Translational Cancer Research Facility, National Center for Cancer Care and Research/Translational Research Institute, Hamad Medical Corporation, 2030, Doha, Qatar.
National Center for Cancer Care and Research, Hamad Medical Corporation, 2030, Doha, Qatar.
J Transl Med. 2023 Mar 31;21(1):235. doi: 10.1186/s12967-023-04073-y.
The mechanism of tumor immune escape and progression in colorectal cancer (CRC) is widely investigated in-vitro to help understand and identify agents that might play a crucial role in response to treatment and improve the overall survival of CRC patients. Several mechanisms of immune escape and tumor progression, including expression of stemness markers, inactivation of immunoregulatory genes by methylation, and epigenetic silencing, have been reported in CRC, indicating the potential of demethylating agents as anti-cancer drugs. Of these, a chemotherapeutic demethylating agent, Decitabine (DAC), has been reported to induce a dual effect on both DNA demethylation and histone changes leading to an increased expression of target biomarkers, thus making it an attractive anti-tumorigenic drug.
We compared the effect of DAC in primary 1076 Col and metastatic 1872 Col cell lines isolated and generated from patients' tumor tissues. Both cell lines were treated with DAC, and the expression of the NY-ESO-1 cancer-testis antigen, the PD-L1 immunoinhibitory marker, and the CD44, Nanog, KLF-4, CD133, MSI-1 stemness markers were analyzed using different molecular and immunological assays.
DAC treatment significantly upregulated stemness markers in both primary 1076 Col and meta-static 1872 Col cell lines, although a lower effect occurred on the latter: CD44 (7.85 fold; ***p = 0.0001 vs. (4.19 fold; *p = 0.0120), Nanog (4.1 fold; ***p < 0.0001 vs.1.69 fold; ***p = 0.0008), KLF-4 (4.33 fold; ***p < 0.0001 vs.2.48 fold; ***p = 0.0005), CD133 (16.77 fold; ***p = 0.0003 vs.6.36 fold; *p = 0.0166), and MSI-1 (2.33 fold; ***p = 0.0003 vs.2.3 fold; ***p = 0.0004), respectively. Interestingly, in the metastatic 1872 Col cells treated with DAC, the expression of both PD-L1 and NY-ESO-1 was increased tenfold (*p = 0.0128) and fivefold (***p < 0.0001), respectively.
We conclude that the upregulation of both stemness and immune checkpoint markers by DAC treatment on CRC cells might represent a mechanism of immune evasion. In addition, induction of NY-ESO-1 may represent an immuno-therapeutic option in metastatic CRC patients. Finally, the combination of DAC and anti-PD-1/anti-PD-L1 antibodies treatment should represent a potential therapeutic intervention for this group of patients.
在体外广泛研究结直肠癌（CRC）的肿瘤免疫逃逸和进展机制，以帮助理解和鉴定可能在治疗反应中发挥关键作用并改善 CRC 患者总体生存的药物。CRC 中已报道了多种免疫逃逸和肿瘤进展机制，包括干性标志物的表达、免疫调节基因的甲基化失活以及表观遗传沉默，这表明去甲基化药物作为抗癌药物的潜力。其中，一种化疗去甲基化药物地西他滨（DAC）已被报道对 DNA 去甲基化和组蛋白变化具有双重作用，导致靶标生物标志物的表达增加，从而使其成为一种有吸引力的抗肿瘤药物。
我们比较了 DAC 在从患者肿瘤组织中分离和生成的原发性 1076 Col 和转移性 1872 Col 细胞系中的作用。两种细胞系均用 DAC 处理，并使用不同的分子和免疫学检测分析 NY-ESO-1 癌症睾丸抗原、PD-L1 免疫抑制标记物以及 CD44、Nanog、KLF-4、CD133、MSI-1 干性标志物的表达。
DAC 处理显著上调了原发性 1076 Col 和转移性 1872 Col 细胞系中的干性标志物，尽管后者的效果较低：CD44（7.85 倍；***p = 0.0001 与 4.19 倍；*p = 0.0120）、Nanog（4.1 倍；***p < 0.0001 与 1.69 倍；***p = 0.0008）、KLF-4（4.33 倍；***p < 0.0001 与 2.48 倍；***p = 0.0005）、CD133（16.77 倍；***p = 0.0003 与 6.36 倍；*p = 0.0166）和 MSI-1（2.33 倍；***p = 0.0003 与 2.3 倍；***p = 0.0004）。有趣的是，在用 DAC 处理的转移性 1872 Col 细胞中，PD-L1 和 NY-ESO-1 的表达均增加了十倍（*p = 0.0128）和五倍（***p < 0.0001）。
我们得出结论，DAC 处理对 CRC 细胞中干性和免疫检查点标志物的上调可能代表一种免疫逃逸机制。此外，NY-ESO-1 的诱导可能代表转移性 CRC 患者的免疫治疗选择。最后，DAC 和抗 PD-1/抗 PD-L1 抗体治疗的联合应用应代表该患者群体的潜在治疗干预措施。
