Anti-Tumor Efficacy of Photodynamic Therapy of Solid Tumors in Laboratory Animals with Guanidine and Biguanidine Derivatives of Chlorine e6.

We evaluated antitumor efficacy of photodynamic therapy of murine Ehrlich carcinoma and rat sarcoma M-1 with new photosensitizers 131-N-(4-aminobutyl)amydo chlorine e6 (1), 132-(5-guanidylbutanamido)-chlorine e6 (2), and 132-(5-biguanidylbutanamido)-chlorine e6 (3). The inhibiting effect of the photodynamic therapy was evaluated by the following parameters: tumor growth inhibition, complete regression of the tumors, and absolute growth rate of the tumor nodes in animals with the continued neoplasia growth. The criterion of cure was the absence of tumors up to 90 days after the therapy. It is shown that the studied photosensitizers have high antitumor activity in the photodynamic therapy of the Ehrlich carcinoma and sarcoma M-1.

Photodynamic Therapy of Melanoma B16 with Chlorin E6 Conjugated with a PSMA-Ligand.

The efficacy of a new photosensitizer of chlorin E6 conjugated with a prostate-specific membrane antigen (PSMA) in photodynamic therapy of murine melanoma B16 was studied in in vivo experiments. The dynamics of photosensitizer accumulation in the tumor and surrounding tissues was evaluated and antitumor efficacy of photodynamic therapy was assessed by parameters of regression and morphological characteristics of experimental transplanted melanoma B16. The inhibitory effect of photodynamic therapy on melanoma was evaluated by complete regression of the tumor, absolute tumor growth coefficient in animals with continuation of tumor growth, and the increase in life span in comparison with the control; the criterion of cure was the absence of signs of tumor recurrence in mice within 90 days after therapy. The therapeutic potential of photodynamic therapy was determined by devitalization of tumor cells (histological examination of the zones of laser exposure on day 21 after treatment). The photosensitizer with PSMA-ligand exhibited high antitumor activity in photodynamic therapy for melanoma B16. Photodynamic therapy carried out at the optimum time after photosensitizer injection with experimentally determined parameters of laser exposure allows achieving the maximum inhibitory effect on melanoma. Pathomorphological study in the zones of exposure detected no survived tumor cells.