Organoids from colorectal peritoneal metastases as a platform for improving hyperthermic intraperitoneal chemotherapy.

BACKGROUND: Patients with peritoneal metastases from colorectal cancer have a poor prognosis. If the intraperitoneal tumour load is limited, patients may be eligible for cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy (HIPEC). This treatment has improved overall survival, but recurrence rates are high. The aim of this study was to create a preclinical platform for the development of more effective intraperitoneal chemotherapy strategies. METHODS: Using organoid technology, five tumour cultures were generated from malignant ascites and resected peritoneal metastases. These were used in an in vitro HIPEC model to assess sensitivity to mitomycin C (MMC) and oxaliplatin, the drugs used most commonly in HIPEC. The model was also used to test a rational combination treatment involving MMC and inhibitors of the checkpoint kinase ATR. RESULTS: MMC was more effective in eliminating peritoneal metastasis-derived organoids than oxaliplatin at clinically relevant concentrations. However, the drug concentrations required to eliminate 50 per cent of the tumour cells (IC50) were higher than the median clinical dose in two of five organoid lines for MMC, and all five lines for oxaliplatin, indicating a general resistance to monotherapy. ATR inhibition increased the sensitivity of all peritoneal metastasis-derived organoids to MMC, as the IC50 decreased 2·6-12·4-fold to well below concentrations commonly attained in clinical practice. Live-cell imaging and flow cytometric analysis showed that ATR inhibition did not release cells from MMC-induced cell cycle arrest, but caused increased replication stress and accelerated cell death. CONCLUSION: Peritoneal metastasis-derived organoids can be used to evaluate existing HIPEC regimens on an individual-patient level and for development of more effective treatment strategies. Surgical relevance Cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy (HIPEC) has improved prognosis of patients with peritoneal metastases from colorectal cancer, but disease recurrence is common. More effective and personalized HIPEC is urgently needed. Organoid technology is frequently used for drug screens, as patient-derived organoids can accurately predict clinical therapeutic response in vitro. A panel of organoids was established from peritoneal metastases from colorectal cancer and used to develop a model for testing HIPEC regimens in vitro. Patient-derived organoids differed in sensitivity to commonly used chemotherapeutics, in line with variable clinical outcomes following cytoreductive surgery-HIPEC. Combining MMC with an ATR inhibitor improved the efficacy of MMC. Peritoneal metastasis-derived organoids can be used as a platform to test novel (combination) strategies that increase HIPEC efficacy. In the future, organoids could be used to select patent-tailored HIPEC regimens.

ANTECEDENTES: Los pacientes con metástasis peritoneales (peritoneal metastasis, PM) de cáncer colorrectal tienen un mal pronóstico. Si la carga tumoral intraperitoneal es reducida, los pacientes pueden ser candidatos a cirugía citorreductora seguida de quimioterapia intraperitoneal hipertérmica (hyperthermic intraperitoneal chemotherapy, HIPEC). Este tratamiento ha mejorado la supervivencia global, pero las tasas de recidiva son altas. El objetivo de este estudio fue crear una plataforma preclínica para el desarrollo de las estrategias de quimioterapia intraperitoneal más efectivas. MÉTODOS: Mediante la utilización de la tecnología de organoides, se generaron cinco cultivos tumorales a partir de ascitis maligna y PM resecadas. Se utilizó un modelo de HIPEC in vitro para evaluar la sensibilidad a la mitomicina C (mitomycin C, MMC) y al oxaliplatino, los fármacos más utilizados en la HIPEC. El modelo también se usó para probar un tratamiento combinado de MMC e inhibidores de control inmunitario de la quinasa ATR. RESULTADOS: A concentraciones clínicamente relevantes, la MMC fue más efectiva que el oxaliplatino para eliminar los organoides derivados de PM. Sin embargo, las concentraciones de fármaco necesarias para eliminar el 50% de las células tumorales (IC50) fueron más elevadas que la mediana de la dosis clínica en 2/5 (MMC) o 5/5 (oxaliplatino) de las líneas de organoides, lo que indica una resistencia general a la monoterapia. La inhibición de ATR aumentó la sensibilidad a MMC de todos los organoides derivados de PM, ya que la IC50 disminuyó (2,6-12,4 veces) a concentraciones muy por debajo de las que se alcanzan comúnmente en la práctica clínica. Los análisis de viabilidad celular y de citometría de flujo (FACS) mostraron que la inhibición de ATR no liberaba células tras la detención del ciclo celular inducida por la MMC, sino que causaba un aumento en el estrés replicativo y muerte celular acelerada. CONCLUSIÓN: Se pueden usar los organoides derivados de PM para evaluar los regímenes HIPEC existentes a nivel del paciente individual y para desarrollar estrategias terapéuticas más efectivas.

Histopathological and molecular classification of colorectal cancer and corresponding peritoneal metastases.

