Matrix Stiffness-Upregulated MicroRNA-17-5p Attenuates the Intervention Effects of Metformin on HCC Invasion and Metastasis by Targeting the PTEN/PI3K/Akt Pathway.

BACKGROUND: Metformin, a traditional first-line anti-hyperglycemic agent for diabetes, recently exhibits better antitumor effect in hepatocellular carcinoma (HCC). However, its resistance and tolerance mechanism in HCC remains largely unknown. Here, we investigated whether increased matrix stiffness attenuated the intervention effects of metformin on HCC invasion and metastasis, and explored its underlying molecular mechanism. METHODS: FN-coated gel substrates with 6, 10, and 16 kPa, which simulated the stiffness of normal, fibrotic, and cirrhotic liver tissues respectively, were established to evaluate matrix stiffness-mediated effects on HCC cells. Alterations in morphology, proliferation, motility, and invasive/metastatic-associated genes (PTEN, MMP2, MMP9) of HCC cells grown on different-stiffness substrates were comparatively analyzed before and after metformin intervention. Subsequently, the underlying molecular mechanism by which higher matrix stiffness attenuates antitumor effects of metformin in HCC was further elucidated. RESULTS: Metformin significantly inhibited proliferation, migration, and invasion of HCC cells. Compared with the controls on lower-stiffness substrate, HCC cells grown on higher-stiffness substrate exhibited an obvious resistance to intervention effects of metformin on proliferation, migration, invasion and metastasis. High stiffness stimulation significantly activated the miR-17-5p/PTEN/PI3K/Akt signaling pathway in HCC cells via integrin ß1 and in turn resulted in MMP2 and MMP9 upregulation. Meanwhile, integrin ß1 knockdown or PI3K inhibitor partially reversed the activation of the above signaling molecules. For HCC cells grown on the same-stiffness substrate, metformin remarkably upregulated PTEN expression and suppressed the activation of the PI3K/Akt/MMP pathway, but no effect on integrin ß1 expression. Importantly, the increase in fold of PTEN expression and decrease in folds of Akt phosphorylation level and MMP2 and MMP9 expressions in the treated HCC cells with metformin on 16-kPa stiffness substrate were evidently weakened compared with those in the controls on the 6-kPa stiffness substrate. CONCLUSIONS: Increased matrix stiffness significantly attenuates the inhibitory effect of metformin on HCC invasion and metastasis, and a common pathway of PTEN/PI3K/Akt/MMPs activated by mechanical stiffness signal and inactivated by metformin contributes to matrix stiffness-caused metformin resistance. To the best of our knowledge, this is the first report to clarify the mechanism of metformin intervention resistance from the perspective of tumor biophysical microenvironment.

Easier operation and similar power of 10 g monofilament test for screening diabetic peripheral neuropathy.

Objective The 10 g Semmes-Weinstein monofilament evaluation (SWME) of 4 sites on each foot is recommended for distal symmetric polyneuropathy screening and diagnosis. A similar method has been proposed to diagnose 'high-risk' (for ulceration) feet, using 3 sites per foot. This study compared the effectiveness of SWME for testing 3, 4 and 10 sites per foot to identify patients with diabetic neuropathy. Methods We included 3497 subjects in a SWME of 10 sites; records from the 10-site SWME were used for a SWME of 3 and 4 sites. Neuropathy symptom scores and neuropathy deficit scores were evaluated to identify patients with diabetic peripheral neuropathy. Results The sensitivities of the 10 g SWME for 3, 4 and 10 sites were 17.8%, 19.0% and 22.4%, respectively. The Kappa coefficients for the SWME tests of 3, 4 and 10 sites were high (range: 0.78-0.93). Conclusions There were no significant differences in the effectiveness of 3-, 4- and 10-site SWME testing for diabetic peripheral neuropathy screening. SWME testing of 3 sites on each foot may be sufficient to screen for diabetic neuropathy.

Cinnamaldehyde induces fat cell-autonomous thermogenesis and metabolic reprogramming.

