Reconstitution of TGFBR2 in HCT116 colorectal cancer cells causes increased LFNG expression and enhanced N-acetyl-d-glucosamine incorporation into Notch1

Mutual regulation between glycosylation and transforming growth factor-β isoforms signaling pathway

Transforming growth factor-beta (TGF-β) superfamily members orchestrate a wide breadth of biological processes. Through Sma and Mad (Smad)-related dependent or noncanonical pathways, TGF-β members involve in the occurrence and development of many diseases such as cancers, fibrosis, autoimmune diseases, cardiovascular diseases and brain diseases. Glycosylation is one kind of the most common posttranslational modifications on proteins or lipids. Abnormal protein glycosylation can lead to protein malfunction and biological process disorder, thereby causing serious diseases. Previously, researchers commonly make comprehensive systematic overviews on the roles of TGF-β signaling in a specific disease or biological process. In recent years, more and more evidences associate glycosylation modification with TGF-β signaling pathway, and we can no longer disengage and ignore the roles of glycosylation from TGF-β signaling to make investigation. In this review, we provide an overview of current findings involved in glycosylation within TGF-βs and theirs receptors, and the interaction effects between glycosylation and TGF-β subfamily signaling, concluding that there is an intricate mutual regulation between glycosylation and TGF-β signaling, hoping to present the glycosylation regulatory patterns that concealed in TGF-βs signaling pathways.

RNA-binding protein with serine-rich domain 1 regulates microsatellite instability of uterine corpus endometrial adenocarcinoma

OBJECTIVE

To determine the role of RNA-binding protein with serine-rich domain 1 (RNPS1) in uterine corpus endometrial carcinoma (UCEC), the role of RNPS1 knockdown in UCEC development in vitro and in vivo, and the relationship between RNPS1 and mismatch repair (MMR) in UCEC.

METHODS

We predicted the potential function of RNPS1 using bioinformatics systems. The expression of RNPS1 in tissues and cell lines was analyzed by western blotting and immunohistochemistry. The expression of RNPS1 in MMR was assessed using bioinformatics and western blotting. The proliferation and apoptosis of UCEC cells were assessed under RNPS1 knockdown conditions, and RNPS1 regulation in MMR was detected by suppressing Notch signaling. Associations between RNPS1 and gene mutations in UCEC and prognosis were analyzed.

RESULTS

The RNPS1 level was higher in UCEC tumors than in normal tissues and tumors or RL952 cells. Prognostic outcomes were worse when UCEC showed abundant RNPS1 expression. Lentiviral RNPS1 knockdown weakened tumor cell proliferation and suppressed biomarker expression, reduced the tumor volume, promoted apoptosis in vitro and in vivo, and inhibited UCEC development. Increased MutS homolog 2 (MSH2) and MutS homolog 6 (MSH6) levels in MMR after RNPS1 knockdown were reversed by inhibiting Notch signaling. Furthermore, RNPS1 was associated with mutations in NAA11, C2orf57, NUPR1, and other genes involved in UCEC prognosis.

CONCLUSION

RNPS1 may regulate the expression levels of MSH2 and MSH6 in MMR, enhancing the proliferation, development, and prognosis of UCEC through a Notch signaling pathway in UCEC. Our study offers a new method and strategy for delaying UCEC development through modulating MMR.

Impact of sialyltransferase ST6GAL1 overexpression on different colon cancer cell types

Cancer-associated glycan structures can be both tumor markers and engines of disease progression. The structure Siaα2,6Galβ1,4GlcNAc (Sia6LacNAc), synthesized by sialyltransferase ST6GAL1, is a cancer-associated glycan. Although ST6GAL1/Sia6LacNAc are often overexpressed in colorectal cancer (CRC), their biological and clinical significance remains unclear. To get insights into the clinical relevance of ST6GAL1 expression in CRC, we interrogated The Cancer Genome Atlas with mRNA expression data of hundreds of clinically characterized CRC and normal samples. We found an association of low ST6GAL1 expression with microsatellite instability (MSI), BRAF mutations and mucinous phenotype but not with stage, response to therapy and survival. To investigate the impact of ST6GAL1 expression in experimental systems, we analyzed the transcriptome and the phenotype of the CRC cell lines SW948 and SW48 after retroviral transduction with ST6GAL1 cDNA. The two cell lines display the two main pathways of CRC transformation: chromosomal instability and MSI, respectively. Constitutive ST6GAL1 expression induced much deeper transcriptomic changes in SW948 than in SW48 and affected different genes in the two cell lines. ST6GAL1 expression affected differentially the tyrosine phosphorylation induced by hepatocyte growth factor, the ability to grow in soft agar, to heal a scratch wound and to invade Matrigel in the two cell lines. These results indicate that the altered expression of a cancer-associated glycosyltransferase impacts the gene expression profile, as well as the phenotype, although in a cancer subtype-specific manner.

