Depleting IFIT2 mediates atypical PKC signaling to enhance the migration and metastatic activity of oral squamous cell carcinoma cells

Sequence Diversity in the 3' Untranslated Region of Alphavirus Modulates IFIT2-Dependent Restriction in a Cell Type-Dependent Manner

Alphaviruses (family Togaviridae) are a diverse group of positive-sense RNA (+ssRNA) viruses that are transmitted by arthropods and are the causative agent of several significant human and veterinary diseases. Interferon (IFN)-induced proteins with tetratricopeptide repeats (IFITs) are a family of RNA-binding IFN-stimulated genes (ISGs) that are highly upregulated following viral infection and have been identified as potential restrictors of alphaviruses. The mechanism by which IFIT1 restricts RNA viruses is dependent on self and non-self-discrimination of RNA, and alphaviruses evade this recognition via their 5' untranslated region (UTR). However, the role of IFIT2 during alphavirus replication and the mechanism of viral replication inhibition is unclear. In this study, we identify IFIT2 as a restriction factor for Venezuelan equine encephalitis virus (VEEV) and show that IFIT2 binds the 3' 3'UTR of the virus. We investigated the potential role of variability in the 3'UTR of the virus affecting IFIT2 antiviral activity by studying infection with VEEV. Comparison of recombinant VEEV clones containing 3'UTR sequences derived from epizootic and enzootic isolates exhibited differential sensitivity to IFIT2 restriction in vitro infection studies, suggesting that the alphavirus 3'UTR sequence may function in part to evade IFIT2 restriction. In vitro binding assays demonstrate that IFIT2 binds to the VEEV 3'UTR; however, in contrast to previous studies, VEEV restriction did not appear to be dependent on the ability of IFIT2 to inhibit translation of viral RNA, suggesting a novel mechanism of IFIT2 restriction. Our study demonstrates that IFIT2 is a restriction factor for alphaviruses and variability in the 3'UTR of VEEV can modulate viral restriction by IFIT2. Ongoing studies are exploring the biological consequences of IFIT2-VEEV RNA interaction in viral pathogenesis and defining sequence and structural features of RNAs that regulate IFIT2 recognition.

miR-19a may function as a biomarker of oral squamous cell carcinoma (OSCC) by regulating the signaling pathway of miR-19a/GRK6/GPCRs/PKC in a Chinese population

BACKGROUND

In this study, we aimed to investigate the potential of miR-19a as a biomarker of OSCC and its underlying molecular mechanisms.

METHODS

We collected serum and saliva samples from 66 OSCC patients and 66 healthy control subjects. Real-time PCR analysis, bioinformatic analysis and luciferase assays were performed to establish a potential signaling pathway of miR-19a/GRK6/GPCRs/PKC. Flowcytometry and Transwell assays were performed to observe the changes in cell apoptosis, metastasis and invasion.

RESULTS

We found that miR-19a, GPR39 mRNA and PKC mRNA were upregulated while GRK6 mRNA was downregulated in the serum and saliva samples collected from OSCC patients. Moreover, in silico analysis confirmed a potential binding site of miR-19a on the 3'UTR of GRK6 mRNA, and the subsequent luciferase assays confirmed the molecular binding between GRK6 and miR-19a. We further identified that the over-expression of miR-19a could regulate the signaling between GRK6, GPR39 and PKC via the signaling pathway of miR-19a/GRK6/GPR39/PKC, which accordingly resulted in suppressed cell apoptosis and promoted cell migration and invasion.

CONCLUSION

Collectively, the findings of our study propose that miR-19a is a crucial mediator in the advancement of OSCC, offering a potential avenue for the development of innovative therapeutic interventions aimed at regulating GRK6 and its downstream signaling pathways.

MicroRNAs as the pivotal regulators of cisplatin resistance in osteosarcoma

Osteosarcoma (OS) is an aggressive bone tumor that originates from mesenchymal cells. It is considered as the eighth most frequent childhood cancer that mainly affects the tibia and femur among the teenagers and young adults. OS can be usually diagnosed by a combination of MRI and surgical biopsy. The intra-arterial cisplatin (CDDP) and Adriamycin is one of the methods of choices for the OS treatment. CDDP induces tumor cell death by disturbing the DNA replication. Although, CDDP has a critical role in improving the clinical complication in OS patients, a high ratio of CDDP resistance is observed among these patients. Prolonged CDDP administrations have also serious side effects in normal tissues and organs. Therefore, the molecular mechanisms of CDDP resistance should be clarified to define the novel therapeutic modalities in OS. Multidrug resistance (MDR) can be caused by various cellular and molecular processes such as drug efflux, detoxification, and signaling pathways. MicroRNAs (miRNAs) are the key regulators of CDDP response by the post transcriptional regulation of target genes involved in MDR. In the present review we have discussed all of the miRNAs associated with CDDP response in OS cells. It was observed that the majority of reported miRNAs increased CDDP sensitivity in OS cells through the regulation of signaling pathways, apoptosis, transporters, and autophagy. This review highlights the miRNAs as reliable non-invasive markers for the prediction of CDDP response in OS patients.

Ifit2 restricts murine coronavirus spread to the spinal cord white matter and its associated myelin pathology

Interferon-induced protein with tetratricopeptide repeats 2, Ifit2, is critical in restricting neurotropic murine-β-coronavirus, RSA59 infection. RSA59 intracranial injection of Ifit2-deficient (-/-) compared to wild-type (WT) mice results in impaired acute microglial activation, reduced CX3CR1 expression, limited migration of peripheral lymphocytes into the brain, and impaired virus control followed by severe morbidity and mortality. While the protective role of Ifit2 is established for acute viral encephalitis, less is known about its influence during the chronic demyelinating phase of RSA59 infection. To understand this, RSA59 infected Ifit2-/- and Ifit2+/+ (WT) were observed for neuropathological outcomes at day 5 (acute phase) and 30 post-infection (chronic phase). Our study demonstrates that Ifit2 deficiency causes extensive RSA59 spread throughout the spinal cord gray and white matter, associated with impaired CD4+ T and CD8+ T cell infiltration. Further, the cervical lymph nodes of RSA59 infected Ifit2-/- mice showed reduced activation of CD4+ T cells and impaired IFNγ expression during acute encephalomyelitis. Interestingly, BBB integrity was better preserved in Ifit2-/- mice, as evidenced by tight junction protein Claudin-5 and adapter protein ZO-1 expression surrounding the meninges and blood vessels and decreased Texas red dye uptake, which may be responsible for reduced leukocyte infiltration. In contrast to sparse myelin loss in WT mice, the chronic disease phase in Ifit2-/- mice was associated with severe demyelination and persistent viral load, even at low inoculation doses. Overall, our study highlights that Ifit2 provides antiviral functions by promoting acute neuroinflammation and thereby aiding virus control and limiting severe chronic demyelination. IMPORTANCE Interferons execute their function by inducing specific genes collectively termed as interferon-stimulated genes (ISGs), among which interferon-induced protein with tetratricopeptide repeats 2, Ifit2, is known for restricting neurotropic viral replication and spread. However, little is known about its role in viral spread to the spinal cord and its associated myelin pathology. Toward this, our study using a neurotropic murine β-coronavirus and Ifit2-deficient mice demonstrates that Ifit2 deficiency causes extensive viral spread throughout the gray and white matter of the spinal cord accompanied by impaired microglial activation and T cell infiltration. Furthermore, infected Ifit2-deficient mice showed impaired activation of T cells in the cervical lymph node and relatively intact blood-brain barrier integrity. Overall, Ifit2 plays a crucial role in mounting host immunity against neurotropic murine coronavirus in the acute phase while preventing mice from developing viral-induced severe chronic neuroinflammatory demyelination, the characteristic feature of human neurological disease multiple sclerosis (MS).

IFIT2 Depletion Promotes Cancer Stem Cell-like Phenotypes in Oral Cancer

(1) Background: Cancer stem cells (CSCs) are a small cell population associated with chemoresistance, metastasis and increased mortality rate in oral cancer. Interferon-induced proteins with tetratricopeptide repeats 2 (IFIT2) depletion results in epithelial to mesenchymal transition, invasion, metastasis, and chemoresistance in oral cancer. To date, no study has demonstrated the effect of IFIT2 depletion on the CSC-like phenotype in oral cancer cells. (2) Methods: Q-PCR, sphere formation, Hoechst 33,342 dye exclusion, immunofluorescence staining, and flow cytometry assays were performed to evaluate the expression of the CSC markers in IFIT2-depleted cells. A tumorigenicity assay was adopted to assess the tumor formation ability. Immunohistochemical staining was used to examine the protein levels of IFIT2 and CD24 in oral cancer patients. (3) Results: The cultured IFIT2 knockdown cells exhibited an overexpression of ABCG2 and CD44 and a downregulation of CD24 and gave rise to CSC-like phenotypes. Clinically, there was a positive correlation between IFIT2 and CD24 in the patients. IFIT2high/CD24high/CD44low expression profiles predicted a better prognosis in HNC, including oral cancer. The TNF-α blockade abolished the IFIT2 depletion-induced sphere formation, indicating that TNF-α may be involved in the CSC-like phenotypes in oral cancer. (4) Conclusions: The present study demonstrates that IFIT2 depletion promotes CSC-like phenotypes in oral cancer.

