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Background/purpose: NF-κB family of transcription factors are the major contributors to malignant tumor progression, maintenance of cancer stemness, and enhancement of chemoresistance. Fenofibrate, a lipid-lowering drug, has been considered as a candidate for repurposing in the treatment of cancer through various pathways involved in apoptosis, cell cycle, migration, and invasion, including NF-κB. Nevertheless, whether fenofibrate possesses the potential to inhibit cancer stemness remained to be examined., Methods: Cytotoxicity of fenofibrate was estimated by MTT assay. The cells expressing stemness marker were detected by flow cytometry using ALDEFLUOR™ Kit. The secondary sphere formation assay was used to assess the self-renewal ability. Transwell system was used to evaluate migration and invasion capacities. NF-κB expression was measured by the immunoblotting system., Results: In the present study, we demonstrated that fenofibrate inhibited cell viability, expression of stemness marker, self-renewal, migration, and invasion capacities in a dose-dependent manner. Of note, fenofibrate targeted cancer stem cells of oral squamous cell carcinoma (OSCC-CSCs) and had minimal effects on normal cells. Moreover, administration of fenofibrate at a lower concentration was sufficient to diminish the expression of NF-κB p50 and p65., Conclusion: This study demonstrated that the inhibitory effects of fenofibrate on OSCC-CSCs properties may be associated with downregulation of NF-κB. These results indicated that administration of fenofibrate may serve as an alternative strategy for OSCC therapy., Competing Interests: Declaration of competing interest The authors have no conflicts of interest relevant to this article., (Copyright © 2022. Published by Elsevier B.V.)

Background/purpose: Various microRNAs (miRs) have been found to be associated with the development of the precancerous condition of the oral cavity, oral submucous fibrosis (OSF). The expression of miR-29c is dysregulated in oral cancer, but its role in OSF has not been investigated. The purpose of the study is to investigate the functional role of miR-29c and its target in OSF., Methods: The expression levels of miR-29c in OSF tissues and fibrotic buccal mucosal fibroblasts (fBMFs) were assessed using next-generation sequencing and real-time Polymerase Chain Reaction (PCR) analysis. MiR-29c mimic and inhibitors were employed to examine its functional role of myofibroblast transdifferentiation. In addition, several myofibroblast phenotypes, such as collagen gel contraction and migration were tested, and a luciferase reporter assay was conducted to confirm the relationship between miR-29c and its predicted target, tropomyosin-1 (TPM1)., Results: We observed that miR-29c expression was downregulated in fBMFs. fBMFs transfected with miR-29c mimics exhibited reduced migration ability and collagen gel contractility, whereas inhibition of miR-29c in normal BMFs induced the myofibroblast phenotypes. Results from the luciferase reporter assay showed that TPM1 was a direct target of miR-29c and the expression of TPM1 was suppressed in the fBMFs transfected with miR-29c mimics. Besides, we confirmed that the expression of miR-29c was indeed downregulated in OSF specimens., Conclusion: MiR-29c seems to exert an inhibitory effect on myofibroblast activation, such as collagen gel contractility and migration ability, via suppressing TPM1. These results suggested that approaches to upregulate miR-29c may be able to ameliorate the progression of OSF., (Copyright © 2021. Published by Elsevier B.V.)

Background/purpose: Betel nut chewing is the major risk factor of oral submucous fibrosis (OSF). Various studies have sought to discover alternative strategies to alleviate oral fibrogenesis. In the present study, we aimed to evaluate the anti-fibrosis effect of paeonol, a phenolic component derived from Paeonia Suffruticosa., Methods: The cytotoxicity of paeonol was tested using normal and fibrotic buccal mucosal fibroblasts (fBMFs) derived from OSF tissues. Collagen gel contraction, Transwell migration, invasion, and wound healing capacities were examined. Besides, the activation of TGF-β/Smad2 signaling and expression levels of type I collagen, α-SMA, and long non-coding RNA HOTAIR were measured as well., Results: Paeonol exerted a higher cytotoxic effect on fBMFs compared to normal BMFs. The arecoline-induced myofibroblast activities, including collagen gel contractility, cell motility, and wound healing ability were all suppressed by paeonol treatment. In addition, the activation of the TGF-β/Smad2 pathway was inhibited along with a lower expression of α-SMA and type I collagen in paeonol-treated cells. Also, the administration of paeonol decreased the mRNA expression of HOTAIR in fBMFs., Conclusion: Our results indicate that paeonol may be a promising compound to attenuate the progression of oral fibrogenesis in OSF patients., Competing Interests: Declaration of competing interest The authors have no conflicts of interest relevant to this article., (Copyright © 2021. Published by Elsevier B.V.)

