Yuzheng Zhuge

Proton pump inhibitor pantoprazole abrogates adriamycin-resistant gastric cancer cell invasiveness via suppression of Akt/GSK-β/β-catenin signaling and epithelial–mesenchymal transition

The effect of proton pump inhibitor (PPI) on cancer risk has received much attention recently. In this study, we investigated the mechanism underlying multidrug resistance and the effect of a PPI pantoprazole using an adriamycin-resistant gastric cancer cell model (SGC7901/ADR). Compared with the parental cell line, SGC7901/ADR cells showed reduced proliferation rate, but higher resistance to adriamycin under both anchorage-dependent and -independent conditions. Notably, SGC7901/ADR cells underwent epithelial to mesenchymal transition (EMT) and showed increased migrating and invading capabilities. At molecular level, SGC7901/ADR cells showed strong activation of Wnt/β-catenin signaling pathway compared with parental sensitive cells. Interestingly, we found that a PPI pantoprazole can effectively reverse the aggressiveness and EMT marker expression of SGC7901/ADR cells. Furthermore, pantoprazole treatment resulted in a profound reduction of both total and phosphorylated forms of Akt and GSK-3β, which in turn suppressed the adriamycin-induced Wnt/β-catenin signaling in SGC7901/ADR cells. Taken together, we demonstrate that the aggressive phenotype of adriamycin-resistant SGC7901/ADR cells is mediated by induction of EMT and activation of the canonical Wnt/β-catenin signaling pathway. And for the first time, we show that it is possible to suppress the invasiveness of SGC7901/ADR cells by pantoprazole which targets the EMT and Akt/GSK-3β/β-catenin signaling.

TWEAK increases SIRT1 expression and promotes p53 deacetylation affecting human hepatic stellate cell senescence

To detect the effects of tumor necrosis factor‐like weak inducer of apoptosis (TWEAK) on SIRT1 expression and p53 deacetylation, involving cell senescence, in activated human hepatic stellate cell (HSC) in vitro, human HSC LX‐2 was cultured with TWEAK for 24 h. The result showed that the expression of membrane receptor Fn14 was remarkably increased by TWEAK, which upregulated SIRT1 in LX‐2 cells, detected by Western blotting and real‐time PCR. The expression of p53 was not significantly altered; however, the ac‐p53 was decreased. Furthermore, the viability of LX‐2 cells was significantly enhanced by TWEAK. The activity of SA‐β‐Gal was notably inhibited, showing a suppressing effect of TWEAK on the senescence of activated HSC. Primary cultured HSC on days 7 and 11 was used to examine the expression of TWEAK, Fn14, SIRT1, and the activity of SA‐β‐Gal. The result indicated that the mRNA of TWEAK, SIRT1, and Fn14 was all decreased on day 11 compared to that on day 7, and the activity of SA‐β‐Gal was higher on day 11 than that on day 7. The present study suggested that TWEAK enhanced the expression of SIRT1 and decreased the acetylation of p53, probably inhibiting the senescence of activated HSC in vitro, which provides a molecular basis for TWEAK as a potential target in the therapy of liver fibrosis.

Etoposide Induces Apoptosis in Activated Human Hepatic Stellate Cells via ER Stress

The activation of hepatic stellate cells (HSCs) plays a vital role in the progression of liver fibrosis, and the induction of HSCs apoptosis may attenuate or reverse fibrogenesis. The therapeutic effects of etoposide(VP-16), a widely used anticancer agent, on HSCs apoptosis and liver fibrosis resolution are still unclear. Here, we report that VP-16 reduced the proliferation of LX-2 cells and led to significantly high levels of apoptosis, as indicated by Annexin V staining and the proteolytic cleavage of the executioner caspase-3 and PARP. Additionally, the unfolded protein response regulators CHOP, BIP, caspase-12, p-eIF2α and IRE1α, which are considered endoplasmic reticulum (ER) stress markers, were upregulated by VP-16. The strong inhibitory effect of VP-16 on LX-2 cells was mainly dependent on ER stress, which activated JNK signaling pathway. Remarkably, VP-16 treatment decreased the expression of α-SMA and type I collagen and simultaneously increased the ratio of matrix metalloproteinases (MMPs) to tissue inhibitor of matrix metalloproteinases (TIMPs). In contrast, VP-16 induced significantly more apoptosis in HSCs than in normal hepatocytes. Taken together, our findings demonstrate that VP-16 exerts a proapoptotic effect on LX-2 cells and has an antifibrogenic effect on collagen deposition, suggesting a new strategy for the treatment of liver fibrosis.

