Reactivation of mutant p53 in esophageal squamous cell carcinoma by isothiocyanate inhibits tumor growth

p53 mutations are prevalent in human cancers; approximately half of patients with esophageal cancer present these mutations. Mutant p53 (mutp53) exerts oncogenic functions that promote malignant tumor progression, invasion, metastasis, and drug resistance, resulting in poor prognosis. Some small molecules have been shown to mitigate the oncogenic function of mutp53 by restoring its wild-type activity. Although these molecules have been evaluated in clinical trials, none have been successfully used in the clinic. Here, we investigated the antitumor effects of phenethyl isothiocyanate (PEITC) in p53-mutant esophageal squamous cell carcinoma (ESCC) and elucidated its mechanism to identify new therapeutic strategies. We observed that p53R248Q is a DNA contact mutation and a structural mutation and that PEITC can restore the activity of p53R248Qin vitro and in vivo, further clarifying the antitumor activity of PEITC in cancers with different types of p53 mutations. PEITC can inhibit ESCC growth, induce apoptosis, and arrest cell cycle progression and has a preferential selectivity for ESCC with p53 mutations. Mechanistic studies showed that PEITC induced apoptosis and arrested cells at G2/M transition in cells expressing the p53R248Q mutant by restoring the wild-type conformation and transactivation function of p53; these effects were concentration dependent. Furthermore, PEITC inhibited the growth of subcutaneous xenografts in vivo and restored p53 mutant activity in xenografts. According to these findings, PEITC has antitumor effects, with its ability to restore p53R248Q activity being a key molecular event responsible for these effects

Exploration of Immune Tolerance and Treatment for Esophageal Cancer

Monoclonal antibody drugs that inhibit programmed death 1 (PD-1) or programmed death ligand 1 (PD-L1) have been widely used in esophageal cancer (EC) and yielded significant therapeutic responses. However, only a few patients obtain lasting clinical benefits due to primary or acquired drug resistance, and new treatment schemes are urgently needed. The tumor immune microenvironment is the main factor that affects patients' response to immunosuppressive agents. This article will discuss the role of immunosuppressive cells and non-cellular components in the immune process to provide ideas for the next research direction of EC

Density Functional Theory Study of the Oxygen Chemistry and NO Oxidation Mechanism on Low-Index Surfaces of SmMn₂O₅ Mullite

SmMn₂O₅ mullite has recently been reported to be a promising alternative to traditional Pt-based catalysts for environmental and energy applications. By performing density functional theory calculations, we have systematically investigated lattice oxygen reactivity and oxygen adsorption/dissociation/migration behaviors on low-index surfaces of SmMn₂O₅ mullite with different terminations. On the basis of the oxygen chemistry and thermodynamic stability of different facets, we conclude that (100)³⁺, (010)⁴⁺, and (001)⁴⁺ are reactive toward NO oxidation via either the Mars van Krevelen (MvK) or Eley–Rideal (ER) mechanism. Concrete NO → NO₂ reaction paths on these candidate mechanisms have also been calculated. Both the (010)⁴⁺ and (001)⁴⁺ surfaces presented desirable activities. Bridge MnO sites on (010)⁴⁺ surface are identified to be the most active for NO oxidation through the ER mechanism with the lowest barrier of ∼0.38 eV. We have also identified that on all active sites considered in the current study, the rate-determining step in NO → NO₂ oxidation reaction is the NO₂ desorption. Our study gives an insight into the mechanisms of NO oxidation on SmMn₂O₅ mullite at the atomic level and can be used to guide further improvement of its catalytic performance

CpG-Oligodeoxynucleotides Alleviate Tert-Butyl Hydroperoxide-Induced Macrophage Apoptosis by Regulating Mitochondrial Function and Suppressing ROS Production

Oxidative stress and mitochondrial dysfunction are related to disease pathogenesis. Oligodeoxynucleotide containing CpG motifs (CpG ODN) demonstrate possibilities for immunotherapy applications. The aim of the present work is to explore the underlying mechanism of the cytoprotective function of CpG ODN by employing the oxidative stress modulation in immune cells. We used the imaging flow cytometry to demonstrate that tert-butyl hydroperoxide (t-BHP) induces mitochondrial-mediated apoptosis and ROS production in RAW264.7 cells. After pretreatment with CpG ODN, the percentage of apoptotic cells and ROS production was both markedly reduced. The decrease in mitochondrial membrane potential (MMP) induced by t-BHP was partially reversed by CpG ODN. The t-BHP induced upregulation of the expression of apoptosis-related proteins (cleaved-caspase 3, cleaved-caspase 9, cleaved-PARP, and bax) was notably decreased in the presence of CpG ODN. Furthermore, we found that CpG ODN enhanced phosphorylation of ERK1/2 and Akt to inhibit ROS production. In conclusion, the protective effect of CpG ODN in mitigation of t-BHP-induced apoptosis is dependent on the reduction of ROS

Metformin inhibited esophageal squamous cell carcinoma proliferation in vitro and in vivo and enhanced the anti-cancer effect of cisplatin.