How Different Pathologies Are Affected by IFIT Expression

The type-I interferon (IFN) system represents the first line of defense against viral pathogens. Recognition of the virus initiates complex signaling pathways that result in the transcriptional induction of IFNs, which are then secreted. Secreted IFNs stimulate nearby cells and result in the production of numerous proinflammatory cytokines and antiviral factors. Of particular note, IFN-induced tetratricopeptide repeat (IFIT) proteins have been thoroughly studied because of their antiviral activity against different viral pathogens. Although classically studied as an antiviral protein, IFIT expression has recently been investigated in the context of nonviral pathologies, such as cancer and sepsis. In oral squamous cell carcinoma (OSCC), IFIT1 and IFIT3 promote metastasis, while IFIT2 exhibits the opposite effect. The role of IFIT proteins during bacterial/fungal sepsis is still under investigation, with studies showing conflicting roles for IFIT2 in disease severity. In the setting of viral sepsis, IFIT proteins play a key role in clearing viral infection. As a result, many viral pathogens, such as SARS-CoV-2, employ mechanisms to inhibit the type-I IFN system and promote viral replication. In cancers that are characterized by upregulated IFIT proteins, medications that decrease IFIT expression may reduce metastasis and improve survival rates. Likewise, in cases of viral sepsis, therapeutics that increase IFIT expression may improve viral clearance and reduce the risk of septic shock. By understanding the effect of IFIT proteins in different pathologies, novel therapeutics can be developed to halt disease progression.

Identification of circRNA-lncRNA-miRNA-mRNA competitive endogenous RNA networks as prognostic bio-markers in head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is one of the most prevalent neoplasms of malignancy. The pathogenesis of HNSCC is involved in the change of gene expression and the abnormal interaction between genes.

OBJECTIVE

The purpose of our research is to find genes that affect the survival time of patients and construct circRNA-lncRNA-miRNA-mRNA network. This paper aims to reveal the development mechanism of HNSCC and provide new ideas for clinical prognosis prediction.

METHODS

Transcriptome data were obtained from TCGA and GEO databases. A total of 556 samples were included. We screened the differentially expressed lncRNAs, circRNAs and mRNAs to predict interactions between lncRNA-miRNA, circRNA-miRNA and miRNA-mRNA. Then, we selected the hub mRNAs to predict the prognosis of patients.

RESULTS

We identified 8 hub prognostic mRNAs (FAM111A, IFIT2, CAV1, KLF9, OCIAD2, SLCO3A1, S100A16 and APOL3) by a series of bioinformatics analyses and established the prognostic ceRNA network of 8 mRNAs, 3 miRNAs, 2 circRNAs and 1 lncRNAs according to the targeting relationship by using databases.

CONCLUSION

We established the circRNA-lncRNA-miRNA-mRNA gene interaction network in HNSCC. We illuminated the molecular mechanism underlying the gene regulation associated with the pathogenesis of HNSCC and predicted the biomarkers related to prognosis.

Bioactive glass selectively promotes cytotoxicity towards giant cell tumor of bone derived neoplastic stromal cells and induces MAPK signalling dependent autophagy

Giant cell tumors of bone (GCTB) are associated with massive bone destructions and high recurrence rates. In a previous study, we observed cytotoxic effects of three different compositions of bioactive glasses (BGs) towards GCTSC but not bone marrow derived stromal cells (BMSC) indicating that BGs represent promising candidates for the development of new therapeutic approaches. In the current study we aimed to investigate the molecular mechanisms that are involved in BG induced cytotoxicity. We observed, that BG treatment was not associated with any signs of apoptosis, but rather led to a strong induction of mitogen activated protein kinases (MAPK) and, as a consequence, upregulation of several transcription factors specifically in GCTSC. Genome wide gene expression profiling further revealed a set of fifteen genes that were exclusively induced in GCTSC or induced significantly stronger in GCTSC compared to BMSC. BG treatment further induced autophagy that was significantly more pronounced in GCTSC compared to BMSC and could be inhibited by MAPK inhibitors. Together with the known osteogenic properties of BGs our findings support the suitability of BGs as therapeutic agents for the treatment of GCTB. However, these data have to be verified under in vivo conditions.

•

Bioactive glasses (BG) are selectively cytotoxic towards neoplastic stromal cells.

•

BG induced cell death is independent from apoptosis.

•

BG activates mitogen activated protein kinases and transcription factors.

•

BG trigger differential gene expression in neoplastic versus normal cells.

•

BG induce autophagy.

Hypermethylation of PRKCZ Regulated by E6 Inhibits Invasion and EMT via Cdc42 in HPV-Related Head and Neck Squamous Cell Carcinoma

Purpose: To study the role of target genes with aberrant DNA methylation in HPV+ HNSCC. Methods: A HumanMethylation450 BeadChip array (Illumina) was used to identify differentially methylated genes. CCK-8, flow cytometry, wound healing, and cell invasion assays were conducted to analyze the biological roles of PRKCZ. Western blot, qRT-PCR, immunohistochemistry, and animal studies were performed to explore the mechanisms underlying the functions of PRKCZ. Results: We selected PRKCZ, which is associated with HPV infection, as our target gene. PRKCZ was hypermethylated in HPV+ HNSCC patients, and PRKCZ methylation status was negatively related to the pathological grading of HNSCC patients. Silencing PRKCZ inhibited the malignant capacity of HPV+ HNSCC cells. Mechanistically, HPV might promote DNMT1 expression via E6 to increase PRKCZ methylation. Cdc42 was required for the PRKCZ-mediated mechanism of action, contributing to the occurrence of epithelial-mesenchymal transition (EMT) in HPV+ HNSCC cells. In addition, blocking PRKCZ delayed tumor growth in HPV16-E6/E7 transgenic mice. Cdc42 expression was decreased, whereas E-cadherin levels increased. Conclusion: We suggest that PRKCZ hypermethylation induces EMT via Cdc42 to act as a potent tumor promoter in HPV+ HNSCC.

STAT1/IFIT2 signaling pathway is involved in PD-L1-mediated epithelial-to-mesenchymal transition in human esophageal cancer

Background

We have previously reported significant change of epithelial to mesenchymal transition (EMT) phenotype of Eca-109 cells upon PD-L1 operation, and the cytoplasmic domain of PD-L1 played an essential role in promoting EMT of esophageal cancer cells. However, the underlying mechanism of how PD-L1 regulated EMT in esophageal cancer remained unclear.

Methods

The overexpression and knockdown expression models of PD-L1 and IFIT2 were established by using lenti-virus transfection and RNAi method. Western blotting, qRT-PCR, CCK8 assay, transwell assay and wound healing assay were chosen to investigate their impact on the cells. The expression levels of IFIT2 and EMT markers in esophageal cancer tissues were examined by immunohistochemical staining. The rescue experiments were further applied to investigate the role of STAT1/IFIT2 signal pathway in the PD-L1-mediated EMT. Luciferase reporter assays were performed to examine the IFIT2 promoter activities upon knockdown expression of PD-L1 to identify the putative targeted region of IFIT2 promoter.

Results

The STAT1/IFIT2 signal pathway was activated when PD-L1 was knockdown in human esophageal cancer cells. Decreased IFIT2 expression significantly increased the cellular abilities of viability, invasion and migration by using RNAi method in human esophageal cancer cells. Decreased IFIT2 expression in esophageal cancer tissues significantly correlated with EMT status, and could be used as an independent prognostic predictor for the patients. Rescue experiments in PD-L1 knockdown cells further confirmed that STAT1/IFIT2 pathway was involved in the PD-L1 mediated EMT of esophageal cancer cells. Moreover, the luciferase reporter assay also confirmed that in esophageal cancer cells, the promoter region of IFIT2 (-3K~-1K) remains more active in PD-L1 knockdown expression cells compared with controls.

Conclusion

Our present work reveals a novel mechanism of how PD-L1 regulates EMT of cancer cells, namely STAT1/IFIT2 signal pathway is required in PD-L1 mediated EMT in human esophageal cancer.

IFIT2-depleted metastatic oral squamous cell carcinoma cells induce muscle atrophy and cancer cachexia in mice

BACKGROUND

Interferon-induced protein with tetratricopeptide repeat 2 (IFIT2) is a reported metastasis suppressor in oral squamous cell carcinoma (OSCC). Metastases and cachexia may coexist. The effect of cancer metastasis on cancer cachexia is largely unknown. We aimed to address this gap in knowledge by characterizing the cachectic phenotype of an IFIT2-depleted metastatic OSCC mouse model.

METHODS

Genetically engineered and xenograft tumour models were used to explore the effect of IFIT2-depleted metastatic OSCC on cancer cachexia. Muscle and organ weight changes, tumour burden, inflammatory cytokine profiles, body composition, food intake, serum albumin and C-reactive protein (CRP) levels, and survival were assessed. The activation of the IL6/p38 pathway in atrophied muscle was measured.

