Adjuvant postoperative radiotherapy for colon carcinoma

The survival benefit of adjuvant radiotherapy for pathological T4N2M0 colon cancer in the Modern Chemotherapy Era: evidence from the SEER database 2004-2015

Neoadjuvant chemoradiotherapy has been established as the standard treatment for patients with locally advanced rectal cancer. However, the role of radiotherapy (RT) has not been fully confirmed in advanced colon cancer (LACC). We postulated that patients with pathological T4N2 locally advanced colon cancer would benefit more from RT. 6715 pT4N2M0 colon cancer patients were included in the Surveillance, Epidemiology, and End Results (SEER) database. The primary endpoints were 5-year overall survival (OS) and cancer-specific survival (CSS). Propensity score matching (PSM) with Kaplan-Meier and Cox proportional hazards' models was performed to estimate prognosis. Before PSM, patients underwent RT had better OS and CSS as compared to patients did not receive RT (OS: 40.1% vs 27.6%, p < .001; CSS: 49.6% vs 41.1%, p = .002). After PSM, 239 matched pairs were formed for further analysis. RT group also presented significantly improved prognosis (OS: 40.1% vs 25.7%, p = .008; CSS: 49.6% vs 38.2%, p = .042). Multivariable Cox regression analysis showed that RT was a protective factor [OS：Hazard ratio (HR) =0.677, 95% Confidence interval (CI): 0.532-0.862, p = .002; CSS: HR = 0.708, 95% CI: 0.533-0.941, p = .018]. For pT4N2M0 colon cancer patients, the addition of RT seems to confer survival benefit as compared to patients who did not receive RT.

Nitidine chloride inhibits the appearance of cancer stem-like properties and regulates potential the mitochondrial membrane alterations of colon cancer cells

Background

Nitidine chloride (NC) is a natural alkaloid that can inhibit tumor growth and induce apoptosis in varieties of cancers. However, the effec12/268t of NC on colon cancer (CC) cells has not been extensively studied.

Methods

Conlon cancer SW480 cells was treated with different concentrations of NC (0.25, 0.5, 1, 2.5, 5, 10, 25, 50, 100, and 200 µM) in DMEM medium for 24 hours. Western blotting (WB) was used to detect the expression of related proteins, such as Ki67, PCNA, NANOG, SOX2, OCT4, Bcl-2, Bax, Caspase-3, Caspase-9, ERK1/2, p-ERK1/2, AKT, p-AKT, STAT3, p-STAT3, P65 and p-P65. The pellet formation experiment was used to detect the pellet formation of stem cells. The JC-1 experiment was used to detect the change of mitochondrial membrane potential. Kit was performed to detect the activity of superoxide dismutase (SOD) and the content of malondialdehyde (MDA). In vivo experiments were used to verify the results of in vitro experiments. TUNEL assay was designed to detect the apoptosis in mice tissue. IHC was used to detect expression of Ki67 and OCT4 protein in tissue.

Results

NC significantly inhibited the expression levels of Ki-67 and a proliferating cell nuclear antigen (PCNA). NC can reduce the pellet colony and pellet size of tumor stem cells and block the stem cell characteristics of CC cells. The corresponding stem cell marker molecules NANOG, SOX2, and OCT4 were also downregulated. NC treatment induced the mitochondrial membrane potential depolarization of CC cells. The expression of pro-apoptotic proteins such as caspase-3, caspase-9, and Bax were upregulated, while the expression level of apoptotic Bcl-2 was significantly down-regulated. Moreover, NC reduced SOD activity and MDA content in CC cells. In addition, studies on pathway phosphorylation have shown that NC inhibits the expression of p-erk and p-akt proteins. Finally, the results were further confirmed by experiments in nude mice. NC inhibited tumor growth in mice. NC promoted apoptosis in tissues. NC inhibited the expression of Ki67 and OCT4 in tissues. NC inhibited the phosphorylation of pathway proteins ERK1/2 and AKT in tissues.

Conclusions

NC treatment inhibited the proliferation and stemness of CC tissues, promoted the apoptosis of tumor tissues, downregulated the expression of p-ERK and p-AKT in tumor tissues, which suggests that NC may play an important role in regulating ERK and AKT pathways.

Identification of potential therapeutic targets for colorectal cancer by bioinformatics analysis

The aim of the present study was to identify potential therapeutic targets for colorectal cancer (CRC). The gene expression profile GSE32323, containing 34 samples, including 17 specimens of CRC tissues and 17 of paired normal tissues from CRC patients, was downloaded from the Gene Expression Omnibus database. Following data preprocessing using the Affy and preprocessCore packages, the differentially-expressed genes (DEGs) between the two types of samples were identified with the Linear Models for Microarray Analysis package. Next, functional and pathway enrichment analysis of the DEGs was performed using the Database for Annotation Visualization and Integrated Discovery. The protein-protein interaction (PPI) network was established using the Search Tool for the Retrieval of Interacting Genes database. Utilizing WebGestalt, the potential microRNAs (miRNAs/miRs) of the DEGs were screened and the integrated miRNA-target network was built. A cohort of 1,347 DEGs was identified, the majority of which were mainly enriched in cell cycle-related biological processes and pathways. Cyclin-dependent kinase 1 (CDK1), cyclin B1 (CCNB1), MAD2 mitotic arrest deficient-like 1 (MAD2L1) and BUB1 mitotic checkpoint serine/threonine kinase B (BUB1B) were prominent in the PPI network, while the over-represented genes in the integrated miRNA-target network were SRY (sex determining region Y)-box 4 (SOX4; targeted by hsa-mir-129), v-myc avian myelocytomatosis viral oncogene homolog (MYC; targeted by hsa-let-7c and hsa-mir-145) and cyclin D1 (CCND1; targeted by hsa-let-7b). CDK1, CCNB1 and CCND1 were also associated with the p53 signaling pathway. Overall, several genes associated with the cell cycle and p53 pathway were identified as biomarkers for CRC. CDK1, CCNB1, MAD2L1, BUB1B, SOX4, collagen type I α2 chain and MYC may play significant roles in CRC progression by affecting the cell cycle-related pathways, while CDK1, CCNB1 and CCND1 may serve as crucial regulators in the p53 signaling pathway. Furthermore, SOX4, MYC and CCND1 may be targets of miR-129, hsa-mir-145 and hsa-let-7c, respectively. However, further validation of these data is required.

