Everolimus exerts anticancer effects through inhibiting the interaction of matrix metalloproteinase-7 with syndecan-2 in colon cancer cells.

Previous work showed that matrix metalloproteinase-7 (MMP-7) regulates colon cancer activities through an interaction with syndecan-2 (SDC-2) and SDC-2-derived peptide that disrupts this interaction and exhibits anticancer activity in colon cancer. Here, to identify potential anticancer agents, a library of 1,379 Food and Drug Administration (FDA)-approved drugs that interact with the MMP-7 prodomain were virtually screened by protein-ligand docking score analysis using the GalaxyDock3 program. Among five candidates selected based on their structures and total energy values for interacting with the MMP-7 prodomain, the known mechanistic target of rapamycin kinase (mTOR) inhibitor, everolimus, showed the highest binding affinity and the strongest ability to disrupt the interaction of the MMP-7 prodomain with the SDC-2 extracellular domain in vitro. Everolimus treatment of the HCT116 human colon cancer cell line did not affect the mRNA expression levels of MMP-7 and SDC-2 but reduced the adhesion of cells to MMP-7 prodomain-coated plates and the cell-surface localization of MMP-7. Thus, everolimus appears to inhibit the interaction between MMP-7 and SDC-2. Everolimus treatment of HCT116 cells also reduced their gelatin-degradation activity and anticancer activities, including colony formation. Interestingly, cells treated with sirolimus, another mTOR inhibitor, triggered less gelatin-degradation activity, suggesting that this inhibitory effect of everolimus was not due to inhibition of the mTOR pathway. Consistently, everolimus inhibited the colony-forming ability of mTOR-resistant HT29 cells. Together, these data suggest that, in addition to inhibiting mTOR signaling, everolimus exerts anticancer activity by interfering with the interaction of MMP-7 and SDC-2, and could be a useful therapeutic anticancer drug for colon cancer.NEW & NOTEWORTHY The utility of cancer therapeutics targeting the proteolytic activities of MMPs is limited because MMPs are widely distributed throughout the body and involved in many different aspects of cell functions. This work specifically targets the activation of MMP-7 through its interaction with syndecan-2. Notably, everolimus, a known mTOR inhibitor, blocked this interaction, demonstrating a novel role for everolimus in inhibiting mTOR signaling and impairing the interaction of MMP-7 with syndecan-2 in colon cancer.

Syndecan-2 enriches for hematopoietic stem cells and regulates stem cell repopulating capacity.

The discovery of novel hematopoietic stem cell (HSC) surface markers can enhance understanding of HSC identity and function. We have discovered a population of primitive bone marrow (BM) HSCs distinguished by their expression of the heparan sulfate proteoglycan Syndecan-2, which serves as both a marker and a regulator of HSC function. Syndecan-2 expression was increased 10-fold in CD150+CD48-CD34-c-Kit+Sca-1+Lineage- cells (long-term HSCs [LT-HSCs]) compared with differentiated hematopoietic cells. Isolation of BM cells based solely on syndecan-2 surface expression produced a 24-fold enrichment for LT-HSCs and sixfold enrichment for α-catulin+c-kit+ HSCs, and yielded HSCs with superior in vivo repopulating capacity compared with CD150+ cells. Competitive repopulation assays revealed the HSC frequency to be 17-fold higher in syndecan-2+CD34-KSL cells compared with syndecan-2-CD34-KSL cells and indistinguishable from CD150+CD34-KSL cells. Syndecan-2 expression also identified nearly all repopulating HSCs within the CD150+CD34-KSL population. Mechanistically, syndecan-2 regulates HSC repopulating capacity through control of expression of Cdkn1c (p57) and HSC quiescence. Loss of syndecan-2 expression caused increased HSC cell cycle entry, downregulation of Cdkn1c, and loss of HSC long-term repopulating capacity. Syndecan-2 is a novel marker of HSCs that regulates HSC repopulating capacity via control of HSC quiescence.

[Study on the application value of fecal SDC2 gene methylation detection in colorectal cancer screening of urban residents in Zengcheng District in Guangzhou City].

