Melanoma is a malignant neoplasia that is highly resistant to chemotherapy and radiotherapy and is associated with poor prognosis in advanced stage. Targeting melanoma that harbors the common BRAFV600E mutation with kinase inhibitors, such as vemurafenib, reduces tumor burden, but these tumors frequently acquire resistance to these drugs. We previously proposed that T-type calcium channel (TTCC) expression may serve as a biomarker for melanoma progression and prognosis, and we showed that TTCC blockers reduce migration and invasion rates because of autophagy blockade only in BRAFV600E-mutant melanoma cells. Here, we demonstrated that high expression of the TTCC Cav3.1 isoform is related to autophagic status in vemurafenib-resistant BRAFV600E-mutant melanoma cells and human biopsies, and in silico analysis revealed an enrichment of Cav3.1 expression in post-treatment melanomas. We also demonstrated that the TTCC blocker mibefradil induces apoptosis and impairs migration and invasion via inhibition of autophagy in resistant melanoma cells and mouse xenograft models. Moreover, we identified an association between PTEN status and Cav3.1 expression in these cells as a marker of sensitivity to combination therapy in resistant cells. Together, our results suggest that TTCC blockers offer a potential targeted therapy in resistant BRAFV600E-mutant melanoma and a therapeutic strategy to reduce progression toward BRAF inhibitor resistance.

中文翻译：

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T型钙通道作为抗维拉非尼BRAFV600E黑色素瘤的潜在治疗靶标。

黑色素瘤是一种恶性肿瘤，对化学疗法和放射疗法高度耐药，并与晚期预后不良相关。具有维拉非尼等激酶抑制剂的具有常见BRAFV600E突变的靶向黑色素瘤可减轻肿瘤负担，但这些肿瘤经常获得对这些药物的耐药性。我们以前提出T型钙通道（TTCC）的表达可以作为黑色素瘤进展和预后的生物标志物，并且我们表明TTCC阻断剂仅在BRAFV600E突变型黑色素瘤细胞中由于自噬被阻断而降低了迁移和侵袭率。在这里，我们证明了TTCC Cav3.1亚型的高表达与维拉非尼耐药的BRAFV600E突变型黑色素瘤细胞和人体活检组织中的自噬状态有关，并且计算机分析表明Cav3的富集。在治疗后的黑色素瘤中有1种表达。我们还证明了TTCC阻断剂米贝地尔在抗性黑素瘤细胞和小鼠异种移植模型中通过抑制自噬来诱导凋亡并损害迁移和侵袭。此外，我们确定了这些细胞中PTEN状态与Cav3.1表达之间的关联，作为对耐药细胞中联合疗法敏感性的标志。总之，我们的结果表明，TTCC阻滞剂可在耐药的BRAFV600E突变型黑色素瘤中提供潜在的靶向治疗，并提供降低BRAF抑制剂耐药性进展的治疗策略。我们确定了这些细胞中PTEN状态与Cav3.1表达之间的关联，作为对耐药细胞中联合疗法敏感性的标志。总之，我们的结果表明，TTCC阻滞剂可在耐药的BRAFV600E突变型黑色素瘤中提供潜在的靶向治疗，并提供降低BRAF抑制剂耐药性进展的治疗策略。我们确定了这些细胞中PTEN状态与Cav3.1表达之间的关联，作为对耐药细胞中联合疗法敏感性的标志。总之，我们的结果表明，TTCC阻滞剂可在耐药的BRAFV600E突变型黑色素瘤中提供潜在的靶向治疗，并提供降低BRAF抑制剂耐药性进展的治疗策略。