A Strategy to Delay the Development of Cisplatin Resistance by Maintaining a Certain Amount of Cisplatin-Sensitive Cells

Cisplatin (ddp), which is commonly employed in the treatment of many advanced cancers, often results in initial therapeutic success; however, rapid progression of ddp-resistant cells remains the main reason for treatment failure. Facd with such a problem, we investigated the fitness differences between ddp-sensitive and ddp-resistant cell lines. We found that the growth of ddp-resistant cells was significantly slower than that of sensitive cells due to elevated ROS levels, which suggested that the ddp resistance mechanisms may have negative impacts on the growth of resistant cells. Furthermore, we observed that, when mixed with ddp-sensitive cells, ddp-resistant cells failed to compete, and the growth of ddp-resistant cells could therefore be suppressed by treatment in vivo. We propose a mathematical model parameterized based on in vivo experiments to describe the allometric growth of tumors consisting of two competing subclones. According to our model, a quantitative strategy with a variant drug-dosing interval is proposed to control tumor growth. Taking advantage of intratumoral competition, our strategy with appropriate dosing intervals could remarkably delay the development of ddp resistance and prolong overall survival. Maintaining a certain number of ddp-sensitive cells rather than eradicating the tumor with continuous treatment is feasible for future tumor treatment.

Different scoring systems in predicting survival in Chinese patients with liver cirrhosis undergoing transjugular intrahepatic portosystemic shunt.

Background Transjugular intrahepatic portosystemic shunt (TIPS) is an established minimal-invasive procedure to treat complications of portal hypertension, and several scoring systems have been used to help choose suitable patients. However, its accuracy remains controversial. Aim To compare the performance of the Child–Turcotte–Pugh (CTP) classification system, model for end-stage liver disease (MELD) score, Emory score, Bonn TIPS early mortality (BOTEM) score, and serum bilirubin and platelet count (SB/PLT model) in predicting survival in Chinese patients with liver cirrhosis undergoing TIPS. Patients and methods The clinical data of patients undergoing TIPS in our department were retrospectively analyzed to compare the five scoring systems on the basis of survival after TIPS. Results A cohort of 159 patients was analyzed. The survival curves showed a statistical significance between classification B and C of CTP (&khgr;2=9.451, P=0.002), between MELD less than 10 and MELD at least 10 (&khgr;2=10.099, P=0.001), and between low-risk and moderate-risk groups of the Emory score (&khgr;2=4.656, P=0.031), indicating a better discriminatory ability. By ROC curves and a logistic regression model, the MELD score and the CTP system had better power to predict 3-, 12-, and 24-month survival. The MELD score and the CTP classification system had smaller values of −2 Ln(L), Akaike Information criterion, and Schwarz–Bayesian criterion, respectively. Conclusion The MELD score and the CTP classification system provide better prognostic stratification for a cohort of Chinese patients with advanced cirrhosis undergoing TIPS. However, the MELD score is not significantly superior to the CTP system.

Downregulation of leucine-rich repeats and immunoglobulin-like domains 1 by microRNA-20a modulates gastric cancer multidrug resistance

Multidrug resistance (MDR) significantly restricts the clinical efficacy of gastric cancer (GC) chemotherapy, and it is critical to search novel targets to predict and overcome MDR. Leucine‐rich repeats and immunoglobulin‐like domains 1 (LRIG1) has been proved to be correlated with drug resistance in several cancers. The present study revealed that LRIG1 was overexpressed in chemosensitive GC tissues and decreased expression of LRIG1 predicted poor survival in GC patients. We observed that upregulation of LRIG1 enhanced chemosensitivity in GC cells. Interestingly, miR‐20a, which was overexpressed in GC MDR cell lines and tissues, was identified to regulate LRIG1 expression by directly targeting its 3′ untranslated region. We also found that inhibition of miR‐20a suppressed GC MDR, and upregulation showed opposite effects. Moreover, we demonstrated that the miR‐20a/LRIG1 axis regulated GC cell MDR through epidermal growth factor receptor (EGFR)‐mediated PI3K/AKT and MAPK/ERK signaling pathways. Finally, LRIG1 expression in human GC tissues is inversely correlated with miR‐20a and EGFR. Taken together, the newly identified miR‐20a/LRIG1/EGFR link provides insight into the MDR process of GC, and targeting this axis represents a novel potential therapeutic strategy to block GC chemoresistance.

Influence of CYP2D6 and β2-adrenergic receptor gene polymorphisms on the hemodynamic response to propranolol in Chinese Han patients with cirrhosis.

