Inhibition of renalase drives tumour rejection by promoting T cell activation.

BACKGROUND: Although programmed cell death protein 1 (PD-1) inhibitors have revolutionised treatment for advanced melanoma, not all patients respond. We previously showed that inhibition of the flavoprotein renalase (RNLS) in preclinical melanoma models decreases tumour growth. We hypothesised that RNLS inhibition promotes tumour rejection by effects on the tumour microenvironment (TME). METHODS: We used two distinct murine melanoma models, studied in RNLS knockout (KO) or wild-type (WT) mice. WT mice were treated with the anti-RNLS antibody, m28, with or without anti-PD-1. 10X single-cell RNA-sequencing was used to identify transcriptional differences between treatment groups, and tumour cell content was interrogated by flow cytometry. Samples from patients treated with immunotherapy were examined for RNLS expression by quantitative immunofluorescence. RESULTS: RNLS KO mice injected with wild-type melanoma cells reject their tumours, supporting the importance of RNLS in cells in the TME. This effect was blunted by anti-cluster of differentiation 3. However, MØ-specific RNLS ablation was insufficient to abrogate tumour formation. Anti-RNLS antibody treatment of melanoma-bearing mice resulted in enhanced T cell infiltration and activation and resulted in immune memory on rechallenging mice with injection of melanoma cells. At the single-cell level, treatment with anti-RNLS antibodies resulted in increased tumour density of MØ, neutrophils and lymphocytes and increased expression of IFNγ and granzyme B in natural killer cells and T cells. Intratumoural Forkhead Box P3 + CD4 cells were decreased. In two distinct murine melanoma models, we showed that melanoma-bearing mice treated with anti-RNLS antibodies plus anti-PD-1 had superior tumour shrinkage and survival than with either treatment alone. Importantly, in pretreatment samples from patients treated with PD-1 inhibitors, high RNLS expression was associated with decreased survival (log-rank P = 0.006), independent of other prognostic variables. CONCLUSIONS: RNLS KO results in melanoma tumour regression in a T-cell-dependent fashion. Anti-RNLS antibodies enhance anti-PD-1 activity in two distinct aggressive murine melanoma models resistant to PD-1 inhibitors, supporting the development of anti-RNLS antibodies with PD-1 inhibitors as a novel approach for melanomas poorly responsive to anti-PD-1.

Extracellular renalase protects cells and organs by outside-in signalling.

Renalase was discovered as a protein synthesized by the kidney and secreted in blood where it circulates at a concentration of approximately 3-5 µg/ml. Initial reports suggested that it functioned as an NAD(P)H oxidase and could oxidize catecholamines. Administration of renalase lowers blood pressure and heart rate and also protects cells and organs against ischaemic and toxic injury. Although renalase's protective effect was initially ascribed to its oxidase properties, a paradigm shift in our understanding of the cellular actions of renalase is underway. We now understand that, independent of its enzymatic properties, renalase functions as a cytokine that provides protection to cells, tissues and organs by interacting with its receptor to activate protein kinase B, JAK/STAT, and the mitogen-activated protein kinase pathways. In addition, recent studies suggest that dysregulated renalase signalling may promote survival of several tumour cells due to its capacity to augment expression of growth-related genes. In this review, we focus on the cytoprotective actions of renalase and its capacity to sustain cancer cell growth and also the translational opportunities these findings represent for the development of novel therapeutic strategies for organ injury and cancer.

Renalase Expression by Melanoma and Tumor-Associated Macrophages Promotes Tumor Growth through a STAT3-Mediated Mechanism.

To sustain their proliferation, cancer cells overcome negative-acting signals that restrain their growth and promote senescence and cell death. Renalase (RNLS) is a secreted flavoprotein that functions as a survival factor after ischemic and toxic injury, signaling through the plasma calcium channel PMCA4b to activate the PI3K/AKT and MAPK pathways. We show that RNLS expression is increased markedly in primary melanomas and CD163(+) tumor-associated macrophages (TAM). In clinical specimens, RNLS expression in the tumor correlated inversely with disease-specific survival, suggesting a pathogenic role for RNLS. Attenuation of RNLS by RNAi, blocking antibodies, or an RNLS-derived inhibitory peptide decreased melanoma cell survival, and anti-RNLS therapy blocked tumor growth in vivo in murine xenograft assays. Mechanistic investigations showed that increased apoptosis in tumor cells was temporally related to p38 MAPK-mediated Bax activation and that increased cell growth arrest was associated with elevated expression of the cell-cycle inhibitor p21. Overall, our results established a role for the secreted flavoprotein RNLS in promoting melanoma cell growth and CD163(+) TAM in the tumor microenvironment, with potential therapeutic implications for the management of melanoma. Cancer Res; 76(13); 3884-94. ©2016 AACR.

Inhibition of renalase expression and signaling has antitumor activity in pancreatic cancer.

An essential feature of cancer is dysregulation of cell senescence and death. Renalase, a recently discovered secreted flavoprotein, provides cytoprotection against ischemic and toxic cellular injury by signaling through the PI3K-AKT and MAPK pathways. Here we show that renalase expression is increased in pancreatic cancer tissue and that it functions as a growth factor. In a cohort of patients with pancreatic ductal adenocarcinoma, overall survival was inversely correlated with renalase expression in the tumor mass, suggesting a pathogenic role for renalase. Inhibition of renalase signaling using siRNA or inhibitory anti-renalase antibodies decreased the viability of cultured pancreatic ductal adenocarcinoma cells. In two xenograft mouse models, either the renalase monoclonal antibody m28-RNLS or shRNA knockdown of renalase inhibited pancreatic ductal adenocarcinoma growth. Inhibition of renalase caused tumor cell apoptosis and cell cycle arrest. These results reveal a previously unrecognized role for the renalase in cancer: its expression may serve as a prognostic maker and its inhibition may provide an attractive therapeutic target in pancreatic cancer.

