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Inflammatory cytokines, components of cancer stem cells (CSCs) niche, could affect the characteristics of CSCs such as self-renewal and metastasis. Interleukin-17 (IL-17) is a new pro-inflammatory cytokine mainly produced by T-helper (Th17) cells and macrophages. The effects of IL-17 on the characteristics of CSCs remain to be explored. Here we first demonstrated a role of IL-17 in promoting the self-renewal of ovarian CD133+ cancer stem-like cells (CSLCs). We detected IL-17-producing cells (CD4+ cells and CD68+ macrophages) in the niche of CD133+CSLCs. Meanwhile, there was IL-17 receptor expression on CD133+CSLCs derived from A2780 cell line and primary ovarian cancer tissues. By recombinant human IL-17 stimulation and IL-17 transfection, the growth and sphere formation capacities of ovarian CD133+CSLCs were significantly enhanced in a dose-dependent manner. Moreover, ovarian CD133+CSLCs transfected with IL-17 showed greater tumorigenesis capacity in nude mice. These data suggest that IL-17 promoted the self-renewal of ovarian CD133+CSLCs. Further investigation through gene profiling revealed that the stimulation function of IL-17 on self-renewal of ovarian CD133+CSLCs might be mediated by the nuclear factor (NF)-κB and p38 mitogen-activated protein kinases (MAPK) signaling pathway. NF-κB and p38 MAPK were activated by IL-17. More importantly, IL-17-promoted self-renewal was inhibited by specific inhibitors of NF-κB and p38 MAPK. Taken together, our data indicate that IL-17 contributed to ovarian cancer malignancy through promoting the self-renewal of CD133+CSLCs and that IL-17 and its signaling pathway might serve as therapeutic targets for the treatment of ovarian cancer. [ABSTRACT FROM AUTHOR]

Highly desmoplastic and immunosuppressive tumor microenvironment (TME) in pancreatic ductal adenocarcinoma (PDAC) contributes to tumor progression and resistance to current therapies. Clues targeting the notorious stromal environment have offered hope for improving therapeutic response whereas the underlying mechanism remains unclear. Here, we find that prognostic microfibril associated protein 5 (MFAP5) is involved in activation of cancer-associated fibroblasts (CAFs). Inhibition of MFAP5 high CAFs shows synergistic effect with gemcitabine-based chemotherapy and PD-L1-based immunotherapy. Mechanistically, MFAP5 deficiency in CAFs downregulates HAS2 and CXCL10 via MFAP5/RCN2/ERK/STAT1 axis, leading to angiogenesis, hyaluronic acid (HA) and collagens deposition reduction, cytotoxic T cells infiltration, and tumor cells apoptosis. Additionally, in vivo blockade of CXCL10 with AMG487 could partially reverse the pro-tumor effect from MFAP5 overexpression in CAFs and synergize with anti-PD-L1 antibody to enhance the immunotherapeutic effect. Therefore, targeting MFAP5 high CAFs might be a potential adjuvant therapy to enhance the immunochemotherapy effect in PDAC via remodeling the desmoplastic and immunosuppressive microenvironment., (© 2023. The Author(s).)