Esophageal squamous cell carcinoma (ESCC) is an aggressive malignancy with poor prognosis in China. Chemotherapy now is one of the most frequently used treatments for patients with ESCC in middle or late stage, however the effects were often limited by increased chemoresistance or treatment toxicity. So it is urgent to find new drugs to treat ESCC patients. Metformin with low cost and toxicity has proved to have anti-cancer effects in a numerous cancers, while its role and mechanism in ESCC has seldom been studied. In the present study, we found that metformin exhibited not only an anti-proliferation ability in a dose and time dependent manner but also a proapoptosis effect in a dose dependent manner in ESCC cell line KYSE450. Our in vivo experiment also showed that metformin markedly inhibited KYSE450 xenograft tumors growth compared to those treated with normal saline. What's more, no obvious toxic reactions were observed. To further explore the underlying mechanism, we found that metformin treatment could significantly damp the expression of 4EBP1 and S6K1 in KYSE 450 cells in vitro and in vivo, furthermore, the p-4EBP1 and p-S6K1 expression in KYSE 450 cells were also inhibited greatly in vitro and in vivo. During the therapy of cancer, in order to overcome side effects, combination therapy was often used. In this paper, we demonstrated that metformin potentiated the effects of cisplatin via inhibiting cell proliferation and promoting cell apoptosis. Taken together, metformin owned the potential anti-cancer effect on ESCC in monotherapy or was combined with cisplatin and these results laid solid basis for the use of metformin in ESCC

Targeting adaptor protein SLP76 of RAGE as a therapeutic approach for lethal sepsis

RAGE signalling is implicated in sepsis. Here the authors use T7 phage display to identify SLP76 as a binding partner for the cytosolic tail of RAGE and provide a reagent that can block this interaction and protect mice from sepsis in a caecal ligation and puncture model

Metformin inhibited 4EBP1 and S6K1 expression in vivo.

<p>Xenograft tumors were harvested, fixed and paraffin-embedded, and stained for 4EBP1, S6K1, p-4EBP1 and p- S6K1 by immunohistochemistry. The protein expression of 4EBP1 and S6K1 were mainly located in the nuclear and cytoplasm of the KYSE450 cells. Immunohistochemical examination exhibited decreased average density of stain for 4EBP1 and S6K1 in metformin treated group than those in control group. The protein expression of p-4EBP1 and p-S6K1 were mainly located in the nuclear of the KYSE450 cells. And the immunohistochemical examination exhibited decreased average density of stain for p-4EBP1 and p-S6K1 in metformin treated group than those in control group. <b>A.</b> The protein expression of 4EBP1 in metformin group (a) and control group (b). <b>B.</b> The protein expression of S6K1 in metformin group (a) and control group (b). <b>C.</b> The protein expression of p-4EBP1 in metformin group (a) and control group (b). <b>D.</b> The protein expression of p-S6K1 in metformin group (a) and control group (b).</p

Effects of metformin on the proliferation and apoptosis ability of KYSE 450 cells.

<p>A. KYSE 450 cells treated with 5, 10, 20 and 40mmol/L metformin for 24, 48, 72h and cell proliferation was measured by MTT assay. The results revealed that the inhibition rate of the proliferation ability of KYSE 450 cells increased significantly with the time going and concentration rising. *P<0.01 denotes a significant difference between different concentration at the same time point; **P<0.05 denoted a significant difference between different time point at the same concentration. B. Annexin V-FITC/PI was used to analyze of apoptosis ability of KYSE 450 cells treated with 0, 5, 10 and 20 mmol/L metformin. With the increase of concentration, the percentage of apoptotic cells improved markedly. a was the control group, b-d were the group of 5, 10, 20 mmol/L metformin respectively. **P<0.05 denoted a significant difference between different concentration.</p

The combination effects of metformin and cisplatin on the proliferation and apoptosis ability of KYSE 450 cells.

<p>A. KYSE 450 cells treated with 5, 10, 20 and 40mmol/L metformin combined with 10ug/ml cisplatin for 24, 48h and cell proliferation was measured by MTT assay. The results showed that metformin enhanced the inhibition rate of cisplatin on the proliferation of KYSE450 cells. Furthermore, the inhibition rate increased with the increase of the concentration of metformin. *P<0.01 or **P<0.05 denotes a significant difference between different concentration at the same time point; ***P<0.05 denoted a significant difference between different time point at the same concentration. B. Annexin V-FITC/PI was used to analyze of apoptosis ability of KYSE 450 cells treated with 0, 5, 10 and 20 mmol/L metformin and cisplatin(10ug/mL) at the same time. The results demonstrated that metformin could also improve the apoptosis caused by cisplatin and the percentage of apoptotic cells increased with the rising concentration of metformin. **P<0.05 denoted a significant difference between different concentration.</p

Metformin inhibited tumor growth in vivo.

<p><b>A.</b>KYSE 450 xenograft treated with metformin (35.75 mg/kg/d) for 15 days were smaller than those treated with normal saline. <b>B.</b> Tumor volume were significantly reduced in metformin treated group than control group. ***P < 0.0001, denoted a markable difference between the size and volume of tumor-bearing nude mice of control group and metformin group. <b>C.</b> HE stain showed that the area of necrosis in xenograft tumors derived from metformin treated group were about 50% larger than those derived from control group.</p