The MKK7 p.Glu116Lys Rare Variant Serves as a Predictor for Lung Cancer Risk and Prognosis in Chinese

A novel LINC00478 serves as a tumor suppressor in endometrial carcinoma progression

BACKGROUND

Long noncoding RNAs (lncRNAs) are involved in the pathogenesis and progression of various cancers, but their roles in endometrial cancer (EC) are largely unknown.

METHODS

The expressions of LINC00478 and PTBP1 in EC tissues were determined by RT-qPCR. Cell counting kit-8, flow cytometry and Transwell assays were executed for detecting the roles of LINC00478 in EC cells proliferation, migration and invasion. The mouse-xenograft models were established by subcutaneous injection in vivo. The interaction between LINC00478 and PTBP1 was confirmed by RNA pull-down assay and RNA-binding protein immunoprecipitation assay.

RESULTS

LINC00478 was significantly down-regulated in EC tissues while compared to that in their paracancerous samples, and a higher expression level of LINC00478 was negatively correlated with clinical progress of EC patients. Functional experiments in vivo and in vitro revealed that LINC00478 overexpression could dramatically retard the proliferation of EC cells, decrease the rate of colony formation, suppress the migration and invasion abilities of EC cells in vitro and inhibit tumor growth in vivo. Mechanistically, LINC00478 regulated the expression of PTBP1, a key factor in the Warburg effect, and affected the metabolic process of EC cells.

CONCLUSIONS

LINC00478 acts as a tumor suppressor in EC by negatively controlling PTBP1 expression and influencing the Warburg effect, providing a potential biomarker and therapeutic target for patients with EC.

Potential Impact of Cancer Susceptibility Genes on Lung Cancer Metastasis

Background. Studies of prognosis-related molecular markers are an important tool to uncover the mechanism of tumour metastasis. Cancer susceptibility gene testing is an important tool for genetic counselling of cancer risk. However, the impact of lung cancer susceptibility genes (LCSGs) on lung cancer metastasis and prognosis has not been well studied. Methods. The list of lung cancer susceptibility genes was retrospectively analysed and updated. After expression profiling and functional analysis, LCSG-based signatures for prognosis were identified by Cox regression and LASSO regression analyses. For translational purposes, nomograms integrating LCSGs and clinical characteristics were constructed. Results. A total of 301 LCSGs were employed for modelling. For lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC), 10-gene and 7-gene signatures were created and independently validated. The LCSG-based risk score could stratify LUAD survival (univariate: hazard ratio $\left(\text{HR}\right)=1.076$ , 95% confidence interval $\left(\text{CI}\right)=1.049$ –1.103, $P<0.001$ ; multivariate: $\text{HR}=1.066$ , 95% $\text{CI}=1.037$ –1.095, $P<0.001$ ) and LUSC survival (univariate: $\text{HR}=1.149$ , 95% $\text{CI}=1.066$ −1.239, $P<0.001$ ; multivariate: $\text{HR}=1.129$ , 95% $\text{CI}=1.038$ −1.228, $P=0.005$ ). One of the processes affected by differentially expressed genes in both LUAD and LUSC was the negative regulation of epithelial cell differentiation. Conclusions. Overall, novel LCSG-based gene signatures for LUAD and LUSC were constructed. These findings could expand the understanding of the impact of LCSG expression on cancer metastasis and prognosis.

Mitogen-activated protein kinase kinase 7 in inflammatory, cancer, and neurological diseases

Stress-activated mitogen-activated protein kinase kinase 7 (MKK7) is a member of the dual-specificity mitogen-activated protein kinase family. In the human body, MKK7 controls essential physiological processes, including but not limited to proliferation and differentiation in multiple tissues and organs. MKK7, along with the MKK4 pathway, has been implicated in stress-activated activities and biological events that are mediated by c-Jun N-terminal kinase (JNK) signaling. Although numerous studies have been performed to identify the role of JNK in multiple biological processes, there are limited publications that focus on dissecting the independent role of MKK7. Recent research findings have spurred testing via in vivo genetically deficient models, uncovering previously undocumented JNK-independent functions of MKK7. Here we discuss both JNK-dependent and-independent functions of MKK7 in vivo. This review summarizes the role of MKK7 in inflammation, cytokine production, cancer, and neurological diseases.

