XIAP downregulation accompanies mebendazole growth inhibition in melanoma xenografts

Mebendazole targets essential proteins in glucose metabolism leading gastric cancer cells to death

Gastric cancer (GC) is among the most-diagnosed and deadly malignancies worldwide. Deregulation in cellular bioenergetics is a hallmark of cancer. Based on the importance of metabolic reprogramming for the development and cancer progression, inhibitors of cell metabolism have been studied as potential candidates for chemotherapy in oncology. Mebendazole (MBZ), an antihelminthic approved by FDA, has shown antitumoral activity against cancer cell lines. However, its potential in the modulation of tumoral metabolism remains unclear. Results evidenced that the antitumoral and cytotoxic mechanism of MBZ in GC cells is related to the modulation of the mRNA expression of glycolic targets SLC2A1, HK1, GAPDH, and LDHA. Moreover, in silico analysis has shown that these genes are overexpressed in GC samples, and this increase in expression is related to decreased overall survival rates. Molecular docking revealed that MBZ modifies the protein structure of these targets, which may lead to changes in their protein function. In vitro studies also showed that MBZ induces alterations in glucose uptake, LDH's enzymatic activity, and ATP production. Furthermore, MBZ induced morphologic and intracellular alterations typical of the apoptotic cell death pathway. Thus, this data indicated that the cytotoxic mechanism of MBZ is related to an initial modulation of the tumoral metabolism in the GC cell line. Altogether, our results provide more evidence about the antitumoral mechanism of action of MBZ towards GC cells and reveal metabolic reprogramming as a potential area in the discovery of new pharmacological targets for GC chemotherapy.

Repurposing approved non-oncology drugs for cancer therapy: a comprehensive review of mechanisms, efficacy, and clinical prospects

Cancer poses a significant global health challenge, with predictions of increasing prevalence in the coming years due to limited prevention, late diagnosis, and inadequate success with current therapies. In addition, the high cost of new anti-cancer drugs creates barriers in meeting the medical needs of cancer patients, especially in developing countries. The lengthy and costly process of developing novel drugs further hinders drug discovery and clinical implementation. Therefore, there has been a growing interest in repurposing approved drugs for other diseases to address the urgent need for effective cancer treatments. The aim of this comprehensive review is to provide an overview of the potential of approved non-oncology drugs as therapeutic options for cancer treatment. These drugs come from various chemotherapeutic classes, including antimalarials, antibiotics, antivirals, anti-inflammatory drugs, and antifungals, and have demonstrated significant antiproliferative, pro-apoptotic, immunomodulatory, and antimetastatic properties. A systematic review of the literature was conducted to identify relevant studies on the repurposing of approved non-oncology drugs for cancer therapy. Various electronic databases, such as PubMed, Scopus, and Google Scholar, were searched using appropriate keywords. Studies focusing on the therapeutic potential, mechanisms of action, efficacy, and clinical prospects of repurposed drugs in cancer treatment were included in the analysis. The review highlights the promising outcomes of repurposing approved non-oncology drugs for cancer therapy. Drugs belonging to different therapeutic classes have demonstrated notable antitumor effects, including inhibiting cell proliferation, promoting apoptosis, modulating the immune response, and suppressing metastasis. These findings suggest the potential of these repurposed drugs as effective therapeutic approaches in cancer treatment. Repurposing approved non-oncology drugs provides a promising strategy for addressing the urgent need for effective and accessible cancer treatments. The diverse classes of repurposed drugs, with their demonstrated antiproliferative, pro-apoptotic, immunomodulatory, and antimetastatic properties, offer new avenues for cancer therapy. Further research and clinical trials are warranted to explore the full potential of these repurposed drugs and optimize their use in treating various cancer types. Repurposing approved drugs can significantly expedite the process of identifying effective treatments and improve patient outcomes in a cost-effective manner.

Drug Repurposing in Oncology: A Systematic Review of Randomized Controlled Clinical Trials

Quality pharmacological treatment can improve survival in many types of cancer. Drug repurposing offers advantages in comparison with traditional drug development procedures, reducing time and risk. This systematic review identified the most recent randomized controlled clinical trials that focus on drug repurposing in oncology. We found that only a few clinical trials were placebo-controlled or standard-of-care-alone-controlled. Metformin has been studied for potential use in various types of cancer, including prostate, lung, and pancreatic cancer. Other studies assessed the possible use of the antiparasitic agent mebendazole in colorectal cancer and of propranolol in multiple myeloma or, when combined with etodolac, in breast cancer. We were able to identify trials that study the potential use of known antineoplastics in other non-oncological conditions, such as imatinib for severe coronavirus disease in 2019 or a study protocol aiming to assess the possible repurposing of leuprolide for Alzheimer's disease. Major limitations of these clinical trials were the small sample size, the high clinical heterogeneity of the participants regarding the stage of the neoplastic disease, and the lack of accounting for multimorbidity and other baseline clinical characteristics. Drug repurposing possibilities in oncology must be carefully examined with well-designed trials, considering factors that could influence prognosis.

Repurposing of Benzimidazole Anthelmintic Drugs as Cancer Therapeutics

Simple Summary

Although non-prescription anthelmintics are often used for cancer treatment, there is a lack of information regarding their anti-cancer effects in clinical settings. The aims of our review are to describe the possibilities and limitations of the anti-cancer effects of benzimidazole anthelmintics and to suggest ways to overcome these limitations. The results of the current review illustrate the potential development of anthelmintics as a useful strategy for cancer treatment based on much preclinical evidence. Furthermore, they suggest that more rigorous studies on whole anti-cancer pathways and development strategies, including formulations, could result in significantly enhanced anti-cancer effects of benzimidazoles as a repurposed cancer therapy in clinical settings.

Abstract

Benzimidazoles have shown significant promise for repurposing as a cancer therapy. The aims of this review are to investigate the possibilities and limitations of the anti-cancer effects of benzimidazole anthelmintics and to suggest ways to overcome these limitations. This review included studies on the anti-cancer effects of 11 benzimidazoles. Largely divided into three parts, i.e., preclinical anti-cancer effects, clinical anti-cancer effects, and pharmacokinetic properties, we examine the characteristics of each benzimidazole and attempt to elucidate its key properties. Although many studies have demonstrated the anti-cancer effects of benzimidazoles, there is limited evidence regarding their effects in clinical settings. This might be because the clinical trials conducted using benzimidazoles failed to restrict their participants with specific criteria including cancer entities, cancer stages, and genetic characteristics of the participants. In addition, these drugs have limitations including low bioavailability, which results in insufficient plasma concentration levels. Additional studies on whole anti-cancer pathways and development strategies, including formulations, could result significant enhancements of the anti-cancer effects of benzimidazoles in clinical situations.