Transforming Growth Factor-β Signaling Pathway in Colorectal Cancer and Its Tumor Microenvironment

Transforming growth factor-beta (TGF-β) signaling is one of the important cellular pathways that play key roles for tissue maintenance. In particular, it is important in the context of inflammation and tumorigenesis by modulating cell growth, differentiation, apoptosis, and homeostasis. TGF-β receptor type 2 (TGFBR2) mutations affected by a mismatch repair deficiency causes colorectal cancers (CRCs) with microsatellite instability, which is, however, associated with relatively better survival rates. On the other hand, loss of SMAD4, a transcription factor in the TGF-β superfamily signaling, promotes tumor progression. Loss of heterozygosity on chromosome 18 can case SMAD4-deficient CRC, which results in poorer patients' survival. Such bidirectional phenomenon driven by TGF-β signaling insufficiency reflects the complexity of this signaling pathway in CRC. Moreover, recent understanding of CRC at the molecular level (consensus molecular subtype classification) provides deep insight into the important roles of TGF-β signaling in the tumor microenvironment. Here we focus on the TGF-β signaling in CRC and its interaction with the tumor microenvironment. We summarize the molecular mechanisms of CRC tumorigenesis and progression caused by disruption of TGF-β signaling by cancer epithelial cells and host stromal cells.

Transforming Growth Factor-β Signaling Pathway in Colorectal Cancer and Its Tumor Microenvironment

Transforming growth factor-beta (TGF-β) signaling is one of the important cellular pathways that play key roles for tissue maintenance. In particular, it is important in the context of inflammation and tumorigenesis by modulating cell growth, differentiation, apoptosis, and homeostasis. TGF-β receptor type 2 (TGFBR2) mutations affected by a mismatch repair deficiency causes colorectal cancers (CRCs) with microsatellite instability, which is, however, associated with relatively better survival rates. On the other hand, loss of SMAD4, a transcription factor in the TGF-β superfamily signaling, promotes tumor progression. Loss of heterozygosity on chromosome 18 can case SMAD4-deficient CRC, which results in poorer patients’ survival. Such bidirectional phenomenon driven by TGF-β signaling insufficiency reflects the complexity of this signaling pathway in CRC. Moreover, recent understanding of CRC at the molecular level (consensus molecular subtype classification) provides deep insight into the important roles of TGF-β signaling in the tumor microenvironment. Here we focus on the TGF-β signaling in CRC and its interaction with the tumor microenvironment. We summarize the molecular mechanisms of CRC tumorigenesis and progression caused by disruption of TGF-β signaling by cancer epithelial cells and host stromal cells.

TGFBR2‑dependent alterations of microRNA profiles in extracellular vesicles and parental colorectal cancer cells

In colorectal cancer (CRC) with microsatellite instability (MSI), >90% of cases are affected by inactivating frameshift mutations of transforming growth factor β receptor type 2 (TGFBR2). TGFBR2 deficiency is considered to drive MSI tumor progression by abrogating downstream TGF‑β signaling. This pathway can alter the expression of coding and non‑coding RNAs, including microRNAs (miRNAs), which are also present in extracellular vesicles (EVs) as post‑transcriptional modulators of gene expression. In our previous study, it was shown that TGFBR2 deficiency alters the protein composition and function of EVs in MSI tumors. To investigate whether mutant TGFBR2 may also affect the miRNA cargo of EVs, the present study characterized miRNAs in EVs and their parental MSI tumor cells that differed only in TGFBR2 expression status. The HCT116‑TGFBR2 MSI cell line model enables the doxycycline (dox)‑inducible reconstituted expression of TGFBR2 in an isogenic background (‑dox, TGFBR2 deficient; +dox, TGFBR2 proficient). Small RNA sequencing of cellular and EV miRNAs showed that the majority of the miRNAs (263/471; 56%) were shared between MSI tumor cells and their EVs. Exploratory data analysis revealed the TGBFR2‑dependent cluster separation of miRNA profiles in EVs and MSI tumor cells. This segregation appeared to result from two subsets of miRNAs, the expression of which were regulated in a TGFBR2‑dependent manner (EVs: n=10; MSI cells: n=15). In the EV subset, 7/10 miRNAs were downregulated and 3/10 were upregulated by TGFBR2 deficiency. In the cellular subset, 13/15 miRNAs were downregulated and 2/15 miRNAs were upregulated in the TGFBR2‑deficient cells. The present study emphasizes the general overlap of miRNA profiles in MSI tumor cells and their EVs, but also highlights the impact of a single tumor driver mutation on the expression of individual miRNAs, as exemplified by the downregulation of miR‑381‑3p in TGFBR2‑deficient MSI tumor cells and their secreted EVs.

