Current and future biomarkers in the treatment of colorectal cancer

A novel cuproptosis-related gene prognostic signature in colon adenocarcinoma

Cuproptosis is the latest cell death type caused by enhanced mitochondrial-dependent energy metabolism. This study plans to establish a survival prognosis model for colon adenocarcinoma (COAD) patients based on cuproptosis-related genes (CRGs). We investigated the genetic alterations of CRGs in COAD based on The Cancer Genome Atlas database and validated in the GSE41328 dataset. Our results showed that LIPT1, PDHA1, GLS, and CDKN2A had significantly higher expression in COAD tissues than in normal tissues, while FDX1, DLD, and MTF1 had significantly lower expression in COAD tissues than in normal tissues (|(log2(fold change))| > 2, p < 0.05). DLD (hazard ratio (HR): 0.658; 95% confidence interval (CI): 0.445, 0.974; p = 0.037) and CDKN2A (HR: 1.785; 95% CI: 1.200, 2.654; p = 0.004) expressions were linked with overall survival throughout a log-rank test. CRG prognostic scores exhibited an area under the curve of 0.737, 0.646, and 0.633 at 1, 3, and 5 years. Patients with a high-risk factor suffered from poor prognosis (HR = 1.514; 95% CI: 1.022, 2.243; p = 0.0386). An independent validation dataset (GSE41328 (N = 20)) confirmed the above results. The CRGs' signature may be used as a prognostic predictor for COAD patients, providing unique insights into anticancer therapy.

Glycoproteomics-based liquid biopsy: translational outlook for colorectal cancer clinical management in Southeast Asia

Colorectal cancer (CRC) signifies a significant healthcare challenge in Southeast Asia. Despite advancements in screening approaches and treatment modalities, significant medical gaps remain, ranging from prevention and early diagnosis to determining targeted therapy and establishing personalized approaches to managing CRC. There is a need to expand more validated biomarkers in clinical practice. An advanced technique incorporating high-throughput mass spectrometry as a liquid biopsy to unravel a repertoire of glycoproteins and glycans would potentially drive the development of clinical tools for CRC screening, diagnosis and monitoring, and it can be further adapted to the existing standard-of-care procedure. Therefore this review offers a perspective on glycoproteomics-driven liquid biopsy and its potential integration into the clinical care of CRC in the southeast Asia region.

CtDNA's prognostic value in patients with early-stage colorectal cancer after surgery: A meta-analysis and systematic review

BACKGROUND

Circulating tumor DNA (ctDNA) positivity has been shown to suggest the presence of minimally residual tumor cells in numerous investigations. We aimed to assess the prognostic value of ctDNA positivity for recurrence-free survival in patients with early-stage colorectal cancer after radical surgery and following adjuvant chemotherapy.

METHODS

We systematically reviewed studies published in English until August 15, 2022, concerning ctDNA and tumor-node-metastasis I to III colorectal cancer after surgery, and quantified the correlation between ctDNA positivity and early-stage (tumor-node-metastasis stage I-III) colorectal cancer using meta-analysis methods.

RESULTS

In total, the meta-analysis comprised 1713 patients from 6 studies. Patients with ctDNA-positive colorectal cancer after surgery had a significantly higher risk of recurrence than patients with ctDNA-negative colorectal cancer (hazard ratio 4.64, 95% confidence interval 2.17-9.92, z = 3.96; P < .001). After adjuvant chemotherapy, patients who were ctDNA-positive had a significantly higher risk of recurrence than those who were ctDNA-negative (hazard ratio 7.27, 95% confidence interval 4.50-11.75, z = 8.1; P < .001).

CONCLUSIONS

CtDNA positivity may potentially be a predictor for early-stage colorectal tumor recurrence following surgery and adjuvant chemotherapy.

Development of a risk model based on immune genes in patients with colon adenocarcinoma

BACKGROUND

The rapidly increasing morbidity and the poor prognosis making the colon adenocarcinoma not only common but also highly malignant. On the other hand, immunotherapy emerges as a therapeutic modality of colon cancer recently. In this study, we developed a prognostic risk model that is based on immune genes, which could predict the overall survival (OS) of patients with colon adenocarcinoma.