Periodontitis is a progressive inflammation condition and a primary cause of tooth loss in adults. As one of the abundant cell types in the periodontium, periodontal ligament fibroblasts (PDLFs) play an integral role in the maintenance and regeneration of periodontal tissue. Our previous work has shown that the application of Er:YAG laser increased the cell proliferation and migratory capacity of PDLFs via induction of galectin-7. In the present study, we aimed to evaluate if the forced expression of galectin-7 directly affected the cellular phenotypes of PDLFs. Our results showed that the cell proliferation, transwell migration, invasion, and wound healing capacities were all upregulated in PDLFs with the ectopic expression of galectin-7. These results suggest that therapeutic approaches to enhance the expression of galectin-7 in periodontium may accelerate tissue regeneration by recruiting more PDLFs to the injured site., Competing Interests: Declaration of competing interest The authors have no conflicts of interest relevant to this article., (Copyright © 2021. Published by Elsevier B.V.)

Background/purpose: Emerging evidence suggests the significance of microRNA-155 (miR-155) in fibrogenesis and oxidative stress accumulation, but its function in oral submucous fibrosis (OSF) has not been investigated. In this study, we assessed the expression of miR-155 and its effects on the maintenance of myofibroblast activation., Methods: qRT-PCR was conducted to assess the expression of miR-155 in OSF tissues and fibrotic buccal mucosal fibroblasts (fBMFs) derived from OSF samples. Collagen gel contraction, migration, and invasion capabilities were examined in fBMFs. DCFDA ROS assay was used to examine ROS generation. A luciferase reporter assay was carried out to verify the relationship between miR-155 and its potential target RPTOR., Results: We showed that the expression of miR-155 was aberrantly upregulated in OSF specimens and fBMFs. Inhibition of miR-155 ameliorated various myofibroblast activities, including collagen gel contraction, migration, and invasion abilities as well as ROS production. Results from the luciferase reporter assay demonstrated that miR-155 directly interacted with its target RPTOR., Conclusion: Taken together, these findings indicate that miR-155 is implicated in the pathogenesis of oxidative stress-associated OSF, possibly through the regulation of RPTOR., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2021. Published by Elsevier B.V.)

Background/purpose: Cancer stem cells (CSCs) have been known to be implicated in tumorigenesis, metastasis, and drug resistance in oral squamous cell carcinomas (OSCC). In this study, we aimed to investigate whether magnolol, a polyphenolic component derived from Magnolia officinalis, exhibited the anti-CSCs properties., Methods: The cytotoxicity of magnolol was tested using normal gingival epithelioid SG cells and sphere-forming OSCC-CSCs isolated from SAS, OECM1, and GNM cells. Secondary sphere-forming ability, the proportion of ALDH1 positive cells, Transwell migration, and invasion capacities were examined as well. The chemosensitive effects of magnolol were investigated using MTT, secondary sphere-forming, and invasion assays., Results: Magnolol exerted a higher cytotoxicity of OSCC-CSCs and cancer stemness features, including self-renewal ability, the expression CSC marker, migration, and invasion capacities were all downregulated in magnolol-treated OSCC-CSCs. Moreover, administration of magnolol potentiated the effect of cisplatin, including a decrease in cell viability, self-renewal, and invasion activities. In addition, we observed that the secretion of IL-6 and phosphorylation of Stat3 were decreased in OSCC-CSCs treated with magnolol., Conclusion: Our data suggest that magnolol is able to target CSCs and suppress the cancer stemness properties, at least in part, via IL-6/Stat3 signaling. Besides, a dietary supplement of magnolol may function as an adjunct to cisplatin treatment., Competing Interests: Declaration of competing interest The authors have no conflicts of interest relevant to this article., (Copyright © 2021. Published by Elsevier B.V.)

