Differential expression and prognostic value of TLR4 in kidney renal clear cell carcinoma.

Human Toll-like receptor (TLR) family plays a crucial role in immunity and cancer progression. However, the specific role of human Toll-like receptor 4 (TLR4) in kidney renal clear cell carcinoma (KIRC) remains obscure. Thus, we used single-cell RNA sequencing (RNA-seq) and bulk RNA-seq data combined with in vitro studies to evaluate the expression and prognostic value of TLR4 in KIRC. In our study, we observed that TLR4 was over expressed in KIRC tissues compared to normal renal tissues. And the expression of TLR4 was higher in macrophages/monocytes than other cell types. Besides, there is a close association between TLR4 expression and immune cell infiltration (Neutrophils, Macrophages, T cells and B cells) in KIRC. Immunohistochemical staining also showed that TLR4 was overexpressed in inflammatory infiltration renal tissue compared with normal tissue. Meanwhile, high expression of TLR4 exhibited correlations with improved survival, lower tumor grade and stage. Interestingly, the protective significance of TLR4 only showed in female patients (HR = 0.37, P < 0.01), other than male patients (HR = 0.71, P = 0.08) with KIRC. Consistently, KIRC samples with lymph node metastasis showed lower expression of TLR4. Knockdown of TLR4 in 786-O cell line increased cell proliferation and clonogenic capacity. In summary, this study found TLR4 could inhibit the progression of kidney cancer and was associated with improved survival in KIRC. The overexpression of TLR4 in macrophages and the close association between TLR4 and immune cell infiltration also underline the critical role of TLR4 in building the immune microenvironment for kidney cancer. These results may offer insights into the mechanism and immune microenvironment of kidney cancer.

Screening protective miRNAs and constructing novel lncRNAs/miRNAs/mRNAs networks and prognostic models for triple-negative breast cancer.

Triple-negative breast cancer (TNBC) represents 10-20 % of all breast cancer (BC) cases and is characterized by poor prognosis. Given the urgent need to improve prognostication and develop specific therapies for TNBC, the identification of new molecular targets is of great importance. MicroRNA (miRNA) has been reported as a valuable and novel molecular target in the progression of TNBC. However, the expression and function of miRNAs in different tumors are heterogeneous. Herein, we first analyzed miRNA data from The Cancer Genome Atlas (TCGA) and surprisedly found that overexpressed miRNAs were associated with poor survival in all breast cancer patients, but the overexpressed miRNAs were associated with better survival in TNBC patients. Based on the heterogeneity of miRNA expression in TNBC, we conducted further analysis using univariate Cox proportional hazard regression models and identified 17 miRNAs with prognostic potential. Subsequently, a multivariate Cox model was employed to create a 3-miRNA prognostic model for predicting overall survival in TNBC patients. The diagnostic model exhibited an area under the curve (AUC) of 0.727, and multivariable Cox regression indicated that each covariate was associated with survival. These data indicate that this model is relatively accurate and robust for risk assessment, which have a certain value for clinical application. In order to explore the network behind the overexpressed miRNAs in TNBC, we established a novel network consisting of lncRNAs, miRNAs, and mRNAs through complete transcriptome data from matched samples in the TCGA database. In this network, IRS-1 appeared to be the top hub gene. Experimental results demonstrated that miR-15b-5p and miR-148a-3p effectively target IRS-1 in vitro, shedding light on the intricate regulatory mechanisms in TNBC mediated by the heterogeneous miRNAs. Besides, miR-148a-3p significantly inhibited cell migration and viability. Overall, this study may add valuable insights into the molecular landscape of TNBC based on miRNAs and have the potential to contribute to the development of targeted therapies and improved prognostic strategies of TNBC.

High PGAP3 expression is associated with lymph node metastasis and low CD8+T cell in patients with HER2+ breast cancer.

