Induced antitumor immunity against DMBA‐4 metastatic mammary tumors in rats using laser immunotherapy

Abstract

Induced antitumor immunity is a highly effective and longterm cure for cancer, particularly for metastatic tumors. Laser immunotherapy was developed to induce such an immunologic response. It involves intratumoral administration of a light-absorbing dye and a specially formulated immunoadjuvant, followed by noninvasive irradiation of a near-infrared laser. Treatment of DMBA-4 metastatic mammary tumors in rats with this approach has resulted in local control of primary tumors and eradication of untreated distant metastases. After laser immunotherapy, rats were resistant to tumor rechallenge and developed immunity, which could be adoptively transferred. To better understand the immunity induced in this tumor model, immunization using freezethaw DMBA-4 cell lysates was performed, followed by tumor challenge 21 days later. Tumor cell lysate immunization delayed the emergence of metastases but did not provide immunity against the tumor challenge. Also performed was surgical resection of primary tumors before the observation of metastatic tumors. Removal of primary tumors was unsuccessful at changing the course of tumor progression. Tumors re-emerged at the primary sites, and metastases developed at multiple remote sites. In contrast, tumor-bearing rats successfully treated by laser immunotherapy experienced tumor regression and eradication and developed strong resistance to repeated challenges by tumor cells of the same type. Our results show that laser immunotherapy could have potential for the treatment of metastatic tumors by inducing tumor-specific, long-lasting immunity.

Effects of Magnetic Infrared Laser on Xylene-induced Acute Inflammation in Mice

“…Previously reported antioxidative effects of MIL 14,15) are considered by us to be one of the major mechanisms of the anti-inflammatory effect of MIL detected in the present study, because NO synthase inhibitors can reverse several classic inflammatory symptoms 16) . In addition, immune stimulation by MIL therapy [17][18][19][20] may also have been involved in the anti-inflammatory activity detected in the present study, because immunomodulatory agents can reduce inflammation 6) .…”

Effects of Magnetic Infrared Laser Irradiation on Formalin-Induced Chronic Paw Inflammation of Mice

“…Therefore, we consider that MIL showed favorable anti-inflammatory effects on chronic inflammations mediated by cytokineTNF-α suppression. However, we should not excluded the p o s s i b i l i t y t h a t t h e p r e v i o u s l y r e p o r t e d a n t i o x i d a t i v e e f f e c t 2 7 , 2 8 ) a n d i m m u n e stimulation [29][30][31][32] of MIL therapy may also have been involved in the anti-inflammatory activity observed in the present study, because NO synthase inhibitors can reverse several classic inflammatory symptoms 33) and immunomodulatory agents can reduce inflammation 34) . Accordingly, based on the current results, we conclude that MIL therapy had a favorable effect, mediated by TNF-α suppression, on reducing the chronic inflammatory response induced in mouse paws by formalin injection.…”

Anti-tumor response induced by immunologically modified carbon nanotubes and laser irradiation using rat mammary tumor model

“…A similar experiment utilizing LaserþICG-GC and DMBA-4 tumor-bearing rats resulted in a 25% survival rate. 18 The current study increased animal survival by taking advantage of the geometrical con¯guration of the SWNTs to allow better delivery and distrubution of the 980 nm laser light. Additionally, this study investigated the anti-tumor e®ects of SWNTs induced when not conjugated to an immunoadjuvant and laser irradiation was adminstered.…”