Search

Poly(polyethylene glycol methyl ether methacrylate-co-methacrylic acid)-block-poly(methylmethacrylate)P(PEGMEMA-co-MAA)-b-PMMA block copolymerwere prepared via RAFT (reversible addition–fragmentation chaintransfer) polymerization and subsequently self-assembled into micellesas a drug delivery carrier for albendazole (ABZ). For comparison,the micelles were additionally cross-linked to study the effect ofshell-cross-linking on the biological activity. The hydrodynamic diameterof cross-linked and un-cross-linked micelles was approximately 40nm in both cases. While the cross-linked micelle was stable even ingood solvents for both blocks, the un-cross-linked micelle was foundto lose its integrity in cell growth media. Crosslinking had a major effect on the rate of drug release reducing it dramatically from 50% (uncrosslinked) to around 20% (crosslinked) over a 30 h incubation period. Both drug delivery systems were tested on humanprostate cancer cells (PC-3, DU-145) and human ovarian cancer cells(OVCAR-3, A-2780). No toxic effects were measured with the unloadedmicelle while the ABZ loaded un-cross-linked micelle lead to IC50values between 0.2 and 0.9 μM depending on the cellline. The IC50dropped to values between 0.006 and 0.06μM, depending on cell line, once the micelles were stabilizedby cross-linking. Three treatment cycles with ABZ for one day, followedby two days incubation in media using ABZ-loaded drug carriers ledto complete cell death even at low concentrations in the case of thecross-linked micelle only. Cellular uptake has been studied usingfluorescently labeled micelles and Nile red as model drug, showingcell uptake above the CMC but no micelle uptake below the CMC. Additionalbiological studies, such as colony formation assay and tubulin disorganizationtests, were also performed to gain more insight into the effect ofcross-linking of the shell of the micelle. In conclusion, shell-cross-linkingis highly recommended, even for glassy micelles, for an efficientcellular uptake at low concentrations. [ABSTRACT FROM AUTHOR]

MUC1 is associated with cellular transformation and tumorigenicity and is considered as an important tumor-associated antigen (TAA) for cancer therapy. We previously reported that anti-MUC1 monoclonal antibody C595 (MAb C595) plus docetaxel (DTX) increased efficacy of DTX alone and caused cultured human epithelial ovarian cancer (EOC) cells to undergo apoptosis. To further study the mechanisms of this combination-mediated apoptosis, we investigated the effectiveness of this combination therapy in vivo in an intraperitoneal (i.p.) EOC mouse model. OVCAR-3 cells were implanted intraperitoneally in female athymic nude mice and allowed to grow tumor and ascites. Mice were then treated with single MAb C595, DTX, combination test (MAb C595 and DTX), combination control (negative MAb IgG3 and DTX) or vehicle control i.p for 3 weeks. Treated mice were killed 4 weeks post-treatment. Ascites volume, tumor weight, CA125 levels from ascites and survival of animals were assessed. The expression of MUC1, CD31, Ki-67, TUNEL and apoptotic proteins in tumor xenografts was evaluated by immunohistochemistry. MAb C595 alone inhibited i.p. tumor growth and ascites production in a dose-dependent manner but did not obviously prevent tumor development. However, combination test significantly reduced ascites volume, tumor growth and metastases, CA125 levels in ascites and improved survival of treated mice compared with single agent-treated mice, combination control or vehicle control-treated mice (P,0.05). The data was in a good agreement with that from cultured cells in vitro. The mechanisms behind the observed effects could be through targeting MUC1 antigens, inhibition of tumor angiogenesis, and induction of apoptosis. Our results suggest that this combination approach can effectively reduce tumor burden and ascites, prolong survival of animals through induction of tumor apoptosis and necrosis, and may provide a potential therapy for advanced metastatic EOC. [ABSTRACT FROM AUTHOR]

