[Regulation Mechanism of MTA3 in the Apoptosis of NSCLC Cells]

Reduced GRAMD1C expression correlates to poor prognosis and immune infiltrates in kidney renal clear cell carcinoma

There has been an increase in the mortality rate and morbidity of kidney cancer (KC) with kidney renal clear cell carcinoma (KIRC) being the most common subtype of KC. GRAMD1C (GRAM Domain Containing 1C) has not been reported to relate to prognosis and immunotherapy in any cancers. Using bioinformatics methods, we judged the prognostic value of GRAMD1C expression in KIRC and investigated the underlying mechanisms of GRAMD1C affecting the overall survival of KIRC based on data downloaded from The Cancer Genome Atlas (TCGA). The outcome revealed that reduced GRAMD1C expression could be a promising predicting factor of poor prognosis in kidney renal clear cell carcinoma. Meanwhile, GRAMDIC expression was significantly correlated to several tumor-infiltrating immune cells (TIICs), particularly the regulatory T cells (Tregs). Furthermore, GRAMD1C was most significantly associated with the mTOR signaling pathway, RNA degradation, WNT signaling pathway, toll pathway and AKT pathway in KIRC. Thus, GRAMD1C has the potential to become a novel predictor to evaluate prognosis and immune infiltration for KIRC patients.

MiR-367 regulates cell proliferation and metastasis by targeting metastasis-associated protein 3 (MTA3) in clear-cell renal cell carcinoma

Clear-cell renal cell carcinoma (ccRCC) is an aggressive and malignant kidney cancer which has the worst prognosis. Although microRNAs (miRNAs) have recently been identified as a novel class of regulators in oncogenesis and metastasis, there are few studies on their participation in ccRCC. In the present study, we observed that miR-367 expression was increased in both human ccRCC tissues and cell lines. Cell proliferation was evaluated by MTT assay and 5-Ethynyl-2′-deoxyuridine (EdU) assay kit, which indicated that inhibition of miR-367 could suppress the ccRCC proliferation. Forced expression of miR-367 substantially induced cell migration and invasion evidenced by wound-healing and transwell assays, and this carcinogenesis could be abolished by miR-367 inhibitor treatment. Further analysis identified Metastasis-Associated Protein 3 (MTA3) as a direct target of miR-367. QRT-PCR and western blot results indicated the correlative expression of miR-367 and MTA3 in ccRCC tissue samples. Overexpression of MTA3 reversed miR-367-induced cell proliferation, migration and invasion. Our data uncovered a novel molecular interaction between miR-367 and MTA3, indicating a therapeutic strategy of miR-367 for ccRCC.

[Effect and Mechanism of Radiosensitization of Poly (ADP-Ribose) Polymerase Inhibitor n Lewis Cells and Xenografts]

背景与目的

受电离辐射的肿瘤细胞DNA损伤主要为单链断裂(single strand break, SSB)与双链断裂(double strand break, DSB)，其中SSBs发生的频率数十倍于DSBs，而SSBs多能通过聚腺苷二磷酸核糖聚合酶[Poly(ADP-Ribose) polymerase, PARP]等因子进行修复。相关新药Olaparib(PARP1/PARP2/PARP3抑制剂)靶向作用于细胞SSBs损伤修复，其联合化疗的临床研究取得令人鼓舞结果。本实验旨在研究Olaparib对Lewis肺癌细胞及移植瘤放疗增敏作用，初步探讨其可能机制。

方法

采用MTT法检测Olaparib对Lewis细胞10%抑制浓度(10% inhibitory concentration, IC₁₀)值，克隆形成实验验证Olaparib联合放疗的体外增敏作用；成瘤小鼠分为空白对照、Olaparib、放疗(radiotherapy, RT, 2 Gy×5 d)、Olaparib+RT组，动态测量各组移植瘤体积变化；流式细胞术比较各组细胞体外凋亡率，TUNEL法比较移植瘤细胞凋亡；Western blot检测各组DNA损伤相关蛋白γH2AX，凋亡相关蛋白Bax/Bcl-2、Caspase-3表达。

结果

Olaparib对Lewis细胞IC₁₀值为4.4 μmol/L，克隆形成实验测得Olaparib放疗增敏比为1.211；移植瘤初体积(处理前)增长4倍所需天数，Olaparib+RT组显著高于单纯RT组(P < 0.001)；流式及TUNEL法检测Lewis细胞体内外凋亡率均Olaparib+RT组高于RT组(P < 0.05)；Olaparib+RT组细胞及移植瘤中γH2AX、Bax、Caspase-3显著高于RT组，Bcl-2显著低于RT组(均P < 0.05)。

结论

Olaparib对Lewis肺癌细胞及移植瘤起到显著放疗增敏作用，其机制可能与增加受照肿瘤细胞DNA双链断裂形成，上调Bax/Bcl-2促凋亡体系蛋白有关。