MiRNAs have been recognized as crucial components in carcinogenesis, but whether miR-1246 affects the cancer stemness and drug resistance in oral squamous cell carcinoma (OSCC) has not been fully understood and its downstream targets still need to be unraveled. In the present work, we employed miRNAs RT-PCR analysis to evaluate the expression of miR-1246 in tumor tissues and oral cancer stem cells (OCSC). Stemness phenotypes, including self-renewal, migration, invasion, colony formation capacities, and in vivo oncogenicity of oral cancer cells following transfected with miR-1246 inhibitors or mimics were examined. Our results suggested that the expression level of miR-1246 was significantly upregulated in the tumor tissues and OCSC. Kaplan-Meier survival analysis of OSCC patients with high levels of miR-1246 had the worst survival rate compared to their low-expression counterparts. Inhibition of miR-1246 in OCSC significantly reduced the stemness hallmarks, while overexpression of miR-1246 enhanced these characteristics. Moreover, we showed that downregulation of miR-1246 decreased chemoresistance. In addition, we verified that miR-1246-inhibited CCNG2 contributed to the cancer stemness of OSCC. These results demonstrated the significance of miR-1246 in the regulation of OSCC stemness. Targeting miR-1246-CCNG2 axis may be beneficial to suppress cancer relapse and metastasis in OSCC patients.

Current evidence suggests that oral cancer stem cells (OCSCs) possess high tumorigenic and metastatic properties as well as chemo- and radioresistance. In this study, we demonstrated that andrographolide, the main bioactive component in the medicinal plant Andrographis, significantly reduced oncogenicity and restored radio-sensitivity of ALDH1+CD44+ OCSCs. Mechanistic studies showed that andrographolide treatment increased the expression of microRNA-218 (miR-218), leading to the downregulation of Bmi1. We showed that knockdown of miR-218 in ALDH1−CD44− non-OCSCs enhanced cancer stemness, while silencing of Bmi1 significantly counteracted it. Furthermore, we found tumor growth was reduced in mice bearing xenograft tumors after andrographolide treatment via activation of miR-218/Bmi1 axis. Together, these data demonstrated that the inhibition of tumor aggressiveness in OCSCs by andrographolide was mediated through the upregulation of miR-218, thereby reducing Bmi1 expression. These findings suggest that andrographolide may be a valuable natural compound for anti-CSCs treatment of OSCC.

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.

Oral submucous fibrosis (OSF) is known as a potentially malignant disorder, which may result from chemical irritation due to areca nuts (such as arecoline). Emerging evidence suggests that fibrogenesis and carcinogenesis are regulated by the interaction of long noncoding RNAs (lncRNAs) and microRNAs. Among these regulators, profibrotic lncRNA H19 has been found to be overexpressed in several fibrosis diseases. Here, we examined the expression of H19 in OSF specimens and its functional role in fibrotic buccal mucosal fibroblasts (fBMFs). Our results indicate that the aberrantly overexpressed H19 contributed to higher myofibroblast activities, such as collagen gel contractility and migration ability. We also demonstrated that H19 interacted with miR-29b, which suppressed the direct binding of miR-29b to the 3′-untranslated region of type I collagen (COL1A1). We showed that ectopic expression of miR-29b ameliorated various myofibroblast phenotypes and the expression of α-smooth muscle actin (α-SMA), COL1A1, and fibronectin (FN1) in fBMFs. In OSF tissues, we found that the expression of miR-29b was downregulated and there was a negative correlation between miR-29b and these fibrosis markers. Lastly, we demonstrate that arecoline stimulated the upregulation of H19 through the transforming growth factor (TGF)-β pathway. Altogether, this study suggests that increased TGF-β secretion following areca nut chewing may induce the upregulation of H19, which serves as a natural sponge for miR-29b and impedes its antifibrotic effects.

