FOXM1 Promotes Non-Small Cell Lung Cancer Progression by Increasing CHEK1 Expression

OBJECTIVE

Non-small cell lung cancer (NSCLC) is a leading cause of cancer-associated mortality. This study aimed to investigate the role of checkpoint kinase 1 (CHEK1) in NSCLC progression and its regulatory relationship with forkhead box protein M1 (FOXM1).

METHODS

Transwell assays were used to evaluate the migration and invasion capabilities of NSCLC cells with either CHEK1 overexpression or knockdown. The expression of epithelial-mesenchymal transition (EMT) markers in NSCLC cells under CHEK1 overexpression or knockdown conditions was analyzed via Western blotting. Proliferative capacity was assessed using CCK-8 assays in NSCLC cells with modulated CHEK1 expression. Additionally, real-time quantitative PCR was employed to measure CHEK1 and FOXM1 expression levels in NSCLC tissues. The effects of CHEK1 knockdown on tumor growth were further validated in animal models. The binding of FOXM1 to the CHEK1 promoter region was examined using dual-luciferase reporter assays and chromatin immunoprecipitation (ChIP) assays.

RESULTS

FOXM1 and CHEK1 were upregulated in NSCLC tissues. CHEK1 overexpression promoted NSCLC cell proliferation, while its knockdown suppressed proliferation, inhibited EMT, and reduced tumor growth in vivo. FOXM1 was shown to directly bind to CHEK1 promoter, thereby upregulating CHEK1 expression.

CONCLUSION

CHEK1 promotes NSCLC cell proliferation and tumor growth, and its expression is regulated by FOXM1. These findings suggest CHEK1 and FOXM1 are potential therapeutic targets for NSCLC treatment.

Cell cycle-based antibody selection for suppressing cancer cell growth

Cell cycle arrest and programmed cell death are crucial biological processes in cancer development. Regulating cell fate decisions is essential due to their potential to induce cell cycle arrest and cell death. Inducing cell cycle regulatory proteins in tumor cells is considered a key objective in cancer therapy. Here, we present a novel method that selects antibodies from an antibody library to inhibit cancer growth using fluorescence-activated cell sorting (FACS) assays and cell cycle analysis. This approach seeks antibodies that induce cancer cells to enter the G0 or G1 phase, a quiescent state where cells cease to proliferate and trigger programmed cell death. We found that the T1 antibody effectively suppresses the proliferation of cancer cells. Mechanistically, serine protease 3 (PRSS3) is a target antigen of the T1 antibody. We demonstrated that PRSS3 controls tumor cell proliferation and apoptosis through interaction with the T1 antibody. This research suggests that PRSS3 holds great potential as a target for solid cancer treatment. This cycle-based approach to antibody screening shows potential because it can be broadly applied to cancer and other challenging diseases.

An Antagonist Antibody That Inhibits Cancer Cell Growth In Vitro through RACK1

BACKGROUND/OBJECTIVES

Our research introduces a novel screening method to identify antibodies that can suppress cell proliferation and induce apoptosis.

METHODS

By using an autocrine signaling system with lentivirus, we developed an antibody screening method based on FACS sorting assays and cell cycle analysis to inhibit tumor growth in vitro. This approach is particularly well suited for studying tumor suppressors. Inducing the G0 phase in tumor cells with specific antibodies may arrest their growth permanently or trigger apoptosis. The cell cycle is composed of tightly regulated phases for cell growth and division, with tumorigenesis or apoptosis occurring when these regulatory mechanisms fail.

RESULTS

In our study, we identified RACK1 as a key regulator of cancer cell growth. The H9 antibody against RACK1 selected from a human antibody library effectively suppressed cell proliferation by inhibiting RACK1 function.

CONCLUSIONS

These findings suggest that RACK1 plays a crucial role in tumor cell cycling and could represent a novel therapeutic target for cancer treatment. Although RACK1 is recognized as a significant target protein in various tumors, no commercial therapeutic agents currently exist. Our results suggest that the H9 antibody could be a promising candidate for the development of novel cancer therapies.