MEIS2 promotes cell migration and invasion in colorectal cancer

Colorectal cancer (CRC) is one of the most common types of malignancy worldwide. Distant metastasis is a key cause of CRC-associated mortality. MEIS2 has been identified to be dysregulated in several types of human cancer. However, the mechanisms underlying the regulatory role of MEIS2 in CRC metastasis remain largely unknown. For the first time, the present study demonstrated that MEIS2 serves a role as a promoter of metastasis in CRC. In vivo and in vitro experiments revealed that knockdown of MEIS2 significantly suppressed CRC migration, invasion and the epithelial-mesenchymal transition. Furthermore, microarray and bioinformatics analyses were performed to investigate the underlying mechanisms of MEIS2 in the regulation of CRC metastasis. Additionally, it was identified that a high expression of MEIS2 was significantly associated with a shorter overall survival time for patients with CRC. The present study demonstrated that MEIS2 may serve as a novel biomarker for CRC.

Correlation between tripartite motif-containing protein 44 protein expression and the prognosis of postoperative patients exhibiting skin squamous cell carcinoma

Tripartite motif-containing protein 44 (TRIM44) plays an important role in the development and progression of some human cancers; however, its role in skin squamous cell carcinoma (SCC) remains unknown. The aim of the present study was to investigate TRIM44 expression and clinicopathological significance of TRIM44 in SCC.Immunohistochemistry (IHC) technique, reverse transcriptase-polymerase chain reaction (RT-PCR) and western blot were performed to evaluate differences in TRIM44 protein expression in SCC and normal skin tissues.IHC showed that the positive rate of TRIM44 staining in SCC tissues 26.00% (9/30), while the positive rate of normal control group was 83.33% (25/30). The positive rate of TRIM44 staining in SCC tissues is significantly lower than normal skin tissue (P <.01). RT-PCR showed that the positive rates of TRIM44 mRNA expression in SCC tissues were 16.67% (5/30), but the positive rate of normal control group was 86.67% (26/30). TRIM44 mRNA expression in SCC group was significantly lower than that in the normal group (P <.01). Kaplan-Meier survival analysis showed that low expression was associated with poor overall survival in SCC patients (P =.004). Multi-factor survival analysis indicated that both low TRIM44 expression and tumor stage were independent factors affecting the overall survival of patients with SCC (P =.038 and P =.001, respectively). Low expression of TRIM44 in SCC was associated with staging (P =.009 and P =.008, respectively) and metastasis (P =.003 and P =.004, respectively).The levels of TRIM44 protein and TRIM44 mRNA in SCC are both lowly expressed which is strongly associated with tumor staging, metastasis, and poor survival. And it also is an independent factor affecting the overall survival of patients with SCC.

Identification of susceptibility pathways for the role of chromosome 15q25.1 in modifying lung cancer risk

Genome-wide association studies (GWAS) identified the chromosome 15q25.1 locus as a leading susceptibility region for lung cancer. However, the pathogenic pathways, through which susceptibility SNPs within chromosome 15q25.1 affects lung cancer risk, have not been explored. We analyzed three cohorts with GWAS data consisting 42,901 individuals and lung expression quantitative trait loci (eQTL) data on 409 individuals to identify and validate the underlying pathways and to investigate the combined effect of genes from the identified susceptibility pathways. The KEGG neuroactive ligand receptor interaction pathway, two Reactome pathways, and 22 Gene Ontology terms were identified and replicated to be significantly associated with lung cancer risk, with P values less than 0.05 and FDR less than 0.1. Functional annotation of eQTL analysis results showed that the neuroactive ligand receptor interaction pathway and gated channel activity were involved in lung cancer risk. These pathways provide important insights for the etiology of lung cancer.

