HPV E7-drived ALKBH5 promotes cervical cancer progression by modulating m6A modification of PAK5.

Human papillomavirus (HPV) infection is a causative agent of cervical cancer (CC). N6-methyladenosine (m6A) modification is implicated in carcinogenesis and tumor progression. However, the involvement of m6A modification in HPV-involved CC remains unclear. Here we showed that HPV E6/7 oncoproteins affected the global m6A modification and E7 specifically promoted the expression of ALKBH5. We found that ALKBH5 was significantly upregulated in CC and might serve as a valuable prognostic marker. Forced expression of ALKBH5 enhanced the malignant phenotypes of CC cells. Mechanistically, we discovered that E7 increased ALKBH5 expression through E2F1-mediated activation of the H3K27Ac and H3K4Me3 histone modifications, as well as post-translational modification mediated by DDX3. ALKBH5-mediated m6A demethylation enhanced the expression of PAK5. The m6A reader YTHDF2 bound to PAK5 mRNA and regulated its stability in an m6A-dependent manner. Moreover, ALKBH5 promoted tumorigenesis and metastasis of CC by regulating PAK5. Overall, our findings herein demonstrate a significant role of ALKBH5 in CC progression in HPV-positive cells. Thus, we propose that ALKBH5 may serve as a prognostic biomarker and therapeutic target for CC patients.

COPS6 promotes tumor progression and reduces CD8+ T cell infiltration by repressing IL-6 production to facilitate tumor immune evasion in breast cancer.

Due to poor T cell infiltration, tumors evade immune surveillance. Increased CD8+ T cell infiltration in breast cancer suggests a satisfactory response to immunotherapy. COPS6 has been identified as an oncogene, but its role in regulating antitumor immune responses has not been defined. In this study, we investigated the impact of COPS6 on tumor immune evasion in vivo. Tumor transplantation models were established in C57BL/6 J mice and BALB/c nude mice. Flow cytometry was conducted to identify the role of COPS6 on tumor-infiltrating CD8+ T cells. By analyzing the TCGA and GTEx cohort, we found that COPS6 expression was significantly up-regulated in a variety of cancers. In human osteosarcoma cell line U2OS and non-small cell lung cancer cell line H1299, we showed that p53 negatively regulated COPS6 promoter activity. In human breast cancer MCF-7 cells, COPS6 overexpression stimulated p-AKT expression as well as the proliferation and malignant transformation of tumor cells, whereas knockdown of COPS6 caused opposite effects. Knockdown of COPS6 also significantly suppressed the growth of mouse mammary cancer EMT6 xenografts in BALB/c nude mice. Bioinformatics analysis suggested that COPS6 was a mediator of IL-6 production in the tumor microenvironment and a negative regulator of CD8+ T cell tumor infiltration in breast cancer. In C57BL6 mice bearing EMT6 xenografts, COPS6 knockdown in the EMT6 cells increased the number of tumor-infiltrating CD8+ T cells, while knockdown of IL-6 in COPS6KD EMT6 cells diminished tumor infiltrating CD8+ T cells. We conclude that COPS6 promotes breast cancer progression by reducing CD8+ T cell infiltration and function via the regulation of IL-6 secretion. This study clarifies the role of p53/COPS6/IL-6/CD8+ tumor infiltrating lymphocytes signaling in breast cancer progression and immune evasion, opening a new path for development of COPS6-targeting therapies to enhance tumor immunogenicity and treat immunologically "cold" breast cancer.

METTL3 potentiates progression of cervical cancer by suppressing ER stress via regulating m6A modification of TXNDC5 mRNA.

N6-methyladenosine (m6A) is the most abundant chemical modification on mRNA and plays significant roles in many bioprocesses. However, the functions of m6A on cervical cancer (CC) tumorigenesis remain unclear. Here we found methyltransferase-like 3 (METTL3), a core member of the m6A methyltransferase family, was greatly upregulated as an independent prognostic factor in CC. Mechanistically, the transcription factor ETS1 recruited P300 and WDR5 which separately mediated H3K27ac and H3K4me3 histone modification in the promoter of METTL3 and induced METTL3 transcription activation. Furthermore, we identified TXNDC5 as a target of METTL3-mediated m6A modification through MeRIP-seq, and revealed that METTL3-mediated TXNDC5 expression relied on the m6A reader-dependent manner. Functionally, we verified that METTL3 promoted proliferation and metastasis of CC cells by regulating of TXNDC5 expression through in vitro and in vivo experiments. In addition, our study verified the effect of METTL3/TXNDC5 axis on ER stress. Taken together, METTL3 facilitates the malignant progression of CC, suggesting that METTL3 might be a potential prognostic biomarker and therapeutic target for CC.

