bims-istrec Biomed News
on Integrated stress response in cancer
Issue of 2022‒04‒24
nine papers selected by
Vincenzo Ciminale’s Lab
Istituto Oncologico Veneto

  1. Bioengineered. 2022 Apr;13(4): 10564-10577
      Endoplasmic reticulum stress (ER stress) is a double-edged sword in the occurrence and development of malignant cancer. The aim of this study was to explore the roles of ER stress in metastasis and epithelial-mesenchymal transitionin triple-negative breast cancer (TNBC) and potential mechanisms. In this study, 4-PBA was administrated to inhibit the ER stress. Cell viability was evaluated using a cell counting kit-8 assay. Cell migration and invasion were identified by wound healing and transwell assay, respectively. Levels of MMP2 and MMP9 were measured by enzyme-linked immunosorbent assay and immunohistochemical staining. Western blot assay was used to assess the levels of ER stress-related proteins, Syndecan-1 (SDC-1)/Syntenin-1 (SDCBP-1)/SRY-related HMG-box 4 (SOX4) signaling and Wnt/β-catenin signaling. Moreover, a xenograft mice model was conducted to confirm the role of ER stress in TNBC. The data indicate that the ability of viability and metastasis of breast cancer cells were stronger than normal mammary epithelial cells. More aggressiveness was manifested in TNBC cells than that in non-TNBC cells. 4-PBA significantly suppressed the viability, migration, and invasion in BC cells and inhibited the SDC/SDCBP/SOX4 axis and Wnt/β-catenin signaling. Furthermore, heat shock protein A4 (HSPA4) overexpression stimulated ER stress and activated the SDC-1/SDCBP-1/SOX4 pathway and Wnt/β-catenin signaling. Animal experiments showed similar results that 4-PBA repressed tumor growth and inactivated the two pathways, while HSPA4 overexpression reversed the effects of 4-PBA. In summary, inhibition of ER stress inhibited TNBC viability, migration, and invasion by Syntenin/SOX4/Wnt/β-catenin pathway via regulation of HSPA4 in vivo and in vitro.
    Keywords:  Endoplasmic reticulum stress; HSPA4; Syntenin/SOX4; Wnt/β-catenin pathway; triple-negative breast cancer (TNBC)
  2. Molecules. 2022 Apr 12. pii: 2471. [Epub ahead of print]27(8):
      Cancer is a major health problem across the globe, and is expeditiously growing at a faster rate worldwide. The endoplasmic reticulum (ER) is a membranous cell organelle having inextricable links in cellular homeostasis. Altering ER homeostasis initiates various signaling events known as the unfolded protein response (UPR). The basic purpose of the UPR is to reinstate the homeostasis; however, a continuous UPR can stimulate pathways of cell death, such as apoptosis. As a result, there is great perturbation to target particular signaling pathways of ER stress. Flavonoids have gained significant interest as a potential anticancer agent because of their considerable role in causing cytotoxicity of the cancerous cells. Luteolin, a flavonoid isolated from natural products, is a promising phytochemical used in the treatment of cancer. The current study is designed to review the different endoplasmic reticulum stress pathways involved in the cancer, mechanistic insights of luteolin as an anticancer agent in modulating ER stress, and the available luteolin patent formulations were also highlighted. The patents were selected on the basis of pre-clinical and/or clinical trials, and established antitumor effects using patent databases of FPO IP and Espacenet. The patented formulation of luteolin studied so far has shown promising anticancer potential against different cancer cell lines. However, further research is still required to determine the molecular targets of such bioactive molecules so that they can be used as anticancer drugs.
    Keywords:  ER stress; cancer; luteolin; luteolin combating ER stress; trigger proliferation of cancerous cells
  3. Blood. 2022 Apr 20. pii: blood.2021013277. [Epub ahead of print]
      Inducing cell death by the sphingolipid ceramide is a potential anti-cancer strategy, but the underlying mechanisms remain poorly defined. Here, we show that triggering accumulation of ceramide in acute myeloid leukaemia (AML) cells by inhibition of sphingosine kinase induces an apoptotic integrated stress response (ISR) through protein kinase R-mediated activation of the master transcription factor ATF4. This leads to transcription of the BH3-only protein, Noxa, and degradation of the pro-survival Mcl-1 protein on which AML cells are highly dependent on for survival. Targeting this novel ISR pathway in combination with the Bcl-2 inhibitor venetoclax synergistically killed primary AML blasts, including those with venetoclax-resistant mutations, as well as immunophenotypic leukemic stem cells, and reduced leukemic engraftment in patient-derived AML xenografts. Collectively, these findings provide mechanistic insight into the anti-cancer effects of ceramide and pre-clinical evidence for new approaches to augment Bcl-2 inhibition in the therapy of AML and other cancers with high Mcl-1 dependency.
