21 and LS174T, were assessed by sulforhodamine B assay. Moreover, the influence of the treatment on the expression of a range of proteins involved in the regulation of cell cycle and survival was investigated by Western blot. The presence of apoptosis was also examined by TUNEL assay. Results Bromelain and N-acetylcysteine significantly inhibited cell proliferation, more potently in combination therapy. Drug-drug interaction in combination therapy was found to be predominantly synergistic or additive. Mechanistically, apoptotic bodies were detected in treated cells by TUNEL assay. Furthermore, Western blot analysis revealed diminution of cyclins A, B and D, the emergence of immunoreactive subunits of caspase-3, caspase-7, caspase-8 and cleaved PARP, withering or cleavage of procaspase-9, overexpression of cytochrome c, reduced expression of anti-apoptotic Bcl-2 and pro-survival phospho-Akt, the emergence of the autophagosomal marker LC3-II and deregulation of other autophagy-related proteins, including Atg3, Atg5, Atg7, Atg12 and Beclin 1. These results were more prominent in combination therapy. Conclusion We report for the first time to our knowledge the growth-inhibitory and cytotoxic effects of bromelain and N-acetylcysteine, in particular in combination, on a panel of gastrointestinal cancer cell lines with different phenotypes and characteristics. These effects apparently resulted from cell cycle arrest, apoptosis and autophagy. Towards the development of novel strategies for the enhancement of microscopic cytoreduction, our results lay the basis for further evaluation of this formulation in locoregional approaches to peritoneal surface malignancies and carcinomatosis.

Diffuse Intrinsic Pontine Gliomas (DIPGs) are the most devastating of all brain tumours. They mostly affect young children and, as there are no effective treatments, almost all will succumb to the disease within 12 months. TRX-E-009-1 is a novel anti-cancer agent in preclinical development with broad anti-cancer activity. Ecto-NOX disulfide-thiol exchanger 2 (ENOX2) is the putative target of benzopyran molecules, a family to which TRXE-009-1 belongs. We have found that ENOX2 is significantly over-expressed in our panel of patient-derived DIPG cell lines, while it is completely absent from normal astrocytes. Given these differences in expression, we examined the anti-tumour activity of TRX-E-009-1 against our DIPG neurosphere cultures and found striking tumour specific activity with an IC50 ranging from 20–100 nM with no activity against normal human astrocyte cells (NHAs). We showed that TRX-E-009-1 exerts its anti-proliferative effect through the induction of apoptotic pathways with marked increases in the levels of cleaved caspase 3 and cleaved PARP. TRX-E-009-1 also suppresses the expression of PDGFR-α while enhancing histone H3.3K27me3 methylation. In a DIPG orthotopic model, survival of mice treated with TRX-E-009-1 was significantly increased compared with controls (median survival control 70.5 days vs. 97 days TRX-E-009-1 treated; P = 0.0029). Further, in vitro, the combination of TRX-E-009-1 with a compound currently under clinical investigation against glioma significantly improved cytotoxic activity against DIPG neurospheres. Our findings indicate that TRX-E-009-1 represents a novel, potentially effective therapy for children with DIPG.

Pseudomyxoma peritonei (PMP, ORPHA26790) is a clinical syndrome characterized by progressive dissemination of mucinous tumors and mucinous ascites in the abdomen and pelvis. PMP is a rare disease with an estimated incidence of 1–2 out of a million. Clinically, PMP usually presents with a variety of unspecific signs and symptoms, including abdominal pain and distention, ascites or even bowel obstruction. It is also diagnosed incidentally at surgical or non-surgical investigations of the abdominopelvic viscera. PMP is a neoplastic disease originating from a primary mucinous tumor of the appendix with a distinctive pattern of the peritoneal spread. Computed tomography and histopathology are the most reliable diagnostic modalities. The differential diagnosis of the disease includes secondary peritoneal carcinomatoses and some rare peritoneal conditions. Optimal elimination of mucin and the mucin-secreting tumor comprises the current standard of care for PMP offered in specialized centers as visceral resections and peritonectomy combined with intraperitoneal chemotherapy. This multidisciplinary approach has reportedly provided a median survival rate of 16.3 years, a median progression-free survival rate of 8.2 years and 10- and 15-year survival rates of 63% and 59%, respectively. Despite its indolent, bland nature as a neoplasm, PMP is a debilitating condition that severely impacts quality of life. It tends to be diagnosed at advanced stages and frequently recurs after treatment. Being ignored in research, however, PMP remains a challenging, enigmatic entity. Clinicopathological features of the PMP syndrome and its morbid complications closely correspond with the multifocal distribution of the secreted mucin collections and mucin-secreting implants. Novel strategies are thus required to facilitate macroscopic, as well as microscopic, elimination of mucin and its source as the key components of the disease. In this regard, MUC2, MUC5AC and MUC5B have been found as the secreted mucins of relevance in PMP. Development of mucin-targeted therapies could be a promising avenue for future research which is addressed in this article.

