MRI-Based Radiomic Models Outperform Radiologists in Predicting Pathological Complete Response to Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer.

RATIONALE AND OBJECTIVES: The 15%-27% of patients with locally advanced rectal cancer (LARC) achieved pathologic complete response (pCR) to neoadjuvant chemoradiotherapy (nCRT) and could avoid proctectomy. We aimed to investigate the effectiveness of treatment response prediction using MRI-based pre-, post-, and delta-radiomic features for LARC patients treated with nCRT and to compare these radiomic models with radiologists' visual assessment. MATERIALS AND METHODS: A total of 126 patients with LARC who received nCRT before surgery were included and randomly divided into a training set (n = 84) and a validation set (n = 42). 250 radiomic features were extracted from T2-weighted images from pre- and post-nCRT MRI. Pearson correlation analysis and AONVA or Relief were used to identify radiomic descriptors associated with pCR. Five machine-learning classifiers were compared to construct radiomic models. The radiomic nomogram was built via multivariate logistic regression analysis. Two senior radiologists independently rated tumor regression grades and compared with radiomic models. Area under the curve (AUC) of the models and pooled observers were compared by using the DeLong test. RESULTS: The optimal pre-, post-, and delta-radiomic models yielded an AUC of 0.717 (95% CI: 0.639-0.795), 0.805 (95%CI: 0.736-0.874), and 0.724 (95%CI: 0.648-0.800), respectively. The radiomic nomogram based on pre-nCRT cN stage, pre-nCRT radscore, and post-nCRT radscore achieved an AUC of 0.852 (95%CI: 0.774-0.930), which was higher than the single radiomic models and pooled readers (all p < 0.05). CONCLUSIONS: The radiomic nomogram is an effective and invasive tool to predict pCR in LARC patients after nCRT, which outperforms radiologists.

Regulation of cancer progression by circRNA and functional proteins.

Circular RNAs (circRNAs) are closed back-splicing products of precursor mRNA in eukaryotes. Compared with linear mRNAs, circRNAs have a special structure and stable expression. A large number of studies have provided different regulatory mechanisms of circRNAs in tumors. Challenges exist in understanding the control of circRNAs because of their sequence overlap with linear mRNA. Here, we survey the most recent progress regarding the regulation of circRNA biogenesis by RNA-binding proteins, one of the vital functional proteins. Furthermore, substantial circRNAs exert compelling biological roles by acting as protein sponges, by being translated themselves or regulating posttranslational modifications of proteins. This review will help further explore more types of functional proteins that interact with circRNA in cancer and reveal other unknown mechanisms of circRNA regulation.

Long noncoding RNA EPB41L4A-AS1 functions as an oncogene by regulating the Rho/ROCK pathway in colorectal cancer.

Colorectal cancer (CRC) is one of the most common malignant tumors worldwide. In terms of cancer-related death, colon cancer ranks second and third among men and women, respectively, and the incidence is increasing annually. Accumulating evidence have indicated that long noncoding RNA (lncRNA) plays an important role in tumorigenesis. In this study, we found that lncRNA EPB41L4A-AS1 was highly expressed in CRC tissues and was associated with poor prognosis and tumor metastasis in patients with CRC. In vitro studies showed that the knockdown of EPB41L4A-AS1 inhibited the proliferation, migration, invasion, and epithelial-mesenchymal transition of CRC cells. Mechanically, we found that EPB41L4A-AS1 may participate in the development of CRC by activating the Rho/Rho-associated protein kinase signaling pathway. Collectively, these results demonstrated that EPB41L4A-AS1 can promote the proliferation, invasion, and migration of CRC, and it may be a novel biomarker for the diagnosis and targeted treatment of CRC.

The Biogenesis, Biology, and Clinical Significance of Exosomal PD-L1 in Cancer.