METHODS

The Cancer Genome Atlas (TCGA) database was used to download both transcriptomic and clinical data, and the ImmPort database was used to obtain immune genes. The least absolute shrinkage and selection operator (LASSO)-Cox regression was adopted to further select the key genes with prognostic value. Then the key genes were inputted into stepwise regression to calculated each patient's immune-related risk score (immune score). Survival, survminer packages and bilateral tests in R language were adopted to determine the optimal cut-off value (cut-off value) for the risk score. This threshold divides patients into immune-score high-risk and low-risk groups. The differences in the levels of infiltrating immune cells and stromal cells in the high and low immune risk groups were then calculated and compared by the CIBERSORT algorithm.

RESULTS

According to our results, a prognostic risk model was constructed based upon 26 immune-related genes. High immune score was shown to be a poor prognostic factor for colon adenocarcinoma patients, such as overall survival, progress free survival for different therapies, and tumor stages. High immune score was also associated with the abundance of CD4+ T cells and CD8+ T cells. In addition, the high immune score group, the expression levels of LMTK3, LAG3 and PD-L1 were higher than those in the low score group.

CONCLUSION

We developed a 26-immune gene model of colon adenocarcinoma to predict patient's survival. This model might be used in clinical practice as a prognostic instrument for patients diagnosed with colon adenocarcinoma.

Mitochondrial Factor C20orf7 Facilitates the EMT-Mediated Cancer Cell Migration and the Proliferation of Colon Cancer In Vitro and In Vivo

Colon cancer is a major malignant neoplasm with a low survival rate for late-stage patients. Therefore, the investigation of molecules regulating colon cancer progression and the discovery of novel therapeutic targets is critical. Mitochondria play a vital role in maintaining the homeostasis of cells. Abnormal mitochondrial metabolism alterations and the induction of glycolysis can facilitate tumor growth; therefore, targeting mitochondrial molecules is suggested to be a promising strategy for cancer treatment. In this study, we investigated the role of this largely unknown mitochondrial factor, chromosome 20 open reading frame 7 (C20orf7), in colon cancer progression. Clustered regularly interspaced short palindromic repeats (CRISPR) technology was utilized for C20orf7 depletion, and functional assays were performed to examine the regulation of C20orf7 in colon cancer cells. We demonstrated that C20orf7 facilitates epithelial–mesenchymal transition (EMT)-mediated cell migration and promotes the proliferation of colon cancer. The anti-cancer drug 5-fluorouracil (5FU) was also applied, and C20orf7 was targeted with a combination of 5FU treatment, which could further enhance the anti-cancer effect in the colon cancer cell line and the xenograft mice model. In summary, this study demonstrated, for the first time, that C20orf7 plays a promotional role in cancer tumorigenesis and could be a promising therapeutic target in colon cancer treatment.

Hsa_circ_0045932 regulates the progression of colorectal cancer by regulating HK2 through sponging miR-873-5p

Background

Circular RNAs (circRNAs) have been confirmed to be key regulators for colorectal cancer (CRC) progression. The purpose of this research was to explore the biological role and mechanism of hsa_circ_0045932 in CRC.

Methods

RT‐qPCR and Western blot (WB) were applied to examine RNA and protein levels, respectively. MTT assay, EdU assay, and transwell assay were used to detect cell proliferative, migration, and invasion. Glucose uptake and lactic acid level were determined to assess cellular glycolysis. Dual‐luciferase reporter and RIP assays were carried out to detect the relationship between miR‐873‐5p and hsa_circ_0045932 or hexokinase 2 (HK2). Xenograft mice model was established to confirm the function of hsa_circ_0045932 in vivo.

Results

Hsa_circ_0045932 was overexpressed in CRC tissue samples and cells. Hsa_circ_0045932 knockdown repressed CRC cell proliferation, invasion, migration, and glycolysis abilities in vitro. MiR‐873‐5p could be sponged by hsa_circ_0045932, and its inhibitor also reversed the inhibitory effect of hsa_circ_0045932 knockdown on CRC cell progression. HK2 was targeted by miR‐873‐5p, and hsa_circ_0045932 regulated HK2 expression through targeting miR‐873‐5p. Overexpression of HK2 reversed the repressive effect of hsa_circ_0045932 knockdown on CRC cell malignant behaviors. Furthermore, the pro‐tumor role of hsa_circ_0045932 in vivo was also confirmed using animal experiments.

