RTK/ERK pathway under natural selection associated with prostate cancer

Effects of DDR1 on migration and adhesion of periodontal ligament cells and the underlying mechanism

BACKGROUND AND OBJECTIVE

As one of the widely expressed cell surface receptors binding to collagen, the most abundant component of the extracellular matrix (ECM), knowledge of the expression, functions, and mechanisms underlying the role of discoidin domain receptor 1 (DDR1) in human periodontal ligament cells (hPDLCs) is incomplete. This study determined the expression of DDR1 in hPDLCs and the effect of DDR1 upon migration and adhesion to hPDLCs, as well as the related regulatory mechanisms.

MATERIALS AND METHODS

The expression of DDR1 and the DDR1 isoforms in hPDLCs from six donors were tested. The migratory ability (horizontal and vertical) and adhesive capacity of hPDLCs with or without specific knockdown of DDR1 were evaluated. After treatment with MEK-ERK1/2 inhibitors (PD98059 and U0126) with or without RNAi, the migratory and adhesive capacity of hPDLCs were re-tested. Western blotting was performed to verify p-MEK1/2 and p-ERK1/2, the key factors of the MEK-ERK1/2 signaling pathways.

RESULTS

DDR1 was detected in hPDLCs in the mRNA and protein level; DDR1b was the dominant isoform. Knockdown of DDR1 almost halved the migratory capacity and significantly downregulated the adhesive capacity of hPDLCs. The use of MEK-ERK1/2 inhibitors caused declined migratory and adhesive capacity of hPDLCs as well. After DDR1 was knocked down, the expression of p-MEK and p-ERK protein declined significantly while total MEK and ERK showed no obvious change, which means the ratio of p-MEK/MEK and p-ERK/ERK was markedly reduced.

CONCLUSIONS

DDR1 plays an important role in the migration and adhesion of hPDLCs and might be regulated via the MEK-ERK1/2 signaling pathway.

Epidermal Growth Factor Receptor (EGFR) Gene Polymorphism May be a Modifier for Cadmium Kidney Toxicity

The results of many studies indicate that cadmium (Cd) exposure is harmful to humans, with the proximal tubule of the kidney being the main target of Cd accumulation and toxicity. Studies have also shown that Cd has the effect of activating the pathway of epidermal growth factor receptor (EGFR) signaling and cell growth. The EGFR is a family of transmembrane receptors, which are widely expressed in the human kidney. The aim of this study was to investigate the kidney function estimated glomerular filtration rate (eGFR), and its relationship with plasma Cd level and EGFR gene polymorphism. Using data from Academia Sinica Taiwan biobank, 489 subjects aged 30-70 years were analyzed. The demographic characteristics was determined from questionnaires, and biological sampling of urine and blood was determined from physical examination. Kidney function was assessed by the eGFR with CKD-EPI formula. Plasma Cd (ug/L) was measured by inductively coupled plasma mass spectrometry. A total of 97 single-nucleotide polymorphisms (SNPs) were identified in the EGFR on the Taiwan biobank chip, however 4 SNPs did not pass the quality control. Multiple regression analyses were performed to achieve the study aim. The mean (±SD) plasma Cd level of the study subjects was 0.02 (±0.008) ug/L. After adjusting for confounding variables, rs13244925 AA, rs6948867 AA, rs35891645 TT and rs6593214 AA types had higher eGFR (4.89 mL/min/1.73 m² (p = 0.035), 5.54 mL/min/1.73 m² (p = 0.03), 4.96 mL/min/1.73 m² (p = 0.048) and 5.16 mL/min/1.73 m² (p = 0.048), respectively). Plasma cadmium and rs845555 had an interactive effect on eGFR. In conclusion, EGFR polymorphisms could be modifiers of Cd kidney toxicity, in which rs13244925 AA, rs6948867 AA, rs35891645 TT and rs6593214 AA may be protective, and Cd interacting with rs845555 may affect kidney function.