RESULTS

IFIT2-depleted metastatic tumours caused marked body weight loss (-18.2% vs. initial body weight, P < 0.001) and a poor survival rate (P < 0.01). Skeletal muscles were markedly smaller in IFIT2-depleted metastatic tumour-bearing mice (quadriceps: -28.7%, gastrocnemius: -29.4%, and tibialis: -24.3%, all P < 0.001). Tumour-derived circulating granulocyte-macrophage colony-stimulating factor (+772.2-fold, P < 0.05), GROα (+1283.7-fold, P < 0.05), IL6 (+245.8-fold, P < 0.001), IL8 (+616.9-fold, P < 0.001), IL18 (+24-fold, P < 0.05), IP10 (+18.8-fold, P < 0.001), CCL2 (+439.2-fold, P < 0.001), CCL22 (+9.1-fold, P < 0.01) and tumour necrosis factor α (+196.8-fold, P < 0.05) were elevated in IFIT2-depleted metastatic tumour-bearing mice. Murine granulocyte colony-stimulating factor (+61.4-fold, P < 0.001) and IL6 (+110.9-fold, P < 0.01) levels were significantly increased in IFIT2-depleted metastatic tumour-bearing mice. Serum CRP level (+82.1%, P < 0.05) was significantly increased in cachectic shIFIT2 mice. Serum albumin level (-26.7%, P < 0.01) was significantly decreased in cachectic shIFIT2 mice. An assessment of body composition revealed decreased fat (-81%, P < 0.001) and lean tissue (-21.7%, P < 0.01), which was consistent with the reduced food intake (-19.3%, P < 0.05). Muscle loss was accompanied by a smaller muscle cross-sectional area (-23.3%, P < 0.05). Muscle atrophy of cachectic IFIT2-depleted metastatic tumour-bearing mice (i.v.-shIFIT2 group) was associated with elevated IL6 (+2.7-fold, P < 0.05), phospho-p38 (+2.8-fold, P < 0.05), and atrogin-1 levels (+2.3-fold, P < 0.05) in the skeletal muscle. Neutralization of IL6 rescued shIFIT2 conditioned medium-induced myotube atrophy (+24.6%, P < 0.01).

CONCLUSIONS

Our results suggest that the development of shIFIT2 metastatic OSCC lesions promotes IL6 production and is accompanied by the loss of fat and lean tissue, anorexia, and muscle atrophy. This model is appropriate for the study of OSCC cachexia, especially in linking metastasis with cachexia.

Knockdown of NAA25 Suppresses Breast Cancer Progression by Regulating Apoptosis and Cell Cycle

NAA25 gene variants were reported as risk factors for type 1 diabetes, rheumatoid arthritis and acute arterial stroke. But it’s unknown whether it could contribute to breast cancer. We identified rs11066150 in lncHSAT164, which contributes to breast cancer, in our earlier genome-wide long non-coding RNA association study on Han Chinese women. However, rs11066150 A/G variant is also located in NAA25 intron. Based on the public database, such as TCGA and Curtis dataset, NAA25 gene is highly expressed in breast cancer tissues and this result has also been proved in our samples and cell lines through RT-qPCR and western blot analysis. To better understand the function of NAA25 in breast cancer, we knocked down the expression of NAA25 in breast cancer cell lines, FACS was used to detect cell apoptosis and cell cycle and colony formation assay was used to detect cell proliferation. We found that NAA25-deficient cells could increase cell apoptosis, delay G2/M phase cell and decrease cell clone formation. RNA sequencing was then applied to analyze the molecular profiles of NAA25−deficient cells, and compared to the control group, NAA25 knockdown could activate apoptosis-related pathways, reduce the activation of tumor-associated signaling pathways and decrease immune response-associated pathways. Additionally, RT-qPCR was employed to validate these results. Taken together, our results revealed that NAA25 was highly expressed in breast cancer, and NAA25 knockdown might serve as a therapeutic target in breast cancer.

METTL3 promotes intrahepatic cholangiocarcinoma progression by regulating IFIT2 expression in an m6A-YTHDF2-dependent manner

N6-methyladenosine (m6A) RNA methylation has recently been found involving in regulatory mechanism of the tumor progression. Our aim was to explore the biological function and clinical significance of the m6A methyltransferase METTL3 in intrahepatic cholangiocarcinoma (ICC). In this study, we revealed that METTL3 was upregulated and predicted poor prognosis of patients with ICC. Multivariate regression analysis demonstrated that METTL3 expression was an independent predictor for overall survival in patients with ICC. Moreover, METTL3 knockdown inhibited ICC progression, while METTL3 overexpression showed the opposite effect. METTL3 inhibitor STM2457 also showed anti-tumor effect in ICC. Mechanistically, METTL3 transcription was driven by H3K4me3 activation. Upregulation of METTL3 mediated m6A modification of IFIT2 mRNA and accelerated IFIT2 mRNA decay in a YTHDF2-dependent manner, which promoted the development of ICC and lead to poorer prognosis. In summary, our findings revealed that H3K4me3 activation-driven METTL3 transcription promotes ICC progression by YTHDF2-mediated IFIT2 mRNA degradation, suggesting that METTL3 may serve as a potential target for human ICC therapy.

Comprehensive analysis of the prognosis and biological significance for IFIT family in skin cutaneous melanoma

Interferon-induced protein with tetratricopeptide repeats (IFITs) genes, consisting of four members named IFIT1, IFIT2, IFIT3 and IFIT5, are involved in the progression of multiple cancer types, but their roles in skin cutaneous melanoma (SKCM) are still largely unknown. The TCGA-SKCM dataset, GSE15605 dataset and GSE100508 dataset were obtained in our study, and multiple online databases were used for data analysis and visualization, including GEPIA, GSCALite, MethSurv, DAVID, starBase and TIMER database. The mRNA expressing levels of all the four members included in IFIT family were elevated in SKCM tissues. In addition, ROC curve showed that the combined IFITs had a higher tumor prediction performance. Kaplan-Meier survival analysis revealed that the low expression of IFIT1/2/3/5 was associated with poor overall survival (OS) and disease-specific survival (DSS) in SKCM patients. Moreover, univariate and multivariate Cox regression analysis suggested that the low expression of IFIT2/3/5 was an independent risk factor for the prognosis of SKCM patients. Besides, cancer pathway activity analysis certified that the IFITs were involved in the apoptosis pathways, epithelial-mesenchymal transition (EMT) and cell cycle. Furthermore, drug sensitivity analysis indicated that the high expression of IFIT1/2/3 was sensitive to dasatinib drug. Additionally, the expressing levels of IFITs were found to be positively correlated with the level of immune cell infiltrates, immune biomarkers and m6A regulators. Finally, using bioinformatics analysis, we predicted that PAX8-AS1/Z83843.1-miR-92a-3p-IFIT2 axis might play crucial roles in the development and progression of SKCM. This study explored the prognostic values and biological significance of the IFITs in SKCM microenvironment. IFITs may serve as novel biomarkers for the diagnosis and prognosis of melanoma and potential immunotherapeutic targets.

A novel melatonin-regulated lncRNA suppresses TPA-induced oral cancer cell motility through replenishing PRUNE2 expression

The inhibitory effect of melatonin on cancer cell dissemination is well established, yet the functional involvement of lncRNAs in melatonin signaling remains poorly understood. In this study, we identified a melatonin-attenuated lncRNA acting as a potential melatonin-regulated oral cancer stimulator (MROS-1). Downregulation of MROS-1 by melatonin suppressed TPA-induced oral cancer migration through replenishing the protein expression of prune homolog 2 (PRUNE2), which functioned as a tumor suppressor in oral cancer. Melatonin-mediated MROS-1/PRUNE2 expression and cell motility in oral cancer were regulated largely through the activation of JAK-STAT pathway. In addition, MROS-1, preferentially localized in the nuclei, promoted oral cancer migration in an epigenetic mechanism in which it modulates PRUNE2 expression by interacting with a member of the DNA methylation machinery, DNA methyltransferase 3A (DNMT3A). Higher methylation levels of PRUNE2 promoter were associated with nodal metastases and inversely correlated with PRUNE2 expression in head and neck cancer. Collectively, these findings suggest that MROS-1, serving as a functional mediator of melatonin signaling, could predispose patients with oral cancer to metastasize and may be implicated as a potential target for antimetastatic therapies.

Putative role of natural products as Protein Kinase C modulator in different disease conditions

INTRODUCTION

Protein kinase C (PKC) is a promising drug target for various therapeutic areas. Natural products derived from plants, animals, microorganisms, and marine organisms have been used by humans as medicine from prehistoric times. Recently, several compounds derived from plants have been found to modulate PKC activities through competitive binding with ATP binding site, and other allosteric regions of PKC. As a result fresh race has been started in academia and pharmaceutical companies to develop an effective naturally derived small-molecule inhibitor to target PKC activities. Herein, in this review, we have discussed several natural products and their derivatives, which are reported to have an impact on PKC signaling cascade.

METHODS

All information presented in this review article regarding the regulation of PKC by natural products has been acquired by a systematic search of various electronic databases, including ScienceDirect, Scopus, Google Scholar, Web of science, ResearchGate, and PubMed. The keywords PKC, natural products, curcumin, rottlerin, quercetin, ellagic acid, epigallocatechin-3 gallate, ingenol 3 angelate, resveratrol, protocatechuic acid, tannic acid, PKC modulators from marine organism, bryostatin, staurosporine, midostaurin, sangivamycin, and other relevant key words were explored.

RESULTS

The natural products and their derivatives including curcumin, rottlerin, quercetin, ellagic acid, epigallocatechin-3 gallate, ingenol 3 angelate, resveratrol, bryostatin, staurosporine, and midostaurin play a major role in the management of PKC activity during various disease progression.

CONCLUSION

Based on the comprehensive literature survey, it could be concluded that various natural products can regulate PKC activity during disease progression. However, extensive research is needed to circumvent the challenge of isoform specific regulation of PKC by natural products.

