circNEIL3 inhibits tumor metastasis through recruiting the E3 ubiquitin ligase Nedd4L to degrade YBX1.

Distant metastasis is a major contributor to cancer-related mortality. However, the role of circRNAs in this process remains unclear. Herein, we profiled the circRNA expression in a cohort of 68 colorectal carcinoma (CRC) primary tumors and their paired liver metastatic lesions. By overlapping with the TGFß-responsive circRNAs, circNEIL3 (hsa_circ_0001460) was identified as a TGFß-repressive and metastasis-related circRNA. Functionally, circNEIL3 effectively inhibited tumor metastasis in both and in vivo and in vivo models of various cancer types. Mechanistically, circNEIL3 exerts its metastasis-repressive function through its direct interaction with oncogenic protein, Y-box-binding protein 1 (YBX1), which consequently promotes the Nedd4L-mediated proteasomal degradation of YBX1. Importantly, circNEIL3 expression was negatively correlated to YBX1 protein level and metastatic tendency in CRC patient samples. Collectively, our findings indicate the YBX1-dependent antimetastatic function of circNEIL3 and highlight the potential of circNEIL3 as a biomarker and therapeutic option in cancer treatment.

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.

Structural basis for efonidipine block of a voltage-gated Ca2+ channel.

Efonidipine is a dual L-/T- type calcium channel blocker with a slow onset of action and a long lasting effect that exibihits antihypertensive and nephroprotective effects. differs from most other DHPs which can induce reflex tachycardia. Efonidipine reduces blood pressure without decreasing cardiac output and exerts organ-protective effects on the heart and kidney. In order to investigate how efonidipine block voltage-gated Ca2+ channel, we determined the crystal structure of CaVAb in complex with efonidipine at atomic resolution using x-ray crystallography. Our results reveal that efonidipine targets the central cavity of a model voltage-gated calcium channel underneath its selectivity filter and occlude the channel in an inactivated state. Binding of efonidipine does not break down the fourfold symmetry of the quaternary structure and its pore structure. Our work provides the structural basis for efonidipine block of a voltage-gated Ca2+ channel at the molecular level.

Targeting Ferroptosis Pathway to Combat Therapy Resistance and Metastasis of Cancer.

Ferroptosis is an iron-dependent regulated form of cell death caused by excessive lipid peroxidation. This form of cell death differed from known forms of cell death in morphological and biochemical features such as apoptosis, necrosis, and autophagy. Cancer cells require higher levels of iron to survive, which makes them highly susceptible to ferroptosis. Therefore, it was found to be closely related to the progression, treatment response, and metastasis of various cancer types. Numerous studies have found that the ferroptosis pathway is closely related to drug resistance and metastasis of cancer. Some cancer cells reduce their susceptibility to ferroptosis by downregulating the ferroptosis pathway, resulting in resistance to anticancer therapy. Induction of ferroptosis restores the sensitivity of drug-resistant cancer cells to standard treatments. Cancer cells that are resistant to conventional therapies or have a high propensity to metastasize might be particularly susceptible to ferroptosis. Some biological processes and cellular components, such as epithelial-mesenchymal transition (EMT) and noncoding RNAs, can influence cancer metastasis by regulating ferroptosis. Therefore, targeting ferroptosis may help suppress cancer metastasis. Those progresses revealed the importance of ferroptosis in cancer, In order to provide the detailed molecular mechanisms of ferroptosis in regulating therapy resistance and metastasis and strategies to overcome these barriers are not fully understood, we described the key molecular mechanisms of ferroptosis and its interaction with signaling pathways related to therapy resistance and metastasis. Furthermore, we summarized strategies for reversing resistance to targeted therapy, chemotherapy, radiotherapy, and immunotherapy and inhibiting cancer metastasis by modulating ferroptosis. Understanding the comprehensive regulatory mechanisms and signaling pathways of ferroptosis in cancer can provide new insights to enhance the efficacy of anticancer drugs, overcome drug resistance, and inhibit cancer metastasis.

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.

Antipsychotic Drug Trifluoperazine Suppresses Colorectal Cancer by Inducing G0/G1 Arrest and Apoptosis.