Conclusion

Hsa_circ_0045932 promoted CRC progression through sponging miR‐873‐5p to up‐regulate HK2, which might offer novel therapeutic target for CRC clinical intervention.

Combined analysis of KARS mutation and p16INK4a and p14ARF methylation status in locally advanced rectal carcinoma treated with preoperative chemoradiotherapy

Current management of locally advanced rectal carcinoma (LARC) involves preoperative chemoradiotherapy (preCRT) before surgery. Despite improved local control rate, the response to preCRT of individual patients is variable and may reflect heterogeneous biological properties among tumors of the same clinical stage. Identifying novel molecular parameters with predictive and/or prognostic value is of great clinical importance for a personalized therapeutic approach. In this study, KRAS mutation status was analyzed by direct sequencing, while methylation-specific polymerase chain reaction (MSP) was used to examine p16INK4a and p14ARF gene methylation status in pretreatment tumor biopsies of 60 patients with LARC. The examined molecular changes of KRAS, p16INK4a and p14ARF genes were mutually independent (p16INK4a/KRAS, P=0.272; p14ARF/KRAS, P=0.923; p16INK4a/p14ARF, P=0.715). However, the simultaneous presence of p14ARF methylation and KRAS mutation was associated with a more frequent appearance of local recurrences and distant metastasis (P=0.027). Moreover, patients with the simultaneous presence of p16INK4a and p14ARF methylation and KRAS mutation had significantly shorter overall survival (P=0.011). The obtained results strongly suggest that combined analyses of examined genetic and epigenetic molecular alterations could contribute to the identification of LARC patient subgroups with more aggressive tumor behavior and worse disease outcome.

Expression and prognostic significance of CBX2 in colorectal cancer: database mining for CBX family members in malignancies and vitro analyses

Background

The Chromobox (CBX) domain protein family, a core component of polycomb repressive complexes 1, is involved in transcriptional repression, cell differentiation, and program development by binding to methylated histone tails. Each CBX family member plays a distinct role in various biological processes through their own specific chromatin domains, due to differences in conserved sequences of the CBX proteins. It has been demonstrated that colorectal cancer (CRC) is a multiple-step biological evolutionary process, whereas the roles of the CBX family in CRC remain largely unclear.

Methods

In the present study, the expression and prognostic significance of the CBX family in CRC were systematically analyzed through a series of online databases, including Cancer Cell Line Encyclopedia (CCLE), Oncomine, Human Protein Atlas (HPA), and Gene Expression Profiling Interactive Analysis (GEPIA). For in vitro verification, we performed cell cloning, flow cytometry and transwell experiments to verify the proliferation and invasion ability of CRC cells after knocking down CBX2.

Results

Most CBX proteins were found to be highly expressed in CRC, but only the elevated expression of CBX2 could be associated with poor prognosis in patients with CRC. Further examination of the role of CBX2 in CRC was performed through several in vitro experiments. CBX2 was overexpressed in CRC cell lines via the CCLE database and the results were verified by RT-qPCR. Moreover, the knockdown of CBX2 significantly suppressed CRC cell proliferation and invasion. Furthermore, the downregulation of CBX2 was found to promote CRC cell apoptosis.

Conclusions

Based on these findings, CBX2 may function as an oncogene and potential prognostic biomarker. Thus, the association between the abnormal expression of CBX2 and the initiation of CRC deserves further exploration.

Cyclin A2 maintains colon homeostasis and is a prognostic factor in colorectal cancer

To clarify the function of cyclin A2 in colon homeostasis and colorectal cancer (CRC), we generated mice deficient for cyclin A2 in colonic epithelial cells (CECs). Colons of these mice displayed architectural changes in the mucosa and signs of inflammation, as well as increased proliferation of CECs associated with the appearance of low- and high-grade dysplasias. The main initial events triggering those alterations in cyclin A2-deficient CECs appeared to be abnormal mitoses and DNA damage. Cyclin A2 deletion in CECs promoted the development of dysplasia and adenocarcinomas in a murine colitis-associated cancer model. We next explored the status of cyclin A2 expression in clinical CRC samples at the mRNA and protein levels and found higher expression in tumors of patients with stage 1 or 2 CRC compared with those of patients with stage 3 or 4 CRC. A meta-analysis of 11 transcriptome data sets comprising 2239 primary CRC tumors revealed different expression levels of CCNA2 (the mRNA coding for cyclin A2) among the CRC tumor subtypes, with the highest expression detected in consensus molecular subtype 1 (CMS1) and the lowest in CMS4 tumors. Moreover, we found high expression of CCNA2 to be a new, independent prognosis factor for CRC tumors.

