Application of tumoroids derived from advanced colorectal cancer patients to predict individual response to chemotherapy.

Therapeutic approaches of advanced colorectal cancer are more complex, here we present a living biobank of patient-derived tumoroids from advanced colorectal cancer patients and show examples of how these tumoroids can be used to to simulate cancer behavior ex vivo and provide more evidence for tumoroids could be utilized as a predictive platform during chemotherapy treatment to identify the chemotherapy response. Morphological, histological and genomic characterization analysis of colorectal cancer tumoroids was conducted. Further, we treated colorectal cancer tumoroids with different drugs to detect cellular activities to evaluate drug sensitivity using CellTiter-Glo 3 D cell viability assay. Then the drug sensitivity of tumoroids was compared with clinical outcomes. Our results implied that tumoroids recapitulated the histological features of the original tumours and genotypic profiling of tumoroids showed a high-level of similarity to the matched primary tumours. Dose-response curves, area under the curve and tumour inhibitory rate of each therapeutic profiling calculations in tumoroids demonstrated a great diversity and we gained 88.24% match ratio between the sensitivity data of tumoroids with their paired patients' clinical outcomes. tumour inhibitory rate of each treatment parameters in tumoroids performed positive correlation with progression-free survival while area under the curve of each treatment parameters performed negative correlation with progression-free survival of the corresponding patients. In summary, We presented a living biobank of tumoroids from advanced colorectal cancer patients and show tumoroids got great potential for predicting clinical responses to chemotherapy treatment of advanced colorectal cancer.

lncRNA GAS5 inhibits malignant progression by regulating macroautophagy and forms a negative feedback regulatory loop with the miR­34a/mTOR/SIRT1 pathway in colorectal cancer.

Long non­coding RNA growth arrest specific 5 (GAS5) exerts inhibitory effects through the modulation of several target microRNAs (miRs) in cancer. However, its potential roles and underlying relationship during colorectal cancer (CRC) progression are unclear. Therefore, we explored the role of the negative feedback loop formed by the GAS5/miR­34a axis and mammalian target of rapamycin/sirtuin 1 (mTOR/SIRT1) pathway on macroautophagy and apoptosis in CRC. Expression of GAS5, miR­34a, SIRT1 and mTOR in CRC patients and cell lines was detected by quantitative reverse transcription polymerase chain reaction. Online bioinformatic analysis was used to predict the downstream miRs of GAS5. Luciferase assay and western blotting were performed to demonstrate miR­34a as a downstream target gene of GAS5 in CRC cells. The effects of the GAS5/miR­34a axis on apoptosis, macroautophagy, and the mTOR/SIRT1 pathway were assessed by flow cytometry, transmission electron microscopy and western blotting, respectively. Our results suggested that GAS5 was downregulated and acted as a molecular sponge of miR­34a during CRC progression. miR­34a participated in regulating GAS5­suppressed CRC cell macroautophagy and induced apoptosis through the mTOR/SIRT1 pathway. GAS5­mediated macroautophagy was maintained in an equilibrium state that might have a protective effect on CRC cell apoptosis. The mTOR signaling pathway suppressed GAS5 expression and formed a negative regulation feedback loop with miR­34a in CRC cells. Our results suggested that the GAS5/miR­34a/SIRT1/mTOR negative regulatory feedback loop mediated CRC cell macroautophagy, and maintained the cells in an autonomous equilibrium state, but not excessive activation state, which functions as a strong antiapoptotic phenotype during human CRC progression.

miR-34a mediates oxaliplatin resistance of colorectal cancer cells by inhibiting macroautophagy via transforming growth factor-ß/Smad4 pathway.

AIM: To investigate whether microRNA (miR)-34a mediates oxaliplatin (OXA) resistance of colorectal cancer (CRC) cells by inhibiting macroautophagy via the transforming growth factor (TGF)-ß/Smad4 pathway. METHODS: miR-34a expression levels were detected in CRC tissues and CRC cell lines by quantitative real-time polymerase chain reaction. Computational search, functional luciferase assay and western blotting were used to demonstrate the downstream target of miR-34a in CRC cells. Cell viability was measured with Cell Counting Kit-8. Apoptosis and macroautophagy of CRC cells were analyzed by flow cytometry and transmission electron microscopy, and expression of beclin I and LC3-II was detected by western blotting. RESULTS: Expression of miR-34a was significantly reduced while expression of TGF-ß and Smad4 was increased in CRC patients treated with OXA-based chemotherapy. OXA treatment also resulted in decreased miR-34a levels and increased TGF-ß and Smad4 levels in both parental cells and the OXA-resistant CRC cells. Activation of macroautophagy contributed to OXA resistance in CRC cells. Expression levels of Smad4 and miR-34a in CRC patients had a significant inverse correlation and overexpressing miR-34a inhibited macroautophagy activation by directly targeting Smad4 through the TGF-ß/Smad4 pathway. OXA-induced downregulation of miR-34a and increased drug resistance by activating macroautophagy in CRC cells. CONCLUSION: miR-34a mediates OXA resistance of CRC by inhibiting macroautophagy via the TGF-ß/Smad4 pathway.

[Surgical treatment and prognosis of cancer of hepatic flexure of colon invading the duodenum in 65 patients].

OBJECTIVE: To discuss surgical treatment of right colon carcinoma of hepatic flexure invading the duodenum. METHODS: Sixty-five patients with right colon carcinoma of hepatic flexure invading the duodenum, treated in our department from 1987 to 2007, were included in this study. Their clinicopathological data were retrospectively reviewed and analyzed. All the cases were divided into three types (local invasion, regional invasion, and cancer with internal fistula) according to duodenal defect, including local invasion (< 2.0 cm), wide invasion (> 2.0 cm) and the presence of internal fistula. RESULTS: 25 patients with local invasion underwent en bloc resection of the duodenal wall. Pedicled ileal flap was used to cover the large duodenal defect measuring 2.0 - 3.0 cm in 5 patients. Dudenojejunostomy was used to reconstruct the large defect measuring more than 5 cm in 3 patients. Conservative resection of right-sided colon was performed in 18 patients with wide invasion. 4 patients underwent pancreaticoduodenectomy combined with right hemicolectomy for colon cancer involving the pancreatic head. 10 underwent duodenal diverticularization. One patient with anastomotic leakage healed within 3 weeks. Other patients were cured without postoperative complications. The total 3-year and 5-year survival rates after surgery were 53.8% and 9.2%, respectively. CONCLUSION: The surgical procedure to be performed is usually decided according to the cancer location, extent, and duodenal defect and invasion, which are important for prolonging life time, improving of quality of life and prognosis in these patients.