Oral Squamous Cell Carcinoma Cells with Acquired Resistance to Erlotinib Are Sensitive to Anti-Cancer Effect of Quercetin via Pyruvate Kinase M2 (PKM2).

Oral squamous cell carcinoma (OSCC) frequently carries high epidermal growth factor receptor (EGFR) expression. Erlotinib, a small molecule tyrosine kinase inhibitor (TKI), is an effective inhibitor of EGFR activity; however, resistance to this drug can occur, limiting therapeutic outcomes. Therefore, in the current study, we aimed to unveil key intracellular molecules and adjuvant reagents to overcome erlotinib resistance. First, two HSC-3-derived erlotinib-resistant cell lines, ERL-R5 and ERL-R10, were established; both exhibited relatively higher growth rates, glucose utilization, epithelial-mesenchymal transition (EMT), and invasiveness compared with parental cells. Cancer aggressiveness-related proteins, such as N-cadherin, Vimentin, Twist, MMP-2, MMP-9, and MMP-13, and the glycolytic enzymes PKM2 and GLUT1 were upregulated in ERL-R cells. Notably, ERL-R cells were sensitive to quercetin, a naturally-existing flavonol phytochemical with anti-cancer properties against various cancer cells. At a concentration of 5 µM, quercetin effectively arrested cell growth, reduced glucose utilization, and inhibited cellular invasiveness. An ERL-R5-derived xenograft mouse model confirmed the growth-inhibitory efficacy of quercetin. Additionally, knock-down of PKM2 by siRNA mimicked the effect of quercetin and re-sensitized ERL-R cells to erlotinib. Furthermore, adding quercetin blocked the development of erlotinib-mediated resistance by enhancing apoptosis. In conclusion, our data support the application of quercetin in anti-erlotinib-resistant OSCC and indicate that PKM2 is a determinant factor in erlotinib resistance and quercetin sensitivity.

Regulatory role of transcription factor HBP1 in anticancer efficacy of EGFR inhibitor erlotinib in HNSCC.

BACKGROUND: Epidermal growth factor receptor (EGFR) is often hyperactivated in head and neck squamous cell carcinoma (HNSCC); however, its downstream mediators are not fully identified. Here, we investigate the role of transcription factor HBP1 in the anticancer efficacy of EGFR inhibitor erlotinib in HNSCC. METHODS: The effect of erlotinib and HBP1 on cell proliferation and invasion was examined by flow cytometric analysis and a Matrigel invasion assay, respectively. Oral tumor specimens were used to evaluate the association between the expression level of EGFR and HBP1, and metastatic potential. RESULTS: Erlotinib caused cell growth arrest in the G1 phase and sluggish invasion with a concomitant increase in HBP1 and p27 expression. The erlotinib effect was attenuated upon HBP1 knockdown. Analysis of oral tumor specimens revealed that the low HBP1/high EGFR status can predict metastatic potential. CONCLUSIONS: Our data support HBP1 as a crucial mediator of EGFR-targeting inhibitors in HNSCC.

Bidirectional association between metabolic syndrome and osteoarthritis: a meta-analysis of observational studies.

BACKGROUND: Emerging observational studies suggest an association between metabolic syndrome (MetS) and osteoarthritis (OA). This meta-analysis was conducted to examine whether or not there is a bidirectional relationship between MetS and OA. METHODS: The PubMed and Embase databases were searched from their inception to October 2019. We selected studies according to predefined criteria. Random effects were selected to calculate two sets of pooled risk estimates: MetS predicting OA and OA predicting MetS. RESULTS: A total of seven cross-sectional studies and four cohort studies met the criteria for MetS predicting the onset of OA. Another six cross-sectional studies and one cohort study met the criteria for OA predicting the onset of MetS. The pooled odds risk (OR) for OA incidences associated with baseline MetS was 1.45 (95% CI 1.27-1.66). The OR for MetS incidences associated with baseline OA was 1.90 (95% CI 1.11-3.27). In an overall analysis, we found that MetS was associated with prevalent OA in both cross-sectional studies (OR = 1.32, 95% CI 1.21-1.44) and cohort studies (OR = 1.76, 95% CI 1.29-2.42). No indication of heterogeneity was found in the cross-sectional studies (p = 0.395, I2 = 4.8%), whereas substantial heterogeneity was detected in the cohort studies (p = 0.000, I2 = 79.3%). CONCLUSION: Meta-analysis indicated a bidirectional association between MetS and OA. We advise that patients with MetS should monitor their OA status early and carefully, and vice versa.

