Bcl-2 anti-apoptotic oncoprotein suppresses angiogenesis in non-small cell lung cancer: implications in resistance to photodynamic treatment?

PDT cytotoxicity is likely to occur through photooxidative reactions. In that way mechanisms that define poor oxygenation should be involved in defining resistance to photo-dynamic treatment (PDT). On the other hand bcl-2 anti- apoptotic protein has been shown to delay cell death and protect cells from toxic oxidative products. We examined 134 specimens from T1,2-NO,1 staged patients treated with surgery alone. Specimens were immunohistochemically examined for vascular grade using the JC70 MoAb, and bcl-2 oncoprotein expression. Bcl-2 expression correlated with low vascular grade. Only 3/27 of bcl2+ case had high angiogenesis vs. 34/107 of cases without bcl-2 expression. In the present study we provide evidence that bcl-2 overexpression directly suppresses angiogenesis in non-small cell lung cancer, which obviously results in decreased blood supply and oxygenation. This finding implies that reduced intratumoral angiogenesis and immortalizing oncoprotein overexpression are linked to each other and may have a role in defining tumors resistant to PDT.