Targeted therapy for metastatic renal cell carcinoma: current treatment and future directions

Clinical Importance of Focal Adhesion Kinase (FAK)-Src and Paxillin Expression in Renal Cell Carcinoma

BACKGROUND AND OBJECTIVE

The complex focal adhesion kinase (FAK)/Src and paxillin seem to play a key role in the pathogenesis and progression of cancer. The aim of this study is to evaluate the expression of these proteins in renal cell carcinomas (RCCs), considering the immunoreactive score (IRS), the positivity and the intensity, and to find any association with patients' clinical characteristics, histologic type and other pathological features that imply a possible pathophysiological or prognostic role of FAK/Src and paxillin in RCC.

METHODS

Patients with RCC who had undergone partial or radical nephrectomy from January 2009 to September 2010 were eligible for this retrospective cross-sectional study. The immunohistochemical expression of FAK, Src and paxillin proteins in formalin-fixed paraffin-embedded tumour tissue was analysed in association with various clinicopathological features.

RESULTS

Out of ninety patients, 58 had clear cell renal carcinoma, 15 had papillary, 11 had chromophobe and six had unclassified RCC. FAK, Src and paxillin were expressed in 55.6%, 32.2% and 18.9% of all cases, respectively. In univariate analysis, FAK positivity and IRS were more likely in patients with papillary and chromophobe histologic type versus clear cell RCC (p<0.005), Src positivity and IRS presented more frequently in stage T3 versus T1 (p<0.005) and paxillin positivity was more likely in patients with stage T3 versus T2 (p=0.021) and grades 3-4 versus grade 2 (p=0.013). Paxillin-IRS was not associated with any clinicopathological features. The same associations were also reproduced in the multifactorial analysis for the FAK and Src positivity and IRS, while it was found that paxillin positivity and IRS were associated with the female gender (p=0.052, p=0.024), and were higher in grades 3-4 versus grade 2 (p=0.022, p=0.020).

CONCLUSIONS

Our study suggests that RCC shows immunohistochemical expression of FAK, Src and paxillin proteins, and this expression varies in relation to the histologic type, the stage and the stage/grade/gender, respectively. These findings imply a possible involvement of the FAK/Src signalling pathway in the pathogenesis and progression of cancer in RCC, providing future perspectives for targeted therapies with inhibitors.

Precision Medicine: An Optimal Approach to Patient Care in Renal Cell Carcinoma

Renal cell cancer (RCC) is a heterogeneous tumor that shows both intra- and inter-heterogeneity. Heterogeneity is displayed not only in different patients but also among RCC cells in the same tumor, which makes treatment difficult because of varying degrees of responses generated in RCC heterogeneous tumor cells even with targeted treatment. In that context, precision medicine (PM), in terms of individualized treatment catered for a specific patient or groups of patients, can shift the paradigm of treatment in the clinical management of RCC. Recent progress in the biochemical, molecular, and histological characteristics of RCC has thrown light on many deregulated pathways involved in the pathogenesis of RCC. As PM-based therapies are rapidly evolving and few are already in current clinical practice in oncology, one can expect that PM will expand its way toward the robust treatment of patients with RCC. This article provides a comprehensive background on recent strategies and breakthroughs of PM in oncology and provides an overview of the potential applicability of PM in RCC. The article also highlights the drawbacks of PM and provides a holistic approach that goes beyond the involvement of clinicians and encompasses appropriate legislative and administrative care imparted by the healthcare system and insurance providers. It is anticipated that combined efforts from all sectors involved will make PM accessible to RCC and other patients with cancer, making a tremendous positive leap on individualized treatment strategies. This will subsequently enhance the quality of life of patients.

Analysis of Clinicopathological Factors Influencing Survival in Patients with Renal Cell Carcinoma and Venous Tumor Thrombus

This study aimed to define patients with renal cell cancer and coexisting tumor thrombus in order to address concerns regarding survival and prognostic factors after radical surgery. Several prognostic factors for overall survival (OS) were assessed in patients treated surgically at five institutions from 2012 to 2018. Univariate and multivariate analyses were used to determine the independent risk factors of OS. A total of 142 patients were eligible for further analysis (mean age of 64.75 years, 56% males). Most patients presented with clear cell carcinoma (95%). The Mayo stage was predominantly 0–1 (88%). Distant visceral metastases at the time of diagnosis were present in 36 patients (25%), whereas nodal metastases were present in 24 patients (16.9%). During the follow-up period (mean of 32.5 months), the 3-year OS rate reached 68.2%. The majority of patients received no adjuvant treatment (n = 107). In a multivariable model predicting OS, regional lymph node status (p < 0.001), distant metastases (p = 0.009), tumor grade (p = 0.002), duration of hospitalization (p = 0.016), and Clavien–Dindo grade (p = 0.047) were identified as independent prognostic factors. A subgroup of patients with specific clinicopathological factors may benefit most from the radical surgery, including patients without regional lymph node or distant metastases and with low tumor grades, whereas short hospitalization and low Clavien–Dindo grades represent additional independent prognostic factors.

