bims-istrec Biomed News
on Integrated stress response in cancer
Issue of 2022‒05‒29
ten papers selected by
Vincenzo Ciminale’s Lab
Istituto Oncologico Veneto

  1. Front Pharmacol. 2022 ;13 904701
      Fluoxetine, one of the latest clinical antidepressants, is reported to have the anti-proliferative effect on cancer cells via immune-related pathways. However, the mechanism is still not known. This study mainly focused on the discovery of the molecular basis of the inhibitory effect of fluoxetine in lung cancer. The specific anti-proliferation effect and autophagy induced by fluoxetine on lung cancer cell were shown in CCK8 and immunofluorescence. The RNA sequence hinted that the endoplasmic reticulum (ER) stress-related protein and mTOR pathway were enriched after fluoxetine treatment. Western blot results revealed that the ER stress pathway was activated by fluoxetine, including PERK, ATF4, and CHOP, while the AKT/mTOR pathway was inhibited. In addition, the transfection of ATF4 siRNA further discovered that ER stress participated in the inhibition of AKT/mTOR pathway and the induction of anti-proliferation and autophagy in the fluoxetine-treated cells. More importantly, fluoxetine was demonstrated to play cytotoxic activity in cancer cells without affecting normal cells. Our results showed that fluoxetine triggered the ATF4-AKT-mTOR signaling pathway to induce cell cycle arrest and autophagy restraining cancer cells' growth in lung cancer. This study found fluoxetine unaffected the proliferation of normal lung epithelial cells, providing safe clinical therapeutic strategies for lung cancer patients with depression.
    Keywords:  ATF4-AKT-mTOR signaling pathway; autophagy; endoplasmic reticulum stress; fluoxetine; non-small cell lung cancer
  2. Int J Mol Sci. 2022 May 17. pii: 5624. [Epub ahead of print]23(10):
      Crassolide, a cembranoid diterpene extracted from the soft coral Lobophytum crissum, has been proven to possess antioxidant and immunomodulatory properties. In the present study, we assessed the anticancer effects of crassolide on human H460 non-small-cell lung cancer (NSCLC) cells. We found that crassolide exerted cytotoxic effects on H460 cancer cells in vitro, inducing G2/M phase arrest and apoptosis. In addition, in H460 cells exposed to crassolide, the expression of the autophagy-related proteins LC3-II and beclin was increased, while the expression of p62 was decreased. Moreover, inhibiting autophagy with chloroquine (CQ) suppressed the crassolide-induced G2/M arrest and apoptosis of H460 cells. Moreover, we also found that crassolide induced endoplasmic reticulum (ER) stress in lung cancer cells by increasing the expression of ER stress marker proteins and that the crassolide-induced G2/M arrest, apoptosis, and autophagy were markedly attenuated by the ER stress inhibitor 4-phenylbutyric acid (4-PBA). Furthermore, we found that crassolide promoted reactive oxygen species (ROS) production by H460 cells and that the ROS inhibitor N-acetylcysteine (NAC) decreased the crassolide-induced ER stress, G2/M arrest, apoptosis, and autophagy. In conclusion, our findings show that crassolide inhibits NSCLC cell malignant biological behaviors for the first time, suggesting that this effect may be mechanistically achieved by inducing G2/M arrest, apoptosis, and autophagy through ROS accumulation, which activates the ER stress pathway. As a result of our findings, we now have a better understanding of the molecular mechanism underlying the anticancer effect of crassolide, and we believe crassolide might be a candidate for targeted cancer therapy.
