benztropine and Breast-Neoplasms

Drug combination and drug repurposing are two strategies that allow to find novel oncological therapies, in a faster and more economical process. In our previous studies, we developed a novel model of drug combination using antineoplastic and different repurposed drugs. We demonstrated the combinations of doxorubicin (DOX) + artesunate, DOX + chloroquine, paclitaxel (PTX) + fluoxetine, PTX + fluphenazine, and PTX + benztropine induce significant cytotoxicity in Michigan Cancer Foundation-7 (MCF-7) breast cancer cells. Furthermore, it was found that 5-FU + thioridazine and 5-fluorouracil (5-FU) + sertraline can synergistically induce a reduction in the viability of human colorectal adenocarcinoma cell line (HT-29). In this study, we aim to (1) evaluate the biosafety profile of these drug combinations for non-tumoral cells and (2) determine their mechanism of action in cancer cells. To do so, human fetal lung fibroblast cells (MRC-5) fibroblast cells were incubated for 48 h with all drugs, alone and in combination in concentrations of 0.25, 0.5, 1, 2, and 4 times their half-maximal inhibitory concentration (IC

Topics: Adenosine Diphosphate; Antimalarials; Antineoplastic Agents; Artesunate; ATP Binding Cassette Transporter, Subfamily B, Member 1; Benztropine; Breast Neoplasms; Cell Line, Tumor; Chloroquine; Colonic Neoplasms; Containment of Biohazards; Doxorubicin; Drug Resistance, Neoplasm; Female; Fluorouracil; Fluoxetine; Fluphenazine; Humans; Ki-67 Antigen; MCF-7 Cells; Michigan; NF-kappa B; Paclitaxel; Poly(ADP-ribose) Polymerase Inhibitors; Ribose; Sertraline; Thioridazine

Cancer stem cells (CSCs) play major roles in cancer initiation, metastasis, recurrence and therapeutic resistance. Targeting CSCs represents a promising strategy for cancer treatment. The purpose of this study was to identify selective inhibitors of breast CSCs (BCSCs). We carried out a cell-based phenotypic screening with cell viability as a primary endpoint, using a collection of 2,546 FDA-approved drugs and drug-like molecules in spheres formed by malignant human breast gland-derived cells (HMLER-shEcad cells, representing BCSCs) and control immortalized non-tumorigenic human mammary cells (HMLE cells, representing normal stem cells). 19 compounds were identified from screening. The chemically related molecules benztropine mesylate and deptropine citrate were selected for further validation and both potently inhibited sphere formation and self-renewal of BCSCs in vitro. Benztropine mesylate treatment decreased cell subpopulations with high ALDH activity and with a CD44+/CD24- phenotype. In vivo, benztropine mesylate inhibited tumor-initiating potential in a 4T1 mouse model. Functional studies indicated that benztropine mesylate inhibits functions of CSCs via the acetylcholine receptors, dopamine transporters/receptors, and/or histamine receptors. In summary, our findings identify benztropine mesylate as an inhibitor of BCSCs in vitro and in vivo. This study also provides a screening platform for identification of additional anti-CSC agents.

Topics: Animals; Antineoplastic Agents; Antiparkinson Agents; Benztropine; Biomarkers; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Cell Self Renewal; Cell Survival; Disease Models, Animal; Drug Repositioning; Drug Screening Assays, Antitumor; Female; Humans; Immunophenotyping; Mice; Neoplastic Stem Cells; Small Molecule Libraries; Spheroids, Cellular; Tumor Cells, Cultured; Xenograft Model Antitumor Assays