Sonic Hedgehog gene as a potential target for the early prophylactic detection of cancer

In the search for newer and advanced methods for the detection of cancer, quicker and non-invasive techniques are imperative. One such potential approach for detection is the detection of oncogenes in the suspected tumour tissues. This search has led to the identification of the oncogene SHh, which is a key influencer in the tumourigenic pathways. Therefore, a cancer detection method, which would target the identification of the oncogene SHh would therefore be a step forward in the advancement of cancer research.

Controlled Tyrosine Kinase Inhibitor Delivery to Liver Cancer Cells by Gate-Capped Mesoporous Silica Nanoparticles

Hepatocellular carcinoma is the most common type of primary malignancy in the liver and one of the most common types of cancer worldwide. Its readily increasing mortality rate highlights the urgent need for the development of efficient therapeutic strategies. Tyrosine kinase inhibitors (TKIs) such as sorafenib and sunitinib are used as efficient angiogenesis inhibitors for this purpose. However, despite their pharmacological effects, their transfer into clinical practice is characterized by their poor aqueous solubility and accumulation in off-target tissues, resulting in unfavorable side effects. Here, we report a nanocomposite made of amine-functionalized mesoporous silica nanocomposites (MSNs) that are surface-coated with cerium oxide nanoparticles (CNPs) for the controlled delivery and release of TKIs. Amine-functionalized MSNs were prepared using a sol-gel method and loaded with TKIs. To trap drug molecules into the mesoporous structure, CNPs were covalently conjugated to the surface of MSNs. The synthesis and functionalization steps were controlled using different characterization methods, confirming the desired morphology and structure, the identity of functional groups on the surface, successful coating, and appropriate loading efficiency. Under physiological conditions, CNP-capped MSNs demonstrated a sustained drug release over time as a result of CNPs' gatekeeping effect on the payloads. Strong cellular interactions with different liver cancer cells and enhanced cellular uptake were also observed in vitro for the gate-capped MSNs. Internalization of nanocomposites induced cell death via the production of reactive oxygen species, and subsequent activation of apoptosis pathways. This study demonstrates that gate-capped MSNs are promising chemotherapeutic vehicles characterized by a sustained drug release profile and high cellular internalization.

Combination of mTOR and MAPK Inhibitors-A Potential Way to Treat Renal Cell Carcinoma

Renal cell carcinoma (RCC) is the most common neoplasm that occurs in the kidney and is marked by a unique biology, with a long history of poor response to conventional cancer treatments. In the past few years, there have been significant advancements to understand the biology of RCC. This has led to the introduction of novel targeted therapies in the management of patients with metastatic disease. Patients treated with targeted therapies for RCC had shown positive impact on overall survival, however, no cure is possible and patients need to undergo treatment for long periods of time, which raises challenges to manage the associated adverse events. Moreover, many patients may not respond to it and even response may not last long enough in the responders. Many inhibitors of the Mammalian target of Rapamycin (mTOR) signaling pathway are currently being used in treatment of advanced RCC. Studies showed that inhibitions of mTOR pathways induce Mitogen-Activated Protein Kinase (MAPK) escape cell death and cells become resistant to mTOR inhibitors. Because of this, there is a need to inhibit both pathways with their inhibitors comparatively for a better outcome and treatment of patients with RCC.

