Deregulated hyaluronan metabolism in the tumor microenvironment drives cancer inflammation and tumor-associated immune suppression.

Hyaluronan (HA) is known to be a prominent component of the extracellular matrix in tumors, and many solid cancers are characterized by aberrant HA metabolism resulting in increased production in tumor tissue. HA has been implicated in regulating a variety of cellular functions in tumor cells and tumor-associated stromal cells, suggesting that altered HA metabolism can influence tumor growth and malignancy at multiple levels. Importantly, increased HA production in cancer is associated with enhanced HA degradation due to high levels of expression and activity of hyaluronidases (Hyal).

Acute Kidney Injury-Induced Systemic Inflammation and Risk of Kidney Cancer Formation.

In this issue of , Zhou and colleagues investigate the role of acute kidney injury (AKI) and AKI-associated systemic inflammation in the development of kidney cancer. They demonstrate a positive association between the formation of clear-cell renal cell carcinoma and AKI induced by ischemia-reperfusion injury in genetically modified mice. In parallel with the emergence of kidney tumors, mice with ischemic injury develop systemic inflammation associated with tissue infiltration by neutrophils and fibroblasts and upregulated expression of several inflammatory factors, with CXCL1 displaying the highest levels of upregulation.

Hyal2 Expression in Tumor-Associated Myeloid Cells Mediates Cancer-Related Inflammation in Bladder Cancer.

The increased presence of myeloid-derived suppressor cells (MDSC) and tumor-associated macrophages (TAM) in tumor tissue has been extensively reported. However, their role in the regulation of hyaluronan (HA) metabolism in the tumor microenvironment has not been established. Here we describe a novel function of tumor-associated myeloid cells related to the enhanced breakdown of extracellular HA in human bladder cancer tissue, leading to the accumulation of small HA fragments with molecular weight (MW) <20 kDa.

Mechanisms of immune evasion in bladder cancer.

With the introduction of multiple new agents, the role of immunotherapy is rapidly expanding across all malignancies. Bladder cancer is known to be immunogenic and is responsive to immunotherapy including intravesical BCG and immune checkpoint inhibitors. Multiple trials have addressed the role of checkpoint inhibitors in advanced bladder cancer, including atezolizumab, avelumab, durvalumab, nivolumab and pembrolizumab (all targeting the PD1/PD-L1 pathway).

Calcium Oxalate Differentiates Human Monocytes Into Inflammatory M1 Macrophages.

Purpose: A number of hyperoxaluric states have been associated with calcium oxalate (CaOx) deposits in the kidneys. In animal models of stone disease, these crystals interact with circulating monocytes that have migrated into the kidney as part of innate immunity. Similarly, macrophages surround CaOx crystals in kidneys of patients excreting high levels of oxalate.

COX2/mPGES1/PGE2 pathway regulates PD-L1 expression in tumor-associated macrophages and myeloid-derived suppressor cells.

In recent years, it has been established that programmed cell death protein ligand 1 (PD-L1)-mediated inhibition of activated PD-1 T lymphocytes plays a major role in tumor escape from immune system during cancer progression. Lately, the anti-PD-L1 and -PD-1 immune therapies have become an important tool for treatment of advanced human cancers, including bladder cancer. However, the underlying mechanisms of PD-L1 expression in cancer are not fully understood.

Calcium Oxalate Stone Fragment and Crystal Phagocytosis by Human Macrophages.

Purpose: In murine and human hyperoxaluric conditions macrophages can be seen surrounding renal calcium oxalate crystal deposits. We hypothesized that macrophages have a role in degrading and destroying these deposits. We investigated the inflammatory response and phagocytic mechanisms when macrophages were exposed to human kidney stones and inorganic crystals.

Expansion of CCR8(+) inflammatory myeloid cells in cancer patients with urothelial and renal carcinomas.

Purpose: Chemokines are involved in cancer-related inflammation and malignant progression. In this study, we evaluated expression of CCR8 and its natural cognate ligand CCL1 in patients with urothelial carcinomas of bladder and renal cell carcinomas.

Experimental Design: We examined CCR8 expression in peripheral blood and tumor tissues from patients with bladder and renal carcinomas.

Enhanced 15-lipoxygenase activity and elevated eicosanoid production in kidney tumor microenvironment contribute to the inflammation and immune suppression.

Macrophage infiltration is a hallmark in the majority of solid tumors. Our studies demonstrated that macrophages that infiltrate human renal cells carcinoma (RCC) display markedly enhanced expression and activity of 15-lipoxygenase-2 (15-LOX2). Obtained data suggest that enhanced lipoxygenase activity in tumor-associated macrophages stimulates cancer inflammation and causes immune dysfunction.

Tumor-associated macrophages mediate immunosuppression in the renal cancer microenvironment by activating the 15-lipoxygenase-2 pathway.

