Tumor-associated NK cells drive MDSC-mediated tumor immune tolerance through the IL-6/STAT3 axis.

Apart from their killer identity, natural killer (NK) cells have integral roles in shaping the tumor microenvironment. Through immune gene deconvolution, the present study revealed an interplay between NK cells and myeloid-derived suppressor cells (MDSCs) in nonresponders of immune checkpoint therapy. Given that the mechanisms governing the outcome of NK cell-to-myeloid cell interactions remain largely unknown, we sought to investigate the cross-talk between NK cells and suppressive myeloid cells. Upon contact with tumor-experienced NK cells, monocytes and neutrophils displayed increased expression of MDSC-related suppressive factors along with increased capacities to suppress T cells. These changes were accompanied by impaired antigen presentation by monocytes and increased ER stress response by neutrophils. In a cohort of patients with sarcoma and breast cancer, the production of interleukin-6 (IL-6) by tumor-infiltrating NK cells correlated with S100A8/9 and arginase-1 expression by MDSCs. At the same time, NK cell-derived IL-6 was associated with tumors with higher major histocompatibility complex class I expression, which we further validated with b2m-knockout (KO) tumor mice models. Similarly in syngeneic wild-type and IL-6 KO mouse models, we then demonstrated that the accumulation of MDSCs was influenced by the presence of such regulatory NK cells. Inhibition of the IL-6/signal transducer and activator of transcription 3 (STAT3) axis alleviated suppression of T cell responses, resulting in reduced tumor growth and metastatic dissemination. Together, these results characterize a critical NK cell-mediated mechanism that drives the development of MDSCs during tumor immune escape.

Canonical WNT signaling-dependent gating of MYC requires a noncanonical CTCF function at a distal binding site.

Abnormal WNT signaling increases MYC expression in colon cancer cells in part via oncogenic super-enhancer-(OSE)-mediated gating of the active MYC to the nuclear pore in a poorly understood process. We show here that the principal tenet of the WNT-regulated MYC gating, facilitating nuclear export of the MYC mRNA, is regulated by a CTCF binding site (CTCFBS) within the OSE to confer growth advantage in HCT-116 cells. To achieve this, the CTCFBS directs the WNT-dependent trafficking of the OSE to the nuclear pore from intra-nucleoplasmic positions in a stepwise manner. Once the OSE reaches a peripheral position, which is triggered by a CTCFBS-mediated CCAT1 eRNA activation, its final stretch (≤0.7 µm) to the nuclear pore requires the recruitment of AHCTF1, a key nucleoporin, to the CTCFBS. Thus, a WNT/ß-catenin-AHCTF1-CTCF-eRNA circuit enables the OSE to promote pathological cell growth by coordinating the trafficking of the active MYC gene within the 3D nuclear architecture.

Silencing Y-box binding protein-1 inhibits triple-negative breast cancer cell invasiveness via regulation of MMP1 and beta-catenin expression.

Y-box binding protein-1 (YB-1), an important transcription and translation regulator protein, is known to increase cancer cell invasiveness and spreading. Here, we report its role in breast cancer, particularly in mediating cell invasion in triple-negative breast cancer (TNBC). YB-1 stable knockdown (shYB-1) significantly reduced the invasive potential of MDA-MB-231 TNBC cells in 2D and 3D (spheroid) cultures. Whole proteome mass spectrometry analysis showed an enrichment of cell adhesion and cell to matrix interaction proteins, notably, matrix metalloproteinase-1 (MMP1) and beta-catenin (CTNNB1), which are known to play critical roles in cancer metastasis. shYB-1 cells exhibited substantial downregulation of MMP1 and CTNNB1 mRNA and protein expression, with reduced MMP1 enzyme activity. YB-1 was also observed to bind to the promoter of MMP1 and overexpression of MMP1 plasmid in shYB-1 cells increased cell invasion. Finally, analysis of tumour samples from the Gene Expression-Based Outcome for Breast Cancer Online (GOBO) database revealed that high gene expressions of YBX1, MMP1 and CTNNB1 predict for a significantly lower 10-year distant metastasis free survival. Altogether, this study shows that YB-1 mediates breast cancer invasion and metastasis via regulation of MMP1 and beta-catenin.

A-kinase anchor protein 12 (AKAP12) inhibits cell migration in breast cancer.

