TUMOR CELL-ENHANCED SENSITIVITY OF VASCULAR ENDOTHELIAL-CELLS TO PHOTODYNAMIC THERAPY

Effective antitumor photodynamic therapy (PDT) may be related to damag e of vasculature within the tumor, The purpose of this study was to de termine if tumor cells secrete factors that stimulate proliferation of human umbilical vein endothelial cells (HUVEG) and result in enhanced sensitivity of HUVEC to aluminum-sulfonated phthalocyanine (AlSPc)-PD T. Three human tumor cell lines-pharyngeal squamous carcinoma, colonic carcinoma, and mammary carcinoma-were used in this study. Co-culture of HUVEG and either squamous carcinoma or colonic carcinoma, but not m ammary carcinoma, significantly increased HUVEC proliferation and AlSP c-PDT mediated cell damage. In addition, supernatant from squamous car cinoma and colonic carcinoma cultures also stimulated HUVEC proliferat ion and sensitivity to AlSPc-PDT. Both supernatant and cell lysate fro m squamous carcinoma cells contained angiogenic factors consistent wit h basic and acidic fibroblast growth factors, as evidenced by Western blot analysis and BALB/c 3T3 fibroblast cell proliferation assays, Col lectively, these results suggest that selected tumor cell lines produc e angiogenic factors that induce HUVEC proliferation and subsequently enhance sensitivity to AlSPc-PDT, (C) 1994 Wiley-Liss, Inc.