TRIM14 suppressed the progression of NSCLC via hexosamine biosynthesis pathway.

Tripartite Motif 14 (TRIM14) is an oncoprotein that belongs to the E3 ligase TRIM family, which is involved in the progression of various tumors except for non-small-cell-lung carcinoma (NSCLC). However, little is currently known regarding the function and related mechanisms of TRIM14 in NSCLC. Here, we found that the TRIM14 protein was downregulated in lung adenocarcinoma tissues compared with the adjacent tissues, which can suppress tumor cell proliferation and migration both in vitro and in vivo. Moreover, TRIM14 can directly bind to glutamine fructose-6-phosphate amidotransferase 1 (GFAT1), which in turn results in the degradation of GFAT1 and reduced O-glycosylation levels. GFAT1 is a key enzyme in the rate-limiting step of the hexosamine biosynthetic pathway (HBP). Replenishment of N-Acetyl-D-glucosamine can successfully reverse the inhibitory effect of TRIM14 on the NSCLC cell growth and migration as expected. Collectively, our data revealed that TRIM14 suppressed NSCLC cell proliferation and migration through ubiquitination and degradation of GFAT1, providing a new regulatory role for TRIM14 on HBP.

Upregulated Long Non-coding RNA Lnc-MRPL39-2:1 Induces the Growth and Invasion of Nasopharyngeal Carcinoma by Binding to HuR and Stabilizing ß-Catenin mRNA.

Long non-coding RNAs (lncRNAs) have been to regulate tumor progression and therapy resistance through various molecular mechanisms. In this study, we investigated the role of lncRNAs in nasopharyngeal carcinoma (NPC) and the underlying mechanism. Using lncRNA arrays to analyze the lncRNA profiles of the NPC and para-tumor tissues, we detected the novel lnc-MRPL39-2:1, which was validated by in situ hybridization and by the 5' and 3' rapid amplification of the cDNA ends. Further, its role in NPC cell growth and metastasis was verified in vitro and in vivo. The researchers conducted the RNA pull-down assays, mass spectrometry (MS), dual-luciferase reporter assays, RNA immunoprecipitation (RIP) assays, and the MS2-RIP assays were then used to identify the lnc-MRPL39-2:1-interacting proteins and miRNAs. We found that lnc-MRPL39-2:1, which was highly expressed in in NPC tissues, was related to a poor prognosis in NPC patients. Furthermore, lnc-MRPL39-2:1 was shown to induce the growth and invasion of NPC by interacting directly with the Hu-antigen R (HuR) to upregulate ß-catenin expression both in vivo and in vitro. Lnc-MRPL39-2:1 expression was also suppressed by microRNA (miR)-329. Thus, these findings indicate that lnc-MRPL39-2:1 is essential in NPC tumorigenesis and metastasis and highlight its potential as a prognostic marker and therapeutic target for NPC.

PD-L1 expression as biomarker of efficacy of PD-1/PD-L1 checkpoint inhibitors in metastatic triple negative breast cancer: A systematic review and meta-analysis.

