The role of RNA modification in urological cancers: mechanisms and clinical potential

RNA modification is a post-transcriptional level of regulation that is widely distributed in all types of RNAs, including mRNA, tRNA, rRNA, miRNA, and lncRNA, where N6-methyladenine (m6A) is the most abundant mRNA methylation modification. Significant evidence has depicted that m6A modifications are closely related to human diseases, especially cancer, and play pivotal roles in RNA transcription, splicing, stabilization, and translation processes. The most common urological cancers include prostate, bladder, kidney, and testicular cancers, accounting for a certain proportion of human cancers, with an ever-increasing incidence and mortality. The recurrence, systemic metastasis, poor prognosis, and drug resistance of urologic tumors have prompted the identification of new therapeutic targets and mechanisms. Research on m6A modifications may provide new solutions to the current puzzles. In this review, we provide a comprehensive overview of the key roles played by RNA modifications, especially m6A modifications, in urologic cancers, as well as recent research advances in diagnostics and molecularly targeted therapies.

Update on First-Line Combination Treatment Approaches in Metastatic Clear-Cell Renal Cell Carcinoma

OPINION STATEMENT

The treatment for metastatic renal cell carcinoma (mRCC) has significantly evolved in recent years with a deeper understanding of the molecular make-up of the disease and the clinical development of therapies with novel mechanisms of action. While some patients with more indolent disease may benefit from local therapy such as metastasectomy or cytoreductive nephrectomy, others may safely embark on an active surveillance program or be offered targeted therapy. Yet, a combination regimen including an ICI is the most effective regimen and should be considered in most mRCC cases. Ongoing studies will help determine which factors can be further used to optimize treatment selection and personalize disease management.

Current updates and future perspectives on the management of renal cell carcinoma

Renal cell carcinoma (RCC) refers to renal-epithelial cancer, which represents over 90% of kidney cancer and is a cause for cancer related deaths in the world. Studies suggested somatic VHL mutations to be the cause for the occurrence of cancer, but with the time, more latest genomic and biological studies have detected variation in epigenetic regulatory genes and showed significant heterogeneity of the intratumor that may lead to strategies of diagnostic, predictive, and therapeutic importance. Immune dysfunction is responsible for almost all types of renal cancer, and angiogenesis and immunosuppression function together in the tumor microenvironment of renal cell carcinoma (RCC). Over the past few years, advancement in the management of the RCC has finally revolutionized with the arrival of the entrapped immune inhibitors which particularly concentrated on the receptor (programmed cell death-1) and focus on the new generation receptor i.e. TKRI (tyrosine-kinase receptor inhibitors). The present review deals with the comprehensive review of RCC and emphasizes on its types, pathogenesis and advancement in these diseases. This review also overviews the role of innate and adaptive immune response-related mechanism, the function of cancer stem cell in this diseases, therapeutic targeted drugs and hormonal signaling pathways as an emerging strategy in the management of the renal cancer.

Spectral Computed Tomographic Parameters Predict the Therapeutic Efficacy and Overall Survival of the Angiogenesis Inhibitor AL3818 in Hepatic Lesions: Preliminary Animal Study

OBJECTIVE

This study aimed to investigate the predictive and prognostic values of repeated spectral computed tomographic (CT) parameter changes for the prediction of treatment responses to the angiogenesis inhibitor AL3818 in hepatic tumors.

METHODS

A total of 30 rabbits with VX2 hepatic tumors that underwent spectral contrast-enhanced abdominal CT before and during treatment were included in the study. The percent change (Δ, %) of the normalized iodine concentration (nIC) during the arterial phase (AP) and venous phase (VP) was used to predict the tumor response and to calculate the overall survival (OS). The threshold of the nIC for tumor response prediction and prognostic significance was determined by a receiver operating characteristic curve and Kaplan-Meier analysis.

RESULTS

After treatment, there were 43% (13/30) responders and 57% (17/30) nonresponders. When ΔnICAP ≥ -13.10% was used as the threshold, the sensitivity and specificity for the prediction of tumor response were 82.41% and 92.31%, respectively. ΔnICVP resulted in 88.20% sensitivity and 76.92% specificity for cutoff values ≥10.78%. Kaplan-Meier analyses showed that high ΔnICAP and ΔnICVP were associated with improved OS.

CONCLUSIONS

The current study shows the capability of the changes (Δ) in repeated spectral CT parameters to predict the tumor response during antiangiogenesis therapy in small hepatic tumors. ΔnICAP and ΔnICVP were predictors for treatment response and were associated with OS.

