BATF2 Deficiency Promotes Progression in Human Colorectal Cancer via Activation of HGF/MET Signaling: A Potential Rationale for Combining MET Inhibitors with IFNs

Role of the basic leucine zipper transcription factor BATF2 in modulating immune responses and inflammation in health and disease

BATF2 is a transcription factor known to exhibit tumor-suppressive activity in cancer cells. Within recent years, however, BATF2 has also emerged as an important transcriptional regulator of the immune system. Through its immunomodulatory function, BATF2 has been implicated in a variety of (patho)physiological processes, including host defense against infection, antitumor immunity, and maintenance of tissue inflammatory homeostasis. Below, we discuss recent literature that has provided insight into the role of BATF2 as a transcriptional regulator of immune responses in health and disease, including the cell types that express BATF2, the different diseases in which the immunomodulatory effects of BATF2 have been shown to play a role, and the molecular mechanisms through which BATF2 is thought to exert those effects. In doing so, we highlight that the immunological effects of BATF2 are highly context dependent, and we point out the overlap between the mechanisms of action of BATF2 in infectious and noninfectious diseases. We also discuss areas of interest for future research, the clinical relevance of better understanding BATF2 function, and potential strategies for therapeutic modulation of BATF2.

miR-939-3p induces sarcoma proliferation and poor prognosis via suppressing BATF2

Background

Sarcoma is a rare and aggressive malignancy with poor prognosis, in which oncogene activation and tumor suppressor inactivation are involved. Accumulated studies suggested basic leucine zipper transcription factor ATF-like 2 (BATF2) as a candidate tumor suppressor, but its specific role and mechanism in sarcoma remain unclear.

Methods

The expression levels of BATF2 and miR-939-3p were evaluated by using human sarcoma samples, cell lines and xenograft mouse models. Bioinformatics analysis, qPCR, Western blot, cell proliferation assay, overexpression plasmid construction, point mutation and dual luciferase reporter assay were utilized to investigate the role and mechanism of miR-939-3p in sarcoma.

Results

In this study, we demonstrated that the expression of BATF2 was downregulated in human sarcoma tissues and cell lines. The downregulation of BATF2 was negatively associated with the prognosis of sarcoma patients. Subsequent bioinformatic prediction and experimental validations showed that BATF2 expression was reduced by microRNA (miR)-939-3p mimic and increased by miR-939-3p inhibitor. Additionally, miR-939-3p was upregulated in sarcoma tissues and cells, correlating with a poor prognosis of sarcoma patients. Moreover, miR-939-3p overexpression suppressed sarcoma cell proliferation, which was significantly attenuated by the restoration of BATF2, while siRNA-mediated knockdown of BATF2 aggravated the miR-939-3p-induced promotion of sarcoma cell proliferation. Further computational algorithms and dual-luciferase reporter assays demonstrated that miR-939-3p repressed BATF2 expression via directly binding to its 3' untranslated region (3' UTR).

Conclusion

Collectively, these findings identified miR-939-3p as a novel regulator of BATF2, as well as a prognostic biomarker in sarcoma, and revealed that suppressing miR-939-3p or inducing BATF2 expression may serve as a promising therapeutic strategy against sarcoma.

The role of BATF2 deficiency in immune microenvironment rearrangement in cervical cancer - New biomarker benefiting from combination of radiotherapy and immunotherapy

Despite the significant progress in immunotherapy for certain cancers, including cervical cancer, most patients remain unresponsive or derive limited benefits from combined radiotherapy and chemotherapy. The factors underlying treatment resistance are unknown and there are few reliable predictive biomarkers. BATF2 is a member of the basic leucine zipper transcription factor family and is involved in immune response and immune cell development. However, the role of BATF2 in the immune microenvironment of patients with cervical cancer after radiotherapy remains unclear. In this study, immunohistochemistry and multicolour immunofluorescence analyses of patient tumor samples were used to assess BATF2 expression. We found that cervical cancer patients with high BATF2 expression had higher infiltration levels of CD4+ T cells, CD8+ T cells, and macrophages within the tumor than those with low expression levels. Furthermore, BATF2 expression was positively correlated with the prognosis of patients after concurrent chemoradiotherapy. A wild-type mouse model with BATF2-knockdown U14 cell-derived subcutaneous tumors and a Batf2-/- mouse model with wild-type U14 cell-derived subcutaneous tumors were used to assess CD8+ T cell infiltration and function. As expected, the knockdown of BATF2 in the U14 cell line substantially promoted tumor growth, which was mediated by a reduction in CD8+ T cell infiltration and antitumor function in vivo. Additionally, the Batf2-/- mouse model demonstrated that host BATF2 is also involved in controlling tumor growth. Furthermore, the combination of radiotherapy and anti-PD-1 therapy showed synergistic antitumour effects. These findings collectively suggest that BATF2 may serve as a potent positive regulator of the tumor immune microenvironment of cervical cancer after radiotherapy, and has the potential to be a prognostic biomarker to guide the application of a combination of radiotherapy and immunotherapy.

