Definition of a Functional Single Nucleotide Polymorphism in the Cell Migration Inhibitory Gene MIIP That Affects the Risk of Breast Cancer

Plasma One-Carbon Metabolism-Related Micronutrients and the Risk of Breast Cancer: Involvement of DNA Methylation

Findings of epidemiologic studies focusing on the association between one-carbon metabolism-related micronutrients and breast cancer risk, along with the involvement of DNA methylation, have been inconsistent and incomprehensive. We conducted a case-control study in China including 107 paired participants and comprehensively detected 12 plasma one-carbon metabolism-related micronutrients. Genomic DNA methylation was measured using an 850 K chip and differential methylation probes (DMPs) were identified. Multivariate logistic regression was performed to estimate the associations between plasma micronutrients and the odds of breast cancer. The mediation of selected DMPs in micronutrient breast cancer associations was examined using mediation analyses. An inverse association of plasma folate, methionine cycling-related micronutrients (methionine, S-adenosylmethionine, and S-adenosylhomocysteine), and all micronutrients in the choline metabolism and enzymatic factor groups, and a positive association of methionine cycling-related cysteine with breast cancer risk were observed. Nine micronutrients (methionine, cysteine, SAM, folate, choline, betaine, P5P, vitamins B2, and B12) were related to global or probe-specific methylation levels (p < 0.05). The selected DMPs mediated the micronutrient breast cancer associations with an average mediation proportion of 36.43%. This study depicted comprehensive associations between circulating one-carbon metabolism-related micronutrients and breast cancer risk mediated by DNA methylation.

MIIP functions as a novel ligand for ITGB3 to inhibit angiogenesis and tumorigenesis of triple-negative breast cancer

Migration and invasion inhibitory protein (MIIP) has been identified as a tumor suppressor in various cancer types. Although MIIP is reported to exert tumor suppressive functions by repressing proliferation and metastasis of cancer cells, the detailed mechanism is poorly understood. In the present study, we found MIIP is a favorable indicator of prognosis in triple-negative breast cancer. MIIP could inhibit tumor angiogenesis, proliferation, and metastasis of triple-negative breast cancer cells in vivo and in vitro. Mechanistically, MIIP directly interacted with ITGB3 and suppressed its downstream signaling. As a result, β-catenin was reduced due to elevated ubiquitin-mediated degradation, leading to downregulated VEGFA production and epithelial mesenchymal transition. More importantly, we found RGD motif is essential for MIIP binding with ITGB3 and executing efficient tumor-suppressing effect. Our findings unravel a novel mechanism by which MIIP suppresses tumorigenesis in triple-negative breast cancer, and MIIP is thus a promising molecular biomarker or therapeutic target for the disease.

Upregulation of MIIP regulates human breast cancer proliferation, invasion and migration by mediated by IGFBP2

AIMS

The migration and invasion inhibitory protein (MIIP) was initially discovered in a yeast two-hybrid screen for proteins that interact and inhibit the migration and invasion-promoting protein insulin-like growth factor binding protein 2 (IGFBP2). This study aims to evaluate the biological effects of MIIP in breast cancer by targeting IGFBP2.

MATERIALS AND METHODS

Reverse transcription quantitative real-time polymerase chain reaction and Western blotting were used to evaluate the abnormal expression of MIIP and IGFBP2 in breast cancer tissue or breast cancer cell lines. Transfection assay was used to overexpress MIIP protein in breast cancer cells. MTT assay and colony formation assay were used to detect cell viability of breast cancer cells after MIIP overexpression. Transwell and wound-healing assays were used to detect cell invasion and migration after MIIP overexpression.

RESULTS

MIIP was significantly decreased and IGFBP2 was significantly increased in breast cancer tissues versus para cancerous. Breast cancer tissues of HER2 overexpression and Basal-like were more significant than Luminal A and Luminal B. MIIP was obviously downregulated and IGFBP2 was upregulated in MDA-MB-231, SKBR3 and MCF-7 versus MCF-10A especially in MDA-MB-231. Cell proliferation, cell migration and cell invasion were significantly inhibited after overexpression of MIIP. IGFBP2 was downregulated after overexpression of MIIP. The effects of MIIP on cell proliferation, cell migration and invasion were significantly reversed by IGFBP2.