Drug-induced hepatotoxicity in cancer patients - implication for treatment

INTRODUCTION

All anticancer drugs can cause idiosyncratic liver injury. Therefore, hepatoprotective agents assume particular importance to preserve liver function. Hepatic injury represents 10% of cases of acute hepatitis in adults; drug-related damage is still misjudged because of relative clinical underestimation and difficult differential diagnosis. Chemotherapeutic agents can produce liver toxicity through different pathways, resulting in different categories of liver injuries, but these drugs are not homogeneously hepatotoxic. Frequently, anticancer-induced hepatotoxicity is idiosyncratic and influenced by multiple factors.

AREAS COVERED

The aim of this paper is to perform a review of the literature regarding anticancer-induced liver toxicity. We described hepatotoxicity mechanisms of principal anticancer agents and respective dose reductions. Furthermore, we reviewed studies on hepatoprotectors and their optimal use. Tiopronin, magnesium isoglycyrrhizinate and S-Adenosylmethionine (AdoMet) demonstrated, in some small studies, a potential hepatoprotective activity.

EXPERT OPINION

Actually, in the literature only small experiences are reported. Even though hepatoprotective agents seem to be useful in the oncologic setting, the lack of well-designed prospective Phase III randomized controlled trials is a major limit in the introduction of hepatoprotectors in cancer patients and these kind of studies are warranted to support their use and to give further recommendations for the clinical practice.

VB-111: a novel anti-vascular therapeutic for glioblastoma multiforme

Glioblastoma multiforme (GBM) is among the most highly vascularized of solid tumors, contributing to the infiltrative nature of the disease, and conferring poor outcome. Due to the critical dependency of GBM on growth of new endothelial vasculature, we evaluated the preclinical activity of a novel adenoviral gene therapy that targets the endothelium within newly formed blood vessels for apoptosis. VB-111, currently in phase II clinical trials, consists of a non-replicating Adenovirus 5 (El deleted) carrying a proapoptotic human Fas-chimera (transgene) under the control of a modified murine promoter (PPE-1-3×) which specifically targets endothelial cells within the tumor vasculature. Here we report that a single intravenous dose of 2.5 × 10(11) or 1 × 10(11) VPs was sufficient to extend survival in nude rats bearing U87MG-luc2 or nude mice bearing U251-luc, respectively. Bioluminescence imaging of nude rats showed that VB-111 effectively inhibited tumor growth within four weeks of treatment. This was confirmed in a select group of animals by MRI. In our mouse model we observed that 3 of 10 nude mice treated with VB-111 completely lost U251 luciferase signal and were considered long term survivors. To assess the antiangiogenic effects of VB-111, we evaluated the tumor-associated microvaculature by CD31, a common marker of neovascularization, and found a significant decrease in the microvessel density by IHC. We further assessed the neovasculature by confocal microscopy and found that VB-111 inhibits vascular density in two separate mouse models bearing U251-RFP xenografts. Collectively, this study supports the clinical development of VB-111 as a treatment for GBM.

Bevacizumab did not reduce the risk of anemia associated with chemotherapy: an up-to-date meta-analysis

PURPOSE

The risk of anemia due to bevacizumab-based chemotherapy has not been well described, and new randomized controlled trials (RCTs) have been reported in recent years. We therefore conducted an up-to-date meta-analysis of RCTs to fully characterize the risk of anemia with bevacizumab.

METHODS

We carried out an electronic search of Medline, Embase, and The Cochrane Central Register of Controlled Trials to investigate the effects of RCTs on bevacizumab treatment on cancer patients up to October 2014, and random or fixed-effect meta-analytical models were used to assess the risk ratio (RR) of anemia due to the use of bevacizumab according to the heterogeneity of included studies.

RESULTS

A total of 13,173 patients were included in this analysis from 18 RCTs. Among those patients receiving bevacizumab and chemotherapy, the incidences of all-grade and high-grade (grade 3 and above) anemia were 24% (95% confidence interval (CI) 13-41%) and 4.0% (95% CI 3.0-6.0%), respectively. Bevacizumab-containing therapy did not significantly decreased the risk of developing all-grade anemia (RR 0.872, 95% CI 0.739-1.029, P = 0.104) and high-grade anemia (RR 0.850, 95% CI 0.720-1.002, P = 0.053), which is not in agreement with previous meta-analysis. On subgroup analysis, we did not find significant risk differences based on bevacizumab dosage, tumor types, and concomitant drugs. When stratified by dose level, a significantly decreased risk of high-grade anemia with bevacizumab was obtained in a lower dose level (2.5 mg/kg/week, RR 0.773, 95% CI 0.611-0.978, P = 0.031) compared to control group.