Super-enhancer-associated long noncoding RNA RP11-569A11.1 inhibited cell progression and metastasis by regulating IFIT2 in colorectal cancer

BACKGROUND

Recent studies have revealed that super-enhancer-associated long noncoding RNAs (SE-LncRNAs) act pivotal roles in carcinogenesis. This study aimed to report the identification of a novel SE-LncRNA, RP11-569A11.1, and its functional role in colorectal cancer (CRC) progression.

METHODS

Arraystar human SE-LncRNA microarray was performed to detect differentially expressed SE-LncRNAs in CRC tissues. RT-qPCR was conducted to detect the expression level of RP11-569A11.1 in CRC tissues and cells. The ROC curve was used to analyze the sensitivity and specificity of RP11-569A11.1 in CRC diagnosis. CCK-8 assay, colony formation assay, flow cytometry assay, and transwell assay were used to study the function of RP11-569A11.1. RNA-seq array was performed to analyze the potential downstream target gene of RP11-569A11.1. Western blot assay was conducted to measure the protein level of interferon-induced protein with tetratricopeptide repeat 2 (IFIT2).

RESULTS

A total of 23 (15 up- and 8 downregulated) significantly expressed SE-LncRNAs were identified in CRC tissues. The top 8 upregulated SE-LncRNAs were RP11-893F2.9, PTCSC1, RP11-803D5.4, AC005592.2, LINC00152, LINC01232, AC017002.1, and RP4-673M15.1, and the top 8 downregulated SE-LncRNAs were RP11-569A11.1, RP11-245G13.2, RP11-556N21.1, U91328.19, AX748340, CTD-2337J16.1, CATG00000108830.1, and RP11-670E13.2. Of which, RP11-569A11.1 was found to be significantly downregulated in CRC tissues and cells. ROC curve analysis showed the area under the curve (AUC) of 0.77 [95% confidence interval (CI), 0.660-0.884, p < 0.001], and the diagnostic sensitivity and specificity were 74.29% and 71.43%, respectively. Functionally, overexpression of RP11-569A11.1 inhibited CRC cell proliferation, migration and invasion, and induced cell apoptosis, while knockdown of RP11-569A11.1 generated an opposite effect. Mechanistically, RP11-569A11.1 positively regulated IFIT2 expression in CRC cells.

CONCLUSION

RP11-569A11.1 inhibited CRC tumorigenesis by IFIT2-dependent and could serve as a promising diagnostic biomarker in CRC.

The impact of indole-3-lactic acid on immature intestinal innate immunity and development: a transcriptomic analysis

An excessive intestinal inflammatory response may have a role in the pathogenesis of necrotizing enterocolitis (NEC) in very preterm infants. Indole-3-lactic acid (ILA) of breastmilk tryptophan was identified as the anti-inflammatory metabolite involved in probiotic conditioned media from Bifidobacteria longum subsp infantis. This study aimed to explore the molecular endocytic pathways involved in the protective ILA effect against inflammation. H4 cells, Caco-2 cells, C57BL/6 pup and adult mice were used to compare the anti-inflammatory mechanisms between immature and mature enterocytes in vitro and in vivo. The results show that ILA has pleiotropic protective effects on immature enterocytes including anti-inflammatory, anti-viral, and developmental regulatory potentials in a region-dependent and an age-dependent manner. Quantitative transcriptomic analysis revealed a new mechanistic model in which STAT1 pathways play an important role in IL-1β-induced inflammation and ILA has a regulatory effect on STAT1 pathways. These studies were validated by real-time RT-qPCR and STAT1 inhibitor experiments. Different protective reactions of ILA between immature and mature enterocytes indicated that ILA's effects are developmentally regulated. These findings may be helpful in preventing NEC for premature infants.

Proteomic Alterations Associated with Oral Cancer Patients with Tobacco Using Habits

Tobacco abuse is a major risk factor associated with the development of oral squamous cell carcinoma. Differences in molecular aberrations induced by tobacco exposure by chewing or smoking form are not well studied in case of oral cancer. We used tandem mass tag-based quantitative proteomic approach to delineate proteomic alterations in oral cancer patients based on their history of tobacco using habits (patients who chewed tobacco, patients who smoked tobacco, and those with no history of tobacco consumption). Our data identified distinct dysregulation of biological processes and pathways in each patient cohort. Bioinformatics analysis of dysregulated proteins identified in our proteomic study revealed dysregulation of collagen formation and antigen processing/presentation pathway in oral cancer patients who smoked tobacco, whereas proteins associated with the process of keratinization showed enrichment in patients who chewed tobacco. In addition, we identified overexpression of proteins involved in immune pathways and downregulation of muscle contraction-mediated signaling events in all three cohorts, irrespective of tobacco using habits. This study lays the groundwork for identification of protein markers that may aid in identification of high-risk patients for cancer development based on the history of tobacco exposure habits.

Long Non-coding RNAs in Cisplatin Resistance in Osteosarcoma

OPINION STATEMENT

Osteosarcoma (OS), the most common primary malignant bone tumor, is a vastly aggressive disease in children and adolescents. Although dramatic progress in therapeutic strategies have achieved over the past several decades, the outcome remains poor for most patients with metastatic or recurrent OS. Nowadays, conventional treatment for OS patients is surgery combined with multidrug chemotherapy including doxorubicin, methotrexate, and cisplatin (CDDP). In this sense, cisplatin (CDDP) is one of the most drugs used in the treatment of OS but drug resistance to CDDP appears as a serious problem in the use of this drug in the treatment of OS. Thus, we consider that the understanding the molecular mechanisms and the genes involved that lead to CDDP resistance is essential to developing more effective treatments against OS. In this review, we present an outline of the key role of the long non-coding RNAs (lncRNAs) in CDDP resistance in OS. This overview is expected to contribute to understand the mechanisms of CDDP resistance in OS and the relationship of the expression regulation of several lncRNAs.

Transcriptome analysis reveals possible antitumor mechanism of Chlorella exopolysaccharide

Microalgae, one of the most important classes of biomass producers, can produce exopolysaccharides similar to bacteria. The exopolysaccharide from Chlorella (CEPS) displays remarkable anticancer activity the mechanism of which remains to be elucidated. In this study, we analyzed the inhibitory effect of CEPS on the growth of HeLa cells. The results showed that CEPS inhibited the proliferation, decreased the viability, and changed the morphology of HeLa cells. Transcriptome analysis showed that 1894 genes were differentially expressed in the CEPS-treated group compared with the control group, including 1076 genes that were upregulated and 818 genes that were downregulated. The results of gene function enrichment analysis showed that the differentially expressed genes (DEGs) were significantly enriched in apoptosis and tumor-related biological processes and participated in several cancer and apoptosisrelated signaling pathways, including the MAPK signaling pathway, TNF signaling pathway, and the PI3K-Akt signaling pathway. The protein-protein interaction network identified 13 DEGs including PTPN11, RSAD2, ISG15, IFIT1, MX2, IFIT2, OASL, OAS1, JUN, OAS2, XAF1, ISG20, and IRF9 as hub genes. Our results suggest that CEPS is a promising therapeutic drug for the follow-up interventional therapy of cancer.

SAHA Overcomes 5-FU Resistance in IFIT2-Depleted Oral Squamous Cell Carcinoma Cells

Simple Summary

IFIT2 depletion is associated with increased epithelial-mesenchymal transition and metastasis. The main aim of our study was to understand the link between drug resistance and IFIT2 depletion. In this study, we confirmed resistance to multiple common therapeutic drugs, particularly 5-FU, which showed especially high resistance in IFIT2-depleted cells. Interestingly, combination of SAHA and 5-FU overcame 5-FU resistance in IFIT2-depleted cells. Hence, our findings suggest that IFIT2 expression may be used as a biomarker to decide whether to undergo 5-FU treatment, but also the SAHA and 5-FU combination may be a potential new treatment regimen to augment 5-FU therapy in patients with thymidylate synthase-mediated drug-resistant oral squamous cell carcinoma.

Abstract

Interferon-induced protein with tetratricopeptide repeats 2 (IFIT2) is a member of the interferon-stimulated gene family that contains tetratricopeptide repeats (TPRs), which mediate protein–protein interactions in various biological systems. We previously showed the depletion of IFIT2 enhanced cell migration and metastatic activity in oral squamous cell carcinoma (OSCC) cells via the activation of atypical PKC signaling. In this study, we found that IFIT2-knockdown cells displayed higher resistance to 5-fluorouracil (5-FU) than control cells. The comet assay and annexin V analysis showed decreased DNA damage and cell death in IFIT2-knockdown cells compared to control cells treated with 5-FU. Cell cycle progression was also perturbed by 5-FU treatment, with the accumulation of IFIT2-depleted cells in S phase in a time-dependent manner. We further observed the overexpression of thymidylate synthase (TS) and thymidine kinase (TK) in IFIT2-knockdown cells. Inhibition of TS alone or double inhibition of TS and TK1 using the siRNA technique increased susceptibility to 5-FU in IFIT2-knockdown cells. We further identified that suberanilohydroxamic acid (SAHA) treatment decreased the expression of TS in IFIT2-knockdown cells and demonstrated that pretreatment with SAHA sensitized IFIT2-knockdown cells to 5-FU in vitro and in vivo. In conclusion, IFIT2 knockdown enhances TS expression, which mediates 5-FU resistance, and SAHA pretreatment suppresses TS expression and hence sensitizes cells to 5-FU. SAHA will be an effective strategy for the treatment of OSCC patients with 5-FU resistance.