BATF2 inhibits PD-L1 expression and regulates CD8+ T-cell infiltration in non-small cell lung cancer

Immune checkpoint blockades have made huge breakthrough among some cancer types including lung cancer. However, only a small proportion of patients will benefit from immune checkpoint blockades; other patients have no or minor response to immunotherapy. The underlying mechanisms and efficient biomarkers to predict immunotherapy resistances remain unclear and lacking. In this study, BATF2 knockout mice, human xenograft mice, were used for in vivo studies. Relevant RNA and protein levels were analyzed by RT-quantitative PCR and Western blotting. As a result, we found that the expression of BATF2 is negatively correlated with expression of programmed death-ligand 1 in the plasma of patients. Mechanically, we showed that BATF2 inhibits programmed death-ligand 1 expression in cancer cells by inhibiting the PI3K-AKT pathway where ZEB2 plays an important role in this process. Based on bioinformatics analysis, we found that the function of BATF2 in promoting antitumor immune response in patients with non-small cell lung cancer, which is mediated by BATF2, enhances CD8+ T-cell infiltration as well as activation. The expression of BATF2 from circulating tumor cells and tissues can be serve as an efficient biomarker to predict diagnosis, prognosis, and immunotherapy efficacy.

m6A modification-mediated BATF2 suppresses metastasis and angiogenesis of tongue squamous cell carcinoma through inhibiting VEGFA

The aim is to explore the underlying mechanism of basic leucine zipper ATF-like transcription factor 2 (BATF2) in tongue squamous cell carcinoma (TSCC). The expression of BATF2 in TSCC tissues and corresponding adjacent normal TSCC tissues, human TSCC cell lines (SCC-15 and CAL-27) and human normal tongue epithelial cells NTEC was detected. Then, SCC-15 cells with stable BATF2 knockdown and CAL-27 cells with BATF2 overexpression were established to investigate the functional effect of BATF2 on TSCC. Thereafter, the effect of BATF2 on TSCC angiogenesis and BATF2 m6A methylation was also examined. BATF2 was significantly downregulated in TSCC tissues and cell lines, and BATF2 overexpression could suppress growth, metastasis and angiogenesis of TSCC. Mechanistically, vascular endothelial growth factor A (VEGFA) was identified as a downstream gene of BATF2, and it was confirmed that BATF2 suppressed growth, metastasis and angiogenesis of TSCC via inhibiting VEGFA. In addition, the N6-methyladenosine (m6A) modification of BATF2 mRNA mediated by METTL14 suppressed its expression in TSCC. METTL14/BATF2 axis could serve as a novel promising therapeutic candidate against angiogenesis for TSCC.

Bone marrow mesenchymal stem cells-derived exosomes suppress miRNA-5189-3p to increase fibroblast-like synoviocyte apoptosis via the BATF2/JAK2/STAT3 signaling pathway

Ankylosing spondylitis (AS) is characterized by inflammation of the sacroiliac joint and the attachment point of the spine. Herein, we aimed to investigate the effect of bone marrow mesenchymal stem cells (BMSCs)-derived exosomes on apoptosis of fibroblast-like synoviocytes (FLSs) and explored its molecular mechanism. Exosomes were isolated from BMSCs and verified by transmission electron microscope and nanoparticle tracking analysis. FLSs were isolated and co-incubated with BMSC exosomes. Cell apoptosis was assessed using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling analysis and flow cytometry. The results showed that BMSC exosomes increased apoptosis of FLSs. MiR-5189-3p was downregulated, while basic leucine zipper transcription factor ATF-like 2 (BATF2) was upregulated in FLSs by treatment of BMSC exosomes. As a direct target of miR-5189-3p, BATF2 inactivates the JAK2/STAT3 pathway. MiR-5189-3p suppressed apoptosis of FLSs and BATF2 exerted an opposite effect. In conclusion, BMSCs-derived exosomes suppress miR-5189-3p to facilitate the apoptosis of FLSs via the BATF2/JAK2/STAT3 signaling pathway, which facilitates the understanding of the therapeutic effect of BMSCs on AS and the underlying molecular mechanism.

In PD-1+ human colon cancer cells NIVOLUMAB promotes survival and could protect tumor cells from conventional therapies

BACKGROUND

Colorectal cancer (CRC) is one of the most prevalent and deadly tumors worldwide. The majority of CRC is resistant to anti-programmed cell death-1 (PD-1)-based cancer immunotherapy, with approximately 15% with high-microsatellite instability, high tumor mutation burden, and intratumoral lymphocytic infiltration. Programmed death-ligand 1 (PD-L1)/PD-1 signaling was described in solid tumor cells. In melanoma, liver, and thyroid cancer cells, intrinsic PD-1 signaling activates oncogenic functions, while in lung cancer cells, it has a tumor suppressor effect. Our work aimed to evaluate the effects of the anti-PD-1 nivolumab (NIVO) on CRC cells.

METHODS

In vitro NIVO-treated human colon cancer cells (HT29, HCT116, and LoVo) were evaluated for cell growth, chemo/radiotherapeutic sensitivity, apoptosis, and spheroid growth. Total RNA-seq was assessed in 6-24 hours NIVO-treated human colon cancer cells HT29 and HCT116 as compared with NIVO-treated PES43 human melanoma cells. In vivo mice carrying HT29 xenograft were intraperitoneally treated with NIVO, OXA (oxaliplatin), and NIVO+OXA, and the tumors were characterized for growth, apoptosis, and pERK1/2/pP38. Forty-eight human primary colon cancers were evaluated for PD-1 expression through immunohistochemistry.