A-kinase anchor protein 12 (AKAP12) also known as Gravin and SSeCKS, is a novel potent scaffold protein for many key signaling factors, such as protein kinase C (PKC), PKA, cyclins as well as F-actin. AKAP12 expression is known to be suppressed in several human malignancies including breast, prostate, gastric and colon cancers. In this study, we evaluated the role of AKAP12 in the migration of breast cancer cells, an important cellular process in cancer progression. AKAP12 gene expression was analyzed in human breast cancer tissues using the Gene expression-based Outcome for Breast cancer Online (GOBO) database and TissueScan array, followed by relapse free survival (RFS) analysis with the Kaplan-Meier Plotter. AKAP12 protein was then analyzed in normal MCF10A breast cell line and six different breast cancer cell lines (AU565, Hs578T, MCF7, MDA-MB-231, T47D and ZR751). After which, siRNA-mediated knockdown of AKAP12 was carried out in MCF10A, MDA-MB-231 and Hs578T cells, followed by phenotypic assays. AKAP12 was observed to be reduced in breast cancer tissues as analyzed by GOBO and TissueScan array. Kaplan Meier survival analysis revealed that patients with AKAP12 gene expression had a higher RFS survival. There was also decreased AKAP12 protein expression in breast cancer cell lines compared to MCF10A normal epithelial breast cell line. Knockdown of AKAP12 in both MCF10A cells and Hs578T cells induced cell migration but did not alter cell proliferation. Moreover, siAKAP12 in aggressive MDA-MB-231 breast cancer cells led to an increase in cell migration. Immunofluorescence analysis of AKAP12 depleted MCF10A cells also revealed formation of thick stress fibers which could affect cell migration. Hence, the findings in this study suggest that AKAP12 is a potential metastasis suppressor in breast cancer.

Y-box binding protein-1 and STAT3 independently regulate ATP-binding cassette transporters in the chemoresistance of gastric cancer cells.

Y-box binding protein-1 (YB-1) facilitates cancer chemoresistance through the upregulation of ATP-binding cassette (ABC) transporters associated with multidrug resistance, which is one of the primary obstacles in cancer treatment. Since aberrant Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling is also implicated in chemoresistance in numerous human malignancies, the interaction between YB-1 and JAK/STAT signaling was explored underlying the chemoresistance of NUGC3 gastric cancer cells. It was demonstrated that YB-1 translocated into the nuclei of NUGC3 cells exposed to doxorubicin hydrochloride, suggesting its important role in chemoresistance. Consistently, knockdown of YB-1 significantly decreased the chemoresistance of cells to doxorubicin hydrochloride and epirubicin hydrochloride, as evidenced by a decrease in cell viability. Notably, JAK inhibitor AG490 treatment further decreased the cell viability caused by YB-1 inhibition and doxorubicin hydrochloride. It was also observed that YB-1 transcriptionally regulated the ABCC3 transporter, whereas STAT3 modulated ABCC2 transporter levels. These findings suggest that YB-1 and STAT3 act together to facilitate chemoresistance via modulating the expression of different ABC transporters in NUGC3 cells. Notably, siYB-1 did not exhibit any significant effect on STAT3 expression. Similarly, siSTAT3 failed to alter YB-1 expression, suggesting that the two may not regulate each other in a mutual manner. However, double knockdown of YB-1 and STAT3 led to a synergistic inhibition of cell invasion in NUGC3 cells. Nonetheless, the combined treatment of YB-1 antagonists with STAT3 inhibitors may serve as an effective therapy in gastric cancer.

Potential adverse effects of engineered nanomaterials commonly used in food on the miRNome.

The emergence of nanotechnology has greatly impacted our daily lives. Multiple products, including cosmetics, pharmaceuticals, electronics and food, are produced with incorporation of nanomaterials (NMs). Nanotechnology has yielded many promising benefits, yet, there remains much uncertainty about the hazards of NMs to humans. Hence, it is important to ensure safety of the users. Although many in vitro and in vivo studies have been carried out on the potential toxicity generated by NMs in food, its effects on the microRNA genome (miRNome) involved in the regulation of gene expression have been poorly understood. Therefore, this review focuses on the types of commonly used NMs (containing silicon dioxide, titanium dioxide, silver or zinc oxide) in food products and their potential toxic effects, including how NMs can induce epigenetic toxicity mediated via altered miRNA expression.

YBX1 gene silencing inhibits migratory and invasive potential via CORO1C in breast cancer in vitro.

