We engrafted mice with primary B16-OVA or B16-F10 tumors on a single flank. metastases. To exploit the beneficial effects of PTT activity against local tumors and on antitumor immunity whilst avoiding the adverse consequences, we adoptively transferred gp100-specific pmel T cells following PTT. The combination of local control by PTT and systemic antitumor immune reactivity provided by adoptively transferred T cells prevented primary tumor recurrence post-ablation, inhibited tumor growth at distant sites, and abrogated the outgrowth of lung metastases. Hence, the combination of PTT and systemic immunotherapy prevented the adverse effects of PTT on metastatic tumor growth and optimized overall tumor control. Introduction tumor ablative strategies, including radiofrequency ablation and cryoablation, are effective at destroying localized disease and may stimulate the host immune system to recognize and eliminate remaining tumor cells [1]C[4]. Tumor ablation induces necrotic and apoptotic tumor cell Y16 death by direct cytotoxicity and destruction of the tumor microvasculature [5]. Because dying tumor cells provide a source of tumor antigens and induce the expression of natural immune adjuvants, like heat shock proteins [6]C[9] and alarmins [10], they initiate an inflammatory cascade that can promote dendritic cell maturation [11], [12] and culminate in the priming of tumor-specific T cells [13]C[15]. It has been hoped that this immune response would then have secondary beneficial effects on metastatic disease, progression of which is the most common cause of cancer-related deaths. Unfortunately, few local therapies have led to disease eradication by any immune response they putatively induce. We, therefore, Fos examined in greater detail the immune sequelae induced in the wake of local tumor ablation using hyperthermia with the goal of harnessing stimulatory immune components that could be exploited for the eradication of metastatic disease. We characterized the inflammatory and antitumor immune response to B16-F10 melanoma induced by gold nanoshell-enabled photothermal therapy (PTT), an ablation strategy that utilizes optically tuned gold nanoshells that generate heat upon exposure to near infrared radiation [16], [17]. To evaluate the antitumor effects initiated by PTT, we assessed the growth of distant tumor metastases following primary tumor ablation and identified both stimulatory and inhibitory immune components induced by PTT that promote or suppress immune responses. To enhance systemic antitumor effects, we determined if the immunostimulatory environment induced by PTT could be exploited to promote the expansion and function of adoptively Y16 transferred tumor-specific T cells. We found that PTT promoted the expression of proinflammatory cytokines and chemokines and induced the maturation of dendritic cells (DC) within tumor-draining lymph nodes. These effects did indeed lead to the priming of antitumor CD8+ effector T cell responses. Unfortunately, this response also promoted the generation of myeloid-derived suppressor cells and subsequently Y16 enhanced metastatic tumor growth. The effects of PTT were, however, sufficient to promote the expansion and function of adoptively transferred tumor-specific T cells, such that the combination of PTT and adoptive T cell therapy (ATCT), but not either component alone, benefited both local and metastatic disease. These data suggest Y16 that tumor ablation and adoptive immunotherapy can act in a complementary fashion and may be of value for treatment of human cancer. Materials and Methods Mice C57BL/6J, Albino C57BL/6J-Tyr-2J/J, and B6.Cg-Thy1a/Cy Tg(TcraTcrb)8Rest/J [18] mice were purchased from Jackson Laboratories (Bar Harbor, ME) and maintained in a pathogen-free mouse facility at Baylor College of Medicine according to institutional guidelines. This study was carried out in strict accordance with the recommendations of the Guide for the.
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