Background: Inhibitors of programmed cell death 1 (PD-1)/programmed cell death ligand 1(PD-L1) checkpoint have been approved for metastatic triple negative breast cancer (mTNBC) in patients positive for PD-L1 expression. Negative results from the recent phase III trials (IMPassion131 and IMPassion132) have raises questions on the efficacy of PD-1/PD-L1 checkpoint inhibitors and the predictive value of PD-L1 expression. Here we attempt to systematically analyze the biomarker value of PD-L1 expression for predicting the response of PD-1/PD-L1 checkpoint inhibitors in mTNBC. Materials and methods: PubMed database was searched until Dec 2021 for studies evaluating PD-1/PD-L1 checkpoint inhibitors plus/minus chemotherapy in mTNBC. Outcome of interest included objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). Review Manager (RevMan) version 5.4. was used for data-analysis. Results: In total, 20 clinical trials comprising 3962 mTNBC patients (ICT: 2665 (67%); CT: 1297 (33%) were included in this study. Overall ORR was 22% (95%CI, 14-30%) and significant improvement was observed for PD-L1+ patients (ORR 1.78 [95%CI, 1.45-2.19], p<0.00001) as compared to PD-L1- cohort. Pooled outcome also indicated a significant 1-year PFS and 2-year OS advantage for patients with PD-L1 expression (1-year PFS: ORR 1.39 [95%CI, 1.04-1.85], p=0.02; I2 = 0%; 2-year OS: (ORR 2.47 [95%CI, 1.30-4.69], p=0.006; I2 = 63%). Subgroup analysis indicated that PD-L1 expression can successfully predict tumor response and 2-year OS benefit in mTNBC patients regardless of the type of investigating agent, line of treatment administration, and to some extent the type of treatment. Biomarker ability of PD-L1 expression to predict 1-year PFS was slightly better with pembrolizumab (p=0.09) than atezolizumab (p=0.18), and significantly better when treatment was administered in the first-line setting (OR 1.38 [95%CI, 1.02-1.87], p=0.04) and chemotherapy was added (OR 1.38 [95%CI, 1.02-1.86], p=0.03). Immune-related toxicity of any grade and grade≥3 was 39% (95%CI, 26%-52%) and 10% (95%CI, 8%-13%), respectively. Conclusions: PD-L1 expression can predict objective response rate and 2-year OS in mTNBC patients receiving PD-1/PD-L1 checkpoint inhibitors. One-year PFS is also predicted in selected patients. PD-L1 expression can be a useful biomarker of efficacy of PD-1/PD-L1 checkpoint inhibitors in mTNBC.

Exosomal B7-H4 from irradiated glioblastoma cells contributes to increase FoxP3 expression of differentiating Th1 cells and promotes tumor growth.

BACKGROUND: Glioblastoma (GBM) is the most common and aggressive form of primary brain tumor. Although numerous postoperative therapeutic strategies have already been developed, including radiotherapy, tumors inevitably recur after several years of treatment. The coinhibitory molecule B7-H4 negatively regulates T cell immune responses and promotes immune escape. Exosomes mediate intercellular communication and initiate immune evasion in the tumor microenvironment (TME). OBJECTIVE: This study aimed to determine whether B7-H4 is upregulated by radiation and loaded into exosomes, thus contributing to immunosuppression and enhancing tumor growth. METHODS: Iodixanol density-gradient centrifugation and flow cytometry were used to verify exosomal B7-H4. Naïve T cells were differentiated into Th1 cells, with or without exosomes. T cell-secreted cytokines and markers of T cell subsets were measured. Mechanistically, the roles of B7-H4, and ALIX in GBM were analyzed using databases and tissue samples. Co-immunoprecipitation, and pull-down assays were used to tested the direct interactions between ATM and ALIX or STAT3. In vitro ATM kinase assays, western blotting, and site-directed mutation were used to assess ATM-mediated STAT3 phosphorylation. Finally, the contribution of exosomal B7-H4 to immunosuppression and tumor growth was investigated in vivo. RESULTS: Exosomes from irradiated GBM cells decreased the anti-tumor immune response of T cell in vitro and in vivo via delivered B7-H4. Mechanistically, irradiation promoted exosome biogenesis by increasing the ATM-ALIX interaction. Furthermore, the ATM-phosphorylated STAT3 was found to directly binds to the B7-H4 promoter to increase its expression. Finally, the radiation-induced increase in exosomal B7-H4 induced FoxP3 expression during Th1 cell differentiation via the activated STAT1 pathway. In vivo, exosomal B7-H4 decreased the radiation sensitivity of GBM cells, and reduced the survival of GBM mice model. CONCLUSION: This study showed that radiation-enhanced exosomal B7-H4 promoted immunosuppression and tumor growth, hence defining a direct link between irradiation and anti-tumor immune responses. Our results suggest that co-administration of radiotherapy with anti-B7-H4 therapy could improve local tumor control and identify exosomal B7-H4 as a potential tumor biomarker.

