Overexpression of RhoA induces preneoplastic transformation of primary mammary epithelial cells

Xiangshan Zhao, Lin Lu, Nidhi Pokhriyal, Hui Ma, Lei Duan, Simon Lin, Nadereh Jafari, Hamid Band, Vimla Band

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Rho family small GTPases serve as molecular switches in the regulation of diverse cellular functions, including actin cytoskeleton remodeling, cell migration, gene transcription, and cell proliferation. Importantly, Rho overexpression is frequently seen in many carcinomas. However, published studies have almost invariably used immortal or tumorigenic cell lines to study Rho GTPase functions and there are no studies on the potential of Rho small GTPase to overcome senescence checkpoints and induce preneoplastic transformation of human mammary epithelial cells (hMEC). We show here that ectopic expression of wild-type (WT) RhoA as well as a constitutively active RhoA mutant (G14V) in two independent primary hMEC strains led to their immortalization and preneoplastic transformation. These cells have continued to grow over 300 population doublings (PD) with no signs of senescence, whereas cells expressing the vector or dominant-negative RhoA mutant (T19N) senesced after 20 PDs. Significantly, RhoA-T37A mutant, known to be incapable of interacting with many well-known Rho effectors including Rho kinase, PKN, mDia1, and mDia2, was also capable of immortalizing hMECs. Notably, similar to parental normal cells, Rho-immortalized cells have WT p53 and intact G1 cell cycle arrest on Adriamycin treatment. Rho-immortalized cells were anchorage dependent and were unable to form tumors when implanted in nude mice. Lastly, microarray expression profiling of Rho-immortalized versus parental cells showed altered expression of several genes previously implicated in immortalization and breast cancer progression. Taken together, these results show that RhoA can induce the preneoplastic transformation of hMECs by altering multiple pathways linked to cellular transformation and breast cancer.

Original languageEnglish (US)
Pages (from-to)483-491
Number of pages9
JournalCancer Research
Volume69
Issue number2
DOIs
StatePublished - Jan 15 2009

Fingerprint

Breast
Epithelial Cells
rho GTP-Binding Proteins
Monomeric GTP-Binding Proteins
Breast Neoplasms
G1 Phase Cell Cycle Checkpoints
rho-Associated Kinases
Cell Aging
Actin Cytoskeleton
Nude Mice
Doxorubicin
Cell Movement
Cell Proliferation
Carcinoma
Gene Expression
Cell Line
Population
Genes
Neoplasms

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

Cite this

Overexpression of RhoA induces preneoplastic transformation of primary mammary epithelial cells. / Zhao, Xiangshan; Lu, Lin; Pokhriyal, Nidhi; Ma, Hui; Duan, Lei; Lin, Simon; Jafari, Nadereh; Band, Hamid; Band, Vimla.

In: Cancer Research, Vol. 69, No. 2, 15.01.2009, p. 483-491.

Research output: Contribution to journalArticle

Zhao, Xiangshan ; Lu, Lin ; Pokhriyal, Nidhi ; Ma, Hui ; Duan, Lei ; Lin, Simon ; Jafari, Nadereh ; Band, Hamid ; Band, Vimla. / Overexpression of RhoA induces preneoplastic transformation of primary mammary epithelial cells. In: Cancer Research. 2009 ; Vol. 69, No. 2. pp. 483-491.
@article{d94c9f842d1c4d5e94b53a4f646ab72b,
title = "Overexpression of RhoA induces preneoplastic transformation of primary mammary epithelial cells",
abstract = "Rho family small GTPases serve as molecular switches in the regulation of diverse cellular functions, including actin cytoskeleton remodeling, cell migration, gene transcription, and cell proliferation. Importantly, Rho overexpression is frequently seen in many carcinomas. However, published studies have almost invariably used immortal or tumorigenic cell lines to study Rho GTPase functions and there are no studies on the potential of Rho small GTPase to overcome senescence checkpoints and induce preneoplastic transformation of human mammary epithelial cells (hMEC). We show here that ectopic expression of wild-type (WT) RhoA as well as a constitutively active RhoA mutant (G14V) in two independent primary hMEC strains led to their immortalization and preneoplastic transformation. These cells have continued to grow over 300 population doublings (PD) with no signs of senescence, whereas cells expressing the vector or dominant-negative RhoA mutant (T19N) senesced after 20 PDs. Significantly, RhoA-T37A mutant, known to be incapable of interacting with many well-known Rho effectors including Rho kinase, PKN, mDia1, and mDia2, was also capable of immortalizing hMECs. Notably, similar to parental normal cells, Rho-immortalized cells have WT p53 and intact G1 cell cycle arrest on Adriamycin treatment. Rho-immortalized cells were anchorage dependent and were unable to form tumors when implanted in nude mice. Lastly, microarray expression profiling of Rho-immortalized versus parental cells showed altered expression of several genes previously implicated in immortalization and breast cancer progression. Taken together, these results show that RhoA can induce the preneoplastic transformation of hMECs by altering multiple pathways linked to cellular transformation and breast cancer.",
author = "Xiangshan Zhao and Lin Lu and Nidhi Pokhriyal and Hui Ma and Lei Duan and Simon Lin and Nadereh Jafari and Hamid Band and Vimla Band",
year = "2009",
month = "1",
day = "15",
doi = "10.1158/0008-5472.CAN-08-2907",
language = "English (US)",
volume = "69",
pages = "483--491",
journal = "Cancer Research",
issn = "0008-5472",
publisher = "American Association for Cancer Research Inc.",
number = "2",