Targeting the Unwindosome by Mebendazole Is a Vulnerability of Chemoresistant Hepatoblastoma

Resistance to conventional chemotherapy remains a huge challenge in the clinical management of hepatoblastoma, the most common liver tumor in childhood. By integrating the gene expression data of hepatoblastoma patients into the perturbation prediction tool Connectivity Map, we identified the clinical widely used anthelmintic mebendazole as a drug to circumvent chemoresistance in permanent and patient-derived xenograft cell lines that are resistant to cisplatin, the therapeutic backbone of hepatoblastoma treatment. Viability assays clearly indicated a potent reduction of tumor cell growth upon mebendazole treatment in a dose-dependent manner. The combination of mebendazole and cisplatin revealed a strong synergistic effect, which was comparable to the one seen with cisplatin and doxorubicin, the current treatment for high-risk hepatoblastoma patients. Moreover, mebendazole treatment resulted in reduced colony and tumor spheroid formation capabilities, cell cycle arrest, and induction of apoptosis of hepatoblastoma cells. Mechanistically, mebendazole causes blockage of microtubule formation and transcriptional downregulation of genes encoding the unwindosome, which are highly expressed in chemoresistant tumors. Most importantly, mebendazole significantly reduced tumor growth in a subcutaneous xenograft transplantation mouse model without side effects. In conclusion, our results strongly support the clinical use of mebendazole in the treatment of chemoresistant hepatoblastoma and highlight the potential theranostic value of unwindosome-associated genes.

Anticancer potential of mebendazole against chronic myeloid leukemia: in silico and in vitro studies revealed new insights about the mechanism of action

Chronic myeloid leukemia (CML) is caused by constitutively active fusion protein BCR-ABL1, and targeting ABL1 is a promising therapy option. Imatinib, dasatinib, and nilotinib have all been shown to work effectively in clinical trials. ABL1 mutations, particularly the T315I gate-keeper mutation, cause resistance in patients. As a result, broad-spectrum ABL1 medicines are desperately needed. In order to screen potential drugs targeting CML, mebendazole (MBZ) was subjected to the in vitro test against CML cell lines (K562 and FEPS) and computational assays. The antiproliferative effect of MBZ and the combination with tyrosine kinase inhibitors (TKIs) was tested using end-point viability assays, cell cycle distribution analysis, cell membrane, and mitochondrial dyes. By interrupting the cell cycle and causing cell death, MBZ and its combination with imatinib and dasatinib have a significant antiproliferative effect. We identified MBZ as a promising “new use” drug targeting wild-type and mutant ABL1 using molecular docking. Meanwhile, we determined which residues in the allosteric site are important in ABL1 drug development. These findings may not only serve as a model for repositioning current authorized medications but may also provide ABL1-targeted anti-CML treatments a fresh lease of life.

Drug repurposing: An emerging strategy in alleviating skin cancer

Skin cancer is one of the most common forms of cancer. Several million people are estimated to have affected with this condition worldwide. Skin cancer generally includes melanoma and non-melanoma with the former being the most dangerous. Chemotherapy has been one of the key therapeutic strategies employed in the treatment of skin cancer, especially in advanced stages of the disease. It could be also used as an adjuvant with other treatment modalities depending on the type of skin cancer. However, there are several shortfalls associated with the use of chemotherapy such as non-selectivity, tumour resistance, life-threatening toxicities, and the exorbitant cost of medicines. Furthermore, new drug discovery is a lengthy and costly process with minimal likelihood of success. Thus, drug repurposing (DR) has emerged as a new avenue where the drug approved formerly for the treatment of one disease can be used for the treatment of another disease like cancer. This approach is greatly beneficial over the de novo approach in terms of time and cost. Moreover, there is minimal risk of failure of repurposed therapeutics in clinical trials. There are a considerable number of studies that have reported on drugs repurposed for the treatment of skin cancer. Thus, the present manuscript offers a comprehensive overview of drugs that have been investigated as repurposing candidates for the efficient treatment of skin cancers mainly melanoma and its oncogenic subtypes, and non-melanoma. The prospects of repurposing phytochemicals against skin cancer are also discussed. Furthermore, repurposed drug delivery via topical route and repurposed drugs in clinical trials are briefed. Based on the findings from the reported studies discussed in this manuscript, drug repurposing emerges to be a promising approach and thus is expected to offer efficient treatment at a reasonable cost in devitalizing skin cancer.

Double Repositioning: Veterinary Antiparasitic to Human Anticancer

Drug repositioning, the approach of discovering different uses for existing drugs, has gained enormous popularity in recent years in the anticancer drug discovery field due to the increasing demand for anticancer drugs. Additionally, the repurposing of veterinary antiparasitic drugs for the treatment of cancer is gaining traction, as supported by existing literature. A prominent example is the proposal to implement the use of veterinary antiparasitics such as benzimidazole carbamates and halogenated salicylanilides as novel anticancer drugs. These agents have revealed pronounced anti-tumor activities and gained special attention for “double repositioning”, as they are repurposed for different species and diseases simultaneously, acting via different mechanisms depending on their target. As anticancer agents, these compounds employ several mechanisms, including the inhibition of oncogenic signal transduction pathways of mitochondrial respiration and the inhibition of cellular stress responses. In this review, we summarize and provide valuable information about the experimental, preclinical, and clinical trials of veterinary antiparasitic drugs available for the treatment of various cancers in humans. This review suggests the possibility of new treatment options that could improve the quality of life and outcomes for cancer patients in comparison to the currently used treatments.