Pyroptosis relates to tumor microenvironment remodeling and prognosis: A pan-cancer perspective.

Background and aim: Pyroptosis is an inflammatory form of programmed cell death implicated in inflammation and disease. Moreover, inducing pyroptosis has been appreciated as anti-cancer therapy for its ability to unleash anti-cancer immune responses. Methods: Utilizing the data available in The Cancer Genome Atlas (TCGA), pyroptosis-related genes' (PRGs) expression, genomic aberrations, and clinical significance were systematically analyzed in pan-cancer. A GSVA score was obtained to rate pyroptosis level and divide the cancers into pyroptosis-low and pyroptosis-high groups. Immunohistochemistry (IHC) was used to evaluate the differential expression of major PRGs (GSDMC, GSDMD, GSDME, NLRP3, NLRC4, IL1B) in selected tumor types (COAD, HNSC, KIRC, LIHC, LUAD, LUSC). Selection of tumors for immunohistochemistry (IHC) was based on their expression pattern in TCGA cancers, clinical relevance, tumor epidemiology, and sample availability. Results: Differential expression of PRGs was evident in various cancers and associated with prognosis which was driven by genomic variations and epigenetic abnormalities, such as single nucleotide variations (SNVs), copy number variation (CNV) and DNA methylation level. For example, methylation of PRGs in lower grade glioma (LGG), uveal melanoma (UVM) and kidney renal clear cell carcinoma (KIRC) were predictive of improved survival as upregulation of PRGs was risky in these cancers. Pyroptosis level significantly differentiated tumor from normal samples in 15 types of cancers, exhibited a progressive trend with cancer stage, observed variation among cancer subtypes, and showed a significant association with cancer prognosis. Higher pyroptosis level was associated with worst prognosis in majority of the cancers in terms of OS (KIRC, LGG, and UVM), PFS (GBM, KIRC, LGG, PRAD, THCA, and THYM) and DSS (KIRC and LGG) as estimated by Kaplan-Meier survival curves. Moreover, Pyroptosis level was strongly indicative of a hot tumor immune microenvironment with high presence of CD8+ T cell and other T cell subtypes. Several oncogenic pathways, such as P53 pathway, DNA repair, KRAS signaling, epithelial-mesenchymal transition (EMT), IL6 JAK STAT3 signaling, IL2 STAT5 signaling, PI3K AKT MTOR signaling and angiogenesis, were enriched in pyroptosis-hi subgroups across cancers. Conclusions: Genetic alterations in PRGs greatly influence the pyroptosis level and cancer prognosis. A relatively hot tumor immune microenvironment was associated with pyroptosis irrespective of the cancer prognosis. Overall, our study reveals the critical role of pyroptosis in cancer and highlights pyroptosis-based therapeutic vulnerabilities.

PLK1 Inhibition Sensitizes Breast Cancer Cells to Radiation via Suppressing Autophagy.

