440 publications from this institution
Objective: Heme oxygenase-1 (HO-1) is a cytoprotective, proangiogenic and anti-inflammatory enzyme that is often upregulated in tumors. Overexpression of HO-1 in melanoma cells leads to enhanced tumor growth, augmented angiogenesis and resistance to anticancer treatment. The effect of HO-1 in host cells on tumor development is, however, hardly known. Methods and results: To clarify the effect of HO-1 expression in host cells on melanoma progression, C57BL/6xFvB mice of different HO-1 genotypes, HO-1+/+, HO-1+/−, and HO-1−/−, were injected with the syngeneic wild-type murine melanoma B16(F10) cell line. Lack of HO-1 in host cells did not significantly influence the host survival. Nevertheless, in comparison to the wild-type counterparts, the HO-1+/− and HO-1−/− males formed bigger tumors, and more numerous lung nodules; in addition, more of them had liver and spleen micrometastases. Females of all genotypes developed at least 10 times smaller tumors than males. Of importance, the growth of primary and secondary tumors was completely blocked in HO-1+/+ females. This was related to the increased infiltration of leukocytes (mainly lymphocytes T) in primary tumors. Conclusions: Although HO-1 overexpression in melanoma cells can enhance tumor progression in mice, its presence in host cells, including immune cells, can reduce growth and metastasis of melanoma.
Heme oxygenase-1 (HO-1) degrades heme to carbon monoxide (CO), biliverdin, and ferrous iron. As HO-1 expression is highly increased by stressful conditions, the major role of the enzyme is the protection against oxidative injury. Additionally, it regulates cell proliferation, modulates inflammatory response and facilitates angiogenesis. Beneficial activities of HO-1 have been recognized in many pathological states e.g. atherosclerosis, diabetes, ischemia/reperfusion injury or organ transplantation. Interestingly HO-1 expression is very often boosted in tumor tissues and could be further elevated in response to radio-, chemo-, or photodynamic therapy. A growing body of evidence suggests that HO-1 may play a role in tumor induction and can potently improve the growth and spread of tumors. This review discusses the implications of HO-1 properties for tumor proliferation and cell death, differentiation, angiogenesis and metastasis, and tumor-related inflammation. Finally, it suggests that pharmacological agents that regulate HO activity or HO-1 gene silencing may become powerful tools for preventing the onset or progression of various cancers and sensitize them to anticancer therapies.
Abstract Background Adeno-associated viral vectors (AAVs) are safe and efficient tools for delivery of therapeutic genes in numerous applications. Although they elicit only limited immune response in host cells, a recent study has demonstrated an association between decreasing transgene expression in the liver and induction of the immune response to cytoplasmic dsRNA. While AAVs are DNA vectors, it appears that their unique genome structure allows the generation of dsRNA in transduced cells. Since the expression cassette is flanked by inverted terminal repeats (ITRs), which can function as bidirectional promoters, assembly of sense and antisense transcripts can potentially result in formation of dsRNA structures, especially in cells exhibiting high transgene expression. Purpose In this study, we explored the mechanism of dsRNA recognition in cardiomyocytes, to unravel its role in the regulation of transgene expression from AAV vectors. Methods For this purpose, we utilised human iPSC-derived cardiomyocytes transduced with self-complementary AAV6 or AAV9 vectors encoding GFP. Since we focused on the long-term effects of transgene expression, all the analyses were performed 7–9 days after AAV transduction. Results We confirmed that ITR serves as a functional promoter in the cells, capable of maintaining approximately half of the fluorescence signal compared to the CMV promoter. Long-term transgene expression was associated with elevated expression of dsRNA sensors (MDA5, RIG-I, LGP2 and TLR3) and the appearance of small foci of dsRNA in the perinuclear region. Unlike an artificial ligand for dsRNA sensors, poly (I:C), dsRNA in AAV-transduced cells did not interact with the LGP2 protein. To induce dsRNA recognition, we stimulated the cells with IFNβ for 1 week, starting from day 1 after transduction. We found that transgene expression is significantly hampered in such conditions. Furthermore, IFNβ induced the direct interaction of dsRNA with the OAS1 protein in transduced cells. During viral infections, OAS1 and its effector nuclease RNAse L promote the degradation of mRNA to restrict the production of viral proteins. Since RNAse L is not specific for particular transcripts, we hypothesize that activation of the OAS1 pathway in transduced cells is responsible for downregulation of transgene expression. While IFNβ induced OAS1-dsRNA recognition, we did not observe such an event in cells transduced with AAV and maintained under standard conditions. In turn, AAV transduction resulted in a reduction in OAS1 expression at the mRNA and protein level, suggesting a possible reason for tolerance to dsRNA in transduced cardiomyocytes. Conclusions Our data present a novel mechanism of regulation of transgene expression in AAV-transduced cells involving OAS1–RNAse L pathway and provide deeper insight into the general signal transduction routes activated in response to cytosolic dsRNA in human iPSC-derived cardiomyocytes. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Science Centre - PRELUDUM grant 2019/33/N/NZ1/03066Jagiellonian University, Faculty of Biochemistry, Biophysics and Biotechnology - grant for young scientists MNS 6/2020
It seems that interplay between HO-1 and miRNAs may be important in regulating fates of stem and progenitor cells and needs further intensive studies.
Objective— Pleiotropic atheroprotective effects of HMG-CoA reductase inhibitors may be mediated on the level of vascular gene transcription. The aim of this study was to characterize the effects of statins on the activation of transcription factors known to regulate inflammation and cell proliferation/differentiation. Methods and Results— Simvastatin, atorvastatin, and lovastatin (0.1 to 10 μmol/L) inhibited the binding of nuclear proteins to both the nuclear factor-kappa B (NF-κB) and activator protein-1 (AP-1) DNA consensus oligonucleotides in human endothelial and vascular smooth muscle cells as assessed by electrophoretic mobility shift assay (EMSA). The inhibitory effects of statins on NF-κB or AP-1–dependent transcriptional activity were examined by transient transfection studies. HMG-CoA reductase inhibitors upregulated IκB-α protein levels in endothelial cells and decreased c-Jun mRNA expression in smooth muscle cells as analyzed by Western and Northern blotting, respectively. Furthermore, statins inhibited DNA binding of hypoxia-inducible factor-1α. Downstream effects of statins included inhibition of plasminogen activator inhibitor-1 and vascular endothelial growth factor-A mRNA levels in endothelial cells. Conclusions— HMG-CoA reductase inhibitors downregulate the activation of transcription factors NF-κB, AP-1, and hypoxia-inducible factor-1α. These findings support the concept that statins have antiinflammatory and antiproliferative effects that are relevant in the treatment of atherosclerotic diseases.
