NDRG4 stratifies the prognostic value of body mass index in colorectal cancer

Post-diagnosis adiposity and colorectal cancer prognosis: A Global Cancer Update Programme (CUP Global) systematic literature review and meta-analysis

The adiposity influence on colorectal cancer prognosis remains poorly characterised. We performed a systematic review and meta-analysis on post-diagnosis adiposity measures (body mass index [BMI], waist circumference, waist-to-hip ratio, weight) or their changes and colorectal cancer outcomes. PubMed and Embase were searched through 28 February 2022. Random-effects meta-analyses were conducted when at least three studies had sufficient information. The quality of evidence was interpreted and graded by the Global Cancer Update Programme (CUP Global) independent Expert Committee on Cancer Survivorship and Expert Panel. We reviewed 124 observational studies (85 publications). Meta-analyses were possible for BMI and all-cause mortality, colorectal cancer-specific mortality, and cancer recurrence/disease-free survival. Non-linear meta-analysis indicated a reverse J-shaped association between BMI and colorectal cancer outcomes (nadir at BMI 28 kg/m2). The highest risk, relative to the nadir, was observed at both ends of the BMI distribution (18 and 38 kg/m2), namely 60% and 23% higher risk for all-cause mortality; 95% and 26% for colorectal cancer-specific mortality; and 37% and 24% for cancer recurrence/disease-free survival, respectively. The higher risk with low BMI was attenuated in secondary analyses of RCTs (compared to cohort studies), among studies with longer follow-up, and in women suggesting potential methodological limitations and/or altered physiological state. Descriptively synthesised studies on other adiposity-outcome associations of interest were limited in number and methodological quality. All the associations were graded as limited (likelihood of causality: no conclusion) due to potential methodological limitations (reverse causation, confounding, selection bias). Additional well-designed observational studies and interventional trials are needed to provide further clarification.

Colon cancer transcriptome

Over the last four decades, methodological innovations have continuously changed transcriptome profiling. It is now feasible to sequence and quantify the transcriptional outputs of individual cells or thousands of samples using RNA sequencing (RNA-seq). These transcriptomes serve as a connection between cellular behaviors and their underlying molecular mechanisms, such as mutations. This relationship, in the context of cancer, provides a chance to unravel tumor complexity and heterogeneity and uncover novel biomarkers or treatment options. Since colon cancer is one of the most frequent malignancies, its prognosis and diagnosis seem to be critical. The transcriptome technology is developing for an earlier and more accurate diagnosis of cancer which can provide better protectivity and prognostic utility to medical teams and patients. A transcriptome is a whole set of expressed coding and non-coding RNAs in an individual or cell population. The cancer transcriptome includes RNA-based changes. The combined genome and transcriptome of a patient may provide a comprehensive picture of their cancer, and this information is beginning to affect treatment decision-making in real-time. A full assessment of the transcriptome of colon (colorectal) cancer has been assessed in this review paper based on risk factors such as age, obesity, gender, alcohol use, race, and also different stages of cancer, as well as non-coding RNAs like circRNAs, miRNAs, lncRNAs, and siRNAs. Similarly, they have been examined independently in the transcriptome study of colon cancer.

Novel Methylation Biomarkers for Colorectal Cancer Prognosis

Colorectal cancer (CRC) comprises the third most common cancer worldwide and the second regarding number of deaths. In order to make a correct and early diagnosis to predict metastasis formation, biomarkers are an important tool. Although there are multiple signaling pathways associated with cancer progression, the most recognized are the MAPK pathway, p53 pathway, and TGF-β pathway. These pathways regulate many important functions in the cell, such as cell cycle regulation, proliferation, differentiation, and metastasis formation, among others. Changes in expression in genes belonging to these pathways are drivers of carcinogenesis. Often these expression changes are caused by mutations; however, epigenetic changes, such as DNA methylation, are increasingly acknowledged to play a role in the deregulation of oncogenic genes. This makes DNA methylation changes an interesting biomarkers in cancer. Among the newly identified biomarkers for CRC metastasis INHBB, SMOC2, BDNF, and TBRG4 are included, all of which are highly deregulated by methylation and closely associated with metastasis. The identification of such biomarkers in metastasis of CRC may allow a better treatment and early identification of cancer formation in order to perform better diagnostics and improve the life expectancy.

NDRG4 sensitizes CRC cells to 5-FU by upregulating DDIT3 expression

The incidence of colorectal cancer (CRC) has remained high in recent years, and 5-fluorouracil (5-FU) is a vital chemotherapeutic agent for its treatment. Our previous study reported that N-myc downstream-regulated gene 4 (NDRG4) plays a tumor-suppressive role in CRC, but the mechanisms associated with NDRG4 and 5-FU chemosensitivity remain unclear. The results of the present study demonstrate that NDRG4 sensitized CRC cells to 5-FU by upregulating DNA damage inducible transcript 3 (DDIT3). NDRG4 inhibited the proliferation of CRC cells and the activation of PI3K/AKT and ERK signaling. Furthermore, NDRG4 promoted CRC cell apoptosis induced by 5-FU. Mechanistic analyses revealed that NDRG4 upregulated DDIT3 expression, and that the proapoptotic effect of NDRG4 under 5-FU treatment conditions was dependent on DDIT3. These findings support the biological value of the association between NDRG4, DDIT3 and 5-FU chemosensitivity in CRC, and may advance the clinical treatment of CRC in the future.