Objective: To investigate the application value of fecal Syndecan-2 (SDC2) gene methylated SDC2 (mSDC2) detection in colorectal cancer (CRC) screening among urban residents in Guangzhou City. Methods: A cross-sectional study was conducted in Shitan Town, Zengcheng District, Guangzhou City from July to December 2022. A community-based screening program for CRC was conducted among residents aged 40-74 years old. mSDC2 detection was employed in the participants, and those with positive results should be recommended to receive colonoscopy examination. The positive rate of mSDC2 detection, colonoscopy compliance rate, detection rate of intestinal lesions and clinicopathological characteristics were observed. The relationship between cycle threshold (CT) value of mSDC2 and intestinal lesions was explored. Further, the cost-effectiveness of screening was evaluated. Results: A total of 8 189 fecal samples were collected from 8 877 participants with the recovery rate of 92.25%. 8 048 qualified samples were enrolled in this study, consisted of 3 182 males (39.54%) and 4 866 females (60.46%), with the average age of 56 years old (40-74 years). The positive rate of mSDC2 detection was 7.99% (643/8 048), and the compliance rate of colonoscopy was 73.10% (470/643). 20 cases (4.25%) of colorectal cancer, 109 cases (23.19%) of advanced adenoma, 145 cases (30.85%) of non-advanced adenoma, 79 cases (16.81%) of polyps were detected. The detection rate of intestinal lesions was 75.11% and indicated significant differences in gender and age. 20 CRCs included 15 of stage 0-I, 4 of stage Ⅱ-Ⅲ and 1 of unknown stage. The CT value of mSDC2 was negatively correlated with the proportion of advanced colorectal neoplasms (χ2=16.063, P<0.001). The total cost of the screening was 4.339 5 million yuan, the screening benefit was 28.506 2 million yuan, and the benefit-cost ratio was 6.57. Conclusion: The CRC screening strategy of fecal mSDC2 detection combined with colonoscopy has high colonoscopy compliance and detection rate of intestinal lesions, which is conducive to the detection of early CRCs, and has good cost-effectiveness. This study suggests that this method may be applied to the general CRC screening in China and contribute to the prevention of CRC. The CT value of mSDC2 may have a certain suggestion on the malignant degree of intestinal tumors.

Correlation between Stool DNA-based SDC2 Methylation Tests Combined with Tumor Markers with Pathological Features in Colorectal Cancer.

BACKGROUND: Colorectal cancer (CRC) screening is the most efficient strategy to reduce disease-related mortality. In this study, we aimed to investigate the association of a methylation-based stool DNA test with serum protein biomarker panel (CEA, CA125, CA199, and AFP) in CSC patients and their relationship with pathological features to improve the diagnostic efficacy and applicability in CSC in the Chinese population. METHODS: In this double-blinded case-control study, we enrolled 150 participants from our hospital, including 50 CRC patients, 50 adenomas, and 50 healthy controls. We compared the cycling threshold (Ct) values of stool DNA-based SDC2 measured by quantitative methylation-specific PCR (MSP) in the three groups. We also evaluated the differences and correlation between serum concentrations of tumor biomarker and pathological features in patients with CSC, including TNM stage (I, II, III), tumor size, and lymph node metastasis. The discrimination performance of indexes was assessed using sensitivity, specificity, and the area under the receiver operating characteristic curve (AUC). RESULTS: CSC was more common in middle-aged people and men. The methylation-based stool DNA test was not significantly correlated with other tumor indicators except CEA, and the difference was statistically significant. Compared with the normal control group, the combined diagnostic value of the methylation-based stool DNA test and tumor indicators was significantly higher than individual biomarkers alone, especially the methylation-based stool DNA test combined with CEA and AFP, which improved the AUC to 0.96. This combination can increase the positive rate of pathological stage diagnosis. CONCLUSIONS: Combining a methylation-based stool DNA test with CEA and AFP can significantly improve the diagnostic value of CRC and can be used to confirm the diagnosis of colorectal cancer. This combination can also be used as a reliable indicator identifying early-stage CRC patients and pathology. A large-scale study is underway to further define the clinical application of this method for the diagnosis of CRC among Chinese populations.

A simplified multiplex methylated DNA testing for early detection of colorectal cancer in stool DNA.

