Repurposing fluphenazine to suppress melanoma brain, lung and bone metastasis by inducing G0/G1 cell cycle arrest and apoptosis and disrupting autophagic flux.

Brain metastasis is the main cause of treatment failure and melanoma-related death. Inadequate concentrations of therapeutic drugs in the brain due to the blood-brain barrier (BBB) pose a major challenge in the treatment of brain metastasis. Antipsychotics can cross the BBB to reach the brain. Fluphenazine (FPZ) inhibits the survival of melanoma cells in vitro. However, its efficacy in suppressing the metastasis of melanoma, especially brain metastasis, remains unknown. Therefore, we explored whether fluphenazine (FPZ) can be repurposed for treating melanoma metastasis. A subcutaneous tumor model, and experimental metastasis models that simulate the outgrowth of melanoma cells in the brain, lung, and bone were established to verify the inhibitory effect of FPZ on melanoma cells. FPZ showed potential inhibitory effects against melanoma both in vivo and in vitro. It induced G0/G1 phase arrest and-mitochondrion-mediated intrinsic apoptosis, and inhibited autophagic flux in melanoma cells in vitro. In vivo, subcutaneous tumor, brain, lung, and bone models of metastatic melanoma were established. Intraperitoneal injection of FPZ (8 mg/kg) significantly inhibited melanoma growth in the subcutaneous and experimental metastasis models. In a lung metastasis model, FPZ reduced the proportion of M2 macrophages and increased the proportion of CD8+ T cells and NK cells in vivo, thereby promoting an anticancer immune response. The findings of this study indicate that FPZ is a potential drug candidate for treating metastatic melanoma.

OSW-1 induces apoptosis and cyto-protective autophagy, and synergizes with chemotherapy on triple negative breast cancer metastasis.

PURPOSE: Triple-negative breast cancer (TNBC) is the most malignant subtype of breast cancer. As yet, chemotherapy with drugs such as doxorubicin is the main treatment strategy. However, drug resistance and dose-dependent toxicities restrict their clinical use. Natural products are major sources of anti-tumor drugs. OSW-1 is a natural compound with strong anti-cancer effects in several types of cancer, but its effects on the efficacy of chemotherapy in TNBC and its underlying mechanism remain unclear. METHODS: The inhibitory activities of OSW-1 and its combination with several chemotherapy drugs were tested using in vitro assays and in vivo subcutaneous and metastatic mouse TNBC models. The effects of the mono- and combination treatments on TNBC cell viability, apoptosis, autophagy and related signaling pathways were assessed using MTT, flow cytometry, RNA sequencing and immunology-based assays. In addition, the in vivo inhibitory effects of OSW-1 and (combined) chemotherapies were evaluated in subcutaneous and metastatic mouse tumor models. RESULTS: We found that OSW-1 induces Ca2+-dependent mitochondria-dependent intrinsic apoptosis and cyto-protective autophagy through the PI3K-Akt-mTOR pathway in TNBC cells in vitro. We also found that OSW-1 and doxorubicin exhibited strong synergistic anti-TNBC capabilities both in vivo and in vitro. Combination treatment strongly inhibited spontaneous and experimental lung metastases in 4T1 mouse models. In addition, the combination strategy of OSW-1 + Carboplatin + Docetaxel showed an excellent anti-metastatic effect in vivo. CONCLUSIONS: Our data revealed the mode of action and molecular mechanism underlying the effect of OSW-1 against TNBC, and provided a useful guidance for improving the sensitivity of TNBC cells to conventional chemotherapeutic drugs, which warrants further investigation.

Repurposed antipsychotic chlorpromazine inhibits colorectal cancer and pulmonary metastasis by inducing G2/M cell cycle arrest, apoptosis, and autophagy.

