RIOK2 Inhibitor NSC139021 Exerts Anti-Tumor Effects on Glioblastoma via Inducing Skp2-Mediated Cell Cycle Arrest and Apoptosis

Increased Expression and Prognostic Significance of BYSL in Melanoma

We evaluated the BYSL content and underlying mechanism in melanoma (SKCM) overall survival (OS). In this study, we used a comprehensive approach combining bioinformatics tools, including miRNA estimation, quantitative real-time polymerase chain reaction (qRT-PCR) of miRNAs, E3 ligase estimation, STRING analysis, TIMER analysis, examination of associated upstream modulators, protein-protein interaction (PPI) analysis, as well as retrospective and survival analyses, alongside clinical sample validation. These methods were used to investigate the content of BYSL, its methylation status, its relation to patient outcome, and its immunologic significance in tumors. Our findings revealed that BYSL expression is negatively regulated by BYSL methylation. Analysis of 468 cases of SKCM RNA sequencing samples demonstrated that enhanced BYSL expression was associated with higher tumor grade. We identified several miRNAs, namely hsa-miR-146b-3p, hsa-miR-342-3p, hsa-miR-511-5p, hsa-miR-3690, and hsa-miR-193a-5p, which showed a strong association with BYSL levels. Furthermore, we predicted the E3 ubiquitin ligase of BYSL and identified CBL, FBXW7, FZR1, KLHL3, and MARCH1 as potential modulators of BYSL. Through our investigation, we discovered that PNO1, RIOK2, TSR1, WDR3, and NOB1 proteins were strongly associated with BYSL expression. In addition, we found a close association between BYSL levels and certain immune cells, particularly dendritic cells (DCs). Notably, we observed a significant negative correlation between miR-146b-3p and BYSL mRNA expression in SKCM sera samples. Collectively, based on the previously shown evidences, BYSL can serve as a robust bioindicator of SKCM patient prognosis, and it potentially contributes to immune cell invasion in SKCM.

A role for RIO kinases in the crosshair of cancer research and therapy

RIO (right open reading frame) family of kinases including RIOK1, RIOK2 and RIOK3 are known for their role in the ribosomal biogenesis. Dysfunction of RIO kinases have been implicated in malignancies, including acute myeloid leukemia, glioma, breast, colorectal, lung and prostatic adenocarcinoma suggesting RIO kinases as potential targets in cancer. In vitro, in vivo and clinical studies have demonstrated that RIO kinases are overexpressed in various types of cancers suggesting important roles in tumorigenesis, especially in metastasis. In the context of malignancies, RIO kinases are involved in cancer-promoting pathways including AKT/mTOR, RAS, p53 and NF-κB and cell cycle regulation. Here we review the role of RIO kinases in cancer development emphasizing their potential as therapeutic target and encouraging further development and investigation of inhibitors in the context of cancer.

Targeted inhibition of the methyltransferase SETD8 synergizes with the Wee1 inhibitor adavosertib in restraining glioblastoma growth

Despite intense research efforts, glioblastoma remains an incurable brain tumor with a dismal median survival time of 15 months. Thus, identifying new therapeutic targets is an urgent need. Here, we show that the lysine methyltransferase SETD8 is overexpressed in 50% of high-grade gliomas. The small molecule SETD8 inhibitor UNC0379, as well as siRNA-mediated inhibition of SETD8, blocked glioblastoma cell proliferation, by inducing DNA damage and activating cell cycle checkpoints. Specifically, in p53-proficient glioblastoma cells, SETD8 inhibition and DNA damage induced p21 accumulation and G1/S arrest whereas, in p53-deficient glioblastoma cells, DNA damage induced by SETD8 inhibition resulted in G2/M arrest mediated by Chk1 activation. Checkpoint abrogation, by the Wee1 kinase inhibitor adavosertib, induced glioblastoma cell lines and primary cells, DNA-damaged by UNC0379, to progress to mitosis where they died by mitotic catastrophe. Finally, UNC0379 and adavosertib synergized in restraining glioblastoma growth in a murine xenograft model, providing a strong rationale to further explore this novel pharmacological approach for adjuvant glioblastoma treatment.

RIOK2 Contributes to Cell Growth and Protein Synthesis in Human Oral Squamous Cell Carcinoma

Ribosomes are responsible for the protein synthesis that maintains cellular homeostasis and is required for the rapid cellular division of cancer cells. However, the role of ribosome biogenesis mediators in the malignant behavior of tongue squamous cell carcinoma (TSCC) is unknown. In this study, we found that the expression of RIOK2, a key enzyme involved in the maturation steps of the pre-40S ribosomal complex, was significantly associated with poorer overall survival in patients with TSCC. Further, multivariate analysis revealed that RIOK2 is an independent prognostic factor (hazard ratio, 3.53; 95% confidence interval, 1.19-10.91). Inhibition of RIOK2 expression by siRNA decreased cell growth and S6 ribosomal protein expression in oral squamous cell carcinoma cell lines. RIOK2 knockdown also led to a significant decrease in the protein synthesis in cancer cells. RIOK2 has potential application as a novel therapeutic target for TSCC treatment.

APY0201 Represses Tumor Growth through Inhibiting Autophagy in Gastric Cancer Cells

Gastric cancer (GC) is one of the most common cancers globally. There are currently few effective chemotherapeutic drugs available for GC patients. The inhibitors of phosphatidylinositol kinase containing an FYVE finger structure (PIKfyve) have shown significant anticancer effects in several types of cancers, but their effectiveness in GC remains unknown. In this study, we investigate the effect of APY0201, an inhibitor of PIKfyve, on GC tumor growth and its mechanism of action. It was found that APY0201 inhibited GC cell proliferation in in vitro GC cell model, organoid model, and in vivo xenograft tumor model. Through analyzing cell autophagy, we found that APY0201 might block autophagic flux by impairing lysosome degradation function of GC cells, inducing the accumulation of autophagosomes, thus causing the inhibition of GC cell proliferation. We also found that APY0201 induced G1/S phase arrest in GC cells. Importantly, APY0201 was also effective in inducing repression of autophagy and cell cycle arrest in the mouse tumor xenograft. Our results suggest that APY0201 could be a new promising therapeutic option for GC.

Editorial of the Special Issue “Targeted Therapies for Cancer”

Cancer, the second leading cause of death worldwide, continues to represent an impressive challenge for researchers and clinicians [...]