Background: Emerging reports suggest resistance, increased tumor invasiveness and metastasis arising from treatment with drugs targeting vascular endothelial growth factor (VEGF). It is believed that increased tumoral hypoxia plays a prominent role in the development of these phenomena. Inhibition of tumoral hypoxia inducible factor (HIF- 1α) is thus becoming an increasingly attractive therapeutic target in the treatment of cancer. We hypothesized that the anti-VEGF effect of albendazole (ABZ) could be mediated through inhibition of tumoral HIF-1α. Method: In vitro, the effects of ABZ on HIF-1α levels in human ovarian cancer cells (OVCAR-3) were investigated using hypoxic chamber or desferrioxamine (DFO) induced-hypoxia. In vivo, the effects of ABZ (150 mg/kg, i.p., single dose) on the tumor levels of HIF-1α and VEGF protein and mRNA were investigated by western blotting, RT-PCR and real time- PCR. Results: In vitro, ABZ inhibited cellular HIF-1α protein accumulation resulting from placement of cells under hypoxic chamber or exposure to DFO. In vivo, tumors excised from vehicle treated mice showed high levels of both HIF-1α and VEGF. Whereas, tumoral HIF-1α and VEGF protein levels were highly suppressed in ABZ treated mice. Tumoral VEGFmRNA (but not HIF-1αmRNA) was also found to be highly suppressed by ABZ. Conclusion: These results demonstrate for the first time the effects of an acute dose of ABZ in profoundly suppressing both HIF-1α and VEGF within the tumor. This dual inhibition may provide additional value in inhibiting angiogenesis and be at least partially effective in inhibiting tumoral HIF-1α surge, tumor invasiveness and metastasis. [ABSTRACT FROM AUTHOR]

The inhibitory effect of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) on the proliferation of a number of human and rat liver cancer cell lines has recently been reported. In this study we have demonstrated that these cell lines express functional receptors able to specifically bind [3H]1,25-(OH)2D3. The highest level of functional receptor were found in the human liver cancer cell line HepG2 which had previously been shown to be the most sensitive in 1,25-(OH)2D3 growth inhibition assays. The identity of the binding protein with the Vitamin D3 receptor was confirmed by PCR analysis of HepG2 cell mRNA. Additionally, the inhibitory effect of 1,25-(OH)2D3 on growth of the human liver cancer cell line HepG2 resulted from arrest in the G0/G1 phase of the cell cycle. Increases in the fraction of cells in G0/G1 were dependent upon the concentration of 1,25-(OH)2D3 and were accompanied by complementary decreases in the number of cells in S phase. There was no change in the number of cells in G2+M at any concentration of the hormone. Clonal growth of HepG2 cells in response to 1,25-(OH)2D3 was also dose dependent over three orders of magnitude, thus indicating heterogeneity in cell cycle arrest by this hormone. [Copyright &y& Elsevier]

In women, epithelial ovarian cancer is the leading cause of gynaecological malignancy-related deaths. Development of resistance to standard platinum and taxane based chemotherapy and recurrence of the disease necessitate development of novel drugs to halt disease progression. An established concept is to target molecular and signaling pathways that substantially contribute to development of drug resistance and disease progression. We have previously shown that, monepantel (MPL) a novel small molecule acetonitrile derivative is highly effective in suppressing growth, proliferation and colony formation of ovarian cancer cells. These effects are achieved through inhibition of the mTOR/p70S6K pathway in cancer cells. The present study was conducted to find in vivo corroboration and explore the effect of MPL om other growth stimulating putative signaling pathways. Here, female nude mice with subcutaneous OVCAR-3 xenografts were treated with 25 and 50 mg/kg doses of MPL administered (IP) three times weekly for 2 weeks. At the doses employed, MPL was modestly effective at suppressing tumor growth, but highly effective in inhibiting, mTOR, P70S6K and 4EBP1. There were also modest reductions in tumor cyclin D1 and retinoblastoma protein expression. Furthermore, it was found that MPL treatment causes down-regulation of IGF-1R, and c-MYC thus unveiling new dimensions to the growing antitumor actions of this potential anticancer drug. MPL treatment led to reduced tumor volume and weights without causing any detectable side effects. Coupled with the recent human safety data published on this molecule, expanded future trials are highly anticipated., Competing Interests: None., (AJCR Copyright © 2021.)

Hypoxia-inducible factor (HIF)-1α is the key cellular survival protein under hypoxia, and is associated with tumor progression and angiogenesis. We have recently shown the inhibitory effects of minocycline on ovarian tumor growth correlated with attenuation of vascular endothelial growth factor (VEGF) and herein report a companion laboratory study to test if these effects were the result of HIF-1α inhibition. In vitro, human ovarian carcinoma cell lines (A2780, OVCAR-3 and SKOV-3) were utilized to examine the effect of minocycline on HIF-1 and its upstream pathway components to elucidate the underlying mechanism of action of minocycline. Mice harboring OVCAR-3 xenografts were treated with minocycline to assess the in vivo efficacy of minocycline in the context of HIF-1. Minocycline negatively regulated HIF-1α protein levels in a concentration-dependent manner and induced its degradation by a mechanism that is independent of prolyl-hydroxylation. The inhibition of HIF-1α was found to be associated with up-regulation of endogenous p53, a tumor suppressor with confirmed role in HIF-1α degradation. Further studies demonstrated that the effect of minocycline was not restricted to proteasomal degradation and that it also caused down-regulation of HIF-1α translation by suppressing the AKT/mTOR/p70S6K/4E-BP1 signaling pathway. Minocycline treatment of mice bearing established ovarian tumors, led to suppression of HIF-1α accompanied by up-regulation of p53 protein levels and inactivation of AKT/mTOR/p70S6K/4E-BP1 pathway. These data reveal the therapeutic potential of minocycline in ovarian cancer as an agent that targets the pro-oncogenic factor HIF-1α through multiple mechanisms.