Association of Obesity With Survival Outcomes in Patients With Cancer: A Systematic Review and Meta-analysis

Importance

Obesity, defined as a body mass index (BMI) greater than 30, is associated with a significant increase in the risk of many cancers and in overall mortality. However, various studies have suggested that patients with cancer and no obesity (ie, BMI 20-25) have worse outcomes than patients with obesity.

Objective

To assess the association between obesity and outcomes after a diagnosis of cancer.

Data Sources

PubMed, the Cochrane Library, and EMBASE were searched from inception to January 2020.

Study Selection

Studies reporting prognosis of patients with obesity using standard BMI categories and cancer were included. Studies that used nonstandard BMI categories, that were limited to children, or that were limited to patients with hematological malignant neoplasms were excluded. Screening was performed independently by multiple reviewers. Among 1892 retrieved studies, 203 (17%) met inclusion criteria for initial evaluation.

Data Extraction and Synthesis

The Meta-analysis of Observational Studies in Epidemiology (MOOSE) and Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines were reporting guideline was followed. Data were extracted by multiple independent reviewers. Risk of death, cancer-specific mortality, and recurrence were pooled to provide an adjusted hazard ratio (HR) with a 95% CI . A random-effects model was used for the retrospective nature of studies.

Main Outcomes and Measures

The primary outcome of the study was overall survival (OS) in patients with cancer, with and without obesity. Secondary end points were cancer-specific survival (CSS) and progression-free survival (PFS) or disease-free survival (DFS). The risk of events was reported as HRs with 95% CIs, with an HR greater than 1 associated with a worse outcome among patients with obesity vs those without.

Results

A total of 203 studies with 6 320 365 participants evaluated the association of OS, CSS, and/or PFS or DFS with obesity in patients with cancer. Overall, obesity was associated with a reduced OS (HR, 1.14; 95% CI, 1.09-1.19; P < .001) and CSS (HR, 1.17; 95% CI, 1.12-1.23; P < .001). Patients were also at increased risk of recurrence (HR, 1.13; 95% CI, 1.07-1.19; P < .001). Conversely, patients with obesity and lung cancer, renal cell carcinoma, or melanoma had better survival outcomes compared with patients without obesity and the same cancer (lung: HR, 0.86; 95% CI, 0.76-0.98; P = .02; renal cell: HR, 0.74; 95% CI, 0.53-0.89; P = .02; melanoma: HR, 0.74; 95% CI, 0.57-0.96; P < .001).

Conclusions and Relevance

In this study, obesity was associated with greater mortality overall in patients with cancer. However, patients with obesity and lung cancer, renal cell carcinoma, and melanoma had a lower risk of death than patients with the same cancers without obesity. Weight-reducing strategies may represent effective measures for reducing mortality in these patients.

MiR-433 Regulates Myocardial Ischemia Reperfusion Injury by Targeting NDRG4 Via the PI3K/Akt Pathway

BACKGROUND AND PURPOSE

Myocardial ischemia reperfusion (IR) injury is a serious issue in the treatment of myocardial infarction. MiR-433 is upregulated in myocardial IR injury, but its specific effects remain unclear. In this study, we explored the effect and mechanism of miR-433 in myocardial IR injury.

METHODS

The expression of miR-433 was measured by qRT-PCR. H9c2 cells were transfected with miR-433 mimic and inhibitor after exposure to HR, respectively. Cell viability was detected by MTT. Cell apoptosis was measured by flow cytometry. Protein expression was assessed by western blot. Dual-luciferase reporter assay was performed to assess the target reaction between miR-433 and NDRG4. In vivo rat model of IR was used, and antagomiR-433 was injected to IR rats.

RESULTS

The qRT-PCR results showed that miR-433 expression increased in H9c2 cardiomyocytes after exposure to HR. Transfection with miR-433 inhibitor significantly increased cell viability, reduced LDH and apoptosis, downregulated Bax level, and upregulated Bcl-2 level. In contrast, the miR-433 mimic significantly augmented the HR-induced effects. Dual-luciferase reporter assay and western blot analysis suggested that miR-433 directly targeted NDRG4. NDRG4 silencing abrogated the protection of miR-433 inhibition on HR injury in H9c2 cells. It also reversed PI3K/Akt pathway activation that was induced by miR-433 inhibition. MiR-433 inhibition significantly decreased CK-MB and LDH serum level in IR rats. And NDRG4, p-PI3K, and p-Akt protein expression was elevated by antagomiR-433 injection in vivo.