CONCLUSIONS

Bevacizumab did not significantly reduce the risk of anemia with chemotherapy in cancer patients.

Hepatotoxicity of molecular targeted therapy

A constant increase in occurrence of neoplasms is observed; hence new methods of therapy are being intensively researched. One of the methods of antineoplastic treatment is molecular targeted therapy, which aims to influence individual processes occurring in cells. Using this type of medications is associated with unwanted effects resulting from the treatment. Liver damage is a major adverse effect diagnosed during targeted therapy. Drug-induced liver damage can occur as necrosis of hepatocytes, cholestatic liver damage and cirrhosis. Hepatotoxicity is evaluated on the basis of International Consensus Criteria. Susceptibility of the liver to injury is connected not only with toxicity of the used medications but also with metastasis, coexistence of viral infections or other chronic diseases as well as the patient's age. It has been proven that in most cases the liver injury is caused by treatment with multikinase inhibitors, in particular tyrosine kinase inhibitors. The Food and Drug Administration (FDA) ordered the inclusion of additional labels – so-called “black box warnings” – indicating increased risk of liver injury when treating with pazopanib, sunitinib, lapatinib and regorafenib. A meta-analysis published in 2013 showed that treating neoplastic patients with tyrosine kinase inhibitors can increase the risk of drug-induced liver damage at least twofold. Below the mechanisms of drug-induced liver injury and hepatotoxic effects of molecular targeted therapy are described.

Proof-of-concept study of monitoring cancer drug therapy with cerenkov luminescence imaging

Cerenkov luminescence imaging (CLI) has emerged as a less expensive, easier-to-use, and higher-throughput alternative to other nuclear imaging modalities such as PET. It is expected that CLI will find many applications in biomedical research such as cancer detection, probe development, drug screening, and therapy monitoring. In this study, we explored the possibility of using CLI to monitor drug efficacy by comparisons against PET. To assess the performance of both modalities in therapy monitoring, 2 murine tumor models (large cell lung cancer cell line H460 and prostate cancer cell line PC3) were given bevacizumab versus vehicle treatments. Two common radiotracers, 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) and (18)F-FDG, were used to monitor bevacizumab treatment efficacy.

METHODS

One group of mice (n = 6) was implanted with H460 xenografts bilaterally in the shoulder region, divided into treatment and control groups (n = 3 each), injected with (18)F-FLT, and imaged with PET immediately followed by CLI. The other group of mice (n = 6) was implanted with PC3 xenografts in the same locations, divided into treatment and control groups (n = 3 each), injected with (18)F-FDG, and imaged by the same modalities. Bevacizumab treatment was performed by 2 injections of 20 mg/kg at days 0 and 2.

RESULTS

On (18)F-FLT scans, both CLI and PET revealed significantly decreased signals from H460 xenografts in treated mice from pretreatment to day 3. Moderately increased to unchanged signals were observed in untreated mice. On (18)F-FDG scans, both CLI and PET showed relatively unchanged signals from PC3 tumors in both treated and control groups. Quantifications of tumor signals of Cerenkov luminescence and PET images showed that the 2 modalities had excellent correlations (R(2) > 0.88 across all study groups).

CONCLUSION

CLI and PET exhibit excellent correlations across different tumor xenografts and radiotracers. This is the first study, to our knowledge, demonstrating the use of CLI for monitoring cancer treatment. The findings warrant further exploration and optimization of CLI as an alternative to PET in preclinical therapeutic monitoring and drug screening.

Theranostic applications of nanomaterials in cancer: drug delivery, image-guided therapy, and multifunctional platforms

Successful cancer management depends on accurate diagnostics along with specific treatment protocols. Current diagnostic techniques need to be improved to provide earlier detection capabilities, and traditional chemotherapy approaches to cancer treatment are limited by lack of specificity and systemic toxicity. This review highlights advances in nanotechnology that have allowed the development of multifunctional platforms for cancer detection, therapy, and monitoring. Nanomaterials can be used as MRI, optical imaging, and photoacoustic imaging contrast agents. When used as drug carriers, nanoformulations can increase tumor exposure to therapeutic agents and result in improved treatment effects by prolonging circulation times, protecting entrapped drugs from degradation, and enhancing tumor uptake through the enhanced permeability and retention effect as well as receptor-mediated endocytosis. Multiple therapeutic agents such as chemotherapy, antiangiogenic, or gene therapy agents can be simultaneously delivered by nanocarriers to tumor sites to enhance the effectiveness of therapy. Additionally, imaging and therapy agents can be co-delivered to provide seamless integration of diagnostics, therapy, and follow-up, and different therapeutic modalities such as chemotherapy and hyperthermia can be co-administered to take advantage of synergistic effects. Liposomes, metallic nanoparticles, polymeric nanoparticles, dendrimers, carbon nanotubes, and quantum dots are examples of nanoformulations that can be used as multifunctional platforms for cancer theranostics. Nanomedicine approaches in cancer have great potential for clinically translatable advances that can positively impact the overall diagnostic and therapeutic process and result in enhanced quality of life for cancer patients. However, a concerted scientific effort is still necessary to fully explore long-term risks, effects, and precautions for safe human use.