Antiparasitic mebendazole (MBZ) effectively overcomes cisplatin resistance in human ovarian cancer cells by inhibiting multiple cancer-associated signaling pathways

Ovarian cancer is the third most common cancer and the second most common cause of gynecologic cancer death in women. Its routine clinical management includes surgical resection and systemic therapy with chemotherapeutics. While the first-line systemic therapy requires the combined use of platinum-based agents and paclitaxel, many ovarian cancer patients have recurrence and eventually succumb to chemoresistance. Thus, it is imperative to develop new strategies to overcome recurrence and chemoresistance of ovarian cancer. Repurposing previously-approved drugs is a cost-effective strategy for cancer drug discovery. The antiparasitic drug mebendazole (MBZ) is one of the most promising drugs with repurposing potential. Here, we investigate whether MBZ can overcome cisplatin resistance and sensitize chemoresistant ovarian cancer cells to cisplatin. We first established and characterized two stable and robust cisplatin-resistant (CR) human ovarian cancer lines and demonstrated that MBZ markedly inhibited cell proliferation, suppressed cell wounding healing/migration, and induced apoptosis in both parental and CR cells at low micromole range. Mechanistically, MBZ was revealed to inhibit multiple cancer-related signal pathways including ELK/SRF, NFKB, MYC/MAX, and E2F/DP1 in cisplatin-resistant ovarian cancer cells. We further showed that MBZ synergized with cisplatin to suppress cell proliferation, induce cell apoptosis, and blunt tumor growth in xenograft tumor model of human cisplatin-resistant ovarian cancer cells. Collectively, our findings suggest that MBZ may be repurposed as a synergistic sensitizer of cisplatin in treating chemoresistant human ovarian cancer, which warrants further clinical studies.

Mebendazole disrupts stromal desmoplasia and tumorigenesis in two models of pancreatic cancer

The five-year survival rate for metastatic pancreatic cancer is currently only 3%, which increases to 13% with local invasion only and to 39% with localized disease at diagnosis. Here we evaluated repurposed mebendazole, an approved anthelminthic drug, to determine how mebendazole might work at the different stages of pancreatic cancer formation and progression. We asked if mebendazole could prevent initiation of pancreatic intraepithelial neoplasia precursor lesions, interfere with stromal desmoplasia, or suppress tumor growth and liver metastasis. In both the Kras ^LSL.G12D/+; Pdx1-Cre (KC) mouse model of caerulein-induced inflammatory pancreatitis and the Kras ^LSL.G12D/+; Tp53 ^R172H/+; Pdx1-Cre (KPC) mouse model of advanced pancreatic cancer, mebendazole significantly reduced pancreas weight, dysplasia and intraepithelial neoplasia formation, compared to controls. Mebendazole significantly reduced trichrome-positive fibrotic connective tissue and α-SMA-positive activated pancreatic stellate cells that heralds fibrogenesis. In the aggressive KPC model, mebendazole significantly suppressed pancreatic tumor growth, both as an early and late intervention. Mebendazole reduced the overall incidence of pancreatic cancer and severity of liver metastasis in KPC mice. Using early models of pancreatic cancer, treatment with mebendazole resulted in less inflammation, decreased dysplasia, with the later stage model additionally showing a decreased tumor burden, less advanced tumors, and a reduction of metastasis. We conclude that mebendazole should be investigated further as a component of adjuvant therapy to slow progression and prevent metastasis, and well as for primary prevention in the highest risk patients.

A phase 2a clinical study on the safety and efficacy of individualized dosed mebendazole in patients with advanced gastrointestinal cancer

Mebendazole is used extensively for treatment of local gut helminthic and invasive echinococcus infections. Anticancer effects of mebendazole have been shown in experimental cancer models and in case studies in patients with advanced cancer. Given these observations, the aims of this study were to investigate safety and efficacy of individualized dosed mebendazole in the cancer indication. Patients with treatment refractory gastrointestinal cancer were treated with individualized dose adjusted mebendazole up to 4 g/day to target a serum concentration of 300 ng/ml. Efficacy and safety were assessed by CT-scans, clinical surveillance and blood sampling. Eleven patients were included in the study and 10 started the treatment phase. Two patients stopped treatment prior to and the remaining eight after tumour evaluation by CT-scan at 8 weeks, all due to progressive disease. Four patients also fulfilled criteria suggested for hyperprogression. Only five patients reached the target serum-mebendazole concentration. No severe adverse effects were observed. Individualized dose adjusted mebendazole is safe and well tolerated in patients with advanced cancer but all patients experienced rapid progressive disease. New approaches such as prodrug development and combination with other anticancer drugs seem needed for further exploration of mebendazole as an anticancer drug.

Repurposing of Drug Candidates for Treatment of Skin Cancer

Skin cancers are highly prevalent malignancies that affect millions of people worldwide. These include melanomas and nonmelanoma skin cancers. Melanomas are among the most dangerous cancers, while nonmelanoma skin cancers generally exhibit a more benign clinical pattern; however, they may sometimes be aggressive and metastatic. Melanomas typically appear in body regions exposed to the sun, although they may also appear in areas that do not usually get sun exposure. Thus, their development is multifactorial, comprising endogenous and exogenous risk factors. The management of skin cancer depends on the type; it is usually based on surgery, chemotherapy, immunotherapy, and targeted therapy. In this respect, oncological treatments have demonstrated some progress in the last years; however, current therapies still present various disadvantages such as little cell specificity, recurrent relapses, high toxicity, and increased costs. Furthermore, the pursuit of novel medications is expensive, and the authorization for their clinical utilization may take 10–15 years. Thus, repositioning of drugs previously approved and utilized for other diseases has emerged as an excellent alternative. In this mini-review, we aimed to provide an updated overview of drugs’ repurposing to treat skin cancer and discuss future perspectives.

Mebendazole and temozolomide in patients with newly diagnosed high-grade gliomas: results of a phase 1 clinical trial

Background

Mebendazole is an anthelmintic drug introduced for human use in 1971 that extends survival in preclinical models of glioblastoma and other brain cancers.

Methods

A single-center dose-escalation and safety study of mebendazole in 24 patients with newly diagnosed high-grade gliomas in combination with temozolomide was conducted. Patients received mebendazole in combination with adjuvant temozolomide after completing concurrent radiation plus temozolomide. Dose-escalation levels were 25, 50, 100, and 200 mg/kg/day of oral mebendazole. A total of 15 patients were enrolled at the highest dose studied of 200 mg/kg/day. Trough plasma levels of mebendazole were measured at 4, 8, and 16 weeks.