The exosome serves as a trafficking vehicle for transport of programmed death-ligand 1 (PD-L1) into receptor cells. In tumor microenvironment, distant tumor cells can remotely attack activated T cells by exosomal PD-L1. Here, we summerize the biogenesis and transport process of exosomal PD-L1. Then, we focus on the cancer biology of exosomal PD-L1 in immunosuppression and the mechanism by which it inhibits T cells. Finally, we highlight the prospects of exosomal PD-L1 as a tumor biomarker and its significance in immunotherapy. In addition, we discuss the new challenges faced in researching and utilizing exosomal PD-L1. This review may shed light on the exosomal PD-L1 from the bench to the clinic. Exosomes serve as trafficking vehicles for transport of programmed death-ligand 1 (PD-L1) into receptor cells. In tumor microenvironment, distant tumor cells can remotely attack activated T cells through exosomal PD-L1. Here, we have summarized the biogenesis and transport of exosomal PD-L1. Next, we focused on the cancer biology of exosomal PD-L1 in immunosuppression and the mechanism by which it inhibits T cells. Finally, we highlighted the prospects of exosomal PD-L1 as a tumor biomarker and its significance in immunotherapy. In addition, we have discussed the new challenges faced in studying and utilizing exosomal PD-L1. This review may shed light on the translation of exosomal PD-L1 from bench to clinic.

LncRNA DNAJC3-AS1 Regulates Fatty Acid Synthase via the EGFR Pathway to Promote the Progression of Colorectal Cancer.

Colorectal cancer (CRC) is one of the most common cancers worldwide. Recent studies have shown that long non-coding RNAs (lncRNAs) are involved in tumorigenesis and the development of CRC. By constructing a differential lncRNA expression profile, we screened gene chips and found that DNAJC3-AS1 was highly expressed in CRC tissues and was associated with poor prognosis in patients with CRC. Further, we proved through assays such as wound healing, colony formation, and Cell Counting Kit-8 (CCK8) that interfering with DNAJC3-AS1 could reduce the proliferation, migration, and invasion of CRC cells. Mechanically, we found that DNAJC3-AS1 regulates fatty acid synthase to promote the progression of CRC via the epidermal growth factor receptor/phosphatidylinositol 3-kinase/protein kinase B/nuclear factor κB signaling pathway. Therefore, DNAJC3-AS1 may be a new target for the diagnosis and therapy of CRC.

LncRNA SLCO4A1-AS1 predicts poor prognosis and promotes proliferation and metastasis via the EGFR/MAPK pathway in colorectal cancer.

It is universally acknowledged that long non-coding RNAs (lncRNAs) involved in tumorigenesis in human cancers. However, the function and mechanism of many lncRNAs in colorectal cancer (CRC) remain unclear. By analyzing the two sets of CRC-related gene microarrays data, downloaded from the Gene Expression Omnibus (GEO) database and the lncRNA expression in a set of RNA sequencing data, we found that lncRNA SLCO4A1-AS1 was significantly upregulated in CRC tissues. We then collected CRC tissue samples and verified that SLCO4A1-AS1 is highly expressed in CRC tissues. Furthermore, SLCO4A1-AS1 was also upregulated in the CRC cell line. In situ hybridization results showed that high expression of SLCO4A1-AS1 was associated with poor prognosis in patients with CRC. Next, we found that SLCO4A1-AS1 promoted CRC cell proliferation, migration, and invasion. Results of western blotting assays show that its mechanism may relate to the epidermal growth factor receptor (EGFR)/mitogen-activated protein kinase (MAPK) pathway. Therefore, SLCO4A1-AS1 may be a potential biomarker for CRC prognosis and a new target for colorectal cancer therapy.

LncRNA WWC2-AS1 functions AS a novel competing endogenous RNA in the regulation of FGF2 expression by sponging miR-16 in radiation-induced intestinal fibrosis.