MicroRNA-138-1-3p sensitizes sorafenib to hepatocellular carcinoma by targeting PAK5 mediated ß-catenin/ABCB1 signaling pathway.

BACKGROUND: Sorafenib is a kinase inhibitor that is used as a first-line therapy in advanced hepatocellular carcinoma (HCC) patients. However, the existence of sorafenib resistance has limited its therapeutic effect. Through RNA sequencing, we demonstrated that miR-138-1-3p was downregulated in sorafenib resistant HCC cell lines. This study aimed to investigate the role of miR-138-1-3p in sorafenib resistance of HCC. METHODS: In this study, quantitative real-time PCR (qPCR) and Western Blot were utilized to detect the levels of PAK5 in sorafenib-resistant HCC cells and parental cells. The biological functions of miR-138-1-3p and PAK5 in sorafenib-resistant cells and their parental cells were explored by cell viability assays and flow cytometric analyses. The mechanisms for the involvement of PAK5 were examined via co-immunoprecipitation (co-IP), immunofluorescence, dual luciferase reporter assay and chromatin immunoprecipitation (ChIP). The effects of miR-138-1-3p and PAK5 on HCC sorafenib resistant characteristics were investigated by a xenotransplantation model. RESULTS: We detected significant down-regulation of miR-138-1-3p and up-regulation of PAK5 in sorafenib-resistance HCC cell lines. Mechanistic studies revealed that miR-138-1-3p reduced the protein expression of PAK5 by directly targeting the 3'-UTR of PAK5 mRNA. In addition, we verified that PAK5 enhanced the phosphorylation and nuclear translocation of ß-catenin that increased the transcriptional activity of a multidrug resistance protein ABCB1. CONCLUSIONS: PAK5 contributed to the sorafenib resistant characteristics of HCC via ß-catenin/ABCB1 signaling pathway. Our findings identified the correlation between miR-138-1-3p and PAK5 and the molecular mechanisms of PAK5-mediated sorafenib resistance in HCC, which provided a potential therapeutic target in advanced HCC patients.

Mesenchymal stem cell treatment for peripheral nerve injury: a narrative review.

Peripheral nerve injuries occur as the result of sudden trauma and lead to reduced quality of life. The peripheral nervous system has an inherent capability to regenerate axons. However, peripheral nerve regeneration following injury is generally slow and incomplete that results in poor functional outcomes such as muscle atrophy. Although conventional surgical procedures for peripheral nerve injuries present many benefits, there are still several limitations including scarring, difficult accessibility to donor nerve, neuroma formation and a need to sacrifice the autologous nerve. For many years, other therapeutic approaches for peripheral nerve injuries have been explored, the most notable being the replacement of Schwann cells, the glial cells responsible for clearing out debris from the site of injury. Introducing cultured Schwann cells to the injured sites showed great benefits in promoting axonal regeneration and functional recovery. However, there are limited sources of Schwann cells for extraction and difficulties in culturing Schwann cells in vitro. Therefore, novel therapeutic avenues that offer maximum benefits for the treatment of peripheral nerve injuries should be investigated. This review focused on strategies using mesenchymal stem cells to promote peripheral nerve regeneration including exosomes of mesenchymal stem cells, nerve engineering using the nerve guidance conduits containing mesenchymal stem cells, and genetically engineered mesenchymal stem cells. We present the current progress of mesenchymal stem cell treatment of peripheral nerve injuries.

Jab1 promotes gastric cancer tumorigenesis via non-ubiquitin proteasomal degradation of p14ARF.

BACKGROUND: Jab1 has been reported to regulate various proteins in signal transduction pathways and be implicated in carcinogenesis or tumor progression. However, the precise role and molecular mechanism of Jab1 in gastric tumorigenesis have not yet been fully elucidated. METHODS: Jab1 staining in gastric cancer tissues and paired non-cancerous tissues was measured using tissue microarray (TMA) technology. The impact of Jab1 on tumor growth in vivo was analyzed using xenotransplantation experiments in Balb/c mice. The expression of Jab1 and p14ARF in gastric cancer cells was analyzed by western blot and confocal immunofluorescence. CCK-8 and cell cycle experiment were used to evaluate the cell proliferation. Ubiquitination assay was performed to validate whether ubiquitination is involved in Jab1-mediated p14ARF degradation. RESULTS: The expression level of protein p14ARF was inversely correlated with the protein level of Jab1. Then, we investigated the mechanism that how Jab1 induced p14ARF depletion. Mechanistic studies showed that Jab1 induced ubiquitin-independent proteasomal p14ARF degradation in gastric cancer cells. Our data demonstrated that Jab1 protein was a vital upstream negative modulation factor of p14ARF, and Jab1 could promote cell proliferation and tumor growth via inhibiting the expression of p14ARF in vivo and in vitro. Moreover, silencing Jab1 protein expression declined tumor growth and further increased the apoptosis rate of gastric cancer cells. In further studies of gastric cancer specimens, we found the increased level of Jab1 protein shortened the overall survival. CONCLUSION: Jab1 is upstream of p14ARF and promote gastric cancer cell proliferation in vitro and in vivo. Furthermore, Jab1 decreased the expression of p14ARF though ubiquitination independent proteasomal degradation. Therefore, the connection of Jab1 and p14ARF may provide new methods for the treatment of gastric cancer.

