Paeonol inhibits profibrotic signaling and HOTAIR expression in fibrotic buccal mucosal fibroblasts

Hypoxia amplifies arecoline-induced invasion and metastasis in oral squamous cell carcinoma - Insights into TGF-β1 signaling and collagen production

Background/Purpose

Betel quid chewing is a major risk factor for oral squamous cell carcinoma (OSCC), largely due to arecoline, a key alkaloid. Hypoxia, common in the tumor microenvironment, also influences cancer progression. This study investigated the combined effects of arecoline and hypoxia on proliferation, migration, and protein expression in tongue squamous cell carcinoma (SCC-25) cells, focusing on the TGF-β1 signaling pathway and type I collagen production.

Materials and methods

SCC-25 cells were treated with arecoline and incubated for 24 h under normoxia or hypoxia. Cytotoxicity assays and Western blotting were performed to assess cell viability and protein expression.

Results

At 2.5 μg/mL, arecoline enhanced SCC-25 cell proliferation under normoxia, while hypoxia suppressed this effect. Arecoline significantly promoted cell migration that was further amplified by hypoxia. Western blotting revealed that arecoline upregulated TGF-β1, Smad2/3, phosphorylated Smad2/3, and type I collagen. Under hypoxia, HIF1-α expression increased along with TGF-β1 and type I collagen, indicating that hypoxia enhances arecoline-induced collagen production through TGF-β1 signaling.

Conclusion

Arecoline stimulates SCC-25 cell proliferation and migration, with hypoxia amplifying these effects by promoting TGF-β1 signaling and type I collagen production. These findings suggest that betel quid consumption, in combination with hypoxia, may exacerbate the invasion and metastasis of OSCC.

Impact of red-lime and white-lime betel quid on oral cell lines: Cytotoxicity and effects on fibronectin and type I collagen expression

Background/purpose

Chewing betel quid is linked to an increased risk of oral cancer. This study investigates the effects of red-lime and white-lime betel quid extracts on oral cell lines, focusing on cytotoxicity and their influence on fibronectin and Type I collagen expression, which were crucial for oral tissue integrity and cancer development.

Materials and methods

Four oral cell lines, human gingival fibroblasts, tongue squamous cell carcinoma cells, human periodontal ligament fibroblasts, and human fetal osteoblasts, were treated with red-lime and white-lime betel quid extracts. Cytotoxicity assays and Western blotting were used to assess cell viability and protein expression.

Results

Both red-lime and white-lime betel quid extracts exhibited dose-dependent effects on all tested cell lines, with variations in sensitivity observed among cell types. Notably, red-lime betel quid exerted stronger cytotoxic effects on human gingival fibroblasts and human fetal osteoblasts. Red-lime betel quid increased fibronectin and Type I collagen in periodontal ligament fibroblasts but reduced both proteins in fetal osteoblasts. White-lime betel quid extract generally elevated fibronectin and decreased Type I collagen across cell lines.

Conclusion

This study reveals a nuanced, concentration-dependent impact of betel quid extracts on oral cells, with significant variability in cytotoxicity and changes in fibronectin and Type I collagen expression. These findings suggest that abrupt cessation of betel quid chewing can lead to dental issues such as mobile teeth. Red-lime betel quid uniquely affects periodontal ligament fibroblasts by increasing both fibronectin and Type I collagen.

Resveratrol inhibits arecoline-induced fibrotic properties of buccal mucosal fibroblasts via miR-200a activation

Background/purpose

Oral submucous fibrosis (OSF) is a precancerous lesion in the oral cavity, commonly results from the Areca nut chewing habit. Arecoline, the main component of Areca nut, is known to stimulate the activation of myofibroblasts, which can lead to abnormal collagen I deposition. Meanwhile, Resveratrol is a non-flavonoid phenolic substance that can be naturally obtained from various berries and foods. Given that resveratrol has significant anti-fibrosis traits in other organs, but little is known about its effect on OSF, this study aimed to investigate the therapeutic impact of resveratrol on OSF and its underlying mechanism.

Materials and methods

The cytotoxicity of resveratrol was tested using normal buccal mucosal fibroblasts (BMFs). Myofibroblast phenotypes such as collagen contractile, enhanced migration, and wound healing capacities in dose-dependently resveratrol-treated fBMFs were examined.

Results

Current results showed that arecoline induced cell migration and contractile activity in BMFs as well as upregulated the expressions of α-SMA, type I collagen, and ZEB1 markers. Resveratrol intervention, on the other hand, was shown to inhibit arecoline-induced myofibroblast activation and reduce myofibroblast hallmarks and EMT markers. Additionally, resveratrol was also demonstrated to restore the downregulated miR-200a in the arecoline-stimulated cells.

Conclusion

In a nutshell, these findings implicate that resveratrol may have an inhibitory influence on arecoline-induced fibrosis via the regulation of miR-200a. Hence, resveratrol may be used as a therapeutic strategy for OSF intervention.

Downregulation of histone deacetylase 8 (HDAC8) alleviated the progression of oral submucous fibrosis

Background/purpose

Oral submucous fibrosis (OSF) is a premalignant disorder that is associated with betel nut chewing. The purpose of the study was to establish the role of histone deacetylase (HDAC) 8, one of histone deacetylases, in the regulation of fibrotic conditions to provide a therapeutic potential for OSF.

Materials and methods

First, we examined the expression of HDAC8 in fibrotic buccal mucosal fibroblasts (fBMFs) and OSF tissues. Markers of myofibroblasts and TGF-β signaling were conducted in fBMFs with HDAC8 knockdown were examined. Furthermore, epithelial-mesenchymal transition (EMT) markers, collagen gel contraction and migration ability were also examined in fBMFs transfected with sh-HDAC8. HDAC8 inhibitor was used to analyze the collagen gel contraction and wound healing ability in fBMFs.

Results

We observed the mRNA expression of HDAC8 was significantly increased in fBMFs. Compared to normal tissues, the protein level of HDAC8 was upregulated in OSF. Next, mRNA and protein expression of HDAC8 was significantly decreased, accompanying downregulation of α-SMA and COL1A1 in fBMFs infected with sh-HDAC8. To determine the critical role of HDAC8 in OSF fibrogenesis, results revealed that TGF-β secretion and the expression of EMT transcription factor SNAIL and p-Smad were significantly decreased in HDAC8-knockdown fBMFs. We further demonstrated that collagen gel contraction and migration ability were significantly decreased in fBMFs transfected with sh-HDAC8. Last, results revealed that significantly reduced collagen gel contraction and wound healing ability in fBMFs with HDAC8 inhibitor treatment.

Conclusion

We concluded that downregulation of HDAC8 alleviated the activities of myofibroblasts and TGF-β/Smad signaling pathway in OSF.