Associations of TGFBR1 and TGFBR2 gene polymorphisms with the risk of hypospadias: a case-control study in a Chinese population

This case-control study investigated the association of transforming growth factor-β (TGF-β) receptor type I and II (TGFBR1 and TGFBR2) gene polymorphisms with the risk of hypospadias in a Chinese population. One hundred and sixty two patients suffering from hypospadias were enrolled as case group and 165 children who underwent circumcision were recruited as control group. Single nucleotide polymorphisms (SNPs) in TGFBR1 and TGFBR2 genes were selected on the basis of genetic data obtained from HapMap. PCR-restriction fragment length polymorphism (PCR-RFLP) was performed to identify TGFBR1 and TGFBR2 gene polymorphisms and analyze genotype distribution and allele frequency. Logistic regression analysis was conducted to estimate the risk factors for hypospadias. No significant difference was found concerning the genotype and allele frequencies of TGFBR1 rs4743325 polymorphism between the case and control groups. However, genotype and allele frequencies of TGFBR2 rs6785358 in the case group were significantly different in contrast with those in the control group. Patients carrying the G allele of TGFBR2 rs6785358 polymorphism exhibited a higher risk of hypospadias compared with the patients carrying the A allele (P<0.05). The TGFBR2 rs6785358 genotype was found to be significantly related to abnormal pregnancy and preterm birth (both P<0.05). The frequency of TGFBR2 rs6785358 GG genotype exhibited significant differences amongst patients suffering from four different pathological types of hypospadias. Logistic regression analysis revealed that preterm birth, abnormal pregnancy, and TGFBR2 rs6785358 were the independent risk factors for hypospadias. Our study provides evidence that TGFBR2 rs6785358 polymorphism might be associated with the risk of hypospadias.

Predicting radiotherapy response for patients with soft tissue sarcoma by developing a molecular signature

Soft tissue sarcomas are rare and aggressive tumors arising from connective tissues. Adjuvant radiotherapy is a commonly used treatment approach for the majority of sarcomas. We attempted to identify a gene signature that can predict radiosensitive patients who are most likely to have a better treatment response from radiotherapy, compared with disease progression. Using the publicly available data of soft tissue sarcoma from The Cancer Genome Atlas, we developed a cross-validation procedure to identify a predictive gene signature for radiosensitivity. The results showed that the predicted radiosensitive patients who received radiotherapy had significantly improved treatment response. We further provide supportive evidence to validate our sensitivity prediction. Results showed that the predicted radiosensitive patients who received radiotherapy had significantly improved survival than patients who did not. ROC analysis showed that the developed gene signature had a powerful prediction on treatment response. We further found that predicted radiosensitive patients who received radiotherapy had a significantly reduced rate of new tumor events. Finally, we validated our gene signature using a hierarchical cluster analysis, and found that the predicted sensitivities were well-matched with results from the cluster analysis. These results are consistent with our expectation, suggesting that the identified gene signature and radiosensitivity prediction are effective. The genes involved in the signature may provide a molecular basis for prognostic studies and radiotherapy target discovery.

Correlation between secreted protein acidic and rich in cysteine protein expression and the prognosis of postoperative patients exhibiting esophageal squamous cell carcinoma

The aim of the present study was to investigate the association between the expression level of secreted protein acidic and rich in cysteine (SPARC) and the prognosis of postoperative patients with esophageal squamous cell carcinoma (ESCC). The expression level of SPARC was detected in the 89 ESCC tissue cases and 100 healthy esophageal mucosa cases, which served as the controls. Immunohistochemistry and reverse transcription‑polymerase chain reaction (RT‑PCR) were employed to evaluate the SPARC expression in cases with ESCC. RT‑PCR demonstrated that the positive rates of SPARC mRNA expression in ESCC were 71.91% (64/89). The positive rates of normal esophageal mucosa mRNA expression were 15.00% (15/100), which were significantly lower than that in the ESCC tissue samples. The difference was statistically significant (P<0.001). Immunohistochemical staining indicated that the positive expression rate of SPARC protein in the ESCC tissue samples was significantly higher than that in the esophageal mucosa tissue samples (65.17 vs. 8.00%; P<0.001). The expression of SPARC protein was negatively correlated with lymph node metastasis (P<0.05), which was not associated with the pathologic gross morphology, tumor differentiation degree or other clinical features. The survival of patients with ESCC was not associated with the expression level of SPARC protein (P>0.05), but was associated with the tumor location (P<0.05), differentiation (P<0.001) and staging (P<0.05). Thus, SPARC mRNA and protein were highly expressed in ESCC, and negatively correlated with lymph node metastasis, which was not associated with postoperative survival of ESCC patients. Thus, detection of SPARC mRNA and protein expression levels may facilitate early diagnosis and prognosis assessment of ESCC.

