Combinatorial treatments that overcome PDGFRβ-driven resistance of melanoma cells to V600EB-RAF inhibition.
Combinatorial treatments that overcome PDGFRβ-driven resistance of melanoma cells to V600EB-RAF inhibition.
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DOI：
10.1158/0008-5472.can-11-0140
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发表时间：
2011-08-01
期刊：
影响因子：
11.2
通讯作者：
Lo RS
中科院分区：
文献类型：
--
作者：
Shi H;Kong X;Ribas A;Lo RS
在50-60%的黑色素瘤中发现V600 EB-RAF突变，抑制V600 EB-RAF激酶的新型药物PLX 4032/vemurafenib和GSK 2118436实现了显著的临床响应率。然而，正如预期的那样，大多数黑色素瘤患者对这些药物产生了获得性临床耐药性。在体内肿瘤匹配短期培养物中或体外黑色素瘤细胞系中出现的PLX 4032/维罗非尼耐药性不是由获得V600 EB-RAF继发突变引起的，而是由PDGFRβ或N-RAS上调引起的，这分别导致对MEK抑制剂的耐药性或敏感性。在这项研究中，我们定义了一种靶向组合策略，以克服黑素瘤细胞系或短期培养物中的PLX 4032/维罗非尼耐药性，其中耐药性是由PDGFRβ上调（PPRM细胞系）驱动的，从而实现协同生长抑制和细胞毒性。PPRM细胞系显示p-ERK和p-AKT双重上调，并且它们对特定小分子抑制剂的生长抑制反应与p-ERK、p-AKT、p-p70 S6 K水平相关。V600 EB-RAF抑制和RTK-PI 3 K-AKT-mTORC轴的协调抑制导致功能上显著的反弹信号传导，说明了稳健和动态的网络连接。联合B-RAF、PI 3 K和mTORC 1/2抑制抑制即刻早期和延迟代偿信号传导，导致高度协同的生长抑制反应，但细胞毒性反应效率较低。相比之下，MEK 1/2、PI 3 K和mTORC 1/2抑制剂的组合始终以高效的方式触发细胞凋亡。总之，我们的研究结果提供了一个合理的策略，以指导在V600 EB-RAF抑制剂治疗期间复发的预先确定的患者子集的临床测试。
V600EB-RAF mutation is found in 50–60% of melanomas, and the novel agents PLX4032/vemurafenib and GSK2118436 that inhibit the V600EB-RAF kinase achieve a remarkable clinical response rate. However, as might be expected, acquired clinical resistance to these agents arises in most melanoma patients. PLX4032/vemurafenib resistance that arises in vivo in tumor-matched short-term cultures or in vitro in melanoma cell lines is not caused by acquisition of secondary mutations in V600EB-RAF but rather by upregulating PDGFRβ or N-RAS which results in resistance or sensitivity to MEK inhibitors, respectively. In this study, we define a targeted combinatorial strategy to overcome PLX4032/vemurafenib resistance in melanoma cell lines or short-term culture where the resistance is driven by PDGFRβ upregulated (PPRM cell lines), achieving synergistic growth inhibition and cytotoxicity. PPRM cell lines show dual p-ERK and p-AKT upregulation, and their growth inhibitory responses to specific small molecule inhibitors correlated with p-ERK, p-AKT, p-p70S6K levels. Coordinate inhibition of V600EB-RAF inhibition and the RTK-PI3K-AKT-mTORC axis led to functionally significant rebound signaling, illustrating a robust and dynamic network connectivity. Combined B-RAF, PI3K and mTORC1/2 inhibition suppressed both immediate-early and delayed compensatory signaling, resulting in a highly synergistic growth inhibitory response but less efficient cytotoxic response. In contrast, the combination of MEK1/2, PI3K and mTORC1/2 inhibitors consistently triggered apoptosis in a highly efficient manner. Together, our findings offer a rational strategy to guide clinical testing in pre-identified subsets of patients who relapse during treatment with V600EB-RAF inhibitors.