Renal cell carcinoma (RCC), the most common human kidney cancer, is frequently infiltrated with tumor-associated macrophages (TAM) that can promote malignant progression. Here, we show that TAMs isolated from human RCC produce substantial amounts of the proinflammatory chemokine CCL2 and immunosuppressive cytokine IL-10, in addition to enhanced eicosanoid production via an activated 15-lipoxygenase-2 (15-LOX2) pathway. TAMs isolated from RCC tumors had a high 15-LOX2 expression and secreted substantial amounts of 15(S)-hydroxyeicosatetraenoic acid, its major bioactive lipid product.

Circulating and tumor-infiltrating myeloid cell subsets in patients with bladder cancer.

Both cancer-related inflammation and tumor-induced immune suppression are associated with expansion of myeloid cell subsets including myeloid-derived suppressor cells. However, little known regarding characteristics of myeloid cells in patients with bladder cancer. In this study, we analyzed myeloid cells from peripheral blood (PBMC) and tumor tissue that were collected from patients with superficial noninvasive and invasive urothelial carcinomas.

Aberrant PGE₂ metabolism in bladder tumor microenvironment promotes immunosuppressive phenotype of tumor-infiltrating myeloid cells.

Bladder cancer is associated with enhanced inflammation and characterized by deregulated prostanoid metabolism. Here we examined prostaglandin E₂ (PGE₂) metabolism and myeloid cell subsets that infiltrate tumor tissue using two xenograft models of human bladder cancer. Human bladder tumor xenografts implanted into athymic nude mice become highly infiltrated with host CD11b myeloid cells of bone marrow origin.

Pivotal Advance: Tumor-mediated induction of myeloid-derived suppressor cells and M2-polarized macrophages by altering intracellular PGE₂ catabolism in myeloid cells.

Recent studies suggest that tumor-infiltrated myeloid cells frequently up-regulate COX-2 expression and have enhanced PGE₂ metabolism. This may affect the maturation and immune function of tumor-infiltrated antigen-presenting cells. In vitro studies demonstrate that tumor-derived factors can skew GM-CSF-driven differentiation of T(h)1-oriented myeloid APCs into M2-oriented Ly6C(+)F4/80(+) MDSCs or Ly6C(-)F4/80(+) arginase-expressing macrophages.

Identification of ROS using oxidized DCFDA and flow-cytometry.

Cells constantly generate reactive oxygen species (ROS) during aerobic metabolism. The ROS generation plays an important protective and functional role in the immune system. The cell is armed with a powerful antioxidant defense system to combat excessive production of ROS.

Experimental cancer therapy using restoration of NAD+ -linked 15-hydroxyprostaglandin dehydrogenase expression.

Preclinical and clinical evidence shows that cyclooxygenase-2 (Cox-2)-mediated prostaglandin E(2) (PGE(2)) overexpression plays an important role in tumor growth, metastasis, and immunosuppression. It has been shown that expression of NAD(+)-linked 15-hydroxyprostaglandin dehydrogenase (15-PGDH), a key enzyme responsible for PGE(2) inactivation, is suppressed in the majority of cancers, including breast and colon carcinoma. We have developed adenoviral vectors (Ad) encoding the 15-PGDH gene under control of the vascular endothelial growth factor receptor 1 (VEGFR1/flt-1; Adflt-PGDH) and the Cox-2 (Adcox-PGDH) promoters.

Generation of antigen-presenting cells from tumor-infiltrated CD11b myeloid cells with DNA demethylating agent 5-aza-2'-deoxycytidine.

Tumor-recruited CD11b myeloid cells, including myeloid-derived suppressor cells, play a significant role in tumor progression, as these cells are involved in tumor-induced immune suppression and tumor neovasculogenesis. On the other hand, the tumor-infiltrated CD11b myeloid cells could potentially be a source of immunostimulatory antigen-presenting cells (APCs), since most of these cells represent common precursors of both dendritic cells and macrophages. Here, we investigated the possibility of generating mature APCs from tumor-infiltrated CD11b myeloid cells.

Enhancing the efficacy of cancer vaccines in urologic oncology: new directions.

Immunotherapeutic interventions have long been utilized in urologic oncology for the treatment of metastatic renal cell or superficial transitional cell carcinoma. Most recently, the first active specific immunotherapeutic approach, a cancer vaccine, has passed the final phase of human testing and its approval by the FDA is pending. However, evidence suggests that the full protective and therapeutic potential of cancer vaccines has not yet been achieved.

Effects of CXCR4 antagonist CTCE-9908 on prostate tumor growth.

Background: Recent reports have linked the survival-promoting effect of CXCR4 to the up regulation of Bcl-2 protein expression.

Materials And Methods: To further elucidate the relationship between Bcl-2 and CXCR4, tumorigenicity was evaluated in in vitro and in vivo models following treatment with CTCE-9908, a CXCR4 antagonist peptide.

Results: In vitro, CTCE-9908 inhibited cellular proliferation in PC-3-Bcl-2 and PC-3-Neo cell lines Furthermore in our xenograft model, CTCE-9908 delivered via daily intraperitoneal injections resulted in a statistically significant reduction in tumor size compared to control (396 + 205 mm(3) vs.