Cancer Biology Research Program, University of Arizona, Tucson, Arizona.
Department of Pathology, University of Arizona, Tucson, Arizona.
Cancer Res. 2019 Sep 15;79(18):4703-4714. doi: 10.1158/0008-5472.CAN-19-0868. Epub 2019 Jul 23.
Human prostate cancer confined to the gland is indolent (low-risk), but tumors outside the capsule are aggressive (high-risk). Extracapsular extension requires invasion within and through a smooth muscle-structured environment. Because integrins respond to biomechanical cues, we used a gene editing approach to determine if a specific region of laminin-binding α6β1 integrin was required for smooth muscle invasion both and . Human tissue specimens showed prostate cancer invasion through smooth muscle and tumor coexpression of α6 integrin and E-cadherin in a cell-cell location and α6 integrin in a cell-extracellular matrix (ECM) distribution. Prostate cancer cells expressing α6 integrin (DU145 α6WT) produced a 3D invasive network on laminin-containing Matrigel and invaded into smooth muscle both and . In contrast, cells without α6 integrin (DU145 α6KO) and cells expressing an integrin mutant (DU145 α6AA) did not produce invasive networks, could not invade muscle both and , and surprisingly formed 3D cohesive clusters. Using electric cell-substrate impedance testing, cohesive clusters had up to a 30-fold increase in normalized resistance at 400 Hz (cell-cell impedance) as compared with the DU145 α6WT cells. In contrast, measurements at 40,000 Hz (cell-ECM coverage) showed that DU145 α6AA cells were two-fold decreased in normalized resistance and were defective in restoring resistance after a 1 μmol/L S1P challenge as compared with the DU145 α6WT cells. The results suggest that gene editing of a specific α6 integrin extracellular region, not required for normal tissue function, can generate a new biophysical cancer phenotype unable to invade the muscle, presenting a new therapeutic strategy for metastasis prevention in prostate cancer. SIGNIFICANCE: This study shows an innovative strategy to block prostate cancer metastasis and invasion in the muscle through gene editing of a specific α6 integrin extracellular region.
人类局限于前列腺腺体的前列腺癌是惰性的（低风险），但包膜外的肿瘤具有侵袭性（高风险）。包膜外延伸需要在平滑肌结构环境中进行侵袭。由于整合素对生物力学线索做出反应，我们使用基因编辑方法来确定层粘连蛋白结合α6β1 整合素的特定区域是否需要通过平滑肌侵袭 和 。人类组织标本显示，前列腺癌通过平滑肌侵袭，肿瘤在细胞-细胞位置和细胞外基质（ECM）分布中共同表达α6 整合素和 E-钙粘蛋白。表达α6 整合素的前列腺癌细胞（DU145α6WT）在含有层粘连蛋白的 Matrigel 上产生了 3D 侵袭网络，并在 和 时侵入平滑肌。相比之下，没有α6 整合素的细胞（DU145α6KO）和表达整合素突变体的细胞（DU145α6AA）无法形成侵袭网络，既不能侵入肌肉 和 ，而且令人惊讶的是形成了 3D 凝聚簇。使用电细胞-基底阻抗测试，凝聚簇在 400Hz（细胞-细胞阻抗）时的归一化电阻增加了多达 30 倍，而 DU145α6WT 细胞则增加了 30 倍。相比之下，在 40000Hz（细胞-ECM 覆盖）时的测量结果表明，与 DU145α6WT 细胞相比，DU145α6AA 细胞的归一化电阻降低了两倍，并且在 1μmol/L S1P 挑战后恢复电阻的能力受损。结果表明，对特定α6 整合素细胞外区域进行基因编辑，而不影响正常组织功能，可以产生一种新的生物物理癌症表型，无法侵袭肌肉，为预防前列腺癌转移提供了一种新的治疗策略。意义：本研究通过基因编辑特定的α6 整合素细胞外区域，展示了一种阻止前列腺癌在肌肉中转移和侵袭的创新策略。
