Macrophages are the key effector cells of innate immunity which show two polarized states: M1, classically activated and M2, alternatively activated. Tumor-associated macrophages (TAMs) which usually show M2 polarization, are immunosuppressive cells that enhance tumor metastasis and invasion. Also, enrichment of TAMs is known to be closely associated with poor prognosis of cancer patients. Therefore, TAMs are considered to be promising targets for immunotherapy. Importantly, tumor-derived exosomes emerged as a crucial player in immune regulation which can remodel the tumor microenvironment towards immunosuppressive state. Of note, few studies have shown that exosomes could induce polarization of macrophages towards M2 type in tumor condition, while others showed activation of M1 or mixed phenotype. Considering the role of TAMs in cancer, there is an urgent need to decipher the exosome-mediated cross-talk between tumor cells and macrophages.For this, we used murine model of Dalton’s lymphoma (DL), wherein, firstly, we evaluated increased exosome burden by assessing exosome level in serum as well as in various tissues of tumor-bearing host. Next, proteomic profiling of lymphoma-derived exosomes was done which revealed the presence of immunomodulatory proteins. Of note, these proteins were known to alter the macrophage polarization. In order to assess the effect of these exosomes on macrophages, we performed in vitro study using RAW264.7 cells. In vitro study revealed that frequent uptake of exosomes mediated a morphological change in macrophages which reduced their phagocytic activity. In parallel, exosomes increased reactive oxygen species (ROS) level and inhibited LPS-induced nitric oxide (NO) level in macrophages. Also, exosomes upregulated the expression of arginase-1 (an M2 marker) in macrophages but decreased the LPS-induced nitric oxide synthase 2 (NOS2) (an M1 marker) expression. Moreover, we observed a pro-tumoral cytokine profile in macrophages incubated with exosomes. Our study suggests that exosome load increases in lymphoma-bearing hosts systemically. Importantly, lymphoma-derived exosomes mediate the activation of macrophages towards pro-tumoral M2 type. Our results give an insight into the exosome-mediated tumor and immune cell cross-talk which could serve as an important prospect for targeting in cancer immunotherapy.

Cancer has emerged as a systemic disease which targets various organs thus challenging the overall physiology of the host. Recently, we have shown that hyperactive neutrophils infiltrate various organs of tumor bearing host and contribute significantly to gradual systemic deterioration. Therefore, taming neutrophils via potent immunomodulators could be an appropriate therapeutic approach in regulating systemic damage. Tinospora cordifolia (TC), an Ayurvedic panacea, is known for its immense medicinal values in traditional literature and recent reports have also documented its strong immunomodulatory potential. However, whether TC can regulate neutrophils to exert its therapeutic effectiveness has not been deciphered so far. To discern this, we utilized murine model of Dalton’s Lymphoma (DL) wherein, we have earlier reported heightened infiltration of neutrophils and their hyperactivation. Our findings showed that TC treatment significantly reduced neutrophil count in peripheral blood and their infiltration in vital organs of tumor bearing host. Further, it ameliorated neutrophil hyperactivation by down regulating the expression of its key cargoes including neutrophil elastase (NE), myeloperoxidase (MPO), MMP-8, MMP-9 and cathepsin G (CSTG) at early and mid stage of tumor growth. In addition, TC treatment prevented histopathological alterations and restored the normal serum enzyme levels at different stages of tumor growth. Importantly, TC treatment also showed significant reduction in tumor burden which was accompanied by a remarkable increase in survival of the tumor-bearing mice. We conclude that Tinospora cordifolia could limit systemic damage via regulating neutrophil infiltration and hyperactivation which can further lead to cancer control at both prophylactic and therapeutic level.

Various studies have addressed the role of neutrophils in cancer wherein the focus has been drawn on the elevated neutrophil count in blood or at tumor loci. However, cancer has a systemic impact which targets various organs thus challenging the overall physiology of the host. So, it is worthwhile to explore whether and how neutrophils contribute to systemic deterioration in cancer. To discern the systemic role of neutrophils, we monitored their number and function at different stages of tumor growth in Dalton’s lymphoma mice model. Notably, we observed a gradual increase in neutrophil count in blood and their infiltration in vital organs of tumor bearing mice. In parallel, we observed damaged histoarchitecture with significant alterations in biochemical parameters that aggravated with tumor progression. We next examined systemic impact of neutrophil by assessing neutrophil elastase, myeloperoxidase, and matrix metalloproteinases (MMP-8 and MMP-9) wherein we found their upregulated expression and activity in tumor condition. Taken together, our results demonstrate high infiltration and hyperactivation of neutrophils which possibly account for gradual systemic deterioration during cancer progression. Our findings thus implicate neutrophils as a potential therapeutic target that may help to reduce the overall fatality rate of cancer.