Wahoski Claudia C, Singh Bhuminder
Program in Cancer Biology, Vanderbilt University, Nashville, TN 37232, USA.
Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
Cancers (Basel). 2024 Jul 6;16(13):2472. doi: 10.3390/cancers16132472.
Colorectal cancer (CRC) is one of the most diagnosed cancers and a leading contributor to cancer-related deaths in the United States. Clinically, standard treatment regimens include surgery, radiation, and chemotherapy; however, there has been increasing development and clinical use of targeted therapies for CRC. Unfortunately, many patients develop resistance to these treatments. Cetuximab, the first targeted therapy approved to treat advanced CRC, is a monoclonal antibody that targets the epidermal growth factor receptor and inhibits downstream pathway activation to restrict tumor cell growth and proliferation. CRC resistance to cetuximab has been well studied, and common resistance mechanisms include constitutive signal transduction through downstream protein mutations and promotion of the epithelial-to-mesenchymal transition. While the most common resistance mechanisms are known, a proportion of patients develop resistance through unknown mechanisms. One protein predicted to contribute to therapy resistance is RAC1, a small GTPase that is involved in cytoskeleton rearrangement, cell migration, motility, and proliferation. RAC1 has also been shown to be overexpressed in CRC. Despite evidence that RAC1 and its alternative splice isoform RAC1B play important roles in CRC and the pathways known to contribute to cetuximab resistance, there is a need to directly study the relationship between RAC1 and RAC1B and cetuximab resistance. This review highlights the recent studies investigating RAC1 and RAC1B in the context of CRC and suggests that these proteins could play a role in resistance to cetuximab.
结直肠癌(CRC)是美国诊断率最高的癌症之一,也是癌症相关死亡的主要原因。临床上,标准治疗方案包括手术、放疗和化疗;然而,针对CRC的靶向治疗的研发和临床应用一直在增加。不幸的是,许多患者对这些治疗产生耐药性。西妥昔单抗是首个被批准用于治疗晚期CRC的靶向治疗药物,它是一种单克隆抗体,靶向表皮生长因子受体并抑制下游信号通路激活,以限制肿瘤细胞的生长和增殖。CRC对西妥昔单抗的耐药性已得到充分研究,常见的耐药机制包括通过下游蛋白突变的组成型信号转导和上皮-间质转化的促进。虽然最常见的耐药机制是已知的,但仍有一部分患者通过未知机制产生耐药性。一种被预测与治疗耐药性有关的蛋白质是RAC1,它是一种小GTP酶,参与细胞骨架重排、细胞迁移、运动和增殖。RAC1在CRC中也被证明过表达。尽管有证据表明RAC1及其可变剪接异构体RAC1B在CRC以及已知导致西妥昔单抗耐药的信号通路中发挥重要作用,但仍需要直接研究RAC1和RAC1B与西妥昔单抗耐药性之间的关系。本综述重点介绍了最近在CRC背景下研究RAC1和RAC1B的研究,并表明这些蛋白质可能在对西妥昔单抗的耐药性中起作用。