The Association of Renal Function and Plasma Metals Modified by EGFR and TNF-α Gene Polymorphisms in Metal Industrial Workers and General Population

Exposure to metals may be associated with renal function impairment, but the effect modified by genetic polymorphisms was not considered in most studies. Epidermal growth factor receptor (EGFR) and tumor necrotic factor-α (TNF-α) play important roles in renal hemodynamics, and they have been reported to be associated with some renal diseases. The aim of our research is to explore whether genetic variations in EGFR and TNF-α have influence on renal function under exposure to various metals. This cross-sectional study consisted of 376 metal industrial workers, 396 participants of Taiwan Biobank, and 231 volunteers of health examinations. We identified 23 single nucleotide polymorphisms (SNPs) on the EGFR gene and 6 SNPs on the TNF-α gene, and we also measured their plasma concentration of cobalt, copper, zinc, selenium, arsenic, and lead. Multiple regression analysis was applied to investigate the association between various SNPs, metals, and renal function. Our results revealed some protective and susceptible genotypes under occupational or environmental exposure to metals. The individuals carrying EGFR rs2280653 GG might have declined renal function under excessive exposure to selenium, and those with EGFR rs3823585 CC, rs12671550 CC, and rs4947986 GG genotypes might be susceptible to lead nephrotoxicity. We suggest the high-risk population to prevent renal diseases.

Knockout of glucosidase II beta subunit inhibits growth and metastatic potential of lung cancer cells by inhibiting receptor tyrosine kinase activities

Glucosidase II (GluII) plays a major role in regulating post-translation modification of N-linked glycoproteins. We have previously reported that the expression of glucosidase II beta subunit (GluIIβ) was significantly increased in lung tumor tissues and its suppression triggers autophagy and/or apoptosis. Here, we investigated the role of GluIIβ in cell growth, metastatic potential, and receptor tyrosine kinases (RTKs) signaling activity in lung carcinoma cell lines. CRISPR-CAS9 technology was used to knockout the GluIIβ encoding gene (PRKSH) in lung carcinoma cells. GluIIβ knockout cells exhibited drastically slower growth rates in comparison to non-target transfected cells, particularly with lower concentrations of fetal bovine serum, indicating impairment of their ability to survive under nutritional deprivation. Cell migration and anchorage-independent growth, the fundamental components of cancer cell metastasis, were significantly decreased in GluIIβ knockout cells. Knockout of GluIIβ increased the sensitivity of lung cancer cells to cisplatin but reduced their sensitivity to gefitinib. Interestingly, knocking out of GluIIβ lowered overall RTK signaling activities to less than half of those in non-target transfected cells, which could represent a novel strategy for blocking multiple RTKs in tumor cells in an effort to improve lung cancer treatment.

The ERBB2 gene polymorphisms rs2643194, rs2934971, and rs1058808 are associated with increased risk of gastric cancer

Gastric cancer (GC) is the third most lethal type of cancer worldwide. Single nucleotide polymorphisms (SNPs) in regulatory sites or coding regions can modify the expression of genes involved in gastric carcinogenesis, as ERBB2, which encodes for the tyrosine-kinase receptor HER-2. The aim of this work was to analyze the association of the polymorphisms: rs2643194, rs2517951, rs2643195, rs2934971, and rs1058808 with GC, as they have not yet been analyzed in GC patients, as well as to report their frequency in the general Mexican population (GMP). We studied genomic DNA from subjects with GC (n=74), gastric inflammatory diseases (GID, n=76 control subjects), and GMP (n=102). Genotypes were obtained by means of real-time PCR and DNA-sequencing. The risks for GC were estimated through odds ratio (OR) using the Cochran-Armitage trend test and multinomial logistic regression. Increased risk for GC was observed under the dominant inheritance model for the rs2643194 TT or CT genotypes with an OR of 2.75 (95%CI 1.12−6.75, P=0.023); the rs2934971 TT or GT genotypes with an OR of 2.41 (95%CI 1.01−5.76, P=0.043), and the rs1058808 GG or CG genotypes with an OR of 2.21 (95%CI 1.00−4.87, P=0.046). The SNPs rs2643194, rs2934971, and rs1058808 of the ERBB2 gene were associated with increased risk for GC.