Inhibition of the MAP2K7-JNK pathway with 5Z-7-oxozeaenol induces apoptosis in T-cell acute lymphoblastic leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive pediatric leukemia with a worse prognosis than most frequent B-cell ALL due to a high incidence of treatment failures and relapse. Our previous work showed that loss of the pioneer factor KLF4 in a NOTCH1-induced T-ALL mouse model accelerated the development of leukemia through expansion of leukemia-initiating cells and activation of the MAP2K7 pathway. Similarly, epigenetic silencing of the KLF4 gene in children with T-ALL was associated with MAP2K7 activation. Here, we showed the small molecule 5Z-7-oxozeaenol (5Z7O) induces dose-dependent cytotoxicity in a panel of T-ALL cell lines mainly through inhibition of the MAP2K7-JNK pathway, which further validates MAP2K7 as a therapeutic target. Mechanistically, 5Z7O-mediated apoptosis was caused by the downregulation of regulators of the G2/M checkpoint and the inhibition of survival pathways. The anti-leukemic capacity of 5Z7O was evaluated using leukemic cells from two mouse models of T-ALL and patient-derived xenograft cells generated using lymphoblasts from pediatric T-ALL patients. Finally, a combination of 5Z7O with dexamethasone, a drug used in frontline therapy, showed synergistic induction of cytotoxicity. In sum, we report here that MAP2K7 inhibition thwarts survival mechanisms in T-ALL cells and warrants future pre-clinical studies for high-risk and relapsed patients.

Nongenomic Actions of Thyroid Hormone: The Integrin Component

The extracellular domain of plasma membrane integrin αvβ3 contains a cell surface receptor for thyroid hormone analogues. The receptor is largely expressed and activated in tumor cells and rapidly dividing endothelial cells. The principal ligand for this receptor is l-thyroxine (T₄), usually regarded only as a prohormone for 3,5,3'-triiodo-l-thyronine (T₃), the hormone analogue that expresses thyroid hormone in the cell nucleus via nuclear receptors that are unrelated structurally to integrin αvβ3. At the integrin receptor for thyroid hormone, T₄ regulates cancer and endothelial cell division, tumor cell defense pathways (such as anti-apoptosis), and angiogenesis and supports metastasis, radioresistance, and chemoresistance. The molecular mechanisms involve signal transduction via mitogen-activated protein kinase and phosphatidylinositol 3-kinase, differential expression of multiple genes related to the listed cell processes, and regulation of activities of other cell surface proteins, such as vascular growth factor receptors. Tetraiodothyroacetic acid (tetrac) is derived from T₄ and competes with binding of T₄ to the integrin. In the absence of T₄, tetrac and chemically modified tetrac also have anticancer effects that culminate in altered gene transcription. Tumor xenografts are arrested by unmodified and chemically modified tetrac. The receptor requires further characterization in terms of contributions to nonmalignant cells, such as platelets and phagocytes. The integrin αvβ3 receptor for thyroid hormone offers a large panel of cellular actions that are relevant to cancer biology and that may be regulated by tetrac derivatives.

MKK7, the essential regulator of JNK signaling involved in cancer cell survival: a newly emerging anticancer therapeutic target

One of the mitogen-activated protein kinases (MAPKs), c-Jun NH2-terminal protein kinase (JNK) plays an important role in regulating cell fate, such as proliferation, differentiation, development, transformation, and apoptosis. Its activity is induced through the interaction of MAPK kinase kinases (MAP3Ks), MAPK kinases (MAP2Ks), and various scaffolding proteins. Because of the importance of the JNK cascade to intracellular bioactivity, many studies have been conducted to reveal its precise intracellular functions and mechanisms, but its regulatory mechanisms remain elusive. In this review, we discuss the molecular characterization, activation process, and physiological functions of mitogen-activated protein kinase kinase 7 (MKK7), the MAP2K that most specifically controls the activity of JNK. Understanding the role of MKK7/JNK signaling in physiological conditions could spark new hypotheses for targeted anticancer therapies.

Polymorphisms of rs4787050 and rs8045980 are associated with lung cancer risk in northeast Chinese female nonsmokers

Aim: We studied the association between two single-nucleotide polymorphisms (SNPs: rs4787050 and rs8045980) in RBFOX1 and lung cancer risk, and explored the interaction between the two SNPs and exposure to cooking oil fume on lung cancer risk in northeast Chinese female nonsmokers. Methods: Northeast Chinese female nonsmokers were enrolled into the study (people with lung cancer, 647; people without lung cancer, 675). All statistical analyses were performed using SPSS software. Results: The SNPs rs4787050 and rs8045980 showed a significant association with susceptibility to lung cancer. Moreover, cooking oil fume exposure was found to increase the risk of lung cancer. However, no gene-environment interactions were discovered. Conclusion: The present study revealed that rs4787050 and rs8045980 in RBFOX1 may be meaningful as a novel biomarker for lung cancer susceptibility.

