Notch1 inhibition enhances DNA damage induced by cisplatin in cervical cancer

Silencing DTX3L Inhibits the Progression of Cervical Carcinoma by Regulating PI3K/AKT/mTOR Signaling Pathway

Cervical carcinoma (CC) is the second most prevalent gynecologic cancer in females across the world. To obtain a better understanding of the mechanisms underlying the development of CC, high-resolution label-free mass spectrometry was performed on CC and adjacent normal tissues from eight patients. A total of 2631 proteins were identified, and 46 significant differently expressed proteins (DEPs) were found between CC and normal tissues (p < 0.01, fold change >10 or <0.1). Ingenuity pathway analysis revealed that the majority of the proteins were involved in the regulation of eIF4 and p70S6K signaling and mTOR signaling. Among 46 DEPs, Integrinβ6 (ITGB6), PPP1CB, TMPO, PTGES3 (P23) and DTX3L were significantly upregulated, while Desmin (DES) was significantly downregulated in CC tissues compared with the adjacent normal tissues. In in vivo and in vitro experiments, DTX3L knockdown suppressed CC cell proliferation, migration, invasion and xenograft tumorigenesis, and enhanced cell apoptosis. Combination of silencing DTX3L and cisplatin treatment induced higher apoptosis percentage compared to cisplatin treatment alone. Moreover, DTX3L silencing inhibited the PI3K/AKT/mTOR signal pathway. Thus, our results suggested DTX3L could regulate CC progression through the PI3K/AKT/mTOR signal pathway and is potentially a novel biomarker and therapeutic target for CC.

Investigating the molecular mechanisms of glyoxal-induced cytotoxicity in human embryonic kidney cells: Insights from network toxicology and cell biology experiments

Glyoxal, a reactive carbonyl species, can be generated both endogenously (glucose metabolism) and exogenously (cigarette smoke and food system). Increasing evidence demonstrates that glyoxal exacerbates the development and progression of diabetic nephropathy, but the underlying mechanisms of glyoxal toxicity to human embryonic kidney (HEK293) cells remain unclear. In this work, the molecular mechanisms of glyoxal-induced cytotoxicity in HEK293 cells were explored with network toxicology and cell biology experiments. Network toxicology results showed that oxidative stress and advanced glycation end products (AGEs)/RAGE signaling pathways played a crucial role in glyoxal toxicity. Next, further validation was performed at the cellular level. Glyoxal activated the AGEs-RAGE signaling pathway, caused the increase of cellular ROS, and activated the p38MAPK and JNK signaling pathways, causing cellular oxidative stress. Furthermore, glyoxal caused the activation of the NF-κB signaling pathway and increased the expression of TGF-β1, indicating that glyoxal caused cellular inflammation. Moreover, glyoxal caused cellular DNA damage accompanied by the activation of DNA damage response pathways. Finally, the mitochondrial apoptosis pathway was activated. The results that obtained in cell biology were consistent with network toxicology, which corroborated each other and together indicated that glyoxal induced HEK293 cells damage via the process of oxidative stress, the AGEs-RAGE pathway, and their associated signaling pathways. This study provides the experimental basis for the cytotoxicity of glyoxal on HEK293 cells.

Period circadian regulator 2 suppresses drug resistance to cisplatin by PI3K/AKT pathway and improves chronochemotherapeutic efficacy in cervical cancer

OBJECTIVE

Chronotherapy, a promising therapy, may build up the chemotherapy efficacy through thinking about timing of therapy. Here, we observed the roles of period circadian regulator 2 (PER2) on cervical cancer progression and the therapeutic efficacy of cisplatin (DDP) based on the circadian rhythm of PER2.

METHODS

When Hela/DDP and SiHa/DDP transfected with pcDNA3.1-PER2 and/or treated with human epidermal growth factor (hEGF), viability, apoptosis, migration, and nuclear translocation of NF-κB p65 were detected by CCK-8, flow cytometry, transwell, immunofluorescence and western blot. Furthermore, the expression of circadian rhythm regulators, multidrug resistance, and epithelial-mesenchymal transition (EMT) proteins was detected by western blot. Hela/DDP cells-induced tumor formation in nude mice was constructed. The expression of PER2 was measured at different time point by RT-qPCR. Cisplatin was separately injected into mice with cervical cancer at the highest and lowest expression of PER2. After 5 weeks, tumor volume was measured and tumor proliferation was assessed by immunohistochemistry.

