Depletion of Paraspeckle Protein 1 Enhances Methyl Methanesulfonate-Induced Apoptosis through Mitotic Catastrophe

PLoS One. 2016 Jan 19;11(1):e0146952. doi: 10.1371/journal.pone.0146952. eCollection 2016.

Abstract

Previously, we have shown that paraspeckle protein 1 (PSPC1), a protein component of paraspeckles that was involved in cisplatin-induced DNA damage response (DDR), probably functions at the G1/S checkpoint. In the current study, we further examined the role of PSPC1 in another DNA-damaging agent, methyl methanesulfonate (MMS)-induced DDR, in particular, focusing on MMS-induced apoptosis in HeLa cells. First, it was found that MMS treatment induced the expression of PSPC1. While MMS treatment alone can induce apoptosis, depletion of PSPC1 expression using siRNA significantly increased the level of apoptosis following MMS exposure. In contrast, overexpressing PSPC1 decreased the number of apoptotic cells. Interestingly, morphological observation revealed that many of the MMS-treated PSPC1-knockdown cells contained two or more nuclei, indicating the occurrence of mitotic catastrophe. Cell cycle analysis further showed that depletion of PSPC1 caused more cells entering the G2/M phase, a prerequisite of mitosis catastrophe. On the other hand, over-expressing PSPC1 led to more cells accumulating in the G1/S phase. Taken together, these observations suggest an important role for PSPC1 in MMS-induced DDR, and in particular, depletion of PSPC1 can enhance MMS-induced apoptosis through mitotic catastrophe.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents, Alkylating / pharmacology*
  • Apoptosis
  • Cell Proliferation / drug effects
  • Cell Survival / drug effects
  • DNA Damage
  • HeLa Cells
  • Humans
  • Methyl Methanesulfonate / pharmacology*
  • Mitosis / drug effects*
  • Nuclear Proteins / genetics*
  • Nuclear Proteins / metabolism
  • RNA, Small Interfering / metabolism
  • RNA-Binding Proteins / genetics*
  • RNA-Binding Proteins / metabolism

Substances

  • Antineoplastic Agents, Alkylating
  • Nuclear Proteins
  • PSPC1 protein, human
  • RNA, Small Interfering
  • RNA-Binding Proteins
  • Methyl Methanesulfonate

Grants and funding

JY is a recipient of the Zhejiang Provincial Program for the Cultivation of High-level Innovative Health Talents. This work was funded by National Natural Science Foundation of China (Nos. 81172692, 81373036, 81472961, 81302398, 81502752, http://npd.nsfc.gov.cn/fundingProjectSearchAction!search.action), Zhejiang Provincial Department of Science and Technology (2013C14016, http://www.zjkjt.gov.cn/news/node01/detail0101/2013/0101_47060.htm), Zhejiang Provincial Department of Education (Y201328971), Hangzhou City Commission of Science and Technology (20130633B27, http://220.191.210.97:8080/WebHall/WebIndex.aspx), Ministry of Science and Technology of the People's Republic of China (2009DFB30390, http://finance.most.gov.cn/), National Health and Family Planning Commission of China (No. WKJ2014-ZJ-0, http://www.zjmed.org.cn/previewerlet.do?id=D4A9C5F17379B886F94E42A9BF39BB32), Postdoctoral Science Foundation of China (520000-X91504, http://jj.chinapostdoctor.org.cn/V1/Program1/Default.aspx) and Fundamental Research Funds for the Central Universities (2014QNA7021). The funder (Zhejiang CONBA Pharmaceutical Co. Ltd.) provided support in the form of salaries for author YLS, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of YLS are articulated in the ‘author contributions’ section.