Independent induction of caspase-8 and cFLIP expression during colorectal carcinogenesis in sporadic and HNPCC adenomas and carcinomas

A Gene-Based Machine Learning Classifier Associated to the Colorectal Adenoma-Carcinoma Sequence

Colorectal cancer (CRC) carcinogenesis is generally the result of the sequential mutation and deletion of various genes; this is known as the normal mucosa–adenoma–carcinoma sequence. The aim of this study was to develop a predictor-classifier during the “adenoma-carcinoma” sequence using microarray gene expression profiles of primary CRC, adenoma, and normal colon epithelial tissues. Four gene expression profiles from the Gene Expression Omnibus database, containing 465 samples (105 normal, 155 adenoma, and 205 CRC), were preprocessed to identify differentially expressed genes (DEGs) between adenoma tissue and primary CRC. The feature selection procedure, using the sequential Boruta algorithm and Stepwise Regression, determined 56 highly important genes. K-Means methods showed that, using the selected 56 DEGs, the three groups were clearly separate. The classification was performed with machine learning algorithms such as Linear Model (LM), Random Forest (RF), k-Nearest Neighbors (k-NN), and Artificial Neural Network (ANN). The best classification method in terms of accuracy (88.06 ± 0.70) and AUC (92.04 ± 0.47) was k-NN. To confirm the relevance of the predictive models, we applied the four models on a validation cohort: the k-NN model remained the best model in terms of performance, with 91.11% accuracy. Among the 56 DEGs, we identified 17 genes with an ascending or descending trend through the normal mucosa–adenoma–carcinoma sequence. Moreover, using the survival information of the TCGA database, we selected six DEGs related to patient prognosis (SCARA5, PKIB, CWH43, TEX11, METTL7A, and VEGFA). The six-gene-based classifier described in the current study could be used as a potential biomarker for the early diagnosis of CRC.

Effect of Oxaliplatin-Loaded Poly (d,l-Lactide-co-Glycolic Acid) (PLGA) Nanoparticles Combined with Retinoic Acid and Cholesterol on Apoptosis, Drug Resistance, and Metastasis Factors of Colorectal Cancer

Apoptosis signaling pathways, drug resistance, and metastasis are important targets to develop new cancer treatments. We developed cholesterol-coated Poly(d,l-Lactide-co-Glycolic Acid) (PLGA) nanoparticles for effective encapsulation and delivery of retinoic acid and oxaliplatin to analyze their antitumor activity in colorectal cancer. The cell viability and proliferation of tumoral cells lines (CT-26 and SW-480) decreased when compared to control in vitro after treatment with the nanoparticles. In addition, apoptosis of CT-26 cells increased. Importantly, cytoprotection of nontumor cells was detected. Expression of pro-apoptotic proteins was upregulated, while anti-apoptotic proteins were downregulated either in vitro or in vivo. In addition, drug resistance and metastasis factors were downregulated in vivo. Human colorectal tumors that highly expressed BCL-2 and Ki-67 had a greater tendency towards death within 60 months. Our results show that loading oxaliplatin combined with retinoic acid and cholesterol in a nanoparticle formulation enables determination of optimal antitumor activity and subsequent treatment efficacy.

Analysis of potential genes and pathways associated with the colorectal normal mucosa-adenoma-carcinoma sequence

This study aimed to identify differentially expressed genes (DEGs) related to the colorectal normal mucosa-adenoma-carcinoma sequence using bioinformatics analysis. Raw data files were downloaded from Gene Expression Omnibus (GEO) and underwent quality assessment and preprocessing. DEGs were analyzed by the limma package in R software (R version 3.3.2). Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed with the DAVID online tool. In a comparison of colorectal adenoma (n = 20) and colorectal cancer (CRC) stage I (n = 31), II (n = 38), III (n = 45), and IV (n = 62) with normal colorectal mucosa (n = 19), we identified 336 common DEGs. Among them, seven DEGs were associated with patient prognosis. Five (HEPACAM2, ITLN1, LGALS2, MUC12, and NXPE1) of the seven genes presented a sequentially descending trend in expression with tumor progression. In contrast, TIMP1 showed a sequentially ascending trend. GCG was constantly downregulated compared with the gene expression level in normal mucosa. The significantly enriched GO terms included extracellular region, extracellular space, protein binding, and carbohydrate binding. The KEGG categories included HIF-1 signaling pathway, insulin secretion, and glucagon signaling pathway. We discovered seven DEGs in the normal colorectal mucosa-adenoma-carcinoma sequence that was associated with CRC patient prognosis. Monitoring changes in these gene expression levels may be a strategy to assess disease progression, evaluate treatment efficacy, and predict prognosis.