Helicobacter pylori isolates from ethnic minority patients in Guangxi: resistance rates, mechanisms, and genotype.

AIM: To investigate the rate of Helicobacter pylori (H. pylori) resistance to clarithromycin among ethnic minority patients in Guangxi, explore the underlying mechanisms, and analyze factors influencing genotype distribution of H. pylori isolates. METHODS: H. pylori strains were isolated, cultured and subjected to drug sensitivity testing. The 23S rRNA gene of H. pylori isolates was amplified by PCR and analyzed by PCR-RFLP and direct sequencing to detect point mutations. REP-PCR was used for genotyping of H. pylori isolates, and NTsys_2 software was used for clustering analysis based on REP-PCR DNA fingerprints. Factors potentially influencing genotype distribution of H. pylori isolates were analyzed. RESULTS: The rate of clarithromycin resistance was 31.3%. A2143G and A2144G mutations were detected in the 23S rRNA gene of all clarithromycin-resistant H. pylori isolates. At a genetic distance of 78%, clarithromycin-resistant H. pylori isolates could be divided into six groups. Significant clustering was noted among H. pylori isolates from patients with peptic ulcer or gastritis. CONCLUSION: The rate of clarithromycin resistance is relatively high in ethnic minority patients in Guangxi. Main mechanisms of clarithromycin resistance are A2143G and A2144G mutations in the 23S rRNA gene. Clarithromycin-resistant H. pylori isolates can be divided into six groups based on REP-PCR DNA fingerprints. Several factors such as disease type may influence the genotype distribution of H. pylori isolates.

A role for diallyl trisulfide in mitochondrial antioxidative stress contributes to its protective effects against vascular endothelial impairment.

Persistent hyperglycemia increases a systemic oxidative stress, causing the onset of vascular endothelial dysfunction and atherosclerosis. Diallyl trisulfide (DAT), a natural organosulfur compound in garlic, has been reported to have actions of dilating blood vessels and antibacteria, etc. In this study, models of obese diabetic rat in vivo and high glucose concentration (HG)-induced endothelial cell injury in vitro were used to investigate the protective effects of DAT on vascular endothelial injury and its underlying mechanisms. In the in vivo model, the obese diabetic rats were injected venously with DAT (5.0 mg kg(-1)d(-1)) and Vitamin E (1.0 mg kg(-1)d(-1)) respectively, once daily for 7 consecutive days. In the in vitro model, HG-injured HUVEC were treated with or without DAT (25 µmol L(-1), 50 µmol L(-1), 100 µmol L(-1)) or Vitamin E (25 µmol L(-1)) respectively for 24h. The extents of vascular endothelial injury and protective effects of DAT were evaluated. The results both in vivo and in vitro displayed that DAT-treatment significantly attenuated the endothelial cell impairments. Besides, DAT-treatment markedly decreased the levels of malondialdehyde (MDA) and reactive oxygen species, whereas elevated the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in mitochondrium. Moreover, DAT-treatment considerably improved mitochondrial respiration function. Taken together, our results suggest that DAT protects vascular endothelium from HG or hyperglycemia induced-injury by reducing mitochondrial oxidative stress. The findings provide a novel insight for DAT to potentially treat the oxidative stress diseases, i.e., atherosclerosis, diabetes, and neurodegenerative diseases.

Involvement of anion exchanger-2 in apoptosis of endothelial cells induced by high glucose through an mPTP-ROS-Caspase-3 dependent pathway.