Background/purpose: The habit of areca nut chewing has been regarded as an etiological factor of precancerous oral submucous fibrosis (OSF). In the present study, we aimed to evaluate the anti-fibrosis effect of honokiol, a polyphenolic component derived from Magnolia officinalis., Methods: The cytotoxicity of honokiol was tested using normal and fibrotic buccal mucosal fibroblasts (fBMFs) derived from OSF tissues. Collagen gel contraction, Transwell migration, invasion, and wound healing capacities were examined. Besides, the expression of TGF-β/Smad2 signaling as well as α-SMA and type I collagen were measured as well., Results: Honokiol exerted higher cytotoxicity of fBMFs compared to normal cells. The arecoline-induced myofibroblast activities, including collagen gel contractility, cell motility and wound healing capacities were all suppressed by honokiol treatment. In addition, the expression of the TGF-β/Smad2 pathway was downregulated along with a lower expression of α-SMA and type I collagen in honokiol-receiving cells., Conclusion: Our data suggest that honokiol may be a promising compound to alleviate the progression of oral fibrogenesis and prevent the transformation of OSF oral epithelium into cancer., Competing Interests: Declaration of competing interest The authors have no conflicts of interest relevant to this article., (Copyright © 2021. Published by Elsevier B.V.)

Background/purpose: Oral submucous fibrosis (OSF) a well-recognized oral premalignant disorder. Several studies have demonstrated that periostin, a matricellular protein, is involved in the development and pathogenesis of fibrosis diseases. Nevertheless, the contribution of periostin in OSF remains to be uncovered. The purpose of the study was to illustrate the functional role of periostin involved in OSF pathogenesis., Methods: RNA-sequencing was employed to screen for differentially expressed genes in normal and OSF tissues. Validation of the upregulation of periostin in OSF specimens and fibrotic buccal mucosal fibroblasts (fBMFs) was conducted by qRT-PCR. The correlation of the gene expression of periostin and various fibrosis markers was analyzed. In addition, the functional role of periostin in myofibroblast features was tested using collagen gel contraction and transwell migration assays., Results: We observed overexpression of periostin in OSF specimens using RNA-sequencing and confirmed its upregulation in OSF tissues and patient-derived fBMFs. Besides, there was a positive relationship between the expression of periostin and several fibrosis-associated markers, including ACTA2 (α-smooth muscle actin; α-SMA), COL1A1 (type 1 collagen α1 chain), TGFB1 (TGF-β1), and FN1 (fibronectin). Furthermore, we examined the effect of silencing periostin on the maintenance of myofibroblast characteristics and showed that knockdown of periostin suppressed the expression of α-SMA. Also, inhibition of periostin markedly downregulated the myofibroblast activities (collagen gel contraction and migration capacities)., Conclusion: Our results indicate the aberrant expression of periostin in OSF tissues and myofibroblasts. Moreover, the expression of periostin is positively associated with fibrosis markers, and repression of periostin may be a promising direction to alleviate the progression of OSF., Competing Interests: Declaration of competing interest The authors have no conflicts of interest relevant to this article., (Copyright © 2021. Published by Elsevier B.V.)

Background/purpose: Periodontal disease and diabetes mellitus (DM) are both chronic inflammatory and highly prevalent diseases. A large amount of evidence suggested that the accumulation of oxidative stress plays a significant role in the deterioration of both diseases. Magnolol has been known to possess anti-inflammatory and anti-oxidant activities in various tissues, but its effects on gingival cells under diabetic conditions have not been fully understood., Methods: We assessed the generation of reactive oxygen species (ROS), Transwell migration, and wound healing ability in response to the advanced glycation end products (AGEs) stimulation with or without Magnolol treatment. Subsequently, we examined the expression of Nrf2 and HO-1 to ascertain whether Magnolol was able to activate the anti-oxidant signaling. We also measured the secretion of IL-6 and IL-8, and conducted a knockdown experiment to elucidate the effect of Mrf2 on their secretion., Results: The AGEs-induced ROS was dose-dependently downregulated following the Magnolol treatment. Likewise, the reduced Transwell migration and wound healing ability were improved by various concentrations of Magnolol. Results from qRT-PCR indicated that the suppression of Nrf2 and HO-1 following AGEs stimulation was reversed by Magnolol. Also, the AGEs-elicited production of IL-6 and IL-8 was inhibited by Magnolol. Moreover, our results demonstrated that this anti-inflammatory effect was mediated by the upregulation of Nrf2., Conclusion: These findings showed that excessive AGEs in the gingiva may lead to the accumulation of ROS and pro-inflammatory cytokines. Supplement of Magnolol may be beneficial to improve the impaired wound healing and inflammation by upregulation of Nrf2 signaling for DM patients with periodontal disease., Competing Interests: Declaration of competing interest The authors have no conflicts of interest relevant to this article., (Copyright © 2021. Published by Elsevier B.V.)