Molecular Targeting of Integrins and Integrin-Associated Signaling Networks in Radiation Oncology

Radiation and chemotherapy are the main pillars of the current multimodal treatment concept for cancer patients. However, tumor recurrences and resistances still hamper treatment success regardless of advances in radiation beam application, particle radiotherapy, and optimized chemotherapeutics. To specifically intervene at key recurrence- and resistance-promoting molecular processes, the development of potent and specific molecular-targeted agents is demanded for an efficient, safe, and simultaneous integration into current standard of care regimens. Potential targets for such an approach are integrins conferring structural and biochemical communication between cells and their microenvironment. Integrin binding to extracellular matrix activates intracellular signaling for regulating essential cellular functions such as survival, proliferation, differentiation, adhesion, and cell motility. Tumor-associated characteristics such as invasion, metastasis, and radiochemoresistance also highly depend on integrin function. Owing to their dual functionality and their overexpression in the majority of human malignancies, integrins present ideal and accessible targets for cancer therapy. In the following chapter, the current knowledge on aspects of the tumor microenvironment, the molecular regulation of integrin-dependent radiochemoresistance and current approaches to integrin targeting are summarized.

Current management and future directions in the treatment of advanced renal cell carcinoma-a latin american perspective: 10 years in review

The worldwide incidence of kidney cancer is estimated at 337,860 new cases per year in the International Agency for Research on Cancer's GLOBOCAN 2012 update, with an estimated 143,369 deaths annually. Over the past 10 years, there have been significant advances in the treatment of advanced/metastatic renal cell carcinoma, including the development of targeted therapies. Currently recommended first-line treatments include sunitinib, temsirolimus, bevacizumab plus interferon, and pazopanib, or high-dose interleukin-2 or sorafenib for selected patients. Recommended second-line treatments include all of the above agents, as well as everolimus and axitinib. Unfortunately, combination therapies have generally resulted in increased toxicity and little improvement in efficacy. Recent studies focused on identification of predictive biomarkers for responses to specific targeted therapies and have not been successful to date. Despite recent advances in targeted treatment for metastatic renal cell carcinoma, important questions regarding biomarkers of efficacy, and optimal combination and sequencing of agents remain to be answered. This paper reviews literature concerned with first-and second-line treatment of metastatic renal cell carcinoma and will discuss key issues in Latin America.

Whole lesion quantitative CT evaluation of renal cell carcinoma: differentiation of clear cell from papillary renal cell carcinoma

Purpose

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of renal cell cancer (RCC), followed by papillary RCC (pRCC). It is important to distinguish these two subtypes because of prognostic differences and possible changes in management, especially in cases undergoing active surveillance. The purpose of our study is to evaluate the use of voxel-based whole-lesion (WL) enhancement parameters on contrast enhanced computed tomography (CECT) to distinguish ccRCC from pRCC.

Materials and methods

In this institutional review board-approved study, we retrospectively queried the surgical database for post nephrectomy patients who had pathology proven ccRCC or pRCC and who had preoperative multiphase CECT of the abdomen between June 2009 and June 2011. A total of 61 patients (46 with ccRCC and 15 with pRCC) who underwent robotic assisted partial nephrectomy for clinically localized disease were included in the study. Multiphase CT acquisitions were transferred to a dedicated three-dimensional workstation, and WL regions of interest were manually segmented. Voxel-based contrast enhancement values were collected from the lesion segmentation and displayed as a histogram. Mean and median enhancement and histogram distribution parameters skewness, kurtosis, standard deviation, and interquartile range were calculated for each lesion. Comparison between ccRCC and pRCC was made using each imaging parameter. For mean and median enhancement, which had a normal distribution, independent t-test was used. For histogram distribution parameters, which were not normally distributed, Wilcoxon rank sum test was used.

Results

ccRCC had significantly higher mean and median whole WL enhancement (p < 0.01) compared to pRCC on arterial, nephrographic, and excretory phases. ccRCC had significantly higher interquartile range and standard deviation (p < 0.01) and significantly lower skewness (p < 0.01) compared to pRCC on arterial and nephrographic phases. ccRCC had significantly lower kurtosis compared to pRCC on only the arterial phase.

Conclusion

Our study suggests that voxel-based WL enhancement parameters can be used as a quantitative tool to differentiate ccRCC from pRCC. Differentiating between the two main types of RCC would provide the patient and the treating physicians more information to formulate the initial approach to managing the patient’s renal cancer.

Inhibition of proliferation and migration of luminal and claudin-low breast cancer cells by PDGFR inhibitors

BACKGROUND

Platelet-derived growth factors (PDGFs) bind to two receptors, PDGFRα and PDGFRβ to mediate cell proliferation, migration and survival. Although epithelial cells typically do not express high levels of PDGFRs, their expression has been reported to increase in breast cancer cells that have undergone epithelial to mesenchymal transition.