RORγt is a master regulator of Th17 cells. Despite evidence linking RORγt deficiency/inhibition with metastatic thymic T cell lymphomas, the role of RORγt in lymphoma metabolism is unknown. Chronic alcohol consumption plays a causal role in many human cancers. The risk of T cell lymphoma remains unclear in humans with alcohol use disorders (AUD) after chronic RORγt inhibition. Here we demonstrated that alcohol consumption accelerates RORγt deficiency-induced lymphomagenesis. Loss of RORγt signaling in the thymus promotes aerobic glycolysis and glutaminolysis and increases allocation of glutamine carbon into lipids. Importantly, alcohol consumption results in a shift from aerobic glycolysis to glutaminolysis. Both RORγt deficiency- and alcohol-induced metabolic alterations are mediated by c-Myc, as silencing of c-Myc decreases the effects of alcohol consumption and RORγt deficiency on glutaminolysis, biosynthesis, and tumor growth in vivo. The ethanol-mediated c-Myc activation coupled with increased glutaminolysis underscore the critical role of RORγt-Myc signaling and translation in lymphoma., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Non-small cell lung cancer (NSCLC) is a fatal disease, and its metastatic process is poorly understood. Although aberrant methylation is involved in tumor progression, the mechanisms underlying dynamic DNA methylation remain to be elucidated. It is significant to study the molecular mechanism of NSCLC metastasis and identify new biomarkers for NSCLC early diagnosis. Here, we performed MeDIP-seq and hMeDIP-seq analyses to detect the genes regulated by dynamic DNA methylation. Comparison of the 5mC and 5hmC sites revealed that the CD147 gene underwent active demethylation in NSCLC tissues compared with normal tissues, and this demethylation upregulated CD147 expression. Significantly high levels of CD147 expression and low levels of promoter methylation were observed in NSCLC tissues. Then, we identified the CD147 promoter as a target of KLF6, MeCP2, and DNMT3A. Treatment of cells with TGF-β triggered active demethylation involving loss of KLF6/MeCP2/DNMT3A and recruitment of Sp1, Tet1, TDG, and SMAD2/3 transcription complexes. A dCas9-SunTag-DNMAT3A-sgCD147-targeted methylation system was constructed to reverse CD147 expression. The targeted methylation system downregulated CD147 expression and inhibited NSCLC proliferation and metastasis in vitro and in vivo. Accordingly, we used cfDNA to detect the levels of CD147 methylation in NSCLC tissues and found that the CD147 methylation levels exhibited an inverse relationship with tumor size, lymphatic metastasis, and TNM stage. In conclusion, this study clarified the mechanism of active demethylation of CD147 and suggested that the targeted methylation of CD147 could inhibit NSCLC invasion and metastasis, providing a highly promising therapeutic target for NSCLC., (© 2022. The Author(s).)

Metastasis is responsible for the death of most breast cancer patients. Robo1 has been implicated as a tumor suppressor for various cancers including breast cancer. However, it is not well understood how Robo1 expression is regulated during tumorigenesis. In this study, we uncovered that the transmembrane proline rich γ-carboxyglutamic acid protein 4 (PRRG4) promotes breast cancer metastasis by downregulating Robo1. Analysis of mRNA expression data in The Cancer Genome Atlas and immunohistochemistry assay on breast tumor samples showed that PRRG4 expression was higher in breast tumors than in normal breast tissues. Experiments with PRRG4 knockdown and overexpression revealed that PRRG4 promoted migration and invasion of breast cancer cells, and enhanced metastasis in an experimental metastasis model. Mechanistically, we found that PRRG4 via its LPSY and PPPY motifs recruited the E3 ubiquitin ligase NEDD4, which induced ubiquitination and degradation of Robo1, thus contributing to migration and invasion of breast cancer cells. In addition, PRRG4 interacted with and enhanced protein tyrosine kinase Src and FAK activation. Overall, our data support a model that PRRG4 via NEDD4 downregulates the Robo1, resulting in the activation of Src and FAK and promoting breast cancer metastasis. PRRG4 may be a novel target for treating metastatic breast cancer.

DNA polymerase β (Pol β) plays a critical role in DNA base excision repair (BER), which is involved in maintaining genomic stability and in the modulation of DNA demethylation. Numerous studies implicated deficiency of Pol β in the genomic instability and dysregulation of genes expression, leading to affecting initiation of cancer. However, the role of Pol β in cancer progression is still unclear. Here, we show that Pol β depresses migratory and invasive capabilities of both breast and lung carcinomas, which were evident in human breast and lung cancer cells, as well as in mouse xenograft tumors. On the molecular basis, overexpression of Pol β enhanced expression of CDH13, which show function on cell adhesion and migration. Knockdown of CDH13 restores the migratory, invasive capabilities and angiogenesis in tumor, which gets impaired by Pol β. According to the function of BER on modulation of DNA demethylation, our studies on CDH13 expression and the DNA methylation levels of CDH13 promoter suggested that Pol β promotes expression of CDH13 by augmenting DNA demethylation of CDH13 promoter. Our findings elucidated a novel possibility that Pol β impair cancer cell metastasis during cancer progression and shed light on the role of Pol β in cancer therapy.