Background/purpose: Long non-coding RNA HOXA transcript at the distal tip (HOTTIP) has been reported to contribute to multiple carcinomas, but whether it involves in the progression of precancerous conditions remains to be determined. Oral submucous fibrosis (OSF) has been known as an oral potentially malignant disorder and attributed to the persistent activation of the myofibroblast., Methods: The relative expression of HOTTIP in OSF tissues has been employed by RNA-sequencing and RT-PCR analysis. HOTTIP associated myofibroblasts activities and markers in fibrotic buccal mucosal fibroblast (fBMFs) through loss of function approaches have been evaluated., Results: In the present study, we found that the expression of HOTTIP was overexpressed in the OSF tissues and positively correlated with several fibrosis markers. To investigate its significance of myofibroblast activation, we first verified the expression level of HOTTIP in the patient-derived fibrotic buccal mucosal fibroblast (fBMFs) was upregulated and conducted the shRNA-mediated knockdown experiment to inhibit its expression followed by numerous examinations. We demonstrated that suppression of HOTTIP downregulated the expression of myofibroblast marker, α-SMA, and type I collagen along with the diminished myofibroblast activities (collagen gel contraction and migration capacities). Furthermore, we showed that silencing HOTTIP lessened the production of various pro-inflammatory cytokines (IL-6 and TNF-α)., Conclusion: Collectively, our results suggest that HOTTIP plays a crucial role in the persistent activation of myofibroblasts as well as the chronic inflammation and collagen deposition., Competing Interests: Declaration of Competing Interest The authors have no conflicts of interest relevant to this article., (Copyright © 2021. Published by Elsevier B.V.)

Background/purpose: Oral submucous fibrosis (OSF) is an irreversible fibrosis disease and a potentially malignant disorder in the oral cavity. Various studies have shown that miR-21 was implicated in the fibrogenesis and carcinogenesis, but its functional role in the development of OSF has not been investigated., Methods: The expression levels of miR-21 in arecoline-stimulated normal buccal mucosal fibroblasts (BMFs) and OSF specimens were determined by qRT-PCR. Exogenous administration of TGF-β and its inhibitor (SB431542) were utilized to examine the involvement of TGF-β signaling in miR-21 alteration. Collagen gel contraction, transwell migration, and invasion assays were used to assess the myofibroblast activities. The relationship between α-SMA and miR-21 was calculated using the Pearson correlation coefficient., Results: MiR-21 expression was induced in BMFs by arecoline treatment in a dose-dependent manner. Our results showed that this upregulation was mediated by TGF-β signaling. Subsequently, we demonstrated that the administration of the miR-21 inhibitor suppressed the arecoline-induced myofibroblast characteristics, including a higher collagen gel contractility and cell motility, in normal BMFs. Furthermore, inhibition of miR-21 was sufficient to attenuate the myofibroblast features in fibrotic BMFs. Besides, we showed that the expression of miR-21 was aberrantly upregulated in the OSF tissues and there was a positive correlation between miR-21 and myofibroblast marker, α-SMA., Conclusion: MiR-21 overexpression in OSF may be due to the stimulation of areca nut, which was mediated by the TGF-β pathway. Our data suggested that the repression of miR-21 was a promising direction to palliate the development and progression of OSF., Competing Interests: Declaration of competing interest The authors have no conflicts of interest relevant to this article., (Copyright © 2020. Published by Elsevier B.V.)

