title: Inhibition of mycobacterial infection by the tumor suppressor PTEN.
abstract: The tumor suppressor PTEN is a lipid phosphatase that is frequently mutated in various human cancers. PTEN suppresses tumor cell proliferation, survival, and growth mainly by inhibiting the PI3K-Akt signaling pathway through dephosphorylation of phosphatidylinositol 3,4,5-triphosphate. In addition to it role in tumor suppression, the PTEN-PI3K pathway controls many cellular functions, some of which may be important for cellular resistance to infection. Currently, the intersection between tumorigenic signaling pathways and cellular susceptibility to infection is not well defined. In this study we report that PTEN signaling regulates infection of both noncancerous and cancerous cells by multiple intracellular mycobacterial pathogens and that pharmacological modulation of PTEN signaling can affect mycobacterial infection. We found that PTEN deficiency renders multiple types of cells hyper-susceptible to infection by Mycoplasma and Mycobacterium bovis Bacillus Calmette-Guérin (BCG). The lipid phosphatase activity of PTEN is required for attenuating infection. Furthermore, we found mycobacterial infection activates host cell Akt phosphorylation, and pharmacological inhibition of Akt or PI3K activity reduced levels of intracellular infection. Intriguingly, inhibition of mTOR, one of the downstream components of the Akt signaling and a promising cancer therapeutic target, also lowered intracellular Bacillus Calmette-Guérin levels in mammary epithelial cancer MCF-7 cells. These findings demonstrate a critical role of PTEN-regulated pathways in pathogen infection. The relationship of PTEN-PI3K-Akt mTOR status and susceptibility to mycobacterial infection suggests that the interaction of mycobacterial pathogens with cancer cells may be influenced by genetic alterations in the tumor cells.
authors.affiliation: Cell Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA.
authors.forename: Guochang
authors.initials: G
authors.lastname: Huang
authors.forename: Gil
authors.initials: G
authors.lastname: Redelman-Sidi
authors.forename: Neal
authors.initials: N
authors.lastname: Rosen
authors.forename: Michael S
authors.initials: MS
authors.lastname: Glickman
authors.forename: Xuejun
authors.initials: X
authors.lastname: Jiang
mesh_terms: D001943:Breast Neoplasms; D005260:Female; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006801:Humans; D008297:Male; D009163:Mycobacterium bovis / Q000254:growth & development / Q000378:metabolism*; D009175:Mycoplasma Infections / Q000378:metabolism; D009369:Neoplasms / Q000378:metabolism / Q000382:microbiology*; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011471:Prostatic Neoplasms; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D014376:Tuberculosis / Q000378:metabolism*; D001749:Urinary Bladder Neoplasms
chemical_list: D051059:PTEN Phosphohydrolase; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; C546842:MTOR protein, human; C494918:AKT1 protein, human; C494929:PTEN protein, human