RESULTS

In PD-1+ human colon cancer cells, intrinsic PD-1 signaling significantly decreased proliferation and promoted apoptosis. On the contrary, NIVO promoted proliferation, reduced apoptosis, and protected PD-1+ cells from chemo/radiotherapy. Transcriptional profile of NIVO-treated HT29 and HCT116 human colon cancer cells revealed downregulation of BATF2, DRAM1, FXYD3, IFIT3, MT-TN, and TNFRSF11A, and upregulation of CLK1, DCAF13, DNAJC2, MTHFD1L, PRPF3, PSMD7, and SCFD1; the opposite regulation was described in NIVO-treated human melanoma PES43 cells. Differentially expressed genes (DEGs) were significantly enriched for interferon pathway, innate immune, cytokine-mediated signaling pathways. In vivo, NIVO promoted HT29 tumor growth, thus reducing OXA efficacy as revealed through significant Ki-67 increase, pERK1/2 and pP38 increase, and apoptotic cell reduction. Eleven out of 48 primary human colon cancer biopsies expressed PD-1 (22.9%). PD-1 expression is significantly associated with lower pT stage.

CONCLUSIONS

In PD-1+ human colon cancer cells, NIVO activates tumor survival pathways and could protect tumor cells from conventional therapies.

Novel patient-derived models of DSRCT enable validation of ERBB signaling as a potential therapeutic vulnerability

Desmoplastic small round cell tumor (DSRCT) is characterized by the t(11;22)(p13;q12) translocation, which fuses the transcriptional regulatory domain of EWSR1 with the DNA-binding domain of WT1, resulting in the oncogenic EWSR1-WT1 fusion protein. The paucity of DSRCT disease models has hampered preclinical therapeutic studies on this aggressive cancer. Here, we developed preclinical disease models and mined DSRCT expression profiles to identify genetic vulnerabilities that could be leveraged for new therapies. We describe four DSRCT cell lines and one patient-derived xenograft model. Transcriptomic, proteomic and biochemical profiling showed evidence of activation of the ERBB pathway. Ectopic expression of EWSR1-WT1 resulted in upregulation of ERRB family ligands. Treatment of DSRCT cell lines with ERBB ligands resulted in activation of EGFR, ERBB2, ERK1/2 and AKT, and stimulation of cell growth. Antagonizing EGFR function with shRNAs, small-molecule inhibitors (afatinib, neratinib) or an anti-EGFR antibody (cetuximab) inhibited proliferation of DSRCT cells. Finally, treatment of mice bearing DSRCT xenografts with a combination of cetuximab and afatinib significantly reduced tumor growth. These data provide a rationale for evaluating EGFR antagonists in patients with DSRCT.

This article has an associated First Person interview with the joint first authors of the paper.

Summary: Novel models of desmoplastic small round cell tumor (DSRCT) reveal a role for the ERBB pathway in regulating growth of this sarcoma and provide a rationale for evaluating EGFR antagonists in patients with DSRCT.

Identification of prognostic immune genes in laryngeal cancer

Objective

In this study, we aimed to identify prognostic immune-related genes and establish a prognostic model for laryngeal cancer based on these genes.

Methods

Transcriptome profiles and clinical data of patients with laryngeal cancer were downloaded from The Cancer Genome Atlas database. Integrated bioinformatics analyses were performed to identify genes associated with prognosis.

Results

Thirty prognostic immune-related genes for laryngeal cancer were identified. We constructed a regulatory network of prognosis comprising transcription factors and immune-related genes. Multivariate Cox regression analyses identified 15 immune-related genes in the network that were used to establish the prognostic model. The model exhibited excellent prognostic prediction ability with a high area under the curve value (0.916). The calculated risk score based on expression of the 15 immune-related genes was shown to be an independent prognostic factor for laryngeal cancer.

Conclusion

We identified prognostic immune-related genes and established a prognostic model for laryngeal cancer, which might help identify novel predictive biomarkers and therapeutic targets of laryngeal cancer.

The Anti-HER3 mAb Seribantumab Effectively Inhibits Growth of Patient-Derived and Isogenic Cell Line and Xenograft Models with Oncogenic NRG1 Fusions

PURPOSE

Oncogenic fusions involving the neuregulin 1 (NRG1) gene are found in approximately 0.2% of cancers of diverse histologies. The resulting chimeric NRG1 proteins bind predominantly to HER3, leading to HER3-HER2 dimerization and activation of downstream growth and survival pathways. HER3 is, therefore, a rational target for therapy in NRG1 fusion-driven cancers.

EXPERIMENTAL DESIGN

We developed novel patient-derived and isogenic models of NRG1-rearranged cancers and examined the effect of the anti-HER3 antibody, seribantumab, on growth and activation of signaling networks in vitro and in vivo.