DNA methylation markers detected in blood, stool, urine, and tissue in colorectal cancer: a systematic review of paired samples

PURPOSE

Methylated cell-free DNA in liquid biopsies are promising non-invasive biomarkers for colorectal cancer (CRC). Optimal markers would have high sensitivity and specificity for early detection of CRC and could be detected in more than one type of material from the patient. We systematically reviewed the literature on DNA methylation markers of colorectal cancer, detected in more than one type of material, regarding their potential as contributors to a panel for screening and follow-up of CRC.

METHODS

The databases MEDLINE, Web of Science, and Embase were systematically searched. Data extraction and review was performed by two authors independently. Agreement between methylation status in tissue and other materials (blood/stool/urine) was analyzed using the McNemar test and Cohen's kappa.

RESULTS

From the 51 included studies, we identified seven single markers with sensitivity ≥ 75% and specificity ≥ 90% for CRC. We also identified one promising plasma panel and two stool panels. The correspondence of methylation status was evaluated as very good for four markers, but only marginal for most of the other markers investigated (12 of 21).

CONCLUSION

The included studies reported only some of the variables and markers of interest and included few patients. Hence, a meta-analysis was not possible at this point. Larger, prospective studies must be designed to study the discordant detection of markers in tissue and liquid biopsies. When reporting their findings, such studies should use a standardized format.

Angiogenesis in endometrial carcinoma: Therapies and biomarkers, current options, and future perspectives

Endometrial carcinoma is the most common gynecologic malignancy and the fourth most prevalent cancer in women in the modern world. Despite a relatively high chance of surgical cure, for patients with advanced or recurrent disease there are few therapeutic options. Angiogenesis has been extensively studied ever since vascular endothelial growth factor (VEGF) was discovered in the 1980s. Several clinical trials of anti-angiogenic therapy in endometrial carcinoma have been conducted, with mixed results, and many researchers have tried to determine prognostic and therapeutic biomarkers. Recent trials, which shed new light on possible treatment biomarkers and efficacious combination therapies, are reviewed in this text. While we are still far from effectively tailoring anti-angiogenic treatment to each patient, these data have provided valuable insight and have put us on track for the discovery of novel opportunities for angiogenesis therapy in endometrial carcinoma.

Integration of genetic variants and gene network for drug repurposing in colorectal cancer

Even though many genetic risk loci for human diseases have been identified and comprehensively cataloged, strategies to guide clinical research by integrating the extensive results of genetic studies and biological resources are still limited. Moreover, integrative analyses that provide novel insights into disease biology are expected to be especially useful for drug discovery. Herein, we used text mining of genetic studies on colorectal cancer (CRC) and assigned biological annotations to identified risk genes in order to discover novel drug targets and potential drugs for repurposing. Risk genes for CRC were obtained from PubMed text mining, and for each gene, six functional and bioinformatic annotations were analyzed. The annotations include missense mutations, cis-expression quantitative trait loci (cis-eQTL), molecular pathway analyses, protein-protein interactions (PPIs), a genetic overlap with knockout mouse phenotypes, and primary immunodeficiency (PID). We then prioritized the biological risk candidate genes according to a scoring system of the six functional annotations. Each functional annotation was assigned one point, and those genes with a score ≥2 were designated "biological CRC risk genes". Using this method, we revealed 82 biological CRC risk genes, which were mapped to 128 genes in an expanded PPI network. Further utilizing DrugBank and the Therapeutic Target Database, we found 21 genes in our list that are targeted by 166 candidate drugs. Based on data from ClinicalTrials.gov and literature review, we found four known target genes with six drugs for clinical treatment in CRC, and three target genes with nine drugs supported by previous preclinical results in CRC. Additionally, 12 genes are targeted by 32 drugs approved for other indications, which can possibly be repurposed for CRC treatment. Finally, analysis from Connectivity Map (CMap) showed that 18 drugs have a high potential for CRC.