BACKGROUND: ColoDefense1.0 assay has demonstrated its excellent sensitivity and specificity for early detection of colorectal cancer (CRC) by detecting the methylation levels of SDC2 and SEPT9, while exhibited limitations on relatively large sample capacity required and limited detection throughput by applying triplicate PCR reactions for each sample. In this study, ColoDefense1.0 was simplified and optimized into ColoDefense2.0 in a single PCR reaction. METHODS: A total 529 stool specimens were collected, and 244 CRC patients, 34 patients with advanced adenomas (AA), 64 with small polyps (SP) and 187 control subjects were divided in training and validation cohorts. Methylation levels of SEPT9 and SDC2 were examined by qPCR reactions in triplicate or single. RESULTS: The stool DNA quantity stored in preservative buffer at 37 °C up to 7 days exhibited no significant decrease. In the training cohort, when the number of replicates reduced from 3 to 1, the overall performance of ColoDefense2.0 was identical to that of ColoDefense1.0, showing sensitivities of 71.4% for AA and 90.8% for all stage CRC with a specificity of 92.9%. In the validation cohort, sensitivities of SP, AA and CRC using ColoDefense2.0 were 25.0%, 55.0% and 88.2%, increased from 14.1% (20.3%), 40.0% (40.0%) and 79.4% (67.6%) using SDC2 (SEPT9) alone; along with an overall specificity of 90.2%, decreased from 94.1% (95.1%) using SDC2 (SEPT9) alone. CONCLUSION: The simplified ColoDefense test maintained the overall performance while reduced the number of PCR reactions to 1/3, and provided an effective and convenient tool to detect early CRC and precancerous lesions and potentially improve the compliance of screening.

Diagnostic accuracy of DNA-based SDC2 methylation test in colorectal cancer screening: a meta-analysis.

BACKGROUND: A growing body of research suggests that methylated genes can be used as early diagnostic markers for cancer. Some studies on methylated Syndecan 2 (SDC2) have shown that it has a great diagnostic ability in colorectal cancer. This meta-analysis was aimed to estimate the diagnostic performance of methylated SDC2 as a potential novel biomarker to screen for the colorectal cancer. METHODS: Two independent researchers conducted a comprehensive literature search to identify all relevant studies on SDC2 methylation for the diagnosis of colorectal cancer from inception to March 1, 2021. By using STATA and Revman software, the data were analyzed using a Bivariate mixed model. The quality of each study was also evaluated. RESULTS: A total of 12 studies comprised of 1574 colorectal cancer patients and 1945 healthy people were included in our meta-analysis. Bivariate analysis showed a pooled sensitivity of 0.81 [95% confidence interval (CI) 0.74-0.86], specificity of 0.95 (95% CI 0.93-0.96), positive likelihood ratio of 15.29 (95% CI 10.83-21.60), and negative likelihood ratio of 0.21 (95% CI 0.15-0.27). The diagnostic odds ratio and the area under the summary ROC curve for diagnosing colorectal cancer were 74.42 (95% CI45.44-121.89) and 0.96 (95% CI 0.94-0.97), respectively. For adenomas, the pooled sensitivity and specificity were 0.47 (95% CI 0.34-0.61) and 0.95 (95% CI 0.92-0.97), respectively. CONCLUSIONS: Our analysis revealed that methylated SDC2 could be considered as a potential novel biomarker to screen for colorectal cancer.

The methylation of SDC2 and TFPI2 defined three methylator phenotypes of colorectal cancer.

BACKGROUND: Methylated SDC2 and TFPI2 are widely used for colorectal cancer (CRC) detection. However, they often miss some CRCs, which directly diminishes the sensitivity. Further investigations of the underlying mechanisms leading to the missed samples will facilitate developing more eligible methylation markers. METHODS: CRC samples from TCGA and GEO datasets were divided into three groups, High-methylation/ High-methylation (HH), High-methylation/Low-methylation (HL), and Low-methylation/Low-methylation (LL) according to the methylation status of SDC2 and TFPI2 promoters. Variations in age, tumor location and microsatellite instable were then assessed between the three groups and verified in our custom cohort. RESULTS: Samples of HL group preferred to derive from left-sided CRCs (P < 0.05). HH samples showed the highest microsatellite instability and mutation load (mean nonsynonymous mutations for HH/HL/LL: 10.55/3.91/7.02, P = 0.0055). Almost all mutations of BRAF, one of the five typical CpG island methylator phenotype (CIMP) related genes, were observed in HH group (HH/HL/LL: 51/0/1, P = 0.018). Besides, older patients were frequently found in HH group. Expression analysis identified 37, 84, and 22 group-specific differentially expressed genes (DEGs) for HH, HL, and LL, respectively. Functional enrichment analysis revealed that HH-specific DEGs were mainly related to transcription regulation, while LL-specific DEGs were enriched in the biological processes of extracellular matrix interaction and cell migration. CONCLUSIONS: The current study revealed that the performance of methylation-based markers might be affected by tumor location, patient age, mutation load and MSI, and these respective sides should be considered when developing new methylation markers for CRC detection.

