Spagnardi Marzia, Paredes Jenny, Zabaleta Jovanny, Garai Jone, Reyes Tiana, Martello Laura A, Williams Jennie L
Department of Medicine, Division of Gastroenterology and Hepatology, SUNY Downstate Health Sciences University, Brooklyn, NY, United States.
Department of Interdisciplinary Oncology, Louisiana State University Health Sciences Center, New Orleans, LA, United States.
Front Oncol. 2022 Dec 1;12:1010380. doi: 10.3389/fonc.2022.1010380. eCollection 2022.
In the U.S., African Americans (AAs) present with the highest incidence and mortality rates for Colorectal Cancer (CRC). When compared to Caucasian American (CA) patients, AAs also have reduced response to the first line standard of care chemotherapeutic agent 5-Fluorouracil (5-FU). Previously, we observed differential gene expression between the two populations, suggesting that colon tumors from AA patients display a decreased antitumor immune response and an increased expression of genes encoding proteins involved in inflammatory processes, such as Interleukin-1β (IL-1β). Here, we investigate the role of IL-1β in modifying chemotherapeutic response and altering expression of proteins in novel AA and well-established CA colon cancer cell lines.
RNA sequencing analysis was performed to detect expression of genes involved in inflammation in AA and CA colon cancer cells. The effects of IL-1β on 5-FU response was evaluated by assessing cell viability (MTS assay) and apoptosis (flow cytometry analysis) following treatment with 5-FU alone or in combination with the cytokine. Further, we used an IL-1 receptor antagonist (IL-1Ra) to inhibit IL-1β-induced effects on 5-FU sensitivity and NF-kB pathway activation.
AA colon cancer cell lines present significant increase in expression of genes (373-fold change (FC), 3.24 FC), , (5.33 FC) (5.95 FC), , (3.72 FC), (161 FC), (4.1 FC). A significant decrease in the response to 5-FU treatment, as well as a significant increase in phosphorylation of IκBα and secretion of IL-8, was seen following IL-1β treatment, in both AA and CA cell lines. Finally, treatment with IL-1Ra was able to reverse the effects induced by IL-1β, by increasing the cells sensitivity to 5-FU. IL-1Ra also inhibited phosphorylation of IκBα and IL-8 secretion.
Our results suggest a differential expression of inflammatory genes and proteins that might regulate the different response to IL-1β between AA and CA colon cancer cell lines. Our data also demonstrates that IL-1β is involved in modulating 5-FU response in both AA and CA colon cancer cell lines. Further investigation of these mechanisms might help elucidate the differences seen in incidence, mortality and response to therapy in AA colon cancer patients.
在美国，非裔美国人（AA）的结直肠癌（CRC）发病率和死亡率最高。与美国白人（CA）患者相比，AA患者对一线标准护理化疗药物5-氟尿嘧啶（5-FU）的反应也较差。此前，我们观察到这两个人群之间存在基因表达差异，这表明AA患者的结肠肿瘤显示出抗肿瘤免疫反应降低，以及参与炎症过程的蛋白质编码基因表达增加，如白细胞介素-1β（IL-1β）。在此，我们研究IL-1β在改变新型AA和成熟CA结肠癌细胞系的化疗反应及蛋白质表达中的作用。
进行RNA测序分析以检测AA和CA结肠癌细胞中参与炎症的基因表达。通过评估单独使用5-FU或与细胞因子联合处理后的细胞活力（MTS测定）和凋亡（流式细胞术分析），来评估IL-1β对5-FU反应的影响。此外，我们使用IL-1受体拮抗剂（IL-1Ra）来抑制IL-1β对5-FU敏感性和NF-κB途径激活的诱导作用。
AA结肠癌细胞系中基因 （373倍变化（FC），3.24 FC）、 （5.33 FC）、 （5.95 FC）、 、 （3.72 FC）、 （161 FC）、 （4.1 FC）的表达显著增加。在AA和CA细胞系中，IL-1β处理后，5-FU治疗反应显著降低，IκBα磷酸化和IL-8分泌显著增加。最后，用IL-1Ra治疗能够通过增加细胞对5-FU的敏感性来逆转IL-1β诱导的作用。IL-1Ra还抑制IκBα磷酸化和IL-8分泌。
我们的结果表明炎症基因和蛋白质的差异表达可能调节AA和CA结肠癌细胞系对IL-1β的不同反应。我们的数据还表明IL-1β参与调节AA和CA结肠癌细胞系中的5-FU反应。对这些机制的进一步研究可能有助于阐明AA结肠癌患者在发病率、死亡率和治疗反应方面的差异。
