Evaluation of Δ2-pioglitazone, an analogue of pioglitazone, on colon cancer cell survival: Evidence of drug treatment association with autophagy and activation of the Nrf2/Keap1 pathway

The Dual Role of NRF2 in Colorectal Cancer: Targeting NRF2 as a Potential Therapeutic Approach

Colorectal cancer (CRC), as the third most common bisexual cancer worldwide, requires urgent research on its underlying mechanisms and intervention methods. NRF2 is an important transcription factor involved in the regulation of redox homeostasis, protein degradation, DNA repair, and other cancer processes, playing an important role in cancer. In recent years, the complex role of NRF2 in CRC has been continuously revealed: on the one hand, it exhibits a chemopreventive effect on cancer by protecting normal cells from oxidative stress, and on the other hand, it also exhibits a protective effect on malignant cells. Therefore, this article explores the dual role of NRF2 and its related signaling pathways in CRC, including their chemical protective properties and promoting effects in the occurrence, development, metastasis, and chemotherapy resistance of CRC. In addition, this article focuses on exploring the regulation of NRF2 in CRC ferroptosis, as well as NRF2 drug modulators (activators and inhibitors) targeting CRC, including natural products, compounds, and traditional Chinese medicine formulations.

A novel BH3 mimetic Bcl-2 inhibitor promotes autophagic cell death and reduces in vivo Glioblastoma tumor growth

Anti-apoptotic members of the Bcl-2 family proteins play central roles in the regulation of cell death in glioblastoma (GBM), the most malignant type of brain tumor. Despite the advances in GBM treatment, there is still an urgent need for new therapeutic approaches. Here, we report a novel 4-thiazolidinone derivative BH3 mimetic, BAU-243 that binds to Bcl-2 with a high affinity. BAU-243 effectively reduced overall GBM cell proliferation including a subpopulation of cancer-initiating cells in contrast to the selective Bcl-2 inhibitor ABT-199. While ABT-199 successfully induces apoptosis in high BCL2-expressing neuroblastoma SHSY-5Y cells, BAU-243 triggered autophagic cell death rather than apoptosis in GBM A172 cells, indicated by the upregulation of BECN1, ATG5, and MAP1LC3B expression. Lc3b-II, a potent autophagy marker, was significantly upregulated following BAU-243 treatment. Moreover, BAU-243 significantly reduced tumor growth in vivo in orthotopic brain tumor models when compared to the vehicle group, and ABT-199 treated animals. To elucidate the molecular mechanisms of action of BAU-243, we performed computational modeling simulations that were consistent with in vitro results. Our results indicate that BAU-243 activates autophagic cell death by disrupting the Beclin 1:Bcl-2 complex and may serve as a potential small molecule for treating GBM.

Activation of β2-Adrenergic Receptor Promotes Growth and Angiogenesis in Breast Cancer by Down-regulating PPARγ

Purpose

Chronic stress and related hormones are key in cancer progression. Peroxisome proliferator-activated receptor γ (PPARγ) and its agonists was reported that inducing anti-tumor effect. However, the function of PPARγ in pro-tumorigenic effects induced by chronic stress in breast cancer remains unknown. Herein, we have characterized a novel role of PPARγ and vascular endothelial growth factor (VEGF)/fibroblast growth factor 2 (FGF2) signals in breast cancer promoted by chronic stress.

Materials and Methods

We performed experiments in vivo and in vitro and used bioinformatics data to evaluate the therapeutic potential of PPARγ in breast cancer promoted by stress.

Results

Chronic stress significantly inhibited the PPARγ expression and promoted breast cancer in vivo. VEGF/FGF2-mediated angiogenesis increased in the chronic stress group compared to the control group. PPARγ agonist pioglitazone (PioG) injection offset the pro-tumorigenic effect of chronic stress. Moreover, specific β₂-adrenergic receptor (β₂R) antagonist ICI11-8551 inhibited the effect of chronic stress. In vitro, norepinephrine (NE) treatment had a similar tendency to chronic stress. The effect of NE was mediated by the β₂R/adenylate cyclase signaling pathway and suppressed by PioG. PPARγ suppressed VEGF/FGF2 through reactive oxygen species inhibition. Bioinformatics data confirmed that therewas a lowPPARγ expression in breast invasive carcinoma. Lower PPARγ was associated with a significantly worse survival.

Conclusion

β₂R activation induced by chronic stress and related hormones promotes growth and VEGF/FGF2-mediated angiogenesis of breast cancer by down-regulating PPARγ. Our findings hint that β receptor and PPARγ as two target molecules and the novel role for their agonists or antagonists as clinical medicine in breast cancer therapy

Rosiglitazone enhances the apoptotic effect of 5-fluorouracil in colorectal cancer cells with high-glucose-induced glutathione