CONCLUSION

The abnormal expression of MIIP in breast cancer affects the cell biological effects. IGFBP2 was regulated via MIIP which may be associated with these biological effects. These results reveal that MIIP can be a potential target for breast cancer treatment.

Comparison of breast cancer risk factors among molecular subtypes: A case-only study

Epidemiological studies have a clear definition of the risk factors for breast cancer. However, it is unknown whether the distribution of these factors differs among breast cancer subtypes. We conducted a hospital‐based case‐only study consisting of 8067 breast cancer patients basing on the Tianjin Cohort of Breast Cancer Cases. Major breast cancer subtypes including luminal A, luminal B, human epidermal growth factor receptor 2 (HER2)‐enriched and basal‐like were defined by estrogen receptor, progesterone receptor, HER2, and Ki‐67 status. Variables including demographic characteristics, reproductive factors, lifestyle habits, imaging examination, and clinicopathologic data were collected for patients. Chi‐square test and one‐way analysis of variance were used to compare the distributions of variables among the four breast cancer subtypes. Multivariate logistic regression was used to estimate the odds ratios and associated 95% confidence intervals where luminal A patients served as the reference group. Overall, more commonality rather than heterogeneity on the distributions of factors was found between the four molecular subtypes of breast cancer. The proportion of overweight and obesity were lower in HER2‐enriched subtype. Women with age at menarche ≤13 years were more likely to be found in basal‐like subtype. Postmenopausal women were more frequent in HER2‐enriched and basal‐like subtypes. Women with benign breast disease and higher breast density were more common in HER2‐enriched subtype. Risk factor scoring showed that total risk scores were similar among the four subtypes. HER2‐enriched and basal‐like subtypes were more frequently diagnosed with large tumors. Calcification was more likely to be found in luminal B and HER2‐enriched subtypes, whereas less distributed in basal‐like subtype. Most of the breast cancer risk factors were similarly distributed among the four major breast cancer subtypes; commonality is predominant.

MIIP gene expression is associated with radiosensitivity in human nasopharyngeal carcinoma cells

The present study aims to investigate the radiosensitization effect of the migration and invasion inhibitory protein (MIIP) gene on nasopharyngeal carcinoma (NPC) cells. The MIIP gene was transfected into NPC 5-8F and CNE2 cells. The level of MIIP was analyzed by quantitative reverse transcription-polymerase chain reaction analysis and western blot. The changes in radiosensitivity of the cells were analyzed by colony formation assay. The changes in cell apoptosis and cycle distribution following irradiation were detected by flow cytometry. The expression of BCL2 associated X, apoptosis regulator/B-cell lymphoma 2 was evaluated using western blot. DNA damage was analyzed by counting γ-H2AX foci. The expression levels of γ-H2AX were evaluated by immunofluorescence and western blot. In a previous study by the authors, the results indicated that the expression of MIIP gene evidently increased in MIIP-transfected 5-8F (5-8F OE) and MIIP-transfected CNE2 (CNE2 OE) cells compared with the parental or negative control cells. In the present study, the survival rate of 5-8F OE and CNE2 OE cells markedly decreased following irradiation (0, 2, 4, 6 and 8 Gy) compared with the negative control (5-8F NC and CNE2 NC) and the untreated (5-8F and CNE2) groups. The expression of MIIP was able to increase apoptosis, which resulted in G2/M cell cycle arrest and DNA damage repair was attenuated in 5-8F and CNE2 cells following irradiation as measured by the accumulation of γ-H2AX. It was indicated that MIIP expression is associated with the radiosensitivity of NPC cells and has a significant role in regulating cell radiosensitivity.