Involvement of the glutamine RF‑amide peptide and its cognate receptor GPR103 in prostate cancer

Glutamine RF‑amide peptide (QRFP) belongs to the RFamide neuropeptide family, which is involved in a wide spectrum of biological activities, ranging from food intake and cardiovascular functioning to analgesia, aldosterone secretion, locomotor activity and reproduction. Recently, QRFP has been demonstrated to exert its effects by activating the G protein‑coupled receptor GPR103. QRFP is expressed in the brain and peripherally in the adipose tissue, bladder, colon, testis, parathyroid and thyroid gland, as well as in the prostate gland. Following lung cancer, prostate cancer constitutes the second most frequently diagnosed cancer among men, whilst obesity appears to be a contributing factor for aggressive prostate cancer. In the present study, we sought to investigate the role of QRFP in prostate cancer, using two androgen‑independent human prostate cancer cell lines (PC3 and DU145) as in vitro experimental models and clinical human prostate cancer samples. The expression of both QRFP and GPR103 at the gene and protein level was higher in human prostate cancer tissue samples compared to control and benign prostatic hyperplasia (BHP) samples. Furthermore, in both prostate cancer cell lines used in the present study, QRFP treatment induced the phosphorylation of ERK1/2, p38, JNK and Akt. In addition, QRFP increased cell migration and invasion in these in vitro models, with the increased expression of MMP2. Furthermore, we demonstrated that the pleiotropic adipokine, leptin, increased the expression of QRFP and GPR103 in PC3 prostate cancer cells via a PI3K‑ and MAPK‑dependent mechanism, indicating a novel potential link between adiposity and prostate cancer. Our findings expand the existing evidence and provide novel insight into the implication of QRFP in prostate cancer.

Functional analysis implicating the SNP rs61552325 in ERBB2 as an effector for androgen-insensitive prostate cancer cell invasion

Background

As one of the most common cancers in men, the pathogenesis of prostate cancer has been widely researched. Aberrant activation of the erb-b2 receptor tyrosine kinase 2 (ERBB2) has been found to play a critical role in metastatic prostate cancer. In our previous study, we demonstrated that rs61552325 (Pro1140Ala) located in ERBB2 is strongly correlated to prostate cancer. Therefore, we initially studied the effect of rs61552325 on androgen-independent prostate cancer cell metastasis.

Results

Bioinformatic results demonstrated that the mutant Pro1140Ala likely decrease the stability of the ERBB2 protein and its interactions. The mean migration rate after 6 h for PC3 minor variant cells which carried the G allele was 1.28-fold higher than major variant PC3 cells that carried the C allele (P = 0.016). The mean invasion rate of DU145 putative minor variant cells was 0.40 reducer than negative control cells (P = 5.9E-04).

Methods

rs61552325 major variant (C allele) and minor variant (G allele) were produced by site directed mutagenesis and transfected into DU145 and PC3 cells. A wound healing assay was performed to compare migration abilities between alleles. After knocking down endogenous ERBB2 and then expressing the rs61552325 minor variant, invasion abilities were evaluated with a transwell assay using DU145 and PC3 cells.

Conclusions

Our data showed that the rs61552325 major variant decreases PC3 cell migration and its minor variant depresses DU145 cell invasion, suggesting that rs61552325 is likely an important change during prostate cancer invasion.