Afshin Amini, Anahid Ehteda, Samar Masoumi Moghaddam, Javed Akhter, Krishna Pillai, David Lawson Morris Department of Surgery, St George Hospital, University of New South Wales, Sydney, NSW, Australia Background: Bromelain is a pineapple stem extract with a variety of therapeutic benefits arising from interaction with a number of different biological processes. Several preclinical studies and anecdotal clinical observations have reported the anticancer properties of bromelain. In the present study, we investigated the cytotoxic effects of bromelain in four human cancer cell lines of gastrointestinal origin and the mechanisms involved. Methods: The gastric carcinoma cell lines (KATO-III and MKN45) and two chemoresistant subpopulations of the HT29 colon adenocarcinoma cell line (HT29-5M21 and HT29-5F12) were treated with a range of concentrations of bromelain, as well as with cisplatin as a positive control. The effect of bromelain on the growth and proliferation of cancer cells was determined using a sulforhodamine B assay after 72 hours of treatment. Expression of apoptosis-associated proteins in MKN45 cells treated with bromelain was analyzed by Western blotting. Results: Data from our sulforhodamine B assay showed that bromelain inhibited proliferation of HT29-5F12, HT29-5M21, MKN45, and KATO-III cells, with respective half maximal inhibitory concentration values of 29, 34, 94, and 142 µg/mL. Analyzing the expression of proapoptotic and antiapoptotic proteins in bromelain-treated MKN45 cells, we observed activation of the caspase system, cleavage of PARP and p53, overexpression of cytochrome C, attenuation of phospho-Akt and Bcl2, and removal of MUC1. Apart from the caspase-dependent apoptosis observed, emergence of cleaved p53 supports a direct, extranuclear apoptotic function of p53. Moreover, interrupted Akt signaling and attenuation of Bcl2 and MUC1 oncoproteins suggest impaired survival of cancer cells. Conclusion: Our findings collectively indicate that bromelain exerts cytotoxic effects in a panel of human gastric and colon carcinoma cells. Our study of MKN45 cells implicated different mechanisms in bromelain-induced cell death. While promoting apoptosis with involvement of the caspase system and extranuclear p53, bromelain also appears to impair cancer cell survival by blocking the Akt pathway and attenuating Bcl2 and MUC1 oncoproteins. Keywords: bromelain, cytotoxicity, gastrointestinal carcinoma, MKN45, KATO-III, HT29

normally poor however, cytoreductive surgery and hyperthermic intraperitoneal chemotherapy has increased survival in some patients. Hence, new therapies are needed. MUC1 is a glycosylation dependant protein associated with tumour invasiveness, metastasis and chemo resistance. Bromelain, a cysteine proteinase, hydrolyses glycosidic bonds, whilst N-Acetyl cysteine reduces disulphide bonds in glycoprotein. Hence, we investigated the anti-tumour effect of these agents in MUC 1 expressing MPM cell lines. Materials and Methods: The cell lines were treated to various concentrations of bromelain, NAC and combinations of NAC + bromelain, NAC + bromelain + cisplatin or 5-FU. Their cell viabilities were assessed at 48 hours with sulfhordamine B assay. Finally, with western blotting, the effect of NAC and the combination of NAC + bromelain on cellular survival proteins were investigated. Results: Combination of NAC (10 mM) with bromelain (75 ug/ml) showed 97% and 88% cell proliferation inhibition in YOU and PET cells, respectively. In triple combination, the addition of cisplatin to only 5.0 mM NAC and bromelain increased cytotoxicity in YOU cells but absent at 10.0 mM NAC concentration. However, in PET cells, triple combinations with cisplatin had no effect. The addition of 5-FU in triple combinations showed an increase in cytotoxicity with 5.0 mM NAC and bromelain in YOU cells. No increase in cytotoxicity was seen with addition of 10 mM NAC. In PET cells, the addition 5-FU to 5.0 mM NAC + 50 ug/ml bromelain, enhanced cytotoxicity significantly but was absent at all other combinations. Conclusion: The combination of bromelain and NAC may be developed as anti-tumour agents for treating MPM, with a possible role in combined therapy with current chemotherapeutic agents.