PKCε phosphorylates MIIP and promotes colorectal cancer metastasis through inhibition of RelA deacetylation

EGFR signaling is implicated in NF-κB activation. However, the concrete mechanisms by which the core transducer of NF-κB signaling pathway, RelA/p65 is regulated under EGFR activation remains to be further clarified. Here, we show that EGF stimulation induces PKCε-dependent phosphorylation of migration and invasion inhibitory protein (MIIP) at Ser303; this phosphorylation promotes the interaction between MIIP and RelA in the nucleus, by which MIIP prevents histone deacetylase 6 (HDAC6)-mediated RelA deacetylation, and thus enhances transcriptional activity of RelA and facilitates tumor metastasis. Meanwhile PP1, which functions as a phosphatase, is found to mediate MIIP-S303 dephosphorylation and its expression level inversely correlates with metastatic capability of tumor cells. Moreover, clinical analyses indicate the level of MIIP-S303 phosphorylation correlates with colorectal cancer (CRC) metastasis and prognosis. These findings uncover an unidentified mechanism underlying the precise regulation of NF-κB by EGF, and highlight the critical role of nuclear MIIP in tumor metastasis.In colorectal cancer, EGFR signalling is implicated in metastasis. Here, the authors unravel a mechanism through which EGF stimulation induces MIIP phosphorylation, leading to MIIP interacting with RelA-this prevents RelA deactylation and enhances transcriptional activity, facilitating metastasis.

GAS5 suppresses malignancy of human glioma stem cells via a miR-196a-5p/FOXO1 feedback loop

Glioma stem cells (GSCs) make up highly tumorigenic subpopulations within gliomas, and aberrant expression of GSC genes is a major underlying cause of glioma pathogenesis and treatment failure. The present study characterized the expression and function of long non-coding RNA growth arrest specific 5 (GAS5) in GSCs in order to elucidate the molecular mechanisms by which GAS5 contributes to glioma pathogenesis. We demonstrate that GAS5 suppresses GSC malignancy by binding to miR-196a-5p. miR-196a-5p, an onco-miRNA, stimulates GSC proliferation, migration, and invasion, in addition to reducing levels of apoptosis. miR-196a-5p specifically downregulates the expression of forkhead box protein O1 (FOXO1) by targeting its 3' untranslated region (3'-UTR). FOXO1 upregulates expression of phosphotyrosine interaction domain containing 1 (PID1), thereby inhibiting GSC tumorigenicity and growth. FOXO1 also upregulates migration and invasion inhibitory protein (MIIP), resulting in attenuation of migration and invasion activities. Interestingly, we also show that FOXO1 promotes GAS5 transcription, thus forminga positive feedback loop. These data provide insights into potential new pathways for GSC molecular therapy and suggest that GAS5 may be an efficacious target for glioma treatments.

MIIP accelerates epidermal growth factor receptor protein turnover and attenuates proliferation in non-small cell lung cancer

The migration and invasion inhibitory protein (MIIP) has been discovered recently to have inhibitory functions in cell proliferation and migration. Overexpression of MIIP reduced the intracellular steady-state level of epidermal growth factor receptor (EGFR) protein in lung cancer cells with no effect on EGFR mRNA expression compared to that in the control cells. This MIIP-promoted EGFR protein degradation was reversed by proteasome and lysosome inhibitors, suggesting the involvement of both proteasomal and lysosomal pathways in this degradation. This finding was further validated by pulse-chase experiments using ³⁵S-methionine metabolic labeling. We found that MIIP accelerates EGFR protein turnover via proteasomal degradation in the endoplasmic reticulum and then via the lysosomal pathway after its entry into endocytic trafficking. MIIP-stimulated downregulation of EGFR inhibits downstream activation of Ras and blocks the MEK signal transduction pathway, resulting in inhibition of cell proliferation. The negative correlation between MIIP and EGFR protein expression was validated in lung adenocarcinoma samples. Furthermore, the higher MIIP protein expression predicts a better overall survival of Stage IA-IIIA lung adenocarcinoma patients who underwent radical surgery. These findings reveal a new mechanism by which MIIP inhibits cell proliferation.

A functional genetic variant in fragile-site gene FATS modulates the risk of breast cancer in triparous women

Background

The fragile-site associated tumor suppressor (FATS, formerly known as C10orf90), a regulator of p53-p21 pathway has been involved in the onset of breast cancer. Recent data support the idea that the crosstalk between FATS and p53 may be of physiological importance for reproduction during evolution. The aim of the current study was to test the hypothesis that FATS genetic polymorphism can influence the risk of breast cancer.

Methods

We conducted population-based studies in two independent cohorts comprising 1 532 cases and 1 573 controls in Tianjin of North China, and 804 cases and 835 controls in Guangzhou of South China, coupled with functional validation methods, to investigate the role of FATS genetic variant in breast cancer risk.

