Unit of Cellular Networks and Molecular Therapeutic Targets, IRCCS Regina Elena National Cancer Institute, I‑00144 Rome, Italy.
Pathology Division, IRCCS Regina Elena National Cancer Institute, I‑00144 Rome, Italy.
Oncol Rep. 2021 Mar;45(3):899-910. doi: 10.3892/or.2020.7912. Epub 2020 Dec 24.
Colorectal cancer (CRC) is the third most frequently diagnosed type of cancer worldwide. Stage II CRC accounts for ~25% all CRC cases and their management after surgical resection remains a clinical dilemma due to the lack of reliable criteria for identifying patients who may benefit from adjuvant chemotherapy. Homeodomain‑interacting protein kinase 2 (HIPK2), a multifunctional kinase involved in numerous signaling pathways, serves several key roles in cell response to different types of stresses, including chemotherapy‑induced genotoxic damage. In the present study, immunohistochemistry was performed for HIPK2 on a tissue microarray of primary human tumor samples from 84 patients with stage II CRC, treated (30 patients) or not treated (54 patients) with adjuvant chemotherapy, and sequenced for the TP53 gene, a key HIPK2 target in genotoxic damage response. It was observed that, regardless of the TP53 gene status, a high percentage of HIPK2+ cells was associated with therapeutic vulnerability in stage II CRC, suggesting a contribution of HIPK2 to drug‑response in vivo. For the in vitro characterization, HIPK2 was depleted in human CRC cells by CRISPR/Cas9 or RNA interference. HIPK2‑proficient and HIPK2‑defective cells were evaluated for their response to 5‑fluorouracil (5‑FU) and oxaliplatin (OXA). The results revealed that HIPK2 depletion induced resistance to 5‑FU and OXA, and that this resistance was not overcome by brusatol, an inhibitor of the antioxidant response regulator nuclear factor erythroid 2‑related factor 2 (NRF2), which is frequently overexpressed in CRC. By contrast, cell sensitivity to 5‑FU and OXA was further induced by brusatol supplementation in HIPK2‑proficient cells, further supporting the contribution of HIPK2 in chemotherapy response. Overall, the present results suggested that HIPK2 may be a potential predictive marker for adjuvant‑treated stage II CRC and for prospective therapy with NRF2 modulators.
结直肠癌（CRC）是全球最常见的第三大癌症类型。II 期 CRC 约占所有 CRC 病例的 25%，由于缺乏识别可能受益于辅助化疗的患者的可靠标准，其手术后的管理仍然是一个临床难题。同源域相互作用蛋白激酶 2（HIPK2）是一种参与多种信号通路的多功能激酶，在细胞对不同类型应激的反应中发挥着几个关键作用，包括化疗诱导的遗传毒性损伤。在本研究中，对 84 例 II 期 CRC 患者的原发性人肿瘤样本组织微阵列进行了 HIPK2 的免疫组织化学分析，这些患者接受（30 例）或未接受（54 例）辅助化疗，并对 TP53 基因进行了测序，TP53 基因是遗传毒性损伤反应中 HIPK2 的关键靶点。结果观察到，无论 TP53 基因状态如何，HIPK2+细胞的高比例与 II 期 CRC 的治疗易感性相关，提示 HIPK2 对体内药物反应的贡献。为了进行体外特征分析，通过 CRISPR/Cas9 或 RNA 干扰使人类 CRC 细胞中的 HIPK2 缺失。评估了 HIPK2 功能正常和缺陷的细胞对 5-氟尿嘧啶（5-FU）和奥沙利铂（OXA）的反应。结果表明，HIPK2 缺失诱导对 5-FU 和 OXA 的耐药性，而用抗氧化反应调节剂核因子红细胞 2 相关因子 2（NRF2）抑制剂布立司他不能克服这种耐药性，NRF2 在 CRC 中经常过表达。相比之下，在 HIPK2 功能正常的细胞中补充布立司他进一步诱导了细胞对 5-FU 和 OXA 的敏感性，进一步支持了 HIPK2 在化疗反应中的作用。总体而言，本研究结果表明，HIPK2 可能是辅助治疗 II 期 CRC 的潜在预测标志物，也是 NRF2 调节剂的潜在治疗靶点。