Discerning oncogenic drivers from passengers remain a major effort in understanding of the essence of the initiation and development of hepatocellular carcinoma (HCC), which is the most common primary liver malignancy and the third leading cause of cancer mortality worldwide. Here we report that ZNF774, a novel zinc-finger protein, inhibits the proliferation and invasion of HCC cells. Molecular characterization of this protein indicated that ZNF774 acts as a transcription repressor, and interrogation of ZNF774 interactome by affinity purification-coupled mass spectrometry revealed that ZNF774 is physically associated with the Mi-2/nucleosome remodeling and deacetylase (NuRD) complex in cells. Genome-wide identification of the transcriptional targets of the ZNF774/NuRD complex by ChIP-seq indicated that ZNF774 represses a cohort of genes including NOTCH2 that are critically involved in the growth and mobility of HCC. We demonstrated that the ZNF774/NuRD complex inhibits the proliferation and invasion of HCC cells in vitro and suppresses HCC growth and metastasis in vivo. Importantly, the expression of ZNF774 is significantly downregulated in HCC, and low ZNF774 expression strongly correlated with high NOTCH2 expression, advanced pathological stages, and poor overall survival of the patients. Together, these results uncover a key role for the ZNF774/NuRD-NOTCH2 axis in hepatocarcinogenesis.

An increased DNA repair capacity is associated with drug resistance and limits the efficacy of chemotherapy in breast cancers. Flap endonuclease 1 (FEN1) participates in various DNA repair pathways and contributes to cancer progression and drug resistance in chemotherapy. Inhibition of FEN1 serves as a potent strategy for cancer therapy. Here, we demonstrate that microRNA-140 (miR-140) inhibits FEN1 expression via directly binding to its 3' untranslated region, leading to impaired DNA repair and repressed breast cancer progression. Overexpression of miR-140 sensitizes breast cancer cells to chemotherapeutic agents and overcomes drug resistance in breast cancer. Notably, ectopic expression of FEN1 abates the effects of miR-140 on DNA damage and the chemotherapy response in breast cancer cells. Furthermore, the transcription factor/repressor Ying Yang 1 (YY1) directly binds to the miR-140 promoter and activates miR-140 expression, which is attenuated in doxorubicin resistance. Our results demonstrate that miR-140 acts as a tumor suppressor in breast cancer by inhibiting FEN1 to repress DNA damage repair and reveal miR-140 to be a new anti-tumorigenesis factor for adjunctive breast cancer therapy. This novel mechanism will enhance the treatment effect of chemotherapy in breast cancer.

MicroRNAs (miRNAs) have been shown to be involved in the progression and tumor microenvironment of glioblastoma multiforme (GBM). Our previous research has indicated that miR-340-5p has an antitumor effect in vitro. However, the role of miR-340-5p in GBM has not been fully elucidated. Here, we show that downregulation of miR-340-5p in GBM is correlated with tumor size, recurrence, and poor survival. Moreover, we found that miR-340-5p levels are correlated with the density of tumor-associated macrophages (TAMs) and M2-polarized TAMs in GBM. Biofunctional investigations revealed that downregulation of miR-340-5p promoted TAM recruitment and M2-TAMs polarization in vitro and in vivo. In addition, we found that upregulation of miR-340-5p inhibited tumor growth and was associated with good prognosis in vivo. Through gene expression profiles and bioinformatics analysis, we showed that miR-340-5p directly targets POSTN, which recruited TAMs through integrin αvβ3. Downregulation of miR-340-5p in GBM did not induce the differentiation of TAMs into polarized M2 cells but was able to promote the M2 polarization of TAMs through directly targeting LTBP-1. Furthermore, we found that M2-TAMs promoted tumorigenesis and were associated with a poor prognosis in vivo. In an in vitro study, we demonstrated that M2-TAMs inhibited miR-340-5p expression in GBM cells by upregulation of TGFβ-1, which increased HMGA-2 expression in GBM. A ChIP assay confirmed that HMGA-2 transcriptionally suppressed miR-340-5p expression. Patients with low-miR-340-5p expression, high CD163, high POSTN, high LIBP1 levels, and high HMGA-2 had a poor prognosis with shorter overall survival, confirming data from the TCGA database. These findings suggest that an miR-340-5p-macrophage feedback loop modulates the progression and tumor microenvironment of GBM and may represent a prognostic biomarker and therapeutic strategy for GBM.

