The impact of FGFR1 and FRS2α expression on sorafenib treatment in metastatic renal cell carcinoma

Blood- and Urine-Based Liquid Biopsy for Early-Stage Cancer Investigation: Taken Clear Renal Cell Carcinoma as a Model

Liquid biopsy is a noninvasive technique that can provide valuable information for disease characterization by using biofluids as a source of biomarkers. Proteins found in biofluids can offer a wealth of information for understanding pathological processes. In this study, we used early-stage clear cell renal cell carcinoma (ccRCC) as a model to explore the proteomic relationships among tissue, plasma, and urine. We analyzed samples of tumor tissue, plasma, and urine from a cohort of 27 ccRCC patients with T1-2 stage and 27 matched healthy controls, using liquid chromatography-mass spectrometry (LC-MS) for proteomic analysis. We integrated the differential proteins found in the three types of samples to explore ccRCC-associated molecular changes. Our results showed that both plasma and urine proteomes could reflect functional changes in tumor tissue. In plasma, cytoskeletal proteins and metabolic enzymes were differentially expressed, while in urine, adhesion molecules and defense proteins showed differential levels. The differential proteins found in plasma and urine both reflect the binding and catalytic activity of tumor tissue. Additionally, proteins only changed in biofluids could reflect body immune response changes, with plasma proteins involved in actin cytoskeleton and oxidative stress, and urine proteins involved in granulocyte adhesion and leukocyte extravasation signaling. Plasma and urine proteins could effectively distinguish RCC from control, with good performances (plasma/urine: 92.6%/92.6% specificity, 96.3%/92.6% sensitivity, and an area under the curve of 0.981/0.97). In conclusion, biofluids could not only reflect functional changes in tumor tissue but also reflect changes in the body's immune response. These findings will benefit the understanding of body biomarkers in tumors and the discovery of potential disease biomarkers.

Therapeutic sequencing in advanced renal cell carcinoma: How to choose considering clinical and biological factors

In the last fifteen years a better understanding of the biological processes promoting tumour growth and progression led to an impressive revolution in metastatic renal cell carcinoma (mRCC) treatment landscape. Angiogenesis plays a critical role in the pathogenesis of RCC. These biological evidences led to targeted therapies interfering with vascular endothelial growth factor and mammalian target of rapamycin pathway. Another big step in the RCC therapeutic landscape was recently made because of the understanding of the interplay between angiogenesis and immune cells. Dual immune checkpoint inhibitors (ICIs) and ICIs plus tyrosine kinase inhibitors (TKI) combinations have been approved considering overall survival benefit compared to targeted therapies as first line treatment. We summarize the activity and the biological rationale of ICIs combinations as mRCC first line therapy. Additionally, we review the clinical and biological criteria useful to guide clinicians in the choice of treatment sequencing focusing on ICIs combinations resistance mechanisms.

Gene Expression-Based Signature Can Predict Sorafenib Response in Kidney Cancer

Sorafenib is a tyrosine kinase inhibitory drug with multiple molecular specificities that is approved for clinical use in second-line treatments of metastatic and advanced renal cell carcinomas (RCCs). However, only 10–40% of RCC patients respond on sorafenib-containing therapies, and personalization of its prescription may help in finding an adequate balance of clinical efficiency, cost-effectiveness, and side effects. We investigated whether expression levels of known molecular targets of sorafenib in RCC can serve as prognostic biomarker of treatment response. We used Illumina microarrays to profile RNA expression in pre-treatment formalin-fixed paraffin-embedded (FFPE) samples of 22 metastatic or advanced RCC cases with known responses on next-line sorafenib monotherapy. Among them, nine patients showed partial response (PR), three patients—stable disease (SD), and 10 patients—progressive disease (PD) according to Response Evaluation Criteria In Solid Tumors (RECIST) criteria. We then classified PR + SD patients as “responders” and PD patients as “poor responders”. We found that gene signature including eight sorafenib target genes was congruent with the drug response characteristics and enabled high-quality separation of the responders and poor responders [area under a receiver operating characteristic curve (AUC) 0.89]. We validated these findings on another set of 13 experimental annotated FFPE RCC samples (for 2 PR, 1 SD, and 10 PD patients) that were profiled by RNA sequencing and observed AUC 0.97 for 8-gene signature as the response classifier. We further validated these results in a series of qRT-PCR experiments on the third experimental set of 12 annotated RCC biosamples (for 4 PR, 3 SD, and 5 PD patients), where 8-gene signature showed AUC 0.83.