OBJECTIVE: Cinnamaldehyde (CA) is a food compound that has previously been observed to be protective against obesity and hyperglycemia in mouse models. In this study, we aimed to elucidate the mechanisms behind this protective effect by assessing the cell-autonomous response of primary adipocytes to CA treatment. METHODS: Primary murine adipocytes were treated with CA and thermogenic and metabolic responses were assessed after both acute and chronic treatments. Human adipose stem cells were differentiated and treated with CA to assess whether the CA-mediated signaling is conserved in humans. RESULTS: CA significantly activated PKA signaling, increased expression levels of thermogenic genes and induced phosphorylation of HSL and PLIN1 in murine primary adipocytes. Inhibition of PKA or p38 MAPK enzymatic activity markedly inhibited the CA-induced thermogenic response. In addition, chronic CA treatment regulates metabolic reprogramming, which was partially diminished in FGF21KO adipocytes. Importantly, both acute and chronic effects of CA were observed in human adipose stem cells isolated from multiple donors of different ethnicities and ages and with a variety of body mass indexes (BMI). CONCLUSIONS: CA activates thermogenic and metabolic responses in mouse and human primary subcutaneous adipocytes in a cell-autonomous manner, giving a mechanistic explanation for the anti-obesity effects of CA observed previously and further supporting its potential metabolic benefits on humans. Given the wide usage of cinnamon in the food industry, the notion that this popular food additive, instead of a drug, may activate thermogenesis, could ultimately lead to therapeutic strategies against obesity that are much better adhered to by participants.

C-peptide is independent associated with diabetic peripheral neuropathy: a community-based study.

BACKGROUND: Because the relationship between C-peptide and diabetic peripheral neuropathy (DPN) is controversial, the aim of our study was to evaluate the relationship between C-peptide and DPN in community-based Chinese patients with type 2 diabetes. METHODS: In total, 220 consecutive type 2 diabetic patients treated by our regional medical consortium were enrolled. DPN was assessed by clinical symptoms, signs, and electromyography. RESULTS: Fasting C-peptide, 2-h postprandial C-peptide and ΔC-peptide (i.e., 2-h postprandial C-peptide minus the fasting C-peptide) serum concentrations in the non-DPN group were significantly higher than those in the clinical DPN group (all P ≤ 0.040) and the confirmed DPN group (all P < 0.002). The three C-peptide parameters were independently associated with DPN (all P < 0.05) after adjusting for age, sex, diabetes duration, smoking status, systolic pressure, body mass index, angiotensin-converting enzyme inhibitors/angiotensin receptor blocker use, fasting plasma glucose, HbA1c, triglyceride and estimated glomerular filtration rate. Compared with the ΔC-peptide quartile 1 (reference), patients in quartile 3 (odds ratio [OR], 0.110; 95% confidence interval [CI] 0.026-0.466; P = 0.003) and quartile 4 (OR, 0.012; 95% CI 0.026-0.559; P = 0.007) had a lower risk of DPN after adjusting for the confounders. CONCLUSIONS: C-peptide was negatively associated with DPN in community-based Chinese type 2 diabetic patients in China.

The value of prolactin in inferior petrosal sinus sampling with desmopressin stimulation in Cushing's disease.

Prolactin may reduce false-negative results in diagnosing Cushing's disease (CD) during inferior petrosal sinus sampling (IPSS). Prolactin normalization could improve the accuracy of IPSS in predicting adenoma lateralization in CD. However, none of the previous studies had involved the use of desmopressin during IPSS. Our objective was to examine the utility of prolactin measurement during IPSS with desmopressin stimulation. We conducted a retrospective analysis of 40 patients (including 31 females) with ACTH-dependent Cushing's syndrome who underwent IPSS between 2010 and 2013. Thirty-eight CD patients were partitioned into true positive (n = 35) and false negative (n = 3). The proportion of improper IPSS venous sampling defined by corresponding IPS:P (inferior petrosal sinus to peripheral) prolactin ratio <1.8 was significantly different between two groups (P = 0.004). Applying a prolactin-normalized ACTH IPS:P ratio >0.8 cutoff could increase the sensitivity of IPSS to 38/38 (100 %). Among the 31 patients with histopathologically proven adenoma localization, correct prediction of adenoma lateralization was obtained in 14/31 (45 %) patients by a peak intersinus ACTH gradient of ≥1.4 in baseline and was not improved by desmopressin stimulation. Left-right intersinus gradients of unilateral prolactin-adjusted ACTH IPS:P ratios could increase the correct prediction of adenoma lateralization to 20/31 (65 %) in baseline and 24/31 (77 %) (P = 0.006) after desmopressin stimulation, respectively. Prolactin is helpful to adjust negative results of IPSS with desmopressin stimulation. It may improve the accuracy in predicting adenoma lateralization in CD as well.