BACKGROUND: Y-box binding protein-1 is an evolutionary conserved transcription and translation regulating protein that is overexpressed in various human malignancies, including breast cancer. Despite reports of YB-1 and its association with distant spread of breast cancer, the intrinsic mechanism underlying this observation remains elusive. This study investigates the role of YB-1 in mediating metastasis in highly invasive breast cancer cell lines. METHODS: Silencing the YBX1 gene (which encodes the YB-1 protein) by small interfering RNA (siRNA) was performed in MDA-MB-231 and Hs578T breast cancer cell lines, followed by phenotypic assays including cell migration and invasion assays. Gene expression profiling using Affymetrix GeneChip® Human Transcriptome 2.0 array was subsequently carried out in YB-1 silenced MDA-MB-231 cells. Overexpression and silencing of YBX1 were performed to assess the expression of CORO1C, one of the differentially regulated genes from the transcriptomic analysis. A Gaussia luciferase reporter assay was used to determine if CORO1C is a putative YB-1 downstream target. siRNA-mediated silencing of CORO1C and down-regulation of YBX1 in CORO1C overexpressing MDA-MB-231 cells were performed to evaluate cell migration and invasion. RESULTS: Downregulation of the YB-1 protein inhibited cell migration and invasion in MDA-MB-231 breast cancer cells. Global gene expression profiling in the YBX1 silenced MDA-MB-231 cells identified differential expression of several genes, including CORO1C (which encodes for an actin binding protein, coronin-1C) as a potential downstream target of YB-1. While knockdown of YBX1 gene decreased CORO1C gene expression, the opposite effects were seen in YB-1 overexpressing cells. Subsequent verification using the reporter assay revealed that CORO1C is an indirect downstream target of YB-1. Silencing of CORO1C by siRNA in MDA-MB-231 cells was also observed to reduce cell migration and invasion. Silencing of YBX1 caused a similar reduction in CORO1C expression, concomitant with a significant decrease in migration in Hs578T cells. In coronin-1C overexpressing MDA-MB-231 cells, increased migration and invasion were abrogated by YB-1 knockdown. CONCLUSION: It would appear that YB-1 could regulate cell invasion and migration via downregulation of its indirect target coronin-1C. The association between YB-1 and coronin-1C offers a novel approach by which metastasis of breast cancer cells could be targeted and abrogated.

miR-93 inhibits the invasive potential of triple-negative breast cancer cells in vitro via protein kinase WNK1.

Despite advances in treatment, the highly metastatic nature of breast tumors has given rise to the urgent need for development of novel therapeutic and prognostic markers. miR-93 is known to regulate the epithelial to mesenchymal transition process and to influence metastatic spread in breast carcinoma, although the exact mechanism(s)/genes involved remain unknown. In the present study, we examined the role of miR-93 in MDA-MB-231 breast cancer cells. Overexpression of mature miR-93-5p in MDA-MB-231 cells decreased cell migratory capability and invasive potential, as well as increased adhesion. In contrast, inhibition of miR-93 induced the opposite effects. miRNA-mRNA target prediction (TargetScan) identified WNK lysine deficient protein kinase 1 (WNK1), which is known to interact with diverse signaling pathways and regulate cell proliferation, survival, angiogenesis and metastasis, as one of the potential targets of miR-93. Furthermore, we showed by luciferase assay that WNK1 is a putative miR-93 target. siRNA mediated silencing of WNK1 also decreased the invasive ability of the cells, suggesting that the effects of miR-93 may be attributed at least in part to decreased WNK1 expression. Further in vivo studies are required to ascertain the miR-93-WNK1-metastasis cascade, that has potential implications in breast cancer therapy.

Peripheral nerve proteins as potential autoantigens in acute and chronic inflammatory demyelinating polyneuropathies.

Guillain-Barré syndrome is classified into acute inflammatory demyelinating polyneuropathy and acute motor axonal neuropathy. Whereas autoantibodies to GM1 or GD1a induce the development of acute motor axonal neuropathy, pathogenic autoantibodies have yet to be identified in acute inflammatory demyelinating polyneuropathy and chronic inflammatory demyelinating polyneuropathy. This review highlights the importance of autoantibodies to peripheral nerve proteins in the physiopathology of acute and chronic inflammatory demyelinating polyneuropathies. Moreover, we listed up other potential antigens, which may become helpful biomarkers for acquired, dysimmune demyelinating neuropathies based on their critical functions during myelination and their implications in hereditary demyelinating neuropathies.