RESULTS

Seribantumab inhibited NRG1-stimulated growth of MCF-7 cells and growth of patient-derived breast (MDA-MB-175-VII, DOC4-NRG1 fusion) and lung (LUAD-0061AS3, SLC3A2-NRG1 fusion) cancer cells harboring NRG1 fusions or NRG1 amplification (HCC-95). In addition, seribantumab inhibited growth of isogenic HBEC cells expressing a CD74-NRG1 fusion (HBECp53-CD74-NRG1) and induced apoptosis in MDA-MB-175-VII and LUAD-0061AS3 cells. Induction of proapoptotic proteins and reduced expression of the cell-cycle regulator, cyclin D1, were observed in seribantumab-treated cells. Treatment of MDA-MB-175-VII, LUAD-0061AS3, and HBECp53-CD74-NRG1 cells with seribantumab reduced phosphorylation of EGFR, HER2, HER3, HER4, and known downstream signaling molecules, such as AKT and ERK1/2. Significantly, administration of seribantumab to mice bearing LUAD-0061AS3 patient-derived xenograft (PDX) and OV-10-0050 (ovarian cancer with CLU-NRG1 fusion) PDX tumors induced regression of tumors by 50%-100%. Afatinib was much less effective at blocking tumor growth.

CONCLUSIONS

Seribantumab treatment blocked activation of the four ERBB family members and of downstream signaling, leading to inhibition of NRG1 fusion-dependent tumorigenesis in vitro and in vivo in breast, lung, and ovarian patient-derived cancer models.

Circ_0005927 Inhibits the Progression of Colorectal Cancer by Regulating miR-942-5p/BATF2 Axis

Background

Colorectal cancer (CRC) is one of the most common aggressive neoplasms worldwide. Circular RNAs (circRNAs) have been involved in the biological process of CRC. This study aimed to explore the effects of circ_0005927 on CRC progression and underneath mechanism.

Materials and Methods

The expression of circ_0005927, microRNA-942-5p (miR-942-5p) and basic leucine zipper ATF-like transcription factor 2 (BATF2) was detected by quantitative real time polymerase chain reaction (qRT-PCR). The protein expression of BATF2 was determined by Western blot. The effects among circ_0005927, miR-942-5p and BATF2 on cell colony-forming ability, apoptosis and migratory and invasive abilities were revealed by cell colony formation, flow apoptosis and transwell assays, respectively. The associated relationship between miR-942-5p and circ_0005927 or BATF2 was predicted by Circinteractome or TargetScan online database, and identified by dual-luciferase reporter or RNA immunoprecipitation (RIP) assay. The impacts of circ_0005927 overexpression on tumor growth in vivo were investigated by in vivo tumor formation assay.

Results

Circ_0005927 expression and the mRNA and protein expression of BATF2 were dramatically downregulated, while miR-942-5p expression was obviously upregulated in CRC tissues or cells compared with control groups. Circ_0005927 overexpression repressed cell colony-forming ability, migration and invasion, whereas induced cell apoptosis in CRC; however, these impacts were hindered by miR-942-5p mimic or BATF2 knockdown. Furthermore, circ_0005927 was a sponge of miR-942-5p, and miR-942-5p bound to BATF2. In addition, circ_0005927 overexpression repressed tumor growth in vivo.

Conclusion

Circ_0005927 suppressed cell colony-forming ability, migration and invasion, and promoted cell apoptosis by sponging miR-942-5p to induce BATF2 in CRC. The possible mechanism provides a theoretical basis for the study of circRNA-directed therapy for CRC.

BATF2 prevents glioblastoma multiforme progression by inhibiting recruitment of myeloid-derived suppressor cells

The basic leucine zipper ATF-like transcription factor 2 (BATF2) has been implicated in inflammatory responses and anti-tumour effects. Little, however, is known regarding its extracellular role in maintaining a non-supportive cancer microenvironment. Here, we show that BATF2 inhibits glioma growth and myeloid-derived suppressor cells (MDSCs) recruitment. Interestingly, extracellular vesicles (EVs) from BATF2-overexpressing glioma cell lines (BATF2-EVs) inhibited MDSCs chemotaxis in vitro. Moreover, BATF2 inhibited intracellular SDF-1α and contributes to decreased SDF-1α in EVs. In addition, BATF2 downregulation-induced MDSCs recruitment were reversed by blocking SDF-1α/CXCR4 signalling upon AMD3100 treatment. Specifically, detection of EVs in 24 pairs of gliomas and healthy donors at different stages revealed that the abundance of BATF2-positive EVs in plasma (BATF2⁺ plEVs) can distinguish stage III-IV glioma from stage I-II glioma and healthy donors. Taken together, our study identified novel regulatory functions of BATF2 in regulating MDSCs recruitment, providing a prognostic value in terms of the number of BATF2⁺ plEVs in glioma stage.

