Connexin43 increases the sensitivity of prostate cancer cells to TNFalpha-induced apoptosis.
To examine the effects of increased expression of connexin43 (Cx43) upon cell viability and response to cytotoxic agents, we expressed Cx43 in LNCaP and PC3 prostate cancer cells by infection with a recombinant adenovirus (Ad-Cx43). Infection with Ad-Cx43 led to the formation of Cx43-containing gap junction plaques at appositional membranes and increased Lucifer Yellow transfer in LNCaP cells, but not in PC3 cells. The increased intercellular communication was blocked by co-infection with an adenovirus containing a dominant-negative Cx43 (Ad-Cx43DN). Infection of LNCaP (but not PC3) cells with Ad-Cx43 greatly increased their sensitivity to killing by tumor necrosis factor alpha (TNFalpha), anti-Fas antibodies, and TRAIL as quantified using an MTS assay. The TNFalpha-induced cell death was dependent on cell density, and it was associated with increased annexin V staining, an increased proportion of sub-G1 cells, and activation of caspase 8. The TNFalpha-induced effects on Ad-Cx43-infected LNCaP cells were blocked by co-infection with Ad-Cx43DN or by pre-incubation with neutralizing antibodies directed against TNFalpha receptor 1. These results demonstrate that TNFalpha induces apoptosis in LNCaP cells by signaling through TNFalpha receptor 1 and that expression of functional Cx43 gap junction channels increases their sensitivity to TNFalpha.
Wang
Min
M
Department of Pediatrics, Section of Hematology/Oncology and Stem Cell Transplantation, University of Chicago, Chicago, IL 60637, USA.
Berthoud
Viviana M
VM
Beyer
Eric C
EC
D000256:Adenoviridae / Q000378:metabolism; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects*; D053181:Caspase 8 / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D018031:Connexin 43 / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D016650:Fluorescein-5-isothiocyanate; D019084:Fluorescent Antibody Technique, Indirect; D005456:Fluorescent Dyes; D006801:Humans; D007700:Kinetics; D008297:Male; D011419:Propidium; D011471:Prostatic Neoplasms / Q000473:pathology; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology
D017304:Annexin A5; D018031:Connexin 43; D005456:Fluorescent Dyes; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D011419:Propidium; D053181:Caspase 8; D016650:Fluorescein-5-isothiocyanate