Results

Twenty-four patients (18 glioblastoma and 6 anaplastic glioma) were enrolled with a median age of 49.8 years. Four patients (at 200 mg/kg) developed elevated grade 3 alanine aminotransferase (ALT) and/or aspartate transaminase (AST) after 1 month, which reversed with lower dosing or discontinuation. Plasma levels of mebendazole were variable but generally increased with dose. Kaplan–Meier analysis showed a 21-month median overall survival with 41.7% of patients alive at 2 years and 25% at 3 and 4 years. Median progression-free survival (PFS) from the date of diagnosis for 17 patients taking more than 1 month of mebendazole was 13.1 months (95% confidence interval [CI]: 8.8–14.6 months) but for 7 patients who received less than 1 month of mebendazole PFS was 9.2 months (95% CI: 5.8–13.0 months).

Conclusion

Mebendazole at doses up to 200 mg/kg demonstrated long-term safety and acceptable toxicity. Further studies are needed to determine mebendazole’s efficacy in patients with malignant glioma.

The Antihelminthic Drug, Mebendazole, Induces Apoptosis in Adult T-Cell Leukemia/Lymphoma Cancer Cells: In-Vitro Trial

Background: Adult T-cell leukemia/lymphoma (ATLL) is a poor prognostic Hematopoietic malignancy with various therapeutic challenges, which had been classified as non-Hodgkin lymphoma. The Drug switching, as a novel, innovative and promising approach, is an opportunity to overcoming on therapeutic challenges of hard-treating disease, e.g. ATLL. Our aim is evaluating the antiproliferative and apoptotic effect of Mebendazole (MBZ) on ATLL cancer cells in in-vitro conditions.

Materials and Methods: We used Jurkat cell-line as ATLL cancer cells. After treatment of MBZ in different concentrations on jurkat cells, the cell viabilities were determined by MTT assay. After IC₅₀ value determination, the 24-, 48- and 72-h treatments had been performed in IC₅₀ concentration and control to evaluating the quantitative apoptosis rate by Annexin/PI Flowcytometry and qualitative apoptosis by DAPI Nuclear staining. Also, Glucose spectrophotometry were performed to evaluate the reduced amount of glucose uptake through MBZ treatment.

Results: MBZ inhibits proliferation of jurkat cells and IC₅₀ value had been estimated 10 μM (P< 0.01). According to the flowcytometric results, increasing in drug concentration is associated with decrease cell viability and the percentage of full-apoptosis. However, it inversely correlates with percentage of early-apoptosis rate. Also, the microscopic captures of DAPI Nuclear staining confirms the flowcytometry results in qualitative manner. In addition, it was found that inhibition of glucose uptake was inversely correlated with increased MBZ concentration (P< 0.05).

Conclusion: MBZ potentially inhibits the proliferation of ATLL cancer cells in in-vitro condition. MBZ inhibits the growth of Jurkat cells by inducing apoptosis. Also, we suggest that indirectly inhibition of Glucose transporting occurs by MBZ, which could induce apoptosis in cancer cells.

Mebendazole is unique among tubulin-active drugs in activating the MEK-ERK pathway

We recently showed that the anti-helminthic compound mebendazole (MBZ) has immunomodulating activity in monocyte/macrophage models and induces ERK signalling. In the present study we investigated whether MBZ induced ERK activation is shared by other tubulin binding agents (TBAs) and if it is observable also in other human cell types. Curated gene signatures for a panel of TBAs in the LINCS Connectivity Map (CMap) database showed a unique strong negative correlation of MBZ with MEK/ERK inhibitors indicating ERK activation also in non-haematological cell lines. L1000 gene expression signatures for MBZ treated THP-1 monocytes also connected negatively to MEK inhibitors. MEK/ERK phosphoprotein activity testing of a number of TBAs showed that only MBZ increased the activity in both THP-1 monocytes and PMA differentiated macrophages. Distal effects on ERK phosphorylation of the substrate P90RSK and release of IL1B followed the same pattern. The effect of MBZ on MEK/ERK phosphorylation was inhibited by RAF/MEK/ERK inhibitors in THP-1 models, CD3/IL2 stimulated PBMCs and a MAPK reporter HEK-293 cell line. MBZ was also shown to increase ERK activity in CD4+ T-cells from lupus patients with known defective ERK signalling. Given these mechanistic features MBZ is suggested suitable for treatment of diseases characterized by defective ERK signalling, notably difficult to treat autoimmune diseases.

The Antitumor Potentials of Benzimidazole Anthelmintics as Repurposing Drugs

The development of refractory tumor cells limits therapeutic efficacy in cancer by activating mechanisms that promote cellular proliferation, migration, invasion, metastasis, and survival. Benzimidazole anthelmintics have broad-spectrum action to remove parasites both in human and veterinary medicine. In addition to being antiparasitic agents, benzimidazole anthelmintics are known to exert anticancer activities, such as the disruption of microtubule polymerization, the induction of apoptosis, cell cycle (G2/M) arrest, anti-angiogenesis, and blockage of glucose transport. These antitumorigenic effects even extend to cancer cells resistant to approved therapies and when in combination with conventional therapeutics, enhance anticancer efficacy and hold promise as adjuvants. Above all, these anthelmintics may offer a broad, safe spectrum to treat cancer, as demonstrated by their long history of use as antiparasitic agents. The present review summarizes central literature regarding the anticancer effects of benzimidazole anthelmintics, including albendazole, parbendazole, fenbendazole, mebendazole, oxibendazole, oxfendazole, ricobendazole, and flubendazole in cancer cell lines, animal tumor models, and clinical trials. This review provides valuable information on how to improve the quality of life in patients with cancers by increasing the treatment options and decreasing side effects from conventional therapy.

Mebendazole is a potent inhibitor to chemoresistant T cell acute lymphoblastic leukemia cells

Mebendazole (MBZ) is a tubulin-suppressive antihelmintic agent with low toxicity, which has been repurposed to treat different types of tumors. Chemoresistance is quite common in refractory or relapsed T cell acute lymphoblastic leukemia (T-ALL), which leads to dismal chances of recovery. In this study, MBZ was found to suppress the proliferation and reduce the viability of T-ALL cell line, CCRF-CEM, and its chemoresistant derivative, CEM/C1, at nanomolar concentrations. The inhibitive effects were found to be dose-dependent and not to be affected by the chemoresistance of CEM/C1 cells. Cell cycle arrest, caspase 3/7 activation and tubulin disruption were found in the MBZ-treated T-ALL cells. Notch1 signaling, which is often aberrantly activated in T-ALL cells, was showed to be suppressed by MBZ treatments. MBZ administration in murine T-ALL models also suppressed the growth of CEM/C1 cells, indicating that MBZ may be developed as a therapeutic agent for chemoresistant T-ALLs. The mRNA levels of the Notch1 and Hes1 were also confirmed to be suppressed by MBZ in vivo, which was consistent with the in vitro observations. This study demonstrated, for the first time, that MBZ could inhibit chemoresistant T-ALL cells both in vitro and in vivo, and the Notch1 signaling pathway was suppressed by MBZ treatment.

