High expression of GADD-45α and VEGF induced tumor recurrence via upregulation of IL-2 after photodynamic therapy using NPe6

Abstract

Abstract. NPe6 is a novel second-generation photosensitizer used for photodynamic therapy (PDT). PDT using NPe6 and diode laser (664 nm) induces cell death, inflammatory reactions, immunological responses and damage to the microvasculature. In this study, we evaluated the influence of the immunological responses and of enhanced angiogenesis on the anti-tumor effect of NPe6-PDT using cytokine-overexpressing Lewis lung carcinoma (LLC), LLC-IL-2 cells both in vitro and in vivo. We showed by DNA microarray analysis in vitro that IL-2 and GADD-45α (growth arrest and DNA damage 45 alpha) mRNA expressions were induced by 3 h after NPe6-PDT applied at a dose killing 90% of the cells (LD 90 ). IL-2-overexpressing cells (LLC/IL-2 cells) were resistant to the loss of clonogenicity as compared to the parental LLC cells in vitro. Furthermore, in female C57BL/6 mice, NPe6-PDT produced a cure rate of 66.7% in LLC tumors, whereas the cure rate was only 16.6% in LLC/IL-2 tumors, and overexpression of IL-2 caused failure of NPe6-PDT, with tumor recurrence, in vivo. These results suggest that IL-2 expression may play an unfavorable role in attenuation of the antitumor effect of NPe6-PDT. It has been reported that the expression of vascular endothelial growth factor (VEGF), in particular, may cause tumor recurrence after PDT and exert unfavorable effect in relation to attenuate the anti-tumor activity of PDT. Results of immunohistochemical analysis of LLC/IL-2 tumors have revealed that the expressions of GADD-45α and VEGF are induced in these tumors after PDT, and in particular, 12 h after PDT, the expression levels were much higher as compared with those in the LLC tumors. The results of our studies using in vitro and in vivo models suggest that the cell death caused by PDT was inhibited by induction of GADD-45α expression and that tumor recurrence was promoted by the enhancement of VEGF expression mediated by IL-2 upregulation. Therefore, it is speculated that the use of an IL-2 inhibitor may improve the efficacy of NPe6-PDT.

Combination effect of photodynamic therapy using NPe6 with pemetrexed for human malignant pleural mesothelioma cells

“…After rinsing twice with PBS, the fixed cells were incubated in ifa buffer (PBS containing 1% bovine serum albumin, 0.1% tween-20) for 10 min and then in ifa-containing mouse anti-tS antibody (clone 8f1; zymed laboratories, inc., San francisco, ca, uSa) for 1 h at room temperature (26,30,32).…”

“…treatments were initiated 7 days after tumor cell implantation, when the MSto-211H tumors were ~200 mm 3 in volume. the tumor volumes were calculated using the following formula: tumor volume = lD 2 /2 (l, long diameter; D, short diameter) (32). for the pemetrexed followed by PDt treatment, mice were intraperitoneally injected with pemetrexed (150 mg/kg daily) on days 7-11; on day 12, the mice were intravenously injected with nPe6 (10 mg/kg) and irradiated with a 664-nm laser (100 j/cm 2 ) 2 h later.…”

A 205-Nucleotide Deletion in the 3′ Untranslated Region of Avian Leukosis Virus Subgroup J, Currently Emergent in China, Contributes to Its Pathogenicity

“…Furthermore, VEGF-A, a potent inducer of angiogenesis, and VEGFR-2 both play crucial roles in angiogenesis (67). Much research has shown that high levels of VEGF-A and VEGFR-2 induce tumor formation through specific signaling pathways (8,42). To explore the possible molecular mechanism underlying the increased oncogenicity of rHLJ09SH01, ED 3.5 chick embryos were inoculated with rHLJ09SH01 and rHLJ09SH01A205 through the yolk sac (where erythropoiesis in the chicken embryo begins) (70).…”

Outcome of Photodynamic Therapy Using NPe6 for Bronchogenic Carcinomas in Central Airways >1.0 cm in Diameter

“…A phase II clinical study of NPe6 and a diode laser for the treatment of CLELCs showed an excellent antitumor effect and safety, including significantly lower skin photosensitivity than with Photofrin-PDT (7). Because (630 nm) the mechanism of action of NPe6-PDT differs from that of Photofrin-PDT, because the absorption band of NPe6 is longer than that of Photofrin (5,(8)(9)(10), we hypothesized that NPe6-PDT would have a stronger antitumor effect on deeper lesions than Photofrin-PDT does.…”