利用转录组二代测序探索直肠癌术前放化疗的敏感性分子特征

Detection of preoperative chemoradiotherapy sensitivity molecular characteristics of rectal cancer by transcriptome second generation sequencing

目的:探索直肠癌新辅助放化疗的敏感性分子特征。方法:前瞻性收集局部进展期中、低位直肠癌30例患者的临床病理资料,包括一般情况、放化疗前影像学资料、放化疗前活组织病理检查资料、肿瘤分化程度等9项指标,分析其与直肠癌放化疗后肿瘤消退分级(tumor regression grading,TRG)的相关性。收集这30例患者新辅助治疗前结肠镜活检冰冻标本,进行转录组二代测序和生物信息学分析,筛选可能驱动直肠癌放化疗敏感性的基因。结果: 30例直肠癌患者中,病理完全缓解9例,部分缓解12例,缓解差9例。直肠癌放化疗后病理TRG缓解程度与肿瘤术前MRI的T分期呈负相关( P =0.046),与术前MRI直肠癌壁外血管侵犯(extramural vascular invasion, EMVI )呈正相关( P =0.003)。转录组二代测序对所获取的 P <0.05的217条转录本进行信号通路富集分析,可以发现多条与抗原呈递相关的细胞信号转导通路,其中HSPA1A、HSPA1B和EXOSC2的高表达和术后病理缓解差呈正相关( P <0.05),DNMBP、WASH8P、FAM57A和SGSM2等的高表达和术后病理缓解良好呈正相关( P <0.05)。结论:直肠癌术前MRI检测肿瘤EMVI阳性的患者放化疗后病理完全缓解率明显优于EMVI阴性者。HSPA1A、HSPA1B和EXOSC2高表达的患者术后病理缓解差,而DNMBP、WASH8P、FAM57A和SGSM2高表达的患者术后病理缓解良好。基于直肠癌放化疗敏感性分子特征,尝试阻断或增强与直肠癌放化疗敏感性相关的分子通路,可进一步探索能增加直肠癌放化疗敏感性的候选治疗靶点。

Objective: To detect the preoperative chemoradiotherapy sensitivity molecular characteristics of rectal cancer by transcriptome second generation sequencing. Methods: The clinicopathological data of 30 patients with locally advanced rectal cancer were collected prospectively, including 9 indicators (general conditions, imaging data before radiotherapy and chemotherapy, pathological data of biopsy before radiotherapy and chemotherapy, and tumor differentiation degree, etc .), in order to analyze the correlation between them and tumor regression grading (TRG) after radiotherapy and chemotherapy for rectal cancer. At the same time, frozen specimens of colonoscopy biopsy before neoadjuvant therapy were collected from these 30 patients, and transcriptome second-generation sequencing was performed for bioinformatics analysis to screen out the genes that might drive the radio chemotherapy sensitivity of rectal cancer . Results: Among the 30 patients with rectal cancer, 9 had complete pathological remission, 12 had partial remission, and 9 had poor remission. The degree of pathological TRG remission after radiotherapy and chemotherapy for rectal cancer was negatively correlated with the preoperative MRI T stage ( P = 0.046 ), and positively correlated with preoperative MRI rectal cancer extravascular invasion (EMVI)( P =0.003). Transcriptome second-generation sequencing of the obtained 217 transcripts ( P <0.05) for signal pathway enrichment analysis, and multiple cell signal transduction pathways related to antigen presentation could be found. The high expression of HSPA1A, HSPA1B and EXOSC2 was positively correlated with postoperative pathological remission ( P <0.05). The high expression of DNMBP, WASH8P, FAM57A, and SGSM2 was positively correlated with postoperative pathological remission ( P <0.05 ). Conclusion: Preoperative NMR detection of extra-tumoral vascular invasion (EMVI-positive) in patients with rectal cancer was significantly better than that of EMVI-negative patients after chemoradiotherapy. Patients with high expressions of HSPA1A, HSPA1B and EXOSC2 had poor postoperative pathological remission, while patients with high expressions of genes, such as DMNMB, WASH8P, FAM57A, and SGSM2 had good postoperative pathological remission. Based on the molecular characte- ristics of rectal cancer radiotherapy and chemotherapy, attempts to block or enhance the molecular pathways associated with chemosensitivity of rectal cancer, are to be made to further explore new candidate therapeutic targets that can increase the sensitivity of radiotherapy and chemotherapy for rectal cancer.