BACKGROUND: Breast cancer (BC) stands as the most prevalent malignancy among women and ranks as the second most frequently diagnosed cancer globally among newly identified cases. Post-GPI attachment to proteins factor 3（PGAP3）was reported to involve in lipid remodeling. However, its specific role in breast cancer remains inadequately elucidated. Consequently, the principal objective of this study was to investigate the clinical significance of PGAP3 in breast cancer. METHODS: We conducted an extensive analysis using both public databases and our own sample cohort to assess the role of PGAP3 in breast cancer. Immunohistochemistry was employed to assess PGAP3 expression, immune markers, and the co-expression of PGAP3 with key susceptibility genes. Data analysis was performed using the R programming language. RESULTS: Our findings revealed that PGAP3 is significantly overexpressed in breast cancer, particularly in human epidermal growth factor 2 positive (HER2 +) breast cancer cases (p < 0.001). Co-expression analyses demonstrated a significant correlation between PGAP3 and susceptibility genes associated with breast cancer, including BRCA1, BRCA2, PALB2, ATM, CHEK2, RAD51C, and RAD51D (p < 0.05). Logistic regression analysis identified PGAP3 as a significant predictor of estrogen receptor (ER), progesterone receptor (PR), HER2, and lymph node metastasis status (p < 0.01). Furthermore, higher PGAP3 expression was associated with decreased infiltration of CD8 + T cells in breast cancer samples. CONCLUSION: Our study sheds light on the clinical significance of PGAP3 in breast cancer. PGAP3 is not only overexpressed in breast cancer but also correlates with key susceptibility genes, lymph node metastasis, and CD8 + T cell infiltration. These findings provide valuable insights into the potential role of PGAP3 as a biomarker in breast cancer and may contribute to our understanding of the disease's pathogenesis.

Disulfiram/Cu Kills and Sensitizes BRAF-Mutant Thyroid Cancer Cells to BRAF Kinase Inhibitor by ROS-Dependently Relieving Feedback Activation of MAPK/ERK and PI3K/AKT Pathways.

BRAFV600E, the most common genetic alteration, has become a major therapeutic target in thyroid cancer. Vemurafenib (PLX4032), a specific inhibitor of BRAFV600E kinase, exhibits antitumor activity in patients with BRAFV600E-mutated thyroid cancer. However, the clinical benefit of PLX4032 is often limited by short-term response and acquired resistance via heterogeneous feedback mechanisms. Disulfiram (DSF), an alcohol-aversion drug, shows potent antitumor efficacy in a copper (Cu)-dependent way. However, its antitumor activity in thyroid cancer and its effect on cellular response to BRAF kinase inhibitors remain unclear. Antitumor effects of DSF/Cu on BRAFV600E-mutated thyroid cancer cells and its effect on the response of these cells to BRAF kinase inhibitor PLX4032 were systematically assessed by a series of in vitro and in vivo functional experiments. The molecular mechanism underlying the sensitizing effect of DSF/Cu on PLX4032 was explored by Western blot and flow cytometry assays. DSF/Cu exhibited stronger inhibitory effects on the proliferation and colony formation of BRAFV600E-mutated thyroid cancer cells than DSF treatment alone. Further studies revealed that DSF/Cu killed thyroid cancer cells by ROS-dependent suppression of MAPK/ERK and PI3K/AKT signaling pathways. Our data also showed that DSF/Cu strikingly increased the response of BRAFV600E-mutated thyroid cancer cells to PLX4032. Mechanistically, DSF/Cu sensitizes BRAF-mutant thyroid cancer cells to PLX4032 by inhibiting HER3 and AKT in an ROS-dependent way and subsequently relieving feedback activation of MAPK/ERK and PI3K/AKT pathways. This study not only implies potential clinical use of DSF/Cu in cancer therapy but also provides a new therapeutic strategy for BRAFV600E-mutated thyroid cancers.

EGFL7 drives the evolution of resistance to EGFR inhibitors in lung cancer by activating NOTCH signaling.

Accumulating evidence supports evolutionary trait of drug resistance. Like resilience in other systems, most tumor cells experience drug-tolerant state before full resistance acquired. However, the underlying mechanism is still poorly understood. Here, we identify that EGF like domain multiple 7 (EGFL7) is a responsive gene to epidermal growth factor receptor (EGFR) kinase inhibition during a period when tumors are decimated. Moreover, our data reveal that the adaptive increase of EGFL7 during this process is controlled by the depression of nonsense-mediated mRNA decay (NMD) pathway. Upregulation of EGFL7 activates NOTCH signaling in lung cancer cells, which slows down the decrease of c-Myc caused by EGFR inhibition, thereby helping the survival of cancer cells. Our data, taken together, demonstrate that EGFL7 is a driver gene for resistance to EGFR kinase inhibition, and suggest that targeting EGFL7/NOTCH signaling may improve the clinical benefits of EGFR inhibitors in patients with EGFR mutant tumors.

Dipeptidyl Peptidase-4 Stabilizes Integrin α4ß1 Complex to Promote Thyroid Cancer Cell Metastasis by Activating Transforming Growth Factor-Beta Signaling Pathway.