RESULTS

Overexpression of PER2 significantly reduced proliferative and migrated capacities and nuclear translocation of NF-κB p65 as well as enhanced apoptosis in Hela/DDP and SiHa/DDP cells. Meanwhile, its overexpression elevated the expression of circadian rhythm regulators as well as lowered the expression of multidrug resistance proteins and EMT pathway activation by suppressing PI3K/AKT pathway. PER2 was rhythmically expressed in cervical cancer tissues. Compared to cisplatin treatment at the lowest expression of PER2, tumor growth and proliferation of tumor cells were distinctly suppressed in mice treated with cisplatin at the highest expression of PER2.

CONCLUSION

Our findings confirmed the circadian rhythm of PER2 in cervical cancer and its overexpression restrained the resistance to cisplatin in cervical cancer by PI3K/AKT pathway. It may improve cisplatin efficacy through considering the circadian rhythm of PER2.

Potential mechanisms of methylglyoxal-induced human embryonic kidney cells damage: Regulation of oxidative stress, DNA damage, and apoptosis

Methylglyoxal (MGO) is a reactive carbonyl species that can cause cellular damage and is closely related to kidney disease, especially diabetic nephropathy. The toxic effect of MGO (0.5, 1, and 2 mM) on human embryonic kidney (HEK293) cells and its underlying mechanism were explored in this study. Cell viability, apoptosis and the signaling pathways were measured with MTT, fluorescent staining and western blot experiments, the results showed that MGO could induce oxidative stress and cell inflammation, the level of reactive oxygen species (ROS) increased, and p38MAPK, JNK and NF-κB signaling pathways were activated. Meanwhile, MGO also induced DNA damage. The expression of DNA oxidative damage marker 8-hydroxy-2'-deoxyguanosine (8-OHdG) increased, the expression of double-strand break marker γH2AX increased significantly, and ATM/Chk2/p53 DNA damage response signaling pathway was activated. Furthermore, the expression of the receptor for advanced glycation end products (RAGE) also increased. Finally, mitochondrial membrane potential (MMP) decreased, fluorescence intensity of Hoechst33258 increased, and the protein expression ratio of Bax/Bcl-2 increased significantly after the treatment of MGO. These results demonstrated that MGO might induce HEK293 cells damage by regulating oxidative stress, inflammation, DNA damage, and cell apoptosis, which revealed the specific mechanism of MGO-induced damage to HEK293 cells.

Up-regulation of miR-34c-5p inhibits nasopharyngeal carcinoma cells by mediating NOTCH1.Biosci Rep. 2020;40. [PMID: 32458967 DOI: 10.1042/BSR20200302]

OBJECTIVE

To explore the correlation between miR-34c-5p and NOTCH1 in nasopharyngeal carcinoma (NPC).

MATERIALS AND METHODS

qPCR was employed to quantify miR-34c-5p and NOTCH1 mRNA in NPC, and Western blot to detect NOTCH1. MiR-34c-5p mimics/inhibitor and NOTCH1 siRNA were constructed to analyze the role of miR-34c-5p/NOTCH1 on the biological function of NPC cells.

RESULTS

NPC cells showed lower miR-34c-5p expression and higher NOTCH1 expression than normal cells, and up-regulating miR-34c-5p or inhibiting NOTCH1 could strongly suppress the epithelial-mesenchymal transition (EMT), proliferation, invasion and migration of NPC cells, and induce apoptosis in them. Up-regulating miR-34c-5p could inhibit NOTCH1, and miR-34c-5p was negatively correlated with NOTCH1. Rescue experiment results revealed that NOTCH1 up-regulation could counteract the changes of cell process induced by increased miR-34c-5p.

CONCLUSION

MiR-34c-5p inhibits the growth of NPC by down-regulating NOTCH1, so up-regulating miR-34c-5p or down-regulating NOTCH1 may become the potential direction of NPC treatment.

Theasaponin E1 Inhibits Platinum-Resistant Ovarian Cancer Cells through Activating Apoptosis and Suppressing Angiogenesis

