Benjamin Lallemant

Pregnane × Receptor (PXR) expression in colorectal cancer cells restricts irinotecan chemosensitivity through enhanced SN-38 glucuronidation

BackgroundClinical efficacy of chemotherapy in colorectal cancer is subjected to broad inter-individual variations leading to the inability to predict outcome and toxicity. The topoisomerase I inhibitor irinotecan (CPT-11) is worldwide approved for the treatment of metastatic colorectal cancer and undergoes extensive peripheral and tumoral metabolism. PXR is a xenoreceptor activated by many drugs and environmental compounds regulating the expression of drug metabolism and transport genes in detoxification organs such as liver and gastrointestinal tract. Considering the metabolic pathway of irinotecan and the tissue distribution of Pregnane × Receptor (PXR), we hypothesized that PXR could play a key role in colon cancer cell response to irinotecan.ResultsPXR mRNA expression was quantified by RT-quantitative PCR in a panel of 14 colon tumor samples and their matched normal tissues. PXR expression was modulated in human colorectal cancer cells LS174T, SW480 and SW620 by transfection and siRNA strategies. Cellular response to irinotecan and its active metabolic SN38 was assessed by cell viability assays, HPLC metabolic profiles and mRNA quantification of PXR target genes. We showed that PXR was strongly expressed in colon tumor samples and displayed a great variability of expression. Expression of hPXR in human colorectal cancer cells led to a marked chemoresistance to the active metabolite SN38 correlated with PXR expression level. Metabolic profiles of SN38 showed a strong enhancement of SN38 glucuronidation to the inactive SN38G metabolite in PXR-expressing cells, correlated with an increase of UDPglucuronosyl transferases UGT1A1, UGT1A9 and UGT1A10 mRNAs. Inhibition of PXR expression by lentivirus-mediated shRNA, led to SN38 chemoresistance reversion concomitantly to a decrease of UGT1A1 expression and SN38 glucuronidation. Similarly, PXR mRNA expression levels correlated to UGT1A subfamily expression in human colon tumor biopsies.ConclusionOur results demonstrate that tumoral metabolism of SN38 is affected by PXR and point to potential therapeutic significance of PXR quantification in the prediction of irinotecan response. Furthermore, our observations are pharmacologically relevant since many patients suffering from cancer diseases are often exposed to co-medications, food additives or herbal supplements able to activate PXR. A substantial part of the variability observed among patients might be caused by such interactions

Initial Multi-institutional Experience with Transoral Robotic Surgery

Objective To assess the initial experience for transoral robotic surgery (TORS), as observed in the French TORS group. Study Design A multi-institutional prospective cohort study. Setting Seven tertiary referral centers. Subjects and Methods One hundred thirty consecutive patients who were scheduled for a TORS between October 2008 and March 2011 were included. The operative times, conversion rates, morbidity, and alternatives were described. The serious adverse effects encountered were analyzed, and recommendations for avoiding them are specified. Results Most of the patients (65%) had a laryngeal (supraglottic) and/or hypopharyngeal resection. Thirty-nine of the 130 patients receiving TORS would have had a transoral laser resection as their alternative surgery. The tumor exposure was suboptimal in 26% of the cases. Six of the 130 patients needed conversion to an open approach. There were 15 postoperative hemorrhages and 2 deaths due to posthemorrhage complications in patients with significant comorbidities at 9 and 18 days after the surgery. The median setup and procedure times were 52 ± 46 and 90 ± 92 minutes, respectively. The learning curve was characterized by better selection and management of potential patients. Conclusion The visualization offered by the robotic assistance allowed transoral resections of tumors that were difficult to resect or unresectable by laser surgery. Self-assessment of surgical exposure and a decrease in the need to convert to an open procedure over time suggested improvement in TORS-related surgical skills. Nevertheless, strict patient selection is essential. Even with a minimally invasive approach, some patients will need a tracheostomy for safety reasons.

Clinical relevance of nine transcriptional molecular markers for the diagnosis of head and neck squamous cell carcinoma in tissue and saliva rinse