BACKGROUND: Recently, long non-coding RNAs (lncRNAs) were considered as important gene expression regulators involving various biological processes. In this study, we explored the role of lncRNAs in the pathogenesis of radiation-induced intestinal fibrosis (RIF). METHODS: LncRNAs were screened by microarray (Human LncRNA Array v3.0, Arraystar, Inc.) and the differentially expressed lncRNAs in RIF and non-RIF were analyzed by bioinformatics methods. The expression of WWC2-AS1/miR-16/FGF2 axis was compared on mRNA and protein level between human intestinal CCD-18Co fibroblasts cell lines and subepithelial SEMFs in response to radiation treatment. The significance of WWC2-AS1 in regulating FGF2 associated proliferation, migration, invasion and fibrosis of CCD-18Co and SEMFs by exposure to radiation was analyzed by shRNA (WWC2-AS1 shRNA) knock-down of endogenous WWC2-AS1. RESULTS: WWC2-AS1 and FGF2 level was significantly higher while miR-16 was down-regulated in radiation-treated intestinal tissues. WWC2-AS1 more potently boosted FGF2 expression via reducing miR-16, and WWC2-AS1 shRNA remarkably inhibited FGF2 associated proliferation, migration, invasion and fibrosis of radiation treatment in vitro, further demonstrating physical interaction between miR-16 and WWC2-AS1 in radiation-induced fibrosis progress. CONCLUSIONS: WWC2-AS1 was highly expressed in RIF, may function as a ceRNA in the regulation of FGF2 by binding miR-16. Targeting WWC2-AS1 thus may benefit radiation-induced fibrosis treatment.

Predicting the pathological response to chemoradiotherapy of non-mucinous rectal cancer using pretreatment texture features based on intravoxel incoherent motion diffusion-weighted imaging.

OBJECTIVES: To investigate the performance of the mean parametric values and texture features based on intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) on identifying pathological complete response (pCR) to neoadjuvant chemoradiotherapy (nCRT) in locally advanced rectal cancer (LARC). METHODS: Pretreatment IVIM-DWI was performed on 41 LARC patients receiving nCRT in this prospective study. The values of IVIM-DWI parameters (apparent diffusion coefficient, ADC; pure diffusion coefficient, D; pseudo-diffusion coefficient, D* and perfusion fraction, f), the first-order, and gray-level co-occurrence matrix (GLCM) texture features were compared between the pCR (n = 9) and non-pathological responder (non-pCR, n = 32) groups. Receiver operating characteristic (ROC) curves in univariate and multivariate logistic regression analysis were generated to determine the efficiency for identifying pCR. RESULTS: The values of IVIM-DWI parameters and first-order texture features did not show significant differences between the pCR and non-pCR groups. The pCR group had lower Contrast and DifVarnc values extracted from the ADC, D, and D* maps, respectively, as well as lower CorrelatD value. Higher CorrelatD*, Correlatf, SumAvergADC, and SumAvergD values were observed in the pCR group. The area under the ROC curve (AUC) values for the individual predictors in univariate analysis ranged from 0.698 to 0.837, with sensitivities from 43.75% to 87.50% and specificities from 66.67 to 100.00%. In multivariate analysis, CorrelatD* (P < 0.001), DifVarncADC (P = 0.024), and DifVarncD (P < 0.001) were the independent predictors to pCR, with an AUC of 0.986, a sensitivity of 93.75%, and a specificity of 100.00%. CONCLUSION: Pretreatment GLCM analysis based on IVIM-DWI may be a potential approach to identify the pathological response of LARC.

The Involvement of NF-κB/Klotho Signaling in Colorectal Cancer Cell Survival and Invasion.

Lipopolysaccharide significantly increased invasion, cell proliferation, and phospho-NF-κB p65 and phospho-IGF-1R protein, but decreased klotho protein expression, cell apoptosis, and the percentage of sub G0/G1 cells in SW480 and HT29 colorectal cancer cells. In contrast, NF-κB inhibitor exhibited a counteract effect of lipopolysaccharide. Transfection of Toll-like receptor 4 shRNA significantly decreased phospho-NF-κB p65 and phospho-IGF-1R protein levels, invasion, but significantly increased klotho protein expression, cell apoptosis, and the percentage of sub G0/G1 in SW480 and HT29 cells. In conclusion, inflammation inhibits klotho gene expression in colorectal cancer cells through activation of Toll-like receptor 4 /NF-κB signal pathway.

LncRNAs regulate the cytoskeleton and related Rho/ROCK signaling in cancer metastasis.