A novel method for early detection of colorectal cancer based on detection of methylation of two fragments of syndecan-2 (SDC2) in stool DNA.

BACKGROUND: Methylated SDC2 has been proved as a diagnostic marker for human colorectal cancer (CRC), noninvasive stool DNA-based methylation testing also emerges as a novel approach for detecting CRC. The aim of this study was to evaluate the clinical performance of stool DNA-based SDC2 methylation test by a new qPCR detection reagent for early detection of CRC. METHODS: A new qPCR detection reagent contained two differentially methylated regions in SDC2 CpG islands for the detection of CRC was used in this study. Performance of the SDC2 methylation detection reagent was evaluated by analyzing limit of detection, precision, and specificity. The effect of interfering substances on assay performance was also tested. 339 subjects (102 CRC patients, 50 patients with advanced adenomas, 39 patients with non-advanced adenomas, 18 colitis patients and 130 normal individuals) from the China-Japan Friendship Hospital were evaluated. Approximately 2.5 g of stool sample was collected from each participant. Stool DNA was extracted and bisulfite-converted, followed by qPCR assay, which contained two pairs of primers for the methylation detection of two fragments of the SDC2 gene (named SDC2-A and SDC2-B). The diagnostic value of this test in CRC was evaluated by calculating receiver operating characteristic (ROC) curve, and value of the area under the curve (AUC). RESULTS: The test kit was able to detect methylated SDC2 in stool DNA samples with concentrations as low as 90 copies/µL in 100% of replicates. The sensitivity for detecting CRC by methylated SDC2-A alone was 85.29% (95% CI 77.03-91.00%) with a specificity of 96.15% (95% CI 91.08-98.58%). The sensitivity by methylated SDC2-B alone was 83.33% (95% CI 74.82-89.42%) with a specificity of 97.69% (95% CI 93.14-99.51%). However, when methylated SDC2-A and methylated SDC2-B were combined, the sensitivity for CRC detection improved to 87.25% (95% CI 79.27-92.53%) with a specificity of 94.62% (95% CI 89.11-97.56%). Further, the detection reagent achieved ROC-AUC 0.874 (95% CI 0.822-0.927) for SDC2-A, 0.906 (95% CI 0.859-0.952) for SDC2-B, and 0.939 (95% CI 0.902-0.977) for SDC2-Combine A&B. CONCLUSIONS: This study validated the capability of stool DNA-based SDC2 methylation test for early screening of CRC, and combined detection of two fragments of SDC2 gene could improve detection sensitivity.

Evaluation of combined detection of multigene mutation and SDC2/SFRP2 methylation in stool specimens for colorectal cancer early diagnosis.

PURPOSE: Molecular diagnostics of colorectal cancer (CRC) can be used as an auxiliary approach for patients recommended for colonoscopy, providing more CRC supplemental diagnosis options. This study investigated whether combined detection of KRAS/BRAF/APC mutation and SDC2/SFRP2 methylation can serve as auxiliary diagnostics in clinical management. METHODS: KRAS/BRAF/APC mutation and SDC2/SFRP2 methylation in stool samples from healthy donors, patients with CRC, advanced adenoma (AA), non-advanced adenoma (NAA), or other gastroenterological diseases were evaluated using quantitative PCR (qPCR) or methylation-specific quantitative PCR (MSP). Test accuracy was determined by evaluating the tests' sensitivity, specificity, positive/negative predictive value (PPV/NPV), or positive/negative likelihood ratio (PLR/NLR). RESULTS: The combined fecal KRAS/BRAF/APC mutation and SFRP2/SDC2 methylation detection test achieved a sensitivity of 88.57% with a PPV of 93.64% and a PLR of 7.10 for CRC patients. In comparison, the corresponding parameters for multigene mutation were 46.67%, 92.59%, and 36.26 and 83.81%, 93.94%, and 7.47, for DNA methylation, separately. The sensitivity of the combined test, gene mutation test, and DNA methylation test approach was 75%, 28.26%, and 72.83%. Furthermore, the specificity of this approach in the NAA group was 79.49%. Meanwhile, the overall diagnostic specificity for the combined test in NAA, healthy control, and interference groups was 88.42%. In addition, the sensitivity of the combined detection method increased with the disease stage in CRC patients and elevated along with the lesion size (≥ 1 cm) in AA patients. CONCLUSION: Combined detection of fecal KRAS/BRAF/APC mutation and SFRP2/SDC2 methylation has potential application value for the auxiliary diagnosis of CRC and AA.

