Silencing of Rac3 inhibits proliferation and induces apoptosis of human lung cancer cells.

Tie-Qin Liu,Ge-Bang Wang,Zheng-Jun Li,Hong-Xu Liu,Xiang-Dong Tong

doi:10.7314/apjcp.2015.16.7.3061

Abstract

Rac3, a member of the Rac family of small guanosine triphosphatases (GTPases), regulates a variety of cell functions, including the organization of the cytoskeleton, cell migration, and invasion. Overexpression of Rac3 has been reported in several human cancers. However, the role of Rac3 in lung cancer (LC) has not been determined in detail. The purpose of this study was to investigate the effect of silencing of Rac3 expression in human LC cells and the consequences for cell survival. Lentivirus small hairpin RNA (shRNA) interference techniques were utilized to knock down the Rac3 gene. Gene and protein expression was quantified by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. LC cell apoptosis was examined by annexin V-APC /propidium iodide staining. Efficient silencing of Rac3 strongly inhibited A549 cell proliferation and colony formation ability, and significantly decreased tumor growth. Moreover, flow cytometry analysis showed that knockdown of Rac3 led to G2/M phase cell cycle arrest as well as an excess accumulation of cells in the G1 and S phase. Thus, functional analysis using shRNAs revealed a critical role for Rac3 in the tumor growth of LC cells. shRNA silencing of Rac3 could provide an effective strategy to treat LC.

Highlights

Rho-family guanosine triphosphatases (GTPases) are overexpressed in a variety of human cancer and possess a wide range of roles throughout the cell, including the regulation of cell migration and adhesion, mitosis, regulation of kinase activity, and regulation of transcription factors through cell signaling pathways (Baugher et al, 2005; Onesto et al, 2008)
Rac3 is highly expressed in lung cancer (LC) cell line phase and 19% are in the S phase of the cell cycle, while 66% of control infected cells are in the G0/G1 and 19% are in the S phase of the cell cycle (Figure 4A)
To investigate the function of Rac3 in LC, we evaluated cycle analysis revealed that the cell percentage in the the expression level of Rac3 in Non small cell lung cancer G1phase and S phase was increased while the cell numbers (NSCLC) cell line A549 by quantitative real-time polymerase chain reaction (qRT-PCR)

Summary

Introduction

Rho-family GTPases are overexpressed in a variety of human cancer and possess a wide range of roles throughout the cell, including the regulation of cell migration and adhesion, mitosis, regulation of kinase activity, and regulation of transcription factors through cell signaling pathways (Baugher et al, 2005; Onesto et al, 2008). Rac proteins are members of the Rho GTPase family and act as molecular switches in regulating a variety of biological response pathways, including cell motility, gene transcription, cell transformation, and cell-cycle progression (Haataja et al, 1997). The Rac family of GTPases consists of three members, Rac, the splice variant Rac1B, the hematopoietic-cell-specific Rac and the most recently described, Rac, which is strongly expressed in brain (Haataja et al, 1997). These proteins are highly homologous and differ in their transcriptional regulation and tissue distribution. Conclusions: functional analysis using shRNAs revealed a critical role for Rac in the tumor growth of LC cells. shRNA silencing of Rac could provide an effective strategy to treat LC

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