Emerging Functions of Human IFIT Proteins in Cancer

Interferon-induced protein with tetratricopeptide repeats (IFIT) genes are prominent interferon-stimulated genes (ISGs). The human IFIT gene family consists of four genes named IFIT1, IFIT2, IFIT3, and IFIT5. The expression of IFIT genes is very low in most cell types, whereas their expression is greatly enhanced by interferon treatment, viral infection, and pathogen-associated molecular patterns (PAMPs). The proteins encoded by IFIT genes have multiple tetratricopeptide repeat (TPR) motifs. IFIT proteins do not have any known enzymatic roles. However, they execute a variety of cellular functions by mediating protein-protein interactions and forming multiprotein complexes with cellular and viral proteins through their multiple TPR motifs. The versatile tertiary structure of TPR motifs in IFIT proteins enables them to be involved in distinct biological functions, including host innate immunity, antiviral immune response, virus-induced translation initiation, replication, double-stranded RNA signaling, and PAMP recognition. The current understanding of the IFIT proteins and their role in cellular signaling mechanisms is limited to the antiviral immune response and innate immunity. However, recent studies on IFIT protein functions and their involvement in various molecular signaling mechanisms have implicated them in cancer progression and metastasis. In this article, we focused on critical molecular, biological and oncogenic functions of human IFIT proteins by reviewing their prognostic significance in health and cancer. Research suggests that IFIT proteins could be novel therapeutic targets for cancer therapy.

Bioinformatics Analysis of Potential Key Genes in Trastuzumab-Resistant Gastric Cancer

Background

This study was performed to identify genes related to acquired trastuzumab resistance in gastric cancer (GC) and to analyze their prognostic value.

Methods

The gene expression profile GSE77346 was downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were obtained by using GEO2R. Functional and pathway enrichment was analyzed by using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Search Tool for the Retrieval of Interacting Genes (STRING), Cytoscape, and MCODE were then used to construct the protein-protein interaction (PPI) network and identify hub genes. Finally, the relationship between hub genes and overall survival (OS) was analyzed by using the online Kaplan-Meier plotter tool.

Results

A total of 327 DEGs were screened and were mainly enriched in terms related to pathways in cancer, signaling pathways regulating stem cell pluripotency, HTLV-I infection, and ECM-receptor interactions. A PPI network was constructed, and 18 hub genes (including one upregulated gene and seventeen downregulated genes) were identified based on the degrees and MCODE scores of the PPI network. Finally, the expression of four hub genes (ERBB2, VIM, EGR1, and PSMB8) was found to be related to the prognosis of HER2-positive (HER2+) gastric cancer. However, the prognostic value of the other hub genes was controversial; interestingly, most of these genes were interferon- (IFN-) stimulated genes (ISGs).

Conclusions

Overall, we propose that the four hub genes may be potential targets in trastuzumab-resistant gastric cancer and that ISGs may play a key role in promoting trastuzumab resistance in GC.

Decreased IFIT2 Expression In Human Non-Small-Cell Lung Cancer Tissues Is Associated With Cancer Progression And Poor Survival Of The Patients

Background

IFIT2 (interferon-induced proteins with tetratricopeptide repeats 2), also known as ISG54, is an important interferon-stimulated gene family protein, which has been confirmed to play a crucial role in anti-cancer as well as anti-virus process. In the present study, we aimed to investigate the IFIT2 expression in human non-small-cell cancer (NSCLC) tissues and its clinical implications.

Methods

The immunohistochemistry assay was used to identify the clinical significance and prognostic value of IFIT2 expression in NSCLC tissues. The depletion of IFIT2 was achieved using RNAi approach to assess the role of IFIT2 in the regulation of biological behaviors in human lung cancer cell lines.

Results

Decreased IFIT2 expression was found in human NSCLC tissues (both in lung adenocarcinoma and lung squamous cell carcinoma) in contrast to the adjacent normal tissues (both P<0.0001, respectively). We did not find any significant correlations between the IFIT2 expression and patient’s clinicopathological features. The survival analysis showed that the overall survival (OS) of patients in IFIT2 low expression group was significantly poorer than that in IFIT2 high expression group (in lung adenocarcinoma: P=0.027; and in lung squamous cell carcinoma: P=0.029). The Cox model analysis also indicated that the distant metastasis (P=0.043) could be used as an independent prognostic factor for lung adenocarcinoma patients, and the lymph node metastasis (P=0.045) and IFIT2 low expression (P=0.020) could be used as independent prognostic factors for lung squamous cell carcinoma patients. Moreover, the depletion of IFIT2 in human lung cancer cell lines A549, H1975 and SK-MES-1 significantly increased the cellular abilities, such as viability, migration and invasion.

Conclusion

Decreased IFIT2 was involved in the initiation and the progression of human NSCLC, and its underlying mechanisms still needs further investigation.

Long-Term Exposure to Oroxylin A Inhibits Metastasis by Suppressing CCL2 in Oral Squamous Cell Carcinoma Cells

Oroxylin A (Oro-A), the main bioactive flavonoid extracted from Scutellaria radix, has been reported to inhibit migration in various human cancer cell models. In this study, we further explored the anti-migration effects of Oro-A on oral squamous cell carcinoma (OSCC) cells and investigated the underlying mechanisms. A 24-h (short-term) exposure of OSCC cells to non-cytotoxic concentrations (5⁻20 μM) of Oro-A significantly suppressed cell migration according to a wound-healing assay. Furthermore, a 30-day exposure (long-term) to Oro-A (20 μM), which did not exhibit a cytotoxic effect on OSCC cells, significantly suppressed cell migration more than short-term Oro-A exposure. To uncover the molecular mechanisms underlying the inhibitory effect of long-term Oro-A exposure on OSCC migration, a cDNA microarray and the Ingenuity software were used. Overall, 112 upregulated and 356 downregulated genes were identified in long-term Oro-A-exposed cells compared with untreated OSCC cells. Among them, 75 genes were reported to be associated with cancer cell migration. Consistent with the cDNA microarray results, we found that the expression levels of several cell migration-related genes, such as LCN2, ID-1, MDK, S100A9 and CCL2, were significantly decreased in long-term Oro-A-exposed OSCC cells using a quantitative real-time polymerase chain reaction (Q-PCR) assay. The Western blotting and enzyme-linked immunosorbent assay (ELISA) results also demonstrated that CCL2 expression at the mRNA and protein levels was significantly decreased in long-term Oro-A-exposed OSCC cells compared with untreated OSCC cells. Moreover, the expression levels of downstream CCL2 targets, including p-ERK1/2, NFκB, MMP2, and MMP9, were also decreased in long-term Oro-A-exposed OSCC cells. Further, Oro-A treatment suppressed in vivo metastasis. These results suggest that long-term Oro-A treatment inhibits metastasis via CCL2 signaling in OSCC cells.

IFIT1 and IFIT3 promote oral squamous cell carcinoma metastasis and contribute to the anti-tumor effect of gefitinib via enhancing p-EGFR recycling

IFIT1 and IFIT3 are abundant products of interferon-stimulating genes. While the importance of IFIT1 and IFIT3 in the prognosis of cancer has been reported, the molecular basis of IFIT1 and IFIT3 in cancer progression remains unexplored. In the present study, we investigated the modes of action and the clinical significance of IFIT1 and IFIT3 in oral squamous cell carcinoma (OSCC). Ectopic expression of IFIT1 or IFIT3 induced OSCC cell invasion by promoting the epithelial-mesenchymal transition, whereas IFIT1 or IFIT3 knockdown exhibited opposite effects. Overexpression of IFIT1 or IFIT3 promoted tumor growth, regional and distant metastasis in xenograft and orthotopic nude mice models. Most importantly, IFIT1 or IFIT3 overexpression increased the levels of p-EGFR^Y1068 and p-AKT^S473 in OSCC cells and also enhanced tumor inhibitory effect of gefitinib. By immunoprecipitation and LC-MS/MS analysis, we found that IFIT1 and IFIT3 interacted with ANXA2 that enhanced p-EGFR^Y1068 endosomal recycling. Depletion of ANXA2 using siRNA therefore abolished p-EGFR^Y1068 and p-AKT^S473 expression in IFIT1- or IFIT3-overexpressed cells. Furthermore, a significant positive association of increased IFIT1 and IFIT3 expression with advanced T-stage, lymph node metastasis, perineural invasion, lymphovascular invasion, extranodal extension, and poor overall survival rate was confirmed in OSCC patients. We also found a statistically positive correlation of p-EGFR^Y1068 expression with IFIT1 and IFIT3 in OSCC tumors and poor clinical outcome in patients. Collectively, we demonstrated a novel role of IFIT1 and IFIT3 in driving OSCC progression and metastasis by interacting with ANXA2 and hence enhancing p-EGFR recycling and its downstream signaling.

Integrated miRNA and mRNA transcriptomes of spleen profiles between Yorkshire and Queshan black pigs

Disease causes large economic losses to the pig industry worldwidely, immunity plays an important role in the process of resistance to disease. In the present study, to elucidate the molecular mechanisms underlying different levels of disease resistance, we obtained the miRNA and mRNA expression profiles from the spleens of three groups of sows, including 180-day-old Queshan Black (Q-F), 3-day-old Yorkshire (Y-N) and 180-day-old Yorkshire (Y-F) pigs. The results showed that 85 miRNAs and 5093 genes were differentially expressed in Y-F vs Y-N, and 20 miRNAs and 1283 genes were differentially expressed in Q-F vs Y-F. Gene ontology analysis of these differentially expressed genes revealed their critical roles in response to immune response-related signaling pathways. To investigate the molecular mechanisms underlying immune diversity based on differentially expressed miRNAs and genes, the regulatory network between the node miRNAs and genes were established using Cytoscape. The results showed that the identified candidate miRNAs and genes were associated with immune response, and also indicated their potential roles in disease resistance variance between different pig breeds and stages. From the above, this research detected the key factors that were involved in disease resistance, and provide useful information for disease resistance breeding.