Expression Level of Caspase Genes in Colorectal Cancer

Background:

Caspases proteins are protease enzymes involved in the initiation and execution of apoptosis process. Regulation of apoptosis process plays an important role in the normal biological events and development. In addition to developmental abnormalities, dysregulated apoptosis system may lead to tumorigenesis, autoimmunity, and other serious health problems. Aberrant regulation of apoptosis may also be the paramount cause of chemoresistance during cancer therapy. It is aimed through this study to evaluate the transcript levels of Caspase 3, 8, and 9 in tumoral tissues from patients with colorectal cancer (CRC) and compare it with normal marginal tissues.

Methods:

Fifty tumor tissues and their matched marginal tissues, as control group, were obtained from CRC patients. Total mRNA of all tissue samples was extracted and cDNA was synthesized. Using SYBR Green PCR master mix and Real-time gene expression technique, the transcript level of target genes was quantified.

Results:

Experiments indicated that mRNA expressions of caspase 9 and 3 were downregulated in tumoral tissues from CRC patients in comparison to marginal tissues. In contrast, tumoral tissues expressed mRNA of caspase 8 higher than normal marginal tissues. Modified transcript levels of caspase 3, 8, and 9 were correlated with the clinical manifestations of the patients.

Conclusions:

Alteration in the mRNA level of caspase genes may be involved in the development of CRC.

Genetic polymorphisms of the CASP8 gene promoter may not be associated with colorectal cancer in Han Chinese from southwest China

PURPOSE

Caspase 8 (CASP8) plays a critical role in the apoptotic pathway and aberrant regulation of this pathway causes many diseases including cancers. Genetic variants rs3834129 (CTTACT/-) and rs3769821 (T/C) in the promoter region of the CASP8 gene were documented to be associated with multiple solid cancers and non-Hodgkin's lymphoma (NHL), respectively, despite of some controversies. We aimed to discern potential association of these two variants and rs113686495 (CTGTCATT/-), as well as CASP8 mRNA and protein expression levels with colorectal cancer (CRC) in Han Chinese.

METHODS

We genotyped CASP8 genetic variants in 305 CRC patients and 342 healthy individuals from Kunming, Southwest China. Expression levels of CASP8 mRNA and protein were quantified in paired cancerous and paracancerous normal tissues by using real-time quantitative PCR and western blot, respectively. We compared the frequencies of alleles, genotypes, and haplotypes between the cases and controls. Correlation of CASP8 mRNA and protein expression levels in paired cancerous and paracancerous normal tissues from patients with different genotypes and clinical expression were also evaluated.

RESULTS

There was no association of the CASP8 genetic variants with CRC in our case-control study. The CASP8 gene mRNA expression levels in cancerous and paracancerous normal tissues were similar and there was no significant difference between subjects with different genotypes and clinical features. However, we found that CASP8 protein level was significantly lower in cancerous tissues than in paired paracancerous normal tissues.

CONCLUSIONS

Our results suggest that the three CASP8 genetic variants may not be associated with CRC risk in Han Chinese from southwest China. Aberrant CASP8 protein expression may play a role in the pathogenesis of CRC.

Analysis of death receptor 5 and caspase-8 expression in primary and metastatic head and neck squamous cell carcinoma and their prognostic impact

Death receptor 5 (DR5) and caspase-8 are major components in the extrinsic apoptotic pathway. The alterations of the expression of these proteins during the metastasis of head and neck squamous cell carcinoma (HNSCC) and their prognostic impact have not been reported. The present study analyzes the expression of DR5 and caspase-8 by immunohistochemistry (IHC) in primary and metastatic HNSCCs and their impact on patient survival. Tumor samples in this study included 100 primary HNSCC with no evidence of metastasis, 100 primary HNSCC with lymph node metastasis (LNM) and 100 matching LNM. IHC analysis revealed a significant loss or downregulation of DR5 expression in primary tumors with metastasis and their matching LNM compared to primary tumors with no evidence of metastasis. A similar trend was observed in caspase-8 expression although it was not statistically significant. Downregulation of caspase-8 and DR5 expression was significantly correlated with poorly differentiated tumors compared to moderately and well differentiated tumors. Univariate analysis indicates that, in HNSCC with no metastasis, higher expression of caspase-8 significantly correlated with better disease-free survival and overall survival. However, in HNSCC with LNM, higher caspase-8 expression significantly correlated with poorer disease-free survival and overall survival. Similar results were also generated when we combined both DR5 and caspase-8. Taken together, we suggest that both DR5 and caspase-8 are involved in regulation of HNSCC metastasis. Our findings warrant further investigation on the dual role of caspase-8 in cancer development.

