Felt Sébastien A, Droby Gaith N, Grdzelishvili Valery Z
Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina, USA.
Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina, USA
J Virol. 2017 Jul 27;91(16). doi: 10.1128/JVI.00461-17. Print 2017 Aug 15.
Vesicular stomatitis virus (VSV) is a promising oncolytic virus (OV). Although VSV is effective against a majority of pancreatic ductal adenocarcinoma cell (PDAC) cell lines, some PDAC cell lines are highly resistant to VSV, and the mechanisms of resistance are still unclear. JAK1/2 inhibitors (such as ruxolitinib and JAK inhibitor I) strongly stimulate VSV replication and oncolysis in all resistant cell lines but only partially improve the susceptibility of resistant PDACs to VSV. VSV tumor tropism is generally dependent on the permissiveness of malignant cells to viral replication rather than on receptor specificity, with several ubiquitously expressed cell surface molecules playing a role in VSV attachment to host cells. However, as VSV attachment to PDAC cells has never been tested before, here we examined if it was possibly inhibited in resistant PDAC cells. Our data show a dramatically weaker attachment of VSV to HPAF-II cells, the most resistant human PDAC cell line. Although sequence analysis of low-density lipoprotein (LDL) receptor (LDLR) mRNA did not reveal any amino acid substitutions in this cell line, HPAF-II cells displayed the lowest level of LDLR expression and dramatically lower LDL uptake. Treatment of cells with various statins strongly increased LDLR expression levels but did not improve VSV attachment or LDL uptake in HPAF-II cells. However, LDLR-independent attachment of VSV to HPAF-II cells was dramatically improved by treating cells with Polybrene or DEAE-dextran. Moreover, combining VSV with ruxolitinib and Polybrene or DEAE-dextran successfully broke the resistance of HPAF-II cells to VSV by simultaneously improving VSV attachment and replication. Oncolytic virus (OV) therapy is an anticancer approach that uses viruses that selectively infect and kill cancer cells. This study focuses on oncolytic vesicular stomatitis virus (VSV) against pancreatic ductal adenocarcinoma (PDAC) cells. Although VSV is effective against most PDAC cells, some are highly resistant to VSV, and the mechanisms are still unclear. Here we examined if VSV attachment to cells was inhibited in resistant PDAC cells. Our data show very inefficient attachment of VSV to the most resistant human PDAC cell line, HPAF-II. However, VSV attachment to HPAF-II cells was dramatically improved by treating cells with polycations. Moreover, combining VSV with polycations and ruxolitinib (which inhibits antiviral signaling) successfully broke the resistance of HPAF-II cells to VSV by simultaneously improving VSV attachment and replication. We envision that this novel triple-combination approach could be used in the future to treat PDAC tumors that are highly resistant to OV therapy.
水泡性口炎病毒（VSV）是一种很有前景的溶瘤病毒（OV）。尽管VSV对大多数胰腺导管腺癌（PDAC）细胞系有效，但一些PDAC细胞系对VSV具有高度抗性，且抗性机制仍不清楚。JAK1/2抑制剂（如鲁索替尼和JAK抑制剂I）在所有抗性细胞系中强烈刺激VSV复制和溶瘤作用，但仅部分提高抗性PDAC对VSV的敏感性。VSV的肿瘤嗜性通常取决于恶性细胞对病毒复制的允许性，而非受体特异性，一些普遍表达的细胞表面分子在VSV附着于宿主细胞中发挥作用。然而，由于此前从未测试过VSV与PDAC细胞的附着情况，在此我们研究了它在抗性PDAC细胞中是否可能受到抑制。我们的数据显示VSV与HPAF-II细胞（最具抗性的人PDAC细胞系）的附着显著减弱。尽管低密度脂蛋白（LDL）受体（LDLR）mRNA的序列分析未揭示该细胞系中有任何氨基酸替换，但HPAF-II细胞显示出最低水平的LDLR表达以及显著更低的LDL摄取。用各种他汀类药物处理细胞可强烈提高LDLR表达水平，但并未改善HPAF-II细胞中VSV的附着或LDL摄取。然而，用聚凝胺或DEAE-葡聚糖处理细胞可显著改善VSV不依赖LDLR与HPAF-II细胞的附着。此外，将VSV与鲁索替尼以及聚凝胺或DEAE-葡聚糖联合使用，通过同时改善VSV附着和复制成功打破了HPAF-II细胞对VSV的抗性。溶瘤病毒（OV）疗法是一种抗癌方法，使用能选择性感染并杀死癌细胞的病毒。本研究聚焦于溶瘤水泡性口炎病毒（VSV）对胰腺导管腺癌（PDAC）细胞的作用。尽管VSV对大多数PDAC细胞有效，但一些细胞对VSV具有高度抗性，且机制仍不清楚。在此我们研究了VSV与抗性PDAC细胞的附着是否受到抑制。我们的数据显示VSV与最具抗性的人PDAC细胞系HPAF-II的附着效率极低。然而，用聚阳离子处理细胞可显著改善VSV与HPAF-II细胞的附着。此外，将VSV与聚阳离子和鲁索替尼（抑制抗病毒信号传导）联合使用，通过同时改善VSV附着和复制成功打破了HPAF-II细胞对VSV的抗性。我们设想这种新型三联组合方法未来可用于治疗对OV疗法高度抗性的PDAC肿瘤。
