ShRNA-based POLD2 expression knockdown sensitizes glioblastoma to DNA-Damaging therapeutics

Qingfu Xu; Chengchen Hu; Yan Zhu; Kimberly Wang; Bachuchu Lal; Lichao Li; Junhai Tang; Shuang Wei; Guohao Huang; Shuli Xia; Shengqing Lv; John Laterra; Yugang Jiang; Yunqing Li

doi:10.1016/j.canlet.2020.01.011

ShRNA-based POLD2 expression knockdown sensitizes glioblastoma to DNA-Damaging therapeutics

Cancer Lett. 2020 Jul 10:482:126-135. doi: 10.1016/j.canlet.2020.01.011. Epub 2020 Jan 16.

Authors

Qingfu Xu¹, Chengchen Hu², Yan Zhu³, Kimberly Wang⁴, Bachuchu Lal⁴, Lichao Li⁵, Junhai Tang⁶, Shuang Wei⁴, Guohao Huang⁶, Shuli Xia², Shengqing Lv⁶, John Laterra⁷, Yugang Jiang⁸, Yunqing Li⁹

Affiliations

¹ Department of Neurosurgery, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, 510623, PR China; Department of Neurosurgery, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, PR China; Hugo W. Moser Research Institute at Kennedy Krieger, 707 N. Broadway, Baltimore, MD, 21205, USA; Department of Neurology, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD, 21287, USA.
² Hugo W. Moser Research Institute at Kennedy Krieger, 707 N. Broadway, Baltimore, MD, 21205, USA; Department of Neurology, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD, 21287, USA.
³ Department of Ultrasonography, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, 510623, PR China; Department of Obstetrics and Gynecology, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, PR China.
⁴ Hugo W. Moser Research Institute at Kennedy Krieger, 707 N. Broadway, Baltimore, MD, 21205, USA.
⁵ Department of Neurosurgery, The First Hospital of Lanzhou University, Lanzhou, Gansu, 730000, PR China.
⁶ Department of Neurosurgery, Third Military Medical University, Chongqing, 400037, PR China.
⁷ Hugo W. Moser Research Institute at Kennedy Krieger, 707 N. Broadway, Baltimore, MD, 21205, USA; Department of Neurology, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD, 21287, USA; Department of Oncology, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD, 21287, USA; Department of Neuroscience, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD, 21287, USA.
⁸ Department of Neurosurgery, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, PR China.
⁹ Hugo W. Moser Research Institute at Kennedy Krieger, 707 N. Broadway, Baltimore, MD, 21205, USA; Department of Neurology, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD, 21287, USA. Electronic address: liyu@kennedykrieger.org.

Abstract

Glioblastoma (GBM) has limited therapeutic options. DNA repair mechanisms contribute GBM cells to escape therapies and re-establish tumor growth. Multiple studies have shown that POLD2 plays a critical role in DNA replication, DNA repair and genomic stability. We demonstrate for the first time that POLD2 is highly expressed in human glioma specimens and that expression correlates with poor patient survival. siRNA or shRNA POLD2 inhibited GBM cell proliferation, cell cycle progression, invasiveness, sensitized GBM cells to chemo/radiation-induced cell death and reversed the cytoprotective effects of EGFR signaling. Conversely, forced POLD2 expression was found to induce GBM cell proliferation, colony formation, invasiveness and chemo/radiation resistance. POLD2 expression associated with stem-like cell subsets (CD133⁺ and SSEA-1⁺ cells) and positively correlated with Sox2 expression in clinical specimens. Its expression was induced by Sox2 and inhibited by the forced differentiation of GBM neurospheres. shRNA-POLD2 modestly inhibited GBM neurosphere-derived orthotopic xenografts growth, when combined with radiation, dramatically inhibited xenograft growth in a cooperative fashion. These novel findings identify POLD2 as a new potential therapeutic target for enhancing GBM response to current standard of care therapeutics.

Keywords: Chemo-/radiation; Cytoprotective oncogene; GBM stem-like cells; POLD2; Sensitizer.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Animals
Brain Neoplasms / genetics
Brain Neoplasms / metabolism
Brain Neoplasms / therapy*
Cell Line, Tumor
Cell Movement / drug effects
Cell Movement / radiation effects
Cell Proliferation / drug effects
Cell Proliferation / radiation effects
DNA Polymerase III / antagonists & inhibitors
DNA Polymerase III / genetics*
DNA Polymerase III / metabolism*
Drug Synergism
Gene Expression Regulation, Neoplastic / drug effects
Gene Expression Regulation, Neoplastic / radiation effects
Glioblastoma / genetics
Glioblastoma / metabolism
Glioblastoma / therapy*
Humans
Mice
Neoplastic Stem Cells / drug effects
Neoplastic Stem Cells / metabolism
Neoplastic Stem Cells / radiation effects
RNA, Small Interfering / administration & dosage*
RNA, Small Interfering / pharmacology
Radiotherapy
Survival Analysis
Temozolomide / administration & dosage*
Temozolomide / therapeutic use
Up-Regulation* / drug effects
Up-Regulation* / radiation effects
Xenograft Model Antitumor Assays

Substances

RNA, Small Interfering
POLD2 protein, human
DNA Polymerase III
Temozolomide

Abstract

Publication types

MeSH terms

Substances

Grants and funding