Results

We identified a functional variant rs11245007 (905C > T, 262D/N) in fragile-site gene FATS that modulates p53 activation. FATS-262 N exhibited stronger E3 activity to polyubiquitinate p53 than did FATS-262D, leading to the stronger transcriptional activity of p53 and more pronounced stabilization of p53 protein and its activation in response to DNA damage. Case–control studies found that CT or TT genotype was significantly associated with a protective effect on breast cancer risk in women with parity ≥ 3, which was not affected by family history.

Conclusions

Our findings suggest the role of FATS-p53 signaling cascade in suppressing pregnancy-related carcinogenesis and potential application of FATS genotyping in breast cancer prevention.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1570-9) contains supplementary material, which is available to authorized users.

Altered expression and loss of heterozygosity of the migration and invasion inhibitory protein (MIIP) gene in breast cancer

Previous studies have characterized the migration and invasion inhibitory protein (MIIP) as a novel putative tumor-suppressor gene that regulates cell migration and invasion as well as the mitotic checkpoint. The MIIP gene is located on chromosome 1p36.22, a common site for deletion in many solid tumors including breast cancer. In the present study, we evaluated MIIP expression and allelic deletion to gain insight into the role of the MIIP gene in breast cancer. MIIP gene mRNA and protein expression was assessed in 86 matched breast cancer and adjacent normal tissues. Loss of heterogeneity (LOH) of the MIIP gene was determined using single-nucleotide polymorphism (SNP) and microsatellite (MS) markers in 149 breast carcinomas and the corresponding normal lymphocytes. The analysis revealed that the expression levels of MIIP mRNA and protein were downregulated in tumor specimens compared to those in corresponding adjacent tissues. Advanced clinical stage and tumor size >2 cm were associated with a decreased MIIP expression level. Twenty-six percent (37/142) of tumors were shown to have LOH at the MIIP locus by MS and SNP markers. Breast cancer patients with LOH at the SNP marker rs2295283 experienced shorter survival time. The attenuated expression and LOH of the MIIP gene may contribute to the poor prognosis of breast cancer, supporting a tumor-suppressing role of MIIP gene in the pathogenesis of this disease.

Clinical significance of migration and invasion inhibitor protein expression in non-small-cell lung cancer

Migration and invasion inhibitor protein (MIIP) was initially identified in a yeast two-hybrid screen. Recently, MIIP has emerged as a key protein in regulating cell migration and invasion. However, the MIIP expression profile in non-small-cell lung cancer (NSCLC) has not been analyzed. In the present study, MIIP mRNA expression levels were evaluated using the SYBR Green quantitative real-time polymerase chain reaction method in 37 NSCLC specimens and matched normal tissue samples. MIIP protein expression in a further 94 NSCLC specimens was examined with immunohistochemistry. Patient survival data were collected retrospectively, and the association between MIIP protein expression and the five-year overall survival rate was evaluated. The results revealed that MIIP mRNA and protein expression were downregulated in cancer tissues, as compared with the matched normal tissues. MIIP expression levels were significantly associated with pathology and tumor stage, with reduced MIIP mRNA expression levels detected in advanced tumor stage samples. Furthermore, patients with MIIP-positive protein expression had an improved prognosis as compared with those patients with MIIP-negative protein expression, with five-year survival rates of 41.7 and 22.4%, respectively (Kaplan-Meier, log-rank, P=0.028). A significant association between MIIP protein expression and improved prognosis was also demonstrated using univariate and multivariate analyses (P=0.033 and P=0.040, respectively). These results suggest that MIIP may have a potential role in the pathogenesis of NSCLC and also confirm that MIIP is a putative tumor-suppressor gene. Therefore, MIIP may be identified as a functional genetic marker of NSCLC development and prognosis, and may be an attractive therapeutic target for the treatment of lung cancer.