Effects of Ochratoxin A exposure on DNA damage in porcine granulosa cells in vitro

Ochratoxin A (OTA), a feed mycotoxin, tends to impair the reproductive performance of animals. Our previous studies have demonstrated that OTA exposure inhibits porcine ovarian granulosa cell (GC) proliferation and induces their apoptosis, but the underlying toxic mechanism is still uncertain. In this study, we explored the OTA exposure on porcine GCs in vitro and found that OTA exposure inhibited the proliferation of porcine GCs and arrested cell cycle of GCs in the G2/M phase. The results based on RNA-Seq revealed that 20 μM and 40 μM OTA exposure increase DNA damage of porcine GCs in vitro. The differentially expressed genes (DEGs) of 40 μM OTA exposure were enriched in the pathways of mismatch repair, nucleotide excision repair and homologous recombination in DNA replication compared with control group and 20 μM OTA exposure group. Meanwhile, OTA exposure increased the expression levels of DNA double-strand breaks (DSBs) gene γ-H2AX, and DNA repair related genes, such as BRCA1, XRCC1, PARP1, and RAD51. Above all, our research revealed that OTA might exert deleterious effects on porcine ovarian GCs, influencing DNA repair-related biological processes and causing DNA damage response.

Resveratrol analog, N-(4-methoxyphenyl)-3,5-dimethoxybenzamide induces G2/M phase cell cycle arrest and apoptosis in HeLa human cervical cancer cells

In this study, several resveratrol analogs were synthesized and evaluated in search of a more effective anti-proliferative resveratrol analog. Among the evaluated resveratrol analogs, we have identified N-(4-methoxyphenyl)-3,5-dimethoxybenamide (MPDB) as a potent anti-proliferative compound. Treatment with MPDB resulted in G₂/M phase cell cycle arrest, which was accompanied by alteration of G₂/M-related protein expression and phosphorylation. MPDB-induced G₂/M arrest was blocked by transfection of ATM/ATR siRNAs, indicating the critical role of ATM/ATR in G₂/M phase arrest. In addition, treatment with MPDB displayed the activation of caspase and decreased Bcl-xl protein expression after 20 h in HeLa cells. Moreover, MPDB increased cytosolic cytochrome c release and Fas and Fas-L protein expression, indicating intrinsic and extrinsic apoptosis pathway, respectively. These results suggest that MPDB is a new and potent compound that induces ATM/ATR-dependent G₂/M phase cell cycle arrest and apoptosis, implicating it as a putative candidate in the investment of cervical cancer therapy.

Increased radiosensitivity of HPV-positive head and neck cancers: Molecular basis and therapeutic perspectives

Human papillomavirus driven head and neck squamous cell carcinoma (HNSCC), particularly oropharyngeal squamous cell carcinoma (OPSCC), are characterized by a significant survival advantage over their HPV-negative counterparts. Although the reasons behind this are still not fully elucidated, it is widely accepted that these tumors have a higher response to ionizing radiation that might explain their favorable outcomes. Potential underlying intrinsic mechanisms include impaired DNA repair abilities, differences in activated repopulation-signaling pathways and cell cycle control mechanisms. The role of the microenvironment is increasingly highlighted, particularly tumor oxygenation and the immune response. Recent studies have shown a distinct pattern of intratumoral immune cell infiltrates, according to HPV status, and have suggested that an increased cytotoxic T-cell based antitumor immune response is involved in improved prognosis of patients with HPV-positive OPSCC. These significant milestones, in the understanding of HPV-induced HNSCC, pave the way to new therapeutic opportunities. This article reviews the current evidence on the biological basis of increased radiosensitivity in HPV-positive HNSCC and discusses potential therapeutic implications.

[Cell cycle and molecular targets: CDK inhibition]

Protein phosphorylation is a fundamental post-translational modification. It regulates a large number of critical cellular processes (differentiation, division, proliferation, apoptosis). Cell division is a process including a series of phases by which a parent cell divides into two daughter cells. The cells enter these stages then progress within the cell division under an accurate control by many proteins. These proteins are activated by phosphorylation. Cyclin-dependent kinases are responsible for this phosphorylation and therefore represent potential therapeutic targets especially in oncology.