Downregulation of lncRNA SNHG16 inhibits vascular smooth muscle cell proliferation and migration in cerebral atherosclerosis by targeting the miR-30c-5p/SDC2 axis.

Atherosclerosis (AS) is the basic lesion underlying the occurrence and development of cerebrovascular diseases. Abnormal proliferation of vascular smooth muscle cells (VSMCs) plays a crucial role in AS. We aimed to explore the role of SNHG16 in AS and the molecular mechanism of VSMC involvement in the regulation of AS. The expression levels of SNHG16, miR-30c-5p and SDC2 were detected by qRT-PCR. CCK-8, wound healing and Transwell assays were used to assess ox-LDL-induced VSMC proliferation, migration, and invasion, respectively. Western blot analysis was used to detect SDC2 and MEK/ERK pathway-related protein levels. A dual-luciferase reporter assay confirmed the binding of SNHG16 with miR-30c-5p and miR-30c-5p with SDC2. SNHG16 and SDC2 expression was upregulated in patients with AS and ox-LDL-induced VSMCs, while miR-30c-5p was downregulated. Ox-LDL-induced VSMC proliferation and migration were increased, and the MEK/ERK signalling pathway was activated. MiR-30c-5p was targeted to SNHG16 and SDC2. Downregulating SNHG16 or upregulating miR-30c-5p inhibited ox-LDL-induced VSMC proliferation and migration and inhibited MEK/ERK signalling pathway activation. In contrast, downregulating miR-30c-5p or upregulating SDC2 reversed the effects of downregulating SNHG16 or upregulating miR-30c-5p. Furthermore, downregulating SDC2 inhibited ox-LDL-induced proliferation and migration of VSMCs and inhibited activation of the MEK/ERK signalling pathway, while upregulating lncRNA SNHG16 reversed the effects of downregulating SDC2. Downregulation of SNHG16 inhibited VSMC proliferation and migration in AS by targeting the miR-30c-5p/SDC2 axis. This study provides a possible therapeutic approach to AS.

[Application study of stool-based methylated SDC2 test in the screening of colorectal neoplasms for physical examination population].

Objective: To investigate the value of stool-based methylated SDC2 test in physical examination population for the screening of colorectal neoplasms. Methods: Using the prospective cohort study method, from December 2020 to November 2021, 2 107 participants from the First People's Hospital of Xiushui County, Jiangxi Province were enrolled, consisted of 1 012 males and 1 094 females, aged 20-90 years with the median age of 49 years old. Fresh stool samples were collected and SDC2 DNA methylation tests were carried out as the primary screening method. The participants with positive results were recommended to undergo colonoscopy, and those who were negative were followed up by telephone. The positive rate of screening, the compliance of colonoscopy, and the detection of colorectal lesions were analyzed by chi-square test. Combined the follow-up results of negative subjects, the value of SDC2 DNA methylation test for the screening of colorectal neoplasms was evaluated. Results: Among the 2 107 participants, 2 106 completed the SDC2 methylation test. 113 participants (5.4%) were positive. The positive rate of primary screening increased with age significantly (χ2=32.135, P<0.001). Out of 113 cases, 72 (63.7%) underwent colonoscopy examinations. Finally, 3 (4.2%) cases of colorectal cancer, 12 (16.7%) cases of advanced adenoma, 31 (43.1%) cases of non-advanced adenoma, and 16 (22.2%) cases of non-adenomatous polyp were detected. The positive predictive value (PPV) of stool-based SDC2 DNA methylation test for intestinal lesions and colorectal neoplasms were 86.1% and 63.9%, respectively. Among the 1 374 follow-up participants, the negative predictive value (NPV) of this test for intestinal lesions and colorectal neoplasms were 97.7% and 99.4%, respectively. Conclusion: Primary stool-based SDC2 DNA methylation test and subsequent colonoscopy examination can effectively find colorectal neoplasms. This strategy may be a potential tool for the screening of colorectal neoplasms in general risk population.

Colorectal cancer screening using a stool DNA-based SDC2 methylation test: a multicenter, prospective trial.