Hepatocyte growth factor/MET and CD44 in colorectal cancer: partners in tumorigenesis and therapy resistance

Intestinal epithelial self-renewal is a tightly controlled process, which is critically dependent on WNT signalling. Aberrant activation of the WNT pathway in intestinal stem cells (ISCs) results in constitutive transcription of target genes, which collectively drive malignant transformation in colorectal cancer (CRC). However, the contribution of individual genes to intestinal homeostasis and tumorigenesis often is incompletely defined. Here, we discuss converging evidence indicating that the receptor tyrosine kinase (RTK) MET and its ligand hepatocyte growth factor (HGF) play a major role in the intestinal damage response, as well as in intestinal tumorigenesis, by controlling the proliferation, survival, motility, and stemness of normal and neoplastic intestinal epithelial cells. These activities of MET are promoted by specific CD44 isoforms expressed by ISCs. The accrued data indicate that MET and the EGFR have overlapping roles in the biology of intestinal epithelium and that metastatic CRCs can exploit this redundancy to escape from EGFR-targeted treatments, co-opting HGF/MET/CD44v signalling. Hence, targeting both pathways may be required for effective treatment of (a subset of) CRCs. The RTK identity of MET, the distinctive 'plasminogen-like' structure and activation mode of its ligand HGF, and the specific collaboration of MET with CD44, provide several unique targeting options, which merit further exploration.

Stomatin-like Protein 2 Promotes Tumor Cell Survival by Activating the JAK2-STAT3-PIM1 Pathway, Suggesting a Novel Therapy in CRC

Despite intensive efforts, a considerable proportion of colorectal cancer (CRC) patients develop local recurrence and distant metastasis. Stomatin-like protein 2 (SLP-2), a member of the highly conserved stomatin superfamily, is upregulated across cancer types. However, the biological and functional roles of SLP-2 remain elusive in CRC. Here, we report that high SLP-2 expression was found in CRC tissues and was linked to tumor progression and tumor cell differentiation. Additionally, high SLP-2 expression correlated with poor overall survival (OS) in CRC patients (p < 0.001). SLP-2 knockout (SLP-2KO), generated by CRISPR/Cas9, reduced cell growth, migration, and invasion; induced apoptosis in CRC cells; and reduced tumor xenograft growth in vivo. A 181-compound library screening showed that SLP-2KO produced resistance to JAK2 inhibitors (NVP-BSK805 and TG-101348) and a PIM1 inhibitor (SGI-1776), revealing that the JAK2-STAT3-PIM1 oncogenic pathway was potentially controlled by SLP-2 in CRC. In vitro and in vivo, TG-101348 combined with SGI-1776 was synergistic in CRC (combination index [CI] < 1). Overall, our findings suggest that SLP-2 controls the JAK2-STAT3-PIM1 oncogenic pathway, offering a rationale for a novel therapeutic strategy with combined SGI-1776 and TG-101348 in CRC. Additionally, SLP-2 may be a prognostic marker and biomarker for sensitivity to JAK2 and PIM1 inhibitors.

SARI suppresses colitis-associated cancer development by maintaining MCP-1-mediated tumour-associated macrophage recruitment

SARI (suppressor of AP‐1, regulated by IFN) impaired tumour growth by promoting apoptosis and inhibiting cell proliferation and tumour angiogenesis in various cancers. However, the role of SARI in regulating tumour‐associated inflammation microenvironment is still elusive. In our study, the colitis‐dependent and ‐independent primary model were established in SARI deficiency mice and immuno‐reconstructive mice to investigate the functional role of SARI in regulating tumour‐associated inflammation microenvironment and primary colon cancer formation. The results have shown that SARI deficiency promotes colitis‐associated cancer (CAC) development only in the presence of colon inflammation. SARI inhibited tumour‐associated macrophages (TAM) infiltration in colon tissues, and SARI deficiency in bone marrow cells has no observed role in the promotion of intestinal tumorigenesis. Mechanism investigations indicated that SARI down‐regulates p‐STAT1 and STAT1 expression in colon cancer cells, following inhibition of MCP‐1/CCR2 axis activation during CAC development. Inverse correlations between SARI expression and macrophage infiltration, MCP‐1 expression and p‐STAT1 expression were also demonstrated in colon malignant tissues. Collectively, our results prove the inhibition role of SARI in colon cancer formation through regulating TAM infiltration.

Suppressor of activator protein-1 regulated by interferon expression in prostate cancer tissues and cells

PURPOSE

The aim of this study was to investigate the role of the suppressor of activator protein-1 regulated by interferon (SARI), in the development and progression of prostate cancer.

METHODS

Sixty-seven prostate cancer tissue specimens and 20 benign prostatic hyperplasia specimens were used to investigate the correlation between SARI expression and clinicopathologic parameters. Immunohistochemistry was used to detect the SARI and E-cadherin protein expression in the prostate cancer and benign prostatic hyperplasia specimens, and their correlation was established. Quantitative PCR (qPCR) was used to determine the SARI mRNA expression in a normal prostate cell line (RWPE-1) and prostate cancer cell lines (LNCaP and PC3). Western blotting was used to detect the SARI protein expression in the RWPE-1, LNCaP, and PC3 cell lines.

RESULTS

SARI protein expression did not correlate with the prostate cancer patients' age or serum Prostate-Specific Antigen value but did show a correlation with the tumor stage of prostate cancer and Gleason score. SARI and E-cadherin expression in the prostate cancer tissue was significantly lower than in the benign prostatic hyperplasia specimens, suggesting a positive correlation between the SARI and E-cadherin expression. SARI mRNA and protein were highly expressed in RWPE-1, the normal prostate cell line, but SARI mRNA and protein expression were reduced in the prostate cancer cell lines, LNCaP and PC3. Significant differences in the expression were found between the prostate cancer cell lines and the normal prostate cell line.