The Rise and Fall of Accelerated Partial Breast Irradiation via Brachytherapy in a Single Institution.

UNLABELLED: Accelerated partial breast irradiation via brachytherapy (APBI-b) is offered as an alternative to whole breast irradiation (WBI) for selected patients with breast cancer. This study evaluates our clinical experience with APBI-b to identify the reasons for decreased clinical utilization in recent years. We performed an analysis of the prospective database of breast cancer patients treated with APBI-b between 2004 and 2013. During that time, 245 patients received APBI-b, most having stage I (77%) or stage 0 (20%) breast cancer. Since 2004, the number of APBI-b cases per year rose to 49 in 2009, declining thereafter to 14 in 2013 (P < 0.001). The APBI-b case volume dropped in 2010 following the publication of the American Society of Radiation Oncology (ASTRO) consensus guidelines in 2009. After 2009 fewer unsuitable cases received APBI-b (11% vs. 4%,P = 0.1). CONCLUSION: The clinical utilization of APBI-b has decreased after the publication of consensus guidelines. A reduction in unsuitable cases treated after 2009 does not explain the global loss of referrals.

The novel tumor angiogenic factor, adrenomedullin-2, predicts survival in pancreatic adenocarcinoma.

BACKGROUND: Tumor angiogenesis has been demonstrated to have an important role in the development, progression, and metastasis of pancreas cancer. Adrenomedullin-2 (ADM2) is a calcitonin gene-related peptide that has recently been shown to be a novel tumor angiogenesis factor, acting via mitogen-activated protein kinase/extracellular signal-regulated kinase, phosphoinositide 3-kinase/Akt, and vascular endothelial growth factor/vascular endothelial growth factor-2 signaling pathways. Through the use of tissue microarray (TMA) technology, we hypothesize that ADM2 is an important tumor angiogenesis factor in pancreatic cancer. METHODS: Multiple TMAs were created using tissue from pancreatic cancer patients resected between January 1996 and December 2006. Core tissue samples of formalin-fixed, paraffin-embedded blocks of pancreatic cancer tissue were collected through an institutional review board-approved protocol and linked to available clinicopathologic data. Two TMAs consisting of 112 and 60 patients with pancreatic adenocarcinoma were studied for ADM2 protein expression using a quantitative, automated immunofluorescent microscopy system, a technology that removes potential observer bias in TMA analysis. The results were analyzed using independent Student t-test, chi-square, log-rank regression, and Kaplan-Meier methods. RESULTS: One hundred sixteen patients were identified for complete analysis, and 56 patients had complete survival data. Median follow-up for survivors was 14.5 mo. Total cellular levels of ADM2 were found to be a predictor of survival in pancreatic cancer. Low ADM2 levels were associated with a higher 5-y survival compared with high ADM2 levels (18% versus 6%, P = 0.05). Median survival was also worse in high ADM2 expressers (18.7 versus 8.6 mo). In accordance with prior-published pancreatic cancer data, a worse histologic grade (P = 0.001), tumor (T) stage (P = 0.009), and overall disease stage (P = 0.004), all portended a worse survival. CONCLUSIONS: For the first time, we have demonstrated that high levels of ADM2 expression predict a poorer survival in patients with pancreatic adenocarcinoma. This suggests a possible role of ADM2 in pancreas cancer and as a novel biomarker that predicts poorer survival. Additional study of ADM2 in pancreatic cancer will help reveal its true angiogenic role in pancreas cancer and its potential role as a novel therapeutic target.

Infected urachal cyst secondary to a Crohn's enterourachal fistula.

Enterourachal fistulas are exceedingly rare in Crohn's patients. We report a case of a presumed enterourachal fistula that led to an infected urachal cyst. Preoperative medical treatment obliterated the fistula and avoided the need to resect bowel at the time of operation. We recommend consideration of this diagnosis in a Crohn's patient with a midline abdominal mass.

Predictive value of response to steroid therapy on response to splenectomy in children with immune thrombocytopenic purpura.

BACKGROUND: Many but not all studies suggest that a favorable response to preoperative steroid therapy predicts a successful outcome after splenectomy in children with immune thrombocytopenic purpura (ITP). The purpose of this study is to further examine the relationship between steroid response and outcome after splenectomy in children. METHODS: After institutional review board approval, records of children undergoing splenectomy for ITP were reviewed. Patients' responses were determined by platelet counts and grouped by complete response (CR; ≥ 150,000/µL), partial response (PR; 149,999- ≥ 50,000/µL), or no response (NR; <50,000/µL). RESULTS: Thirty-seven children were identified. After steroid therapy, 20 patients (54%) had CR, 9 (24%) had PR, and 8 (22%) had NR. After splenectomy, 31 patients (84%) had CR, 6 (16%) had PR, and 0 had NR. Of the 20 patients that had a CR to steroid therapy, 18 (80%) had CR and 2 (20%) had PR to splenectomy. Of the 9 patients that had PR to steroids, 7 (78%) had CR to splenectomy and 2 (22%) had PR. Of the 8 patients that had NR to steroids, 6 (75%) had CR and 2 (25%) had PR to splenectomy. Response to splenectomy was not associated with response to steroids (P = .59). CONCLUSION: These data suggest that response to splenectomy in children with ITP is unrelated to previous response to steroids.