Propranolol is widely used to prevent gastroesophageal variceal bleeding; however, some patients could not benefit from propranolol. This study is to evaluate the relationship between CYP2D6 and β2‐adrenergic receptor (β2‐AR) gene polymorphisms and the hemodynamic response to propranolol in Chinese Han patients.

Increased Glutamine Consumption in Cisplatin-Resistant Cells Has a Negative Impact on Cell Growth

The emergence of drug-resistant subclones remains the primary reason for tumor treatment failure. Some theories suggest that drug-resistant cell growth can be suppressed by drug-sensitive cells because resistant cells are less fit than sensitive cells in the absence of drug. We investigated fitness differences and their underlying mechanisms in cisplatin (ddp)-resistant cells and parental cells. We found that glutamine (Gln) consumption was substantially higher in ddp-resistant cells than that in sensitive cells, indicating that significantly fewer ddp-resistant cells than sensitive cells could be generated under the same Gln conditions. Interestingly, the antioxidant capacity of ddp-resistant cells was also significantly enhanced and was directly related to the presence of Gln. Then, we found that enhanced antioxidant capacity was sustained by accelerated Gln catabolism in resistant cells through oncogenic KRAS. Further analysis indicated that rapid Gln catabolism directly mediated ddp resistance through enhanced antioxidant capacity, but the maximum number of resistant cells that could be produced with the same amount of Gln was significantly reduced due to increased Gln catabolism. Collectively, our study revealed that rapid Gln catabolism provided ddp-resistant cells with the ability to tolerate cytotoxic treatment but also hindered the growth of ddp-resistant cells due to excessive Gln consumption.

Upregulation of UBE2Q1 via gene copy number gain in hepatocellular carcinoma promotes cancer progression through β-catenin-EGFR-PI3K-Akt-mTOR signaling pathway†

Hepatocellular carcinoma (HCC) is the most common type of liver cancer and represents a highly malignant tumor with a poor prognosis. Therapeutic modalities for HCC are limited and generally ineffective. UBE2Q1 is a putative E2 ubiquitin conjugating enzyme, and has been shown to be overexpressed in various types of cancers including HCC. How UBE2Q1 contributes to hepatocarcinogenesis remains unknown. Here, we show that UBE2Q1 is up‐regulated in HCC cell lines and in a subset of human HCC tissues. Up‐regulation of UBE2Q1 in primary HCC tumors was significantly correlated with shorter overall survival and disease‐free survival. Mechanistically, we showed that the frequent up‐regulation of UBE2Q1 in HCCs was attributed to the recurrent UBE2Q1 gene copy gain at chromosome 1q21. Functionally, we showed that knockdown of UBE2Q1 reduced HCC cell proliferation, promoted apoptosis via induction of GADD45α, and suppressed orthotopic tumorigenicity both in vitro and in vivo. Inactivation of UBE2Q1 also impeded HCC cell migration and invasion in vitro through regulating EMT process, and suppressed HCC metastasis in vivo. Interestingly, our data revealed a role of UBE2Q1 in the regulation of β‐catenin‐EGFR‐PI3K‐Akt‐mTOR signaling pathway. Our findings indicate that UBE2Q1 is a candidate oncogene involved in HCC development and progression and therefore a potential therapeutic target in applicable HCC patients.

The proton pump inhibitor pantoprazole disrupts protein degradation systems and sensitizes cancer cells to death under various stresses

Proton pump inhibitors (PPIs) play a role in antitumor activity, with studies showing specialized impacts of PPIs on cancer cell apoptosis, metastasis, and autophagy. In this study, we demonstrated that pantoprazole (PPI) increased autophagosomes formation and affected autophagic flux depending on the pH conditions. PPI specifically elevated SQSTM1 protein levels by increasing SQSTM1 transcription via NFE2L2 activation independent of the specific effect of PPI on autophagic flux. Via decreasing proteasome subunits expression, PPI significantly impaired the function of the proteasome, accompanied by the accumulation of undegraded poly-ubiquitinated proteins. Notably, PPI-induced autophagy functioned as a downstream response of proteasome inhibition by PPI, while suppressing protein synthesis abrogated autophagy. Blocking autophagic flux in neutral pH condition or further impairing proteasome function with proteasome inhibitors, significantly aggravated PPI cytotoxicity by worsening protein degradation ability. Interestingly, under conditions of mitochondrial stress, PPI showed significant synergism when combined with Bcl-2 inhibitors. Taken together, these findings provide a new understanding of the impact of PPIs on cancer cells’ biological processes and highlight the potential to develop more efficient and effective combination therapies.