Surgical resection of locally advanced primary transverse colon cancer--not a worse outcome in stage II tumor

BACKGROUND AND AIMS

In locally advanced primary transverse colon cancer, a tumor may cause perforation or invade adjacent organs. Extensive resection is the best choice of treatment, but such procedures must be weighed against the potential survival benefits. This study was performed to identify the clinicopathological features and treatment outcomes of such tumors.

MATERIALS AND METHODS

We retrospectively reviewed the database of the Colorectal Cancer Registry of Chang Gung Memorial Hospital between February 1995 and December 2005. Patients with colon cancer sited between the hepatic and splenic flexure that involved an adjacent organ without distant metastasis were defined as having locally advanced transverse colon cancer.

RESULTS

A total of 827 patients who underwent surgery for transverse primary colon cancer were enrolled in the study. Stage II and stage III colon cancer were diagnosed in 548 patients. Thirty-two (5.8%) patients were diagnosed with locally advanced tumors. Multivariate analysis revealed that stage III, preoperative carcinoembryonic antigen ≥5 ng/mL, a tumor with perforation or obstruction, and the presence of a locally advanced tumor were significant prognostic factors for both overall and cancer-specific survival. Postoperative morbidity rates differed significantly between the locally advanced and non-locally advanced tumor groups (22.7% vs. 12.3%, P < 0.01). No significant overall survival difference was observed among the stage II transverse colon tumors (P = 0.21).

CONCLUSION

Surgical resection of locally advanced transverse colon tumors resulted in a higher morbidity and mortality than that of non-locally advanced tumors, but the benefit of extensive surgery in the case of locally advanced tumors cannot be underestimated. Furthermore, this benefit is more pronounced in the case of stage II tumors.

High frequency induction of mitotic recombination by ionizing radiation in Mlh1 null mouse cells

Mitotic recombination in somatic cells involves crossover events between homologous autosomal chromosomes. This process can convert a cell with a heterozygous deficiency to one with a homozygous deficiency if a mutant allele is present on one of the two homologous autosomes. Thus mitotic recombination often represents the second mutational step in tumor suppressor gene inactivation. In this study we examined the frequency and spectrum of ionizing radiation (IR)-induced autosomal mutations affecting Aprt expression in a mouse kidney cell line null for the Mlh1 mismatch repair (MMR) gene. The mutant frequency results demonstrated high frequency induction of mutations by IR exposure and the spectral analysis revealed that most of this response was due to the induction of mitotic recombinational events. High frequency induction of mitotic recombination was not observed in a DNA repair-proficient cell line or in a cell line with an MMR-independent mutator phenotype. These results demonstrate that IR exposure can initiate a process leading to mitotic recombinational events and that MMR function suppresses these events from occurring.

Adjuvant treatment strategies for early colon cancer

Colon cancer remains a major cause of death; however, in the last 3 years a number of trials have been published that have led to changes in the treatment of patients with this disease. Initially, the adjuvant treatment of patients following curative resection was based on their Dukes staging; this is now being refined by consideration of other pathological factors, as well as the investigation of newer prognostic markers such as p53, Ki67 and a number of genes on chromosome 18. Tumours generally develop from the progressive accumulation of genetic events, although some develop through mutation or inactivation of DNA mismatch repair proteins leading to microsatellite instability; this is particularly important in Lynch's syndrome. The loss of gene expression can occur by deletion or mutation of genes or by aberrant methylation of CpG islands. In patients with Dukes C colon cancer the standard of care for adjuvant chemotherapy was previously based on bolus fluorouracil (5-fluorouracil) and folinic acid (leucovorin) administered 5 days per month or weekly for 6 months. Recent studies with a combination of infusional fluorouracil, folinic acid and oxaliplatin have been found to be superior. A further study replacing fluorouracil with oral capecitabine has also demonstrated equivalent disease-free survival. Although some debate remains regarding the benefit of adjuvant treatment for patients with Dukes B colon cancer, the emerging consensus is that, for those patients who are younger and have high-risk features, chemotherapy should be discussed. A number of large vaccine trials have also been conducted in the adjuvant setting and, overall, these have been disappointing. This is a rapidly advancing area of therapy and the results of new trials are awaited to determine whether additional benefits can be achieved with biological therapies such as anti-vascular endothelial growth factor and anti-epithelial growth factor receptor monoclonal antibodies, which have already been shown to be effective in setting of metastatic colon cancer.