New drugs are not enough‑drug repositioning in oncology: An update

Drug repositioning refers to the concept of discovering novel clinical benefits of drugs that are already known for use treating other diseases. The advantages of this are that several important drug characteristics are already established (including efficacy, pharmacokinetics, pharmacodynamics and toxicity), making the process of research for a putative drug quicker and less costly. Drug repositioning in oncology has received extensive focus. The present review summarizes the most prominent examples of drug repositioning for the treatment of cancer, taking into consideration their primary use, proposed anticancer mechanisms and current development status.

Repurposing screen identifies mebendazole as a clinical candidate to synergise with docetaxel for prostate cancer treatment

BACKGROUND

Docetaxel chemotherapy in prostate cancer has a modest impact on survival. To date, efforts to develop combination therapies have not translated into new treatments. We sought to develop a novel therapeutic strategy to tackle chemoresistant prostate cancer by enhancing the efficacy of docetaxel.

METHODS

We performed a drug-repurposing screen by using murine-derived prostate cancer cell lines driven by clinically relevant genotypes. Cells were treated with docetaxel alone, or in combination with drugs (n = 857) from repurposing libraries, with cytotoxicity quantified using High Content Imaging Analysis.

RESULTS

Mebendazole (an anthelmintic drug that inhibits microtubule assembly) was selected as the lead drug and shown to potently synergise docetaxel-mediated cell killing in vitro and in vivo. Dual targeting of the microtubule structure was associated with increased G2/M mitotic block and enhanced cell death. Strikingly, following combined docetaxel and mebendazole treatment, no cells divided correctly, forming multipolar spindles that resulted in aneuploid daughter cells. Liposomes entrapping docetaxel and mebendazole suppressed in vivo prostate tumour growth and extended progression-free survival.

CONCLUSIONS

Docetaxel and mebendazole target distinct aspects of the microtubule dynamics, leading to increased apoptosis and reduced tumour growth. Our data support a new concept of combined mebendazole/docetaxel treatment that warrants further clinical evaluation.

Mebendazole as a Candidate for Drug Repurposing in Oncology: An Extensive Review of Current Literature

Anticancer treatment efficacy is limited by the development of refractory tumor cells characterized by increased expression and activity of mechanisms promoting survival, proliferation, and metastatic spread. The present review summarizes the current literature regarding the use of the anthelmintic mebendazole (MBZ) as a repurposed drug in oncology with a focus on cells resistant to approved therapies, including so called “cancer stem cells”. Mebendazole meets many of the characteristics desirable for a repurposed drug: good and proven toxicity profile, pharmacokinetics allowing to reach therapeutic concentrations at disease site, ease of administration and low price. Several in vitro studies suggest that MBZ inhibits a wide range of factors involved in tumor progression such as tubulin polymerization, angiogenesis, pro-survival pathways, matrix metalloproteinases, and multi-drug resistance protein transporters. Mebendazole not only exhibits direct cytotoxic activity, but also synergizes with ionizing radiations and different chemotherapeutic agents and stimulates antitumoral immune response. In vivo, MBZ treatment as a single agent or in combination with chemotherapy led to the reduction or complete arrest of tumor growth, marked decrease of metastatic spread, and improvement of survival. Further investigations are warranted to confirm the clinical anti-neoplastic activity of MBZ and its safety in combination with other drugs in a clinical setting.

Mebendazole-induced M1 polarisation of THP-1 macrophages may involve DYRK1B inhibition

OBJECTIVE

We recently showed that the anti-helminthic compound mebendazole (MBZ) has immunomodulating activity by inducing a M2 to M1 phenotype switch in monocyte/macrophage models. In the present study we investigated the potential role of protein kinases in mediating this effect.

RESULTS

MBZ potently binds and inhibits Dual specificity tyrosine-phosphorylation-regulated kinase 1B (DYRK1B) with a Kd and an IC50 of 7 and 360 nM, respectively. The specific DYRK1B inhibitor AZ191 did not mimic the cytokine release profile of MBZ in untreated THP-1 monocytes. However, in THP-1 cells differentiated into macrophages, AZ191 strongly induced a pro-inflammatory cytokine release pattern similar to MBZ and LPS/IFNγ. Furthermore, like MBZ, AZ191 increased the expression of the M1 marker CD80 and decreased the M2 marker CD163 in THP-1 macrophages. In this model, AZ191 also increased phospho-ERK activity although to a lesser extent compared to MBZ. Taken together, the results demonstrate that DYRK1B inhibition could, at least partly, recapitulate immune responses induced by MBZ. Hence, DYRK1B inhibition induced by MBZ may be part of the mechanism of action to switch M2 to M1 macrophages.

Flubendazole and mebendazole impair migration and epithelial to mesenchymal transition in oral cell lines

Benzimidazole anthelmintics flubendazole and mebendazole are microtubule-targeting drugs that showed considerable anti-cancer activity in different preclinical models. In this study, the effects of flubendazole and mebendazole on proliferation, migration and cadherin switching were studied in a panel of oral cell lines in vitro. Both compounds reduced the viability of the PE/CA-PJ15 and H376 oral squamous carcinoma cells and of the premalignant oral keratinocytes DOK with the IC₅₀ values in the range of 0.19-0.26 μM. Normal oral keratinocytes and normal gingival fibroblasts were less sensitive to the treatment. Flubendazole and mebendazole also reduced the migration of the PE/CA-PJ15 cell in concentrations that had no anti-migratory effects on the normal gingival fibroblasts. Levels of the focal adhesion kinase FAK, Rho-A and Rac1 GTPases and the Rho guanine nucleotide exchange factor GEF-H1 were decreased in both PE/CA-PJ15 cells and gingival fibroblasts following treatment. Both drugs also interfered with cadherin switching in the model of TGF-β-induced epithelial to mesenchymal transition (EMT) in the DOK cell line. Levels of N-cadherin were reduced in the TGF-β induced cells co-treated with flubendazol and mebendazole in very low concentration (50 nM). These results suggest direct effects of both benzimidazoles on selected processes of EMT in oral cell lines such as cadherin switching as well as cellular migration.