CONCLUSION

In this study, high SARI expression was found to be negatively correlated with the development and progression of prostate cancer.

Calycosin suppresses TGF-β-induced epithelial-to-mesenchymal transition and migration by upregulating BATF2 to target PAI-1 via the Wnt and PI3K/Akt signaling pathways in colorectal cancer cells

OBJECTIVES

To determine whether the upregulation of basic leucine zipper ATF-like transcription factor 2 (BATF2) by calycosin suppresses the growth and epithelial-to-mesenchymal transition (EMT) in human colorectal cancer (CRC) cells.

METHOD

Cells were cultured and treated with different concentrations of calycosin for different periods of time. Protein and mRNA expression was determined by western blotting and quantitative PCR. Cell migration was assessed by Transwell experiments. Co-immunoprecipitation and luciferase assays were used to analyze the association between BATF2 and plasminogen activator inhibitor-1. (PAI-1). Cell apoptosis was determined by flow cytometry; β-catenin cellular localization was visualized by immunofluorescent staining.

RESULTS

Calycosin up-regulated the expression of BATF2 via the signal transducer and activator of transcription 3 (STAT3) pathway, which was antagonized by transforming growth factor beta (TGF-β), calycosin promoted the cell apoptosis and growth inhibition via phosphoinositide 3-kinase (PI3K)/Akt pathway. TGF-β promoted cell growth, which was inhibited by calycosin regulating the expression of proliferating cell nuclear antigen (PCNA) via the phosphoinositide 3-kinase pathway. TGF-β suppressed expression of BAX via the phosphoinositide 3-kinase pathway but induced cell apoptosis .calycosin enhanced the effect of TGF-β on cell apoptosis,In addition, calycosin suppressed TGF-β-induced cell migration by increasing BATF2 to target PAI-1. TGF-β-induced EMT was inhibited by calycosin in human CRC LoVo and HCT116 cell lines via the Wnt signaling pathway.

CONCLUSIONS

The induction of BATF2 by calycosin may be a feasible therapeutic option for CRC. .

IFI44L is a novel tumor suppressor in human hepatocellular carcinoma affecting cancer stemness, metastasis, and drug resistance via regulating met/Src signaling pathway

BACKGROUND

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related death worldwide. The disease recurrent rate is relatively high resulted in poor 5-year survival in advanced HCC. Cancer stem cells (CSCs) have been considered to be one of the main mechanisms for chemoresistance, metastasis, and recurrent disease. Interferon-induced protein 44-like (IFI44L) gene is a type I interferon-stimulated gene (ISG) and belongs to the IFI44 family. Previous reports indicated antiviral activity against HCV in IFI44L, however, its precise role and function in HCC has not been unveiled.

METHODS

To explore the characteristics of hepatic CSCs, we successfully enriched hepatic cancer stem-like cells from three established liver cancer cell lines (Hep3B, HepG2, and PLC lines). Parental Hep3B and HepG2 cells and their sphere cells were treated with doxorubicin for 48 h and cell viability was measured by MTT assay. HCC tissue blocks from 217 patients were sampled for tissue microarray (TMA). Follow-up information and histopathological and clinical data including age, gender, tumor grade, advanced stages, HBV, HCV, tumor number, tumor size, relapse-free survival, and overall survival were obtained from the cancer registry and medical charts. The liver TMA was evaluated for IFI44L expression using immunohistochemical staining and scores.

RESULTS

These hepatic cancer stem-like cells possess important cancer stemness characteristics including sphere-forming abilities, expressing important HCC cancer stem cell markers, and more chemoresistant. Interestingly, we found that overexpression of IFI44L decreased chemoresistance towards doxorubicin and knockdown of IFI44L restored chemoresistance as well as promoted sphere formation. Furthermore, we found that depletion of IFI44L enhanced migration, invasion, and pulmonary metastasis through activating Met/Src signaling pathway. Clinically, the expression level of IFI44L significantly reduced in HCC tumor tissues. Low expression of IFI44L levels also correlated with larger tumor size, disease relapse, advanced stages, and poor clinical survival in HCC patients.

CONCLUSION

Taken together, we first demonstrated that IFI44L is a novel tumor suppressor to affect cancer stemness, metastasis, and drug resistance via regulating Met/Src signaling pathway in HCC and can be serve as an important prognostic marker.

Decrease in invasion of HTR-8/SVneo trophoblastic cells by interferon gamma involves cross-communication of STAT1 and BATF2 that regulates the expression of JUN

Trophoblast invasion is one of the critical steps during embryo implantation. IFNG secreted during pregnancy by uterine NK cells acts as a negative regulator of invasion. IFNG in a dose dependent fashion inhibits invasion of HTR-8/SVneo trophoblastic cells. It phosphorylates STAT1 both at tyr 701 and ser 727 residues. Silencing of STAT1 significantly increases invasion (∼59%) of the cells. Based on NGS data, out of 207 genes, BATF2 expression was significantly increased after IFNG treatment. Silencing of BATF2 significantly increases the invasion of cells with (∼53%) or without (∼44%) treatment with IFNG. Expression of BATF2 and STAT1 is dependent on each other, silencing of one significantly inhibit the expression of other. Interestingly, phosphorylated JUN is also regulated by BATF2 and STAT1. Collectively, these findings showed that decrease in the invasion of HTR-8/SVneo cells after IFNG treatment is controlled by STAT1 and BATF2, which further regulates the expression of JUN.