BACKGROUND: Prevention and early detection of colorectal cancer (CRC) is a global priority, with many countries conducting population-based CRC screening programs. Although colonoscopy is the most accurate diagnostic method for early CRC detection, adherence remains low because of its invasiveness and the need for extensive bowel preparation. Non-invasive fecal occult blood tests or fecal immunochemical tests are available; however, their sensitivity is relatively low. Syndecan-2 (SDC2) is a stool-based DNA methylation marker used for early detection of CRC. Using the EarlyTect™-Colon Cancer test, the sensitivity and specificity of SDC2 methylation in stool DNA for detecting CRC were previously demonstrated to be greater than 90%. Therefore, a larger trial to validate its use for CRC screening in asymptomatic populations is now required. METHODS: All participants will collect their stool (at least 20 g) before undergoing screening colonoscopy. The samples will be sent to a central laboratory for analysis. Stool DNA will be isolated using a GT Stool DNA Extraction kit, according to the manufacturer's protocol. Before performing the methylation test, stool DNA (2 µg per reaction) will be treated with bisulfite, according to manufacturer's instructions. SDC2 and COL2A1 control reactions will be performed in a single tube. The SDC2 methylation test will be performed using an AB 7500 Fast Real-time PCR system. CT values will be calculated using the 7500 software accompanying the instrument. Results from the EarlyTect™-Colon Cancer test will be compared against those obtained from colonoscopy and any corresponding diagnostic histopathology from clinically significant biopsied or subsequently excised lesions. Based on these results, participants will be divided into three groups: CRC, polyp, and negative. The following clinical data will be recorded for the participants: sex, age, colonoscopy results, and clinical stage (for CRC cases). DISCUSSION: This trial investigates the clinical performance of a device that allows quantitative detection of a single DNA marker, SDC2 methylation, in human stool DNA in asymptomatic populations. The results of this trial are expected to be beneficial for CRC screening and may help make colonoscopy a selective procedure used only in populations with a high risk of CRC. TRIAL REGISTRATION: This trial (NCT04304131) was registered at ClinicalTrials.gov on March 11, 2020 and is available at https://clinicaltrials.gov/ct2/show/NCT04304131?cond=NCT04304131&draw=2&rank=1 .

Syndecan-2, negatively regulated by miR-20b-5p, contributes to 5-fluorouracil resistance of colorectal cancer cells via the JNK/ERK signaling pathway.

5-Fluorouracil (5-FU) resistance has been long considered as an obstacle to the efficacy of chemotherapy in colorectal cancer (CRC). In this study, we demonstrated the role of miR-20b-5p-regulated syndecan-2 (SDC2) in 5-FU resistance of CRC cells. 5-FU-resistant SW480 CRC cells were established by treatment of SW480 cells with stepwise increase of 5-FU concentration. The results showed that SDC2 was expressed significantly higher in SW480/5-FU cells than in SW480/WT cells as revealed by quantitative real-time polymerase chain reaction and western blot analysis. MTT assay and BrdU assay showed that SDC2 overexpression led to increased cell survival rate, while SDC2 knockdown reversed the drug resistance of SW480/5-FU cells. Wound healing and transwell invasion assays revealed that knockdown of SDC2 inhibited the migratory and invasive ability of SW480/5-FU cells. Moreover, animal experiments indicated that si-SDC2 plays a suppressive role in tumor growth in vivo. We also confirmed that miR-20b-5p interacted with SDC2, which reversed the effect of SDC2 in SW480/5-FU cells via the c-Jun N-terminal kinase (JNK)/extracellular regulated protein kinases (ERK) signaling pathway. These findings showed that JNK/ERK signaling pathway is involved in miR-20b-5p/SDC2 axis-mediated 5-FU resistance in SW480/5-FU cells, indicating that the miR-20b-5p/SDC2 axis is a potential target for reversing 5-FU resistance in CRC.

Molecular insights and immune responses of big belly seahorse syndecan-2 (CD362): Involvement of ectodomain in regulating cell survival, proliferation, and wound healing.

Syndecan-2, also known as CD362, is a transmembrane heparan sulfate proteoglycan which regulates cell growth, proliferation, cell adhesion, wound healing, and recruits immune cells. In the present study, we performed bioinformatics, spatial and temporal expression analyses of Hippocampus abdominalis syndecan-2 (HaSDC-2). Additionally, functional assays were conducted. HaSDC-2 has five major domains; an extracellular heparan sulfate attachment domain, a co-receptor binding domain, a transmembrane domain, two conserved domains (C1 domain, C2 domain), and a variable (V) domain. The ectodomain contained a signal peptide and GAG attachment sites. In-silico analysis revealed that HaSDC-2 contained a 798 bp long ORF and protein sequence of 265 amino acid residues. Further analysis of the amino acid sequence predicted a 28.9 kDa molecular weight and a 4.13 theoretical isoelectric point. The spatial expression of HaSDC-2 was ubiquitous in all tested tissues. HaSDC-2 expression in the liver was upregulated 24 h post-injection in response to all stimuli. Further, HaSDC-2 expression in blood cells was upregulated at 12 and 72 h post-injection in response to all the stimuli. HaSDC-2 + pcDNA™3.1(+) transfected cells exhibited significant survival in response to cell stressors such as H2O2 and HED. The ectodomain of recombinant HaSDC-2 treated cells showed significant cell proliferation in a concentration-dependent manner. The scratch wound healing assay showed significant Δ gap closures with increasing concentrations of HaSDC-2. Collectively, these results indicated that syndecan-2 was involved in regulating immune responses and cell stress conditions.

