Hypermethylation of the RASSF1A gene promoter as the tumor DNA marker for nasopharyngeal carcinoma

Background RASSF1A is a tumor suppressor gene. The methylation of RASSF1A has been reported to be associated with nasopharyngeal tumorigenesis. However, the heterogeneity was high among different studies. A meta-analysis was performed to evaluate the value of RASSF1A methylation for the diagnosis and early screening of nasopharyngeal carcinoma. Methods Relevant articles were identified by searching the MEDLINE database. Frequency and odds ratio (OR) were applied to estimate the effect of CDH-1 methylation based on random-/fixed-effect models. The meta-analysis was performed by using MedCalc® software. Subgroup analyses were performed by test method, ethnicity, and source of nasopharyngeal carcinoma samples to determine likely sources of heterogeneity. Results A total of 17 studies, including 1688 samples (1165 nasopharyngeal carcinoma samples, and 523 from non-cancerous samples) were used for the meta-analysis. The overall frequencies of RASSF1A methylation were 59.68% and 2.65% in case-group and control-group, respectively. By removing the poor relative studies, the heterogeneity was not observed among the studies included. The association between RASSF1A gene methylation and the risk of nasopharyngeal carcinoma was also confirmed by calculating the OR value of 30.32 (95%CI = 18.22–50.47) in the fixed-effect model (Q = 16.41, p = 0.36,I 2 = 8.62, 95% CI = 0.00–45.27). Additionally, the significant association was also found between the methylation of the RASSF1A gene and the subgroups. Conclusions This is the first meta-analysis that has provided scientific evidence that the methylation of RASSF1A is the potential diagnosis, prognosis, and early screening biomarker for nasopharyngeal carcinoma.

Increased Sensitivity of Detection of RASSF1A and GSTP1 DNA Fragments in Serum of Prostate Cancer Patients: Optimisation of Diagnostics Using OBBPA-ddPCR

Identification of aberrant DNA methylation is a promising tool in prostate cancer (PCa) diagnosis and treatment. In this study, we evaluated a two-step method named optimised bias-based preamplification followed by digital PCR (OBBPA-dPCR). The method was used to identify promoter hypermethylation of 2 tumour suppressor genes RASSF1A and GSTP1 in the circulating cell-free DNA (cfDNA) from serum samples of PCa patients (n = 75), benign prostatic hyperplasia (BPH, n = 58), and healthy individuals (controls, n = 155). The PCa cohort was further subdivided into subgroups comprising (I) patients with Gleason Scores (GS) ≤ 7 (n = 55), (II) GS ≥ 8 (n = 10), and (III) patients with metastatic PCa diagnosis (n = 10). We found that RASSF1A methylation levels were significantly increased in all 3 PCa subgroups compared to the controls and BPH cohorts (p < 0.01 for all comparisons). Fractional abundances of methylated GSTP1 DNA fragments were significantly increased in subgroup III of metastatic PCa patients (p < 0.001). RASSF1A methylation analysis was found to be beneficial as a complementary biomarker where further diagnostic validation is most crucial. In combination with free PSA, RASSF1A methylation status helps to identify PCa patients with GS ≥ 8 and grey-zone total PSA values between 2–10 ng/mL. In our study, PCR biases between 80–90% were sufficient to detect minute amounts of tumour DNA with high signal-to-noise ratios as well as high analytical sensitivity and specificity. Both RASSF1A and GSTP1 exhibited strongly increased DNA methylation levels in all metastatic PCa patients. Our data indicates a superior sensitivity of epigenetic biomarker analyses in early detection of PCa metastases that should also help to improve PCa therapy.

Performance Evaluation of SHOX2 and RASSF1A Methylation for the Aid in Diagnosis of Lung Cancer Based on the Analysis of FFPE Specimen

Emerging molecular diagnostic methods are more sensitive and objective, which can overcome the intrinsic failings of morphological diagnosis. Here, a RT-PCR-based in vitro diagnostic test kit (LungMe®) was developed and characterized to simultaneously quantify the DNA methylation of SHOX2 and RASSF1A in FFPE tissue specimens. The clinical manifestations were evaluated in 251 FFPE samples with specificity and sensitivity of 90.4 and 89.8%, respectively. Furthermore, the quantitative analysis shows that the degree of SHOX2 methylation was correlated with the stages of lung cancer, but not in the case of RASSF1A. Our observation indicated that the DNA methylation of SHOX2 and RASSF1A may play different roles in cancer development. Comparison of the methylation levels of SHOX2 and RASSF1A between cancer and cancer-adjacent specimens (n = 30), showed they have “epigenetic field defect”. As additional clinical validation, the hypermethylation of SHOX2 and RASSF1A was detected not only in surgical operative specimens, but also in histopathological negative puncture biopsies. SHOX2 and RASSF1A methylation detection can be used to increase sensitivity and NPV, which provide us with a more accurate method of differential diagnosis and are likely to be rapidly applied in clinical examinations.