    Keywords:  ER stress; apoptosis; autophagy; cell cycle; crassolide; lung cancer; reactive oxygen species; soft coral
  3. Bioengineered. 2022 May;13(5): 12888-12898
      The mitogen-activated protein kinase kinase 5 (MEK5)/extracellular signal-regulated kinase 5 (ERK5) axis has been reported to promote tumorigenesis in breast cancer (BC). Therefore, targeting the MEK5/ERK5 axis is a potential strategy against BC. BAY-885 is a novel inhibitor of ERK5; however, to date, its anti-tumor effects in BC have not been investigated. This study aimed to assess the anti-tumor effects of BAY-885 in BC and identify its underlying mechanisms of action. Unlike other ERK5 inhibitors, which frequently failed to mimic ERK5 genetic ablation phenotypes, the BAY-885 treatment effectively recapitulated ERK5 depletion effects in BC cells. Results revealed that BAY-885 affected the viability and induced apoptosis in BC cells. Moreover, the BAY-885-mediated downregulation of myeloid cell leukemia-1 (Mcl-1) and upregulation of Bim were dependent on ERK5 inhibition. Furthermore, BAY-885 triggered activation of endoplasmic reticulum (ER) stress, which further led to the upregulation of Bim and downregulation of Mcl-1. ER stress was induced in an ERK5 inhibition-dependent manner. These findings suggested that BAY-885 induced apoptosis in BC cells via ER stress/Mcl-1/Bim axis, suggesting that BAY-885 may serve as a therapeutic agent for BC.
    Keywords:  BAY-885; Breast cancer; ERK5; mcl-1
  4. Int Immunopharmacol. 2022 May 19. pii: S1567-5769(22)00349-6. [Epub ahead of print]108 108865
      Colorectal cancer is the third leading cause of cancer incidence and mortality in the United States. Cannabidiol (CBD), the second most abundant phytocannabinoid in Cannabis sativa, has potential use in cancer treatment on the basis of many studies showing its anti-cancer activity in diverse types of cancer, including colon cancer. However, its mechanism of action is not yet fully understood. In the current study, we observed CBD to repress viability of different human colorectal cancer cells in a dose-dependent manner. CBD treatment led to G1-phase cell cycle arrest and an increased sub-G1 population (apoptotic cells); it also downregulated protein expression of cyclin D1, cyclin D3, cyclin-dependent kinase 2 (CDK2), CDK4, and CDK6. CBD further increased caspase 3/7 activity and cleaved poly(ADP-ribose) polymerase, and elevated expression of endoplasmic reticulum (ER) stress proteins including binding immunoglobulin protein (BiP), inositol-requiring enzyme 1α (IRE1α), phosphorylated eukaryotic initiation factor 2α (eIF2α), activating transcription factor 3 (ATF3), and ATF4. We found that CBD repressed cell viability and induced apoptotic cell death through a mechanism dependent on cannabinoid receptor type 2 (CB2), but not on CB1, transient receptor potential vanilloid, or peroxisome proliferator-activated receptor gamma. Anti-proliferative activity was also observed for other non-psychoactive cannabinoid derivatives including cannabidivarin (CBDV), cannabigerol (CBG), cannabicyclol (CBL), and cannabigerovarin (CBGV). Our data indicate that CBD and its derivatives could be promising agents for the prevention of human colorectal cancer.
    Keywords:  Apoptosis; Cannabidiol; Cannabinoid receptor 2; Cell growth arrest; Colorectal cancer
  5. Med Oncol. 2022 May 23. 39(5): 101
      Colon cancer is one of the most leading death-causing cancers in the world. Cisplatin has been widely used as the first-line treatment of cancer. However, its clinical application is limited by the side effects or acquired drug resistance. Hence, it is of vital clinical significance to develop novel agents that synergize with cisplatin and decrease its side effects. The aim of this study was to investigate whether Andrographolide (AP) synergistically potentiates the anti-tumor effect of cisplatin on colon cancer cells. Here, we found that AP synergizes with cisplatin in exerting anticancer activity in colon cancer cells. Further studies showed that AP potentiates cisplatin-induced endoplasmic reticulum stress and STAT3 inhibition through increasing intracellular ROS. Notably, pre-treatment of NAC, a ROS scavenger, reversed apoptosis induced by combined treatment of AP and cisplatin, while relieving the activation of endoplasmic reticulum stress as well as STAT3 inhibition. These findings indicated that ROS plays a pivotal role in mediating synergistic anticancer effects of AP and cisplatin on colon cancer cells. Overall, this study presents a potential new therapeutic strategy for the treatment of colon cancer.