Background/purpose: Oral cancer stem cells (CSCs) have been considered as the key cells that are implicated in tumor recurrence and metastasis. In recent years, great attention has been paid to the significance of various non-coding RNAs due to their regulatory roles in oral CSCs. Although the function of long non-coding RNA MEG3 in various cancers has been investigated, its effects on the features of oral CSCs remained to be determined., Methods: The expression levels of MEG3 in tongue squamous cell carcinomas and prognostic effect have been evaluated. We assessed the expression of MEG3 in sphere cells (oral CSCs) using qRT-PCR. Secondary sphere formation and invasion assays were conducted to evaluate the self-renewal and metastatic abilities, respectively. Bioinformatics software and luciferase reporter assay were used to predict and verify the relationship between MEG3 and miR-421., Results: MEG3 was downregulated in the tissues of oral cancer and associated with a poor prognosis. In oral CSCs, the expression of MEG3 was repressed and overexpression of MEG3 resulted in suppression of self-renewal and invasion abilities. Luciferase reporter assay showed that miR-421 directly interacted with MEG3, and our subsequent experiment demonstrated that elevation of miR-421 reversed the MEG3-inhibited characteristics of oral CSCs., Conclusion: Our findings suggest that MEG3 can serve as a tumor suppressor in oral CSCs by impeding the action of miR-421. Moreover, targeting MEG3-miR-421 axis has the potential to mitigate the tumor recurrence and metastasis., Competing Interests: Declaration of competing interest The authors have no conflicts of interest relevant to this article., (Copyright © 2020. Published by Elsevier B.V.)

Background/purpose: Among various dental lasers, the erbium-doped yttrium-aluminum-garnet (Er:YAG) laser has great potential for periodontal treatment including soft and hard tissue ablation with minimal thermal side effects under suitable energy densities and it has multiple effects on tissues for wound-healing benefits. In the present study, we sought to reveal the molecular mechanism underlying the impact of Er:YAG laser on PDL fibroblasts., Methods: Cells were irradiated by a Er:YAG laser with various energy densities (3.6-6.3 J/cm 2 ). MTT assay was used for cell proliferation, and the transwell system was employed for migration and invasion abilities. The wound healing capacity was evaluated by a scratch assay. After confirming these effects, qRT-PCR and western blotting analysis was applied to identify the differentially galectin-7 expression in the irradiated cells. Knockdown experiments were conducted to reveal the functional role of galectin-7 in the modulation of Er:YAG laser-mediated effects., Results: 4.2 J/cm 2 was the lowest energy density to induce the optimal cell proliferation, migration and invasion abilities. In the group of upregulated genes, galectin-7 was selected for further examination and its elevation after Er:YAG laser treatment was validated by RT-PCR and Western blot. We demonstrated that silence of galectin-7 abrogated the effects of Er:YAG laser on cell proliferation, migration ad invasion, suggesting the Er:YAG laser promoted these effects through induction of galectin-7., Conclusion: These findings indicated that Er:YAG laser may accelerate the regeneration process in periodontal tissues through enhancement of their proliferative and mobile activities. Additionally, the significance of galectin-7 in the Er:YAG laser-elicited benefits was demonstrated., Competing Interests: Declaration of Competing Interest The authors have no conflicts of interest relevant to this article., (Copyright © 2020. Published by Elsevier B.V.)

Background/purpose: Oral cancer is amongst the most prevalent cancers worldwide with rising incidence. Various attempts have been made to elucidate its pathogenesis, and we sought to examine the function of a ubiquitin E3 ligase that was encoded by STUB1., Methods: The mRNA expression of STUB1 in oral cancer samples and normal counterparts was determined by qRT-PCR. Numerous assays to assess the features of cancer cells, including self-renewal capacity, invasion and migration abilities were conducted following knockdown or overexpression of STUB1., Results: The expression level of STUB1 was reduced in oral cancer, which was associated with a reduced relapse-free survival. Two oral cancer cell lines with low expression of STUB1 (SAS and HSC3) were chosen for the overexpression of STUB1. We showed that ectopic expression of STUB1 led to the downregulation of TGM2, a multifunctional protein that contributed to cancer progression in several cancers. Our results demonstrated that overexpression of STUB1 suppressed the cancer aggressiveness, while restoration of TGM2 reverted the effects. Last, we showed that STUB1 silencing resulted in enhanced cancer features., Conclusion: The abnormal downregulation of STUB1 may lessen its suppressive effect on TGM2, which induced the onset or exacerbated the progression of oral cancer. The therapeutic approach to enhance the expression of STUB1 could be a promising direction for cancer therapy., Competing Interests: Declaration of Competing Interest The authors have no conflicts of interest relevant to this article., (Copyright © 2020. Published by Elsevier B.V.)