New frontiers against sorafenib resistance in renal cell carcinoma: From molecular mechanisms to predictive biomarkers

Renal cell carcinoma (RCC) is a highly vascularized tumor and prone to distant metastasis. Sorafenib is the first targeted multikinase inhibitor and first-line chemical drug approved for RCC therapy. In fact, only a small number of RCC patients benefit significantly from sorafenib treatment, while the growing prevalence of sorafenib resistance has become a major obstacle for drug therapy effectivity of sorafenib. The molecular mechanisms of sorafenib resistance in RCC are not completely understood by now. Herein, we comprehensively summarize the underlying mechanisms of sorafenib resistance and molecular biomarkers for predicting sorafenib responsiveness. Moreover, we outline strategies suitable for overcoming sorafenib resistance and prospect potential approaches for identifying biomarkers associated with sorafenib resistance in RCC, which contributes to guide individualized and precision drug therapy.

Immunochemical expression of fibroblast growth factor and its receptors in primary tumor cells of renal cell carcinoma

BACKGROUND

There is the evidence of the role of the fibroblast growth factor and its receptors (FGF/FGFR) signaling pathway in tumorogenesis of renal cell carcinoma (RCC). We conducted a study aimed at evaluating of FGF2, FGFR1, and FGFR2 expression in primary tumor cells and assessing of these molecules expression levels effect on the characteristics of the tumor process and prognosis of patients with RCC.

METHODS

Expression of FGF2, FGFR1, and FGFR2 was investigated in 65 primary RCC specimens by immuhistochemical staining using the appropriate antibodies. Expression levels were evaluated by the semi-quantitative method. A search for correlations of expression levels of investigated growth factors and receptors with RCC features and patients outcomes was performed.

RESULTS

Cytoplasm and membrane expression of FGF2, FGFR1, and FGFR2 was found in the primary tumor cells of RCC patients. FGF2 staining was detected in 60.0% of cases (44.2 ± 5.4 HS). It was noted higher frequency and intensity of FGFR2 expression (66.2%; 46.6 ± 6.3 HS) comparing with FGFR1 (32.3%; 7.5 ± 2.2 HS). The correlation was revealed between the investigated markers overexpression and Fuhrman grade G3-4, as well as features of advanced RCC (paranephric fat tumor invasion, venous wall tumor invasion, adrenal and liver metastases). FGFR2 overexpression showed negative influence on cancer-specific survival in univariate analysis, however, lost its predictive value in multivariable analysis.

CONCLUSION

Expression of FGF2 and its receptors was found on the surface and in the cytoplasm of RCC primary tumor cells and needs following investigations.

Expression of growth factors and their receptors in the primary renal cell carcinoma: new data and review

Introduction

The aim of our study was to investigate expression levels and the prognostic value of multiple growth factors and their receptors in the primary tumor cells of renal cell carcinoma (RCC).

Material and methods

Expression of vascular endothelial growth factor (VEGF)A, fibroblast growth factor (FGF)2, vascular endothelial growth factor receptor (VEGFR)1, VEGFR2, FGFR1, FGFR2, platelet-derived growth factor receptor (PDGFR)α, and PDGFRβ was investigated in 65 primary RCC specimens by immuhistochemical staining using the appropriate antibodies. Expression levels were evaluated by the semi-quantitative method. A search for correlations of expression levels of investigated growth factors and receptors with RCC features and patients outcomes was performed.