Mucin is well understood to be an adverse prognostic factor in some cancers. We previously reported that a combination of Bromelain (BR) and N-acetylcysteine (NAC) were synergistic in dissolving pseudomyxoma peritonei mucin, had direct in vitro cytotoxic effects on some gastrointestinal cancer cells and sensitized them to some chemotherapy agents. In the present study, we aimed to evaluate the growth-inhibitory effect of BR and NAC as single agent or combination therapy in nude mice models of gastrointestinal cancer. Nude mice received 2 million and 1 million cells of MKN45 (gastric) and LS174T (colorectal) by intraperitoneal injection. At day 14 and 7 post inoculation for MKN45 and LS174T cells, respectively, animals were intraperitoneally administrated BR (3, 6 mg/kg), NAC (300, 500 mg/kg) or their combination every other day over 12 days for MKN45 and 17 days for LS174T models. At the end of the study, the animals were euthanized, the number of peritoneal nodules and their weight were collected, and the peritoneal tumors were subjected to immunohistochemistry for evaluation of MUC2. No toxicity was observed during the experiment. At necropsy, highly significant reductions in the number of tumor nodules and tumor burden were observed, in particular in the combination group, where almost complete inhibition in LS174T group was found. There was more than 95% and 70% decreases in tumor burden and tumor nodules, respectively, in LS174T group after combination treatment. For MKN45 model, the reductions in tumor burden and tumor nodules in combination groups were more than 60% and 70%, respectively. Performing immunohistochemistry on tumor samples, MUC2 staining of the LS174T xenografts showed a greater than 60% reduction of cytoplasmic staining. To the best of our knowledge, this is the first report of the in vivo use of this combination with synergistic inhibition of human gastric and colorectal cancers. The combination of BR and NAC in mucin secreting gastrointestinal tumors is interesting and could be of potential value in peritoneal cancer. Citation Format: Afshin Amini, Samar Masoumi-Moghaddam, Anahid Ehteda, Winston Liauw, Javed Akhter, Krishna Pilai, David L. Morris. Synergistic inhibition of human gastric and colorectal cancers by Bromelain and N-acetylcysteine: An in vivo study. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-007. doi:10.1158/1538-7445.AM2015-LB-007

Background Malignant peritoneal mesothelioma (MPM) is a rare neoplasm of the peritoneum that is causally related to asbestos exposure. Nonspecific symptoms and late diagnosis result in poor survival ( Methods MUC1 expression was assessed using immunofluorescent probes with cells grown on cover slips and western blot analysis on cell lysates. Cell lines were treated with various concentrations of bromelain, and after 4 h and 72 h their viability was assessed using standard sulforhodamine assays. The cells were also treated with combinations of bromelain and cytotoxic drugs (cisplatin or fluorouracil) and their viability assessed at 72 h. The effects of bromelain on cellular survival proteins were investigated with western blotting. Findings PET cells expressed more MUC1 than YOU cells. Cell viability of both PET and YOU cells were adversely affected by bromelain, with PET cells being slightly resistant. The addition of bromelain increased the cytotoxicity of cisplatin significantly in both cell lines. However, combining fluorouracil with bromelain did not show a significant increase in cytotoxicity. Bromelain induced cell death via apoptosis and autophagy. Interpretation Bromelain has potential as a therapeutic agent in malignant peritoneal mesothelioma.

Background Albendazole (ABZ) is a microtubule-targeting anthelmintic with a remarkable activity against a variety of human cancer cells. In this study, we examined if the antitumor activity of ABZ could be enhanced by its combination with other microtubule-binding agents. Methods The interactions between ABZ and microtubule-binding agents, paclitaxel, vinblastine, colchicine, and 2-methoxyestradiol were characterized using median effect analysis method in HCT-116 colorectal cancer cells and DU145 prostate cancer cell line. The mechanism underlying the synergistic interaction related to tubulin polymerization and apoptosis was then investigated. Finally, the effect of the combination therapy on the survival of HCT-116 tumor-bearing nude mice was evaluated. Results Among the tested drugs, a synergistic anti-proliferative effect was observed with the combination of low concentrations of ABZ plus colchicine and ABZ plus 2-methoxyestradiol (2ME). Exploring the mechanism of the interaction between ABZ and 2ME revealed that the combination therapy synergistically activated the extrinsic pathway of apoptosis. Consistent with in vitro results, the combination of low concentration of ABZ with 2ME prolonged the survival of mice-bearing HCT-116 tumors. High concentration of ABZ in combination with 2ME, however, proved to be less effective than ABZ alone. Conclusions The combination of low doses of ABZ and 2ME has shown promising results in our pre-clinical model. Additionally, the finding that the combination of two microtubule-binding agents that share the same binding site can act synergistically may lead to the development of new therapeutic strategies in cancer treatment.