Background/purpose: Gingival overgrowth can occur as a result of poor oral hygiene or a side effect of taking certain medications, such as cyclosporine A (CsA). It has been shown that this immunosuppressant drug induces epithelial-to-mesenchymal transition (EMT) in the gingival epithelium but the associated molecular mechanism remains to be elucidated., Methods: We first assessed the relative expression of microRNA-200a (miR-200a) in response to the CsA treatment using qRT-PCR. Next, luciferase reporter assay was applied to examine whether miR-200a was able to regulate ZEB2 and Western blot was utilized to measure the expression of ZEB2 in normal human gingival fibroblasts (HGFs). To confirm the significance of miR-200a and ZEB2 in the CsA-induced gingival overgrowth, miR-200a inhibitor and shRNA mediated knockdown of ZEB2 were used and cell proliferation in HGFs was assessed by MTT assay., Results: The expression of miR-200a was dose-dependently downregulated following the CsA treatment. Luciferase reporter assay confirmed that ZEB2 was a direct downstream target regulated by miR-200a and ZEB2 was indeed increased after the administration of CsA. We demonstrated that knockdown of ZEB2 hampered the CsA-induced HGFs proliferation and the elevated cell proliferation due to inhibition of miR-200a was reversed by repression of ZEB2., Conclusion: Our results showed that insufficient miR-200a in HGFs caused by CsA administration may lead to gingival enlargement mediated by the upregulation of ZEB2. This finding supported that CsA-induced EMT contributed to the adverse effect of using CsA and miR-200a may serve as an upstream target to prevent the overgrowth of the gingiva., Competing Interests: Declaration of Competing Interest The authors have no conflicts of interest relevant to this article., (Copyright © 2020. Published by Elsevier B.V.)

Background/purpose: Oral submucous fibrosis (OSF) is an oral precancerous disorder associated with the habit of areca nut chewing. MiR-10b has been shown to be upregulated in the oral cancer cells and induced by Twist. Our previous work has revealed that Twist participated in the pathogenesis of OSF and therefore we aimed to investigate whether Twist/miR-10b axis was involved in the activation of myofibroblast in the oral cavity., Methods: The expression levels of miR-10b in OSF tissues and fibrotic buccal mucosal fibroblasts (fBMFs) were examined. Besides, the expression of miR-10b was determined in fBMFs following knockdown of Twist or in BMFs after arecoline stimulation. Myofibroblast activities, including collagen gel contraction, migration and wound healing abilities, as well as the expression of α-SMA were measured in fBMFs treated with miR-10b inhibitor. Last, we investigated whether the effect of Twist overexpression could be reversed by suppression of miR-10b., Results: MiR-10b expression was overexpressed in both OSF tissues and fBMFs. The silence of Twist resulted in the downregulation of miR-10b in fBMFs and arecoline treatment led to an increase of miR-10b in a dose-dependent manner. Inhibition of miR-10b ameliorated the activation of myofibroblasts and the expression of α-SMA. Moreover, we demonstrated that suppression of miR-10b hindered the increased collagen gel contraction caused by Twist overexpression., Conclusion: MiR-10b upregulation in OSF may be due to the stimulation of areca nut, leading to elevated myofibroblast activation. Our findings showed that the areca nut-induced expression of miR-10b was under the regulation of Twist and inhibition of miR-10b may provide a direction for treatment of OSF., Competing Interests: Declaration of competing interest The authors have no conflicts of interest relevant to this article., (Copyright © 2020. Published by Elsevier B.V.)

Background/purpose: Oral submucous fibrosis (OSF) represents a precancerous lesion of oral mucosa that may progress into oral cancer and its major etiological factor is areca nut chewing. Carboxyl-terminus of Hsp70-interacting protein (CHIP) functions as an ubiquitin E3 ligase and is associated with fibrosis diseases. In the current study, we sought to investigate whether CHIP participated in the areca nut-mediated OSF development., Methods: The mRNA expression of CHIP in arecoline-stimulated buccal mucosal fibroblasts (BMFs) and OSF tissues was determined by qRT-PCR. Collagen gel contraction, migration and invasion assays were carried out to evaluate the myofibroblast activation. The protein expression levels of α-SMA and transglutaminase 2 (TGM2) were assessed by Western blot., Results: The expression level of CHIP was reduced in BMFs following arecoline treatment in a dose-dependent manner, which was consistent with the observation of lower CHIP expression in OSF specimen compared to the normal counterparts. Ectopic expression of CHIP mitigated the myofibroblast activities, including elevated collagen gel contractility and cell motility. In addition, we showed that overexpression of CHIP downregulated the α-SMA and TGM-2 expression, which may lead to less fibrosis alteration., Conclusion: CHIP may not only function as a key regulator of protein quality control but also a critical deciding factor to oral fibrogenesis. Our findings suggested that CHIP possesses the anti-fibrotic effect, which may be mediated by TGM2 regulation. Restoration of CHIP could be a therapeutic direction to help OSF patients., Competing Interests: Declaration of competing interest None declared., (Copyright © 2019. Published by Elsevier B.V.)