HDAC5, a potential therapeutic target and prognostic biomarker, promotes proliferation, invasion and migration in human breast cancer

Purpose

Histone deacetylase 5 (HDAC5) is an important protein in neural and cardiac diseases and a potential drug target. However, little is known regarding the specific role of HDAC5 in breast cancer (BC). We aimed to evaluate HDAC5 expression in human breast tumors and to determine the effects of the inhibition of HDAC5 expression in BC cells.

Experimental design

HDAC5 expression was evaluated in BC patients and was correlated with clinical features and with patient prognosis. Functional experiments were performed using shRNA and the selective HDAC inhibitor LMK-235 for HDAC5 knockdown and inhibition in BC cells. The synergistic effects of LMK-235 with the proteasome inhibitor bortezomib were also examined.

Results

HDAC5 was extensively expressed in human BC tissues, and high HDAC5 expression was associated with an inferior prognosis. Knockdown of HDAC5 inhibited cell proliferation, migration, invasion, and enhanced apoptosis. The HDAC5 inhibitor LMK-235 inhibited cell growth and induced apoptosis, while the inclusion of bortezomib synergistically enhanced the efficacy of LMK-235.

Conclusions

Our findings indicate that HDAC5 is a promising prognostic marker and drug target for BC and that the combination of LMK-235 and bortezomib presents a novel therapeutic strategy for BC.

Overexpression of ING5 inhibits HGF-induced proliferation, invasion and EMT in thyroid cancer cells via regulation of the c-Met/PI3K/Akt signaling pathway

The inhibitor of growth 5 (ING5), a novel member of the ING family, is involved in diverse biological processes such as cell growth, apoptosis and DNA repair. Recently, ING5 has been reported to be associated with cancer development. However, its specific role in thyroid cancer has yet to be elucidated. In this study, we found that the expression of ING5 was significantly down-regulated in human thyroid cancer tissues and cell lines. In addition, overexpression of ING5 markedly inhibited hepatocyte growth factor (HGF)-induced proliferation, invasion and epithelial-mesenchymal transition (EMT) of thyroid cancer cells as well as suppressed the tumor growth and metastasis in vivo. Furthermore, our data showed that the c-Met/PI3K/Akt signaling pathway was responsible for the inhibitory effect of ING5 on the thyroid cancer. Taken together, these findings provided an essential basis for the tumor-suppression role of ING5 in thyroid cancer.

HDAC6 regulates microRNA-27b that suppresses proliferation, promotes apoptosis and target MET in diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma. Histone deacetylase 6 (HDAC6) is frequently altered in DLBCL and inhibition of HDAC6 has potent anti-tumor effects in vitro and in vivo. We profiled miRNAs that altered in the HDAC6 knockdown DLBCL cells with NanoString nCounter assay and identified microRNA-27b (miR-27b) as the most significantly increased miRNA. We validated decreased expression of miR-27b in DLBCL tissues, and we found that low expression of miR-27b was associated with poor overall survival of patients with DLBCL. In addition, forced expression of miR-27b suppressed DLBCL cell viability and proliferation in vitro, and inhibited tumor growth in vivo. Mechanistically, Rel A/p65 is found to negatively regulate miR-27b expression, and its acetylation and block of nuclear translocalization caused by HDAC6 inhibition significantly elevates miR-27b expression. Furthermore, miR-27b targets MET and thus represses the MET/PI3K/AKT pathway. These findings highlight an important role of miR-27b in the development of DLBCL and uncover a HDAC6-Rel A/p65-miR-27b-MET signaling pathway. Elevating miR-27b through HDAC6 inhibition would be a promising strategy for DLBCL treatment.

Antitumor effect of Batf2 through IL-12 p40 up-regulation in tumor-associated macrophages

The development of effective treatments against cancers is urgently needed, and the accumulation of CD8⁺ T cells within tumors is especially important for cancer prognosis. Although their mechanisms are still largely unknown, growing evidence has indicated that innate immune cells have important effects on cancer progression through the production of various cytokines. Here, we found that basic leucine zipper transcription factor ATF-like 2 (Batf2) has an antitumor effect. An s.c. inoculated tumor model produced fewer IL-12 p40⁺ macrophages and activated CD8⁺ T cells within the tumors of Batf2^-/- mice compared with WT mice. In vitro studies also revealed that the IL-12 p40 expression was significantly lower in Batf2^-/- macrophages following their stimulation by toll-like receptor ligands, such as R848. Additionally, we found that BATF2 interacts with p50/p65 and promotes IL-12 p40 expression. In conclusion, Batf2 has an antitumor effect through the up-regulation of IL-12 p40 in tumor-associated macrophages, which eventually induces CD8⁺ T-cell activation and accumulation within the tumor.