PURPOSE: Despite efforts in developing effective therapeutic strategies, colorectal cancer (CRC) remains one of the most prevalent and lethal neoplasms. Repurposing approved drugs is an alluring strategy for developing anticancer agents. Some antipsychotic drugs, including chlorpromazine (CPZ), possess anticancer activities. However, the pharmacological effects of CPZ on CRC have not been clearly established. METHODS: MTT assay, flow cytometry, western blotting analysis, subcutaneous mice tumor, and tail-vein-injection established lung metastasis model were used to investigate the anticancer effects of CPZ on CRC and the underlying mechanism. RESULTS: We found that CPZ effectively suppressed CRC by inducing G2/M cell cycle arrest and apoptosis. Cell cycle arrest was associated with decreased activities of the cdc2/cyclin B1 complex, including suppressed expression of cyclin B1, cdc2 and cdc25c, and elevated expression levels of phosphorylated cdc2 (Tyr15). Moreover, CPZ suppressed mitochondrial membrane potential and elevated reactive oxygen species levels in cancer cells, implying that it induces mitochondria-dependent intrinsic apoptosis. CPZ blocked the autophagic flux and induced cytotoxic autophagy in CRC cells. In addition, CPZ suppressed tumor growth in two subcutaneous mouse models without causing obvious side effects. Analysis of the abundance of immune cells in the tumor microenvironment revealed that CPZ did not have an effect on their proportions. Furthermore, it significantly suppressed the lung metastasis of CT26 cells and prolonged mice survival. CONCLUSION: These findings indicated that repurposing CPZ is a novel treatment strategy for CRC patients.

Design, synthesis, and biological evaluation of benzo[b]thiophene 1,1-dioxide derivatives as potent STAT3 inhibitors.

As a member of the signal transducer and activator of transcription (STAT) family, STAT3 plays a critical role in several biological pathways such as cell proliferation, migration, survival, and differentiation. Due to abnormal continuous activation in tumors, inhibition of STAT3 has emerged as an attractive approach for the treatment of various cancer cells. Herein, we report a series of novel STAT3 inhibitors based on benzo[b]thiophene 1,1-dioxide scaffold and evaluated their anticancer potency. Among them, compound 8b exhibited the best activity against cancer cells. Compound 8b induced apoptosis and blocked the cell cycle. Meanwhile, 8b reduced intracellular ROS content and caused the loss of mitochondrial membrane potential. Further research revealed that 8b significantly blocked STAT3 phosphorylation and STAT3-dependent dual-luciferase reporter gene experiments showed that compound 8b has a marked inhibition of STAT3-mediated Firefly luciferase activity. Molecular modeling studies revealed compound 8b occupied the pocket well with the SH2 domain in a favorable conformation.

Repurposing of antipsychotic trifluoperazine for treating brain metastasis, lung metastasis and bone metastasis of melanoma by disrupting autophagy flux.

Targeted therapies and immunotherapy have brought substantial benefits to patients with melanoma. However, brain metastases remain the biggest threat to the survival and quality of life of melanoma patients. One of the major challenges to an effective therapy is the inability of drugs to penetrate the blood-brain barrier (BBB). Anti-schizophrenic drugs can cross the BBB, and many of them have demonstrated anti-cancer effects. Repurposing existing drugs for new clinical indications is an alluring strategy for anticancer drug discovery. Herein, we applied this strategy and screened a small collection of existing anti-schizophrenic drugs to use as anti-melanoma agents. Among them, trifluoperazine dihydrochloride (TFP) exhibited promising potencies for suppressing the growth and metastasis of melanoma, both in vitro and in vivo. TFP obviously suppressed the viability of melanoma cells within the micromolar range and inhibited the growth of melanoma in the subcutaneous mice models. Notably, intraperitoneal (i.p.) administration of TFP (40 mg/kg/day) obviously inhibited the growth of intra-carotid-injection established melanoma brain metastasis and extended the survival of brain metastasis-bearing mice. Moreover, TFP significantly suppressed lung metastasis and bone metastasis of melanoma in preclinical metastasis models. Mechanistically, TFP caused G0/G1 cell cycle arrest and mitochondrial-dependent intrinsic apoptosis of melanoma cells. In addition, TFP treatment increased the expression of microtubule associated protein 1 light chain 3 beta-II (LC3B-II) and p62 in vitro, suggesting an inhibition of autophagic flux. TFP decreased LysoTracker Red uptake after treatment, indicating impaired acidification of lysosomes. Moreover, the colocalization of LC3 with lysosomal-associated membrane protein 1 (LAMP1), a lysosome marker, was also suppressed after TFP treatment, suggesting that TFP might block the fusion of autophagosomes with lysosomes, which led to autophagosome accumulation. Taken together, our data highlight the potential of repurposing TFP as a new adjuvant drug for treating melanoma patients with brain, lung, and bone metastases.