BACKGROUND: Patients with colorectal peritoneal carcinomatosis have a very poor prognosis. The recently developed consensus molecular subtype (CMS) classification of primary colorectal cancer categorizes tumours into four robust subtypes, which could guide subtype-targeted therapy. CMS4, also known as the mesenchymal subtype, has the greatest propensity to form distant metastases. CMS4 status and histopathological features of colorectal peritoneal carcinomatosis were investigated in this study. METHODS: Fresh-frozen tissue samples from primary colorectal cancer and paired peritoneal metastases from patients who underwent cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy were collected. Histopathological features were analysed, and a reverse transcriptase-quantitative PCR test was used to assess CMS4 status of all collected lesions. RESULTS: Colorectal peritoneal carcinomatosis was associated with adverse histopathological characteristics, including a high percentage of stroma in both primary tumours and metastases, and poor differentiation grade and high-grade tumour budding in primary tumours. Furthermore, CMS4 was significantly enriched in primary tumours with peritoneal metastases, compared with unselected stage I-IV tumours (60 per cent (12 of 20) versus 23 per cent; P = 0.002). The majority of peritoneal metastases (75 per cent, 21 of 28) were also classified as CMS4. Considerable intrapatient subtype heterogeneity was observed. Notably, 15 of 16 patients with paired tumours had at least one CMS4-positive tumour location. CONCLUSION: Significant enrichment for CMS4 was observed in colorectal peritoneal carcinomatosis. Surgical relevance Cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) improves survival of selected patients with colorectal peritoneal carcinomatosis, but recurrence is common. Histopathological and molecular analysis of colorectal peritoneal carcinomatosis could provide clues for development of novel therapies. In this study, colorectal peritoneal carcinomatosis was found to be enriched for tumours with high stromal content and CMS4-positive status. To further improve prognosis for patients with colorectal peritoneal carcinomatosis, therapies that target tumour-stroma interaction could be added to CRS-HIPEC.

Neoadjuvant chemotherapy affects molecular classification of colorectal tumors.

The recent discovery of 'molecular subtypes' in human primary colorectal cancer has revealed correlations between subtype, propensity to metastasize and response to therapy. It is currently not known whether the molecular tumor subtype is maintained after distant spread. If this is the case, molecular subtyping of the primary tumor could guide subtype-targeted therapy of metastatic disease. In this study, we classified paired samples of primary colorectal carcinomas and their corresponding liver metastases (n=129) as epithelial-like or mesenchymal-like, using a recently developed immunohistochemistry-based classification tool. We observed considerable discordance (45%) in the classification of primary tumors and their liver metastases. Discordant classification was significantly associated with the use of neoadjuvant chemotherapy. Furthermore, gene expression analysis of chemotherapy-exposed versus chemotherapy naive liver metastases revealed expression of a mesenchymal program in pre-treated tumors. To explore whether chemotherapy could cause gene expression changes influencing molecular subtyping, we exposed patient-derived colonospheres to six short cycles of 5-fluorouracil. Gene expression profiling and signature enrichment analysis subsequently revealed that the expression of signatures identifying mesenchymal-like tumors was strongly increased in chemotherapy-exposed tumor cultures. Unsupervised clustering of large cohorts of human colon tumors with the chemotherapy-induced gene expression program identified a poor prognosis mesenchymal-like subgroup. We conclude that neoadjuvant chemotherapy induces a mesenchymal phenotype in residual tumor cells and that this may influence the molecular classification of colorectal tumors.

Imatinib treatment of poor prognosis mesenchymal-type primary colon cancer: a proof-of-concept study in the preoperative window period (ImPACCT).

BACKGROUND: The identification of four Consensus Molecular Subtypes (CMS1-4) of colorectal cancer forms a new paradigm for the design and evaluation of subtype-directed therapeutic strategies. The most aggressive subtype - CMS4 - has the highest chance of disease recurrence. Novel adjuvant therapies for patients with CMS4 tumours are therefore urgently needed. CMS4 tumours are characterized by expression of mesenchymal and stem-like genes. Previous pre-clinical work has shown that targeting Platelet-Derived Growth Factor Receptors (PDGFRs) and the related KIT receptor with imatinib is potentially effective against mesenchymal-type colon cancer. In the present study we aim to provide proof for the concept that imatinib can reduce the aggressive phenotype of primary CMS4 colon cancer. METHODS: Tumour biopsies from patients with newly diagnosed stage I-III colon cancer will be analysed with a novel RT-qPCR test to pre-select patients with CMS4 tumours. Selected patients (n = 27) will receive treatment with imatinib (400 mg per day) starting two weeks prior to planned tumour resection. To assess treatment-induced changes in the aggressive CMS4 phenotype, RNA sequencing will be performed on pre- and post-treatment tissue samples. DISCUSSION: The development of effective adjuvant therapy for primary colon cancer is hindered by multiple factors. First, new drugs that may have value in the prevention of (early) distant recurrence are almost always first tested in patients with heavily pre-treated metastatic disease. Second, measuring on-target drug effects and biological consequences in tumour tissue is not commonly a part of the study design. Third, due to the lack of patient selection tools, clinical trials in the adjuvant setting require large patient populations. Finally, the evaluation of recurrence-prevention requires a long-term follow-up. In the ImPACCT trial these issues are addressed by including newly diagnosed pre-selected patients with CMS4 tumours prior to primary tumour resection, rather than non-selected patients with late-stage disease. By making use of the pre-operative window period, the biological effect of imatinib treatment on CMS4 tumours can be rapidly assessed. Delivering proof-of-concept for drug action in early stage disease should form the basis for the design of future trials with subtype-targeted therapies in colon cancer patients. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02685046 . Registration date: February 9, 2016.