Results

Expression of all growth factors and their receptors was detected both on the surface and in the cytoplasm of the primary tumor cells in RCC patients. The expression of all analyzed factors was interconnected. FGFR2 expression correlated with the largest number of other growth factors and receptors. A strong correlation was revealed between high expression of the studied markers, high Fuhrman grade, and advanced RCC stages. In a univariate analysis overexpression of VEGFR2 (p <0.0001) and FGFR2 (p = 0.014) had negative influence on cancer-specific survival.

Conclusions

Expression of growth factors and tyrosine kinase receptors in the primary tumor cells is strongly interconnected and associated with unfavorable features of RCC.

FGFR1 is associated with c-MYC and proangiogenic molecules in metastatic renal cell carcinoma under anti-angiogenic therapy

AIMS

This study aimed to investigate the clinicopathological significance of FGFR1 and c-MYC expression, particularly in relation to angiogenesis in clear cell renal cell carcinoma (CCRCC).

METHODS AND RESULTS

Immunohistochemistry and fluorescence in-situ hybridisation were conducted with tissue microarrays from 91 metastatic CCRCC patients who received VEGF receptor tyrosine kinase inhibitors (VEGFR-TKIs). The expression of angiogenic molecules, FGFR1 and c-MYC, and tumoral vascular density (TVD) and mRNA expression and TVD of 533 CCRCCs in The Cancer Genome Atlas (TCGA) were analysed. FGFR1, pFGFR1 and c-MYC expression was observed in 29.1, 74.4 and 30.8% of tumours, respectively. FGFR1^high was an independent worse prognostic factor for overall (HR = 1.871, P = 0.032) and progression-free (HR = 1.976, P = 0.016) survival. FGFR1^high was significantly related to VEGFR-TKI responsiveness (P = 0.011). The presence of FGFR1^high /c-MYC^high showed a positive correlation with proangiogenic markers, including VEGF (P = 0.018) and HIF-1α (P < 0.0001). FGFR1^high /c-MYC^high tumours showed higher TVDs together with higher VEGFR2 and PDGFR-β expression (both P < 0.0001). FGFR1 and c-MYC expression was also positively correlated with the expression of hypoxia-related and proangiogenic-related genes in the TCGA data.

CONCLUSIONS

FGFR1 and c-MYC may be involved in tumour angiogenesis and FGFR1 may represent a promising therapeutic target in metastatic CCRCC.

Phosphoinositides in the kidney

Phosphoinositides (PIs) play pivotal roles in the regulation of many biological processes. The quality and quantity of PIs is regulated in time and space by the activity of PI kinases and PI phosphatases. The number of PI-metabolizing enzymes exceeds the number of PIs with, in many cases, more than one enzyme controlling the same biochemical step. This would suggest that the PI system has an intrinsic ability to buffer and compensate for the absence of a specific enzymatic activity. However, there are several examples of severe inherited human diseases caused by mutations in one of the PI enzymes, although other enzymes with the same activity are fully functional. The kidney depends strictly on PIs for physiological processes, such as cell polarization, filtration, solute reabsorption, and signal transduction. Indeed, alteration of the PI system in the kidney very often results in pathological conditions, both inherited and acquired. Most of the knowledge of the roles that PIs play in the kidney comes from the study of KO animal models for genes encoding PI enzymes and from the study of human genetic diseases, such as Lowe syndrome/Dent disease 2 and Joubert syndrome, caused by mutations in the genes encoding the PI phosphatases, OCRL and INPP5E, respectively.

Targeting of tumor growth and angiogenesis underlies the enhanced antitumor activity of lenvatinib in combination with everolimus