Novel therapeutic strategies for ovarian cancer treatment are in critical need due to the chemoresistance and adverse side effects of platinum-based chemotherapy. Theasaponin E₁ (TSE1) is an oleanane-type saponin from Camellia sinensis seeds. Its apoptosis-inducing, cell cycle arresting and antiangiogenesis activities against platinum-resistant ovarian cancer cells were elucidated in vitro and using the chicken chorioallantoic membrane (CAM) assay. The results showed that TSE1 had more potent cell growth inhibitory effects on ovarian cancer OVCAR-3 and A2780/CP70 cells than cisplatin and was lower in cytotoxicity to normal ovarian IOSE-364 cells. TSE1 significantly induced OVCAR-3 cell apoptosis via the intrinsic and extrinsic apoptotic pathways, slightly arresting cell cycle at the G2/M phase, and obviously inhibited OVCAR-3 cell migration and angiogenesis with reducing the protein secretion and expression of vascular endothelial growth factor (VEGF). Western bolt assay showed that Serine/threonine Kinase (Akt) signaling related proteins including Ataxia telangiectasia mutated kinase (ATM), Phosphatase and tensin homolog (PTEN), Akt, Mammalian target of rapamycin (mTOR), Ribosome S6 protein kinase (p70S6K) and e IF4E-binding protein 1(4E-BP1) were regulated, and Hypoxia inducible factor-1α (HIF-1α) protein expression was decreased by TSE1 in OVCAR-3 cells. Moreover, TSE1 treatment potently downregulated protein expression of the Notch ligands including Delta-like protein 4 (Dll4) and Jagged1, and reduced the protein level of the intracellular domain (NICD) of Notch1. Combination treatment of TSE1 with the Notch1 signaling inhibitor tert-butyl (2S)-2-[[(2S)-2-[[2-(3,5-difluorophenyl)acetyl]amino]propanoyl]amino]-2-phenylacetate (DAPT), or the Akt signaling inhibitor wortmannin, showed a stronger inhibition toward HIF-1α activation compared with single compound treatment. Taken together, TSE1 might be a potential candidate compound for improving platinum-resistant ovarian cancer treatment via Dll4/Jagged1-Notch1-Akt-HIF-1α axis.

Eupalinolide J induces apoptosis, cell cycle arrest, mitochondrial membrane potential disruption and DNA damage in human prostate cancer cells

Eupalinolide J (EJ) is a new sesquiterpene lactone isolated from Eupatorium lindleyanum DC. In the present study, we investigated the anti-cancer activity of EJ on cell proliferation in human prostate cancer cells. The MTT results indicated that EJ showed marked anti-proliferative activity in PC-3 and DU-145 cells in a dose- and time-dependent manner. DAPI staining analysis demonstrated that this effect was mediated by induction of cell apoptosis. Flow cytometric analysis indicated a significant increase in apoptotic cells, cell cycle arrest at G0/G1 phase and disruption of mitochondrial membrane potential (MMP) after EJ treatment. Meanwhile, the activation of caspase-3 and caspase-9 was visibly observed. Furthermore, our results demonstrated that the expression levels of γH2AX, p-Chk1 and p-Chk2 were significantly up-regulated, suggesting the induction of DNA damage responses in EJ-treated prostate cancer cells. The above results indicated that EJ exhibited effective anti-cancer activity in vitro. It could be a promising candidate agent for the clinical treatment of prostate cancer.

Phosphorylation-dependent regulation of the NOTCH1 intracellular domain by dual-specificity tyrosine-regulated kinase 2

NOTCH proteins constitute a receptor family with a widely conserved role in cell cycle, growing and development regulation. NOTCH1, the best characterised member of this family, regulates the expression of key genes in cell growth and angiogenesis, playing an essential role in cancer development. These observations provide a relevant rationale to propose the inhibition of the intracellular domain of NOTCH1 (Notch1-IC) as a strategy for treating various types of cancer. Notch1-IC stability is mainly controlled by post-translational modifications. FBXW7 ubiquitin E3 ligase-mediated degradation is considered one of the most relevant, being the previous phosphorylation at Thr-2512 residue required. In the present study, we describe for the first time a new regulation mechanism of the NOTCH1 signalling pathway mediated by DYRK2. We demonstrate that DYRK2 phosphorylates Notch1-IC in response to chemotherapeutic agents and facilitates its proteasomal degradation by FBXW7 ubiquitin ligase through a Thr-2512 phosphorylation-dependent mechanism. We show that DYRK2 regulation by chemotherapeutic agents has a relevant effect on the viability, motility and invasion capacity of cancer cells expressing NOTCH1. In summary, we reveal a novel mechanism of regulation for NOTCH1 which might help us to better understand its role in cancer biology.

Identification of Deleterious NOTCH Mutation as Novel Predictor to Efficacious Immunotherapy in NSCLC

PURPOSE

NOTCH signaling is associated with tumorigenesis, mutagenesis, and immune tolerance in non-small cell lung cancer (NSCLC), indicating its association with the clinical benefit of immune checkpoint inhibitors (ICI). We hypothesized that NOTCH mutation in NSCLC might be a robust predictor of immunotherapeutic efficacy.