Contributions of Thyroid Hormone to Cancer Metastasis

Acting at a cell surface receptor on the extracellular domain of integrin αvβ3, thyroid hormone analogues regulate downstream the expression of a large panel of genes relevant to cancer cell proliferation, to cancer cell survival pathways, and to tumor-linked angiogenesis. Because αvβ3 is involved in the cancer cell metastatic process, we examine here the possibility that thyroid hormone as l-thyroxine (T4) and the thyroid hormone antagonist, tetraiodothyroacetic acid (tetrac), may respectively promote and inhibit metastasis. Actions of T4 and tetrac that are relevant to cancer metastasis include the multitude of synergistic effects on molecular levels such as expression of matrix metalloproteinase genes, angiogenesis support genes, receptor tyrosine kinase (EGFR/ERBB2) genes, specific microRNAs, the epithelial–mesenchymal transition (EMT) process; and on the cellular level are exemplified by effects on macrophages. We conclude that the thyroid hormone-αvβ3 interaction is mechanistically linked to cancer metastasis and that modified tetrac molecules have antimetastatic activity with feasible therapeutic potential.

Functional Polymorphism in the MSI1 Gene Promoter Confers a Decreased Risk of Lung Cancer in Chinese by Reducing MSI1 Expression

Background:

Musashi1 (MSI1) is a characteristic stem cell marker that regulates the balance between cell self-renewal and differentiation. Evidence has identified MSI1 as a pivotal oncogenic regulator in diverse malignancies. However, little evidence uncovers the role of genetic variations of MSI1 gene in cancer etiology.

Objective:

The aim of this study was to investigate the association between genetic variants in the MSI1 gene and lung cancer risk.

Methods:

Based on a two-stage retrospective study with a total of 1559 patients with lung cancer and 1667 healthy controls, we evaluated the relevance between three putative functional SNPs in the MSI1 promoter (i.e., -2696T>C[rs7959801], -2297T>C[rs3742038] and -1081C>T[rs34570155]) and lung cancer risk.

Results:

We found that the SNP rs7959801T>C was significantly associated with lung cancer susceptibility. Compared to those with rs7959801TT wild-genotype, individuals with CT/CC variant genotypes exerted consistently beneficial roles in lung cancer risk in the discovery set (adjusted odd ratios [OR] = 0.67; 95% confidence interval [CI] = 0.57-0.80), and in the validation set (OR=0.69; 95%CI=0.54-0.88). Functional assays indicated that the allele transformation from T to C in rs7959801 of MSI1 gene arrestingly decreased its transcription activity in vitro. Furthermore, the expression levels of MSI1 were significantly lower in the patients with CT/CC variants than in those who were with TT genotype.

Conclusion:

Our findings suggested that the rs7959801T>C polymorphism in the MSI1 promoter conferred a decreased risk to lung cancer by reducing the expression of MSI1 and it may be a promising indicator for lung cancer predisposition.

miR-125b expression affects tumor growth of multiple myeloma via targeting MKK7

Many miRNAs are reported to be involved in tumor development. The underlying mechanism of miRNAs driving multiple myeloma (MM) progress remains elusive. This study is to investigate the effect of miR-125b, a brain-enriched microRNA, on mitogen-activated protein kinase 7 (MKK7) in vivo. We found significantly up-regulation of miR-125b and deregulation of MKK7 in MM. The inverse correlation was further confirmed in multiple myeloma samples and cell lines. In addition, MKK7 was identified as a downstream target gene of miR-125b, which could bind to the 3' UTR of MKK7. Overexpression of miR-125b was associated with decreased MKK7 expression and miR-125b antagonisminhibited cell proliferation and clonogenicity. Taken together, our results demonstrated that MKK7 could function as an important tumor suppressor neutralized by miR-125b in MM, suggesting that miR-125b may be a novel potential molecular therapeutic target in the treatment of MM.

Polymorphisms of protamine genes contribute to male infertility susceptibility in the Chinese Han population

Protamine (PRM) plays important roles in the packaging of DNA within the sperm nucleus. To investigate the role of PRM1/2 and transition protein 1 (TNP1) polymorphisms in male infertility, 636 infertile men and 442 healthy individuals were recruited into this case-controlled study of the Chinese Han population, using MassARRAY technology to analyze genotypes. Our analysis showed that there were no significant differences between controls and infertile cases among the five single nucleotide polymorphisms identified in PRM1, PRM2 and TNP1 [rs737008 (G/A), rs2301365 (C/A), rs2070923 (C/A), rs1646022 (C/G) and rs62180545 (A/G)]. However, we found that the PRM1 and PRM2 haplotypes GCTGC, TCGCA and TCGCC exhibited significant protective effects against male infertility compared to fertile men, while TCGGA, GCTCC and TCGGC represented significant risk factors for spermatogenesis. Our data showed that rs737008 and rs2301365 in PRM1, and rs1646022 in PRM2, were significantly associated with male infertility and that gene–gene interaction played a role in male infertility. A linkage disequilibrium plot for the five SNPs showed that rs737008 was strongly linked with both rs2301365 and rs2070923. These findings are likely to help improve our understanding of the etiology of male infertility. Further studies should include a larger number of genes and SNPs, particularly growing critical genes; such studies will help us to unravel the effect of individual genetic factors upon male infertility.