This study employed the drug affinity responsive target stability (DARTS) technique to investigate the molecular mechanism of the antipsychotic drug penfluridol against melanoma, revealing the biological pathway to exert its effect on the HSPA6/p53/p21 signaling axis. Experiments such as the methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay and cell colony formation ability assay confirmed that penfluridol could significantly downregulate the expression of cyclin D1 and cyclin-dependent kinase 4 (CDK4) in melanoma A375 and B16 cells, induce cell cycle arrest in the G1 phase, and thus inhibit the proliferation of melanoma cells. Meanwhile, the results of Western blot, Hoechst 33342 staining and Annexin V-FITC/PI double staining experiments showed that penfluridol could significantly downregulate the expression of Bcl-2 and upregulate the expression of Bax and cleaved caspase-3, inducing cell apoptosis. Further, the DARTS technique was used to identify heat shock 70 kD protein 6 (HSPA6) as the key target bound by penfluridol. Penfluridol activates the p53/p21 pathway by upregulating HSPA6. Knocking down HSPA6 reverses not only the activation of the p53/p21 pathway mediated by penfluridol but also the associated cell cycle arrest and apoptosis. Animal experiments on tumor-bearing mice also confirmed that knocking down HSPA6 could reverse the in vivo anti-tumor activity of penfluridol. This study clarified that penfluridol can inhibit the progression of melanoma by targeting HSPA6 to activate the p53/p21 signaling axis, providing a new perspective for the repositioning of antipsychotic drugs in cancer treatment.

OBJECTIVE To investigate the effects of L-mimosine on the proliferation and apoptosis of melanoma cells and its molecular mechanisms.METHODS The effects of different concentrations of L-mimosine on the viability of melanoma A375 and B16 cells were examined by the MTT assay.The ability of L-Mimosine to affect colony formation was assessed by the plate colony for-mation assay.The effects of L-mimosine on cell apoptosis,reactive oxygen species(ROS),and mitochondrial membrane potential were analyzed by flow cytometry.The changes in the expression levels of intracellular proteins such as Bcl-2,Bax,Cyt C,Cleaved Caspase-3,Cleaved Caspase-9,Bim-EL,Bad,p-JNK,p-c-Jun,p-MKK4,and p-ASK1 were detected by Western blot.The tumor-bearing mouse model was subjected to histological and TUNEL staining analysis of tumor tissues after treatment with normal saline,L-mimosine alone,and L-mimosine in combination with N-acetylcysteine(NAC).RESULTS L-mimosine significantly inhibited the prolifera-tion of A375 and B16 cells and significantly promoted cell apoptosis.Western blot analysis showed that L-mimosine could significantly increase the content of Apaf-1 and Cyt C in the cytoplasm,up-regulate the expression of Cleaved PARP,Cleaved Caspase-3,Cleaved Caspase-9,Bax,Bim-EL and Bad,and down-regulate the expression of anti-apoptotic protein Bcl-2.Further experiments showed that L-mimosine significantly induced the accumulation of ROS in A375 cells and activated the JNK/c-Jun signaling pathway,which was manifested by the significant increase of p-JNK,p-c-Jun,p-MKK4 and p-ASK1.Additionally,the antioxidant NAC could significantly antagonize the ROS accumulation induced by L-mimosine,thereby reversing the pro-apoptotic effects of L-mi-mosine on melanoma cells.In vivo experiments,NAC also significantly antagonized the tumor growth inhibition induced by L-mi-mosine,as evidenced by increased tumor volume and reversed expression levels of apoptosis-related proteins.CONCLUSION L-mi-mosine induces apoptosis in melanoma cells by increasing ROS levels and activating the JNK/c-Jun signaling pathway.

OBJECTIVE To investigate the effects of L-mimosine on the proliferation and apoptosis of melanoma cells and its molecular mechanisms.METHODS The effects of different concentrations of L-mimosine on the viability of melanoma A375 and B16 cells were examined by the MTT assay.The ability of L-Mimosine to affect colony formation was assessed by the plate colony for-mation assay.The effects of L-mimosine on cell apoptosis,reactive oxygen species(ROS),and mitochondrial membrane potential were analyzed by flow cytometry.The changes in the expression levels of intracellular proteins such as Bcl-2,Bax,Cyt C,Cleaved Caspase-3,Cleaved Caspase-9,Bim-EL,Bad,p-JNK,p-c-Jun,p-MKK4,and p-ASK1 were detected by Western blot.The tumor-bearing mouse model was subjected to histological and TUNEL staining analysis of tumor tissues after treatment with normal saline,L-mimosine alone,and L-mimosine in combination with N-acetylcysteine(NAC).RESULTS L-mimosine significantly inhibited the prolifera-tion of A375 and B16 cells and significantly promoted cell apoptosis.Western blot analysis showed that L-mimosine could significantly increase the content of Apaf-1 and Cyt C in the cytoplasm,up-regulate the expression of Cleaved PARP,Cleaved Caspase-3,Cleaved Caspase-9,Bax,Bim-EL and Bad,and down-regulate the expression of anti-apoptotic protein Bcl-2.Further experiments showed that L-mimosine significantly induced the accumulation of ROS in A375 cells and activated the JNK/c-Jun signaling pathway,which was manifested by the significant increase of p-JNK,p-c-Jun,p-MKK4 and p-ASK1.Additionally,the antioxidant NAC could significantly antagonize the ROS accumulation induced by L-mimosine,thereby reversing the pro-apoptotic effects of L-mi-mosine on melanoma cells.In vivo experiments,NAC also significantly antagonized the tumor growth inhibition induced by L-mi-mosine,as evidenced by increased tumor volume and reversed expression levels of apoptosis-related proteins.CONCLUSION L-mi-mosine induces apoptosis in melanoma cells by increasing ROS levels and activating the JNK/c-Jun signaling pathway.