PURPOSE: Polo-like kinase 1 (PLK1) is a protein kinase that is overexpressed in breast cancer and may represent an attractive target for breast cancer treatment. However, few studies have investigated the relationship between PLK1 and radiosensitivity in breast cancer. Here, we attempted to explore whether PLK1 inhibition could sensitize breast cancer cells to radiation. METHODS AND MATERIALS: Breast cancer cells were treated with PLK1 small interference RNA or the PLK1-inhibitor, GSK461364. Cell proliferation was assessed using a colony formation assay. Cell cycle analyses were performed by flow cytometry. DNA damage, autophagy, and reactive oxygen species induced by ionizing radiation were detected by immunofluorescence, Western blot, and flow cytometry, respectively. Microtubule-associated protein 1 light chain 3 alpha (LC3) puncta were detected using an immunofluorescence assay. A clonogenic survival assay was used to determine the effect of PLK1 inhibition on cell radiosensitivity. A xenograft mouse model of breast cancer cells was used to investigate the potential synergistic effects of PLK1 inhibition and irradiation in vivo. Finally, the expression of PLK1 and LC3 in the breast cancer tissues was evaluated by immunohistochemistry. RESULTS: PLK1 inhibition significantly suppressed the proliferation and increased the radiosensitivity of breast cancer cells. Pharmacologic inhibition of PLK1 by the selective inhibitor, GSK461364, enhanced the radiosensitivity of breast cancer cells in vivo (n = 4, P = .002). Mechanistically, PLK1 inhibition led to the downregulation of radiation-induced reactive oxygen species and autophagy, thereby increasing the radiosensitivity of breast cancer cells. Additionally, we detected a positive correlation between the expression of PLK1 and LC3 in human breast cancer samples (n = 102, R = 0.486, P = .005). CONCLUSIONS: Our findings indicate that PLK1 inhibition enhances the radiosensitivity of breast cancer cells in a manner associated with the suppression of radiation-induced autophagy. The inhibition of PLK1 represents a promising strategy for radiosensitizing breast cancer.

AIMP3 inhibits cell growth and metastasis of lung adenocarcinoma through activating a miR-96-5p-AIMP3-p53 axis.

Aminoacyl-tRNA synthetase-interacting multifunctional protein-3 (AIMP3) is a tumour suppressor, however, the roles of AIMP3 in non-small cell lung cancer (NSCLC) are not explored yet. Here, we reported that AIMP3 significantly inhibited the cell growth and metastasis of NSCLC (lung adenocarcinoma) in vitro and in vivo. We have firstly identified that AIMP3 was down-regulated in human NSCLC tissues compared with adjacent normal lung tissues using immunohistochemistry and western blot assays. Overexpression of AIMP3 markedly suppressed the proliferation and migration of cancer cells in a p53-dependent manner. Furthermore, we observed that AIMP3 significantly suppressed tumour growth and metastasis of A549 cells in xenograft nude mice. Mechanically, we identified that AIMP3 was a direct target of miR-96-5p, and we also observed that there was a negative correlation between AIMP3 and miR-96-5p expression in paired NSCLC clinic samples. Ectopic miR-96-5p expression promoted the proliferation and migration of cancer cells in vitro and tumour growth and metastasis in vivo which partially depended on AIMP3. Taken together, our results demonstrated that the axis of miR-96-5p-AIMP3-p53 played an important role in lung adenocarcinoma, which may provide a new strategy for the diagnosis and treatment of NSCLC.

microRNA-124 inhibits stem-like properties and enhances radiosensitivity in nasopharyngeal carcinoma cells via direct repression of expression of JAMA.

Cancer stem cells (CSCs) are a source of tumour recurrence in patients with nasopharyngeal carcinoma (NPC); however, the function of microRNA-124 (miR-124) in NPC CSCs has not been clearly defined. In this study, we investigated the role of miR-124 in NPC CSCs. qRT-PCR was performed to measure miR-124 expression in NPC tissues and cell lines and the effects of miR-124 on stem-like properties and radiosensitivity of NPC cells measured. Luciferase reporter assays and rescue experiments were used to investigate the interaction of miR-124 with the 3'UTR of junctional adhesion molecule A (JAMA). Finally, we examined the effects of miR-124 in an animal model and clinical samples. Down-regulation of miR-124 was detected in cancer tissues and was inversely associated with tumour stage and lymph node metastasis. Overexpression of miR-124 inhibited stemness properties and enhanced radiosensitivity of NPC cells in vitro and in vivo via targeting JAMA. Up-regulation of miR-124 was correlated with superior overall survival of patients with NPC. Our study demonstrates that miR-124 can inhibit stem-like properties and enhance radiosensitivity by directly targeting JAMA in NPC. These findings provide novel insights into the molecular mechanisms underlying therapy failure in NPC.