MicroRNAs for Diagnosis and Treatment of Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer worldwide, with high morbidity and mortality rates. The diagnosis and treatment of CRC have the most significant value for disease- free survival. Early diagnosis and early surgical resection are generally considered to be the most effective ways to reduce CRC mortality. In the past few years, many researchers have focused on the role of microRNAs in different tumors, making the functions of microRNAs gradually clear. The present study reviews the role of microRNAs in the diagnosis and treatment of colorectal cancer. Compared with the usual diagnosis methods and biomarker, circulating microRNAs can be promising new effective biomarkers for CRC diagnosis and treatment.

Serum AMDL DR-70 levels: a new concept in the diagnosis and follow-up of colorectal carcinoma

Aim: The purpose of this study was to determine the diagnostic potential of DR-70 assay in patients with colorectal cancer and to investigate the relationship between serum DR-70 levels and the biological characteristic of the tumor. Patients & methods: The experimental group included patients who were diagnosed with colorectal adenocarcinoma after biopsy specimen. The control group of this study consisted of patients whose total colonoscopy was reported as normal. Results: Serum levels of DR-70 was found to be significantly higher in patients with colorectal cancer than healthy participants (p = 0.001). Receiver operating curve analyses indicated a cut-off value of 1.69 μg/ml for serum DR-70 levels. Stage of the disease, grade of the tumor, number of metastatic lymph nodes and microsatellite instability status were significantly related to serum DR-70 levels (p = 0.001, p = 0.001, p = 0.001 and p = 0.002, respectively). Conclusion: It can be concluded that serum levels of DR-70 can be regarded as an indicator for the diagnosis of colorectal cancer.

Proteogenomic biomarkers in colorectal cancers: clinical applications

INTRODUCTION

Colorectal cancer (CRC) is one of the leading cancers in terms of incidence and mortality, rate requiring a multidisciplinary approach. The discovery of specific CRC biomarkers has caused a paradigm shift in its clinical management.

AREAS COVERED

The aim is to illustrate the possible clinical applications of CRC biomarkers through an updated literature review (from 2015 to 2020) based on the PubMed database. A relationship between cancer localization and genetic profile has been identified. Nowadays, the tumor markers are largely used to select patients that could really benefit from a specific type of adjuvant therapy, in order to optimize treatment programs, especially in metastatic patients. This review highlights both CRC biomarkers' advantages and critical issues.

EXPERT OPINION

New biomarker discoveries allow to set noninvasive tests that could increase patient's compliance with therapy. They also permit a cost-effective early diagnosis, as well as patient-tailored treatments, improving the overall survival. The CRC biomarkers could also have a prognostic value, and usually, they are included in follow-up programs. However, despite the continuous progression of new technologies, their clinical validation is still debated. In this context, additional clinical studies are still necessary to identify, among potential markers, the most effective ones.

Impact of age on N-methyl-N-nitrosourea induced microsatellite instability in young and old C57BL/6J mice

Age is an important factor in the evaluation of chemical toxicology. Chemical carcinogenic compounds can induce genomic mutations. However, few studies have been conducted on the association between genomic mutation frequency, such as microsatellite instability (MSI), and the age of mice treated with a nitrosourea mutagen. In the current work, we treated young (6 weeks) and old (10 months) mice with N-methyl-N-nitrosourea (MNU) for 4 months; the MSI frequency was then measured using polymerase chain reaction (PCR) and short tandem repeat (STR) scanning. The percentage of animals with MSI in the old group was significantly higher than that in the young group (100% and 75%). The frequency of MSI events was significantly different between the two groups as well (15.8% for old and 9.4% for young). The ratio of MSI loci displayed no obvious difference between the two groups. In addition, a few loci, including D15Mit5 and D8Mit14 exhibited the highest frequency of MSI events. Since specific loci showed increased MSI in the present study and a higher frequency in previous studies, these loci could be regarded as "hot spot". These results suggested that old mice would be more susceptible to this mutagen, and prone to accrue MSI. The hot spot microsatellite loci are potentially useful markers for genomic instability analysis.

