Standard versus fractionated high-dose cisplatin plus radiation for locally advanced head and neck cancer: Results of the CisFRad (GORTEC 2015-02) randomized phase II trial.

BACKGROUND: Chemoradiotherapy with high-dose cisplatin (HD-Cis: 100 mg/m2 q3w for three cycles) is the standard of care (SOC) in locally advanced head and neck squamous cell carcinoma (LA-HNSCC). Cumulative delivered dose of cisplatin is prognostic of survival, even beyond 200 mg/m2 but high toxicity compromises its delivery. AIM: Cisplatin fractionation may allow, by decreasing the peak serum concentration, to decrease toxicity. To date, no direct comparison was done of HD-Cis versus fractionated high dose cisplatin (FHD-Cis). METHODS: This is a multi-institutional randomized phase II trial, stratified on postoperative or definitive chemoradiotherapy, comparing HD-Cis to FHD-Cis (25 mg/m2/d d1-4 q3w for 3 cycles) in patients with LA-HNSCC. The primary endpoint was the cumulative delivered cisplatin dose. RESULTS: Between December 2015 and April 2018, 124 patients were randomized. Median cisplatin cumulative delivered dose was 291 mg/m2 (IQR: 251;298) in the FHD-Cis arm and 274 mg/m2 (IQR: 198;295) in the HD-Cis arm (P = 0.054). The proportion of patients receiving a third cycle of cisplatin was higher, with a lower proportion of grade 3-4 acute AEs in the FHD-Cis arm compared to the HD-Cis arm: 81 % vs. 64 % (P = 0.04) and 10 % vs. 17 % (P = 0.002), respectively. With a median follow-up of 48 months (IQR: 41;55), locoregional failure rate, PFS and OS were similar between the two arms. CONCLUSION: Although the primary endpoint was not met, FHD-Cis allowed more cycles of cisplatin to be delivered with lower toxicity, when compared to SOC. FHD-Cis concurrently with RT is a treatment option which deserves further consideration.

GW501516-Mediated Targeting of Tetraspanin 15 Regulates ADAM10-Dependent N-Cadherin Cleavage in Invasive Bladder Cancer Cells.

Bladder cancer aggressiveness is correlated with abnormal N-cadherin transmembrane glycoprotein expression. This protein is cleaved by the metalloprotease ADAM10 and the γ-secretase complex releasing a pro-angiogenic N-terminal fragment (NTF) and a proliferation-activating soluble C-terminal fragment (CTF2). Tetraspanin 15 (Tspan15) is identified as an ADAM10-interacting protein to induce selective N-cadherin cleavage. We first demonstrated, in invasive T24 bladder cancer cells, that N-cadherin was cleaved by ADAM10 generating NTF in the extracellular environment and leaving a membrane-anchored CTF1 fragment and that Tspan15 is required for ADAM10 to induce the selective N-cadherin cleavage. Targeting N-cadherin function in cancer is relevant to preventing tumor progression and metastases. For antitumor molecules to inhibit N-cadherin function, they should be complete and not cleaved. We first showed that the GW501516, an agonist of the nuclear receptor PPARß/δ, decreased Tspan15 and prevented N-cadherin cleavage thus decreasing NTF. Interestingly, the drug did not modify ADAM10 expression, which was important because it could limit side effects since ADAM10 cleaves numerous substrates. By targeting Tspan15 to block ADAM10 activity on N-cadherin, GW501516 could prevent NTF pro-tumoral effects and be a promising molecule to treat bladder cancer. More interestingly, it could optimize the effects of the N-cadherin antagonists those such as ADH-1 that target the N-cadherin ectodomain.

Molecular and nanoscale evaluation of N-cadherin expression in invasive bladder cancer cells under control conditions or GW501516 exposure.