P14/p19ARF (ARF) plays a major role in the activation of p53 by oncogenic signals. The biochemical basis of this has not been fully elucidated. We report here that forced expression of p14ARF enhances phosphorylation of p53 serine 15 (p53S15) in NIH3T3, IMR90 and MCF7 cells. Ectopic expression of the oncogenes c-myc, E2F1 and E1A, all of which activate p53 at least partially via ARF, lead to p53S15 phosphorylation in IMR90 cells. In addition, ectopic expression of p53 also results in p53S15 phosphorylation, suggesting that this is a common event in the ARF-p53 tumor suppression system. Furthermore, p53-, p14ARF-, c-myc- and E2F1-, but not E1A-, induced p53S15 phosphorylation was substantially reduced in AT fibroblasts (GM05823). Downregulation of ATM in MCF7 cells using RNA interference (RNAi) technology significantly attenuated p14ARF- and p53-induced phosphorylation of p53S15. Ectopically expressed ARF in NIH3T3 cells induced ATM nuclear foci and activated ATM kinase. Functionally, ectopic expression of p14ARF and c-myc inhibited the proliferation of IMR90 but not ATM null GM05823 cells, and p14ARF-induced inhibition of MCF7 cell proliferation was significantly attenuated by downregulation of ATM by RNAi. Taken together, these data show a functional role for ATM in ARF-mediated tumor suppression.

Acute promyelocytic leukemia (APL) is characterized by the expansion of malignant myeloid cells blocked at the promyelocytic stage of hemopoietic development, and is associated with reciprocal chromosomal translocations always involving the retinoic acid receptor alpha (RARalpha) gene on chromosome 17. As a consequence of the translocation RARalpha variably fuses to the PML, PLZF, NPM and NUMA genes (X genes), leading to the generation of RARalpha-X and X-RARalpha fusion genes. The aberrant chimeric proteins encoded by these genes may exert a crucial role in leukemogenesis. Retinoic acid (RA), a metabolite of vitamin A, can overcome the block of maturation at the promyelocytic stage and induce the malignant cells to terminally mature into granulocytes resulting in complete albeit transient disease remission. APL has become, for this reason, the paradigm for 'cancer differentiation therapy'. Furthermore, APL associated with translocation between the RARalpha and the PLZF genes (PLZF-RARalpha) shows a distinctly worse prognosis with poor response to chemotherapy and little or no response to treatment with RA, thus defining a new APL syndrome. Here we will focus our attention on the recent progresses made in defining the molecular mechanisms underlying the pathogenesis of this paradigmatic disease in vivo in the mouse. We will review the critical contribution of mouse modeling in unraveling the transcriptional basis for the differential response to RA in APL. We will also discuss how this new understanding has allowed to propose, develop and test in these murine leukemia models as well as in human APL patients novel therapeutic strategies.

The IGF2 gene, which encodes a growth factor, is subject to genomic imprinting. The frequently observed loss of IGF2 imprinting in a variety of tumors has been suggested to contribute to neoplasia. Since these reports have not documented the imprinting status of IGF2 at the cellular level, it cannot be excluded that the imprinting status might vary within the tumor. The possibility that loss of IGF2 imprinting in neoplastic cells reflects random imprinting patterns, was therefore addressed. We show here that individual cell populations of the JEG-3 choriocarcinoma cell line display heterogenous imprinting patterns of both IGF2 and H19. In addition, a lack of correlation between IGF2 and H19 imprinting status suggests that any regional parental imprint has been functionally lost. This notion is reinforced by the observation that JEG-3 cell subclones display a range of promoter-specific IGF2 allele usage. Moreover, we observed that the imprinting status of H19 and IGF2 were differentially modulated in JEG-3-derived tumors generated in nude mice. The results suggest that allele-specific expression of IGF2 operates in the absence of a parental imprint. Finally, our observations urge caution with respect to the general interpretation of biallelic expression as 'loss of imprinting'.