Caveolin-1 and accelerated host aging in the breast tumor microenvironment: Chemoprevention with rapamycin, an mTOR inhibitor and anti-aging drug

Isabelle Mercier, Jeanette Camacho, Kanani Titchen, Donna M. Gonzales, Kevin Quann, Kelly G. Bryant, Alexander Molchansky, Janet N. Milliman, Diana Whitaker-Menezes, Federica Sotgia, Jean François Jasmin, Roland Schwarting, Richard G. Pestell, Mikhail V. Blagosklonny, Michael P. Lisanti

Research output: Contribution to journalArticlepeer-review

95 Citations (Scopus)

Abstract

Increasing chronological age is the most significant risk factor for human cancer development. To examine the effects of host aging on mammary tumor growth, we used caveolin (Cav)-1 knockout mice as a bona fide model of accelerated host aging. Mammary tumor cells were orthotopically implanted into these distinct microenvironments (Cav-1 +/+ versus Cav-1 -/- age-matched young female mice). Mammary tumors grown in a Cav-1-deficient tumor microenvironment have an increased stromal content, with vimentin-positive myofibroblasts (a marker associated with oxidative stress) that are also positive for S6-kinase activation (a marker associated with aging). Mammary tumors grown in a Cav-1-deficient tumor microenvironment were more than fivefold larger than tumors grown in a wild-type microenvironment. Thus, a Cav-1-deficient tumor microenvironment provides a fertile soil for breast cancer tumor growth. Interestingly, the mammary tumor-promoting effects of a Cav-1-deficient microenvironment were estrogen and progesterone independent. In this context, chemoprevention was achieved by using the mammalian target of rapamycin (mTOR) inhibitor and anti-aging drug, rapamycin. Systemic rapamycin treatment of mammary tumors grown in a Cav-1-deficient microenvironment significantly inhibited their tumor growth, decreased their stromal content, and reduced the levels of both vimentin and phospho-S6 in Cav-1-deficient cancer-associated fibroblasts. Since stromal loss of Cav-1 is a marker of a lethal tumor microenvironment in breast tumors, these high-risk patients might benefit from treatment with mTOR inhibitors, such as rapamycin or other rapamycin-related compounds (rapalogues).

Original languageEnglish
Pages (from-to)278-293
Number of pages16
JournalAmerican Journal of Pathology
Volume181
Issue number1
DOIs
Publication statusPublished - Jul 2012
Externally publishedYes

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