Division of Medical Biochemistry and Structural Biology, Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, SAMRC/UCT Gynaecological Cancer Research Centre, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
Division of Medical Biochemistry and Structural Biology, Faculty of Health Sciences, University of Cape Town, Observatory, Cape Town, 7925, South Africa.
BMC Cancer. 2018 Nov 16;18(1):1123. doi: 10.1186/s12885-018-5044-8.
Karyopherin β1 (Kpnβ1) is the main nuclear import protein involved in the transport of cargoes from the cytoplasm into the cell nucleus. Previous research has found Kpnβ1 to be significantly overexpressed in cervical cancer and other cancer tissues, and further studies showed that inhibition of Kpnβ1 expression by siRNA resulted in cancer cell death, while non-cancer cells were minimally affected. These results suggest that Kpnβ1 has potential as an anticancer therapeutic target, thus warranting further research into the association between Kpnβ1 expression and cancer progression. Here, the biological effects associated with Kpnβ1 overexpression were investigated in order to further elucidate the relationship between Kpnβ1 and the cancer phenotype.
To evaluate the effect of Kpnβ1 overexpression on cell biology, cell proliferation, cell cycle, cell morphology and cell adhesion assays were performed. To determine whether Kpnβ1 overexpression influences cell sensitivity to chemotherapeutic agents like Cisplatin, cell viability assays were performed. Expression levels of key proteins were analysed by Western blot analysis.
Our data revealed that Kpnβ1 overexpression, above that which was already detected in cancer cells, resulted in reduced proliferation of cervical cancer cells. Likewise, normal epithelial cells showed reduced proliferation after Kpnβ1 overxpression. Reduced cancer cell proliferation was associated with a delay in cell cycle progression, as well as changes in the morphology and adhesion properties of cells. Additionally, Kpnβ1 overexpressing HeLa cells exhibited increased sensitivity to cisplatin, as shown by decreased cell viability and increased apoptosis, where p53 and p21 inhibition reduced and enhanced cell sensitivity to Cisplatin, respectively.
Overall, our results suggest that a tight balance of Kpnβ1 expression is required for cellular function, and that perturbation of this balance results in negative effects associated with a variety of biological processes.
核孔蛋白β1（Kpnβ1）是一种主要的核输入蛋白，参与将细胞质中的货物运入细胞核。先前的研究发现，Kpnβ1 在宫颈癌和其他癌症组织中显著过表达，进一步的研究表明，通过 siRNA 抑制 Kpnβ1 的表达会导致癌细胞死亡，而对非癌细胞的影响很小。这些结果表明，Kpnβ1 可能成为一种抗癌治疗靶点，因此需要进一步研究 Kpnβ1 表达与癌症进展之间的关系。在这里，研究了与 Kpnβ1 过表达相关的生物学效应，以进一步阐明 Kpnβ1 与癌症表型之间的关系。
为了评估 Kpnβ1 过表达对细胞生物学的影响，进行了细胞增殖、细胞周期、细胞形态和细胞黏附测定。为了确定 Kpnβ1 过表达是否影响顺铂等化疗药物对细胞的敏感性，进行了细胞活力测定。通过 Western blot 分析分析了关键蛋白的表达水平。
我们的数据表明，Kpnβ1 过表达（超过已在癌细胞中检测到的水平）导致宫颈癌细胞增殖减少。同样，正常上皮细胞在 Kpnβ1 过表达后增殖减少。癌细胞增殖减少与细胞周期进程的延迟以及细胞形态和黏附特性的变化有关。此外，Kpnβ1 过表达的 HeLa 细胞对顺铂的敏感性增加，表现为细胞活力降低和细胞凋亡增加，其中 p53 和 p21 抑制分别降低和增强了细胞对顺铂的敏感性。
总的来说，我们的结果表明，Kpnβ1 表达的平衡对于细胞功能是必需的，而这种平衡的破坏会导致与各种生物学过程相关的负面效应。
