Establishment of patient-derived tumor organoids to functionally inform treatment decisions in metastatic colorectal cancer.

BACKGROUND: Metastatic colorectal cancer (mCRC) patients tend to have modest benefits from molecularly driven therapeutics. Patient-derived tumor organoids (PDTOs) represent an unmatched model to elucidate tumor resistance to therapy, due to their high capacity to resemble tumor characteristics. MATERIALS AND METHODS: We used viable tumor tissue from two cohorts of patients with mCRC, naïve or refractory to treatment, respectively, for generating PDTOs. The derived models were subjected to a 6-day drug screening assay (DSA) with a comprehensive pipeline of chemotherapy and targeted drugs against almost all the actionable mCRC molecular drivers. For the second cohort DSA data were matched with those from PDTO genotyping. RESULTS: A total of 40 PDTOs included in the two cohorts were derived from mCRC primary tumors or metastases. The first cohort included 31 PDTOs derived from patients treated in front line. For this cohort, DSA results were matched with patient responses. Moreover, RAS/BRAF mutational status was matched with DSA cetuximab response. Ten out of 12 (83.3%) RAS wild-type PDTOs responded to cetuximab, while all the mutant PDTOs, 8 out of 8 (100%), were resistant. For the second cohort (chemorefractory patients), we used part of tumor tissue for genotyping. Four out of nine DSA/genotyping data resulted applicable in the clinic. Two RAS-mutant mCRC patients have been treated with FOLFOX-bevacizumab and mitomycin-capecitabine in third line, respectively, based on DSA results, obtaining disease control. One patient was treated with nivolumab-second mitochondrial-derived activator of caspases mimetic (phase I trial) due to high tumor mutational burden at genotyping, experiencing stable disease. In one case, the presence of BRCA2 mutation correlated with DSA sensitivity to olaparib; however, the patient could not receive the therapy. CONCLUSIONS: Using CRC as a model, we have designed and validated a clinically applicable methodology to potentially inform clinical decisions with functional data. Undoubtedly, further larger analyses are needed to improve methodology success rates and propose suitable treatment strategies for mCRC patients.

Inherited predisposition to malignant mesothelioma: germline BAP1 mutations and beyond.

Malignant mesothelioma (MM) is a rare aggressive neoplasm arising from mesothelial lining of body cavities, most commonly pleura and peritoneum. It is characterised by a poor prognosis and limited treatment options. A universally recognised risk factor for the development of MM is exposure to asbestos. However, evidence supporting a genetic susceptibility to the development of MM has been accumulating during the last decades. Intensive research for the identification of MM susceptibility genes has led to the discovery of BAP1 and to the definition of the so-called "BAP1-related tumour predisposition syndrome". Patients carrying germline BAP1 mutations have an increased risk for the early development of tumours, including MMs, uveal melanomas, cutaneous melanocytic lesions, clear cell renal cell carcinomas and basal cell carcinomas. Furthermore, pathogenic variants in tumour suppressor genes with a role in DNA repair have been recently described in families with clustered MM cases. These genetic alterations seem to confer exaggerate sensitivity to asbestos carcinogenic effect and, arguably, increased response to specific chemotherapeutic strategies. While the translational significance of BAP1 alterations is explored in the research field, the identification of families carrying germline BAP1 mutations is mandatory to start appropriate surveillance programs and guarantee the best clinical management to these patients.

Three dimensional primary cultures for selecting human breast cancers that are sensitive to the anti-tumor activity of ipatasertib or taselisib in combination with anti-microtubule cytotoxic drugs.

Two inhibitors of phosphatidylinositol 3-kinase (PI3K) pathway taselisib, targeting the mutant PI3K-subunit-alpha (PI3KA) and ipatasertib, AKT-inhibitor, are currently under clinical investigation in breast cancer (BC) patients. We have previously demonstrated the anti-tumor efficacy of these anti-PI3K/AKT-inibitors in combination with anti-microtubule drugs in human BC cell lines, through a complete cytoskeleton disorganization. In this work, we generated ex-vivo three-dimensional (3D) cultures from human BC as a model to test drug efficacy and to identify new molecular biomarkers for selection of BC patients suitable for anti-PI3K/AKT-inibitors treatment. We have established 3D cultures from 25/27 human BC samples, in which the ability of growth in vitro replicates the clinical and biological aggressiveness of the original tumors. According to the results of next generation sequencing analysis, a direct correlation was found between PI3KA mutations and the sensitivity in 3D models in vitro to taselisib and ipatasertib alone and combined with anti-microtubule agents. Moreover, mutations in HER and MAPK families related genes, including EGFR, KRAS and BRAF, were found in resistant samples, suggesting their potential role as negative predictive factors of response to these agents. Thus, we demonstrated that ex vivo 3D cultures from human BC patients allow a rapid and efficient drug screening for chemotherapies and targeted agents in genetically selected patients and represent an innovative model to identify new biomarkers of drug resistance.

Nonalcoholic fatty pancreas disease and Nonalcoholic fatty liver disease: more than ectopic fat.

OBJECTIVE: The aim of this study was to evaluate the metabolic effects of fatty pancreas (nonalcoholic fatty pancreas disease - NAFPD) in a group of obese paediatric patients with nonalcoholic fatty liver disease (NAFLD). METHODS: We included 121 consecutive children with echographic evidence of hepatic steatosis. All patients underwent to abdominal ultrasound to evaluate pancreatic echogenic pattern. We divided the patients into two groups on the basis of the presence of fatty pancreas. In all patients liver function tests, lipid and gluco-insulinemic profile were evaluated. A selected subset of patients (67) underwent to liver biopsy. RESULTS: Of these 121 patients, 58 showed NAFPD and 63 patients exhibited a normal pancreatic echogenic pattern. No differences were found in age, transaminases serum levels, lipid profile and pancreatic enzymes between the two groups. The patients with NAFPD had a significantly higher z-BMI, fasting insulin, insulin resistance (HOMA-IR) and lower ISI respect to the group without fatty pancreas. The patients with fatty pancreas showed a more advanced form of liver disease, with higher values of fibrosis, ballooning and NAS score with respect to the group without NAFPD. CONCLUSIONS: Our study demonstrated that NAFPD is a frequent condition in obese paediatric patients affected by NAFLD. Our data suggest that pancreatic fat should not be considered an inert accumulation of fat, but as an additional factor able to affect glucose metabolism and severity of liver disease, increasing the risk of develop metabolic syndrome.