Mebendazole stimulates CD14+ myeloid cells to enhance T-cell activation and tumour cell killing

Mebendazole (MBZ) was recently shown to induce a tumor suppressive M1 phenotype in THP-1 monocytes and macrophages. In the present study the immune effects of MBZ was further investigated using human peripheral blood mononuclear cells (PBMCs) co-cultured with tumour cells. The Biomap platform was used to screen for biomarkers induced from MBZ exposed co-cultures of T-cell receptor activated PBMCs, HT29 colon cancer cells and either human fibroblasts or human umbilical vein endothelial cells (HUVEC) cells. In these co-culture systems MBZ at 0.3-10 μM induced significant increases in TNFα and IFNγ indicating immune stimulation. PBMC cultures alone were subsequently tested for activation status and only in PBMCs activated by CD3/IL2 stimulation and MBZ, at a clinically achievable concentration, was able to increase PBMC clustering and release of pro-inflammatory IFNγ, TNFα, IL6 and IL1β cytokines. Moreover, when PBMC cultures were functionally tested for immune cell killing of lung cancer A549NucLightRed cells, MBZ significantly increased tumour cell apoptosis and reduced the number of surviving tumour cells. This effect was dependent on the presence of CD14 monocytes/macrophages in the co-culture. In summary, MBZ potentiated the immune stimulatory and anticancer effects of anti-CD3/IL2 activated PBMCs which could be relevant to explain the anticancer activity of MBZ observed in the clinic.

Flubendazole induces mitotic catastrophe and apoptosis in melanoma cells

Flubendazole (FLU) is a widely used anthelmintic drug belonging to benzimidazole group. Recently, several studies have been published demonstrating its potential to inhibit growth of various tumor cells including those derived from colorectal cancer, breast cancer or leukemia via several mechanisms. In the present study we have investigated cytotoxic effects of FLU on malignant melanoma using A-375, BOWES and RPMI-7951 cell lines representing diverse melanoma molecular types. In all three cell lines, FLU inhibited cell growth and proliferation and disrupted microtubule structure and function which was accompanied by dramatic changes in cellular morphology. In addition, FLU-treated cells accumulated at the G2/M phase of cell cycle and displayed the features of mitotic catastrophe characterized by formation of giant cells with multiple nuclei, abnormal spindles and subsequent apoptotic demise. Although this endpoint was observed in all treated melanoma lines, our analyses showed different activated biochemical signaling in particular cells, thus suggesting a promising treatment potential of FLU in malignant melanoma warranting its further testing.

The repurposed anthelmintic mebendazole in combination with trametinib suppresses refractory NRASQ61K melanoma

Structure-based drug repositioning in addition to random chemical screening is now a viable route to rapid drug development. Proteochemometric computational methods coupled with kinase assays showed that mebendazole (MBZ) binds and inhibits kinases important in cancer, especially both BRAF^WT and BRAF^V600E. We find that MBZ synergizes with the MEK inhibitor trametinib to inhibit growth of BRAF^WT-NRAS^Q61K melanoma cells in culture and in xenografts, and markedly decreased MEK and ERK phosphorylation. Reverse Phase Protein Array (RPPA) and immunoblot analyses show that both trametinib and MBZ inhibit the MAPK pathway, and cluster analysis revealed a protein cluster showing strong MBZ+trametinib - inhibited phosphorylation of MEK and ERK within 10 minutes, and its direct and indirect downstream targets related to stress response and translation, including ElK1 and RSKs within 30 minutes. Downstream ERK targets for cell cycle, including cMYC, were down-regulated, consistent with S- phase suppression by MBZ+trametinib, while apoptosis markers, including cleaved caspase-3, cleaved PARP and a sub-G1 population, were all increased with time. These data suggest that MBZ, a well-tolerated off-patent approved drug, should be considered as a therapeutic option in combination with trametinib, for patients with NRAS^Q61mut or other non-V600E BRAF mutant melanomas.

Drug repurposing in cancer

Cancer is a major health issue worldwide, and the global burden of cancer is expected to increase in the coming years. Whereas the limited success with current therapies has driven huge investments into drug development, the average number of FDA approvals per year has declined since the 1990s. This unmet need for more effective anti-cancer drugs has sparked a growing interest for drug repurposing, i.e. using drugs already approved for other indications to treat cancer. As such, data both from pre-clinical experiments, clinical trials and observational studies have demonstrated anti-tumor efficacy for compounds within a wide range of drug classes other than cancer. Whereas some of them induce cancer cell death or suppress various aspects of cancer cell behavior in established tumors, others may prevent cancer development. Here, we provide an overview of promising candidates for drug repurposing in cancer, as well as studies describing the biological mechanisms underlying their anti-neoplastic effects.

The anticancer effect of mebendazole may be due to M1 monocyte/macrophage activation via ERK1/2 and TLR8-dependent inflammasome activation

Mebendazole (MBZ), a drug commonly used for helminitic infections, has recently gained substantial attention as a repositioning candidate for cancer treatment. However, the mechanism of action behind its anticancer activity remains unclear. To address this problem, we took advantage of the curated MBZ-induced gene expression signatures in the LINCS Connectivity Map (CMap) database. The analysis revealed strong negative correlation with MEK/ERK1/2 inhibitors. Moreover, several of the most upregulated genes in response to MBZ exposure were related to monocyte/macrophage activation. The MBZ-induced gene expression signature in the promyeloblastic HL-60 cell line was strongly enriched in genes involved in monocyte/macrophage pro-inflammatory (M1) activation. This was subsequently validated using MBZ-treated THP-1 monocytoid cells that demonstrated gene expression, surface markers and cytokine release characteristic of the M1 phenotype. At high concentrations MBZ substantially induced the release of IL-1β and this was further potentiated by lipopolysaccharide (LPS). At low MBZ concentrations, cotreatment with LPS was required for MBZ-stimulated IL-1β secretion to occur. Furthermore, we show that the activation of protein kinase C, ERK1/2 and NF-kappaB were required for MBZ-induced IL-1β release. MBZ-induced IL-1β release was found to be dependent on NLRP3 inflammasome activation and to involve TLR8 stimulation. Finally, MBZ induced tumor-suppressive effects in a coculture model with differentiated THP-1 macrophages and HT29 colon cancer cells. In summary, we report that MBZ induced a pro-inflammatory (M1) phenotype of monocytoid cells, which may, at least partly, explain MBZ's anticancer activity observed in animal tumor models and in the clinic.

