Activation of complement C3, C5, and C9 genes in tumors treated by photodynamic therapy

Abstract

Cancer therapies, which deliver a rapidly induced massive tumor tissue injury, such as photodynamic therapy (PDT), provoke a strong host response raised for dealing with the inflicted local trauma. Activated complement system was identified as an important element of host response elicited by tumor PDT. The expression of genes encoding complement proteins C3, C5, and C9 was studied following tumor PDT mediated by photosensitizer Photofrin using mouse Lewis lung carcinoma (LLC) model. Treated tumors and the livers of host mice were collected at different times after PDT and the expression of the investigated genes was analyzed by RT-PCR. The results show a significant up-regulation of C3, C5, and C9 genes in PDT-treated tumors at 24 h after therapy, while no significant increase in the expression of these genes was found in the liver tissues. The expression of C3, C5, and C9 genes also became up-regulated in untreated tumor-associated macrophages (TAMs) co-incubated in vitro with PDT-treated LLC cells. This effect was abolished or drastically reduced in the presence of antibodies blocking heat shock protein 70 (HSP70), Toll-like receptor (TLR) 2 and TLR4, and specific peptide inhibitors of TIRAP adapter protein and transcription factor NF-kappaB. The presented study reveals that complement genes C3, C5, and C9 become up-regulated in tumors treated by PDT, but not in the host's liver. Tumor-localized up-regulation of these genes can be largely attributed to monocytes/macrophages invading the treated lesion after PDT. This effect appears to be induced by the recognition of danger signals from PDT-treated tumor cells such as HSP70 by TAMs that involve the TLR2- and TLR4-triggered signal transduction pathways leading to the activation of NF-kappaB.

New Two-Photon Activated Photodynamic Therapy Sensitizers Induce Xenograft Tumor Regressions after Near-IR Laser Treatment through the Body of the Host Mouse

“…The lack of neutrophil infiltration in A549 tumors that were not regressing at the time of sacrifice is interesting and suggests that there is a limiting factor acting on the granulocyte lineage. This could well be due to insufficient tumor damage occurring to stimulate up-regulation of complement genes, particularly C3a, thought to be major mediators of the post-PDT neutrophil response (5). A lesser PDT response would be expected for the A549 cell line that does not express SST2r and so should not internalize the sensitizer.…”

“…The triplet excitation energy can be effectively transferred to molecular oxygen, resulting in the generation of singlet oxygen, superoxide radical, and other active oxygen species (2,3). The singlet oxygen causes direct chemical damage to tumor and/or tumor endothelial cells (4), initiates a neutrophilic inflammatory response (5), and can stimulate both innate and specific antitumor immune responses (6 -8). Singlet-oxygen production, however, requires a sufficiently high energy of the triplet state of the sensitizer.…”

Molecular cloning and expression analysis of Pleurodeles waltl complement component C3 under normal physiological conditions and environmental stresses

“…Another possibility is that danger signals, such as HSP, that are induced by heat shock (Fig. 2E) up-regulate C3 expression, as shown in photodynamic therapy-treated tumors (Stott and Korbelik, 2007). An inspection of know C3 promoter sequences (human, mouse and rat) using the Match and TFSEARCH programs (available at http://www.gene-regulation.com/cgi-bin/pub/programs/match/bin/match.cgi and http://www.cbrc.jp/research/db/ TFSEARCH.html) confirmed the presence of heat shock protein binding sites (data not shown).…”

Photodynamic therapy for enhancing antitumour immunity

“…Cecic and Korbelik 38 showed that Photofrin-PDT induces the fixation of complement C3 protein (probably in the form of its activated fragments) and of the terminal complement membrane attack complex on the treated SCCVII cells. Stott and Korbelik 39 assessed expression of C3, C5 and C9 genes in tumours and they showed that The mechanisms of antitumour effects triggered by PDT. In the first case, PDT induces generation of reactive oxygen species (ROS) which directly can kill tumour cells by apoptosis and/or necrosis.…”