BackgroundAnalysis of 23 published transcriptome studies allowed us to identify nine genes displaying frequent alterations in HNSCC (FN1, MMP1, PLAU, SPARC, IL1RN, KRT4, KRT13, MAL, and TGM3). We aimed to independently confirm these dysregulations and to identify potential relationships with clinical data for diagnostic, staging and prognostic purposes either at the tissue level or in saliva rinse.MethodsFor a period of two years, we systematically collected tumor tissue, normal matched mucosa and saliva of patients diagnosed with primary untreated HNSCC. Expression levels of the nine genes of interest were measured by RT-qPCR in tumor and healthy matched mucosa from 46 patients. MMP1 expression level was measured by RT-qPCR in the salivary rinse of 51 HNSCC patients and 18 control cases.ResultsDysregulation of the nine genes was confirmed by the Wilcoxon test. IL1RN, MAL and MMP1 were the most efficient diagnostic markers of HNSCC, with ROC AUC > 0.95 and both sensitivity and specificity above 91%. No clinically relevant correlation was found between gene expression level in tumor and T stage, N stage, tumor grade, global survival or disease-free survival. Our preliminary results suggests that with 100% specificity, MMP1 detection in saliva rinse is potentially useful for non invasive diagnosis of HNSCC of the oral cavity or oropharynx, but technical improvement is needed since sensitivity was only 20%.ConclusionIL1RN, MAL and MMP1 are prospective tumor diagnostic markers for HNSCC. MMP1 overexpression is the most promising marker, and its detection could help identify tumor cells in tissue or saliva.

Reference gene selection for head and neck squamous cell carcinoma gene expression studies

BackgroundIt is no longer adequate to choose reference genes blindly. We present the first study that defines the suitability of 12 reference genes commonly used in cancer studies (ACT, ALAS, B2M, GAPDH, HMBS, HPRT, KALPHA, RPS18, RPL27, RPS29, SHAD and TBP) for the normalization of quantitative expression data in the field of head and neck squamous cell carcinoma (HNSCC).ResultsRaw expression levels were measured by RT-qPCR in HNSCC and normal matched mucosa of 46 patients. We analyzed the expression stability using geNorm and NormFinder and compared the expression levels between subgroups. In HNSCC and/or normal mucosa, the four best normalization genes were ALAS, GAPDH, RPS18 and SHAD and the most stable combination of two genes was GAPDH-SHAD. We recommend using KALPHA-TBP for the study of T1-T2 tumors, RPL27-SHAD for T3-T4 tumors, KALPHA-SHAD for N0 tumors, and ALAS-TBP for N+ tumors. ACT, B2M, GAPDH, HMBS, HPRT, KALPHA, RPS18, RPS29, SHAD and TBP were slightly misregulated (<1.7-fold) between tumor and normal mucosa but can be used for normalization, depending on the resolution required for the assay.ConclusionIn the field of HNSCC, this study will guide researchers in selecting the most appropriate reference genes from among 12 potentially suitable reference genes, depending on the specific setting of their experiments.

Randomized phase III trial comparing induction chemotherapy followed by radiotherapy to concomitant chemoradiotherapy for laryngeal preservation in T3M0 pyriform sinus carcinoma.

Conclusions. Conventional radiotherapy with concurrent cisplatin is significantly superior to induction cisplatin fluorouracil chemotherapy followed by radiotherapy in terms of laryngeal preservation in patients with T3 hypopharyngeal carcinoma. Despite a high rate of laryngeal preservation no survival benefit was recorded in this selected population. Objectives. To compare conventional radiotherapy with concurrent cisplatin to induction chemotherapy with cisplatin fluorouracil followed by conventional radiotherapy. The primary end point was the preservation of the larynx. The secondary end points included toxicity, causes of death, and survival rates. Patients and methods. Seventy-one adult patients with previously untreated resectable T3 pyriform sinus squamous cell carcinoma were enrolled in the multicenter prospective randomized phase III trial. They were evaluated for organ preservation, survival rates, and toxic reactions. Results. The rates of laryngeal preservation at 2 years were 68% for the induction chemotherapy (IC) group and 92% for the chemoradiotherapy (CR) group (p = 0.016). At 2 years, the event-free survival rates were 36% and 41% for the IC group and CR group, respectively.

High-resolution melting analysis of sequence variations in the cytidine deaminase gene (CDA) in patients with cancer treated with gemcitabine.

Gemcitabine (2′,2′-difluorodeoxycytidine) is a major antimetabolite cytotoxic drug with a wide spectrum of activity against solid tumors. Hepatic elimination of gemcitabine depends on a catabolic pathway through a deamination step driven by the enzyme cytidine deaminase (CDA). Severe hematologic toxicity to gemcitabine was reported in patients harboring genetic polymorphisms in CDA gene. High-resolution melting (HRM) analysis of polymerase chain reaction amplicon emerges today as a powerful technique for both genotyping and gene scanning strategies. In this study, 46 DNA samples from gemcitabine-treated patients were subjected to HRM analysis on a LightCycler 480 platform. Residual serum CDA activity was assayed as a surrogate marker for the overall functionality of this enzyme. Genotyping of three well-described single nucleotide polymorphisms in coding region (c.79A>C, c.208G>A and c.435C>T) was successfully achieved by HRM analysis of small polymerase chain reaction fragments, whereas unknown single nucleotide polymorphisms were searched by a gene scanning strategy with longer amplicons (up to 622 bp). The gene scanning strategy allowed us to find a new intronic mutation c.246+37G>A in a female patient displaying marked CDA deficiency and who had an extreme toxic reaction with a fatal outcome to gemcitabine treatment. Our work demonstrates that HRM-based methods, owing to their simplicity, reliability, and speed, are useful tools for diagnosis of CDA deficiency and could be of interest for personalized medicine.