We have recently shown that the novel anthelmintic drug monepantel (MPL) inhibits growth, proliferation and colony formation, arrests the cell cycle and induces cleavage of PARP-1 in ovarian cancer cell lines. Here we report on the mechanism behind the anticancer properties of MPL. The cytotoxic effect of MPL on ovarian cancer cells (OVCAR-3 and A2780) was investigated employing a panel of tests used for the detection of apoptosis and autophagy. Apoptosis and autophagy were defined by caspase activity, DNA-laddering, Annexin-V and acridine orange (AO) staining. Autophagy markers such as LC3B, SQSTM1/p62 and mammalian target of rapamycin (mTOR) pathway related proteins were assessed by western blotting and ELISA techniques. MPL did not activate caspases 3 or 8, nor did it alter the percentage of Annexin V positive stained cells. Failure to cause DNA laddering and the inability of z-VAD-fmk to block the MPL antiproliferative effects led to the ruling out of apoptosis as the mechanism behind MPL-induced cell death. On the other hand, accumulation of acidic vacuoles with distinct chromatin morphology and an increase in punctuate localization of green fluorescent protein-LC3B, and MPL-induced changes in the expression of SQSTM1/p62 were all indicative of MPL-induced autophagy. Consistent with this, we found inhibition of mTOR phosphorylation leading to suppression of the mTOR/p70S6K signalling pathway. Our findings provide the first evidence to show that MPL triggers autophagy through the deactivation of mTOR/p70S6K signalling pathway.

Monepantel (MPL) is a new anthelmintic agent approved for the treatment of nematode infections in farm animals. As a nematicide, it acts through a nematode-specific nicotinic receptor subtype which explains its exceptional safety in rodents and mammals. In the present study, we evaluated its potential as an anticancer agent. In vitro treatment of epithelial ovarian cancer cells with MPL resulted in reduced cell viability, inhibition of cell proliferation and suppression of colony formation. Proliferation of human ovarian surface epithelial cells and other non-malignant cells were however minimally affected. MPL-induced inhibition was found to be independent of the acetylcholine nicotinic receptor (nAChR) indicating that, its target in cancer cells is probably different from that in nematodes. Analysis of MPL treated cells by flow cytometry revealed G1 phase cell cycle arrest. Accordingly, MPL treated cells expressed reduced levels of cyclins D1 and A whereas cyclin E2 expression was enhanced. Consistent with a G1 phase arrest, cellular levels of cyclin dependent kinases (CDKs) 2 and 4 were lower, whereas expression of CDK inhibitor p27(kip) was increased. In cells expressing the wild-type p53, MPL treatment led to increased p53 expression. In line with these results, MPL suppressed cellular thymidine incorporation thus impairing DNA synthesis and inducing cleavage of poly (ADP-ribose) polymerase (PARP-1). Combined these pre-clinical findings reveal for the first time the anticancer potential of monepantel.

Background: malignant peritoneal mesothelioma (MPM) is a rare peritoneal mesothelial neoplasm. Ki67 and BCL2 are established prognostic markers in several cancers. High Ki67 expression indicates tumour progression, whilst similar expression of BCL2 retards tumour replication. Traditionally, prognosis in MPM is gauged with a single biomarker assessed separately in a dichotomous manner. Here, we examine prognosis with dual biomarkers incorporated in a model to predict survival., Materials and Methods: Forty two MPM archival patient tumours were screened for Ki67 and BCL2 by immunohistochemistry and evaluated using standard methods. Ki67 and BCL2 expression was incorporated into a prognostic model to develop Ki67-BCL2 index. Using this index, three hazard groups were identified (high, medium and low risk). Kaplan-Meier survival analysis was performed to assess the significance of these hazard groups in the various clinicopathological categories., Results: In all clinicopathological categories, high risk group showed poor prognosis compared to low risk group (p = < 0.001). Compared to medium risk, high risk group carried poor prognosis in all tumours, females, epitheloid tumours, peritoneal cancer index (PCI) < 20, ≥ 20, age at diagnosis (AAD) < 60, and ≥ 60 years. Independent of the Ki67-BCL2 index, male, sarcomatoid, PCI ≥ 20 and AAD ≥ 60 were poor prognostic factors. High risk group was an independent poor prognostic factor in all tumours, males, females and age < 60 years. The distribution of high risk: low risk group in male and female was 3: 2 and 2: 3, respectively, indicating a gender difference. Comparing hazard ratios generated by Ki67-BCL2 index to that of either Ki67 or BCL2, as a single prognostic biomarker, there was a reduction of HR values., Conclusion: Ki67-BCL2 index seems to suggest a more sensitive method of predicting prognosis. However, the current model needs further evaluation in an independent large cohort sample.