The combination of lenvatinib, a multiple receptor tyrosine kinase inhibitor, plus everolimus, a mammalian target of rapamycin (mTOR) inhibitor, significantly improved clinical outcomes versus everolimus monotherapy in a phase II clinical study of metastatic renal cell carcinoma (RCC). We investigated potential mechanisms underlying the antitumor activity of the combination treatment in preclinical RCC models. Lenvatinib plus everolimus showed greater antitumor activity than either monotherapy in three human RCC xenograft mouse models (A‐498, Caki‐1, and Caki‐2). In particular, the combination led to tumor regression in the A‐498 and Caki‐1 models. In the A‐498 model, everolimus showed antiproliferative activity, whereas lenvatinib showed anti‐angiogenic effects. The anti‐angiogenic activity was potentiated by the lenvatinib plus everolimus combination in Caki‐1 xenografts, in which fibroblast growth factor (FGF)‐driven angiogenesis may contribute to tumor growth. The combination showed mostly additive activity in vascular endothelial growth factor (VEGF)‐activated, and synergistic activity against FGF‐activated endothelial cells, in cell proliferation and tube formation assays, as well as strongly suppressed mTOR‐S6K‐S6 signaling. Enhanced antitumor activities of the combination versus each monotherapy were also observed in mice bearing human pancreatic KP‐1 xenografts overexpressing VEGF or FGF. Our results indicated that simultaneous targeting of tumor cell growth and angiogenesis by lenvatinib plus everolimus resulted in enhanced antitumor activity. The enhanced inhibition of both VEGF and FGF signaling pathways by the combination underlies its superior anti‐angiogenic activity in human RCC xenograft models.

Strategies to overcome therapeutic resistance in renal cell carcinoma

BACKGROUND

Renal cell cancer (RCC) is a prevalent and lethal disease. At time of diagnosis, most patients present with localized disease. For these patients, the standard of care includes nephrectomy with close monitoring thereafter. While many patients will be cured, 5-year recurrence rates range from 30% to 60%. Furthermore, nearly one-third of patients present with metastatic disease at time of diagnosis. Metastatic disease is rarely curable and typically lethal. Cytotoxic chemotherapy and radiation alone are incapable of controlling the disease. Extensive effort was expended in the development of cytokine therapies but response rates remain low. Newer agents targeting angiogenesis and mTOR signaling emerged in the 2000s and revolutionized patient care. While these agents improve progression free survival, the development of resistance is nearly universal. A new era of immunotherapy is now emerging, led by the checkpoint inhibitors. However, therapeutic resistance remains a complex issue that is likely to persist.

METHODS AND PURPOSE

In this review, we systematically evaluate preclinical research and clinical trials that address resistance to the primary RCC therapies, including anti-angiogenesis agents, mTOR inhibitors, and immunotherapies. As clear cell RCC is the most common adult kidney cancer and has been the focus of most studies, it will be the focus of this review.

FGFs: crucial factors that regulate tumour initiation and progression

Fibroblast growth factors (FGFs) are crucial signalling molecules involved in normal cell growth, differentiation and proliferation. Over the past few decades, a large body of research has illustrated effects of individual FGFs on tumour initiation and progression. Tumour development is commonly accompanied with generation of new blood and lymph vessels, which support enhanced cell proliferation. Moreover, acquisition of tumour cells of the epithelial-mesenchymal transition (EMT) phenotype, enhances tumour cell migration and invasion potentials, crucial steps in tumour metastasis. This review summarizes recent findings concerning roles of FGFs in angiogenesis, lymphangiogenesis and EMT.

KRT6 interacting with notch1 contributes to progression of renal cell carcinoma, and aliskiren inhibits renal carcinoma cell lines proliferation in vitro

Notch signaling is a conserved and widely expressed signaling pathway, which mediates various physiological processes including tumorigenesis. This study aims to explore the potential role and mechanism of notch1 interacting with KRT6B in the progression of RCC. The results indicated that the mRNA and protein expression of notch1 and KRT6 were significantly increased in tumor tissues, and highly positive correlation existed between notch1 and KRT6. Moreover, the patients with high notch1 expression had a significantly poorer prognosis than those of low expression patients. In vitro, KRT6 loss-of-function could inhibit the expression of notch1 and induce renal carcinoma cell death. Eventually, we found that renin inhibitor, aliskiren, could inhibit cell proliferation and decrease the expression of notch1 and KRT6 as well as regulate apoptosis-related protein expression in 786-O and ACHN renal carcinoma cell lines. These results suggested that the upregulation of notch1 and KRT6B might be involved in the development, progression and prognosis of human RCC, and aliskiren could suppress renal carcinoma cell proliferation, at least partially, through downregulation the expression of notch1 and KRT6.