Cadmium uptake, accumulation, and remobilization in iron plaque and rice tissues at different growth stages.

Rice consumption is considered the main source of human dietary Cd intake in Southeast Asia. This study aimed to investigate Cd uptake, accumulation, and remobilization in iron plaque and rice (Oryza sativa L. cv. 'Xiangwanxian 12') tissues at different growth stages. A pot experiment was performed in two Cd-contaminated paddy soils. Cd concentrations in iron plaque and rice tissues at five different growth stages (tillering, booting, milky, dough, and maturing) were measured. Cd concentrations in iron plaque and rice tissues (roots, stems, leaves, spikelet, husks, and brown rice) varied with growth stage. Cd accumulation in rice plants increased with extending growth in both soils, reaching 15.3 and 35.4µg/pot, respectively, at the maturing stage. The amounts of Cd in brown rice increased from the milky to maturing stages, with the greatest percentage uptake during the maturing stage. Cd amount in iron plaque significantly affected the uptake and accumulation of Cd in roots and aerial parts of rice plants. Accumulated Cd in leaves was remobilized and transported during the booting to maturing stages, and the contributions of Cd transportation from leaves to brown rice were 30.0% and 22.5% in the two soils, respectively. A large amount of Cd accumulated in brown rice during the maturing stage. The transportation of remobilized Cd from leaves was also important for the accumulation of Cd in brown rice.

Rap2a serves as a potential prognostic indicator of renal cell carcinoma and promotes its migration and invasion through up-regulating p-Akt.

Rap2a, a member of the small GTPase superfamily, belongs to Ras superfamily, and its function in cancer progression is still poorly understood. Our previous study indicated that the ectopic expression of Rap2a enhanced the migration and invasion ability of lung cancer cells. However, its expression and molecular mechanism on renal cell carcinoma (RCC) have not been characterized. This study explored the clinical significance and biological function of Rap2a in human RCC. The clinical relevance of Rap2a in RCC was evaluated by immunohistochemical staining using tissue microarray. Our data showed that Rap2a expression was dramatically increased in RCC tissues compared with normal renal tissues. The ectopic expression of Rap2a enhanced the migration and invasive ability of cancer cells. In contrast, downregulation of Rap2a inhibited cell invasion. Rap2a had no effect on the proliferation of RCC cell lines. Meanwhile, Rap2a can regulate the phosphorylation level of Akt in vitro. In vivo studies also showed that Rap2a positively regulated metastasis of renal cancer cells and the expression of p-Akt. These findings indicate that Rap2a promotes RCC metastasis and may serve as a candidate RCC prognostic marker and a potential therapeutic target.

[Impacts of Silicon Fertilizer as Base Manure on Cadmium Bioavailability in Soil and on Cadmium Accumulation in Rice Plants].

The impacts of silicon (Si) on cadmium (Cd) bioavailability in soil and Cd accumulation in rice plants were investigated in pot experiments with rice (Oryza sativa L.) cultivation. Silicon fertilizer as the base manure (Si 0, 15, 30, and 60 mg·kg-1) was added in simulated slightly Cd-contaminated soil (total soil Cd of 0.72 mg·kg-1) and severe Cd-contaminated soil (total soil Cd of 5.08 mg·kg-1). It indicated that the application of 15-60 mg·kg-1 Si before the rice was transplanted improved soil pH values and reduced the contents of exchangeable-Cd and TCLP extractable-Cd in the soil by 24.2%-43.7% and 12.7%-46.8%, respectively, during the rice growing stages. The reduction in soil Cd bioavailability resulted from the complexing of Si and Cd, and the reduction followed the order:slightly Cd-contaminated soil > severely Cd-contaminated soil. It was obvious that silicon fertilizer improved rice biomass above ground, especially for rice grain yield. In the slightly Cd-contaminated soil, Si both promoted and restrained soil Cd transportation from the rice root to the shoot; the low application (Si 15 mg·kg-1) and high application (Si 60 mg·kg-1) of Si both promoted Cd transportation, but the medium application (Si 30 mg·kg-1) restrained Cd transportation. With increasing silicon fertilizer application, Cd contents in brown rice increased first and then decreased, ranging from 0.07-0.15 mg·kg-1, remaining lower than 0.2 mg·kg-1. In the severely Cd-contaminated soil, Si restrained the soil Cd transportation from the rice root to the shoot. The Cd contents in brown rice, husk, and straw were reduced by 38.7%-48.5%, 35.7%-70.7%, and 30.9%-40.7%, respectively, and Cd contents in brown rice were 0.23-0.28 mg·kg-1. Considering rice grain yields and Cd contents in brown rice, it was recommended that the Si application be 30 mg·kg-1 of Si in the slightly Cd-contaminated soil and Si 15-60 mg·kg-1 in the severely Cd-contaminated soil.