Colorectal cancer is one of the most prevalent noncommunicable diseases worldwide. 5-Fluorouracil is the mainstay of chemotherapy for colorectal cancer. Previously, we have demonstrated that high glucose diminishes the cytotoxicity of 5-fluorouracil by promoting cell cycle progression. The synergistic impact of rosiglitazone on 5-fluorouracil-induced apoptosis was further investigated in this study. Besides control cell lines (CCD-18Co), two human colonic carcinoma cell lines (HCT 116 and HT 29) were exposed to different treatments containing 5-fluorouracil, rosiglitazone or 5-fluorouracil/rosiglitazone combination under normal glucose (5.5 mM) and high-glucose (25 mM) conditions. The cellular oxidative stress level was evaluated with biomarkers of nitric oxide, advanced oxidation protein products, and reduced glutathione. The cell apoptosis was assessed using flow cytometry technique. High glucose caused the production of reduced glutathione in HCT 116 and HT 29 cells. Correspondingly, high glucose suppressed the apoptotic effect of 5-fluorouracil and rosiglitazone. As compared to 5-fluorouracil alone (2 µg/mL), addition of rosiglitazone significantly enhanced the apoptosis (increment rate of 5-20%) in a dose-dependent manner at normal glucose and high glucose levels. This study indicates that high-glucose-induced reduced glutathione confers resistance to apoptosis, but it can be overcome upon treatment of 5-fluorouracil and 5-fluorouracil/rosiglitazone combination. Rosiglitazone may be a promising antidiabetic drug to reduce the chemotherapeutic dose of 5-fluorouracil for colorectal cancer complicated with hyperglycemia.

2-(Thienothiazolylimino)-1,3-thiazolidin-4-ones inhibit cell division cycle 25 A phosphatase

Cell division cycle dual phosphatases (CDC25) are essential enzymes that regulate cell progression in cell cycle. Three isoforms exist as CDC25A, B and C. Over-expression of each CDC25 enzyme is found in cancers of diverse origins. Thiazolidinone derivatives have been reported to display anti-proliferative activities, bactericidal activities and to reduce inflammation process. New 2-(thienothiazolylimino)-1,3-thiazolidin-4-ones were synthesized and evaluated as inhibitors of CDC25 phosphatase. Among the molecules tested, compound 6 inhibited CDC25A with an IC50 estimated at 6.2±1.0μM. The binding of thiazolidinone derivative 6 onto CDC25A protein was reversible. In cellulo, compound 6 treatment led to MCF7 and MDA-MB-231 cell growth arrest. To our knowledge, it is the first time that such 4-thiazolidinone derivatives are characterized as CDC25 potential inhibitor.

Downregulation of Nrf2 promotes radiation-induced apoptosis through Nrf2 mediated Notch signaling in non-small cell lung cancer cells

The nuclear factor erythroid-2-related factor 2 (Nrf2) is a crucial regulator of the cellular antioxidant system. Nrf2 is often constitutively activated in non-small cell lung cancer (NSCLC) cell lines, which promotes cytoprotection against oxidative stress and xenobiotics. Notch1 signaling is critically implicated in cell fate determination. It has been reported that Nf2 strongly regulates Notch1 activity. However, the role of Nrf2 mediated Notch1 signaling in response to ionizing radiation (IR) remains elusive. We report that knockdown of Nrf2 promotes radiation-induced apoptosis through Nrf2 mediated Notch1 signaling in NSCLC cells. IR activated Nrf2 in a dose-dependent manner and the expression of Nrf2 was significantly elevated at 4 h after exposure. RNAi-mediated reduction of Nrf2 significantly increased endogenous ROS levels, and decreased the expression of glutamate cysteine ligase catalytic subunit (GCLC), heme oxygenase-1 (HO-1) and NAD (P) H quinine oxidoreductase-1 (NQO1) in irradiated cells. Furthermore, decrease in Nrf2 expression significantly dampened Notch1 expression following ionizing radiation exposure, and potentiated IR-induced cellular apoptosis. These results demonstrated that Nrf2 could be activated by ionizing radiation, knockdown of Nrf2 could promote radiation induced apoptosis and Nrf2-mediated Notch signaling is an important determinant in radioresistance of lung cancer cells.

Expression of LC3, LAMP2, KEAP1 and NRF2 in Salivary Adenoid Cystic Carcinoma

Salivary Adenoid Cystic Carcinoma (SACC) is a tumor characterized by inevitable local progression and terminal hematogenous metastasis. This study aimed to investigate the expression of LC3, LAMP2, KEAP1 and NRF2 in SACC. Human salivary gland tissue microarray which contains 74 SACC, 12 pleomorphic adenoma and 18 normal salivary gland specimens. High expression of LC3, LAMP2, KEAP1 and NRF2 were found in SACC patients, and LC3, LAMP2, KEAP1 and NRF2 expression were significantly higher in SACC than as compared with pleomorphic adenoma and (or) normal salivary gland. The expression of NRF2 was correlated with pathological type of human SACC (P < 0.05). Moreover, the high-expression of KEAP1 had significant correlations with LC3 (P < 0.001, R = 0.3195), and LAMP2 (P < 0.001, R = 0.3346) and NRF2 (P < 0.05, R = 0.2246) by using the Pearson correlation coefficient test. Our findings demonstrated that up-regulation of LC3, LAMP2, KEAP1 and NRF2 were associated with carcinogenesis and progression of SACC patients, suggesting that they may be useful molecular targets in salivary adenoid cystic carcinoma.

Integrated analysis identifies interaction patterns between small molecules and pathways

Previous studies have indicated that the downstream proteins in a key pathway can be potential drug targets and that the pathway can play an important role in the action of drugs. So pathways could be considered as targets of small molecules. A link map between small molecules and pathways was constructed using gene expression profile, pathways, and gene expression of cancer cell line intervened by small molecules and then we analysed the topological characteristics of the link map. Three link patterns were identified based on different drug discovery implications for breast, liver, and lung cancer. Furthermore, molecules that significantly targeted the same pathways tended to treat the same diseases. These results can provide a valuable reference for identifying drug candidates and targets in molecularly targeted therapy.