Ghoshal Archita, Ghosh Siddhartha Sankar
Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 39, India.
Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam, 39, India.
Mol Cell Biochem. 2016 Jul;418(1-2):119-35. doi: 10.1007/s11010-016-2738-6. Epub 2016 Jun 23.
The Wnt signaling pathway plays a predominant role in aberrant proliferation in myriad of cancers. In non-cancerous cells, Wnts are blocked by the secreted frizzled-related proteins (sFRPs) that are generally downregulated in cancer cells. We have purified and characterized bacterially expressed glutathione S-transferase-tagged SFRP4 from a novel clone generated from human cell origin. Cervical cancer (HeLa) and lung cancer (A549) cells, in which Wnt and associated genes were found to be expressed, were treated with the purified recombinant sFRP4, which revealed a significant dose-dependent cell growth inhibition up to 40 %. The current investigation on functionality of this bacterially produced recombinant sFRP4 in arresting cancer cell proliferation is the first of its kind, where G2/M phase arrest and early apoptosis were evident. Increase in phosphorylated β-catenin in sFRP4 treatment indicated inhibition of Wnt pathway, which was further confirmed by downregulation of pro-proliferative genes, namely cyclin D1, c-myc, and survivin. Functional activity of recombinant sFRP4 was further exploited in co-therapy module with chemotherapeutic drugs to decipher molecular events. Collectively, our study on purified recombinant sFRP4 from bacterial host holds great promise in targeting Wnt signaling for exploring new strategies to combat cancer.
Wnt信号通路在众多癌症的异常增殖中起主要作用。在非癌细胞中，Wnts被分泌型卷曲相关蛋白（sFRPs）所阻断，而sFRPs在癌细胞中通常下调。我们从源自人类细胞的新克隆中纯化并鉴定了细菌表达的谷胱甘肽S-转移酶标记的SFRP4。用纯化的重组sFRP4处理发现表达Wnt及相关基因的宫颈癌（HeLa）和肺癌（A549）细胞，结果显示高达40%的显著剂量依赖性细胞生长抑制。目前关于这种细菌产生的重组sFRP4在抑制癌细胞增殖方面功能的研究尚属首次，其中G2/M期阻滞和早期凋亡明显。sFRP4处理后磷酸化β-连环蛋白增加表明Wnt信号通路受到抑制，这通过增殖相关基因即细胞周期蛋白D1、c-myc和生存素的下调得到进一步证实。重组sFRP4的功能活性在与化疗药物的联合治疗模块中进一步得到利用，以解读分子事件。总的来说，我们对从细菌宿主中纯化的重组sFRP4的研究在靶向Wnt信号以探索对抗癌症的新策略方面具有很大的前景。