    Keywords:  Andrographolide; Cisplatin; Endoplasmic reticulum stress; ROS; STAT3
  6. Cancers (Basel). 2022 May 20. pii: 2528. [Epub ahead of print]14(10):
      Hepatocellular carcinoma (HCC), the most common type of liver cancer, is the leading cause of cancer-related mortality worldwide. Chemotherapy is the major treatment modality for advanced or unresectable HCC; unfortunately, chemoresistance results in a poor prognosis for HCC patients. Exogenous ceramide, a sphingolipid, has been well documented to exert anticancer effects. However, recent reports suggest that sphingolipid metabolism in ceramide-resistant cancer cells favors the conversion of exogenous ceramides to prosurvival sphingolipids, conferring ceramide resistance to cancer cells. However, the mechanism underlying ceramide resistance remains unclear. We previously demonstrated that diTFPP, a novel phenoxyphenol compound, enhances the anti-HCC effect of C2-ceramide. Here, we further clarified that treatment with C2-ceramide alone increases the protein level of CERS2, which modulates sphingolipid metabolism to favor the conversion of C2-ceramide to prosurvival sphingolipids in HCC cells, thus activating the unfolded protein response (UPR), which further initiates autophagy and the reversible senescence-like phenotype (SLP), ultimately contributing to C2-ceramide resistance in these cells. However, cotreatment with diTFPP and ceramide downregulated the protein level of CERS2 and increased oxidative and endoplasmic reticulum (ER) stress. Furthermore, insufficient LAMP2 glycosylation induced by diTFPP/ceramide cotreatment may cause the failure of autophagosome-lysosome fusion, eventually lowering the threshold for triggering cell death in response to C2-ceramide. Our study may shed light on the mechanism of ceramide resistance and help in the development of adjuvants for ceramide-based cancer therapeutics.
    Keywords:  LAMP2 glycosylation; autophagic stress; ceramide; diTFPP; endoplasmic reticulum (ER) stress; hepatocellular carcinoma (HCC); oxidative stress; phenoxyphenol compound; sphingolipid metabolism
  7. Cancers (Basel). 2022 May 20. pii: 2526. [Epub ahead of print]14(10):
      Synthesis, folding, and structural maturation of proteins occur in the endoplasmic reticulum (ER). Accumulation of misfolded or unfolded proteins in the ER lumen contributes to the induction of ER stress and activation of the unfolded protein response (UPR) signaling pathway. Under ER stress, the UPR tries to maintain cellular homeostasis through different pathways, including the inositol-requiring enzyme 1 alpha (IRE1α)-dependent ones. IRE1α is located in an ER membrane, and it is evolutionarily the oldest UPR sensor. Activation of IRE1α via ER stress triggers the formation of the spliced form of XBP1 (XBP1s), which has been linked to a pro-survival effect in cancer cells. The role of IRE1α is critical for blood cancer cells, and it was found that the levels of IRE1α and XBP1s are elevated in various hematological malignancies. This review paper is focused on summarizing the latest knowledge about the role of IRE1α and on the assessment of the potential utility of IRE1α inhibitors in blood cancers.
    Keywords:  X-box-binding protein 1 (XBP1); blood cancer; endoplasmic reticulum stress; inositol-requiring enzyme 1 alpha (IRE1α); leukemia; lymphoma; multiple myeloma; unfolded protein response
  8. BMC Neurol. 2022 May 25. 22(1): 192
      BACKGROUND: Glioma is the most common brain tumor in adults and is characterized by a short survival time and high resistance to chemotherapy. It is imperative to determine the prognosis and therapy-related targets for glioma. Endoplasmic reticulum stress (ERS), as an adaptive protective mechanism, indicates the unfolded protein response (UPR) to determine cell survival and affects chemotherapy sensitivity, which is related to the prognosis of glioma.METHODS: Our research used the TCGA database as the training group and the CGGA database as the testing group. Lasso regression and Cox analysis were performed to construct an ERS signature-based risk score model in glioma. Three methods (time-dependent receiver operating characteristic analysis and multivariate and univariate Cox regression analysis) were applied to assess the independent prognostic effect of texture parameters. Consensus clustering was used to classify the two clusters. In addition, functional and immune analyses were performed to assess the malignant process and immune microenvironment. Immunotherapy and anticancer drug response prediction were adopted to evaluate immune checkpoint and chemotherapy sensitivity.