Some of the key steps in cancer metastasis are the migration and invasion of tumor cells; these processes require rearrangement of the cytoskeleton. Actin filaments, microtubules, and intermediate filaments involved in the formation of cytoskeletal structures, such as stress fibers and pseudopodia, promote the invasion and metastasis of tumor cells. Therefore, it is important to explore the mechanisms underlying cytoskeletal regulation. The ras homolog family (Rho) and Rho-associated coiled-coil containing protein serine/threonine kinase (ROCK) signaling pathway is involved in the regulation of the cytoskeleton. Moreover, long noncoding RNAs (lncRNAs) have essential roles in tumor migration and guide gene regulation during cancer progression. LncRNAs can regulate the cytoskeleton directly or may influence the cytoskeleton via Rho/ROCK signaling during tumor migration. In this review, we focus on the regulatory association between lncRNAs and the cytoskeleton and discuss the pathways and mechanisms involved in the regulation of cancer metastasis.

NF-κB-induced WIP1 expression promotes colorectal cancer cell proliferation through mTOR signaling.

Colorectal cancer (CRC) is one of the major causes of cancer deaths worldwide. Wild-type p53-induced protein 1 (WIP1) is overexpressed in multiple human cancers and acted as an oncogene. This study was aimed to investigate the effect of WIP1 in colorectal cancer growth and analyzed underlying mechanisms. Herein, we determined WIP1 expression in CRC tissues and cell lines, as well as evaluated its detailed function in CRC cell proliferation. Several factors have been reported to mediate WIP1 effects; herein, we examined the involvement of mTOR and p21 in WIP1 regulation of CRC cell proliferation. Moreover, NF-κB has been regarded as a positive transcriptional regulator of WIP1 to activate its expression. NF-κB knockdown suppressed CRC cell proliferation, which could be reversed by WIP1 overexpression, through p21 and mTOR. Further, we examined the binding of NF-κB to the promoter region of WIP1. In CRC tissues, NF-κB expression was significantly up-regulated, and positively correlated with WIP1 expression, suggesting that inhibiting NF-κB expression to attenuate its activating effect on WIP1 expression presented a promising strategy of controlling excess proliferation of CRC cell. In summary, WIP1 promotes CRC proliferation through p21 and mTOR, both downstream targets of p53; NF-κB served as a positive transcriptional regulator of WIP1 to activate its expression and affect its function in CRC cells. Our finding provided a novel strategy for treatment for CRC.

Overexpression of NDUFA4L2 is associated with poor prognosis in patients with colorectal cancer.

BACKGROUND: NDUFA4L2 (NADH dehydrogenase (ubiquinone) 1 alpha subcomplex, 4-like 2, also called NADH-ubiquinone oxidoreductase MLRQ subunit homologue) was clearly enriched in the mitochondrial fraction under hypoxic conditions, and immunofluorescence showed a clear colocalization of NDUFA4L2 and cytochrome c in some tumour cells. However, little study has investigated its prognostic value in colorectal cancer (CRC). METHODS: In our study, mRNA-NDUFA4L2 and protein expression were analysed in 150 cases of CRC and adjacent normal tissues using immunohistochemistry, semi-quantitative reverse transcriptase-polymerase chain reaction. The correlation between NDUFA4L2 expression and clinicopathological factors was evaluated by the Chi-square test. Overall survival of patients was analysed by the Kaplan-Meier method. RESULTS: NDUFA4L2 overexpression was observed in 84% (126/150) of CRC tissues, but only in 24.7% (37/150) of adjacent normal tissues (P < 0.05). Semi-quantitative reverse transcriptase-polymerase chain reaction showed average mRNA expression levels to be 23.34 ± 1.356 and 4.34 ± 1.132 for CRC tissue and adjacent normal tissue (P < 0.05). Statistical analysis showed a significant correlation of NDUFA4L2 expression with histological grade, Dukes' stages, lymph node metastasis and liver metastasis. More importantly, multivariate analysis indicated that overexpression of NDUFA4L2 was an independent prognostic factor for CRC patients (P = 0.002). NDUFA4L2-negative patients had a higher tumour-free/overall survival rate than patients with high NDUFA4L2 expression (P = 0.001 and 0.002, respectively). CONCLUSIONS: Our data suggest that NDUFA4L2 overexpression is associated with tumour progression and a poor prognosis in CRC patients.