Repurposing existing drugs for cancer treatment is an effective strategy. An approved antipsychotic drug, trifluoperazine (TFP), has been reported to have potential anticancer effects against several cancer types. Here, we investigated the effect and molecular mechanism of TFP in colorectal cancer (CRC). In vitro studies showed that TFP induced G0/G1 cell cycle arrest to dramatically inhibit CRC cell proliferation through downregulating cyclin-dependent kinase (CDK) 2, CDK4, cyclin D1, and cyclin E and upregulating p27. TFP also induced apoptosis, decreased mitochondrial membrane potential, and increased reactive oxygen species levels in CRC cells, indicating that TFP induced mitochondria-mediated intrinsic apoptosis. Importantly, TFP significantly suppressed tumor growth in two CRC subcutaneous tumor models without side effects. Interestingly, TFP treatment increased the expression levels of programmed death-1 ligand 1 (PD-L1) in CRC cells and programmed death-1 (PD-1) in tumor-infiltrating CD4+ and CD8+ T cells, implying that the combination of TFP with an immune checkpoint inhibitor, such as an anti-PD-L1 or anti-PD-1 antibody, might have synergistic anticancer effects. Taken together, our study signifies that TFP is a novel treatment strategy for CRC and indicates the potential for using the combination treatment of TFP and immune checkpoint blockade to increase antitumor efficiency.

Repositioning antipsychotic fluphenazine hydrochloride for treating triple negative breast cancer with brain metastases and lung metastases.

Triple negative breast cancer (TNBC) patients have a high risk of brain metastases. This deadly disease represents a major challenge for successful treatment, in part because of the poor ability of drugs to penetrate the blood-brain barrier. Antipsychotic drugs show good bioavailability in the brain, and some of them have exhibited anticancer effects in several cancer types. In this study, we investigated the potential of repurposing fluphenazine hydrochloride (Flu) for the treatment of TNBC and the brain metastases. Our data showed that Flu inhibited survival of metastatic TNBC cells. It induced G0/G1 cell cycle arrest and promoted mitochondria-mediated intrinsic apoptosis in vitro. Pharmacokinetic studies in BALB/c mice showed a brain/plasma drug concentration ratio of Flu above 25 for at least 24 hours after dosing. Flu moderately suppressed tumor growth in a TNBC subcutaneous xenograft mouse model. Importantly, Flu exhibited good anti-metastatic potential in a mouse brain metastasis model with an inhibition rate of 85%. In addition, Flu showed a strong inhibitory effect on spontaneous lung metastasis. Moreover, Flu didn't cause serious side effects in the mice. Taken together, this study prompts further preclinical and clinical investigation into repurposing Flu for treating metastatic TNBC patients, which urgently need new treatment options.

The antipsychotic agent trifluoperazine hydrochloride suppresses triple-negative breast cancer tumor growth and brain metastasis by inducing G0/G1 arrest and apoptosis.

Women with aggressive triple-negative breast cancer (TNBC) are at high risk of brain metastasis, which has no effective therapeutic option partially due to the poor penetration of drugs across the blood-brain barrier. Trifluoperazine (TFP) is an approved antipsychotic drug with good bioavailability in brain and had shown anticancer effect in several types of cancer. It drives us to investigate its activities to suppress TNBC, especially the brain metastasis. In this study, we chose three TNBC cell lines MDA-MB-468, MDA-MB-231, and 4T1 to assess its anticancer activities along with the possible mechanisms. In vitro, it induced G0/G1 cell cycle arrest via decreasing the expression of both cyclinD1/CDK4 and cyclinE/CDK2, and stimulated mitochondria-mediated apoptosis. In vivo, TFP suppressed the growth of subcutaneous xenograft tumor and brain metastasis without causing detectable side effects. Importantly, it prolonged the survival of mice bearing brain metastasis. Immunohistochemical analysis of Ki67 and cleaved caspase-3 indicated TFP could suppress the growth and induce apoptosis of cancer cells in vivo. Taken together, TFP might be a potential available drug for treating TNBC with brain metastasis, which urgently needs novel treatment options.