phytochlorin and Cell-Transformation--Neoplastic

Paclitaxel (PTX) can bind to human serum albumin (HSA) via hydrophobic interaction, forming Abraxane, which is a U.S. Food and Drug Administration (FDA) approved effective antitumor nanomedicine drug. Herein, the effective antitumor drug PTX is used to induce the self-assembly of HSA modified with either a photosensitizer chlorin e6 (Ce6), which at the same time serves as a chelating agent for Mn(2+) to enable magnetic resonance imaging, or acyclic Arg-Gly-Asp (cRGDyK) peptide that targets αvβ3-integrin overexpressed on tumor angiogenic endothelium. Two types of tumor-targeting theranostic nanoparticles are constructed, either by coassembly of both HSA-Ce6 and HSA-RGD simultaneously or by forming an HSA-Ce6@HSA-RGD core-shell structure, with the assistance of PTX-induced albumin aggregation. Such albumin-based nanoparticles on one hand could targetαvβ3-integrin, as evidenced by both in vitro and in vivo experiments, and on the other hand enable combined photodynamic/chemotherapy, which offers remarkably improved therapeutic efficacy to kill cancer in comparison to the respective monotherapies. Our work presents a new type of tumor-targeted multifunctional albumin-based nanoparticles by drug-induced self-assembly, which is a rather simple method without any sophisticated chemistry or materials engineering and is promising for multimodel imaging-guided combination therapy of cancer.

Topics: Animals; Cell Line, Tumor; Cell Transformation, Neoplastic; Chlorophyllides; Combined Modality Therapy; Female; Glioblastoma; Humans; Hydrophobic and Hydrophilic Interactions; Mice; Models, Molecular; Molecular Targeted Therapy; Oligopeptides; Paclitaxel; Porphyrins; Protein Aggregates; Protein Conformation; Serum Albumin; Theranostic Nanomedicine

Photodynamic therapy (PDT) is currently being used as an alternative therapeutic modality for a variety of malignant tumors. This study was performed to show an efficient preparation of second generation of photosensitizer chlorin e6 (Ce6) with high yield and purity, and to test antitumor activity of Ce6-induced PDT (Ce6-PDT) both in vitro and in vivo using a rat tumor model. Three-week-old male Sprague-Dawley (SD) rats were inoculated s.c. on the right flank with 5x10(6) RK3E-ras cells. The animals were administered i.v. with Ce6 (10 mg/kg) and 24 h later, PDT was performed using a laser diode at a light dose of 100 J/cm2. Ce6-PDT generated reactive oxygen species and led to significant growth inhibition in RK3E-ras cell. In addition, Ce6-PDT induced apoptosis through the activation of caspase-3 and its downstream target, PARP cleavage. The protein level of anti-apoptotic bcl-2 was also reduced by Ce6-PDT in RK3E-ras cells. In in vivo experiments, application of Ce6-PDT led to a significant reduction of tumor size. PCNA immunostaining and TUNEL assay revealed that Ce6-PDT inhibited tumor cell proliferation and increased apoptosis. These findings suggest that the newly purified Ce6-PDT can effectively arrest tumor growth by inhibiting cell proliferation and inducing apoptosis.

Topics: Animals; Apoptosis; Blotting, Western; Caspase 3; Cell Proliferation; Cell Transformation, Neoplastic; Chlorophyllides; Flow Cytometry; Immunoenzyme Techniques; Kidney; Lasers; Male; Neoplasms, Experimental; Photochemotherapy; Poly(ADP-ribose) Polymerases; Porphyrins; Radiation-Sensitizing Agents; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Xenograft Model Antitumor Assays