Background: Metastatic disease is a major cause of thyroid cancer-related death. However, the mechanisms responsible for thyroid cancer metastasis are unclear. Dipeptidyl peptidase-4 (DPP4) is a multifunctional cell surface glycoprotein that has been reported to be a negative prognostic factor in thyroid cancer. We explored the molecular mechanism of the role of DPP4 in thyroid cancer cell metastasis. Methods: The effects of DPP4 on thyroid cancer cell migration/invasion in vitro were assessed by transwell assays. A lung metastatic mouse model was also established to determine the effect of DPP4 on tumor metastasis in vivo. DPP4 inhibitor sitagliptin was used to test its effect on thyroid cancer cell metastasis. The mechanism of which DPP4 promotes thyroid cancer cell metastasis was explored by a series of molecular and biochemical experiments. Results: We observed that DPP4 was significantly upregulated in papillary thyroid cancers compared with control subjects, and its expression was positively associated with lymph node metastasis and BRAFV600E mutation. Functional studies showed that DPP4 knockdown significantly inhibited metastatic potential of thyroid cancer cells, and vice versa. However, DPP4 inhibitor sitagliptin did not affect the metastatic ability of thyroid cancer cells, indicating that the promoting effect of DPP4 on tumor metastasis was independent of its enzymatic activity. Mechanistically, DPP4 interacted with the α4 and ß1 integrin subunits, and stabilized the formation of integrin α4ß1 complex. DPP4-mediated integrin signal activation promoted the nuclear localization of c-Jun through the FAK/AKT pathway, thereby inducing the transcription of transforming growth factor-beta 1 (TGFB1 coding for protein TGF-ß1). TGF-ß1 then facilitated tumor metastasis by inducing the epithelial-mesenchymal transition. Conclusions: DPP4 promotes thyroid cancer cell metastasis through the integrins/FAK/AKT/c-Jun/TGF-ß1 signaling axis. These findings may have implications for an alternative therapeutic strategy for thyroid cancer.

The noncoding RNAs SNORD50A and SNORD50B-mediated TRIM21-GMPS interaction promotes the growth of p53 wild-type breast cancers by degrading p53.

Small nucleolar RNA SNORD50A and SNORD50B (SNORD50A/B) has been reported to be recurrently deleted and function as a putative tumor suppressor in different types of cancer by binding to and suppressing the activity of the KRAS oncoproteins. Its deletion correlates with poorer patient survival. However, in this study, we surprisingly found that SNORD50A/B loss predicted a better survival in breast cancer patients carrying wild-type p53. Functional studies showed that SNORD50A/B deletion strongly inhibited the proliferation, migration, invasion and tumorigenic potential, and induced cell cycle arrest and apoptosis in p53 wild-type breast cancer cells, while exerted the opposite effects in p53 mutated breast cancer cells. This was also supported by ectopically expressing SNORD50A/B in both p53 wild-type and mutated breast cancer cells. Mechanistically, SNORD50A/B clearly enhances the interaction between E3 ubiquitin ligase TRIM21 and its substrate GMPS by forming a complex among them, thereby promoting GMPS ubiquitination and its subsequent cytoplasmic sequestration. SNORD50A/B deletion in p53 wild-type breast cancer cells will release GMPS and induce the translocation of GMPS into the nucleus, where GMPS can recruit USP7 and form a complex with p53, thereby decreasing p53 ubiquitination, stabilizing p53 proteins, and inhibiting malignant phenotypes of cancer cells. Altogether, the present study first reports that SNORD50A/B plays an oncogenic role in p53 wild-type breast cancers by mediating TRIM21-GMPS interaction.

Synergistic activation of mutant TERT promoter by Sp1 and GABPA in BRAFV600E-driven human cancers.

The activating TERT promoter mutations and BRAFV600E mutation are well-established oncogenic alterations in human cancers. Coexistence of BRAFV600E and TERT promoter mutations is frequently found in multiple cancer types, and is strongly associated with poor patient prognosis. Although the BRAFV600E-elicited activation of ERK has been demonstrated to contribute to TERT reactivation by maintaining an active chromatin state, it still remains to be addressed how activated ERK is selectively recruited to mutant TERT promoter. Here, we report that transcription factor GABPA mediates the regulation of BRAFV600E/MAPK signaling on TERT reactivation by selectively recruiting activated ERK to mutant TERT promoter, where activated ERK can phosphorylate Sp1, thereby resulting in HDAC1 dissociation and an active chromatin state. Meanwhile, phosphorylated Sp1 further enhances the binding of GABPA to mutant TERT promoter. Taken together, our data indicate that GABPA and Sp1 synergistically activate mutant TERT promoter, contributing to tumorigenesis and cancer progression, particularly in the BRAFV600E-driven human cancers. Thus, our findings identify a direct mechanism that bridges two frequent oncogenic alterations together in TERT reactivation.