Background/purpose: Oral submucous fibrosis (OSF) is a precancerous condition of oral cancer with a complex etiology. Our previous work has demonstrated that non-coding RNA miR-1246 contributes to the cancer stemness of oral cancer. In the current study, we sought to investigate the effect of the inhibition of miR-1246 on the oral fibrogenesis., Methods: The expression levels of miR-1246 in OSF tissues and fibrotic buccal mucosal fibroblasts (fBMFs) were examined by qRT-PCR. Collagen gel contraction and migration assays were conducted to evaluate the myofibroblast activities. The relationship between miR-1246 and type I collagen was assessed and the protein expression of type I collagen was determined by Western blot., Results: MiR-1246 expression was upregulated in both OSF specimen and fBMFs compared to the normal counterparts. Inhibition of miR-1246 successfully suppressed the myofibroblast activities, including collagen gel contractility and migration capacity. Moreover, the expression of miR-1246 was positively correlated with type I collagen and the expression of type I collagen was abrogated by repression of miR-1246., Conclusion: MiR-1246 is not only critical to the maintenance of oral stemness but also important to the activation of myofibroblasts. Our results showed that miR-1246 is positively associated with the type I collagen, which may be a downstream effector of miR-1246 and responsible for the fibrosis effect on fBMFs., (Copyright © 2019. Published by Elsevier B.V.)

Background/purpose: Cyclosporine A (CsA) has been used as an immunosuppressive agent with a side effect of gingival overgrowth. It has been known that CsA-induced epithelial-mesenchymal transition (EMT) in gingiva, but the molecular mechanism has not been fully unveiled. The purpose of the study is to investigate functional roles of microRNAs in gingival overgrowth., Methods: The effect of CsA on the expression of microRNA-200b (miR-200b) in normal human gingival fibroblasts (HGFs) was determined using qRT-PCR. Luciferase reporter assay and Western blot were utilized to examine the relationship between miR-200b and EMT inducer Slug. Cell proliferation was assessed by MTT assay., Results: CsA was found to downregulate the miR-200b transcript in HGFs in a dose-dependent manner. Luciferase reporter assay confirmed that Slug was a direct target of miR-200b, and the CsA-induced cell proliferation and Slug upregulation were inhibited by overexpression of miR-200b. Additionally, the silence of Slug reversed the increased proliferation of HGFs by miR-200b inhibitor., Conclusion: Repression of miR-200b after CsA administration led to an increase in Slug expression. Our results suggested that miR-200b was an upstream effector of the CsA-induced EMT and may act as a therapeutic target for CsA-induced gingival overgrowth., (Copyright © 2018. Published by Elsevier B.V.)

Background/purpose: MicroRNA-200c (miR-200c) recently emerged as an important regulator of tumorigenesis and cancer metastasis, however, its role in regulating oral submucous fibrosis (OSF) remains unknown. In this study, we investigated the functional role of miR-200c in myofibroblastic differentiation activity and identified its potential target., Methods: qRT-PCR was applied to assess the expression of miR-200c in OSF tissues and fibrotic buccal mucosal fibroblasts (fBMFs). Arecoline, a major areca nut alkaloid, was utilized to explore whether the expression of miR-200c would alter following stimulation. Collagen gel contraction, migration and invasion capabilities were examined in arecoline-stimulated BMFs as wells as in fBMFs. Luciferase reporter assay was conducted to show the relationship between miR-200c and ZEB1., Results: Our results showed that the expression of miR-200c was downregulated in OSF specimen and fBMFs. Arecoline treatment dose-dependently reduced the relative expression of miR-200c in normal BMFs. Overexpression of miR-200c impeded the arecoline-induced collagen gel contraction, migration, invasion and wound healing capacities. Moreover, ectopic expression of miR-200c in fBMFs successfully reduced the increased collagen gel contractility and invasion abilities. Our results demonstrated that ZEB1 was a direct target of miR-200c, and overexpression of miR-200c inhibited the expression of ZEB1 and α-SMA., Conclusion: These findings suggest that downregulation of miR-200c in OSF may be involved in the pathogenesis of areca nut-associated OSF through regulation of ZEB1., (Copyright © 2018. Published by Elsevier B.V.)