A systematic evaluation of stool DNA preparation protocols for colorectal cancer screening via analysis of DNA methylation biomarkers.

Objectives: Colorectal cancer (CRC) screening using stool samples is now in routine use where tumor DNA methylation analysis for leading markers such as NDRG4 and SDC2 is an integral part of the test. However, processing stool samples for reproducible and efficient extraction of human genomic DNA remains a bottleneck for further research into better biomarkers and assays. Methods: We systematically evaluated several factors involved in the processing of stool samples and extraction of DNA. These factors include: stool processing (solid and homogenized samples), preparation of DNA from supernatant and pellets, and DNA extraction with column and magnetic beads-based methods. Furthermore, SDC2 and NDRG4 methylation levels were used to evaluate the clinical performance of the optimal protocol. Results: The yield of total and human genomic DNA (hgDNA) was not reproducible when solid stool scraping is used, possibly due to sampling variations. More reproducible results were obtained from homogenized stool samples. Magnetic beads-based DNA extraction using the supernatant from the homogenized stool was chosen for further analysis due to better reproducibility, higher hgDNA yield, lower non-hgDNA background, and the potential for automation. With this protocol, a combination of SDC2 and NDRG4 methylation signals with a linear regression model achieved a sensitivity and specificity of 81.82 and 93.75%, respectively. Conclusions: Through the systematic evaluation of different stool processing and DNA extraction methods, we established a reproducible protocol for analyzing tumor DNA methylation markers in stool samples for colorectal cancer screening.

Proteomic profile of TGF-ß1 treated lung fibroblasts identifies novel markers of activated fibroblasts in the silica exposed rat lung.

We performed liquid chromatography-tandem mass spectrometry (LC-MS/MS) on control and TGF-ß1-exposed rat lung fibroblasts to identify proteins differentially expressed between cell populations. A total of 196 proteins were found to be differentially expressed in response to TGF-ß1 treatment. Guided by these results, we next determined whether similar changes in protein expression were detectable in the rat lung after chronic exposure to silica dust. Of the five proteins selected for further analysis, we found that levels of all proteins were markedly increased in the silica-exposed rat lung, including the proteins for the very low density lipoprotein receptor (VLDLR) and the transmembrane (type I) heparin sulfate proteoglycan called syndecan 2 (SDC2). Because VLDLR and SDC2 have not, to our knowledge, been previously linked to the pathobiology of silicosis, we next examined whether knockdown of either gene altered responses to TGF-ß1 in MRC-5 lung fibroblasts. Interestingly, we found knockdown of either VLDLR or SDC2 dramatically reduced collagen production to TGF-ß1, suggesting that both proteins might play a novel role in myofibroblast biology and pathogenesis of silica-induced pulmonary fibrosis. In summary, our findings suggest that performing LC-MS/MS on TGF-ß1 stimulated lung fibroblasts can uncover novel molecular targets of activated myofibroblasts in silica-exposed lung.

The melanocortin-1 receptor reversely regulates the melanin synthesis and migration of melanoma cells via dimerization-induced conformational changes.

We previously reported that the melanocortin-1 receptor (MC1R), a key regulator of melanogenesis, regulates cell migration; however, the detailed mechanism remained unknown. Since the homo-dimerization of MC1R by four inter-subunit disulfide bonds is known to be functionally important for melanogenesis, we investigated the importance of MC1R dimerization for cell migration. Unlike the wild-type MC1R, the dimerization-defective mutant MC1R in which four critical Cys residues were replaced with Ala residues (Cys35-267-273-275Ala) significantly inhibited melanin synthesis but enhanced cell migration in human MNT-1 and A375 melanoma cells. This suggests that there may be a reverse correlation between melanin synthesis and cell migration. Interestingly, melanoma cells expressing the dimerization-defective mutant exhibited enhanced expression of the cell surface heparan sulfate proteoglycan, syndecan-2, and knockdown of syndecan-2 expression decreased the mutant-mediated cell migration. Consistently, ASIP, an antagonist of MC1R, enhanced syndecan-2 expression and cell migration and reversed the α-melanocyte-stimulating hormone (α-MSH)-mediated inhibition of syndecan-2 expression. Furthermore, α-MSH reduced the cell migration of MNT1 cells expressing wild-type MC1R but not its dimerization-defective mutant. Together, these data strongly suggest that MC1R reversely regulates melanin synthesis and migration via the conformational changes induced by dimerization.

