Signaling Inhibitors in Metastatic Renal Cell Carcinoma

Response to post-axitinib treatment in patients with metastatic renal cell carcinoma

BACKGROUND

Axitinib is a potent inhibitor of the vascular endothelial growth factor (VEGF) receptor family with clinical activity in patients with metastatic renal cell carcinoma (mRCC). Given this biochemical potency, the clinical activity of subsequent treatment with targeted therapies in patients progressing on axitinib is of interest.

METHODS

Patients with advanced renal cell carcinoma of any pathologic subtype treated with at least one cycle (four weeks) of axitinib followed by at least one subsequent targeted therapy were investigated in a retrospective analysis. Patient characteristics, duration of treatment and clinical outcomes were analyzed for axitinib and each subsequent line of therapy by Response Evaluation Criteria in Solid Tumors (RECIST).

RESULTS

Twenty-five mRCC patients who received at least one approved targeted agent following axitinib were identified. Eight percent of patients achieved a partial response (one patient each to sunitinib and pazopanib) and 42 % had a best response of stable disease to the first therapy after axitinib. The estimated median duration of therapy was 4.4 months (range, 0.2-27.5+). Twelve patients received a second post-axitinib targeted therapy. Six out of 11 evaluable patients (55 %) had a best response of SD. The estimated median duration of treatment was 4.8 months (range, 0.7-19.1+).

CONCLUSION

Objective responses and stable disease is observed to post-axitinib targeted therapies and prospective studies are needed for validating role of predictive biomarkers.

Targeting FAK scaffold functions inhibits human renal cell carcinoma growth

Human conventional renal cell carcinoma (CCC) remains resistant to current therapies. Focal Adhesion Kinase (FAK) is upregulated in many epithelial tumors and clearly implicated in nearly all facets of cancer. However, only few reports have assessed whether FAK may be associated with renal tumorigenesis. In this study, we investigated the potential role of FAK in the growth of human CCC using a panel of CCC cell lines expressing or not the von Hippel-Lindau (VHL) tumor suppressor gene as well as normal/tumoral renal tissue pairs. FAK was found constitutively expressed in human CCC both in culture cells and freshly harvested tumors obtained from patients. We showed that CCC cell growth was dramatically reduced in FAK-depleted cells or after FAK inhibition with various inhibitors and this effect was obtained through inhibition of cell proliferation and induction of cell apoptosis. Additionally, our results indicated that FAK knockdown decreased CCC cell migration and invasion. More importantly, depletion or pharmacological inhibition of FAK substantially inhibited tumor growth in vivo. Interestingly, investigations of the molecular mechanism revealed loss of FAK phosphorylation during renal tumorigenesis impacting multiple signaling pathways. Taken together, our findings reveal a previously uncharacterized role of FAK in CCC whereby FAK exerts oncogenic properties through a non canonical signaling pathway involving its scaffolding kinase-independent properties. Therefore, targeting the FAK scaffold may represent a promising approach for developing innovative and highly specific therapies in human CCC.

Sorafenib as first- or second-line therapy in patients with metastatic renal cell carcinoma in a community setting

ABSTRACT Aim: The Italian Retrospective Analysis of Sorafenib as First or Second Target Therapy study assessed the efficacy and safety of sorafenib in metastatic renal cell carcinoma patients treated in the community. Patients & methods: Patients receiving first- or second-line single-agent sorafenib between January 2008 and December 2010 were eligible. Retrospective data collection started in 2012 and covers at least 1-year follow-up. The primary end point was overall survival (OS). Results: Median OS was 17.2 months (95% CI: 15.5–19.6): 19.9 months (95% CI: 15.9–25.3) in patients treated with first-line sorafenib and 16.3 months (95% CI: 13.1–18.2) with second-line sorafenib. Overall median (95% CI) progression-free survival was 5.9 months (95% CI: 4.9–6.7): 6.6 (95% CI: 4.9–9.3) and 5.3 months (95% CI: 4.3–6.0) in first- and second-line patients, respectively. Conclusion: The efficacy and safety of sorafenib in routine community practice was generally good, especially in relation to OS in patients treated in the second line, where results were similar to those seen in recent prospective clinical trials.

Ancillary diagnostic techniques in the evaluation of adult epithelial renal neoplasms: indications, caveats, and pitfalls

