Angiogenesis and angiogenic inhibitors in renal cell carcinoma

Pazopanib-induced trismus in a young male with metastatic renal cell carcinoma: a case report and literature review

The treatment landscape of advanced kidney cancer has radically changed over the years. Targeting tumor angiogenesis from historical cytokines to multi-tyrosine kinase inhibitors and recently the advent of immunotherapy resulted in a radical improvement in survival but presented substantial challenges in terms of toxicity management. In countries where the access to immune checkpoints inhibitors is still very limited, tyrosine-kinase inhibitors remain the optimal choice. The toxicity profile of these agents can influence both the clinician and the patient's preference for one molecule over another. This report describes the case of a young man treated with Pazopanib in a first-line setting for stage IV renal carcinoma who developed trismus under treatment. The occurrence of this off-target toxicity has made the patient ineligible for anti-angiogenic drugs. Although side effects of tyrosine kinase inhibitors seem manageable and reversible, some less known and unusual effects may evolve into severe and irreversible complications.

Prognostic value of the endothelial activation and stress index in patients with upper tract urothelial cancer undergoing radical nephroureterectomy

Purpose

The relationship with endothelial activation and stress index (EASIX), which represents the degree of endothelial dysfunction, is unwell known in upper tract urothelial carcinoma (UTUC). The present study aims to assess the prognostic value of the EASIX for recurrence-free survival (RFS) and overall survival (OS) in patients with UTUC who underwent radical nephroureterectomy (RNU).

Materials and Methods

We retrospectively reviewed the clinical data of 627 patients with UTUC who underwent RNU without neoadjuvant chemotherapy at three hospitals between 2002 and 2019. EASIX scores were calculated using the formula “serum lactate dehydrogenase (U/L)×creatinine (mg/dL)/platelet count (10⁹/L)” and evaluated based on log₂-transformed values. We divided the patients according to the EASIX score (>1.27 vs. ≤1.27).

Results

Among 627 patients, 380 were finally analyzed. Using maximally selected log-rank statistics, the optimal EASIX cutoff value was 1.27 on the log₂ scale. The baseline characteristics were similar between the two groups except for age. The high EASIX score group had worse RFS and OS than the low EASIX score group (log-rank p=0.001 and p=0.006, respectively). At 5 years, the mean RFS and OS difference between the low and high EASIX score groups was 11.1 and 7.35 months, respectively. High EASIX score remained a key prognosticator of RFS and OS after RNU in multivariable analysis.

Conclusions

EASIX score may represent endothelial dysfunction in patients with UTUC and may serve as a readily available prognostic factor for oncologic outcomes.

Sorafenib: key lessons from over 10 years of experience

Introduction: In 2005, sorafenib was the first targeted therapy approved for advanced renal cell carcinoma (RCC), transforming treatment. In hepatocellular carcinoma (HCC), for more than a decade, sorafenib remained the only approved systemic therapy to have demonstrated a survival benefit in first-line unresectable HCC. In 2013, sorafenib was the first targeted agent approved for patients with differentiated thyroid cancer (DTC) refractory to radioactive iodine treatment. Areas covered: This review discusses the development, advances, and challenges associated with sorafenib use in RCC, HCC, and DTC over the past decade. A search was performed on PubMed and key congresses as required, with no time limits. Expert commentary: Sorafenib has had a lasting impact on the therapeutic landscape of RCC, HCC, and DTC, and remains an important treatment option despite a rapidly evolving treatment landscape. Extensive clinical and real-world experience has been invaluable in improving patient management and maximizing benefit from treatment. Ongoing clinical trials continue to evaluate sorafenib in different settings, and in combination with other therapies in HCC and DTC. We have no doubt that sorafenib will continue to be an important treatment option in the coming years.

Local recurrence of renal cell carcinoma that simulated multiple renal arteriovenous fistulas after laparoscopic partial nephrectomy: Report of a rare case

Herein we report a patient who was initially thought to have renal arteriovenous fistulas 3 months after laparoscopic partial nephrectomy for a small renal mass. After timely intervention using selective renal artery embolization, computed tomography 9 months post-surgery showed persistent renal arteriovenous fistulas and nodular lesions in the perirenal fat. The patient then underwent radical nephrectomy, and histopathological examination showed underlying recurrent clear cell renal cell carcinoma invading the intraparenchymal arteries and veins, which was simulating multiple high-flow renal arteriovenous fistulas.

In Vitro and In Vivo Evaluation of Targeted Sunitinib-Loaded Polymer Microbubbles Against Proliferation of Renal Cell Carcinoma

OBJECTIVES

The poor safety profile of sunitinib capsules has encouraged the identification of targeted drug delivery systems against renal cell carcinoma. This study aimed to explore the effect of sunitinib-loaded microbubbles along with ultrasound (US) treatment on proliferation and apoptosis of human GRC-1 granulocyte renal carcinoma cells in vitro and in vivo (xenograft tumor growth in nude mice).

METHODS

Liposomes containing sunitinib were prepared by using the transmembrane ammonium sulfate gradient method and then absorbed into polymer microbubbles to generate sunitinib-loaded microbubbles. Entrapment of sunitinib was verified by 25-25-[N-[(7-nitro-2-1,3-benzoxadiazol-4-yl)methyl]amino]-27-norcholesterol staining. GRC-1 cells were treated with microbubbles alone, liposomes alone, sunitinib alone, sunitinib-loaded microbubbles without and with US, and no treatment (control). Cell survival and apoptosis were assessed at 12, 24, and 48 hours after treatment. Xenograft tumors were induced by implantation of GRC-1 cells in nude mice. The animals with tumors were then randomly assigned to sunitinib alone, sunitinib-loaded microbubbles - US, sunitinib-loaded microbubbles + US, and no treatment (control; n = 10 per group). The tumor volumes were analyzed on the 7th, 15th, and 21st days.

