Study On Treatment Of Transplanted Pancreatic Cancer By Gemcitabine Combined With Photodynamic Therapy

BACKGROUND: Photodynamic therapy (PDT) is a new treatmentwhich is developed in the1980s. Currently, there is few researches on thePDT treatment of pancreatic cancer in vivo. In addition, RGD peptide,existing in organisms widely, mediates the adhesion of cells andextracellular matrix and cells through its RGD sequence-specific binding tothe cell surface integrins (αvβ3) receptor. Gemcitabine is the priory treatmentfor advanced pancreatic cancer. Additionally, the chemotherapy not onlyhas the ability of anti-cancer effects but also can affects DNA synthesisand repair in tumor cells. Some studies showed that PDT can not onlyinduce apoptosis in pancreatic cancer cells but also reduce first-linechemotherapy drug gemcitabine resistance in pancreatic cancer in vitro.OBJECTIVE: To investigate the effects of gemcitabine combinedwith photodynamic therapy (PDT) in treatment of human pancreatic cancerxenograft in nude mice. METHODS:(1) Preparation probe of Quantum dots-RGD.(2)Quantum dots-RGD probe targeting research on pancreatic cancer cells invivo and vitro.(3) The animal model of human pancreatic cancer wasdeveloped by suturing small pieces of tumors into the dorsum of nude mice.They were randomly divided into five groups, which were control group(without any treatment), simple illumination group （630nm，120J/cm2，20min of duration）, PDT group（RGD-QDs0.5nmol combined with laserirradiation）, gemcitabine group（50mg/kg of gemcitabine）and gemcitabinecombined with PDT group(0.5nmol of QDs-RGD combined with laserirradiation and50mg/kg of gemcitabine). All the nudes were killed after18days. The tumor volume, weight and inhibitory effect were calculated.RESULTS:(1) Quantum dots-RGD was successfully synthesized.(2)Quantum dots-RGD probe demonstrated the enhanced tumor-selectivity topancreatic cancer cells.(3) The tumor weight of PDT group, gemcitabinegroup and combination group were （1.75±0.48）g,（1.57±0.37）g and（0.82±0.26）g respectively. The weight of combination was lighter thanPDT group and gemcitabine group (all P value<0.05). The weight of abovegroups were lighter than control group significantly (P value<0.001). CONCLUSIONS: Gemcitabine combined with PDT therapy couldinhibit the growth of tumors in nudes, which meant that it had significantanti-tumor effect.