EHF promotes colorectal carcinoma progression by activating TGF-ß1 transcription and canonical TGF-ß signaling.

ETS homologous factor (EHF) plays a critical function in epithelial cell differentiation and proliferation. However, the roles of EHF in cancer remain largely unknown. In the present study, we investigated the expression levels, precise function and mechanism of EHF in colorectal carcinoma (CRC). We observed significantly elevated EHF expression in CRC cell lines and tissues. EHF overexpression correlated positively with poor differentiation, advanced T stage, and shorter overall survival of CRC patients. Function experiments revealed that EHF overexpression promoted CRC cell proliferation, migration, and invasion in vitro and in vivo. Mechanistically, EHF could directly upregulate transforming growth factor ß1 (TGF-ß1) expression at the transcription level, thereby activating canonical TGF-ß signaling. Our findings provide novel insights into the mechanisms of EHF in tumorigenesis, invasion, and metastasis of CRC, which may help to provide new therapeutic targets for CRC intervention.

Nuclear lncRNA HOXD-AS1 suppresses colorectal carcinoma growth and metastasis via inhibiting HOXD3-induced integrin ß3 transcriptional activating and MAPK/AKT signalling.

BACKGROUND: Long noncoding RNAs (lncRNAs) have been indicated to play critical roles in cancer development and progression. LncRNA HOXD cluster antisense RNA1 (HOXD-AS1) has recently been found to be dysregulated in several cancers. However, the expression levels, cellular localization, precise function and mechanism of HOXD-AS1 in colorectal carcinoma (CRC) are largely unknown. METHODS: Real-time PCR and in situ hybridization were used to detect the expression of HOXD-AS1 in CRC tissue samples and cell lines. Gain- and loss-of-function experiments were performed to investigate the biological roles of HOXD-AS1 in CRC cell line. RNA pull down, RNA immunoprecipitation and chromatin immunoprecipitation assays were conducted to investigate the mechanisms underlying the functions of HOXD-AS1 in CRC. RESULTS: We observed that HOXD-AS1 was located in the nucleus of CRC cells and that nuclear HOXD-AS1 was downregulated in most CRC specimens and cell lines. Lower levels of nuclear HOXD-AS1 expression were associated with poor outcomes of CRC patients. HOXD-AS1 downregulation enhanced proliferation and migration of CRC cells in vitro and facilitated CRC tumourigenesis and metastasis in vivo. Mechanistic investigations revealed that HOXD-AS1 could suppress HOXD3 transcription by recruiting PRC2 to induce the accumulation of the repressive marker H3K27me3 at the HOXD3 promoter. Subsequently, HOXD3, as a transcriptional activator, promoted Integrin ß3 transcription, thereby activating the MAPK/AKT signalling pathways. CONCLUSION: Our results reveal a previously unrecognized HOXD-AS1-HOXD3-Integrin ß3 regulatory axis involving in epigenetic and transcriptional regulation constitutes to CRC carcinogenesis and progression.

SATB2-AS1 Suppresses Colorectal Carcinoma Aggressiveness by Inhibiting SATB2-Dependent Snail Transcription and Epithelial-Mesenchymal Transition.