RASSF1A regulates the abnormal cell proliferation in psoriasis via inhibition of YAP

Background: Psoriasis is a chronic, inflammatory skin disease with high incidence, treatment resistance, and high recurrence. Currently, the exact etiology and pathogenesis of psoriasis are unclear. The goal of this study was to characterize the effect of the upstream negative regulator RAS-association domain family 1A (RASSF1A) on Yes-associated protein (YAP) in psoriasis. Methods: Skin lesions of 22 patients with psoriasis and 19 controls with normal skin tissue were used. Human epidermal keratinocytes were stimulated with M5 (IL-1 α, IL-17, IL-22, TNF-α, oncostatin M) to establish the psoriatic cell model. Methylation inhibitor 5-Aza-CdR was prepared at different concentrations (5, 10, 20 μmol/L). Cells were infected with lentivirus vector overexpressing RASSF1A. Twenty-five 6–8-week-old female BALB/c mice were used to establish the psoriatic mouse model. Mice were randomly divided into five groups: control (Vaseline applied daily), psoriasis (imiquimod applied daily), and the three different 5-Aza-CdR concentrations (applied daily with imiquimod). Methylation-specific PCR (MSP) was used to detect RASSF1A methylation and immunohistochemistry was used to detect RASSF1A expression in skin lesions. After adding 5-Aza-CdR or lentivirus vector overexpressing RASSF1A, YAP expression, cell proliferation, cell cycle, apoptosis, inflammatory cytokines, and related signal pathway activity were investigated. Results: As RASSF1A methylation level increased, its expression in patients with psoriasis and mice with skin lesions decreased. Addition of 5-Aza-CdR or lentivirus vector overexpressing RASSF1A increased the expression of RASSF1A, reduced the expression of YAP and inflammatory cytokines, cell proliferation, as well as AKT, ERK, STAT3, and NF-κB signaling pathway activities, induced cell cycle arrest in G0/G1 phase, increased apoptosis, and improved skin lesions. Conclusions: RASSF1A inhibited the proliferation of psoriatic cells, induced apoptosis, and reduced the expression of inflammatory factors by inhibiting YAP expression. Based on our findings, targeted drugs that can inhibit RASSF1A methylation and increase its expression may be useful in the treatment of psoriasis.

RASSF1A Regulates the Abnormal Cell Proliferation in Psoriasis via Inhibition of YAP

Background: Psoriasis is a chronic, inflammatory skin disease with high incidence, treatment resistance, and high recurrence. Currently, the exact etiology and pathogenesis are unclear. The goal of this study was to characterize the role of the upstream negative regulator RAS-association domain family 1A (RASSF1A) on Yes-associated protein (YAP) in psoriasis.Methods: Skin lesions of 22 psoriasis patients and 19 normal skin tissue controls were used. Human epidermal keratinocytes were stimulated with M5 (IL-1 α, IL-17, IL-22, TNF-α, oncostatin M), to establish the psoriatic cell model. Methylation inhibitor, 5-Aza-CdR was prepared at different concentrations (5, 10, 20 μmol/L). Cells were infected with lentivirus vector overexpressing RASSF1A. Twenty-five 6-8-week-old female BALB/c mice were used to establish the psoriatic mouse model. Mice were randomly divided into five groups: control (Vaseline applied daily), psoriasis (imiquimod applied daily), and the three different 5-Aza-CdR concentrations (applied daily with imiquimod). Methylation specific PCR (MSP) was used to detect RASSF1A methylation, and immunohistochemistry was used to detect RASSF1A expression in skin lesions. After adding 5-Aza-CdR or lentivirus vector overexpressing RASSF1A, YAP expression, cell proliferation, cell cycle, apoptosis, inflammatory cytokines and related signal pathway activity were detected.Results: As RASSF1A methylation level increased, its expression in psoriasis patients and mice with skin lesions decreased. Addition of 5-Aza-CdR or lentivirus vector overexpressing RASSF1A increased the expression of RASSF1A, reduced the expression of YAP and inflammatory cytokines, cell proliferation, as well as AKT, ERK, STAT3 and NF-κB signaling pathway activities, induced cell cycle arrest in G0/G1 phase, increased apoptosis, and improved skin lesions.Conclusions: RASSF1A inhibited the proliferation of psoriatic cells, induced apoptosis, and reduced the expression of inflammatory factors by inhibiting YAP expression. Based on our findings, targeted drugs that can inhibit RASSF1A methylation and increase its expression may be useful in the treatment of psoriasis.

