Immune consequences of anti-angiogenic therapyin renal cell carcinoma

The Most Common VHL Point Mutation R167Q in Hereditary VHL Disease Interferes with Cell Plasticity Regulation

Von Hippel-Lindau disease (VHL) is a rare hereditary syndrome due to mutations of the VHL tumor suppressor gene. Patients harboring the R167Q mutation of the VHL gene have a high risk of developing ccRCCs. We asked whether the R167Q mutation with critical aspects of pseudo-hypoxia interferes with tumor plasticity. For this purpose, we used wild-type VHL (WT-VHL) and VHL-R167Q reconstituted cells. We showed that WT-VHL and VHL-R167Q expression had a similar effect on cell morphology and colony formation. However, cells transfected with VHL-R167Q display an intermediate, HIF2-dependent, epithelial-mesenchymal phenotype. Using RNA sequencing, we showed that this mutation upregulates the expression of genes involved in the hypoxia pathway, indicating that such mutation is conferring an enhanced pseudo-hypoxic state. Importantly, this hypoxic state correlates with the induction of genes belonging to epithelial-mesenchymal transition (EMT) and stemness pathways, as revealed by GSEA TCGA analysis. Moreover, among these deregulated genes, we identified nine genes specifically associated with a poor patient survival in the TCGA KIRC dataset. Together, these observations support the hypothesis that a discrete VHL point mutation interferes with tumor plasticity and may impact cell behavior by exacerbating phenotypic switching. A better understanding of the role of this mutation might guide the search for more effective treatments to combat ccRCCs.

Cancer Stem Cells: Emerging Key Players in Immune Evasion of Cancers

Cancer stem cells (CSCs) are subpopulations of undifferentiated cancer cells within the tumor bulk that are responsible for tumor initiation, recurrence and therapeutic resistance. The enhanced ability of CSCs to give rise to new tumors suggests potential roles of these cells in the evasion of immune surveillance. A growing body of evidence has described the interplay between CSCs and immune cells within the tumor microenvironment (TME). Recent data have shown the pivotal role of some major immune cells in driving the expansion of CSCs, which concurrently elicit evasion of the detection and destruction of various immune cells through a number of distinct mechanisms. Here, we will discuss the role of immune cells in driving the stemness of cancer cells and provide evidence of how CSCs evade immune surveillance by exerting their effects on tumor-associated macrophages (TAMs), dendritic cells (DCs), myeloid-derived suppressor cells (MDSCs), T-regulatory (Treg) cells, natural killer (NK) cells, and tumor-infiltrating lymphocytes (TILs). The knowledge gained from the interaction between CSCs and various immune cells will provide insight into the mechanisms by which tumors evade immune surveillance. In conclusion, CSC-targeted immunotherapy emerges as a novel immunotherapy strategy against cancer by disrupting the interaction between immune cells and CSCs in the TME.

PBRM1 Mutations as a Predictive Biomarker for Immunotherapy in Metastatic Renal Cell Carcinoma: A Systematic Review

INTRODUCTION: Genomic features linked to prediction of response to immunotherapy in metastatic renal cell carcinoma (mRCC) are still lacking. Protein polybromo-1 (PBRM1) mutations have been studied as a potential biomarker of clinical benefit, with conflicting published data so far. MATERIAL AND METHODS: This systematic review was guided by the standards of the PRISMA statement to identify studies involving mRCC, immunotherapy and mutations in PBRM1. The main objective was to assess the relationship between PBRM1 mutations and response to immune checkpoint inhibitors (ICI) in patients with mRCC. RESULTS: After an initial search that identified 422 studies, 8 studies met the eligibility criteria and were selected for the final analysis. Data are included from 2 trials in the first-line treatment setting, and 6 trials in second- or later treatment lines evaluating the relationship between the presence of PBRM1 mutations and clinical benefit (CB) with ICI treatment. Regarding the first-line treatment setting, the analysis of both studies failed to show any CB in patients with PBRM1 mutations treated with ICI. However, for the second- and later treatment lines, the results were mixed. CONCLUSIONS: PBRM1 mutations may be a potential genomic biomarker to predict response to ICI treatment in patients with mRCC, mainly in second- and later treatment lines, but the existence of conflicting data in the literature highlights an important bias in the studies and the need for additional clinical validation in large, prospective trials.

