Association of AXL and PD-L1 expression with clinical outcomes in patients with advanced renal cell carcinoma treated with PD-1 blockade

PURPOSE

A minority of patients currently respond to single agent immune checkpoint blockade (ICB) and strategies to increase response rates are urgently needed. AXL is receptor tyrosine kinase commonly associated with drug-resistance and poor prognosis in many cancer types including in clear-cell renal cell carcinoma (ccRCC). Recent experimental cues in breast, pancreatic and lung cancer models have linked AXL with immune suppression and resistance to antitumor immunity. However, its role in intrinsic and acquired resistance to ICB remains largely unexplored.

EXPERIMENTAL DESIGN

In this study, tumoral expression of AXL was examined in ccRCC specimens from 316 metastatic patients receiving PD-1 inhibitor, nivolumab, in the GETUG AFU 26 NIVOREN trial after failure of anti-angiogenic therapy. We assessed associations between AXL and patient outcomes following PD-1 blockade, as well as the relationship with various markers including PD-L1, VEGFA, the immune markers CD3, CD8, CD163, CD20, and the mutational status of the tumor suppressor gene VHL Results: Our results show that high AXL expression levels in tumor cells is associated with lower response rates and a trend to shorter progression-free survival following anti-PD-1 treatment. AXL expression was strongly associated with tumor PD-L1 expression, especially in tumors with VHL inactivation. Moreover, patients with tumors displaying concomitant PD-L1 expression and high AXL expression had the worst overall survival.

CONCLUSIONS

Our findings propose AXL as candidate factor of resistance to PD-1 blockade, and provide compelling support for screening both AXL and PD-L1 expression in the management of advanced ccRCC.

Identification of a new aggressive axis driven by ciliogenesis and absence of VDAC1-ΔC in clear cell Renal Cell Carcinoma patients

Rationale: Renal cell carcinoma (RCC) accounts for about 2% of all adult cancers, and clear cell RCC (ccRCC) is the most common RCC histologic subtype. A hallmark of ccRCC is the loss of the primary cilium, a cellular antenna that senses a wide variety of signals. Loss of this key organelle in ccRCC is associated with the loss of the von Hippel-Lindau protein (VHL). However, not all mechanisms of ciliopathy have been clearly elucidated.

Methods: By using RCC4 renal cancer cells and patient samples, we examined the regulation of ciliogenesis via the presence or absence of the hypoxic form of the voltage-dependent anion channel (VDAC1-ΔC) and its impact on tumor aggressiveness. Three independent cohorts were analyzed. Cohort A was from PREDIR and included 12 patients with hereditary pVHL mutations and 22 sporadic patients presenting tumors with wild-type pVHL or mutated pVHL; Cohort B included tissue samples from 43 patients with non-metastatic ccRCC who had undergone surgery; and Cohort C was composed of 375 non-metastatic ccRCC tumor samples from The Cancer Genome Atlas (TCGA) and was used for validation. The presence of VDAC1-ΔC and legumain was determined by immunoblot. Transcriptional regulation of IFT20/GLI1 expression was evaluated by qPCR. Ciliogenesis was detected using both mouse anti-acetylated α-tubulin and rabbit polyclonal ARL13B antibodies for immunofluorescence.

Results: Our study defines, for the first time, a group of ccRCC patients in which the hypoxia-cleaved form of VDAC1 (VDAC1-ΔC) induces resorption of the primary cilium in a Hypoxia-Inducible Factor-1 (HIF-1)-dependent manner. An additional novel group, in which the primary cilium is re-expressed or maintained, lacked VDAC1-ΔC yet maintained glycolysis, a signature of epithelial-mesenchymal transition (EMT) and more aggressive tumor progression, but was independent to VHL. Moreover, these patients were less sensitive to sunitinib, the first-line treatment for ccRCC, but were potentially suitable for immunotherapy, as indicated by the immunophenoscore and the presence of PDL1 expression.

Conclusion: This study provides a new way to classify ccRCC patients and proposes potential therapeutic targets linked to metabolism and immunotherapy.

Identification and validation of TGFBI as a promising prognosis marker of clear cell renal cell carcinoma

OBJECTIVE

To identify prognostic biomarkers in clear cell renal cell carcinoma (ccRCC) using a proteomic approach.