Clinical outcomes with transoral robotic surgery for supraglottic squamous cell carcinoma: Experience of a French evaluation cooperative subgroup of GETTEC

Transoral, minimally invasive, organ preservation surgeries are increasingly used to treat laryngopharyngeal carcinomas to avoid the toxicity associated with combined chemoradiotherapy (CRT) regimens. This study investigated the efficiency, safety, and functional outcomes of using transoral robotic surgery (TORS) to perform supraglottic laryngectomy (SGL).

Transoral minimally invasive robotic surgery for carcinoma of the pharynx and the larynx: a new approach.

Partial laryngectomy is an old but well-accepted surgical treatment for selected carcinomas of the larynx. Actually, the transcervical approach remains the most popular even if the transoral laser approach is useful in some cases. Transoral robotic surgery is a new promising surgical procedure in head and neck oncology as an alternative to conventional surgery with decreased morbidity. The aim of this study is a description of the state of the art by a review of the literature. We emphasize limits and future prospects on this topic with a special focus on dependability.

Updated definition of level VI lymph node classification in the neck

Conclusion. This update will enable us to precisely address the involvement pattern of level VI and to standardize treatment procedures in order to refine their indications and eventually improve their results and avoid treatment morbidity. Background. The neck level classification is being used worldwide to describe the lymph nodes status of the neck. It provides standardized data to properly evaluate and then improve our protocols for the management of neck metastasis in an evidence-based medical manner. Although level VI treatment is challenging in cancer of the larynx, pharynx, trachea, esophagus, and thyroid, our knowledge about its involvement relies on few non-standardized data, due to the inadequate definition of this region. Method. We propose an updated radiological and surgical definition of level VI, with the introduction of two sublevels which fulfill surgical, radiotherapy, radiological, and pathological concerns. Results. Level VIa encompasses prelaryngeal, intercricothyroidal, pretracheal, and perithyroidal nodes. Level VIb encompasses inferior laryngeal nodes. Within the traditional limits of level VI, all lymph nodes lying between the inferior border of the hyoid bone and the inferior border of the cricoid cartilage belong to level VIa. Between the inferior border of the cricoid cartilage and the top of the suprasternal notch, lymph nodes lying in front of the posterior face of the thyroid gland belong to level VIa; those lying behind this boundary belong to level VIb. We also discuss the definition of the superior mediastinal lymph nodes, which should not be mistaken for level VI.

La chirurgieminimale invasive transorale robot-assistée: quelles applications ? Quel avenir ?

Transoral robotic surgery (TORS) is a new technique that provides several unique advantages, which include a three-dimensional magnified view, the ability to see and work around curves or angles, and the availability of two or three robotic arms. Via this review of the literature, we discuss the limits and future prospects on this topic. Preliminary data suggest that TORS may provide a technique for ablation and reconstruction of pharyngeal defects with promising new transoral indications. It may also provide new opportunities of transoral surgery for oropharyngeal and supraglottic carcinoma. TORS is a promising surgical procedure contingent on the development of new associated functions such as an image guidance system. Successful development of this new tool will also depend on the quality of clinical works and research programs.RésuméLa chirurgie transorale robot-assistée (TOAR) offre une vision tridimensionnelle magnifiée du site opératoire qui peut être indirecte, une instrumentation avec une mobilité accrue portée par deux à trois bras, permettant ainsi d’accéder à des espaces anatomiques jusqu’alors difficiles d’accès par voie transorale. L’objet de cet article est d’établir les limites et les perspectives via une revue de la littérature. Les premiers travaux rapportent l’expérience de chirurgie d’exérèse et de reconstruction en région pharyngolaryngée. Le robot chirurgical appliqué en chirurgie endoscopique ORL est un outil prometteur sous réserve, cependant, du développement attendu de nouvelles fonctions comme un système de guidage par l’image. Le bon développement de ce nouvel outil dépendra également de la qualité des travaux et programmes de recherche dans ce domaine.