N-cadherin is a transmembrane glycoprotein expressed by mesenchymal origin cells and is located at the adherens junctions. It regulates also cell motility and contributes to cell signaling. In previous studies, we identified that its anomalous expression in bladder carcinoma was a tumor progression marker. A pharmacological approach to inhibit N-cadherin expression or to block its function could be relevant to prevent disease progression and metastasis development. The morphological exploration of T24 invasive bladder cancer cells by atomic force microscopy (AFM) revealed a spindle-like shape with fibrous structures. By engaging force spectroscopy with AFM tip functionalized with anti-E or anti-N-cadherin antibodies, results showed that T24 cells expressed only N-cadherin as also demonstrated by Western blotting and confocal microscopy. For the first time, we demonstrated by RTqPCR and Western blotting analyses that the peroxisome proliferator-activated receptor ß/δ (PPARß/δ) agonist GW501516 significantly decreased N-cadherin expression in T24 cells. Moreover, high non-cytotoxic doses of GW501516 inhibited confluent T24 cell wound healing closure. By using AFM, a more sensitive nanoanalytical method, we showed that the treatment modified the cellular morphology and diminished N-cadherin cell surface coverage through the decreasing of these adhesion molecule-mediated interaction forces. We observed a greater decrease of N-cadherin upon GW501516 exposure with AFM than that detected with molecular biology techniques. AFM was a complementary tool to biochemical techniques to perform measurements on living cells at the nanometer resolution level. Taken together, our data suggest that GW501516 could be an interesting therapeutic strategy to avoid bladder cancer cell spreading through N-cadherin decrease.

Approach to oligometastatic disease in head and neck cancer, on behalf of the GORTEC.

Median survival for recurrent/metastatic head and neck squamous cell cancer (HNSCC) patients is about 10 months after first-line best systemic treatment. We aimed to assess current approaches of oligometastatic HNSCC patients by the analysis of current concept and published data (1995-2017) in this population. Five-year survival rates are over 20% in selected patients who undergo metastasis-directed therapy by either surgery or stereotactic irradiation. Human papillomavirus(+) HNSCC patients have more disseminated metastases but respond more favorably and also benefit from ablative treatments. Treatments of oligometastases are expanding rapidly. Unmet needs include revised imaging follow-up strategies to detect metastases earlier, identification of predictive noninvasive biomarkers for treatment guidance, assessment and corrections of biases in current studies and randomized clinical trials.

Apoptotic effect of the selective PPARß/δ agonist GW501516 in invasive bladder cancer cells.

GW501516 is a selective and high-affinity synthetic agonist of peroxisome proliferator-activated receptor ß/δ (PPARß/δ). This molecule promoted the inhibition of proliferation and apoptosis in few cancer cell lines, but its anticancer action has never been investigated in bladder tumor cells. Thus, this study was undertaken to determine whether GW501516 had antiproliferative and/or apoptotic effects on RT4 and T24 urothelial cancer cells and to explore the molecular mechanisms involved. Our results indicated that, in RT4 cells (derived from a low-grade papillary tumor), GW501516 did not induce cell death. On the other hand, in T24 cells (derived from an undifferentiated high-grade carcinoma), this PPARß/δ agonist induced cytotoxic effects including cell morphological changes, a decrease of cell viability, a G2/M cell cycle arrest, and the cell death as evidenced by the increase of the sub-G1 cell population. Furthermore, GW501516 triggered T24 cell apoptosis in a caspase-dependent manner including both extrinsic and intrinsic apoptotic pathways through Bid cleavage. In addition, the drug led to an increase of the Bax/Bcl-2 ratio, a mitochondrial dysfunction associated with the dissipation of ΔΨm, and the release of cytochrome c from the mitochondria to the cytosol. GW501516 induced also ROS generation which was not responsible for T24 cell death since NAC did not rescue cells upon PPARß/δ agonist exposure. For the first time, our data highlight the capacity of GW501516 to induce apoptosis in invasive bladder cancer cells. This molecule could be relevant as a therapeutic drug for high-grade urothelial cancers.