Prognostic Values of EPDR1 Hypermethylation and Its Inhibitory Function on Tumor Invasion in Colorectal Cancer

Aberrant DNA methylation is a potential mechanism underlying the development of colorectal cancer (CRC). Thus, identification of prognostic DNA methylation markers and understanding the related molecular functions may offer a new perspective on CRC pathogenesis. To that end, we explored DNA methylation profile changes in CRC subtypes based on the microsatellite instability (MSI) status through genome-wide DNA methylation profiling analysis. Of 34 altered genes, three hypermethylated (epidermal growth factor, EGF; carbohydrate sulfotransferase 10, CHST10; ependymin related 1, EPDR1) and two hypomethylated (bone marrow stromal antigen 2, BST2; Rac family small GTPase 3, RAC3) candidates were further validated in CRC patients. Based on quantitative methylation-specific polymerase chain reaction (Q-MSP), EGF, CHST10 and EPDR1 showed higher hypermethylated levels in CRC tissues than those in adjacent normal tissues, whereas BST2 showed hypomethylation in CRC tissues relative to adjacent normal tissues. Additionally, among 75 CRC patients, hypermethylation of CHST10 and EPDR1 was significantly correlated with the MSI status and a better prognosis. Moreover, EPDR1 hypermethylation was significantly correlated with node negativity and a lower tumor stage as well as with mutations in B-Raf proto-oncogene serine/threonine kinase (BRAF) and human transforming growth factor beta receptor 2 (TGFβR2). Conversely, a negative correlation between the mRNA expression and methylation levels of EPDR1 in CRC tissues and cell lines was observed, revealing that DNA methylation has a crucial function in modulating EPDR1 expression in CRC cells. EPDR1 knockdown by a transient small interfering RNA significantly suppressed invasion by CRC cells, suggesting that decreased EPDR1 levels may attenuate CRC cell invasion. These results suggest that DNA methylation-mediated EPDR1 epigenetic silencing may play an important role in preventing CRC progression.

Better together: the role of IFIT protein-protein interactions in the antiviral response

The interferon-induced proteins with tetratricopeptide repeats (IFITs) are a family of antiviral proteins conserved throughout all vertebrates. IFIT1 binds tightly to non-self RNA, particularly capped transcripts lacking methylation on the first cap-proximal nucleotide, and inhibits their translation by out-competing the cellular translation initiation apparatus. This exerts immense selection pressure on cytoplasmic RNA viruses to maintain mechanisms that protect their messenger RNA from IFIT1 recognition. However, it is becoming increasingly clear that protein-protein interactions are necessary for optimal IFIT function. Recently, IFIT1, IFIT2 and IFIT3 have been shown to form a functional complex in which IFIT3 serves as a central scaffold to regulate and/or enhance the antiviral functions of the other two components. Moreover, IFITs interact with other cellular proteins to expand their contribution to regulation of the host antiviral response by modulating innate immune signalling and apoptosis. Here, we summarize recent advances in our understanding of the IFIT complex and review how this impacts on the greater role of IFIT proteins in the innate antiviral response.

Pathogenic Effects of IFIT2 and Interferon-β during Fatal Systemic Candida albicans Infection

A balanced immune response to infection is essential to prevent the pathology and tissue damage that can occur from an unregulated or hyperactive host defense. Interferons (IFNs) are critical mediators of the innate defense to infection, and in this study we evaluated the contribution of a specific gene coding for IFIT2 induced by type I IFNs in a murine model of disseminated Candida albicans Invasive candidiasis is a frequent challenge during immunosuppression or surgical medical interventions, and C. albicans is a common culprit that leads to high rates of mortality. When IFIT2 knockout mice were infected systemically with C. albicans, they were found to have improved survival and reduced fungal burden compared to wild-type mice. One of the mechanisms by which IFIT2 increases the pathological effects of invasive C. albicans appears to be suppression of NADPH oxidase activation. Loss of IFIT2 increases production of reactive oxygen species by leukocytes, and we demonstrate that IFIT2 is a binding partner of a critical regulatory subunit of NADPH oxidase, p67phox Since the administration of IFN has been used therapeutically to combat viral infections, cancer, and multiple sclerosis, we evaluated administration of IFN-β to mice prior to C. albicans infection. IFN-β treatment promoted pathology and death from C. albicans infection. We provide evidence that IFIT2 increases the pathological effects of invasive C. albicans and that administration of IFN-β has deleterious effects during infection.IMPORTANCE The attributable mortality associated with systemic C. albicans infections in health care settings is significant, with estimates greater than 40%. This life-threatening disease is common in patients with weakened immune systems, either due to disease or as a result of therapies. Type I interferons (IFN) are cytokines of the innate defense response that are used as immune modulators in the treatment of specific cancers, viral infections, and multiple sclerosis. In this study, we show using a murine model that the loss of a specific IFN-stimulated gene coding for IFIT2 improves survival following systemic C. albicans infection. This result infers a harmful effect of IFN during C. albicans infection and is supported by our finding that administration of IFN-β prior to invasive infection promotes fatal pathology. The findings contribute to our understanding of the innate immune response to C. albicans, and they suggest that IFN therapies present a risk factor for disseminated candidiasis.

Retracted: Risk-Associated Long Noncoding RNA FOXD3-AS1 Inhibits Neuroblastoma Progression by Repressing PARP1-Mediated Activation of CTCF

Neuroblastoma (NB) is the most common extracranial tumor in childhood. Recent studies have implicated the emerging roles of long noncoding RNAs (lncRNAs) in tumorigenesis and aggressiveness. However, the functions and targets of risk-associated lncRNAs in NB progression still remain to be determined. Herein, through mining of public microarray datasets, we identify lncRNA forkhead box D3 antisense RNA 1 (FOXD3-AS1) as an independent prognostic marker for favorable outcome of NB patients. FOXD3-AS1 is downregulated in NB tissues and cell lines, and ectopic expression of FOXD3-AS1 induces neuronal differentiation and decreases the aggressiveness of NB cells in vitro and in vivo. Mechanistically, as a nuclear lncRNA, FOXD3-AS1 interacts with poly(ADP-ribose) polymerase 1 (PARP1) to inhibit the poly(ADP-ribosyl)ation and activation of CCCTC-binding factor (CTCF), resulting in derepressed expression of downstream tumor-suppressive genes. Rescue experiments indicate that FOXD3-AS1 harbors tumor-suppressive properties by inhibiting the oncogenic roles of PARP1 or CTCF and plays crucial roles in all-trans-retinoic-acid-mediated therapeutic effects on NB. Administration of FOXD3-AS1 construct or siRNAs against PARP1 or CTCF reduces the tumor growth and prolongs the survival of nude mice. These findings suggest that as a risk-associated lncRNA, FOXD3-AS1 inhibits the progression of NB through repressing PARP1-mediated CTCF activation.

PLZF inhibits proliferation and metastasis of gallbladder cancer by regulating IFIT2

Gallbladder cancer (GBC) is a malignant cancer with very poor prognosis. Although promyelocytic leukemia zinc-finger protein (PLZF) was reported to be deregulated in numerous cancers and also relevant to clinical prognosis, its role in GBC progression has been little known. In this study, we found PLZF expression was decreased in GBC, correlating to advanced TNM stage, distant metastasis, and shorter overall survival. Moreover, ectopic PLZF expression in GBC cells (NOZ and GBC-SD) significantly reduced the cell proliferation, migration, and invasion. Consistently, overexpression of PLZF in xenograft mice model could suppress tumor growth and liver metastasis. Mechanical investigations verified PLZF could regulate the expression of cell cycle arrest-associated gene p21 and epithelial-mesenchymal transition (EMT)-related genes (E-cadherin and N-cadherin) in GBC cell lines. Importantly, PLZF remarkably increased the mRNA transcription of interferon-induced protein with tetratricopeptide repeat 2 (IFIT2) by increasing STAT1 protein level, a known factor involved in tumor progression. Furthermore, ablation of IFIT2 in PLZF overexpression cells abrogated the tumor-suppressive function of PLZF, at least partially, leading to impaired tumor growth and EMT program. These studies indicated PLZF inhibited the proliferation and metastasis via regulation of IFIT2. In conclusion, our study demonstrated PLZF could be a promising tumor biomarker for GBC, and also be a potential therapeutic target.

Long non-coding RNA00364 represses hepatocellular carcinoma cell proliferation via modulating p-STAT3-IFIT2 signaling axis

The effects of long non-coding RNAs (lncRNAs) on hepatocellular carcinoma (HCC) remain largely unclear. In this study, we identified an interferon (IFN)-γ-induced LncRNA, LncRNA00364, in HCC by microarray. LncRNA00364 displays lower expression in HCC tumor samples compared to paired normal controls. Overexpression of LncRNA00364 inhibits cell proliferation, G1/S cell cycle progression and promotes apoptosis in HCC cell lines. Consistently, LncRNA00364 overexpression leads to decreased HCC tumor formation in vivo. Mechanistically, LncRNA00364 specifically binds with STAT3, resulting in inhibition of STAT3 phosphorylation and therefore leads to upregulation of IFIT2. In a clinical setting, LncRNA00364 shows an independent prognostic indicator for overall survival and cumulative recurrence in HCC patients, and correlates with IFIT2. Therefore, our study provides new insights into a novel therapeutic avenue targeting the LncRNA00364 signaling axis in HCC.