Genetic association analysis of the RTK/ERK pathway with aggressive prostate cancer highlights the potential role of CCND2 in disease progression

The RTK/ERK signaling pathway has been implicated in prostate cancer progression. However, the genetic relevance of this pathway to aggressive prostate cancer at the SNP level remains undefined. Here we performed a SNP and gene-based association analysis of the RTK/ERK pathway with aggressive prostate cancer in a cohort comprising 956 aggressive and 347 non-aggressive cases. We identified several loci including rs3217869/CCND2 within the pathway shown to be significantly associated with aggressive prostate cancer. Our functional analysis revealed a statistically significant relationship between rs3217869 risk genotype and decreased CCND2 expression levels in a collection of 119 prostate cancer patient samples. Reduced expression of CCND2 promoted cell proliferation and its overexpression inhibited cell growth of prostate cancer. Strikingly, CCND2 downregulation was consistently observed in the advanced prostate cancer in 18 available clinical data sets with a total amount of 1,095 prostate samples. Furthermore, the lower expression levels of CCND2 markedly correlated with prostate tumor progression to high Gleason score and elevated PSA levels, and served as an independent predictor of biochemical relapse and overall survival in a large cohort of prostate cancer patients. Together, we have identified an association of genetic variants and genes in the RTK/ERK pathway with prostate cancer aggressiveness, and highlighted the potential importance of CCND2 in prostate cancer susceptibility and tumor progression to metastasis.

Association Study of Polymorphisms of Epidermal Growth Factor and Epidermal Growth Factor Receptor With Benign Prostatic Hyperplasia in a Korean Population

Purpose

Recent studies have suggested that specific single-nucleotide polymorphisms (SNPs) contribute to the clinical features of benign prostatic hyperplasia (BPH). In this study, we investigated the relationships of genetic polymorphisms of the epidermal growth factor (EGF) gene and the epidermal growth factor receptor (EGFR) gene with BPH.

Methods

A total of 218 patients with BPH were enrolled in this study. We evaluated the relationship between eight SNPs in the EGF and EGFR genes and prostate volume, prostate-specific antigen (PSA), and International Prostate Symptom Score of BPH patients. Each SNP was genotyped by direct sequencing. Statistical analysis applying codominant, dominant, recessive, and log-additive models was performed via logistic regression.

Results

The rs11568943 and rs11569017 SNPs in the EGF gene showed significant associations with prostate volume (rs11568943: P=0.038 in the log-additive model, P=0.024 in the allele distribution; rs11569017, P=0.031 in the dominant model, P=0.028 in the log-additive model, P=0.020 in the allele distribution). Additionally, the rs3756261, rs11568943, and rs11569017 SNPs of the EGF gene and the rs2293347 SNP of the EGFR gene were associated with PSA levels (P<0.05 in each model, respectively).

Conclusions

These results suggest that the EGF gene may affect prostate volume. In addition, the EGF and EGFR genes may be associated with PSA levels in patients with BPH.

SOCS1 inhibits migration and invasion of prostate cancer cells, attenuates tumor growth and modulates the tumor stroma

BACKGROUND

The suppressor of cytokine signaling 1 (SOCS1) gene is repressed in prostate cancer (PCa) by epigenetic silencing and microRNA miR30d. Increased expression of the SOCS1-targeting miR30d correlates with higher biochemical recurrence, suggesting a tumor suppressor role of SOCS1 in PCa, but the underlying mechanisms are unclear. We have shown that SOCS1 inhibits MET receptor kinase signaling, a key oncogenic pathway in cancer progression. Here we evaluated the role of SOCS1 in attenuating MET signaling in PCa cells and tumor growth in vivo.

METHODS

MET-overexpressing human DU145 and PC3 PCa cell lines were stably transduced with SOCS1, and their growth, migration and invasion of collagen matrix were evaluated in vitro. Cells expressing SOCS1 or the control vector were evaluated for tumor growth in NOD.scid.gamma mice as xenograft or orthotopic tumors.