The time to progression ratio: a new individualized volumetric parameter for the early detection of clinical benefit of targeted therapies.

BACKGROUND: Early signs of efficacy are critical in drug development. Response Evaluation Criteria in Solid Tumors (RECIST) are commonly used to determine the efficacy of anti-cancer therapy in clinical trials. RECIST, however, emphasizes the value of tumor shrinkage, while many targeted agents induce prolonged tumor growth arrest. This limits its use for the detection of treatment efficacy for these more cytostatic regimens. Therefore, we designed an individualized variant of a time to progression (TTP) end point based on prospective volumetric measurements and an intra-patient control, the TTP ratio. PATIENTS AND METHODS: Patients with any metastatic malignancy, without regular treatment options, were treated with the mTOR inhibitor everolimus. Treatment response was determined using both RECIST and the TTP ratio. The TTP ratio was defined as the volumetric pretreatment TTP divided by the volumetric on-treatment TTP. A patient was classified as a responder if the TTP ratio was <0.7. Consistency and reproducibility of volumetric measurements were determined. RESULTS: Seventy-three patients were included of whom 59 started treatment. A TTP ratio could be established in 73% (n = 43) of the treated patients. The inter-observer agreement for volumetric progression was 0.78 (95% confidence interval 0.70-0.87) (Krippendorff's α-coefficient). According to RECIST, 35 patients (59%) had stable disease (SD) and 1 patient demonstrated a partial response (PR), whereas only 21 patients (36%) met the prespecified criteria for treatment efficacy according to the TTP ratio. Treatment response according to both the TTP ratio and RECIST (SD + PR) correlated with overall survival (OS) [P(log-rank) < 0.001]. The TTP ratio, however, was also able to differentiate which patients had a better OS within the RECIST SD group [P(log-rank) = 0.0496]. CONCLUSION: The TTP ratio had a high inter-observer agreement, correlated with OS and identified which patients within the RECIST SD group had a longer OS. CLINICALTRIALSGOV IDENTIFIER: NCT01566279.

Safety, efficacy, and long-term follow-up evaluation of perioperative epirubicin, Cisplatin, and capecitabine chemotherapy in esophageal resection for adenocarcinoma.

BACKGROUND: Perioperative epirubicin, cisplatin, and capecitabine (ECC) chemotherapy was evaluated in patients who underwent esophageal resection for adenocarcinoma of the esophagus or gastroesophageal junction (GEJ). METHODS: A cohort of 93 consecutive patients was analyzed. The median follow-up period was 60 months. Source data verification of adverse events was performed by two independent observers. RESULTS: All three planned preoperative chemotherapy cycles were administered to 65 patients (69.9 %). Only 27 % of the patients completed both pre- and postoperative chemotherapy. The reasons for not receiving postoperative adjuvant chemotherapy could be separated in two main problems: toxicity of the preoperative chemotherapy and postoperative problems involving difficulty in recovery and postoperative complications. Finally, 25 patients (27 %), completed three preoperative and three postoperative cycles. Grades 3 and 4 nonhematologic adverse events of preoperative chemotherapy mainly consisted of thromboembolic events (16.2 %) and cardiac complications (7.5 %). A history of cardiac and vascular disease was independently associated with discontinuation of preoperative chemotherapy and the occurrence of grade 3 or higher adverse events. Surgery was performed for 94 % of all the patients who started with ECC chemotherapy. A radical resection (R0) was achieved in 93 % of the patients. A complete pathologic response was observed in 8 % of the patients. During a median follow-up period of 60 months, the median disease-free survival time was 28 months, and the median overall survival time was 36 months. The 3-year overall survival rate was 50 %, and the 5-year overall survival rate was 42 %. CONCLUSION: For patients with adenocarcinoma of the esophagus or GEJ, six cycles of ECC-based perioperative chemotherapy is associated with a relatively high number of adverse events. Although this toxicity did not affect the esophageal resectability rate, this regimen should be used with caution in this patient population.