Anthelmintic Flubendazole and Its Potential Use in Anticancer Therapy

Flubendazole is a widely used anthelmintic drug belonging to benzimidazole group. The molecular mechanism of action of flubendazole is based on its specific binding to tubulin, which results in disruption of microtubule structure and function, and in the interference with the microtubule-mediated transport of secretory vesicles in absorptive tissues of helminths. The microtubule-disrupting properties of benzimidazole derivatives raised recently interest in these compounds as possible anti-cancer agents. In this minireview flubendazole effects towards selected human malignant cells including myeloma, leukemia, neuroblastoma, breast cancer, colorectal cancer and melanoma are discussed along with basic data on its pharmacokinetics, metabolism and toxicity.

Effect of matrine combined with cisplatin on the expression of XIAP in human rhabdomyosarcoma RD cells

The combined effects of matrine (Mat) and cisplatin on the survival and apoptosis of rhabdomyosarcoma (RMS) RD cells, as well as the possible mechanism of the synergistic effect of Mat and cisplatin were investigated in the present study. RMS RD cells were divided and treated as follows: control group, 5 mg/l cisplatin group, Mat groups (0.5, 1.0 and 1.5 g/l), and Mat (0.5, 1.0 and 1.5 g/l) combined with 5 mg/l cisplatin groups. An MTT assay and flow cytometry were applied to detect the survival and apoptotic rates, respectively, while RT-PCR was applied to detect the expression levels of X-linked inhibitor of apoptosis protein (XIAP) mRNA in the RD cells of each group. The survival rates of RD cells in each experimental group were lower than in the control group, and the apoptotic rates were higher than those in the control group (P<0.05). An increase in drug concentrations led to the cell proliferation inhibitory and apoptotic rates of the single Mat groups increasing as a function of dose (pairwise comparison among the groups, P<0.05), while the proliferation inhibitory and apoptotic rates of Mat combined with the cisplatin groups under different concentration were significantly higher than those of the single Mat and single cisplatin groups under the same concentration (P<0.01). The expression levels of XIAP mRNA in the RD cells of each experimental group were lower than those in the control group (P<0.05). Additionally, the expression levels of XIAP mRNA in the group treated with Mat and cisplatin were significantly lower than those of the single cisplatin and single Mat groups (P<0.01). In conclusion, Mat and cisplatin are capable of inhibiting the proliferation of RD cells and inducing apoptosis by suppressing the XIAP mRNA expression levels.

Repositioning of drugs for intervention in tumor progression and metastasis: Old drugs for new targets

The increasing unraveling of the molecular basis of cancer offers manifold novel options for intervention strategies. However, the discovery and development of new drugs for potential clinical applications is a tremendously time-consuming and costly process. Translating a novel lead candidate compound into an approved clinical drug takes often more than a decade, and the success rate is very low due to versatile efforts including defining its pharmacokinetics, pharmacodynamics, side effects as well as lack of sufficient efficacy. Thus, strategies are needed to minimize time and costs, while maximizing success rates. A very attractive strategy for novel cancer therapeutic options is the repositioning of already approved drugs. These medicines, approved for the treatment of non-malignant disorders, have already passed some early costs and time, have been tested in humans and are ready for clinical trials as anti-cancer drugs. Here we discuss the repositioning of nonsteroidal anti-inflammatory drugs (NSAID), statins, anti-psychotic drugs, anti-helminthic drugs and vitamin D as anti-tumor agents. We focus on their novel actions and potential for inhibition of cancer growth and metastasis by interfering with target molecules and pathways, which drive these malignant processes. Furthermore, important pre-clinical and clinical data are reviewed herein, which elucidate their therapeutic mechanisms which enable their repositioning for cancer therapy and disruption of metastasis.

Repurposing Drugs in Oncology (ReDO)-diclofenac as an anti-cancer agent

Diclofenac (DCF) is a well-known and widely used non-steroidal anti-inflammatory drug (NSAID), with a range of actions which are of interest in an oncological context. While there has long been an interest in the use of NSAIDs in chemoprevention, there is now emerging evidence that such drugs may have activity in a treatment setting. DCF, which is a potent inhibitor of COX-2 and prostaglandin E2 synthesis, displays a range of effects on the immune system, the angiogenic cascade, chemo- and radio-sensitivity and tumour metabolism. Both pre-clinical and clinical evidence of these effects, in multiple cancer types, is assessed and summarised and relevant mechanisms of action outlined. Based on this evidence the case is made for further clinical investigation of the anticancer effects of DCF, particularly in combination with other agents - with a range of possible multi-drug and multi-modality combinations outlined in the supplementary materials accompanying the main paper.

Repurposing Drugs in Oncology (ReDO)-nitroglycerin as an anti-cancer agent

Nitroglycerin (NTG), a drug that has been in clinical use for more than a century, has a range of actions which make it of particular interest in an oncological setting. It is generally accepted that the main mechanism of action of NTG is via the production of nitric oxide (NO), which improves cardiac oxygenation via multiple mechanisms including improved blood flow (vasodilation), decreased platelet aggregation, increased erythrocyte O2 release and decreased mitochondrial utilization of oxygen. Its vasoactive properties mean that it has the potential to exploit more fully the enhanced permeability and retention effect in delivering anti-cancer drugs to tumour tissues. Moreover NTG can reduce HIF-1α levels in hypoxic tumour tissues and this may have anti-angiogenic, pro-apoptotic and anti-efflux effects. Additionally NTG may enhance anti-tumour immunity. Pre-clinical and clinical data on these anti-cancer properties of NTG are summarised and discussed. While there is evidence of a positive action as a monotherapy in prostate cancer, there are mixed results in NSCLC where initially positive results have yet to be fully replicated. Based on the evidence presented, a case is made that further exploration of the clinical benefits that may accrue to cancer patients is warranted. Additionally, it is proposed that NTG may synergise with a number of other drugs, including other repurposed drugs, and these are discussed in the supplementary material appended to this paper.

