ZNF677 inhibits oral squamous cell carcinoma growth and tumor stemness by regulating FOXO3a.

Oral squamous cell carcinoma (OSCC) is a common cancer with an increasing incidence worldwide. Zinc-finger proteins 677 (ZNF677) is involved in the progression and methylation of various cancers, but its role and mechanism in OSCC remain indeterminate. The expression of ZNF677 was analyzed by online database and immunohistochemistry, while the methylation level of ZNF677 was determined by the methylation-specific PCR. The role and mechanism of ZNF677 in the tumor cell growth, migration, invasion and stemness were addressed by cell counting kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU) incorporation, Transwell, wound-healing, sphere‑formation, and western blot assays. In addition, its function was also investigated in a xenografted mice model. The results showed that ZNF677 was lowly expressed in OSCC with a hypermethylation level, which predicted poor overall survival in patients with HNSC. Upregulation of ZNF677 reduced the cell viability, Edu positive cells, numbers of invasion cells, the migration ability, numbers of spheres formation and the expression of proliferation, migration and stemness related proteins in CAL-27 and SCC25 cells. Mechanically, the relative levels of p-AKT/AKT were decreased and the levels of p-FOXO3a/FOXO3a were increased in both cells overexpressed with ZNF677, which were reversed by the SC79 treatment. Moreover, interference of FOXO3a recovered the suppressive effects of ZNF677 overexpression on cell proliferation, migration, invasion and stemness of OSCC cells. Furthermore, overexpression of ZNF677 reduced the tumor volume and weight, and the relative protein level of p-AKT/AKT with an increased level of p-FOXO3a/FOXO3a, and improved pathological symptoms in vivo. Collectively, ZNF677 suppressed OSCC cells growth, migration, invasion and stemness through inhibiting AKT/FOXO3a pathway.

Zhang Z ，Zhang Y ，Hu X ，Chen Y ，Zhuang L ，Zhang S ... -  《Human Cell》

TGFβ induces stemness through non-canonical AKT-FOXO3a axis in oral squamous cell carcinoma.

FOXO3a has been widely regarded as a tumor suppressor. It also plays a paradoxical role in regulating the cancer stem cells (CSCs), responsible for tumor-initiation, chemo-resistance, and recurrence in various solid tumors, including oral squamous cell carcinoma (OSCC). This study aims to uncover the role of FOXO3a and its importance for a non-canonical pathway of TGFβ in regulating the OSCC stemness. We identified FOXO3a expression in OSCC tissues and cell lines using immunohistochemistry and western blot. The correlation between FOXO3a and stemness was evaluated. Stable cell lines with differential expression of FOXO3a were constructed using lentiviruses. The effects of FOXO3a on stem-cell like properties in OSCC was further evaluated in vitro and in vivo. We also explored the effect of TGFβ on FOXO3a with respect to its expression and function. Our findings suggest that FOXO3a was widely expressed and negatively correlated with the stemness in OSCC. This regulation can be abolished by TGFβ through phosphorylation, nuclear exclusion, and degradation in the non-Smad pathway. We also observed that non-Smad AKT-FOXO3a axis is essential to regulate stemness of CSCs by TGFβ. TGFβ induces stemness through non-canonical AKT-FOXO3a axis in OSCC. Our study provides a foundation to understand the mechanism of CSCs and a possible therapeutic target to eliminate CSCs.

Li K ，Yang L ，Li J ，Guan C ，Zhang S ，Lao X ，Ouyang D ，Zheng G ，Gao S ，Wang D ，Liang Y ，Liao G ... -  《EBioMedicine》

Spindle and kinetochore-associated complex 3 promotes cell growth via the PI3K/AKT/GSK3β and PI3K/AKT/FOXO1 pathways and is a potential prognostic biomarker for oral squamous cell carcinoma.

This study elucidated the clinical significance, functions, and mechanism of action of spindle and kinetochore-associated complex 3 (SKA3) in oral squamous cell carcinoma (OSCC). The SKA3 levels within the patients with OSCC were determined using the The cancer genome atlas (TCGA) database and clinical samples. The functions of SKA3 in OSCC cells were evaluated by cell counting Kit-8 (Beyotime Biotechnology, Haimen, China), 5-ethynyl-2'-deoxyuridine, wound healing, transwell invasion, flow cytometry, and xenograft nude mice model assays. A quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blot were performed to assess mRNA and protein expression levels in specimens and cells, respectively. The SKA3 was highly expressed in OSCC tissues, and its knockdown suppressed OSCC cell proliferation, migration, and invasion, and promoted their apoptosis. Mechanistically, SKA3 was shown to modulate OSCC cell proliferation and apoptosis via the PI3K/AKT/GSK3β and PI3K/AKT/FOXO1 pathways. Biologically, SKA3 has a potential carcinogenic role in OSCC progression and is a promising prognostic biomarker and therapeutic target.

Xu H ，Chen G ，Niu Q ，Song K ，Feng Z ，Han Z ... -  《-》

miR-186-5p inhibits the progression of oral squamous cell carcinoma by targeting ITGA6 to impair the activity of the PI3K/AKT pathway.

microRNAs (miRNAs) are pivotal regulators of multiple biological processes. miR-186-5p functions as a tumor suppressor in a variety of cancers and promotes the malignant proliferation of oral squamous cell carcinoma (OSCC). This study aimed to clarify the role and regulatory mechanism of miR-186-5p in OSCC. The levels of miR-186-5p and integrin subunit alpha 6 (ITGA6) were investigated in clinical specimens and OSCC cell lines by reverse transcription-quantitative polymerase chain reaction. The effects of miR-186-5p and ITGA6 on the cell migration, proliferation, and phosphatidylinositol 3-kinase (PI3K)/serine-threonine kinase (AKT) pathway activity were evaluated by transwell assay, cell counting kit 8 assay, and western blotting, respectively. A xenograft model was used to analyze the effect of miR-186-5p on tumor growth. Bioinformatic analyses were conducted to identify the putative targets of miR-186-5p in OSCC. Decreased miR-186-5p expression levels were observed in OSCC tumor tissues and cell lines. The overexpression of miR-186-5p suppressed the proliferation and migration of OSCC cells, and weakened the phosphorylation of PI3K and AKT. Moreover, the overexpression of miR-186-5p in xenograft tumor models impedes tumor growth. miR-186-5p is bound to ITGA6 and negatively related to ITGA6 expression in tumor tissues. The forced expression of ITGA6 promoted OSCC cell proliferation and migration and enhanced the phosphorylation levels of PI3K and AKT, while additional miR-186-5p enrichment partly abolished these effects. miR-186-5p binds to ITGA6 to impair the activity of the PI3K/AKT signaling pathway, thereby blocking the development of OSCC. This study provides insight to understand the pathogenesis of OSCC.

Chen M ，Zhang J 《-》

BST2 regulated by the transcription factor STAT1 can promote metastasis, invasion and proliferation of oral squamous cell carcinoma via the AKT/ERK1/2 signaling pathway.

Shan F ，Shen S ，Wang X ，Chen G ... -  《-》