Unlabelled: Background Malignant peritoneal mesothelioma (MPM) is a rare neoplasm of the peritoneal membrane that is causally related to asbestos exposure. Survival after treatment is poor. Current therapy involving hyperthermic intraperitoneal chemotherapy has improved survival in selective patients. In the past, several prognostic factors have been identified in MPM patients and this has prompted the development of new therapies and patient management. Since BCL2, an antiapoptotic oncoprotein, is a favourable prognostic factor in breast cancer, we investigated to determine the significance of BCL2 in MPM. Materials and Methods Forty two archival patient tumour sections embedded in paraffin blocks were sectioned and subjected to immunohistochemistry to detect BCL2. The staining intensity and abundance was classified using standard procedures and classified into two groups (0-4 = low & 5-8 = high expression). The distribution of BCL2 groups was examined in the different clinicopathological categories to determine prognosis using Kaplan-Meier survival analysis., Results: Univariate analysis revealed that in almost all clinicopathological categories, high BCL2 expression predisposed patients to a favourable prognosis. Independent of BCL2 expression, univariate analysis also showed that male gender, sarcomatoid histology, high PCI and age at diagnosis ≥ 60 years were associated poor prognosis. Multivariate analysis indicated that for all tumours, males and females, high BCL2 expression was associated with good prognosis. Further, independent of BCL2, age ≥ 60 years is an unfavourable prognostic factor., Conclusion: Expression of BCL2 may serve to distinguish prognosis within the individual clinicopathological categories. BCL2 is also an independent variable in all tumours, males and females, with high expression being associated with good prognosis.

Angiogenesis in the peritoneal cavity arising from ovarian cancer leads to peritoneal carcinomatosis, malignant ascites formation, morbidity and high mortality. Recent studies in our laboratory have shown albendazole (ABZ) to be a potent inhibitor of angiogenesis and malignant ascites formation. The current study was designed to find the pharmacokinetics of the drug and its major metabolites albendazole sulfoxide (ABZSO) and albendazole sulfone (ABZSO(2)) in an experimental model of ovarian cancer. Additionally, we sought to investigate if the cancer-induced changes in the peritoneal cavity would affect the kinetics of ABZ. On this basis, ABZ was administered 150 mg/kg intraperitoneally to groups of mice bearing peritoneal carcinomatosis and also to groups of healthy mice with no tumor. Blood and peritoneal wash samples were collected for up to 72 h. Concentration of ABZ and its metabolites in the samples were analysed by an established high performance liquid chromatography method. In the healthy mice, drug and metabolite concentrations were found to be low to undetectable. On the contrary, tumor-bearing mice had higher levels of ABZSO in both the plasma and their peritoneal wash. This may at least in part be attributed to the high vascular endothelial growth factor levels present in the peritoneal cavity of the diseased mice. The data obtained in this study suggest that peritoneal carcinomatosis changes ABZ absorption from the peritoneal cavity.

Background: Resistance to paclitaxel (PTX) is a major concern in treating ovarian cancer. Thus, agents effective in taxane-resistant tumours are highly sought. It has recently been shown that albendazole (ABZ) is a potent inhibitor of cell proliferation, angiogenesis and tumour growth. This study was designed to examine the efficacy of ABZ in PTX-resistant human ovarian cancer 1A9PTX22 cells., Materials and Methods: Using both the parent PTX-sensitive 1A9 and PTX-resistant sub-line 1A9PTX22 cells, the effects of both drugs on cell proliferation, tubulin polymerisation and microtubule distribution across the cell was investigated., Results: Comparison of the inhibitory concentration to achieve 50% cell death (IC(50)) revealed that, unlike PTX, ABZ is highly efficacious in inhibiting proliferation of 1A9PTX22 cells. The finding that ABZ but not PTX is highly effective in disrupting tubulin polymerisation in these cells confirmed involvement of the tubulin pathway., Conclusion: Data from this study suggest that ABZ is effective in suppressing growth of PTX-resistant ovarian tumour cells.