Repurposing Drugs in Oncology (ReDO)-itraconazole as an anti-cancer agent

Itraconazole, a common triazole anti-fungal drug in widespread clinical use, has evidence of clinical activity that is of interest in oncology. There is evidence that at the clinically relevant doses, itraconazole has potent anti-angiogenic activity, and that it can inhibit the Hedgehog signalling pathway and may also induce autophagic growth arrest. The evidence for these anticancer effects, in vitro, in vivo, and clinical are summarised, and the putative mechanisms of their action outlined. Clinical trials have shown that patients with prostate, lung, and basal cell carcinoma have benefited from treatment with itraconazole, and there are additional reports of activity in leukaemia, ovarian, breast, and pancreatic cancers. Given the evidence presented, a case is made that itraconazole warrants further clinical investigation as an anti- cancer agent. Additionally, based on the properties summarised previously, it is proposed that itraconazole may synergise with a range of other drugs to enhance the anti-cancer effect, and some of these possible combinations are presented in the supplementary materials accompanying this paper.

Brain Penetration and Efficacy of Different Mebendazole Polymorphs in a Mouse Brain Tumor Model

PURPOSE

Mebendazole (MBZ), first used as an antiparasitic drug, shows preclinical efficacy in models of glioblastoma and medulloblastoma. Three different mebendazole polymorphs (A, B, and C) exist, and a detailed assessment of the brain penetration, pharmacokinetics, and antitumor properties of each individual mebendazole polymorph is necessary to improve mebendazole-based brain cancer therapy.

EXPERIMENTAL DESIGN AND RESULTS

In this study, various marketed and custom-formulated mebendazole tablets were analyzed for their polymorph content by IR spectroscopy and subsequently tested in an orthotopic GL261 mouse glioma model for efficacy and tolerability. The pharmacokinetics and brain concentration of mebendazole polymorphs and two main metabolites were analyzed by LC/MS. We found that polymorph B and C both increased survival in a GL261 glioma model, as B exhibited greater toxicity. Polymorph A showed no benefit. Polymorph B and C both reached concentrations in the brain that exceeded the IC₅₀ in GL261 cells 29-fold. In addition, polymorph C demonstrated an AUC₀₋₂₄h brain-to-plasma (B/P) ratio of 0.82, whereas B showed higher plasma AUC and lower B/P ratio. In contrast, polymorph A presented markedly lower levels in the plasma and brain. Furthermore, the combination with elacridar was able to significantly improve the efficacy of polymorph C in GL261 glioma and D425 medulloblastoma models in mice.

CONCLUSIONS

Among mebendazole polymorphs, C reaches therapeutically effective concentrations in the brain tissue and tumor with fewer side effects, and is the better choice for brain cancer therapy. Its efficacy can be further enhanced by combination with elacridar.

Repurposing drugs in oncology (ReDO)-cimetidine as an anti-cancer agent

Cimetidine, the first H₂ receptor antagonist in widespread clinical use, has anti-cancer properties that have been elucidated in a broad range of pre-clinical and clinical studies for a number of different cancer types. These data are summarised and discussed in relation to a number of distinct mechanisms of action. Based on the evidence presented, it is proposed that cimetidine would synergise with a range of other drugs, including existing chemotherapeutics, and that further exploration of the potential of cimetidine as an anti-cancer therapeutic is warranted. Furthermore, there is compelling evidence that cimetidine administration during the peri-operative period may provide a survival benefit in some cancers. A number of possible combinations with other drugs are discussed in the supplementary material accompanying this paper.

Effective treatment of diverse medulloblastoma models with mebendazole and its impact on tumor angiogenesis

BACKGROUND

Medulloblastoma is the most common malignant brain tumor in children. Current standard treatments cure 40%-60% of patients, while the majority of survivors suffer long-term neurological sequelae. The identification of 4 molecular groups of medulloblastoma improved the clinical management with the development of targeted therapies; however, the tumor acquires resistance quickly. Mebendazole (MBZ) has a long safety record as antiparasitic in children and has been recently implicated in inhibition of various tyrosine kinases in vitro. Here, we investigated the efficacy of MBZ in various medulloblastoma subtypes and MBZ's impact on vascular endothelial growth factor receptor 2 (VEGFR2) and tumor angiogenesis.

METHODS

The inhibition of MBZ on VEGFR2 kinase was investigated in an autophosphorylation assay and a cell-free kinase assay. Mice bearing orthotopic PTCH1-mutant medulloblastoma allografts, a group 3 medulloblastoma xenograft, and a PTCH1-mutant medulloblastoma with acquired resistance to the smoothened inhibitor vismodegib were treated with MBZ. The survival benefit and the impact on tumor angiogenesis and VEGFR2 kinase function were analyzed.

RESULTS

We determined that MBZ interferes with VEGFR2 kinase by competing with ATP. MBZ selectively inhibited tumor angiogenesis but not the normal brain vasculatures in orthotopic medulloblastoma models and suppressed VEGFR2 kinase in vivo. MBZ significantly extended the survival of medulloblastoma models derived from different molecular backgrounds.

CONCLUSION

Our findings support testing of MBZ as a possible low-toxicity therapy for medulloblastomas of various molecular subtypes, including tumors with acquired vismodegib resistance. Its antitumor mechanism may be partially explained by inhibition of tumor angiogenesis.

Repurposing Drugs in Oncology (ReDO)-mebendazole as an anti-cancer agent

Mebendazole, a well-known anti-helminthic drug in wide clinical use, has anti-cancer properties that have been elucidated in a broad range of pre-clinical studies across a number of different cancer types. Significantly, there are also two case reports of anti-cancer activity in humans. The data are summarised and discussed in relation to suggested mechanisms of action. Based on the evidence presented, it is proposed that mebendazole would synergise with a range of other drugs, including existing chemotherapeutics, and that further exploration of the potential of mebendazole as an anti-cancer therapeutic is warranted. A number of possible combinations with other drugs are discussed in the Appendix.

Anti-apoptotic proteins on guard of melanoma cell survival

Apoptosis plays a pivotal role in sustaining proper tissue development and homeostasis. Evading apoptosis by cancer cells is a part of their adaption to microenvironment and therapies. Cellular integrity is predominantly maintained by pro-survival members of Bcl-2 family and IAPs. Melanoma cells are characterized by a labile and stage-dependent phenotype. Pro-survival molecules can protect melanoma cells from apoptosis and mediate other processes, thus enhancing aggressive phenotype. The essential role of Bcl-2, Mcl-1, Bcl-X(L), livin, survivin and XIAP was implicated for melanoma, often in a tumor stage-dependent fashion. In this review, the current knowledge of pro-survival machinery in melanoma is discussed.