CONCLUSION

MiR-433 regulated myocardial IR injury by targeting NDRG4 and modulating PI3K/Akt signal pathway.

NDRG4 in gastric cancer determines tumor cell proliferation and clinical outcome

As a novel candidate tumor suppressor, NDRG4 is largely unstudied in human malignancies. In this study, we investigated the protein expression level of NDRG4 in gastric cancer and its association with outcome of patients. In the present study, we recruited 286 patients with gastric cancer and investigated the protein and mRNA expression of NDRG4 in cancer and adjacent normal specimens by immunohistochemistry assay and real-time PCR. The association of NDRG4 level with clinicopathological characteristics was investigated by appropriate statistical analysis. NDRG4 overexpression and knockdown cell lines were established in order to detect its impact on proliferation and apoptosis. Significant decreased protein and mRNA expression of NDRG4 was found in gastric cancer, compared with adjacent normal specimens. Besides, it was found that NDRG4 protein expression in gastric cancer was significantly associated with tumor differentiation, invasion, metastasis, and stage. Patients with tumors of decreased NDRG4 level were more likely to have unfavorable disease-free and overall survival, in both univariate and multivariate analysis. In addition, overexpression of NDRG4 suppressed cell proliferation of gastric cancer cells in vitro; conversely, the proliferation of gastric cancer cells were enhanced by knockdown of NDRG4. These results proved for the first time that NDRG4 could be a potential tumor suppressor and prognostic marker of gastric cancer.

NDRG4, an early detection marker for colorectal cancer, is specifically expressed in enteric neurons

BACKGROUND

Promoter methylation of N-myc Downstream-Regulated Gene 4 (NDRG4) in fecal DNA is an established early detection marker for colorectal cancer (CRC). Despite its connection to CRC, NDRG4 is predominantly studied in brain and heart, with little to no knowledge about its expression or role in other organs. In this study, we aimed to determine the whole-body expression of NDRG4, with a focus on the intestinal tract.

METHODS

We investigated NDRG4 expression throughout the body by immunohistochemistry, Western Blotting and in situ mRNA hybridization using tissues from NDRG4 wild-type, heterozygous and knockout mice and humans. In addition, we explored cell-specific expression of NDRG4 in murine whole-mount gut preparations using immunofluorescence and confocal microscopy.

KEY RESULTS

NDRG4 is specifically expressed within nervous system structures throughout the body. In the intestinal tract of both mouse and man, NDRG4 immunoreactivity was restricted to the enteric nervous system (ENS), where it labeled cell bodies of the myenteric and submucosal plexuses and interconnecting nerve fibers. More precisely, NDRG4 expression was limited to neurons, as NDRG4 always co-localized with HuC/D (pan-neuronal marker) but never with GFAP (an enteric glial cell marker). Furthermore, NDRG4 was expressed in various neuropeptide Y positive neurons, but was only found in a minority (~10%) of neurons expressing neuronal nitric oxide synthase.

CONCLUSIONS AND INFERENCES

NDRG4 is exclusively expressed by central, peripheral and enteric neurons/nerves, suggesting a neuronal-specific role of this protein. Our findings raise the question whether NDRG4, via the ENS, an understudied component of the tumor microenvironment, supports CRC development and/or progression.

Direct Downregulation of B-Cell Translocation Gene 3 by microRNA-93 Is Required for Desensitizing Esophageal Cancer to Radiotherapy

BACKGROUND

Esophageal squamous carcinoma (ESC) is one of the most fatal malignancies worldwide with increasing occurrences yet poor outcome. MicroRNAs were reported to play roles in ESC.

AIMS

We aimed to understand how miRNAs affect the radiotherapy resistance of ESC.

METHODS

MicroRNA assays, real-time PCR, and Western blot were performed for expression analysis of miR-93 and BTG3. Luciferase activity assay was conducted with mutated B-cell translocation gene 3 (BTG3) 3'-UTR sequence in the 3' end of luciferase sequence with miR-93 inhibitor. ESC cells were treated with irradiation (IR) and clonogenic assay was utilized to detect the cell viability. Human ESC xenograft mouse model was established and subjected to target IR treatment followed by tumor size analysis.

RESULTS

MiR-93 was decreased and BTG3 was increased in ESC cells, with negative correlation of their expression in ESC tissues. MiR-93 directly targeted BTG3 3'-UTR by luciferase activity assay. Either miR-93 inhibition or BTG3 overexpression decreased radiation resistance. Furthermore, miR-93 inhibition suppressed radiation resistance through BTG3.

CONCLUSIONS

Direct downregulation of BTG3 by miR-93 is able to render ESC resistant to radiotherapy, and both BTG3 and miR-93 may potentially serve as clinical markers for ESC and contribute to the treatment of ESC.