Whole genome sequences of a male and female supercentenarian, ages greater than 114 years

Supercentenarians (age 110+ years old) generally delay or escape age-related diseases and disability well beyond the age of 100 and this exceptional survival is likely to be influenced by a genetic predisposition that includes both common and rare genetic variants. In this report, we describe the complete genomic sequences of male and female supercentenarians, both age >114 years old. We show that: (1) the sequence variant spectrum of these two individuals' DNA sequences is largely comparable to existing non-supercentenarian genomes; (2) the two individuals do not appear to carry most of the well-established human longevity enabling variants already reported in the literature; (3) they have a comparable number of known disease-associated variants relative to most human genomes sequenced to-date; (4) approximately 1% of the variants these individuals possess are novel and may point to new genes involved in exceptional longevity; and (5) both individuals are enriched for coding variants near longevity-associated variants that we discovered through a large genome-wide association study. These analyses suggest that there are both common and rare longevity-associated variants that may counter the effects of disease-predisposing variants and extend lifespan. The continued analysis of the genomes of these and other rare individuals who have survived to extremely old ages should provide insight into the processes that contribute to the maintenance of health during extreme aging.

Arsenic trioxide inhibits invasion/migration in SGC-7901 cells by activating the reactive oxygen species-dependent cyclooxygenase-2/matrix metalloproteinase-2 pathway

Arsenic trioxide (As(2)O(3)) has been shown to inhibit invasion/migration in cancer cells. However, the underlying mechanism is poorly understood. To identify the role of As(2)O(3) in regulating invasion/migration activity in human gastric cancer SGC-7901 cells, the effects of As(2)O(3) on cell invasion/migration activity, the expression of cyclooxygenase-2 (Cox-2), prostaglandin E2 (PGE2), thromboxane B2 (TXB2), leukotriene B4 (LTB4), and matrix metalloproteinase-2 (MMP-2) and intracellular reactive oxygen species (ROS) were examined. Furthermore, N-acetyl-l-cysteine (NAC, a radical scavenger) and celecoxib (a Cox-2 inhibitor) were used to explore the molecular mechanism. The results demonstrated that As(2)O(3) (1 and 2 μmol/L) inhibited invasion/migration activity in SGC-7901 cells at 24 h and suppressed the expression of Cox-2, PGE2 and MMP-2 (P < 0.05), whereas the same treatment had no significant effect on TXB2 and LTB4 expression. In contrast, intracellular ROS were increased (P < 0.05). Moreover, NAC eliminated the excessive ROS and restored the expression of Cox-2 and MMP-2 and invasion/migration activity in As(2)O(3)-treated cells (P < 0.05). These results suggest that ROS may be a critical factor in regulating the invasion/migration process. Moreover, celecoxib significantly decreased Cox-2, MMP-2 and PGE2 expression and inhibited invasion/migration activity in As(2)O(3)-treated cells (P < 0.05), indicating that As(2)O(3) inhibits invasion/migration by regulating the expression of Cox-2/PGE2/MMP-2. In conclusion, these results suggest that increased ROS play a critical role in inhibiting invasion/migration by suppressing the Cox-2/MMP-2 pathway in As(2)O(3)-treated SGC-7901 cells and regulating intracellular ROS levels may be a promising strategy in gastric cancer therapy.

Inhibition of gliomagenesis and attenuation of mitotic transition by MIIP

The migration and invasion inhibitor protein (MIIP, also known as IIp45) was discovered as a negative regulator of cell migration and invasion in glioma. Our previous studies have shown that the MIIP protein was reduced or undetectable in some tissue samples obtained from patients with glioblastoma. The significance of MIIP in gliomagenesis is unknown. In this study, we report that MIIP has an important role in the inhibition of gliomagenesis and attenuation of mitotic transition. Increased MIIP expression levels inhibited colony formation and cell growth of glioma cell lines in vitro, whereas decreased expression by specific small interfering RNA for MIIP resulted in increased cell growth. Expression of MIIP in a glial-specific mouse model blocked glioma development and progression, thus showing that MIIP is an inhibitor of gliomagenesis. Furthermore, we show that MIIP attenuates mitotic transition and results in increased mitotic catastrophe. The biochemical mechanism of MIIP in this process is associated with its regulation of anaphase-promoting complex (APC/C) activity. MIIP interacts directly with Cdc20, and the interaction of MIIP with Cdc20 inhibits APC/C-mediated degradation of cyclin B1. Thus, MIIP attenuates mitotic transition and increases mitotic catastrophe, thereby inhibiting glioma development and progression.