MicroRNA-1246 promotes growth and metastasis of colorectal cancer cells involving CCNG2 reduction.

Colorectal cancer (CRC) is the third most common cancer type and the fourth leading cause of cancer­associated mortality worldwide. MicroRNA (miR)­1246 is involved in differentiation, invasion, metastasis and chemoresistance of certain types of tumor cells. CCNG2 encodes an unconventional cyclin homolog, cyclin G2 (CycG2), associated with growth inhibition, which correlated significantly with lymph node metastasis, clinical stage, histological grade and poor overall survival in numerous cancer types. To investigate the regulation of miR­1246 on CycG2 expression, and their effects on proliferation and metastasis of CRC, HCT­116 and LOVO cells were transfected with pre­miR­1246 anti­miR­1246 and their negative controls. It was demonstrated that the expression of miR­1246 was significantly increased in CRC tissues and cell lines, which was the opposite of CycG2. miR­1246 negatively regulated the expression of CycG2 in HCT­116 and LOVO CRC cells. CCNG2 is a direct target of miR­1246 in CRC cells. Overexpression of miR­1246 induced cell proliferation, migration and invasion, while knockdown of miR­1246 inhibited proliferation, migration and invasion in the CRC cells. Upregulation of miR­1246 mediated the malignant progression of CRC and is partly attributed to the downregulation of the expression of CycG2. Consequently, these findings provided a molecular basis for the role of miR­1246/CCNG2 in the progression of human CRC and suggested a novel target for the treatment of CRC.

Side-to-Side Jejunoileal Bypass Induces Better Glucose-Lowering Effect than End-to-Side Jejunoileal Bypass on Nonobese Diabetic Rats.

BACKGROUND: Jejunoileal bypass (JIB) can markedly ameliorate diabetes in obese patients and rodents. The aim of this study is to systematically evaluate the role of the operational manner and the retained distal small bowel length in mediating changes in glucose homeostasis after intestinal bypass surgeries in nonobese diabetic rats. METHODS: Streptozotocin-induced diabetic rats underwent side-to-side jejunoileal bypass plus proximal loop ligation (SSJIBL), end-to-side jejunoileal bypass (ESJIB), proximal small bowel resection (PBR), and sham operation. Each operational manner included two subgroups, in which 30 cm (L-30) or 40 cm (L-40) distal small bowel was retained. Main outcome measures were fasting blood glucose levels (FBG), insulin sensitivity, serum insulin, glucagon-like peptide-1 (GLP-1), bilirubin (BIL), and total bile acids (TBA) levels. RESULTS: Global food intake in the sham group was higher than in the operation groups, and global body weight and food intake in the SSJIBL group were higher than in the ESJIB and PBR groups. Global body weight and food intake in L-40 group were higher than in L-30 group. The SSJIBL procedure induced better improvement in glucose homeostasis and insulin sensitivity than the ESJIB and PBR procedures, and L-30 group showed better antidiabetic effects than L-40 group. Serum GLP-1, BIL, and TBA levels in SSJIBL group were higher than in ESJIB and PBR groups. CONCLUSIONS: This study shows that side-to-side jejunoileal bypass induced better glucose-lowering effects than end-to-side jejunoileal bypass and proximal small bowel resection, and intestinal bypass surgery that retained shorter distal small bowel yielded better antidiabetic effects.

Angiopoietin-like protein 2 negatively regulated by microRNA-25 contributes to the malignant progression of colorectal cancer.