  4. Virus Res. 2022 Apr 14. pii: S0168-1702(22)00114-9. [Epub ahead of print] 198787
      Hepatitis B virus (HBV) infection is a major cause of hepatocellular carcinoma (HCC) worldwide. HBV X protein (HBx) is potentially the most oncogenic among HBV-encoding proteins, while HBV integration, which is frequently observed in HCC, contributes to HCC development. However, the molecular mechanism underlying HBV-induced hepatocarcinogenesis remains unclear. In this study, we identified the fusion HBx, the HBx-human fusion protein derived from HBV integrant, in Hep3B cells and investigated its role in hepatocarcinogenesis. The identified full-length fusion mRNA was 3,725 bp in length, and the fusion HBx, which consisted of 1-140 amino acids of HBx followed by 61 amino acids from the human genome, was translated from the fusion mRNA. The fusion HBx knockdown resulted in reduced cell proliferation and invasion, and loss of tumor development in nude mice. Moreover, the fusion HBx, but not wild HBx, provided anchorage-independent growth ability in soft agar although its transactivation ability was abrogated. Microarray analysis revealed that fusion HBx deregulated endoplasmic reticulum (ER) stress response by modifying ATF3, ATF4, and ATF6 transcription. Interestingly, the effects of fusion HBx on ER stress signaling pathway were similar to those of C-terminal truncated HBx, but significantly different from those of wild HBx. Our findings suggest that the fusion HBx plays a significant role in hepatocarcinogenesis by modifying ER stress response and could be an attractive target for the treatment of HBV-induced HCC.
    Keywords:  endoplasmic reticulum stress; fusion HBx; hepatitis B virus; hepatocellular carcinoma; integration
  5. Cell Death Dis. 2022 Apr 18. 13(4): 357
      In the tumor microenvironment, cancer cells experience hypoxia resulting in the accumulation of misfolded/unfolded proteins largely in the endoplasmic reticulum (ER). Consequently, ER proteotoxicity elicits unfolded protein response (UPR) as an adaptive mechanism to resolve ER stress. In addition to canonical UPR, proteotoxicity also stimulates the selective, autophagy-dependent, removal of discrete ER domains loaded with misfolded proteins to further alleviate ER stress. These mechanisms can favor cancer cell growth, metastasis, and long-term survival. Our investigations reveal that during hypoxia-induced ER stress, the ER-phagy receptor FAM134B targets damaged portions of ER into autophagosomes to restore ER homeostasis in cancer cells. Loss of FAM134B in breast cancer cells results in increased ER stress and reduced cell proliferation. Mechanistically, upon sensing hypoxia-induced proteotoxic stress, the ER chaperone BiP forms a complex with FAM134B and promotes ER-phagy. To prove the translational implication of our mechanistic findings, we identified vitexin as a pharmacological agent that disrupts FAM134B-BiP complex, inhibits ER-phagy, and potently suppresses breast cancer progression in vivo.
  6. Front Oncol. 2022 ;12 844214
      Cancer pain is an important factor affecting life quality of patients especially in the advanced stage and relieving pain is one of fundamental strategies for cancer treatment. Opioids such as morphine are the most widely used in clinics. However, they have been reported to be associated with the occurrence and development of several types of cancer. Thus, search for an opioid that has analgesic effect and can retard cancer progress simultaneously is critical for cancer management. In this study, we first examined the expression of μ and κ (MOR and KOR) in cell lines and tumor tissues of hepatocellular carcinoma (HCC), a malignant tumor with high mortality, and then compared the effects of opioid receptors-specific agonists on malignant phenotypes of HCC cells in vitro and tumor growth in an HCC xenograft mouse model. KOR and MOR were found to be highly expressed in HCC cell lines and HCC tissues. The KOR-specific agonist U50488h, oxycodone (agonist for both KOR and MOR) and the MOR-specific agonist morphine inhibited HCC cell proliferation, while only U50488h and oxycodone suppressed colony formation and migration of HCC cells. U50488h and oxycodone, but not morphine, induced HCC apoptosis. Further detection of PERK, GRP78 and CHOP revealed that PERK signaling was upregulated by treatment with U50488h, while treatment with the PERK inhibitor GSK2656157 partially reversed the promotion of apoptosis and inhibition of cell proliferation by U50488h, indicating that endoplasmic reticulum stress is associated with its suppressing effect on HCC malignant phenotypes. Similar to the in vitro results, HCC growth was significantly reduced by administration of U50488h and oxycodone, but not by morphine, in the HCC xenograft mouse model. PERK and caspase-3 in the HCC tissues were up-regulated by U50488h treatment as detected by immunohistochemistry and western blotting. Taken together, our results revealed that activation of KOR by U50488h inhibited malignant phenotypes of HCC both in vitro and in vivo, while activation of MOR by morphine did not have such effect. Because of their dual roles in the relief of pain and in the suppression of malignant phenotypes, opioids such as U50488h that act on KOR should be considered as the first choice for HCC management.
