Flavopiridol and trastuzumab synergistically inhibit proliferation of breast cancer cells: Association with selective cooperative inhibition of cyclin D1-dependent kinase and Akt signaling pathways

Kongming Wu, Chenguang Wang, Mark D'Amico, Richard J. Lee, Chris Albanese, Richard G. Pestell, Sridhar Mani

Research output: Contribution to journalArticle

60 Citations (Scopus)

Abstract

Cyclin D1 is essential for Neu-induced cell growth and is induced by growth factors through Ras-dependent and Ras-independent signaling pathways (1). Because flavopiridol, a novel flavanoid cyclin-cyclin-dependent kinase inhibitor, may function through Ras-dependent and/or -independent pathways, we hypothesized that treatment of breast cancer cells with inhibitors of Neu signaling and flavopiridol might synergize to inhibit proliferation. Human breast cancer cell lines, which express high levels of endogenous Neu receptor, were treated with the anti-Neu antibody, trastuzumab, together with flavopiridol and subject to MTT assay. Cell lines were assayed for alterations in cell cycle by fluorescence-activated cell sorter and signaling proteins by Western blot. Flavopiridol and trastuzumab synergistically inhibited DNA synthesis, cellular proliferation, and contact-dependent growth. Cytotoxic synergy was observed independent of the sequence of addition of the two drugs to cultured cells. In SKBR3 cells, a combination of trastuzumab and flavopiridol inhibited the Ras-MAPK-Akt pathway, decreased cyclin D1 abundance, and kinase activity to a greater extent than either drug alone. Compared with single-agent treatment, combination treatment selectively inhibited Akt and pRB phosphorylation. Cytotoxic synergy was observed with flavopiridol plus LY294002 (selective phosphatidylinositol 3-kinase inhibitor) but not with PD98059 (selective mitogen-activated protein kinase kinase 1 inhibitor) suggesting that Akt inhibition may be important in synergy. Zinc-induced overexpression of cyclin D1 in T-47D ΔMTcycD1 cells were more resistant to drug-induced cell death when compared with vector-transfected T-47D ΔMT cells. Cyclin D1 overexpression reverses drug treatment induced cell cycle arrest in SKBR3 cells. Flavopiridol and trastuzumab yield cytotoxic synergy in human breast cancer cells overexpressing Neu. Cyclin D1 overexpression results in combination drug resistance. In addition, inhibition of Akt may prove to be a useful therapeutic strategy in combination with flavopiridol.

Original languageEnglish (US)
Pages (from-to)695-706
Number of pages12
JournalMolecular Cancer Therapeutics
Volume1
Issue number9
StatePublished - Jul 2002

Fingerprint

alvocidib
Cyclin-Dependent Kinases
Cyclin D1
Breast Neoplasms
Pharmaceutical Preparations
MAP Kinase Kinase 1
ErbB-2 Receptor
Phosphatidylinositol 3-Kinase
Cell Line
2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
Cyclins
Trastuzumab
Growth
Cell Cycle Checkpoints
Drug Resistance

ASJC Scopus subject areas

  • Oncology
  • Cancer Research
  • Drug Discovery
  • Pharmacology

Cite this

Flavopiridol and trastuzumab synergistically inhibit proliferation of breast cancer cells : Association with selective cooperative inhibition of cyclin D1-dependent kinase and Akt signaling pathways. / Wu, Kongming; Wang, Chenguang; D'Amico, Mark; Lee, Richard J.; Albanese, Chris; Pestell, Richard G.; Mani, Sridhar.

In: Molecular Cancer Therapeutics, Vol. 1, No. 9, 07.2002, p. 695-706.

Research output: Contribution to journalArticle

@article{c613a16705ba4a26ae73b828c9a00967,
title = "Flavopiridol and trastuzumab synergistically inhibit proliferation of breast cancer cells: Association with selective cooperative inhibition of cyclin D1-dependent kinase and Akt signaling pathways",
abstract = "Cyclin D1 is essential for Neu-induced cell growth and is induced by growth factors through Ras-dependent and Ras-independent signaling pathways (1). Because flavopiridol, a novel flavanoid cyclin-cyclin-dependent kinase inhibitor, may function through Ras-dependent and/or -independent pathways, we hypothesized that treatment of breast cancer cells with inhibitors of Neu signaling and flavopiridol might synergize to inhibit proliferation. Human breast cancer cell lines, which express high levels of endogenous Neu receptor, were treated with the anti-Neu antibody, trastuzumab, together with flavopiridol and subject to MTT assay. Cell lines were assayed for alterations in cell cycle by fluorescence-activated cell sorter and signaling proteins by Western blot. Flavopiridol and trastuzumab synergistically inhibited DNA synthesis, cellular proliferation, and contact-dependent growth. Cytotoxic synergy was observed independent of the sequence of addition of the two drugs to cultured cells. In SKBR3 cells, a combination of trastuzumab and flavopiridol inhibited the Ras-MAPK-Akt pathway, decreased cyclin D1 abundance, and kinase activity to a greater extent than either drug alone. Compared with single-agent treatment, combination treatment selectively inhibited Akt and pRB phosphorylation. Cytotoxic synergy was observed with flavopiridol plus LY294002 (selective phosphatidylinositol 3-kinase inhibitor) but not with PD98059 (selective mitogen-activated protein kinase kinase 1 inhibitor) suggesting that Akt inhibition may be important in synergy. Zinc-induced overexpression of cyclin D1 in T-47D ΔMTcycD1 cells were more resistant to drug-induced cell death when compared with vector-transfected T-47D ΔMT cells. Cyclin D1 overexpression reverses drug treatment induced cell cycle arrest in SKBR3 cells. Flavopiridol and trastuzumab yield cytotoxic synergy in human breast cancer cells overexpressing Neu. Cyclin D1 overexpression results in combination drug resistance. In addition, inhibition of Akt may prove to be a useful therapeutic strategy in combination with flavopiridol.",
author = "Kongming Wu and Chenguang Wang and Mark D'Amico and Lee, {Richard J.} and Chris Albanese and Pestell, {Richard G.} and Sridhar Mani",
year = "2002",
month = "7",
language = "English (US)",
volume = "1",
pages = "695--706",
journal = "Molecular Cancer Therapeutics",
issn = "1535-7163",
publisher = "American Association for Cancer Research Inc.",
number = "9",