Background: Despite significant antiproliferative potential, clinical application of 1,25 dihydroxy vitamin D3 [1,25(OH)2VD3] in the treatment of cancer has been hindered due to the development of hypercalcemia. Various derivatives of 1,25(OH)2VD3 have been synthesized to overcome this side-effect. Seocalcitol (EB1089) is a vitamin D analog that has been extensively studied and shown to have profoundly reduced hypercalcemic effects. Here the effects of EB1089 were evaluated in Hep 3B, SKHEP-1, PLC/PRF/5, HTC and Novikoff hepatocellular cancer (HCC) cell lines., Materials and Methods: In vitro, cells were treated with different concentrations of EB1089 (1-1000 nM). Analytical tests were then performed including cell count and 3H thymidine assay. For in vivo analysis, SKHEP-1 cells were xenografted into nude male mice. Twenty-four hours after inoculation, mice were randomly assigned to a control group (n=10) or one of the treatment groups (3 groups of 10 mice) receiving 0.02, 0.1 or 0.5 microg/kg/day of EB1089. Control animals received the vehicle (propylene glycol). To minimize the number of intraperitoneal injections, oral and intraperitoneal routes were used on alternate days. Tumor size was measured every third day and the volumes were estimated using the formula 0.5 x length x (width)2., Results: In vitro: Proliferation of Hep 3B, PLC/PRF/5 and SKHEP-1 HCC cells was significantly inhibited at all EB1089 concentrations tested, while HTC cells only responded to 1000 nM concentration of EB1089. Proliferation of Novikoff cells was unaffected by the drug at all concentrations examined. In vivo: EB1089 effectively inhibited SKHEP-1 tumor growth without inducing hypercalcemia (p<0.05)., Conclusion: Results of the present study indicate that EB1089 is an effective growth inhibitor of HCC tumors.

Background: Over recent years, we have identified a potentially new indication for albendazole (ABZ) namely that of an anticancer agent. Our recent data indicate that besides regional use, the drug is quite likely to be useful as a systemic anticancer agent. However, with extremely low solubility, ABZ has to be prepared in a biocompatible solubilized form before any systemic evaluation is possible. The present study aimed at preparing soluble ABZ and evaluating its in vitro antiproliferative efficacy and toxicity., Experimental Design: Using beta-cyclodextrins (CDs), various formulations of ABZ were prepared and tested in cell culture for antiproliferative efficacy, cell integrity and cell toxicity against human ovarian cancer cell lines 1A9, OVCAR-3 and SKOV-3. Hepatocytes isolated from patients undergoing liver tumor resection were used for toxicity evaluations., Results: Treatment of tumor cells with ABZ-CD + citric acid (CA) solution led to dose-dependent inhibition of cell proliferation. Compared to an ethanolic solution of ABZ, ABZ-CD + CA increased the antiproliferative efficacy of ABZ. Furthermore, in contrast to the ethanolic solution, ABZ-CD-CA complex profoundly (p<0.001) reduced the number of OVCAR-3 colonies formed. Fresh human hepatocytes exposed for 3 days to the highest ABZ concentration used in the study (1 microM), revealed no drug toxicity., Conclusion: Complexation of ABZ with beta-cyclodextrin leads to the formation of an ABZ solution with potent antiproliferative effects. This solution may find clinical value as an intravenous anticancer agent.

Background: Recent studies from our group have shown the potent antitumor effects of albendazole (ABZ). It was hypothesized that intraperitoneal (i.p.) administration of ABZ in peritoneal carcinomatosis (PC) could lead to long exposure of tumor cells to high concentration of the drug and possibly to reduced systemic toxicity., Materials and Methods: Eight male New Zealand white rabbits were randomized into two groups, all given a single dose of ABZ 150 mg/kg suspended in 0.5% carboxymethylcellulose (CMC), either as i.p. injection, or as oral administration. The concentration of ABZ and its metabolites in plasma were determined using a high performance liquid chromatography method., Results: The parent drug was detected in plasma after oral and i.p. administration. The C(max) of albendazole sulphoxide (ABZ-SO) resulted in a much higher plasma concentration in the oral group (41.86 microg/ml) than in the i.p. group (16.84 microg/ml, p < 0.05). The area under the concentration over time curve of ABZ-SO in the oral group (1010.43 microg/ml/h) was also significantly higher than that of the i.p. group (528.33 microg/ml/h, p < 0.05). Compared to oral administration, the i.p. administration of an ABZ suspension led to significantly lower plasma levels of the major metabolite (ABZ-SO). This could have considerable therapeutic benefits in the regional treatment of PC.