Brn3a/Pou4f1 Functions as a Tumor Suppressor by Targeting c-MET/STAT3 Signaling in Thyroid Cancer

Xihuang pill facilitates glioma cell pyroptosis via the POU4F1/STAT3 axis

Glioma is the most common malignancy in the central nervous system. This study aims to disclose the impacts of Xihuang pill (XHP), a traditional Chinese formula, on glioma cell pyroptosis and relevant molecular mechanism. U251 and SHG-44 cells were treated with XHP alone or together with oe-POU4F1 and sh-STAT3. CCK8 assay detected the viability, flow cytometry evaluated pyroptosis, and microscopy observed cell morphology. LDH release was determined by the LDH kit and the levels of IL-1β and IL-18 were detected by ELISA. Immunofluorescence showed NLRP3 expression in glioma cells and western blotting measured the levels of POU4F1, STAT3, NLRP3, ASC, cleaved caspase-1, and IL-1β. The binding of POU4F1 to STAT3 was verified. Primary glioma model was established to observe tumor change by in vivo imaging, determine the levels of Ki67 and NLRP3 by immunochemistry, and detect relevant protein levels by western blotting. XHP treatment alone downregulated POU4F1 and STAT3 levels, aroused pyroptotic appearance in glioma cells such as ballooning swelling, reduced cell viability and number of pyroptotic cells, increased LDH release and IL-1β and IL-18 levels, formed NLRP3 sports in cells, and elevated the levels of pyroptosis-related proteins. However, POU4F1 overexpression or STAT3 silencing suppressed XHP-promoted pyroptosis. Mechanistically, POU4F1 acted as a transcription factor of STAT3 and regulated its transcription. In primary glioma models, XHP enhanced glioma cell pyroptosis and blocked glioma growth. XHP facilitates glioma cell pyroptosis via the POU4F1/STAT3 axis.

Combination of Radiosensitivity Gene Signature and PD-L1 Status Predicts Clinical Outcome of Patients With Locally Advanced Head and Neck Squamous Cell Carcinoma: A Study Based on The Cancer Genome Atlas Dataset

Aim: The aim of our study was to investigate the potential predictive value of the combination of radiosensitivity gene signature and PD-L1 expression for the prognosis of locally advanced head and neck squamous cell carcinoma (HNSCC).

Methods: The cohort was selected from The Cancer Genome Atlas (TCGA) and classified into the radiosensitive (RS) group and radioresistant (RR) group by a radiosensitivity-related gene signature. The cohort was also grouped as PD-L1-high or PD-L1-low based on PD-L1 mRNA expression. The least absolute shrinkage and selection operator (lasso)-based Cox model was used to select hub survival genes. An independent validation cohort was obtained from the Gene Expression Omnibus (GEO) database.

Results: We selected 288 locally advanced HNSCC patients from TCGA. The Kaplan–Meier method found that the RR and PD-L1-high group had a worse survival than others (p = 0.033). The differentially expressed gene (DEG) analysis identified 553 upregulated genes and 486 downregulated genes (p < 0.05, fold change >2) between the RR and PD-L1-high group and others. The univariate Cox analysis of each DEG and subsequent lasso-based Cox model revealed five hub survival genes (POU4F1, IL34, HLF, CBS, and RNF165). A further hub survival gene-based risk score model was constructed, which was validated by an external cohort. We observed that a higher risk score predicted a worse prognosis (p = 0.0013). The area under the receiver operating characteristic curve (AUC) plots showed that this risk score model had good prediction value (1-year AUC = 0.684, 2-year AUC = 0.702, and 3-year AUC = 0.688). Five different deconvolution methods all showed that the B cells were lower in the RR and PD-L1-high group (p < 0.05). Finally, connectivity mapping analysis showed that the histone deacetylase (HDAC) inhibitor trichostatin A might have the potential to reverse the phenotype of RR and PD-L1-high in locally advanced HNSCC (p < 0.05, false discovery rate <0.1).

Conclusion: The combination of 31-gene signature and the PD-L1 mRNA expression had a potential predictive value for the prognosis of locally advanced HNSCC who had RT. The B cells were lower in the RR and PD-L1-high group. The identified risk gene signature of locally advanced HNSCC and the potential therapeutic drug trichostatin A for the RR and PD-L1-high group are worth being further studied in a prospective homogenous cohort.

Functions and Targets of miR-335 in Cancer

MicroRNAs (miRNAs) are small non-coding RNAs (18~25 nt in length) that act as master regulators of eukaryotic gene expression. They might play an oncogenic or tumor-suppressive role in multiple cancers. In recent decades, several studies have focused on the functions and mechanisms of miR-335 in cancer. The expression level of miR-335 in tissues and cells varies with cancer types, and miR-335 has been proposed as a potential biomarker for the prognosis of cancer. Besides, miR-335 may serve as an oncogene or tumor suppressor via regulating different targets or pathways in tumor initiation, development, and metastasis. Furthermore, miR-335 also influences tumor microenvironment and drug sensitivity. MiR-335 is regulated by various factors such as lncRNAs and microRNAs. In this review, we reveal the functions and targets of miR-335 in various cancers and its potential application as a possible biomarker in prognostic judgment and treatment of malignant tumors.

POU4F1 confers trastuzumab resistance in HER2-positive breast cancer through regulating ERK1/2 signaling pathway

Over-expression of the human epidermal growth factor receptor-2 (HER2) is related to aggressive tumors and poor prognosis in breast cancer. Trastuzumab (TRA) resistance leads to tumor recurrence and metastasis, resulting in poor prognosis in HER2-positive breast cancer. POU Class 4 Homeobox 1 (POU4F1) is a member of the POU domain family transcription factors, and has a key role in regulating cancers. However, its effects on TRA-resistant HER2-positive breast cancer are still vague. In the present study, we found that POU4F1 expression was dramatically increased in clinical breast cancer specimens with TRA resistance. Higher POU4F1 was also detected in HER2-positive breast cancer cells with TRA resistance than that of the parental ones. Poor prognosis was detected in breast cancer patients with high POU4F1 expression. Under TRA treatment, POU4F1 knockdown significantly reduced the proliferative capacity of HER2-positive breast cancer cells with TRA resistance. POU4F1 silence also sensitized resistant HER-positive breast cancer cells to TRA treatment in vivo using a xenograft mouse model, along with the markedly reduced tumor growth rate and tumor weight. Moreover, we found that POU4F1 deletion greatly decreased the activation of mitogen-activated or extracellular signal-regulated protein kinase kinases 1 and 2 (MEK1/2) and extracellular-regulated kinase 1/2 (ERK1/2) signaling pathways in breast cancer cells with TRA resistance. Migration and invasion were also effectively hindered by POU4F1 knockdown in TRA-resistant HER2-positive breast cancer cells. Notably, we found that POU4F1 deletion-improved chemosensitivity of HER2-positive breast cancer cells with drug-resistance to TRA treatment was closely associated with the blockage of ERK1/2 signaling. Collectively, our findings reported a critical role of POU4F1 in regulating TRA resistance, and demonstrated the underlying molecular mechanisms in HER2-positive breast cancer. Thus, POU4F1 may be a promising prognostic and therapeutic target to develop effective treatment for overcoming TRA resistance.