The Role of beta1 Integrin Subfamily in Anchorage-Dependent Apoptosis of Breast Carcinoma Cells Differing in Multidrug Resistance

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G. E. Morozevich¹, N. I. Kozlova¹, M. E. Preobrazhenskaya¹, N. A. Ushakova¹, I. A. Eltsov¹, A. A. Shtil², and A. E. Berman^1*

¹Orekhovich Institute of Biomedical Chemistry, Russian Academy of Medical Sciences, ul. Pogodinskaya 10, 119121 Moscow, Russia; fax: (7-495) 245-0857; E-mail: berman@ibmc.msk.ru

²Blokhin Russian Cancer Center, Russian Academy of Medical Sciences, Kashirskoe Shosse 24, 115478 Moscow, Russia

^* To whom correspondence should be addressed.

Received November 8, 2005; Revision received January 6, 2006

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Integrin expression was investigated in MCF-7 human breast adenocarcinoma line and in the MCF-7Dox line, which was selected from MCF-7 by a resistance to multiple antitumor drugs (MDR). We have shown that acquisition of MDR was accompanied by a drastically reduced expression of some integrins of the beta1-subfamily (alpha2beta1, alpha3beta1, alpha6beta1) and of alphavbeta5 intergin in the adenocarcinoma cells. In contrast, expression of alpha5beta1 integrin was markedly increased in the MDR cells. Along with multiple antitumor drug resistance, MCF-7Dox cells demonstrate elevated resistance to anchorage-dependent apoptosis (anoikis) and enhanced in vitro invasive activity. To elucidate the implication of beta1-integrins in the above phenotypic modifications, the effect of beta1-integrin signaling was assayed. Stimulation of beta1-mediated signaling was accomplished by treating of the cells with antibodies to the beta1-subunit common for members of the beta1-subfamily. These data show that activation of beta1-integrin signaling markedly upregulated anoikis of the adenocarcinoma cells.

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KEY WORDS: integrins, extracellular matrix, anoikis, metastasis, invasion

DOI: 10.1134/S000629790605004X

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