The relevance of testing the efficacy of anti-angiogenesis treatments on cells derived from primary tumors: a new method for the personalized treatment of renal cell carcinoma.

Renaud Grépin,Florence Pedeutour,Jean Amiel,Lauris Gastaud,Alexandre Marsaud,Damien Ambrosetti,Gilles Pagès

doi:10.1371/journal.pone.0089449

Abstract

Despite the numerous available drugs, the most appropriate treatments for patients affected by common or rare renal cell carcinomas (RCC), like those associated with the Xp11.2 translocation/transcription factor for immunoglobulin heavy-chain enhancer 3 (TFE3) gene fusion (TFE3 RCC), are not clearly defined. We aimed to make a parallel between the sensitivity to targeted therapies on living patients and on cells derived from the initial tumor. Three patients diagnosed with a metastatic RCC (one clear cell RCC [ccRCC], two TFE3 RCC) were treated with anti-angiogenesis drugs. The concentrations of the different drugs giving 50% inhibition of cell proliferation (IC50) were determined with the Thiazolyl Blue Tetrazolium Bromide (MTT) assay on cells from the primary tumors and a reference sensitive RCC cell line (786-O). We considered the cells to be sensitive if the IC50 was lower or equal to that in 786-O cells, and insensitive if the IC50 was higher to that in 786-O cells (IC 50 of 6±1 µM for sunitinib, 10±1 µM for everolimus and 6±1 µM for sorafenib). Based on this standard, the response in patients and in cells was equivalent. The efficacy of anti-angiogenesis therapies was also tested in cells obtained from five patients with non-metastatic ccRCC, and untreated as recommended by clinical practice in order to determine the best treatment in case of progression toward a metastatic grade. In vitro experiments may represent a method for evaluating the best first-line treatment for personalized management of ccRCC during the period following surgery.

Highlights

Even though ccRCC represent the most common type of kidney cancer, approximately 20% of renal cell carcinomas (RCC) are not ccRCC [1]
Representative examples of rare RCC include those associated with Xp11.2 translocation which leads to the rearrangement of the transcription factor E3 (TFE3) gene [2]
Expression of the receptors targeted by sunitinib and sorafenib on tumor cells Considering that the effects of anti-angiogenesis treatments on endothelial cells are equivalent for any patient, the different responses to the drugs may be attributed to the genetic variability of tumor cells expressing the target receptors and/or overactivating the mTOR pathway

Summary

Introduction

Even though ccRCC represent the most common type of kidney cancer, approximately 20% of RCC are not ccRCC [1]. Representative examples of rare RCC include those associated with Xp11.2 translocation which leads to the rearrangement of the transcription factor E3 (TFE3) gene [2]. TFE3 fuses with any of the following gene partners; papillary renal cell carcinomas (PRCC) [3], non-POU domain containing octamer binding (NONO), splicing factor proline/glutamine rich (PFS) [4], renal cell carcinoma chromosome 17 (RCC 17) [5], clathrin heavy chain (CLTC) [6] and an unknown gene present on chromosome 19 [7]. TFE3 RCC presents both papillary/alveolar architecture and tumor cells with a clear cytoplasm. Tumors characterized with chromosomal translocations involving the TFE3 gene show strong nuclear immuno-reactivity of the TFE3 protein. Over-expression of the fusion protein induces abnormal cell proliferation and motility as a result of its binding to the E2F3 transcription factor [8], impaired binding of the checkpoint protein MAD2B [9], deregulation of cell-cycle mediators [10,11] and expression of the c-MET tyrosine kinase receptor [12]

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Conclusion