蛋白激酶D在口腔鳞癌细胞生态位重建和适应中的作用和机制

During the past decade, it has become increasingly recognized that the biological behavior of tumor cells are completely different from normal cells with characteristics of fast growth and dynamic material & energy metabolism. The establishment of tumor ecology theory provides us a new way to expound the abnormal biological behavior of tumor cells. From an ecological perspective, one can look at this process as a new species (cancer cells), which have different metabolic and reproductive strategies compared with the "resident" population (somatic cells) to invade a new habitat (tissue). A right cancerous clone at the right place, the right time successful invasion will result in the formation of a primary solid tumor. Once a tumor is formed, cancer cells reconstruction their microenvironment (tumor niche) by changing pH through glycolysis, secreting growth factors and recruiting tumor-associated macrophages to promote cell growth, activating fibroblasts, evading predation from immune system, et al. Protein kinase D is a novel family of serine/threonine kinases. Evidence has established that specific PKD isoforms are dysregulated in several cancer types, and PKD involvement has been documented in a variety of cellular processes important to cancer development, including cell growth, apoptosis, motility, and angiogenesis. Our previous researches have shown that PKD2 could mediate multi-drug resistance in breast cancer cells through modulation of P-glycoprotein expression. The expression and activation of PKD2 was positive relate to the chemotherapeutic drugs resistance. PKD2 also play an important role in interferon- - induced PD-L1 surface expression and PD-L1 meditated oral squamous carcinoma immune evasion. Inhibition the activation of PKD2 not only inhibits PD-L1 expression and promotes an anti-tumor effect, but also decreases drug resistance in chemotherapy. Base on the function of PKD and our previous result and the tumor ecology theory. We supposed that PKD play an important role in tumor niche reconstruction & adaptation of oral squamous carcinoma. The further investigation will focus on the role of PKD in the secretion of lactic acid, glycolysis-related enzyme activity, the expression of apoptosis-related protein and immune suppression-related protein, the autophagy behavior of oral squamous carcinoma cells, by Western blot, RNA interference, metabolomics, protein chips and other technology. This project integrates oncology, cell biology and ecology. Interpret the molecular mechanisms of abnormal biological behavior of oral squamous carcinoma cells from ecological perspective. It is very important to clarify abnormal biological behavior of tumor cells and explore new technologies, new methods of oral squamous carcinoma treatment.

口腔鳞癌细胞是一群生长和代谢等生物学行为完全不同于正常组织细胞的异质性群体。从生态学角度：口腔鳞癌的形成类似于一个新物种（肿瘤细胞）对正常口腔黏膜组织生态位的入侵。为了生存和发展，肿瘤细胞入侵后，重建了一个其赖以生存的缺氧、酸性、耐药和逃逸"猎食者""捕食"的"居住"微环境- - -口腔鳞癌生态位。课题拟在前期研究发现"蛋白激酶D2（PKD2）在肿瘤多药耐药形成和免疫逃逸中发挥了重要的作用"的基础上，设想PKD参与了口腔鳞癌细胞生态位重建和适应过程。进一步采用Western blot、RNA干扰、代谢组学、蛋白芯片等技术，系统分析PKD家族成员在口腔鳞癌细胞生态位重建和适应中糖酵解相关酶活化、乳酸分泌、自噬行为、凋亡，免疫抑制相关蛋白表达中的作用和机制。以期从生态学角度解读口腔鳞癌细胞生态微环境形成的分子机制，探索口腔鳞癌治疗新技术、新方法、新靶点。

口腔鳞癌细胞是一群生长和代谢等生物学行为完全不同于正常组织细胞的异质性群体。从生态学角度：口腔鳞癌的形成类似于一个新物种（肿瘤细胞）对正常口腔黏膜组织生态位的入侵。为了生存和发展，肿瘤细胞入侵后，重建了一个其赖以生存的缺氧、酸性、耐药和逃逸“猎食者”“捕食”的“居住”微环境---口腔鳞癌生态位。课题在分析口腔肿瘤细胞中PKD家族表达情况基础上，进一步通过RNA干扰或基因转染，改变PKD在口腔肿瘤细胞中表达后，分析PKD在口腔中肿瘤生态位重建和适应中的作用。结果发现：1.PKD家族在不同来源肿瘤细胞中表达活化程度存在显著差异。其中PKD1在高侵袭性口腔肿瘤细胞株SCC-LM等，以及发生淋巴结转移肿瘤病人癌组织中高表达和活化。2.PKD1通过调控糖代谢相关酶，促进肿瘤细胞缺氧糖酵解，葡萄糖摄取和乳酸分泌，促进肿瘤酸性微环境重建；3.PKD1通过调控自噬蛋白表达，促进肿瘤细胞酸性微环境条件下自噬和适应。4.PKD1通过调控肿瘤凋亡相关蛋白表达，促进肿瘤生长和抑制肿瘤凋亡；5. PKD1通过调控化疗药物诱导的p-gp表达从而参与肿瘤细胞MDR形成；6.PKD3通过调控单核细胞向肿瘤相关巨噬细胞分化和肿瘤细胞膜表面免疫抑制蛋白PD-L1表达，促进肿瘤免疫逃逸微环境形成和肿瘤免疫逃逸。研究结果表明：PKD家族在口腔肿瘤微环境重建和适应中发挥重要作用。靶向PKD家族是肿瘤生物治疗潜在靶点，但同时也表明，在肿瘤微环境重建和适应中，不同PKD家族成员发挥不同效应，在把向治疗中需要特别关注。