Murali Vasanth Siruvallur, Rajendran Divya, Isogai Tadamoto, DeBerardinis Ralph J, Danuser Gaudenz
Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA.
Cecil H. and Ida Green Center for Systems Biology, UT Southwestern Medical Center, Dallas, TX, USA.
bioRxiv. 2024 Jan 11:2024.01.09.574940. doi: 10.1101/2024.01.09.574940.
Cutaneous melanomas harboring a B-Raf mutation are treated with immune check point inhibitors or kinase inhibitor combination therapies relying on MAPK inhibitors (MAPKi) Dabrafenib and Trametinib (Curti and Faries, 2021). However, cells become resistant to treatments over the timespan of a few months. Resistance to MAPKi has been associated with adoption of an aggressive amoeboid phenotype characterized by elevated RhoA signaling, enhanced contractility and thick cortical filamentous actin (F-actin) structures (Kim et al., 2016; Misek et al., 2020). Targeting active RhoA through Rho-kinase (ROCK) inhibitors, either alone or in combination with immunotherapies, reverts MAPKi-resistance (Misek et al., 2020; Orgaz et al., 2020). Yet, the mechanisms for this behavior remain largely unknown. Given our recent findings of cytoskeleton's role in cancer cell proliferation (Mohan et al., 2019), survival (Weems et al., 2023), and metabolism (Park et al., 2020), we explored possibilities by which RhoA-driven changes in cytoskeleton structure may confer resistance. We confirmed elevated activation of RhoA in a panel of MAPKi-resistant melanoma cell lines, leading to a marked increase in the presence of contractile F-actin bundles. Moreover, these cells had increased glucose uptake and glycolysis, a phenotype disrupted by pharmacological perturbation of ROCK. However, glycolysis was unaffected by disruption of F-actin bundles, indicating that glycolytic stimulation in MAPKi-resistant melanoma is independent of F-actin organization. Instead, our findings highlight a mechanism in which elevated RhoA signaling activates ROCK, leading to the activation of insulin receptor substrate 1 (IRS1) and P85 of the PI3K pathway, which promotes cell surface expression of GLUT1 and elevated glucose uptake. Application of ROCK inhibitor GSK269962A results in reduced glucose uptake and glycolysis, thus impeding cell proliferation. Our study adds a mechanism to the proposed use of ROCK inhibitors for long-term treatments on MAPKi-resistant melanomas.
携带B-Raf突变的皮肤黑色素瘤采用免疫检查点抑制剂或依赖丝裂原活化蛋白激酶抑制剂（MAPKi）达拉非尼和曲美替尼的激酶抑制剂联合疗法进行治疗（柯蒂和法里斯，2021年）。然而，在几个月的时间里，细胞会对治疗产生耐药性。对MAPKi的耐药性与采用侵袭性阿米巴样表型有关，其特征是RhoA信号升高、收缩性增强和皮质丝状肌动蛋白（F-肌动蛋白）结构增厚（金等人，2016年；米塞克等人，2020年）。通过Rho激酶（ROCK）抑制剂单独或与免疫疗法联合靶向活性RhoA，可逆转对MAPKi的耐药性（米塞克等人，2020年；奥尔加兹等人，2020年）。然而，这种行为的机制在很大程度上仍然未知。鉴于我们最近发现细胞骨架在癌细胞增殖（莫汉等人，2019年）、存活（威姆斯等人，2023年）和代谢（帕克等人，2020年）中的作用，我们探索了RhoA驱动的细胞骨架结构变化可能导致耐药性的可能性。我们证实在一组对MAPKi耐药的黑色素瘤细胞系中RhoA的活化升高，导致收缩性F-肌动蛋白束的存在显著增加。此外，这些细胞的葡萄糖摄取和糖酵解增加，这一表型因ROCK的药理学扰动而被破坏。然而，糖酵解不受F-肌动蛋白束破坏的影响，表明对MAPKi耐药的黑色素瘤中的糖酵解刺激独立于F-肌动蛋白组织。相反，我们的研究突出了一种机制，即升高的RhoA信号激活ROCK，导致胰岛素受体底物1（IRS1）和PI3K途径的P85活化，从而促进GLUT1的细胞表面表达和葡萄糖摄取增加。应用ROCK抑制剂GSK269962A可导致葡萄糖摄取和糖酵解减少，从而阻碍细胞增殖。我们的研究为提议使用ROCK抑制剂对MAPKi耐药的黑色素瘤进行长期治疗增加了一种机制。