    Keywords:  PERK pathway; apoptosis; hepatocellular carcinoma; opioid agonists; opioid receptors
  7. Biomolecules. 2022 Mar 23. pii: 487. [Epub ahead of print]12(4):
      Breast cancer is an ancient disease recognized first by the Egyptians as early as 1600 BC. The first cancer-causing gene in a chicken tumor virus was found in 1970. The United States signed the National Cancer Act in 1971, authorizing federal funding for cancer research. Irrespective of multi-disciplinary approaches, diverting a great deal of public and private resources, breast cancer remains at the forefront of human diseases, affecting as many as one in eight women during their lifetime. Because of overarching challenges and changes in the breast cancer landscape, five-year disease-free survival is no longer considered adequate. The absence of a cure, and the presence of drug resistance, severe side effects, and destruction of the patient's quality of life, as well as the fact that therapy is often expensive, making it unaffordable to many, have created anxiety among patients, families, and friends. One of the reasons for the failure of cancer therapeutics is that the approaches do not consider cancer holistically. Characteristically, all breast cancer cells and their microenvironmental capillary endothelial cells express asparagine-linked (N-linked) glycoproteins with diverse structures. We tested a small biological molecule, Tunicamycin, that blocks a specific step of the protein N-glycosylation pathway in the endoplasmic reticulum (ER), i.e., the catalytic activity of N-acetylglusosaminyl 1-phosphate transferase (GPT). The outcome was overwhelmingly exciting. Tunicamycin quantitatively inhibits angiogenesis in vitro and in vivo, and inhibits the breast tumor progression of multiple subtypes in pre-clinical mouse models with "zero" toxicity. Mechanistic details support ER stress-induced unfolded protein response (upr) signaling as the cause for the apoptotic death of both cancer and the microvascular endothelial cells. Additionally, it interferes with Wnt signaling. We therefore conclude that Tunicamycin can be expected to supersede the current therapeutics to become a glycotherapy for treating breast cancer of all subtypes.
    Keywords:  ER stress; N-acetylglucosaminyl 1-phosphate transferase; angiogenesis; asparagine-linked glycoprotein; breast cancer; glycotherapy; tunicamycin; unfolded protein response; upr
  8. Biomedicines. 2022 Apr 12. pii: 887. [Epub ahead of print]10(4):
      (1) Background: Meningiomas are the most common intracranial tumors in adults; currently there is no effective chemotherapy for malignant meningiomas. The effect of disulfiram (DSF)/Copper (Cu) on meningiomas remains unclear; (2) Methods: The impact of DSF/Cu on cell viability of meningioma adhesion cells (MgACs) and sphere cells (MgSCs) was assessed via MTS assay. The effects of DSF/Cu on intracellular Cu levels, cell senescence, and apoptosis were analyzed using CopperGreen, C12FDG, and Annexin V assays. Intracellular ALDH isoform expression and canonical pathway expression after DSF/Cu treatment were analyzed using mRNA microarray and Ingenuity Pathway Analysis, with further verification through qRT-PCR and immunoblotting; (3) Results: The viability of MgACs and MgSCs were inhibited by DSF/Cu. DSF/Cu increased intracellular Cu levels and cellular senescence. DSF/Cu also induced ER stress in MgACs and activated the PERK/eIF2 pathway for further adaptive response, apoptosis, and autophagy. Finally, DSF/Cu inhibited the expression of different ALDH isoforms in MgACs and MgSCs; (4) Conclusions: DSF/Cu exerts cytotoxic effects against both meningioma cells and stem-like cells and has treatment potential for meningioma.
    Keywords:  ALDH; DSF; ER stress; copper; disulfiram; meningioma; meningioma stem-like cells
  9. J Med Chem. 2022 Apr 19.
      Using a cytotoxicity-based phenotypic screen of a highly diverse library of 20,000 small-molecule compounds, we identified a quinolin-8-yl-nicotinamide, QN519, as a promising lead. QN519 represents a novel scaffold with drug-like properties, showing potent in vitro cytotoxicity in a panel of 12 cancer cell lines. Subsequently, lead optimization campaign generated compounds with IC50 values < 1 μM. An optimized compound, QN523, shows significant in vivo efficacy in a pancreatic cancer xenograft model. QN523 treatment significantly increased the expression of HSPA5, DDIT3, TRIB3, and ATF3 genes, suggesting activation of the stress response pathway. We also observed a significant increase in the expression of WIPI1, HERPUD1, GABARAPL1, and MAP1LC3B, implicating autophagy as a major mechanism of action. Due to the lack of effective treatments for pancreatic cancer, discovery of novel agents such as the QN series of compounds with unique mechanism of action has the potential to fulfill a clear unmet medical need.