The role played currently by the different ancillary diagnostic techniques in the diagnosis of adult epithelial renal tumors continues to be debated. It has also become clear that in some instances light microscopic appearance alone cannot be used to classify these neoplasms into specific categories with the degree of precision required for therapeutic purposes. Renal cell carcinoma (RCC) subtypes may share common histologic characteristics but exhibit different biological behavior and response to therapy which clearly indicates the crucial role that advanced pathologic speciation plays in the current assessment of these neoplasms. Although immunohistochemistry is widely used for the purpose of categorizing renal tumors because of its widespread availability, the immunoprofiles of the various types of renal neoplasms overlap significantly, making definitive diagnostic determinations difficult and challenging at times. This manuscript will address how ancillary diagnostic techniques can be incorporated into the routine evaluation of neoplastic renal masses to improve classification. Both cytology and surgical specimens will be addressed, as fine needle aspiration (FNA) is being used with preference in many cases in the diagnosis of renal masses. Surgical and cytopathologists must intelligently select the ancillary diagnostic technique/s that will provide the information needed to solve the differential diagnosis under consideration in a given case. However, in some cases >1 of these techniques should be used to make an accurate diagnosis with the aim of arriving at an unequivocal diagnosis. The identification of specific signaling pathways that are defective in certain types of renal neoplasms has made possible the design of target-specific therapies that are directed towards the aberrant pathways associated with the defective proteins found in these tumors. This makes the exact classification of these neoplasms and the detection of these aberrant proteins targeted for treatment an absolute requirement for the application of these molecular-based therapeutic interventions. The role that the pathologic assessment plays in the classification of renal tumors becomes more important than ever to take advantage of this and similar new molecular-oriented therapies.

Immunochemotherapy-associated protein patterns in tumour tissue and serum of patients with metastatic renal cell carcinoma

CONTEXT

Systemic treatment of metastatic renal cell carcinoma (mRCC) with targeted therapies became widely accepted; however, there are few patients who greatly benefit from immunochemotherapy (ICT). It is crucial to recognize these patients for individual treatment.

OBJECTIVES

Definition of protein patterns in tissue and serum from mRCC-patients to predict benefit from ICT.

MATERIALS AND METHODS

Twenty-five tissue samples and 59 sera were analysed by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS). Protein peaks of interest were identified by 2D-PAGE and peptide mass fingerprinting. Validation was carried out by Western Blot and ELISA.

RESULTS

Protein patterns associated with therapy response were determined. Caveolin-1 (CAV-1) and plasminogen activator inhibitor 1 (PAI-1) were identified in tissue; serum amyloid A (SAA) and transthyretin (TTR) were found in serum.

CONCLUSION

Individual prediction of therapy benefit and selecting patients for ICT based on molecular biological profiles appear to be feasible in the future.

[Angiogenesis inhibition: review of the activity of sorafenib, sunitinib and bevacizumab]

Renal cell carcinoma accounts for approximately 3% of all human malignancies. The use of cytokines in metastatic stage of disease has been the standard until last decades, presenting partial and short duration responses. Research on angiogenesis in renal carcinoma has brought important advances to understand tumor biology and to allow us development of new antiangiogenic drugs. Sunitinib (SUTENT), sorafenib (NEXAVAR) and bevacizumab (AVASTIN) are actually three molecules accepted to use in metastatic renal cell carcinoma (mRCC), with a good tolerability demonstrated in different studies. Clinical evidence shows sunitinib to be reference standard of care for the first-line treatment of mRCC. The use of bevacizumab in combination with interferon alfa (IFN alfa) can also be considered in this setting. Sorafenib is recommended for second-line treatment in cytokine-refractory patients, sunitinib being also accepted in this situation. Other combination of these molecules and their use as neo-adjuvant and adjuvant therapy is being evaluated and should change in the short term the management of the disease.

Tensin3 is a negative regulator of cell migration and all four Tensin family members are downregulated in human kidney cancer

Background

The Tensin family of intracellular proteins (Tensin1, -2, -3 and -4) are thought to act as links between the extracellular matrix and the cytoskeleton, and thereby mediate signaling for cell shape and motility. Dysregulation of Tensin expression has previously been implicated in human cancer. Here, we have for the first time evaluated the significance of all four Tensins in a study of human renal cell carcinoma (RCC), as well as probed the biological function of Tensin3.

Principal Findings

Expression of Tensin2 and Tensin3 at mRNA and protein levels was largely absent in a panel of diverse human cancer cell lines. Quantitative RT-PCR analysis revealed mRNA expression of all four Tensin genes to be significantly downregulated in human kidney tumors (50–100% reduction versus normal kidney cortex; P<0.001). Furthermore, the mRNA expressions of Tensins mostly correlated positively with each other and negatively with tumor grade, but not tumor size. Immunohistochemical analysis revealed Tensin3 to be present in the cytoplasm of tubular epithelium in normal human kidney sections, whilst expression was weaker or absent in 41% of kidney tumors. A subset of tumor sections showed a preferential plasma membrane expression of Tensin3, which in clear cell RCC patients was correlated with longer survival. Stable expression of Tensin3 in HEK 293 cells markedly inhibited both cell migration and matrix invasion, a function independent of putative phosphatase activity in Tensin3. Conversely, siRNA knockdown of endogenous Tensin3 in human cancer cells significantly increased their migration.

Conclusions

Our findings indicate that the Tensins may represent a novel group of metastasis suppressors in the kidney, the loss of which leads to greater tumor cell motility and consequent metastasis. Moreover, tumorigenesis in the human kidney may be facilitated by a general downregulation of Tensins. Therefore, anti-metastatic therapies may benefit from restoring or preserving Tensin expression in primary tumors.