Cancer stem cells (CSCs) are cells that drive tumorigenesis, contributing to metastasis and cancer recurrence as well as resistance to chemotherapy of oral squamous cell carcinomas (OSCC). Therefore, approaches to target CSCs become the subject of intense research for cancer therapy. In this study, we demonstrated that isoliquiritigenin, a chalcone-type flavonoid isolated from licorice root, exhibited more toxicity in oral cancer stem cells (OSCC-CSCs) compared to normal cells. Treatment of isoliquiritigenin not only inhibited the self-renewal ability but also reduced the expression of CSC markers, including the ALDH1 and CD44. In addition, the capacities of OSCC-CSCs to invade, metastasize and grow into a colony were suppressed by isoliquiritigenin. Most importantly, we showed that isoliquiritigenin potentiated chemotherapy along with downregulated expression of an ABC transporter that is associated with drug resistance, ABCG2. Moreover, a combination of isoliquiritigenin and Cisplatin significantly repressed the invasion and colony formation abilities of OSCC-CSCs. Our results suggested that administration of isoliquiritigenin reduced the protein expression of mRNA and membrane GRP78, a critical mediator of tumor biology. Overexpression of GRP78 reversed the inhibitory effect of isoliquiritigenin on OSCC-CSCs. Furthermore, isoliquiritigenin retarded the tumor growth in nude mice bearing OSCC xenografts. Taken together, these findings showed that isoliquiritigenin is an effective natural compound that can serve as an adjunct to chemotherapy for OSCC.

BackgroundHigh tidal volume (VT) mechanical ventilation (MV) can induce the recruitment of neutrophils, release of inflammatory cytokines and free radicals, and disruption of alveolar epithelial and endothelial barriers. It is proposed to be the triggering factor that initiates ventilator-induced lung injury (VILI) and concomitant hyperoxia further aggravates the progression of VILI. The Src protein tyrosine kinase (PTK) family is one of the most critical families to intracellular signal transduction related to acute inflammatory responses. The anti-inflammatory abilities of induced pluripotent stem cells (iPSCs) have been shown to improve acute lung injuries (ALIs); however, the mechanisms regulating the interactions between MV, hyperoxia, and iPSCs have not been fully elucidated. In this study, we hypothesize that Src PTK plays a critical role in the regulation of oxidants and inflammation-induced VILI during hyperoxia. iPSC therapy can ameliorate acute hyperoxic VILI by suppressing the Src pathway.MethodsMale C57BL/6 mice, either wild-type or Src-deficient, aged between 2 and 3 months were exposed to high VT (30 mL/kg) ventilation with or without hyperoxia for 1 to 4 h after the administration of Oct4/Sox2/Parp1 iPSCs at a dose of 5×107 cells/kg of mouse. Nonventilated mice were used for the control groups.ResultsHigh VT ventilation during hyperoxia further aggravated VILI, as demonstrated by the increases in microvascular permeability, neutrophil infiltration, macrophage inflammatory protein-2 (MIP-2) and plasminogen activator inhibitor-1 (PAI-1) production, Src activation, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, and malaldehyde (MDA) level. Administering iPSCs attenuated ALI induced by MV during hyperoxia, which benefited from the suppression of Src activation, oxidative stress, acute inflammation, and apoptosis, as indicated by the Src-deficient mice.ConclusionThe data suggest that iPSC-based therapy is capable of partially suppressing acute inflammatory and oxidant responses that occur during hyperoxia-augmented VILI through the inhibition of Src-dependent signaling pathway.

Oral submucous fibrosis (OSF) is a precancerous condition with symptoms of limited mouth opening and areca nut chewing habit has been implicated in its pathogenesis. Hinokitiol, a natural tropolone derived from Chamacyparis taiwanensis, has been reported to improve oral lichen planus and inhibit various cancer cells. Here, we showed that hinokitiol reduced the myofibroblast activities in fBMFs and prevented the arecoline-induced transdifferentiation. Treatment of hinokitiol dose-dependently downregulated the myofibroblast markers as well as various EMT transcriptional factors. In particular, we identified that Snail was able to bind to the E-box in the α-SMA promoter. Our data suggested that exposure of fBMFs to hinokitiol mitigated the hallmarks of myofibroblasts, while overexpression of Snail eliminated the effect of hinokitiol. These findings revealed that the inhibitory effect of hinokitiol on myofibroblasts was mediated by repression of α-SMA via regulation of Snail and showed the anti-fibrotic potential of hinokitiol in the treatment of OSF.

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.