Syndecan-2 Attenuates Radiation-induced Pulmonary Fibrosis and Inhibits Fibroblast Activation by Regulating PI3K/Akt/ROCK Pathway via CD148.

Radiation-induced pulmonary fibrosis is a severe complication of patients treated with thoracic irradiation. We have previously shown that syndecan-2 reduces fibrosis by exerting alveolar epithelial cytoprotective effects. Here, we investigate whether syndecan-2 attenuates radiation-induced pulmonary fibrosis by inhibiting fibroblast activation. C57BL/6 wild-type mice and transgenic mice that overexpress human syndecan-2 in alveolar macrophages were exposed to 14 Gy whole-thoracic radiation. At 24 weeks after irradiation, lungs were collected for histological, protein, and mRNA evaluation of pulmonary fibrosis, profibrotic gene expression, and α-smooth muscle actin (α-SMA) expression. Mouse lung fibroblasts were activated with transforming growth factor (TGF)-ß1 in the presence or absence of syndecan-2. Cell proliferation, migration, and gel contraction were assessed at different time points. Irradiation resulted in significantly increased mortality and pulmonary fibrosis in wild-type mice that was associated with elevated lung expression of TGF-ß1 downstream target genes and cell death compared with irradiated syndecan-2 transgenic mice. In mouse lung fibroblasts, syndecan-2 inhibited α-SMA expression, cell contraction, proliferation, and migration induced by TGF-ß1. Syndecan-2 attenuated phosphoinositide 3-kinase/serine/threonine kinase/Rho-associated coiled-coil kinase signaling and serum response factor binding to the α-SMA promoter. Syndecan-2 attenuates pulmonary fibrosis in mice exposed to radiation and inhibits TGF-ß1-induced fibroblast-myofibroblast differentiation, migration, and proliferation by down-regulating phosphoinositide 3-kinase/serine/threonine kinase/Rho-associated coiled-coil kinase signaling and blocking serum response factor binding to the α-SMA promoter via CD148. These findings suggest that syndecan-2 has potential as an antifibrotic therapy in radiation-induced lung fibrosis.

Syndecan-2 cytoplasmic domain up-regulates matrix metalloproteinase-7 expression via the protein kinase Cγ-mediated FAK/ERK signaling pathway in colon cancer.

The syndecan family of heparan sulfate proteoglycans contributes to cell adhesion and communication by serving as co-receptors for cell signaling and extracellular matrix molecules. Syndecan-2 is located at the cell surface, and we previously reported that it induces matrix metalloproteinase-7 (MMP-7) expression in colon cancer cells. However, the underlying regulatory mechanisms are unknown. Here, we report that overexpression of syndecan-2 in HT-29 colon cancer cells increases the phosphorylation of focal adhesion kinase (FAK) and ERK in parallel with up-regulated MMP-7 expression, but a syndecan-2 mutant lacking the cytoplasmic domain showed significant reductions in these effects. Consistent with this observation, FAK inhibition via FAK-related non-kinase expression or inhibition of ERK with the ERK1/2 inhibitor SCH772984 diminished the syndecan-2-mediated up-regulation of MMP-7. Activation of PKC enhanced syndecan-2-mediated MMP-7 expression, whereas inhibition of PKC had the opposite effect. Of note, the exogenous expression of syndecan-2 triggered localization of PKCγ to the membrane. Expression of syndecan-2 harboring a phosphomimetic (S198E) mutation of the variable region of the cytoplasmic domain enhanced MMP-7 expression and FAK phosphorylation. Finally, experimental suppression of shedding of the syndecan-2 extracellular domain did not significantly affect the syndecan-2-mediated up-regulation of MMP-7 in the early period after syndecan-2 overexpression. Taken together, these findings suggest that syndecan-2's cytoplasmic domain up-regulates MMP-7 expression in colon cancer cells via PKCγ-mediated activation of FAK/ERK signaling.