Tumor Hypoxia Regulates Immune Escape/Invasion: Influence on Angiogenesis and Potential Impact of Hypoxic Biomarkers on Cancer Therapies

The environmental and metabolic pressures in the tumor microenvironment (TME) play a key role in molding tumor development by impacting the stromal and immune cell fractions, TME composition and activation. Hypoxia triggers a cascade of events that promote tumor growth, enhance resistance to the anti-tumor immune response and instigate tumor angiogenesis. During growth, the developing angiogenesis is pathological and gives rise to a haphazardly shaped and leaky tumor vasculature with abnormal properties. Accordingly, aberrantly vascularized TME induces immunosuppression and maintains a continuous hypoxic state. Normalizing the tumor vasculature to restore its vascular integrity, should hence enhance tumor perfusion, relieving hypoxia, and reshaping anti-tumor immunity. Emerging vascular normalization strategies have a great potential in achieving a stable normalization, resulting in mature and functional blood vessels that alleviate tumor hypoxia. Biomarkers enabling the detection and monitoring of tumor hypoxia could be highly advantageous in aiding the translation of novel normalization strategies to clinical application, alone, or in combination with other treatment modalities, such as immunotherapy.

Pembrolizumab in Combination with Axitinib as First-Line Treatment for Patients with Renal Cell Carcinoma (RCC): Evidence to Date

Over the last 18 months, 3 immunotherapy combination regimens (ipilimumab + nivolumab, pembrolizumab + axitinib, and axitinib + avelumab) were approved by the US Food and Drug Administration for the first-line treatment of metastatic renal cell carcinoma (mRCC), making selection of the optimal first-line treatment regimen very challenging. As of April 2020, preferred first-line treatment options for mRCC are pembrolizumab + axitinib and ipilimumab + nivolumab, based on the improvement in overall survival and progression-free survival compared to sunitinib, as observed in pivotal phase III clinical trials. Because the combination of 2 drugs is typically more toxic than a monotherapy, careful attention must be given to overlapping toxicities. The pembrolizumab + axitinib combination led to grade ≥3 adverse events in 75.8% of patients (vs 70.6% in the sunitinib group), while grade ≥3 adverse events were less frequent in the nivolumab + ipilimumab group compared to the sunitinib group. Discontinuation rates due to toxicity were 10.7% for pembrolizumab + axitinib (both drugs), 22% for ipilimumab + nivolumab and were comparable with sunitinib in both studies (13.9% and 12%, respectively). The combination of pembrolizumab + axitinib may have immune-modulating functions that may provide clinical benefit without the additional toxicity observed with ipilimumab + nivolumab. In addition, this tyrosine kinase inhibitor + immune checkpoint combination should have faster treatment response in patients with larger disease burden or in more symptomatic patients, which makes this combination an excellent choice for the first-line treatment regimen for mRCC. These combinations have proven to be tolerable, though long-term results are still lacking. As treatment options for mRCC are rapidly expanding, immunotherapy combinations could potentially change the treatment paradigm, with the ultimate goal of prolonging life and eventually curing mRCC.

Inflammation-Related Mechanisms in Chronic Kidney Disease Prediction, Progression, and Outcome

Persistent, low-grade inflammation is now considered a hallmark feature of chronic kidney disease (CKD), being involved in the development of all-cause mortality of these patients. Although substantial improvements have been made in clinical care, CKD remains a major public health burden, affecting 10–15% of the population, and its prevalence is constantly growing. Due to its insidious nature, CKD is rarely diagnosed in early stages, and once developed, its progression is unfortunately irreversible. There are many factors that contribute to the setting of the inflammatory status in CKD, including increased production of proinflammatory cytokines, oxidative stress and acidosis, chronic and recurrent infections, altered metabolism of adipose tissue, and last but not least, gut microbiota dysbiosis, an underestimated source of microinflammation. In this scenario, a huge step forward was made by the increasing progression of omics approaches, specially designed for identification of biomarkers useful for early diagnostic and follow-up. Recent omics advances could provide novel insights in deciphering the disease pathophysiology; thus, identification of circulating biomarker panels using state-of-the-art proteomic technologies could improve CKD early diagnosis, monitoring, and prognostics. This review aims to summarize the recent knowledge regarding the relationship between inflammation and CKD, highlighting the current proteomic approaches, as well as the inflammasomes and gut microbiota dysbiosis involvement in the setting of CKD, culminating with the troubling bidirectional connection between CKD and renal malignancy, raised on the background of an inflammatory condition.