Overexpression of p42.3 promotes cell proliferation, migration, and invasion in human gastric cancer cells.

As a newly discovered tumor-specific gene, p42.3 is overexpressed in most of human gastric cancers (GC). However, the role of p42.3 in GC progression remains unclear. To assess the role of p42.3 in gastric cancers, immunohistochemistry and western blot were performed to detect the p42.3 expression in human GC tissues and cells. We also investigated the role of p42.3 in GC cell proliferation, migration, and invasion. Our results showed that the p42.3 expression was increased dramatically in human GC tissue and cells. In addition, we found that overexpression of p42.3 promotes GC cell proliferation, migration, and invasion abilities. Furthermore, p42.3 expression suppressed the E-cadherin protein level and promoted the ß-catenin and p-ERK protein level. Taken together, overexpressed p42.3 is correlated with gastric cancer cell proliferation, migration, and invasion, suggesting its use as a biological marker in gastric cancer.

The diverse oncogenic and tumor suppressor roles of salt-inducible kinase (SIK) in cancer.

INTRODUCTION: The salt-inducible kinases originally cloned in adrenal glands of high salt diet-fed rats, generally named as SIKs, are highly evolutionarily conserved serine/threonine protein kinases belonging to a family of AMP-activated protein kinase (AMPK). Overexpression of SIK2 and SIK3 is discovered in many tumors. Whereas, SIK1 expression was significantly lower in tumors than in normal tissues. AREAS COVERED: The main aim of our review is to introduce the signaling pathways as well as its mechanisms underlying their activity regulation, and especially the roles they play in cancer, which may shed light on the prospects of the cancer prevention and therapeutic targeting of SIKs in the future. EXPERT OPINION: It is conceivable that SIKs, mainly stimulated by ACTH, LKB1, TGF-ß, and autophosphorylation, play crucial roles in regulating multiple signal pathways in cancer cells and controlling a series of cellular processes including cell proliferation and cell apoptosis. More recent studies about SIKs are emerging, and their overexpression is found in a few specific types of cancers. However, correlations between SIKs and carcinogenesis remain to be fully elucidated.

PLCε signaling in cancer.

PURPOSE: As one of the members of the PLC family, the phosphoinositide-specific phospholipase Cε (PLCε) has been shown to play pivotal roles in multiple signal pathways and control a variety of cellular functions. A number of studies have shown that aberrant regulation of PLCε was involved in various types of animal and human cancer. However, the role of PLCε in cancer remains elusive. In this review, we provide an overview of the PLCε, especially its roles in multiple signal pathways, and summarize the recent findings that highlight the roles of PLCε in carcinogenesis and cancer progression, making an avenue to provide a novel therapeutic strategy for the treatment of cancer. METHODS: A literature search mainly paying attention to the network of PLCε involved in tumorigenesis and development was performed in electronic databases. RESULTS: PLCε plays a key role in medicating the development and progression of human cancers with highest potency to be a target of cancer prevention and treatment.

Suppression of CSN5 promotes the apoptosis of gastric cancer cells through regulating p53-related apoptotic pathways.

As one of the COP9 signalosome complex, CSN5 (also known as Jab1) has been confirmed overexpression in many human cancers and affected multiple pathways associating with cell proliferation and apoptosis. Correlation of CSN5 overexpression with poor prognosis for cancer provides evidence that it is involved in the tumorigenesis. However, little is known about the functional role and the underlying mechanism of CSN5 in gastric cancer progression. In the current study, the effect of CSN5 siRNA (small-interfering RNA) on the proliferation and apoptosis of human gastric cancer cells (AGS and MKN45) were examined. Our results showed that knockdown of CSN5 could inhibit proliferation and promote apoptosis of gastric cancer cells. Additionally, suppression of CSN5 expression contributed to the increased expression levels of p53 and Bax. In conclusion, CSN5 overexpression is significantly correlated with gastric cancer progression, and CSN5 could be a novel target in gastric cancer therapy.