RESULTS

The sunitinib entrapment efficiency in the liposomes was approximately 78%. The effective sunitinib concentration in each group was 0.1 μg/mL. The sunitinib-loaded microbubble + US group showed a lower in vitro cell survival rate (P < .001) compared with the other groups. Greater in vivo inhibition of xenograft tumor growth was also observed in the sunitinib-loaded microbubble + US group compared with the other groups.

CONCLUSIONS

Combined sunitinib-loaded microbubbles and US treatment significantly inhibits growth of renal carcinoma cells both in vitro and in vivo.

Loss of Jak2 impairs endothelial function by attenuating Raf-1/MEK1/Sp-1 signaling along with altered eNOS activities

A number of inhibitors have been used to dissect the functional relevance of Jak2 in endothelial homeostasis, with disparate results. Given that Jak2 deficiency leads to embryonic lethality, the exact role of Jak2 in the regulation of postnatal endothelial function is yet to be fully elucidated. We generated a model in which Jak2 deficiency can be induced by tamoxifen in adult mice. Loss of Jak2 significantly impaired endothelium-dependent response capacity for vasodilators. Matrigel plug assays indicated a notable decrease in endothelial angiogenic function in Jak2-deficient mice. Studies in a hindlimb ischemic model indicated that Jak2 activity is likely to be a prerequisite for prompt perfusion recovery, based on the concordance of temporal changes in Jak2 expression during the course of ischemic injury and perfusion recovery. A remarkable delay in perfusion recovery, along with reduced capillary and arteriole formation, was observed in Jak2-deficient mice. Antibody array studies indicated that loss of Jak2 led to repressed eNOS expression. In mechanistic studies, Jak2 deficiency attenuated Raf-1/MEK1 signaling, which then reduced activity of Sp-1, an essential transcription factor responsible for eNOS expression. These data are important not only for understanding the exact role that Jak2 plays in endothelial homeostasis, but also for assessing Jak2-based therapeutic strategies in a variety of clinical settings.

Impact of tumor vascularity on responsiveness to antiangiogenesis in a prostate cancer stem cell-derived tumor model

Drugs that target the tumor vasculature and inhibit angiogenesis are widely used for cancer treatment. Individual tumors show large differences in vascularity, but it is uncertain how these differences affect responsiveness to antiangiogenesis. We investigated this question using two closely related prostate cancer models that differ markedly in tumor vascularity: PC3, which has very low vascularity, and the PC3-derived cancer stem-like cell holoclone PC3/2G7, which forms tumors with high microvessel density, high tumor blood flow, and low hypoxia compared with parental PC3 tumors. Three angiogenesis inhibitors (axitinib, sorafenib, and DC101) all induced significantly greater decreases in tumor blood flow and microvessel density in PC3/2G7 tumors compared with PC3 tumors, as well as significantly greater decreases in tumor cell proliferation and cell viability and a greater increase in apoptosis. The increased sensitivity of PC3/2G7 tumors to antiangiogenesis indicates they are less tolerant of low vascularity and suggests they become addicted to their oxygen- and nutrient-rich environment. PC3/2G7 tumors showed strong upregulation of the proangiogenic factors chemokine ligand 2 (CCL2) and VEGFA compared with PC3 tumors, which may contribute to their increased vascularity, and they have significantly lower endothelial cell pericyte coverage, which may contribute to their greater sensitivity to antiangiogenesis. Interestingly, high levels of VEGF receptor-2 were expressed on PC3 but not PC3/2G7 tumor cells, which may contribute to the growth static response of PC3 tumors to VEGF-targeted antiangiogenesis. Finally, prolonged antiangiogenic treatment led to resumption of PC3/2G7 tumor growth and neovascularization, indicating these cancer stem-like cell-derived tumors can adapt and escape from antiangiogenesis.

Vitamin D3 triggers antitumor activity through targeting hedgehog signaling in human renal cell carcinoma

Human clear cell renal cell carcinoma (CCC) remains resistant to treatments despite the progress in targeted therapies. Several signaling pathways acting during renal development are reactivated during kidney tumorigenesis; this is the case of the sonic hedgehog (SHH)-Gli. Interestingly, the precursor of active vitamin D3 (VD3), cholecalciferol, has been demonstrated to be a strong inhibitor of SHH-Gli signaling. Here, we show the preclinical efficacy of cholecalciferol in CCC both in vitro and in vivo. A panel of CCC cell lines, tumors and normal corresponding tissues from CCC patients were used to evaluate the expression of the VD3 receptor and metabolizing enzymes and the effects of cholecalciferol treatment. Subsequently, xenografted mice were treated with cholecalciferol in a prophylactic or therapeutic manner; their response and the adverse effects were evaluated on the basis of weekly monitoring, followed by blood collection procedures and X-ray micro-computed tomography. VD3 receptor and metabolizing enzymes are dramatically decreased in human cell lines and tumors. Cholecalciferol decreases cell proliferation and increases cell death by inhibition of the SHH-Gli pathway. Xenografted mice treated with cholecalciferol exhibit absence of tumor development or substantial growth inhibition. The treatment was shown to be safe; it did not induce calcification or calcium reabsorption. These findings establish that, although VD3 receptors and metabolizing enzymes are absent in CCC, cholecalciferol supplementation is a strong tool to block the reactivation of SHH-Gli pathway in this pathology, leading ultimately to tumor regression. Cholecalciferol may have highly therapeutic potential in CCC.