Image-Based Network Analysis of DNp73 Expression by Immunohistochemistry in Rectal Cancer Patients

Background: Rectal cancer is a disease characterized with tumor heterogeneity. The combination of surgery, radiotherapy, and chemotherapy can reduce the risk of local recurrence. However, there is a significant difference in the response to radiotherapy among rectal cancer patients even they have the same tumor stage. Despite rapid advances in knowledge of cellular functions affecting radiosensitivity, there is still a lack of predictive factors for local recurrence and normal tissue damage. The tumor protein DNp73 is thought as a biomarker in colorectal cancer, but its clinical significance is still not sufficiently investigated, mainly due to the limitation of human-based pathology analysis. In this study, we investigated the predictive value of DNp73 in patients with rectal adenocarcinoma using image-based network analysis.

Methods: The fuzzy weighted recurrence network of time series was extended to handle multi-channel image data, and applied to the analysis of immunohistochemistry images of DNp73 expression obtained from a cohort of 25 rectal cancer patients who underwent radiotherapy before surgery. Two mathematical weighted network properties, which are the clustering coefficient and characteristic path length, were computed for the image-based networks of the primary tumor (obtained after operation) and biopsy (obtained before operation) of each cancer patient.

Results: The ratios of two weighted recurrence network properties of the primary tumors to biopsies reveal the correlation of DNp73 expression and long survival time, and discover the non-effective radiotherapy to a cohort of rectal cancer patients who had short survival time.

Conclusion: Our work contributes to the elucidation of the predictive value of DNp73 expression in rectal cancer patients who were given preoperative radiotherapy. Mathematical properties of fuzzy weighted recurrence networks of immunohistochemistry images are not only able to show the predictive factor of DNp73 expression in the patients, but also reveal the identification of non-effective application of radiotherapy to those who had poor overall survival outcome.

Identification of a 13-gene-based classifier as a potential biomarker to predict the effects of fluorouracil-based chemotherapy in colorectal cancer

The aim of the current study was to develop a predictor classifier for response to fluorouracil-based chemotherapy in patients with advanced colorectal cancer (CRC) using microarray gene expression profiles of primary CRC tissues. Using two expression profiles downloaded from the Gene Expression Omnibus database, differentially expressed genes (DEGs) between responders and non-responders to fluorouracil-based chemotherapy were identified. A total of 791 DEGs, including 303 that were upregulated and 488 that were downregulated in responders, were identified. Functional enrichment analysis revealed that the DEGs were primarily involved in ‘cell mitosis’, ‘DNA replication’ and ‘cell cycle’ signaling pathways. Following feature selection using two methods, a random forest classifier for response to fluorouracil-based chemotherapy with 13 DEGs was constructed. The accuracy of the 13-gene classifier was 0.930 in the training set and 0.810 in the validation set. The receiver operating characteristic curve analysis revealed that the area under the curve was 1.000 in the training set and 0.873 in the validation set (P=0.227). The 13-gene-based classifier described in the current study may be used as a potential biomarker to predict the effects of fluorouracil-based chemotherapy in patients with CRC.

High expression of TFEB is associated with aggressive clinical features in colorectal cancer

Objectives

The transcription factor EB (TFEB), a member of the micropthalmia family, has been found to be associated with autophagy and upregulated in some kinds of tumors. However, very few studies focused on TFEB in colorectal cancer (CRC). TFEB expression status and its relevance to clinical features in CRC would be analyzed in this study.

Materials and methods

Real-time PCR, Western blot, and immunohistological staining were used to evaluate TFEB expression in CRC tissues and adjacent normal tissues, and the role of TFEB in CRC cell lines was investigated in vitro and in vivo.

Results

TFEB was expressed at lower level in CRC tissues than normal in both mRNA and protein level. However, there were significantly positive correlations between TFEB expression in cancer tissues and malignant progression of CRC. Cancers with TFEB overexpression always had deeper infiltration and higher lymphatic metastasis rate. Furthermore, patients with high TFEB levels always had poor survival, and higher TFEB expression could be a predictor of survival in multivariate analysis. Meanwhile, knockdown TFEB by shRNA or knockout TFEB by sgRNA in CRC cell lines could significantly inhibit cell proliferation and migration in amino acid-free medium. In addition, we found a positive relationship between TFEB and Beclin1 expression, and silencing TFEB inhibited Beclin1 expression in CRC cells.

Conclusion

TFEB expression correlated with aggressive clinical features in CRC, and higher TFEB expression could be a prognostic factor and potential treatment target of CRC.