}

TY - JOUR

T1 - Flavopiridol and trastuzumab synergistically inhibit proliferation of breast cancer cells

T2 - Association with selective cooperative inhibition of cyclin D1-dependent kinase and Akt signaling pathways

AU - Wu, Kongming

AU - Wang, Chenguang

AU - D'Amico, Mark

AU - Lee, Richard J.

AU - Albanese, Chris

AU - Pestell, Richard G.

AU - Mani, Sridhar

PY - 2002/7

Y1 - 2002/7

N2 - Cyclin D1 is essential for Neu-induced cell growth and is induced by growth factors through Ras-dependent and Ras-independent signaling pathways (1). Because flavopiridol, a novel flavanoid cyclin-cyclin-dependent kinase inhibitor, may function through Ras-dependent and/or -independent pathways, we hypothesized that treatment of breast cancer cells with inhibitors of Neu signaling and flavopiridol might synergize to inhibit proliferation. Human breast cancer cell lines, which express high levels of endogenous Neu receptor, were treated with the anti-Neu antibody, trastuzumab, together with flavopiridol and subject to MTT assay. Cell lines were assayed for alterations in cell cycle by fluorescence-activated cell sorter and signaling proteins by Western blot. Flavopiridol and trastuzumab synergistically inhibited DNA synthesis, cellular proliferation, and contact-dependent growth. Cytotoxic synergy was observed independent of the sequence of addition of the two drugs to cultured cells. In SKBR3 cells, a combination of trastuzumab and flavopiridol inhibited the Ras-MAPK-Akt pathway, decreased cyclin D1 abundance, and kinase activity to a greater extent than either drug alone. Compared with single-agent treatment, combination treatment selectively inhibited Akt and pRB phosphorylation. Cytotoxic synergy was observed with flavopiridol plus LY294002 (selective phosphatidylinositol 3-kinase inhibitor) but not with PD98059 (selective mitogen-activated protein kinase kinase 1 inhibitor) suggesting that Akt inhibition may be important in synergy. Zinc-induced overexpression of cyclin D1 in T-47D ΔMTcycD1 cells were more resistant to drug-induced cell death when compared with vector-transfected T-47D ΔMT cells. Cyclin D1 overexpression reverses drug treatment induced cell cycle arrest in SKBR3 cells. Flavopiridol and trastuzumab yield cytotoxic synergy in human breast cancer cells overexpressing Neu. Cyclin D1 overexpression results in combination drug resistance. In addition, inhibition of Akt may prove to be a useful therapeutic strategy in combination with flavopiridol.

AB - Cyclin D1 is essential for Neu-induced cell growth and is induced by growth factors through Ras-dependent and Ras-independent signaling pathways (1). Because flavopiridol, a novel flavanoid cyclin-cyclin-dependent kinase inhibitor, may function through Ras-dependent and/or -independent pathways, we hypothesized that treatment of breast cancer cells with inhibitors of Neu signaling and flavopiridol might synergize to inhibit proliferation. Human breast cancer cell lines, which express high levels of endogenous Neu receptor, were treated with the anti-Neu antibody, trastuzumab, together with flavopiridol and subject to MTT assay. Cell lines were assayed for alterations in cell cycle by fluorescence-activated cell sorter and signaling proteins by Western blot. Flavopiridol and trastuzumab synergistically inhibited DNA synthesis, cellular proliferation, and contact-dependent growth. Cytotoxic synergy was observed independent of the sequence of addition of the two drugs to cultured cells. In SKBR3 cells, a combination of trastuzumab and flavopiridol inhibited the Ras-MAPK-Akt pathway, decreased cyclin D1 abundance, and kinase activity to a greater extent than either drug alone. Compared with single-agent treatment, combination treatment selectively inhibited Akt and pRB phosphorylation. Cytotoxic synergy was observed with flavopiridol plus LY294002 (selective phosphatidylinositol 3-kinase inhibitor) but not with PD98059 (selective mitogen-activated protein kinase kinase 1 inhibitor) suggesting that Akt inhibition may be important in synergy. Zinc-induced overexpression of cyclin D1 in T-47D ΔMTcycD1 cells were more resistant to drug-induced cell death when compared with vector-transfected T-47D ΔMT cells. Cyclin D1 overexpression reverses drug treatment induced cell cycle arrest in SKBR3 cells. Flavopiridol and trastuzumab yield cytotoxic synergy in human breast cancer cells overexpressing Neu. Cyclin D1 overexpression results in combination drug resistance. In addition, inhibition of Akt may prove to be a useful therapeutic strategy in combination with flavopiridol.

UR - http://www.scopus.com/inward/record.url?scp=0036632965&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0036632965&partnerID=8YFLogxK

M3 - Article

C2 - 12479366

AN - SCOPUS:0036632965

VL - 1

SP - 695

EP - 706

JO - Molecular Cancer Therapeutics

JF - Molecular Cancer Therapeutics

SN - 1535-7163

IS - 9

ER -