Background/purpose: Emerging research findings suggest that long non-coding RNAs (lncRNAs) are key regulators to fibrosis formation. Nevertheless, the role of lncRNA GAS5-AS1 in the progression of precancerous oral submucous fibrosis (OSF) remains to be elucidated., Methods: Quantitative real-time PCR were used to examine the expression of GAS5-AS1 in OSF tissues. The activities of myofibroblasts, including collagen contractility and cell migration, as well as the marker α-smooth muscle actin (SMA) were assessed following overexpression of GAS5-AS1. Also, we analyzed the expression of Smad activity in order to gain insight into the downstream regulator., Results: The level of GAS5-AS1 was found significantly downregulated in the OSF tissues and fibrotic buccal mucosal fibroblasts (fBMFs). Ectopic expression of GAS5-AS1 significantly reduced the abilities of collagen gel contraction and migration in fBMFs or arecoline-treated BMFs. Moreover, we have shown that overexpression of GAS5-AS1 inhibited the expression of p-Smad and the marker of myofibroblasts., Conclusion: We showed the reduced expression of GAS5-AS1 in OSF tissues and demonstrated its effect on the myofibroblast activities and the level of p-Smad and α-SMA, indicating its potential contribution in OSF pathogenesis., (Copyright © 2017. Published by Elsevier B.V.)

Background/purpose: Cumulative evidence suggest that microRNAs (miRNAs) function as biosignatures of oral squamous cell carcinomas (OSCC). However, the functional roles of miR-1 as well as its downstream targets in the regulation of tumorigenicity in OSCC remain unclear., Methods: miRNAs RT-PCR analysis was performed to identify miR-1 as a putative candidate on mediating invasiveness of OSCC cells. Consequently, we elucidated the tumorigenicity of OSCC cells with miR-1 downregulation or overexpression, respectively. Finally, miR-1 on OSCC tumor tissues was examined., Results: miR-1 levels were significantly downregulated in the malignant OSCC cells. Overexpression of miR-1 significantly reduced migration/invasiveness of OSCC cells. In addition, overexpression of miR-1 decreased cancer stem cells properties. Conversely, downregulation of miR-1 promotes migration and invasiveness in OSCC cells. We have shown that miR-1 is able to target Slug, suppressing their expression. Clinically, lower miR-1 expression was found in patients with advanced nodal metastasis OSCC., Conclusion: miR-1 as novel biosignatures in OSCC lymph node metastatic patients, supporting the development of novel strategies for OSCC treatment., (Copyright © 2017. Published by Elsevier B.V.)

Background/purpose: Cancer stem cells (CSCs) are deemed as the driving force of tumorigenesis in oral squamous cell carcinomas (OSCCs). In this study, we investigated the chemotherapeutic effect of sulforaphane, a dietary component from broccoli sprouts, on targeting OSCC-CSCs., Methods: The effect of sulforaphane on normal oral epithelial cells (SG) and sphere-forming OSCC-CSCs isolated from SAS and GNM cells was examined. ALDH1 activity and CD44 positivity of OSCC-CSCs with sulforaphane treatment was assessed by flow cytometry analysis. In vitro and in vivo tumorigenicity assays of OSCC-CSCs with sulforaphane treatment were presented., Results: We observed that the sulforaphane dose-dependently eliminated the proliferation rate of OSCC-CSCs, whereas the inhibition on SG cells proliferation was limited. Cancer stemness properties including self-renewal, CD44 positivity, and ALDH1 activity were also decreased in OSCC-CSCs with different doses of sulforaphane treatment. Moreover, sulforaphane treatment of OSCC-CSCs decreased the migration, invasion, clonogenicity, and in vivo tumorigenicity of xenograghts. Sulforaphane treatment resulted in a dose-dependent increase in the levels of tumor suppressive miR200c., Conclusion: These lines of evidence suggest that sulforaphane can suppress the cancer stemness and tumor-initiating properties in OSCC-CSCs both in vitro and in vivo., (Copyright © 2016. Published by Elsevier B.V.)