Excess apoptosis of endothelial cells (EC) plays crucial roles in the onset and progression of vasculopathy in diabetes mellitus. Anion exchanger-2 (AE2) might be involved in the vasculopathy. However, little is known about the molecular mechanisms that AE2 mediated the apoptosis of EC. The purpose of this study was to explore the role of AE2 in the apoptosis of HUVECs induced by high glucose (HG) and its possible mechanisms. First, HUVECs were exposed to different glucose concentrations (5.5, 17.8, 35.6, 71.2 and 142.4 mmol/l, respectively, pH = 7.40) for different time points (12, 24, 48, 72, 120, and 168 h, respectively). Intracellular Cl(-) concentration ([Cl(-)]i), AE2 expression and the apoptosis were assayed. Then, 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), Cl(-)-free media or specific RNA interference (RNAi) for AE2 was used to confirm whether AE2 could mediate the apoptosis induced by HG. Finally, the mechanisms of the AE2-mediated apoptosis were investigated by detecting mitochondrial permeability transition pore (mPTP, DeltaPsim) openings, reactive oxygen species (ROS) levels and Caspase-3 activity. We found that HG upregulated the AE2 expression and activity, increased [Cl(-)]i and induced the apoptosis in a time- and concentration-dependent manner. The apoptosis of HUVECs by HG was possibly mediated by AE2 through an mPTP-ROS-Caspase-3 dependent pathway. These findings suggested that AE2 was likely to be a glucose-sensitive transmembrane transporter and a novel potential therapeutic target for diabetic vasculopathy.

[Effects of nuclear factor-kappa B p65 ASODN on transforming growth beta-1 and intercellular adhesion molecule-1 of rat hepatic stellate cells].

OBJECTIVE: To study the effects of nuclear factor (NF)-kappa B p65 ASODN on transforming growth factor beta-1 (TGF beta 1) and intercellular adhesion molecule-1 (ICAM-1) of rat hepatic stellate cells (HSC) and the mechanisms of NF-kappa B p65 ASODN in treating liver fibrosis. METHODS: Type IV collagen enzyme digestion and density centrifugation methods were used to separate rat hepatic stellate cells. NF-kappa B p65 ASODN was manually synthesized and completely phosphorothioate-modified. The changes of TGF beta 1 and ICAM-1 mRNA were detected by RT-PCR and albumen of TGF beta 1 and ICAM-1 were detected by ELISA. The changes of NF-kappa B activity were determined by ELISA. RESULTS: NF-kappa B activity and the expressions of ICAM-1 and TGF beta 1 increased after the HSC were treated by TNF alpha. NF-kappa B activity weakened after being treated with NF-kappa B p65 ASODN (0.001-1.000 micromol/L), P less than 0.05 in a dose dependent manner. Transferring NF-kappa B p65 ASODN (0.001-1.000 micromol/L) also weakened the expression of ICAM-1 and TGF beta 1 mRNA and the protein induced by TNF alpha in HSC. It was also in a dose dependent manner, P less than 0.05. CONCLUSIONS: After transferring NF-kappa B p65 ASODN into HSC, their NF-kappa B activity decreased, and their mRNA and protein expressions of ICAM-1 and TGF beta 1 also decreased. This may serve as a new way in treating hepatic fibrosis.

[Comparison of esomeprazole- and omeprazole-based triple therapy regimens for duodenal ulcer with Helicobacter pylori infection].

OBJECTIVE: To investigate the effect of esomeprazole- and omeprazole-based triple therapy regimens in the treatment of duodenal ulcer with Helicobacter pylori (Hp) infection. METHODS: Totally 104 patients with duodenal ulcer and Hp infection were randomly divided into group A (52 cases) treated with esomeprazole (20 mg), amoxicillin (1000 mg) and clarithromycin (500 mg) twice daily and group B (52 cases) treated with omeprazole (20 mg), amoxicillin (1000 mg) and clarithromycin (500 mg) twice daily. The treatment lasted for 7 days, after which abdominal pain relief rate, ulcer healing rate and eradication rate of Hp as well as adverse effects of the medication were evaluated and compared. RESULTS: On the first and second days of medication, the abdominal pain relief rates were 34.6% and 59.6% respectively in group A, significantly higher than those in group B (17.3% and 38.5%, respectively, P<0.05). Ulcer healing rate and Hp eradication rate were 92.3% and 88.5 % in group A, and 88.5% and 82.7% in group B, showing no significant differences between the two groups (P>0.05). The adverse effects of the medication were rare in both groups without significant differences. CONCLUSION: Esomeprazole-based triple therapy may effectively eradicate Hp infection and promote duodenal ulcer healing with good tolerance, capable of achieving more speedy pain relief than omeprazole-based therapy.