Association between methylation of RASSF1A and breast cancer: a meta-analysis

Objective: To systematically evaluate the relationship between methylation of RASSF1A and breast cancer. Methods: Screening the literatures that retrieved from PubMed, Cochrane Library and Ovid. Evaluate the quality of included studies. Data analysis performed by Revman5.3 and Stata12.0 software. Results: A total of 7 articles were included in this meta-analysis, including 1485 samples. The results indicate that the positive rate of RASSF1A methylation have conspicuous difference between breast cancer and normal group, breast cancer VS benign breast lesion, as well. Respectively (BC VS N, OR=4.52, 95%CI (2.02~10.10), P=0.0002; BC VS BBL, OR=3.63, 95%CI (2.50~5.43), P=0.0002; BBL VS N, OR=0.83, 95%CI (0.53~1.30), P=0.42). Conclusion: This meta-analysis confirms that hyper-methylation of RASSF1A is closely related to breast tumor. And it is of significance in differentiating benign breast lesions from malignant breast lesions.

Methylation Dynamics of RASSF1A and Its Impact on Cancer

5-methyl cytosine (5mC) is a key epigenetic mark entwined with gene expression and the specification of cellular phenotypes. Its distribution around gene promoters sets a barrier for transcriptional enhancers or inhibitor proteins binding to their target sequences. As a result, an additional level of regulation is added to the signals that organize the access to the chromatin and its structural components. The tumor suppressor gene RASSF1A is a microtubule-associated and multitasking scaffold protein communicating with the RAS pathway, estrogen receptor signaling, and Hippo pathway. RASSF1A action stimulates mitotic arrest, DNA repair and apoptosis, and controls the cell cycle and cell migration. De novo methylation of the RASSF1A promoter has received much attention due to its increased frequency in most cancer types. RASSF1A methylation is preceded by histones modifications and could represent an early molecular event in cell transformation. Accordingly, RASSF1A methylation is proposed as an epigenetic candidate marker in many cancer types, even though an inverse correlation of methylation and expression remains to be fully ascertained. Some findings indicate that the epigenetic abrogation of RASSF1A can promote the alternative expression of the putative oncogenic isoform RASSF1C. Understanding the complexity and significance of RASSF1A methylation is instrumental for a more accurate determination of its biological and clinical role. The review covers the molecular events implicated in RASSF1A methylation and gene silencing and provides a deeper view into the significance of the RASSF1A methylation patterns in a number of gastrointestinal cancer types.

Diagnostic value of RASSF1A methylation for breast cancer: a meta-analysis

Background: Numerous studies reported that RAS-association domain family 1 isoform A (RASSF1A) methylation might act as diagnostic biomarker for breast cancer (BC), this meta-analysis aimed to evaluate the value of RASSF1A methylation for diagnosing BC. Methods: Such databases as PubMed, Cochrane Library and Web of Science databases were searched for literatures until May 2019. A meta-analysis was performed utilizing STATA and Revman softwares. Furthermore, subgroup analysis was adopted to determine likely sources of heterogeneity. Results: Totally 19 literatures with 1849 patients and 1542 controls were included in the present study. Sensitivity, specificity, diagnostic odds ratio (DOR) and the area under the summary receiver operating characteristic curve (AUC) of RASSF1A methylation for diagnosing BC were 0.49, 0.95, 19.0 and 0.83, respectively. The sensitivity (0.54 vs 0.43), DOR (30.0 vs 10.0) and AUC (0.84 vs 0.81) of RASSF1A methylation in Caucasian were higher than other ethnicities. The sensitivity (0.64 vs 0.57), DOR (21.0 vs 14.0) and AUC (0.89 vs 0.86) of methylation-specific PCR (MSP) were superior to other methods (q-MSP, OS-MSP and MethyLight). The sensitivity, DOR and AUC of serum RASSF1A methylation vs RASSF1A methylation in other samples (tissue or plasma) were 0.55 vs 0.40, 22.0 vs 14.0 and 0.86 vs 0.74, respectively. Conclusions: RASSF1A methylation might be a potential diagnostic biomarker for BC. Considering its low sensitivity and high specificity, it should combine with others to upgrade the sensitivity. Besides, under such conditions, MSP detection, serum RASSF1A methylation and Caucasian are shown to be more effective and suitable for diagnosing BC.