}

TY - JOUR

T1 - Overexpression of RhoA induces preneoplastic transformation of primary mammary epithelial cells

AU - Zhao, Xiangshan

AU - Lu, Lin

AU - Pokhriyal, Nidhi

AU - Ma, Hui

AU - Duan, Lei

AU - Lin, Simon

AU - Jafari, Nadereh

AU - Band, Hamid

AU - Band, Vimla

PY - 2009/1/15

Y1 - 2009/1/15

N2 - Rho family small GTPases serve as molecular switches in the regulation of diverse cellular functions, including actin cytoskeleton remodeling, cell migration, gene transcription, and cell proliferation. Importantly, Rho overexpression is frequently seen in many carcinomas. However, published studies have almost invariably used immortal or tumorigenic cell lines to study Rho GTPase functions and there are no studies on the potential of Rho small GTPase to overcome senescence checkpoints and induce preneoplastic transformation of human mammary epithelial cells (hMEC). We show here that ectopic expression of wild-type (WT) RhoA as well as a constitutively active RhoA mutant (G14V) in two independent primary hMEC strains led to their immortalization and preneoplastic transformation. These cells have continued to grow over 300 population doublings (PD) with no signs of senescence, whereas cells expressing the vector or dominant-negative RhoA mutant (T19N) senesced after 20 PDs. Significantly, RhoA-T37A mutant, known to be incapable of interacting with many well-known Rho effectors including Rho kinase, PKN, mDia1, and mDia2, was also capable of immortalizing hMECs. Notably, similar to parental normal cells, Rho-immortalized cells have WT p53 and intact G1 cell cycle arrest on Adriamycin treatment. Rho-immortalized cells were anchorage dependent and were unable to form tumors when implanted in nude mice. Lastly, microarray expression profiling of Rho-immortalized versus parental cells showed altered expression of several genes previously implicated in immortalization and breast cancer progression. Taken together, these results show that RhoA can induce the preneoplastic transformation of hMECs by altering multiple pathways linked to cellular transformation and breast cancer.

AB - Rho family small GTPases serve as molecular switches in the regulation of diverse cellular functions, including actin cytoskeleton remodeling, cell migration, gene transcription, and cell proliferation. Importantly, Rho overexpression is frequently seen in many carcinomas. However, published studies have almost invariably used immortal or tumorigenic cell lines to study Rho GTPase functions and there are no studies on the potential of Rho small GTPase to overcome senescence checkpoints and induce preneoplastic transformation of human mammary epithelial cells (hMEC). We show here that ectopic expression of wild-type (WT) RhoA as well as a constitutively active RhoA mutant (G14V) in two independent primary hMEC strains led to their immortalization and preneoplastic transformation. These cells have continued to grow over 300 population doublings (PD) with no signs of senescence, whereas cells expressing the vector or dominant-negative RhoA mutant (T19N) senesced after 20 PDs. Significantly, RhoA-T37A mutant, known to be incapable of interacting with many well-known Rho effectors including Rho kinase, PKN, mDia1, and mDia2, was also capable of immortalizing hMECs. Notably, similar to parental normal cells, Rho-immortalized cells have WT p53 and intact G1 cell cycle arrest on Adriamycin treatment. Rho-immortalized cells were anchorage dependent and were unable to form tumors when implanted in nude mice. Lastly, microarray expression profiling of Rho-immortalized versus parental cells showed altered expression of several genes previously implicated in immortalization and breast cancer progression. Taken together, these results show that RhoA can induce the preneoplastic transformation of hMECs by altering multiple pathways linked to cellular transformation and breast cancer.

UR - http://www.scopus.com/inward/record.url?scp=58349090028&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=58349090028&partnerID=8YFLogxK

U2 - 10.1158/0008-5472.CAN-08-2907

DO - 10.1158/0008-5472.CAN-08-2907

M3 - Article

C2 - 19147561

AN - SCOPUS:58349090028

VL - 69

SP - 483

EP - 491

JO - Cancer Research

JF - Cancer Research

SN - 0008-5472

IS - 2

ER -