High expression of Ras-related protein 1A promotes an aggressive phenotype in colorectal cancer via PTEN/FOXO3/CCND1 pathway

Background

Colorectal cancer (CRC) is a commonly diagnosed digestive malignancy worldwide. Ras-related protein 1A (RAP1A) is a member of the Ras superfamily of small GTPases and has been recently identified as a novel oncoprotein in several human malignancies. However, its specific role in CRC remains unclear.

Method

In this study, we firstly analyzed its expression and clinical significance in a retrospective cohort of 144 CRC patients. Then, cellular assays in vitro and in vivo were performed to clarify its biological role in CRC cells. Finally, microarray analysis was utilized to investigate the molecular mechanisms regulated by RAP1A in CRC progression.

Results

Firstly, RAP1A expression was abnormally higher in CRC tissues as compared with adjacent normal tissues, and significantly correlated tumor invasion. High RAP1A expression was an independent unfavourable prognostic factor for CRC patients. Combining RAP1A expression and preoperative CEA level contributed to a more accurate prognostic stratification in CRC patients. Secondly, knockdown of RAP1A dramatically inhibited the growth of CRC cells, while it was opposite for RAP1A overexpression. Finally, the microarray analysis revealed RAP1A promoted CRC growth partly through phosphatase and tensin homolog (PTEN)/forkhead box O3(FOXO3)/cyclin D1(CCND1) signaling pathway. FOXO3 overexpression could partly mimic the inhibitory effect of RAP1A knockdown in CRC growth. Moreover, FOXO3 overexpression inhibited CCND1 expression, but had no impact on RAP1A and PTEN expression.

Conclusion

RAP1A promotes CRC development partly through PTEN/FOXO3 /CCND1 signaling pathway. It has a great potential to be an effective clinical biomarker and therapeutic target for CRC patients.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0827-y) contains supplementary material, which is available to authorized users.

Angiodrastic Chemokines in Colorectal Cancer: Clinicopathological Correlations

Aim

To study the expression of angiodrastic chemokines in colorectal tumors and correlate findings with clinicopathological parameters and survival.

Methods

The proangiogenic factor VEGF, the angiogenic chemokines CXCL8 and CXCL6, and the angiostatic chemokine CXCL4 were measured by ELISA in tumor and normal tissue of 35 stage II and III patients and correlated with the histopathology markers Ki67, p53, p21, bcl2, EGFR, and MLH1 and 5-year survival. The Wilcoxon and chi-square tests were used for statistical comparisons.

Results

There was a significant increase of CXCL6 (p = 0.005) and VEGF (p = 0.003) in cancerous tissue compared to normal. Patients with lower levels of CXCL8 and CXCL4 lived significantly longer. Patients with loss of EGFR expression had higher levels of CXCL8 while p21 loss was associated with higher levels of CXCL6. Chemokine levels were not correlated with TNM or Dukes classification. Strong expression of p53 was accompanied by decreased survival.

Conclusions

(1) The angiogenic factors CXCL6 and VEGF are increased in colorectal cancer tissue with no association with the clinical stage of the disease or survival. (2) However, increased levels of tissue CXCL8 and CXCL4 are associated with poor survival. (3) Strong expression of p53 is found in patients with poor survival.

Tumor Heterogeneity in Colorectal Cancer: What Do We Know So Far?

Colorectal cancer is not one disease but rather a collection of neoplastic diseases. Due to heterogeneity in the disease biology, therapy response, and prognosis, extensive disease stratification is required. Therefore, TNM stage, microsatellite status, tumor grade, lymphovascular invasion, and other parameters are assessed in the pathology report to indicate the extent and prognosis of the disease. The mutation status of KRAS, BRAF, and NRAS is also investigated in a metastatic context to predict the response to anti-EGFR therapy. Recently, 4 distinct molecular subtypes of colorectal cancer have been described that have both prognostic and therapeutic relevance. In addition, characterization of the inflammatory infiltrate revealed major differences in the amount and location of inflammatory cells in distinct colorectal tumor types. Together, all of these parameters help to stratify patients into different therapeutic and prognostic subgroups. However, this stratification is not unambiguous since tumors often display intratumoral heterogeneity, whereby several subpopulations within one tumor show differences in morphology, inflammatory infiltrate, mutational status, or gene expression profile. This article gives an overview of all of the current known data with regard to tumor heterogeneity at both inter- and intratumoral levels.