Angiopoietin-like protein 2 (ANGPTL2) is associated with tumor progression while dysregulation of its expression has been observed in various types of cancer. However, the expression and role of ANGPTL2 remain exclusive in colorectal cancer (CRC). In the present study, we determined the expression levels of ANGPTL2 in CRC tissues and cells. The roles of ANGPTL2 and miR-25 in the migration and invasion of CRC SW620 and HCT-116 cells were also investigated using transwell assays or scratch wound assays. The results showed that ANGPTL2 increased with metastatic progression. Increased ANGPTL2 and decreased microRNA-25 (miR-25) expression were found to coexist in CRC. The functional studies revealed that knockdown of ANGPTL2 reduced colony formation, and the invasive and migratory abilities of human CRC SW620 and HCT-116 cells. Similarly, overexpression of miR-25 resulted in reduced colony formation, invasion and migration in both cell lines. The overexpression of miR-25 led to a decreased ANGPTL2 mRNA and protein expression, whereas the downregulation of miR-25 resulted in increased ANGPTL2 mRNA and protein expression, in SW620 and HCT-116 cells. miR-25 directly targeted ANGPTL2 by binding to its 3'­UTR, as determined by the dual luciferase reporter assay. To the best of our know-ledge, the results of this study suggest for the first time that the abnormal upregulation of ANGPTL2 in CRC is associated with miR-25 downregulation. Additionally, miR-25­mediated ANGPTL2 promoted the malignant progression of CRC. The present study provides evidence supporting ANGPTL2 and miR-25 as diagnostic or therapeutic targets for CRC.

Role of endothelin A receptor in colon cancer metastasis: in vitro and in vivo evidence.

The endothelin (ET)-1/endothelin A receptor (ETAR) axis is reportedly involved in tumor cell invasion, survival, and metastasis. However, the role of ETAR in colon cancer metastasis and the underlying mechanisms have not been defined. In the present study, we assessed the role of ETAR in colon cancer metastasis in vitro and in vivo. Overexpression and knockdown of ETAR were respectively performed in SW480 and SW620 human colon cancer cells. Overexpression of ETAR in SW480 cells significantly increased cell survival against cisplatin, cell invasion, and matrix metalloproteinase (MMP)-2 expression, which was strengthened by exogenous ET-1 and abolished by selective ETAR antagonist BQ123 and phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. Knockdown of ETAR in SW620 cells markedly decreased cell survival against cisplatin, cell invasion, and MMP-2 expression, which was strengthened by BQ123 and LY294002, and partially rescued by exogenous ET-1. In a colon cancer liver metastasis mouse model, while ETAR overexpression promoted colon cancer liver metastases, ETAR knockdown markedly decreased liver metastases. In conclusion, our in vitro data demonstrate that ETAR mediates the promoting effects of ET-1 on colon cancer cell survival, invasion and MMP-2 expression by a PI3K-mediated mechanism. Our in vivo data indicate that ETAR markedly promotes colon cancer liver metastasis. This study provides direct evidence for a critical role of ETAR in colon cancer metastasis, which suggests that ETAR antagonism could benefit patients with metastatic colon cancer.

Basic transcription factor 3 is involved in gastric cancer development and progression.

AIM: To further analyse cancer involvement of basic transcription factor 3 (BTF3) after detection of its upregulation in gastric tumor samples. METHODS: BTF3 transcription rates in human gastric tumor tissue samples (n = 20) and adjacent normal tissue (n = 18) specimens as well as in the gastric cancer cell lines AGS, SGC-7901, MKN-28, MKN-45 and MGC803 were analyzed via quantitative real-time polymerase chain reaction. The effect of stable BTF3 silencing via infection with a small interfering RNA (siRNA)-BTF3 expressing lentivirus on SGC-7901 cells was measured via Western blotting analysis, proliferation assays, cell cycle and apoptosis profiling by flow cytometry as well as colony forming assays with a Cellomic Assay System. RESULTS: A significant higher expression of BTF3 mRNA was detected in tumors compared to normal gastric tissues (P < 0.01), especially in section tissues from female patients compared to male patients, and all tested gastric cancer cell lines expressed high levels of BTF3. From days 1 to 5, the relative proliferation rates of stable BTF3-siRNA transfected SGC7901 cells were 82%, 70%, 57%, 49% and 44% compared to the control, while the percentage of cells arrested in the G1 phase was significantly decreased (P = 0.000) and the percentages of cells in the S (P = 0.031) and G2/M (P = 0.027) phases were significantly increased. In addition, the colony forming tendency was significantly decreased (P = 0.014) and the apoptosis rate increased from 5.73% to 8.59% (P = 0.014) after BTF3 was silenced in SGC7901 cells. CONCLUSION: BTF3 expression is associated with enhanced cell proliferation, reduced cell cycle regulation and apoptosis and its silencing decreased colony forming and proliferation of gastric cancer cells.