Accumulating evidence suggests that long noncoding RNA (lncRNA) plays important regulatory roles in cancer biology. However, the involvement of lncRNA in colorectal carcinoma progression remains largely unknown, especially in colorectal carcinoma metastasis. In this study, we investigated the changes in lncRNA expression in colorectal carcinoma and identified a new lncRNA, the antisense transcript of SATB2 (SATB2-AS1), as a key regulator of colorectal carcinoma progression. SATB2-AS1 was frequently downregulated in colorectal carcinoma cells and tissues, and patients whose tumors expressed SATB2-AS1 at low levels had a shorter overall survival and poorer prognosis. Downregulation of SATB2-AS1 significantly promoted cell proliferation, migration, and invasion in vitro and in vivo, demonstrating that it acts as a tumor suppressor in colorectal carcinoma. SATB2-AS1 suppressed colorectal carcinoma progression by serving as a scaffold to recruit p300, whose acetylation of H3K27 and H3K9 at the SATB2 promoter upregulated expression of SATB2, a suppressor of colorectal carcinoma growth and metastasis. SATB2 subsequently recruited HDAC1 to the Snail promoter, repressing Snail transcription and inhibiting epithelial-to-mesenchymal transition. Taken together, these data reveal SATB2-AS1 as a novel regulator of the SATB2-Snail axis whose loss facilitates progression of colorectal carcinoma. SIGNIFICANCE: These data show that the lncRNA SATB2-AS1 mediates epigenetic regulation of SATB2 and Snail expression to suppress colorectal cancer progression.See related commentary by Li, p. 3536.

Hsp90ab1 stabilizes LRP5 to promote epithelial-mesenchymal transition via activating of AKT and Wnt/ß-catenin signaling pathways in gastric cancer progression.

Hsp90ab1 is upregulated in numerous solid tumors, which is thought to induce the angiogenesis and promote cancer metastasis. However, it's actions in gastric cancer (GC) has not been exhibited. In this study, Hsp90ab1 was demonstrated to be overexpressed and correlated with the poor prognosis, proliferation and invasion of GC. Ectopic expression of Hsp90ab1 promoted the proliferation and metastasis of GC cells both in vitro in cell line models of GC and in vivo using two different xenograft mouse models, while opposite effects were observed in Hsp90ab1 silenced cells. Moreover, the underlining molecular mechanism was explored by the co-immunoprecipitation, immunofluorescence, GST pull-down and in vitro ubiquitination assay. Namely, Hsp90ab1 exerted these functions via the interaction of LRP5 and inhibited ubiquitin-mediated degradation of LRP5, an indispensable coreceptor of the Wnt/ß-catenin signaling pathway. In addition, the crosstalk between Hsp90ab1 and LRP5 contributed to the upregulation of multiple mesenchymal markers, which are also targets of Wnt/ß-catenin. Collectively, this study uncovers the details of the Hsp90ab1-LRP5 axis, providing novel insights into the role and mechanism of invasion and metastasis in GC.

Long noncoding RNA CRNDE stabilized by hnRNPUL2 accelerates cell proliferation and migration in colorectal carcinoma via activating Ras/MAPK signaling pathways.

Recent studies have furthered our understanding of the function of long noncoding RNAs (lncRNAs) in numerous biological processes, including cancer. This study investigated the expression of a novel lncRNA, colorectal neoplasia differentially expressed (CRNDE), in colorectal carcinoma (CRC) tissues and cells by real-time RT-PCR and in situ hybridization, and its biological function using a series of in vitro and in vivo experiments to determine its potential as a prognostic marker and therapeutic target. CRNDE was found to be upregulated in primary CRC tissues and cells (P<0.05), and the upregulation of CRNDE expression is a powerful predictor of advanced TNM stage (P<0.05) and poor prognosis for CRC patients (P=0.002). The promoting effects of CRNDE on the cell proliferation, cell cycling and metastasis of CRC cells were confirmed both in vitro and in vivo by gain-of-function and loss-of-function experiments. Mechanistically, it was demonstrated that CRNDE could form a functional complex with heterogeneous nuclear ribonucleoprotein U-like 2 protein (hnRNPUL2) and direct the transport of hnRNPUL2 between the nucleus and cytoplasm. hnRNPUL2 that was accumulated in the cytoplasm could interact with CRNDE both physically and functionally, increasing the stability of CRNDE RNA. Moreover, gene expression profile data showed that CRNDE depletion in cells downregulated a series of genes involved in the Ras/mitogen-activated protein kinase signaling pathways. Collectively, these findings provide novel insights into the function and mechanism of lncRNA CRNDE in the pathogenesis of CRC and highlight its potential as a therapeutic target for CRC intervention.