PAK6基因的克隆、抗体制备及在前列腺癌中的表达

Cloning of human PAK6 cDNA, preparation of anti-PAK6 polyclonal antibody and PAK6 expression in prostate cancer

目的在克隆P21相关激酶6(PAK6)全长cDNA的基础上,进一步克隆PAK6-N端基因并使其在大肠杆菌中高效表达,纯化基因产物并进行多克隆抗体制备,为研究PAK6与疾病的关系奠定基础。同时研究PAK6在前列腺癌中的表达。方法根据人全长PAK6cDNA序列,设计PCR引物,以人前列腺癌cDNA文库为模板利用PCR技术克隆PAK6全长cDNA。在此基础上,以PAK6全长cDNA为模板克隆PAK6-N端基因,将扩增产物克隆至大肠杆菌表达载体pGEX-4T-1中,经EcoRIXhoI双酶切鉴定后,进行DAN序列测定。GST-PAK6-N融合蛋白在硫代半乳糖苷(IPTG)诱导下在大肠杆菌BL21中得到表达。利用Glutothione亲和层析纯化融合蛋白,用纯化的GST-PAK6-N融合蛋白免疫家兔制备多克隆抗体,并用纯化的抗PAK6多克隆抗体在3例前列腺癌病人标本中进行了免疫组化表达的初步研究。结果成功克隆了PAK6全长cDNA和PAK6-N端基因片断,在E.coli中表达了PAK6-NT,纯化了GST-PAK6-N融合蛋白,并制备了PAK6特异性抗体。免疫组织化学研究表明:3例前列腺癌患者石蜡包埋病理组织切片免疫组化染色全部表现为间质阳性,PAK6在前列腺癌间质中呈现表达,而前列腺癌细胞则不染色。结论首次克隆了PAK6全长cDNA和PAK6-N端基因片断并成功制备了PAK6特异性抗体,为深入探讨PAK6在前列腺癌中的作用奠定了基础。

Objective To study the role of PAK6 in prostate cancer by cloning PAK6-N terminal sequence into E.coli and preparing its polyclonal rabbit antibody to detect PAK6 expression in prostate cancer. Methods Based on human PAK6 cDNA sequence, we designed a pair of primers to amplify the PAK6-N terminal sequence by PCR. The PCR product was subcloned into the bacterial expression vector pGEX-4T-1 via EcoRⅠ/XhoⅠ sites, and the recombinant plasmids were identified by enzymatic cleavage followed by DNA sequence analysis. By transforming the expression vector into component E.coli BL21 cells, the GST-PAK6-N fusion protein was expressed with IPTG induction. Glutathione-Sepharose beads were used to purify GST-PAK6-N fusion protein. Anti-PAK6 polyclonal antibody was produced by immunizing rabbits with purified GST-PAK6 N-terminal fusion protein. Anti-PAK6 polyclonal antibody was purified by protein A beads and used for detection of PAK6 expression in 3 prostate cancer specimens. Results and Conclusion We cloned PAK6-N terminal gene fragment successfully, purified GST-PAK6 N-terminal fusion protein, and obtained polyclonal rabbit PAK6 antibody. Immunohistochemistry indicated that PAK6 expressed in the stroma instead of the cancer cells in prostate cancer. All of the 3 postate cancer specimens showed positive staining in the stroma, suggesting that PAK6 may participate in the stroma-cancer cell interaction in prostate cancer.