RESULTS

HGF-induced MET signaling was attenuated in SOCS1-expressing DU145 and PC3 cells. Compared with vector control cells, SOCS1-expressing cells showed reduced proliferation and impaired migration following HGF stimulation. DU145 and PC3 cells showed marked ability to invade the collagen matrix following HGF stimulation and this was attenuated by SOCS1. As xenografts, SOCS1-expressing PCa cells showed significantly reduced tumor growth compared with vector control cells. In the orthotopic tumor model, SOCS1 reduced the growth of primary tumors and metastatic spread. Intriguingly, the SOCS1-expressing DU145 and PC3 tumors showed increased collagen deposition, associated with increased frequency of myofibroblasts.

CONCLUSIONS

Our findings support the tumor suppressor role of SOCS1 in PCa and suggest that attenuation of MET signaling is one of the underlying mechanisms. SOCS1 in PCa cells also appears to prevent the tumor-promoting functions of cancer-associated fibroblasts.

Urologic cancer in China

Cancer remains to be the second most common cause of death, and its incidence and mortality rates are increasing in China. According to the 2015 National Central Cancer Registry (NCCR) of China, the incidence of bladder cancer and prostate cancer ranked sixth and seventh, respectively, in male cancers. The majority of prostate cancer patients were diagnosed at an advanced stage. Early diagnosis of prostate cancer is the key to improve prostate cancer survival in China. Radical prostatectomy or radical radiotherapy is the main treatment for localized prostate cancer, and a comprehensive therapy based on androgen deprivation therapy is the treatment for advanced disease. The most common histologic types of bladder cancer in China were urothelial carcinoma, followed by adenocarcinoma and squamous carcinoma. The majority of patients were diagnosed using white-light cystoscopy with biopsy. Fluorescence and narrow-band imaging cystoscopy had additional detection rates and are becoming more popular. Following Chinese guidelines, most non-muscle invasive bladder cancer patients were treated with diagnostic transurethral resection and more than half of the muscle invasive bladder cancer patients were treated with radical cystectomy. Due to the increased detection rate of kidney tumors by ultrasound in physical examination, the number of incidentally diagnosed renal cell carcinoma has increased. Localized kidney cancers are more and more often treated by nephron-sparing surgery. Radical nephrectomy is still the main treatment option for patients with locally advanced renal cell carcinoma. Both laparoscopic and robotic-assisted laparoscopic surgeries have been used in big medical centers. Both testicular cancer and penile cancer have lower incidence levels than that in Europe. As we have an enormous population base, the absolute patient number is big. The diagnosis and treatment follows the Chinese guidelines. In China, both medical professionals and public should concern more on the early diagnosis, as there is not enough cancer prevention information available. Urologists should also take a more active role in educating the population.

Genetic variants in insulin-like growth factor binding protein-3 are associated with prostate cancer susceptibility in Eastern Chinese Han men

Background

Growing evidence has indicated that insulin-like growth factor binding protein-3 (IGFBP-3) polymorphisms are associated with altered risk of prostate cancer (PCa). However, few studies have been conducted in Chinese population to validate this association.

Materials and methods

Herein, we examined the association between genetic variants in the IGFBP-3 gene and PCa risk in the Chinese Han population based on a genome-wide association study (1,417 cases and 1,008 controls), and replicated three genetic variants loci in an independent case-control study (1,755 cases and 1,523 controls) using Sequenom platform. Logistic regression analyses were performed to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs).

Results

We found that in the discovery stage, rs9691259 (OR =0.691, 95% CI: 0.587–0.814, P<0.001) and rs6950179 (OR =1.420, 95% CI: 1.201–1.677, P<0.001) were significantly associated with PCa risk, whereas rs2854744 showed a marginal association with PCa risk. In the replication stage, the association between rs9691259 and rs6950179 and PCa risk was not replicated, whereas rs2854744 conferred a significant association with PCa risk (OR =1.399, 95% CI: 1.010–1.937, P=0.043). After combining the two stages, we found that rs9691259, rs6950179, and rs2854744 were all significantly associated with PCa risk.

Conclusion

This study suggests that IGFBP-3 genetic variants are significantly associated with PCa risk in the Chinese population.