EXPERIMENTAL DESIGN

Multiple-dimensional data including genomic, transcriptomic, and clinical data from cohorts of NSCLC internal and public cohorts involving immunotherapeutic patients were analyzed. Polymorphism Phenotyping v2 (PolyPhen-2) system was performed to determine deleterious NOTCH mutation (del-NOTCH ^mut). Further investigation on molecular mechanism was performed in The Cancer Genome Atlas (TCGA) data via CIBERSORT and gene set enrichment analysis.

RESULTS

Our 3DMed cohort (n = 58) and other four cohorts (Rizvi, POPLAR/OAK, Van Allen, and MSKCC; n = 1,499) uncovered marked correlation between NOTCH1/2/3 mutation and better ICI outcomes in EGFR/ALK ^WT population, including objective response rate (2.20-fold, P = 0.001), progression-free survival [HR, 0.61; 95% confidence interval (CI), 0.46-0.81; P = 0.001], and overall survival (HR, 0.56; 95% CI, 0.32-0.96; P = 0.035). Del-NOTCH ^mut exhibited better predictive function than non-deleterious NOTCH mutation, potentially via greater transcription of genes related to DNA damage response and immune activation. Del-NOTCH ^mut was not linked with prognosis in TCGA cohorts and chemotherapeutic response, but was independently associated with immunotherapeutic benefit, delineating the predictive, but not prognostic, utility of del-NOTCH ^mut.

CONCLUSIONS

This work distinguishes del-NOTCH ^mut as a potential predictor to favorable ICI response in NSCLC, highlighting the importance of genomic profiling in immunotherapy. More importantly, our results unravel a possibility of personalized combination immunotherapy as adding NOTCH inhibitor to ICI regimen in NSCLC, for the optimization of ICI treatment in clinical practice.

Inhibition of TRIM32 Induced by miR-519d Increases the Sensitivity of Colorectal Cancer Cells to Cisplatin

BACKGROUND

Colorectal cancer is a leading cause of cancer-related death in the world. Despite cisplatin is a commonly used chemotherapeutic drug for the colorectal cancer treatment, resistance of cancer cells to cisplatin restricts its clinical efficacy. It is important to explore the potential mechanisms and take strategies to sensitize colorectal cancer cells to cisplatin treatment.

METHODS

Differences of TRIM32 and miR-519d expression between colorectal cancer cells and human normal colon epithelial cells were evaluated by qRT-PCR and Western blot assays. Cytotoxicity of cisplatin against colorectal cancer cells was tested by CCK-8 assay. Generation of reactive oxygen species (ROS), mitochondrial membrane potential and apoptosis was measured by flow cytometry. Dual-luciferase reporter assay was used to validate the association between miR-519d and TRIM32.

RESULTS

Significant increase of TRIM32 expression in colorectal cancer tissues and cell lines was observed. TRIM32 negatively regulated the cisplatin sensitivity in colorectal cancer cells. Mechanically, overexpression of TRIM32 was induced by decrease of miR-519d. Exogenous miR-519d can inhibit the expression of TRIM32 and thus promoted the cisplatin-induced apoptosis through the mitochondrial pathway.

CONCLUSION

Overexpression of TRIM32 was induced by the absence of miR-519d in colorectal cancer. MiR-519d can be used as a sensitizer during the cisplatin-based chemotherapy of colorectal cancer.

Shp2 expression is upregulated in cervical cancer, and Shp2 contributes to cell growth and migration and reduces sensitivity to cisplatin in cervical cancer cells

Src homology phosphotyrosine phosphatase 2 (Shp2) has been found to be overexpressed in cervical cancer tissues. However, the influence of Shp2 on the biological behavior and sensitivity to cisplatin of cervical cancer cells remains unclear. We aimed to assess Shp2 expression in cervical tissues and cell lines and to detect the influence of Shp2 knockdown and overexpression on the biological behavior and sensitivity to cisplatin in cervical cancer cells. We found that Shp2 expression was significantly upregulated in cervical cancer tissues and cell lines, and Shp2 overexpression was associated with lymph node metastasis and a high human papillomavirus (HPV) DNA load. Shp2 knockdown inhibited cell growth and migration and enhanced sensitivity to cisplatin in the HeLa and SiHa cervical cancer cell lines. In contrast, Shp2 overexpression had the opposite effects. These tumor-promoting effects of Shp2 may be partly related to Akt signaling. In conclusion, Shp2 is involved in the occurrence and development of cervical cancer and may confer cisplatin resistance in cervical cancer. Shp2 blockade may be a new strategy for cervical cancer treatment.