MATERIAL AND METHODS

We performed a comparative proteomic profiling of ccRCC and normal renal tissues from 9 different human specimens. We assessed differential protein expression by iTRAQ (isobaric tagging reagent for absolute quantify) labeling with regard to tumor aggressiveness according to the stage, size, grade, and necrosis (SSIGN) score and confirmed our results using Western blot (9 patients) and immunohistochemistry (135 patients) analysis.

RESULTS

After proteomic analysis, 928 constitutive proteins were identified. Among these proteins, 346 had a modified expression in tumor compared with that of normal tissue. Pathway and integrated analyses indicated the presence of an up-regulation of the pentose phosphate pathway in aggressive tumors. In total, 14 proteins were excreted and could potentially become biomarkers. Overexpression of transforming growth factor, beta-induced (TGFBI) in ccRCC was confirmed using Western blot and immunohistochemistry analysis. A significant association was found between the presence of TGFBI expression with tumor category T3-4 (P<0.0001), Fuhrman grades III and IV (P<0.0001), tumor size>4cm (P<0.0001), presence of tumor necrosis (P<0.0001), nodal involvement (n = 0.009), metastasis (P = 0.012), SSIGN score≥5 (P<0.0001), cancer progression (P<0.0001), and cancer-specific death (P<0.0001). Cancer-specific survival was significantly better for patients with no cytoplasmic TGFBI expression (1-, 3-, 5-y cancer-specific survival of 94.7%, 87.8%, and 73.4% vs. 92.9%, 71.2%, and 49.8%, respectively; P<0.0001).

CONCLUSION

We identified 346 proteins involved in renal carcinogenesis and confirmed the presence of a metabolic shift in aggressive tumors. TGFBI was overexpressed in tumors with high SSIGN scores and was significantly associated with oncologic outcomes.

VEGFR1 single nucleotide polymorphisms associated with outcome in patients with metastatic renal cell carcinoma treated with sunitinib - a multicentric retrospective analysis

BACKGROUND

There are no validated markers that predict outcome in metastatic renal cell cancer (mRCC) patients treated with sunitinib. Recently, single nucleotide polymorphism (SNP) rs9582036 in VEGFR1 has been proposed as a predictor of progression-free survival (PFS) and overall survival (OS) to bevacizumab in patients with pancreatic cancer and rs7993418 in VEGFR1 as predictor for PFS in mRCC-patients treated with bevacizumab. Here, we aim to study the impact of these SNPs in mRCC patients treated with sunitinib.

METHODS

We included patients with mRCC treated in 15 institutions in France and Belgium. Patients received sunitinib as first-line targeted therapy. We assessed response, time-to-tumor progression (TTP), OS, and clinical and biochemical parameters associated with outcome. We genotyped rs9582036 and rs7993418 as well as three other surrounding SNPs in VEGFR1: rs9554320, rs9554316 and rs9513070. Association between SNPs and treatment outcome were studied by univariate analysis and by multivariate Cox regression using relevant clinical factors associated with TTP and OS as covariates.

FINDINGS

Ninety-one patients were included. We found that mRCC patients with the CC-variant in rs9582036 in VEGFR1 have a poorer response rate (RR) (0% vs. 46%, p = 0.028), a poorer PFS (10 vs. 18 months, p = 0.033 on univariate and 0.06 on multivariate analysis) and a poorer OS (14 vs. 31 months, p = 0.019 on univariate and 0.008 on multivariate analysis) compared to patients with the AC- and AA-genotypes. mRCC patients with the AA-variant in rs9554320 in VEGFR1 have a poorer PFS (12 vs. 21 months, p = 0.0066 on univariate and 0.005 on multivariate analysis) and a poorer OS (22 vs. 34 months, p = 0.019 on univariate and 0.067 on multivariate analysis) compared to patients with the AC- and CC-genotypes. Interpretation. mRCC patients with the CC-genotype in VEGFR1 SNP rs9582036 have a poorer response rate, PFS and OS when treated with sunitinib. These findings are in agreement with the association of rs9582036 and outcome observed in bevacizumab treated pancreatic cancer patients. Prospective validation of this SNP is warranted.