Synthesis and bioactivity of novel C2-glycosyl triazole derivatives as acetylcholinesterase inhibitors

New C2-glycosyl triazole derivatives 6a–l were synthesized by cyclization of glycosyl acylthiosemicarbazides 5 in refluxing 3 N sodium hydroxide aqueous solution. Substrates 5 were obtained by the reaction of glycosyl isothiocyanate 3 with various hydrazides. The acetylcholinesterase (AChE) inhibitory activities of compounds 6 were tested by Ellman’s method. Compounds that exhibited over 85% inhibition were subsequently evaluated for the IC50 values. Compound 6f possesses the best acetylcholinesterase-inhibition activity with IC50 of 1.46±0.25 μg/mL.

TGFBR2-dependent alterations of exosomal cargo and functions in DNA mismatch repair-deficient HCT116 colorectal cancer cells

BACKGROUND

Colorectal cancers (CRCs) that lack DNA mismatch repair function exhibit the microsatellite unstable (MSI) phenotype and are characterized by the accumulation of frameshift mutations at short repetitive DNA sequences (microsatellites). These tumors recurrently show inactivating frameshift mutations in the tumor suppressor Transforming Growth Factor Beta Receptor Type 2 (TGFBR2) thereby abrogating downstream signaling. How altered TGFBR2 signaling affects exosome-mediated communication between MSI tumor cells and their environment has not been resolved. Here, we report on molecular alterations of exosomes shed by MSI cells and the biological response evoked in recipient cells.

METHODS

Exosomes were isolated and characterized by electron microscopy, nanoparticle tracking, and western blot analysis. TGFBR2-dependent effects on the cargo and functions of exosomes were studied in a MSI CRC model cell line enabling reconstituted and inducible TGFBR2 expression and signaling. Microsatellite frameshift mutations in exosomal and cellular DNA were examined by PCR-based DNA fragment analysis and exosomal protein profiles were identified by mass spectrometry. Uptake of fluorescent-labeled exosomes by hepatoma recipient cells was monitored by confocal microscopy. TGFBR2-dependent exosomal effects on secreted cytokine levels of recipient cells were analyzed by Luminex technology and ELISA.

RESULTS

Frameshift mutation patterns in microsatellite stretches of TGFBR2 and other MSI target genes were found to be reflected in the cargo of MSI CRC-derived exosomes. At the proteome level, reconstituted TGFBR2 expression and signaling uncovered two protein subsets exclusively occurring in exosomes derived from TGFBR2-deficient (14 proteins) or TGFBR2-proficient (five proteins) MSI donor cells. Uptake of these exosomes by recipient cells caused increased secretion (2-6 fold) of specific cytokines (Interleukin-4, Stem Cell Factor, Platelet-derived Growth Factor-B), depending on the TGFBR2 expression status of the tumor cell.

CONCLUSION

Our results indicate that the coding MSI phenotype of DNA mismatch repair-deficient CRC cells is maintained in their exosomal DNA. Moreover, we uncovered that a recurrent MSI tumor driver mutation like TGFBR2 can reprogram the protein content of MSI cell-derived exosomes and in turn modulate the cytokine secretion profile of recipient cells. Apart from its diagnostic potential, these TGFBR2-dependent exosomal molecular and proteomic signatures might help to understand the signaling routes used by MSI tumors. Fricke et al. uncovered coding microsatellite instability-associated mutations of colorectal tumor driver genes like TGFBR2 in MSI tumor cellderived exosomes. Depending on the TGFBR2 expression status of their donor cells, shed exosomes show distinct proteomic signatures and promote altered cytokine secretion profiles in recipient cells.