Prostate-derived ETS factor improves prognosis and represses proliferation and invasion in hepatocellular carcinoma

Prostate-derived E-twenty-six (ETS) factor (PDEF), an epithelium-specific ETS transcription factor, regulates carcinogenesis and tumor progression. The prognostic importance and biologic functions in hepatocellular carcinoma (HCC) have not been established. We investigated PDEF expression in 400 HCC patients using quantitative real-time polymerase chain reaction, western blot and immunohistochemistry analysis. PDEF expression was significantly lower in tumors than in peritumoral tissues. Lower PDEF levels were associated with poorer prognosis in patients. PDEF was an independent predictor of overall survival in multivariate analysis. PDEF expression was suppressed in highly metastatic HCC cell lines, and shRNA-mediated down-regulation of PDEF in low-metastatic HCC cell lines (with high PDEF) significantly increased cellular proliferative and invasive capacity in vitro and in vivo. RNA sequencing analysis indicated that PDEF may mediate transcription of several genes involved in apoptosis and the cell cycle. PDEF modulated epithelial-mesenchymal transition by up-regulating E-cadherin expression and down-regulating Slug and Vimentin expression, thereby lowering migration and invasion abilities of HCC cells. In conclusion, PDEF is associated with proliferation and invasiveness of HCC cells. It may serve as an independent predictor of prognosis in patients with HCC.

Liposomal Spherical Nucleic Acids for Regulating Long Noncoding RNAs in the Nucleus

Emerging evidence indicates that long noncoding RNAs (lncRNAs) are actively involved in a number of developmental and tumorigenic processes. Here, the authors describe the first successful use of spherical nucleic acids as an effective nanoparticle platform for regulating lncRNAs in cells; specifically, for the targeted knockdown of the nuclear-retained metastasis associated lung adenocarcinoma transcript 1 (Malat1), a key oncogenic lncRNA involved in metastasis of several cancers. Utilizing the liposomal spherical nucleic acid (LSNA) constructs, the authors first explored the delivery of antisense oligonucleotides to the nucleus. A dose-dependent inhibition of Malat1 upon LSNA treatment as well as the consequent up-regulation of tumor suppressor messenger RNA associated with Malat1 knockdown are shown. These findings reveal the biologic and therapeutic potential of a LSNA-based antisense strategy in targeting disease-associated, nuclear-retained lncRNAs.

Inhibition of Proteasome Activity Induces Aggregation of IFIT2 in the Centrosome and Enhances IFIT2-Induced Cell Apoptosis

IFN-induced protein with tetratricopeptide repeats 2 (IFIT2), one of the most highly responsive interferon-stimulated genes, inhibits the proliferation and migration of cancer cells and regulates viral replication. IFIT2 has been demonstrated to be a cytoskeleton-associated protein that becomes enriched in the mitotic spindle of cells. However, the molecular mechanisms by which IFIT2 executes biological functions are largely unclear. The findings of this study showed that inhibiting the activation of proteasome led to the enrichment of IFIT2 and induced the aggregation of IFIT2 protein in the centrosome. Microtubule inhibitor colchicine and dynein inhibitor ciliobrevin inhibited the proteasome inhibitor-induced aggregation of IFIT2 protein in the centrosome. Intriguingly, IFIT2 and proteasome inhibitor worked together to induce the apoptosis of cancer cells. The results of the present study revealed that the inhibition of proteasome activity blocked the degradation of IFIT2 and promoted the aggregation of IFIT2 in the centrosome, which in turn induced cell apoptosis. In short, IFIT2 may be a potential target for cancer therapeutics.

Curcumin induces apoptosis in human leukemic cell lines through an IFIT2-dependent pathway

Curcumin, the primary bioactive component isolated from turmeric, has been shown to possess variety of biologic functions including anti-cancer activity. However, molecular mechanisms in different cancer cells are various. In the present study, we demonstrated that curcumin induced G2/M cell cycle arrest and apoptosis by increasing the expression levels of cleaved caspase-3, cleaved PARP and decreasing the expression of BCL^-2 in U937 human leukemic cells but not in K562 cells. We found some interferon induced genes, especially interferon-induced protein with tetratricopeptide repeats 2 (IFIT2), were significantly upregulated when treated with curcumin in U937 cells by gene expression chip array, and further confirmed that the expression of IFIT2 was obviously higher in U937 than that in K562 cells by Western blot assay. In addition, inhibiting the expression of IFIT2 by shRNA in U937 rescued curcumin-induced apoptosis and exogenous overexpression of IFIT2 by lentiviral transduction or treating with IFNγ in K562 cells enhanced anti-cancer activity of curcumin. These results indicated for the first time that curcumin induced leukemic cell apoptosis via an IFIT2-dependent signaling pathways. The present study identified a novel mechanism underlying the antitumor effects of curcumin, and may provide a theoretical basis for curcumin combined with interferon in the cancer therapeutics.

Long non-coding RNA LINC00161 sensitises osteosarcoma cells to cisplatin-induced apoptosis by regulating the miR-645-IFIT2 axis

Chemotherapeutic insensitivity remains a major obstacle to osteosarcoma treatment. Recently, increasing evidence has suggested that long non-coding RNAs (lncRNAs) play an essential role in tumourigenesis. However, the potential biological roles and regulatory mechanisms of novel lncRNAs in response to cisplatin treatment are poorly understood. Here, we found that lncRNA LINC00161 was induced by cisplatin in osteosarcoma cells. Elevated LINC00161 increased cisplatin-induced apoptosis and reversed the cisplatin-resistant phenotype of osteosarcoma cells by upregulating IFIT2. Further mechanistic studies revealed that LINC00161 could sponge endogenous miR-645 and inhibit its activity leading to IFIT2 increase. In addition, we identified that LINC00161 enhanced cisplatin-induced apoptosis through regulation of the miR-645-IFIT2 pathway. Thus, these findings demonstrate that LINC00161 is an essential regulator in cisplatin-induced apoptosis, and the LINC00161-miR-645-IFIT2 signalling axis plays an important role in reducing osteosarcoma chemoresistance.

Quantitative proteomic analysis for novel biomarkers of buccal squamous cell carcinoma arising in background of oral submucous fibrosis

Background

In South and Southeast Asian, the majority of buccal squamous cell carcinoma (BSCC) can arise from oral submucous fibrosis (OSF). BSCCs develop in OSF that are often not completely resected, causing local relapse. The aim of our study was to find candidate protein biomarkers to detect OSF and predict prognosis in BSCCs by quantitative proteomics approaches.

Methods

We compared normal oral mucosa (NBM) and paired biopsies of BSCC and OSF by quantitative proteomics using isobaric tags for relative and absolute quantification (iTRAQ) to discover proteins with differential expression. Gene Ontology and KEGG networks were analyzed. The prognostic value of biomarkers was evaluated in 94 BSCCs accompanied with OSF. Significant associations were assessed by Kaplan-Meier survival and Cox-proportional hazards analysis.

Results

In total 30 proteins were identified with significantly different expression (false discovery rate < 0.05) among three tissues. Two consistently upregulated proteins, ANXA4 and FLNA, were validated. The disease-free survival was negatively associated with the expression of ANXA4 (hazard ratio, 3.4; P = 0.000), FLNA (hazard ratio, 2.1; P = 0.000) and their combination (hazard ratio, 8.8; P = 0.002) in BSCCs.

Conclusion

The present study indicates that iTRAQ quantitative proteomics analysis for tissues of BSCC and OSF is a reliable strategy. A significantly up-regulated ANXA4 and FLNA could be not only candidate biomarkers for BSCC prognosis but also potential targets for its therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2650-1) contains supplementary material, which is available to authorized users.

Blocking TNF-α inhibits angiogenesis and growth of IFIT2-depleted metastatic oral squamous cell carcinoma cells

Our previous study demonstrated that the depletion of interferon-induced protein with tetratricopeptide repeats 2 (IFIT2) promoted metastasis and was associated with a poor prognosis in patients with oral squamous cell carcinoma (OSCC). Our current study explores the major downstream signaling involved in IFIT2 depletion-induced OSCC metastasis. To this end, we used two cell lines (designated sh-control-xeno and sh-IFIT2-xeno) derived from human OSCC xenografts expressing sh-control and sh-IFIT2, respectively, and one metastatic OSCC subline (sh-IFIT2-meta) from an IFIT2-depleted metastatic tumor. We found that the sh-IFIT2-meta cells proliferated more slowly than the sh-control-xeno cells but exhibited higher migration and chemoresistance. Using microarray technology and Ingenuity Pathway Analysis, we found that TNF-α was one of the major downstream targets in IFIT2-depleted OSCC cells. Quantitative real-time PCR, western blotting, and ELISA results confirmed that TNF-α was upregulated in the sh-IFIT2-meta cells. Blocking TNF-α abolished the angiogenic activity induced by the sh-IFIT2-meta cells. Furthermore, the human-specific TNF-α antibody golimumab significantly inhibited in vivo angiogenesis, tumor growth and metastasis of sh-IFIT2-meta cells. These results demonstrate that IFIT2 depletion results in TNF-α upregulation, leading to angiogenesis and metastasis of OSCC cells.