YN968D1 is a novel and selective inhibitor of vascular endothelial growth factor receptor-2 tyrosine kinase with potent activity in vitro and in vivo

Angiogenesis is an important process in cell development, especially in cancer. Vascular endothelial growth factor (VEGF) signaling is an important regulator of angiogenesis. Several therapies that act against VEGF signal transduction have been developed, including YN968D1, which is a potent inhibitor of the VEGF signaling pathway. This study investigated the antitumor activity of YN968D1 (apatinib mesylate) in vitro and in vivo. YN968D1 potently suppressed the kinase activities of VEGFR-2, c-kit and c-src, and inhibited cellular phosphorylation of VEGFR-2, c-kit and PDGFRβ. YN968D1 effectively inhibited proliferation, migration and tube formation of human umbilical vein endothelial cells induced by FBS, and blocked the budding of rat aortic ring. In vivo, YN968D1 alone and in combination with chemotherapeutic agents effectively inhibited the growth of several established human tumor xenograft models with little toxicity. A phase I study of YN968D1 has shown encouraging antitumor activity and a manageable toxicity profile. These findings suggest that YN968D1 has promise as an antitumor drug and might have clinical benefits.

Bevacizumab: in previously treated glioblastoma

Bevacizumab is a recombinant humanized monoclonal IgG(1) antibody that binds to human vascular endothelial growth factor and inhibits angiogenesis and hence tumour growth. It is available in the US and other countries for the treatment of several types of cancer, including glioblastoma that has recurred after previous treatment. Two prospective phase II trials have evaluated bevacizumab 10 mg/kg every 2 weeks for the treatment of previously treated glioblastoma. In the randomized, noncomparative, multicentre AVF3708g trial in patients with glioblastoma in first or second relapse, the rate of progression-free survival at 6 months was 42.6% and the objective response rate was 28.2% in recipients of bevacizumab alone (n = 85). In the bevacizumab plus irinotecan treatment arm (n = 82), the 6-month progression-free survival rate was 50.3% and the objective response rate was 37.8%. These rates were all significantly higher than historical control data. In the supporting, single-arm, single-centre, phase II NCI 06-C-0064E trial of bevacizumab in patients with glioblastoma that had recurred after radiotherapy and temozolomide chemotherapy (n = 48), the rate of progression-free survival at 6 months was 29% and the overall response rate based on Macdonald criteria was 35%. Given the nature of the disease, bevacizumab was generally well tolerated in these two phase II trials. In the AVF3708g trial, grade 3 or higher treatment-emergent adverse events occurred in 46.4% of bevacizumab and 65.8% of bevacizumab plus irinotecan recipients.

[Novel therapeutic targets in metastatic renal cell carcinoma. Results of the treatment with single-agent bevacizumab in a single institution]

AIM

Along the past decade a number of new agents have been developed showing promising results in the treatment of metastatic renal cell carcinoma. We describe our experience with the use of bevacizumab in monotherapy in the Urology and Medical Oncology departments of our institution.

MATERIAL AND METHODS

A consecutive series of patients treated with Bevacizumab 10 mg/Kg every 14 days between January 2006 and January 2008 has been assessed. Data concerning the type of surgery, histological subtype, tumor stage, Motzer's risk group, metastatic sites number of bevacizumab courses given, time to progression and overall survival were collected.

RESULTS

25 patients (16 male, 9 female) were analyzed. Median age was 59 years. Nineteen of them (75%) had prior surgery: radical nephrectomy 14, cytoreductive 4 y tumorectomy 1). Clear cell carcinoma was the most frequent subtype (22 patients). According to Motzer's prognostic index 14 had good prognosis, 8 intermediate and 3 poor prognosis. Median time to progression was 19 weeks. Overall median survival since metastatic disease was diagnosed 8,7 months.

CONCLUSIONS

Bevacizumab offers, as single agent, modest activity in the metastatic renal cell carcinoma. The recently labeled use in combination with interferon as well as the newer targeted agents will improve the results of the treatment of this disease in the next future.