The DNA methyltransferase inhibitor zebularine exerts antitumor effects and reveals BATF2 as a poor prognostic marker for childhood medulloblastoma

Medulloblastoma (MB) is the most common solid tumor among pediatric patients and corresponds to 20 % of all pediatric intracranial tumors in this age group. Its treatment currently involves significant side effects. Epigenetic changes such as DNA methylation may contribute to its development and progression. DNA methyltransferase (DNMT) inhibitors have shown promising anticancer effects. The agent Zebularine acts as an inhibitor of DNA methylation and shows low toxicity and high efficacy, being a promising adjuvant agent for anti-cancer chemotherapy. Several studies have reported its effects on different types of tumors; however, there are no studies reporting its effects on MB. We analyzed its potential anticancer effects in four pediatric MB cell lines. The treatment inhibited proliferation and clonogenicity, increased the apoptosis rate and the number of cells in the S phase (p < 0.05), as well as the expression of p53, p21, and Bax, and decreased cyclin A, Survivin and Bcl-2 proteins. In addition, the combination of zebularine with the chemotherapeutic agents vincristine and cisplatin resulted in synergism and antagonism, respectively. Zebularine also modulated the activation of the SHH pathway, reducing SMO and GLI1 levels and one of its targets, PTCH1, without changing SUFU levels. A microarray analysis revealed different pathways modulated by the drug, including the Toll-Like Receptor pathway and high levels of the BATF2 gene. The low expression of this gene was associated with a worse prognosis in MB. Taken together, these data suggest that Zebularine may be a potential drug for further in vivo studies of MB treatment.

Targeting Batf2 for infectious diseases and cancer

The family members Batf, Batf2 and Batf3 belong to a class of transcription factors containing basic leucine zipper domains that regulate various immunological functions and control the development and differentiation of immune cells. Functional studies by others demonstrated a predominant role for Batf in controlling Th2 cell functions and lineage development of T lymphocytes as well as a critical role of Batf, Batf2 and Batf3 in CD8α+dendritic cell development. Moreover, Batf family member expression was measured in a vast collection of mouse and human cell types by cap analysis gene expression (CAGE), a recent developed sequencing technology, showing reasonable expression spectrum in immune cells consistent with previously published expression profiles. Batf and Batf3 were highly expressed in lymphocytes and the earlier moderately expressed in myeloid lineages. Batf2 was predominantly expressed in monocytes/macrophages. Functional studies in mice demonstrated that Batf2 has a central role in macrophage activation by regulating inflammatory responses during lipopolysaccharides stimulation and mycobacterial infection. Hence, Batf2 could be used as a biomarker and a potential host directed drug target in tuberculosis. Moreover, Batf2 act as a tumor suppressor gene and augmenting Batf2 in malignant cells might be an encouraging therapeutic treatment against cancer.

SARI inhibits angiogenesis and tumour growth of human colon cancer through directly targeting ceruloplasmin

SARI, also called as BATF2, belongs to the BATF family and has been implicated in cancer cell growth inhibition. However, the role and mechanism of SARI in tumour angiogenesis are elusive. Here we demonstrate that SARI deficiency facilitates AOM/DSS-induced colonic tumorigenesis in mice. We show that SARI is a novel inhibitor of colon tumour growth and angiogenesis in mice. Antibody array and HUVEC-related assays indicate that VEGF has an essential role in SARI-controlled inhibition of angiogenesis. Furthermore, Co-IP/PAGE/mass spectrometry indicates that SARI directly targets ceruloplasmin (Cp), and induces protease degradation of Cp, thereby inhibiting the activity of the HIF-1α/VEGF axis. Tissue microarray results indicate that SARI expression inversely correlates with poor clinical outcomes in colon cancer patients. Collectively, our results indicate that SARI is a potential target for therapy by inhibiting angiogenesis through the reduction of VEGF expression and is a prognostic indicator for patients with colon cancer.

Regulation of the MET oncogene: molecular mechanisms

The MET oncogene is a predictive biomarker and an attractive therapeutic target for various cancers. Its expression is regulated at multiple layers via various mechanisms. It is subject to epigenetic modifications, i.e. DNA methylation and histone acetylation. Hypomethylation and acetylation of the MET gene have been associated with its high expression in some cancers. Multiple transcription factors including Sp1 and Ets-1 govern its transcription. After its transcription, METmRNA is spliced into multiple species in the nucleus before being transported to the cytoplasm where its translation is modulated by at least 30 microRNAs and translation initiation factors, e.g. eIF4E and eIF4B. METmRNA produces a single chain pro-Met protein of 170 kDa which is cleaved into α and β chains. These two chains are bound together through disulfide bonds to form a heterodimer which undergoes either N-linked or O-linked glycosylation in the Golgi apparatus before it is properly localized in the membrane. Upon interactions with its ligand, i.e. hepatocyte growth factor (HGF), the activity of Met kinase is boosted through various phosphorylation mechanisms and the Met signal is relayed to downstream pathways. The phosphorylated Met is then internalized for subsequent degradation or recycle via proteasome, lysosome or endosome pathways. Moreover, the Met expression is subject to autoregulation and activation by other EGFRs and G-protein coupled receptors. Since deregulation of the MET gene leads to cancer and other pathological conditions, a better understanding of the MET regulation is critical for Met-targeted therapeutics.