    RESULTS: The results revealed that the 7-gene signature strongly predicts glioma prognosis. The two clusters have markedly distinct molecular and prognostic features. The validation group result revealed that the signature has exceptional repeatability and certainty. Functional analysis showed that the ERS-related gene signature was closely associated with the malignant process and prognosis of tumors. Immune analysis indicated that the ERS-related gene signature is strongly related to immune infiltration. Immunotherapy and anticancer drug response prediction indicated that the ERS-related gene signature is positively correlated with immune checkpoint and chemotherapy sensitivity.
    CONCLUSIONS: Collectively, the ERS-related risk model can provide a novel signature to predict glioma prognosis and treatment.
    Keywords:  Endoplasmic reticulum stress; Function; Gene signature; Glioma; Immune therapy; Prognosis
  9. Anticancer Agents Med Chem. 2022 May 23.
      BACKGROUND: Marine actinobacteria have proven to be a remarkable source of bioactive metabolites.METHODS: The present study focused on the isolation of anticancer metabolites from marine actinobacteria. Streptomyces sp. VITGAP173 was found to have promising anticancer activity against breast cancer cell lines (MCF-7).
    RESULTS: Bioassay-guided fractionation was followed to identify the bioactive metabolites from crude ethyl acetate extract of VITGAP173, which yielded four fractions. Among the four fractions, fraction B exhibited the highest cytotoxic activity against MCF-7 cell lines. Further structural characterization of the fraction was done by FTIR and NMR spectroscopy. The fraction-2 induced cytotoxicity against MCF-7 cell lines and the half maximal inhibition (IC50) value was calculated as 4.7μg/ml. To elucidate the possible mechanism of cell death, MCF-7 cells were treated with fraction-2 for 24 hours and the morphological changes were examined using acridine orange - ethidium bromide (AO/EB) staining. The fraction also increased the reactive oxygen species (ROS) generation (Flow cytometry, DCFH-DA). The molecular mechanism of fraction-induced cell death was analysed by real-time PCR, which revealed that the fraction promotes apoptosis through the CHOP-ATF-4 pathway which is involved in ER stress signalling.
    CONCLUSION: The present findings suggest the apoptosis inducing potential of fraction-2 in breast cancer therapy.
    Keywords:  ER stress; Mangrove; actinobacteria; apoptosis; bioactive fraction; cytotoxic
  10. Biomedicines. 2022 May 10. pii: 1098. [Epub ahead of print]10(5):
      The 78 kDa glucose-regulated protein (GRP78) is considered an endoplasmic reticulum (ER)-resident molecular chaperone that plays a crucial role in protein folding homeostasis by regulating the unfolded protein response (UPR) and inducing numerous proapoptotic and autophagic pathways within the eukaryotic cell. However, in cancer cells, GRP78 has also been shown to migrate from the ER lumen to the cell surface, playing a role in several cellular pathways that promote tumor growth and cancer cell progression. There is another insidious consequence elicited by cell surface GRP78 (csGRP78) on cancer cells: the accumulation of csGRP78 represents a novel neoantigen leading to the production of anti-GRP78 autoantibodies that can bind csGRP78 and further amplify these cellular pathways to enhance cell growth and mitigate apoptotic cell death. This review examines the current body of literature that delineates the mechanisms by which ER-resident GRP78 localizes to the cell surface and its consequences, as well as potential therapeutics that target csGRP78 and block its interaction with anti-GRP78 autoantibodies, thereby inhibiting further amplification of cancer cell progression.
    Keywords:  GRP78; autoantibody; cancer