METHODS

PDGFR signaling was inhibited using Sunitinib malate, Imatinib mesylate or Regorafenib in murine and human luminal-like and claudin-low mammary tumor cell lines or Masitinib in only the human cell lines. A scratch wound assay was used to assess tumor cell migration while immunofluorescence for phosphorylated histone H3 or cleaved caspase 3 was used to determine tumor cell proliferation and apoptosis, respectively.

RESULTS

Sunitinib and Regorafenib, but not Imatinib, were capable of significantly inhibiting the migration of both murine and human luminal-like and claudin-low breast cancer cells while Masitinib inhibited migration in both human breast cancer cell lines. Sunitinib but not Regorafenib or Imatinib also significantly suppressed tumor cell proliferation in all four cell lines tested while Masitinib had no significant effect on human breast cancer cell proliferation. None of the PDGFR inhibitors consistently regulated mammary tumor cell apoptosis.

CONCLUSION

Sunitinib, Regorafenib and Masitinib may prove clinically useful in inhibiting breast cancer cell migration and metastasis while only Sunitinib (and possibly Regorafenib in some breast cancer subtypes) is effective at inhibiting both migration and proliferation of breast cancer cells.

Emerging antiangiogenics for renal cancer

INTRODUCTION

Antiangiogenic therapy is considered to be the backbone of treatment strategy in metastatic renal cell carcinoma (mRCC). New, more focused, targeted drugs are emerging, while other targeted drugs oriented toward resistance or alternative mechanisms are under development.

AREAS COVERED

Antiangiogenic agents include two types of agents: the monoclonal antibody, targeting vascular endothelial growth factor (VEGF), bevacizumab and the tyrosine kinase inhibitors (TKIs). Data regarding efficacy and safety of these agents are reported. Differences between the first generation of TKIs, sunitinib, sorafenib, and the new generation, pazopanib, axitinib and tivozanib are also detailed. Most of these agents have been approved in the treatment of kidney cancer in specific settings of the disease.

EXPERT OPINION

The class of antiangiogenic drugs for treatment of mRCC is already relatively full. After 'me-too' drugs, more targeted drugs against VEGFR have been developed but have to demonstrate a benefit in first-line treatment. Another option for the development is to combine a known drug with an antiangiogenic inhibition profile and at least one additional target involved in resistance to an antiangiogenic or in an alternative pathway. The cost of approach with targeted drugs, including antiangiogenics, has led to a tremendous increase in the cost of care in mRCC.

Tivozanib reverses multidrug resistance mediated by ABCB1 (P-glycoprotein) and ABCG2 (BCRP)

AIM

This study aimed to investigate the mechanism of reversal of multidrug resistance mediated by ABC transporters with tivozanib (AV-951 and KRN-951). Tivozanib is a potent inhibitor of VEGF-1, -2 and -3 receptors.

MATERIALS & METHODS

ABCB1- and ABCG2-overexpressing cell lines were treated with respective substrate antineoplastic agents in the presence or absence of tivozanib.

RESULTS

The results indicate that tivozanib can significantly reverse ABCB1-mediated resistance to paclitaxel, vinblastine and colchicine, as well as ABCG2-mediated resistance to mitoxantrone, SN-38 and doxorubicin. Drug efflux assays showed that tivozanib increased the intracellular accumulation of substrates by inhibiting the ABCB1 and ABCG2 efflux activity. Furthermore, at a higher concentration, tivozanib inhibited the ATPase activity of both ABCB1 and ABCG2 and inhibited the photolabeling of ABCB1 or ABCG2.

CONCLUSION

We conclude that tivozanib at noncytotoxic concentrations has the previously unknown activity of reversing multidrug resistance mediated by ABCB1 and ABCG2 transporters.

Metastatic renal cell carcinoma: update on epidemiology, genetics, and therapeutic modalities

The treatment of advanced renal cell carcinoma (RCC) remains a major therapeutic challenge for clinicians. Despite advances in the understanding of the immunobiology of RCC and the availability of several novel targeted agents, there has been little improvement in the survival of patients with metastatic RCC. This review will focus on the recent understanding of risk factors and treatment options and outcomes of metastatic RCC, in particular, targeted therapeutic agents that inhibit vascular endothelial growth factor and mammalian target of rapamycin pathways. Prospective studies are required to determine whether sequential targeted therapy will further improve progression-free survival in RCC. Ongoing research to develop novel agents with better tolerability and enhanced efficacy in the treatment of metastatic RCC is required.