Prognostic significance of TRAIL signaling molecules in stage II and III colorectal cancer

PURPOSE

We previously found that cellular FLICE-inhibitory protein (c-FLIP), caspase 8, and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor 2 (DR5) are major regulators of cell viability and chemotherapy-induced apoptosis in colorectal cancer. In this study, we determined the prognostic significance of c-FLIP, caspase 8, TRAIL and DR5 expression in tissues from patients with stage II and III colorectal cancer.

EXPERIMENTAL DESIGN

Tissue microarrays were constructed from matched normal and tumor tissue derived from patients (n = 253) enrolled in a phase III trial of adjuvant 5-fluorouracil-based chemotherapy versus postoperative observation alone. TRAIL, DR5, caspase 8, and c-FLIP expression levels were determined by immunohistochemistry.

RESULTS

Colorectal tumors displayed significantly higher expression levels of c-FLIP (P < 0.001), caspase 8 (P = 0.01), and DR5 (P < 0.001), but lower levels of TRAIL (P < 0.001) compared with matched normal tissue. In univariate analysis, higher TRAIL expression in the tumor was associated with worse overall survival (P = 0.026), with a trend to decreased relapse-free survival (RFS; P = 0.06), and higher tumor c-FLIP expression was associated with a significantly decreased RFS (P = 0.015). Using multivariate predictive modeling for RFS in all patients and including all biomarkers, age, treatment, and stage, we found that the model was significant when the mean tumor c-FLIP expression score and disease stage were included (P < 0.001). As regards overall survival, the overall model was predictive when both TRAIL expression and disease stage were included (P < 0.001).

CONCLUSIONS

High c-FLIP and TRAIL expression may be independent adverse prognostic markers in stage II and III colorectal cancer and might identify patients most at risk of relapse.

Fas ligand expression in lynch syndrome-associated colorectal tumours

Fas Ligand (FasL) expression by cancer cells may contribute to tumour immune escape via the Fas counterattack against tumour-infiltrating lymphocytes (TILs). Whether this plays a role in colorectal carcinogenesis in Lynch syndrome was examined studying FasL expression, tumour cell apoptosis and number of TILs in colorectal neoplasms from Lynch syndrome patients (50 adenomas, 20 carcinomas) compared with sporadic cases (69 adenomas, 52 carcinomas). FasL expression was observed in 94% of Lynch syndrome adenomas and in all carcinomas. FasL expression patterns and apoptotic indices were similar in Lynch syndrome-associated neoplasms and sporadic cases. The number of TILs was higher in Lynch syndrome neoplasms than in sporadic cases. There were no correlations between FasL expression and tumour cell apoptosis or number of TILs in Lynch syndrome-associated neoplasms. So, FasL expression is an early event in Lynch syndrome and sporadic colorectal carcinogenesis, but not related to TIL number. Taken together, our data do not support a role for the Fas counterattack in colorectal carcinogenesis in Lynch syndrome.

Phase II trial of mapatumumab, a fully human agonistic monoclonal antibody that targets and activates the tumour necrosis factor apoptosis-inducing ligand receptor-1 (TRAIL-R1), in patients with refractory colorectal cancer

Background:

Recombinant tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) induces tumour-selective apoptosis in various pre-clinical models by binding its specific receptors expressed on cancer cells. Mapatumumab is a fully human monoclonal antibody that is agonistic to the TRAIL Receptor 1 (TRAIL-R1).

Methods:

This phase II multicentre study was designed to evaluate the efficacy and safety of mapatumumab in patients with colorectal cancer (CRC) who had failed to respond to, were intolerant to, or not candidates for fluoropyrimidine, oxaliplatin, and irinotecan-based regimens. All patients received two loading doses of mapatumumab (20 mg kg⁻¹ every 14 days), followed by maintenance therapy with 10 mg kg⁻¹ infused every 14 days.

Results:

A total of 38 patients, who had progressive disease after a median of three earlier chemotherapy lines, were enrolled. No response according to the Response Evaluation Criteria in Solid Tumors was observed. A total of 12 patients (32%) achieved stable disease for a median of 2.6 months. The median progression-free survival was 1.2 months. The most common adverse events reported, regardless of relationship, were fatigue, nausea, anorexia, and abdominal pain. Plasma mapatumumab concentrations were within the range of exposures predicted by the results of phase I studies of mapatumumab.

Conclusion:

No clinical activity of single-agent mapatumumab was observed in patients with advanced refractory CRC. However, on the basis of its favourable safety profile and pre-clinical evidence of potential synergy in combination with agents commonly used in the treatment of colorectal cancer, further evaluation of mapatumumab in combination with chemotherapy is warranted.