Proteomic analysis of HEK293 cells expressing non small cell lung carcinoma associated epidermal growth factor receptor variants reveals induction of heat shock response

In view of the fact that certain non small cell lung carcinoma associated epidermal growth factor receptor mutations keep the receptor constitutively active, the downstream effectors of altered activity of mutant receptors are largely unknown. By 2D gel electrophoresis and MALDI-TOF/MS analysis, we showed that increased activity of EGFR mutants, L858R, L861Q and A871G induce heat shock proteins such as Hsp70, Hsp60, Hsp90B1, Hsp5a, Hsp71 and few transcriptional factors. Of which, Hsp70 was observed to be regulated more selectively to L861Q mutant. Our results suggest the possible role of heat shock proteins in lung tumor progression considering EGFR mutations.

Migration and invasion of oral squamous carcinoma cells is promoted by WNT5A, a regulator of cancer progression

BACKGROUND

Oral squamous cell carcinoma (OSCC) constitutes 90% of all cancers in the oral cavity, and the prognosis for patients diagnosed with OSCC is still poor. The identification of novel therapeutic targets and prognostic markers for OSCC is therefore essential. Previous studies of OSCC revealed an increased expression of WNT5A in the tumor tissue. However, no functional studies of WNT5A-induced effects in OSCC have been performed.

METHODS

Two different OSCC cell lines were used for analysis of WNT5A expression by Western blot, whereas WNT5A-induced responses were analyzed by measuring calcium (Ca²⁺) signaling, PKC activation, migration and invasion.

RESULTS

Despite the lack of WNT5A expression, both cell lines responded to recombinant WNT5A (rWNT5A) with activation of the non-canonical WNT/Ca²⁺ /PKC pathway. This effect was ascertained to be mediated by WNT5A by use of the WNT5A antagonist, Box5. To investigate how WNT5A affects tumor progression, rWNT5A-induced alterations in BrdU absorbance (reflecting the number of tumor cells) were analyzed. rWNT5A had no effect on BrdU absorbance but instead promoted tumor cell migration and invasion. These results were confirmed by the use of the WNT5A-mimicking peptide Foxy5, while the rWNT5A-induced migration was blocked by secreted Frizzled-related protein 1 (SFRP1), protein kinase C inhibitors or the intracellular Ca²⁺ chelator, MAPT.

CONCLUSIONS

These novel data clearly show that WNT5A activates the non-canonical WNT/Ca²⁺ /PKC pathway and increases migration and invasion of OSCC cells. This may indicate how an increased WNT5A expression in the tumor tissue is likely to promote progression of OSCC.

SILAC-based proteomic profiling of the human MDA-MB-231 metastatic breast cancer cell line in response to the two antitumoral lactoferrin isoforms: the secreted lactoferrin and the intracellular delta-lactoferrin

Background

Lactoferrins exhibit antitumoral activities either as a secretory lactoferrin or an intracellular delta-lactoferrin isoform. These activities involve processes such as regulation of the cell cycle and apoptosis. While lactoferrin has been shown to exert its function by activating different transduction pathways, delta-lactoferrin has been proven to act as a transcription factor. Like many tumor suppressors, these two proteins are under-expressed in several types of cancer, particularly in breast cancer.

Methodology/Principal Findings

In order to compare the differential effects of the re-introduction of lactoferrin isoforms in breast cancer cells we chose the cancerous mammary gland MDA-MB-231 cell line as a model. We produced a cell line stably expressing delta-lactoferrin. We also treated these cells with fresh purified human breast lactoferrin. We performed two quantitative proteomic studies in parallel using SILAC coupled to mass spectrometry in order to compare the effects of different doses of the two lactoferrin isoforms. The proteome of untreated, delta-lactoferrin expressing and human lactoferrin treated MDA-MB-231 cells were compared. Overall, around 5300 proteins were identified and quantified using the in-house developed MFPaQ software. Among these, expression was increased by 1.5-fold or more for around 300 proteins in delta-lactoferrin expressing cells and 190 proteins in lactoferrin treated cells. At the same time, about 200 and 40 proteins were found to be downregulated (0-0.7-fold) in response to delta-lactoferrin and lactoferrin, respectively.

Conclusions/Significance

Re-introduction of delta-lactoferrin and lactoferrin expression in MDA-MB-231 mainly leads to modifications of protein profiles involved in processes such as proliferation, apoptosis, oxidative stress, the ubiquitin pathway, translation and mRNA quality control. Moreover, this study identified new target genes of delta-lactoferrin transcriptional activity such as SelH, GTF2F2 and UBE2E1.

Protein Kinase C (PKC) Isozymes and Cancer

Protein kinase C (PKC) is a family of phospholipid-dependent serine/threonine kinases, which can be further classified into three PKC isozymes subfamilies: conventional or classic, novel or nonclassic, and atypical. PKC isozymes are known to be involved in cell proliferation, survival, invasion, migration, apoptosis, angiogenesis, and drug resistance. Because of their key roles in cell signaling, PKC isozymes also have the potential to be promising therapeutic targets for several diseases, such as cardiovascular diseases, immune and inflammatory diseases, neurological diseases, metabolic disorders, and multiple types of cancer. This review primarily focuses on the activation, mechanism, and function of PKC isozymes during cancer development and progression.

Interferons and their stimulated genes in the tumor microenvironment

Constitutive expression of interferons (IFNs) and activation of their signaling pathways have pivotal roles in host responses to malignant cells in the tumor microenvironment. IFNs are induced by the innate immune system and in tumors through stimulation of Toll-like receptors (TLRs) and through other signaling pathways in response to specific cytokines. Although in the oncologic context IFNs have been thought of more as exogenous pharmaceuticals, the autocrine and paracrine actions of endogenous IFNs probably have even more critical effects on neoplastic disease outcomes. Through high-affinity cell surface receptors, IFNs modulate transcriptional signaling, leading to regulation of more than 2,000 genes with varying patterns of temporal expression. Induction of the gene products by both unphosphorylated and phosphorylated STAT1 after ligand binding results in alterations in tumor cell survival, inhibition of angiogenesis, and augmentation of actions of T, natural killer (NK), and dendritic cells. The interferon-stimulated gene (ISG) signature can be a favorable biomarker of immune response but, in a seemingly paradoxical finding, a specific subset of the full ISG signature indicates an unfavorable response to DNA-damaging interventions such as radiation. IFNs in the tumor microenvironment thus can alter the emergence, progression, and regression of malignancies.

Regulation of polarized morphogenesis by protein kinase C iota in oncogenic epithelial spheroids

Protein kinase C iota (PKCι), a serine/threonine kinase required for cell polarity, proliferation and migration, is commonly up- or downregulated in cancer. PKCι is a human oncogene but whether this is related to its role in cell polarity and what repertoire of oncogenes acts in concert with PKCι is not known. We developed a panel of candidate oncogene expressing Madin-Darby canine kidney (MDCK) cells and demonstrated that H-Ras, ErbB2 and phosphatidylinositol 3-kinase transformation led to non-polar spheroid morphogenesis (dysplasia), whereas MDCK spheroids expressing c-Raf or v-Src were largely polarized. We show that small interfering RNA (siRNA)-targeting PKCι decreased the size of all spheroids tested and partially reversed the aberrant polarity phenotype in H-Ras and ErbB2 spheroids only. This indicates distinct requirements for PKCι and moreover that different thresholds of PKCι activity are required for these phenotypes. By manipulating PKCι function using mutant constructs, siRNA depletion or chemical inhibition, we have demonstrated that PKCι is required for polarization of parental MDCK epithelial cysts in a 3D matrix and that there is a threshold of PKCι activity above and below which, disorganized epithelial morphogenesis results. Furthermore, treatment with a novel PKCι inhibitor, CRT0066854, was able to restore polarized morphogenesis in the dysplastic H-Ras spheroids. These results show that tightly regulated PKCι is required for normal-polarized morphogenesis in mammalian cells and that H-Ras and ErbB2 cooperate with PKCι for loss of polarization and dysplasia. The identification of a PKCι inhibitor that can restore polarized morphogenesis has implications for the treatment of Ras and ErbB2 driven malignancies.

A death-promoting role for ISG54/IFIT2

The cellular responses to infection are many, and include programmed cell death to inhibit microbial dissemination and the production and secretion of interferons (IFNs), which confer resistance to uninfected cells. In addition to the antimicrobial effects of IFNs, these cytokines have been used clinically for the treatment of various neoplasias to inhibit proliferation and stimulate apoptosis. However, the precise mechanisms of action of IFNs remain to be completely understood. One of the primary response genes induced after an infection or treatment with type I or III IFN is known as IFN-stimulated gene 54 (ISG54) or IFN-induced gene with tetratricopeptide repeats 2 (IFIT2). ISG54/IFIT2 is a member of a family of IFN-induced genes related in the sequence and structure. Expression of this protein has been found to promote cellular apoptosis by a mitochondrial pathway dependent on the action of Bcl2 proteins. ISG54/IFIT2 does not function as a monomer, and it forms complexes with itself and with the related ISG56/IFIT1 and ISG60/IFIT3 proteins to elicit complex cellular responses. The apoptotic response to ISG54/IFIT2 may contribute to other functions that have been reported, including translational regulation, inhibition of tumor colonization, and protection against a lethal viral infection.