Wu Peng-Fei, Gao Wei-Wei, Sun Cui-Lan, Ma Tai, Hao Ji-Qing
Department of Oncology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022, China.
Chin Med J (Engl). 2020 Jun 5;133(11):1304-1311. doi: 10.1097/CM9.0000000000000823.
Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), such as erlotinib and gefitinib, are widely used to treat non-small cell lung cancer (NSCLC). However, acquired resistance is unavoidable, impairing the anti-tumor effects of EGFR-TKIs. It is reported that histone deacetylase (HDAC) inhibitors could enhance the anti-tumor effects of other antineoplastic agents and radiotherapy. However, whether the HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) can overcome erlotinib-acquired resistance is not fully clear.
An erlotinib-resistant PC-9/ER cell line was established through cell maintenance in a series of erlotinib-containing cultures. NSCLC cells were co-cultured with SAHA, erlotinib, or their combination, and then the viability of cells was measured by the 3-(4,5-Dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and apoptosis was determined by flow cytometry and western blotting. Finally, the expression of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) was assessed by western blotting.
The half-maximal inhibitory concentration of parental PC-9 cells was significantly lower than the established erlotinib-acquired resistant PC-9/ER cell line. PC-9/ER cells demonstrated reduced expression of PTEN compared with PC-9 and H1975 cells, and the combination of SAHA and erlotinib significantly inhibited cell growth and increased apoptosis in both PC-9/ER and H1975 cells. Furthermore, treating PC-9/ER cells with SAHA or SAHA combined with erlotinib significantly upregulated the expression of PTEN mRNA and protein compared with erlotinib treatment alone.
PTEN deletion is closely related to acquired resistance to EGFR-TKIs, and treatment with the combination of SAHA and erlotinib showed a greater inhibitory effect on NSCLC cells than single-drug therapy. SAHA enhances the suppressive effects of erlotinib in lung cancer cells, increasing cellular apoptosis and PTEN expression. SAHA can be a potential adjuvant to erlotinib treatment, and thus, can improve the efficacy of NSCLC therapy.
表皮生长因子受体（EGFR）酪氨酸激酶抑制剂（TKIs），如厄洛替尼和吉非替尼，被广泛用于治疗非小细胞肺癌（NSCLC）。然而，获得性耐药不可避免，会削弱EGFR-TKIs的抗肿瘤作用。据报道，组蛋白脱乙酰酶（HDAC）抑制剂可增强其他抗肿瘤药物和放疗的抗肿瘤作用。然而，HDAC抑制剂辛二酰苯胺异羟肟酸（SAHA）是否能克服厄洛替尼获得性耐药尚不完全清楚。
通过在一系列含厄洛替尼的培养基中培养细胞，建立了厄洛替尼耐药的PC-9/ER细胞系。将NSCLC细胞与SAHA、厄洛替尼或它们的组合共培养，然后通过3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四氮唑溴盐法测定细胞活力，并通过流式细胞术和蛋白质印迹法测定细胞凋亡。最后，通过蛋白质印迹法评估10号染色体上缺失的磷酸酶和张力蛋白同源物（PTEN）的表达。
亲本PC-9细胞的半数最大抑制浓度显著低于建立的厄洛替尼获得性耐药PC-9/ER细胞系。与PC-9和H1975细胞相比，PC-9/ER细胞中PTEN的表达降低，SAHA和厄洛替尼的组合显著抑制PC-9/ER和H1975细胞的生长并增加细胞凋亡。此外，与单独使用厄洛替尼治疗相比，用SAHA或SAHA与厄洛替尼联合处理PC-9/ER细胞显著上调PTEN mRNA和蛋白的表达。
PTEN缺失与EGFR-TKIs的获得性耐药密切相关，SAHA和厄洛替尼联合治疗对NSCLC细胞的抑制作用比单药治疗更大。SAHA增强了厄洛替尼对肺癌细胞的抑制作用，增加了细胞凋亡和PTEN表达。SAHA可以作为厄洛替尼治疗的潜在佐剂，从而提高NSCLC治疗的疗效。
