Concomitant inhibition of AKT and autophagy is required for efficient cisplatin-induced apoptosis of metastatic skin carcinoma
Concomitant inhibition of AKT and autophagy is required for efficient cisplatin-induced apoptosis of metastatic skin carcinoma
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DOI：
10.1002/ijc.25300
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发表时间：
2010-12-15
影响因子：
6.4
通讯作者：
Garmyn, Marjan
中科院分区：
文献类型：
--
作者：
Claerhout, Sofie;Verschooten, Lien;Garmyn, Marjan
皮肤鳞状细胞癌(CSCC)是高加索人最常见的癌症之一。尽管早期皮肤癌的治愈率很高，预后也很好，但晚期CSCC对包括顺铂在内的化疗表现出抗药性。已知PI3-K/AKT通路在皮肤癌的发生和对治疗药物的耐药性中都有作用。在这项研究中，我们使用了代表不同恶性转化阶段的角质形成细胞的等基因细胞系，这些角质形成细胞来自一名免疫抑制患者的额部发育不良皮肤(PM1)、原发皮肤鳞状细胞癌(MET1)及其淋巴转移(MET4)。我们发现，皮肤肿瘤的进展与增强AKT激活和增强对顺铂诱导的细胞凋亡的抵抗力是平行的。药理学的AKT抑制或特异性的AKT1敲除，使抗凋亡的MET1细胞和较小程度的MET4细胞对顺铂介导的细胞死亡敏感。通过串联MRFP-GFP荧光显微镜和电子显微镜分析完整的自噬成熟过程，观察到MET4自噬诱导，自噬蛋白标记物LC3-II的积累证明了这一点。用3-甲基腺嘌呤或特异性ATG5拮抗自噬过程，可阻断顺铂与AKT抑制剂联合作用增强的细胞毒性，从而揭示自噬在化疗耐药中的关键作用。综上所述，这些结果表明，为了提高AKT抑制与标准化疗药物顺铂联合治疗晚期皮肤癌的疗效，需要同时抑制自噬。
Cutaneous squamous cell carcinoma (cSCC) is one of the most common cancers in the Caucasian population. Although early stages of skin cancer have a high curability and excellent prognosis, advanced cSCC shows resistance to chemotherapy, including cisplatin. The PI3-K/AKT pathway is known to have a role in both skin cancer development and resistance to therapeutic drugs. In this study, we used isogenic cell lines representing different stages of malignant transformation of the keratinocytes that were derived from dysplastic forehead skin (PM1), primary cutaneous SCC (MET1) and its lymph node metastasis (MET4) of an immunosuppressed patient. We show that skin tumor progression parallels enhanced AKT activation and increased resistance to cisplatin-induced apoptosis. Pharmacological AKT inhibition, or specific AKT1 knock down, sensitizes the apoptosis-resistant MET1 and, to a lesser extent, MET4 cells to cisplatin-mediated cell death. Concomitantly autophagy induction was observed in MET4, as demonstrated by accumulation of the autophagic protein marker LC3-II, by analysis of full autophagosome maturation process using tandem mRFP-GFP fluorescence microscopy and by electron microscopy. Counteracting the autophagic process by 3-methyladenine or specific ATG5 knock down enhanced cytotoxicity of cisplatin combined with AKT inhibitor, thus revealing a key role for autophagy in chemoresistance. Taken together, these results indicate that concomitant inhibition of autophagy is required to increase the therapeutic benefit of AKT inhibition for combination therapy with the standard chemotherapeutic agent cisplatin in advanced skin carcinoma.