HPV16癌基因E7调控头颈鳞癌增殖和侵袭转移的机制研究

HPV-positive head and neck squamous cell carcinoma (HNSCC) shows special clinical features, such as rapid proliferation, strong invasion and earlier lymph node metastasis, however, the mechanism is still unknown, which is possibly related to the regulation of virogene E7.Previsou studies found that there was a higher level expression of miRNA-106a in HPV-positive HNSCC, and RUNX3 was closely related with tumor proliferation, invasion and migration. Moreover, the miRNA targets-prediction analysis indicated that RUNX3 was a possible target-gene of miRNA-106a. As mentioned above, we speculate that E7 could regulate miRNA-106a expression by affecting DGCR8, and miRNA-106a could regulate proliferation and migration of HPV-positive HNSCC via targeting RUNX3 and downstream signaling pathway. In this research, we focus on the E7/miRNA-106a/RUNX3 regulation axis, taking HNSCC tissues, HPV-positive HNSCC cell lines, and xenografts as the study objects, we aim to explore the relationships between E7, DGCR8, miRNA-106a and RUNX3 as well as their effects on tumor proliferation and migration, through changing the expression of these molecules by gene transfection and (or) RNA inference. In summary, this research aims not only to demonstrate the regulation mechanism, but to provide evidence of target-therapy involving miRNA-106a, which is expected to improve the clinical prognosis of HNSCC.

HPV阳性头颈鳞癌侵袭性强，淋巴结转移早，可能与病毒癌基因E7的调控相关，具体机制尚不明确。前期研究发现，miRNA-106a在HPV阳性头颈鳞癌中表达较高，而RUNX3与肿瘤增殖和侵袭转移密切相关，靶基因预测RUNX3是miRNA-106a可能的靶基因。故提出科研假设：HPV16癌基因E7通过DGCR8调控miRNA-106a的表达，miRNA-106a则通过靶基因RUNX3及下游通路调控头颈鳞癌的增殖和侵袭转移。本研究从E7/miRNA-106a/RUNX3调控轴切入，以肿瘤组织、HPV阳性头颈鳞癌细胞株及其荷瘤动物作为研究对象，采用基因转染和（或）RNA干扰改变E7、DGCR8、miRNA-106a和RUNX3等的表达水平，探讨上述分子之间的调控关系及对头颈鳞癌增殖和侵袭转移的影响。本课题不仅研究调控机制，并为围绕miRNA-106a展开的靶向治疗提供依据，以期提高头颈鳞癌的预后。

HPV阳性头颈鳞癌侵袭性强，淋巴结转移早，可能与病毒癌基因E7的调控相关，具体机制尚不明确。在前期研究基础上，本课题提出科研假设：病毒基因E7通过DGCR8正向调控miRNA-106a的表达，进而通过下游靶基因调控HPV阳性头颈鳞癌的生物学特性。本课题以E7/miRNA-106a/RUNX3调控轴为研究主线，以HPV阳性头颈鳞癌组织、头颈鳞癌细胞、荷瘤动物为研究对象，研究HPV16 癌基因E7对肿瘤增殖侵袭能力的影响，主要包含两个方面，即：（1）HPV16 E7通过DGCR8调控miRNA-106a的表达；（2）miRNA-106a通过靶基因RUNX3及其下游通路（TGF-β通路）调控头颈鳞癌的侵袭性。本课题完成了项目计划的内容，包括：（1）头颈鳞癌组织标本中 E7、DGCR8、miRNA-106a、RUNX3和TGF-β的表达；（2）细胞实验验证E7通过DGCR8调控miRNA-106a的表达；（3）在头颈鳞癌细胞中验证miRNA-106a通过RUNX3及TGF-β调控增殖与侵袭能力；（4）动物模型实验中进一步验证 E7/miRNA-106a/RUNX3之间的调控关系。本课题的重要结果是：组织标本实验提示miRNA-106a 在HPV阳性头颈鳞癌中的表达明显高于HPV 阴性头颈鳞癌；靶基因预测发现RUNX3可能是miRNA-106a 的靶基因；病毒基因E7通过上调DGCR8正向调控miRNA-106a的表达，而miRNA-106a则通过靶基因RUNX3增强 HPV阳性头颈鳞癌的增殖、迁移和侵袭能力，抑制了其凋亡。本课题的科学意义是，本研究阐述了HPV阳性头颈鳞癌增殖、迁移、侵袭、凋亡的调控机制，特别是从HPV癌基因通过调控miRNA表达方面来调控头颈鳞癌的生物学特性，这是本研究项目最大的贡献，本研究证实在头颈鳞癌中，miRNA-106a作为与临床预后相关的分子标记物，具有一定的临床应用前景，也为后续开展针对miRNA-106a 的个体化、靶向治疗提供依据。