Abstract Background Under conditions of hypoxia, cancer cells with hypoxia inducible factor-1α (HIF-1α) from heterogeneous tumor cells show greater aggression and progression in an effort to compensate for harsh environmental conditions. Extensive study on the stability of HIF-1α under conditions of acute hypoxia in cancer progression has been conducted, however, understanding of its involvement during the chronic phase is limited. Methods In this study, we investigated the effect of SIRT1 on HIF1 stability in a typical chronic hypoxic conditon that maintains cells for 24 h under hypoxia using Western blotting, co-IP, measurement of intracellular NAD + and NADH levels, semi-quantitative RT-PCR analysis, invasion assay, gene knockdown. Results Here we demonstrated that the high concentration of pyruvate in the medium, which can be easily overlooked, has an effect on the stability of HIF-1α. We also demonstrated that NADH functions as a signal for conveyance of HIF-1α degradation via the SIRT1 and VHL signaling pathway under conditions of chronic hypoxia, which in turn leads to attenuation of hypoxically strengthened invasion and angiogenic activities. A steep increase in the level of NADH occurs during chronic hypoxia, leading to upregulation of acetylation and degradation of HIF-1α via inactivation of SIRT1. Of particular interest, p300-mediated acetylation at lysine 709 of HIF-1α is recogonized by VHL, which leads to degradation of HIF-1α via ubiquitin/proteasome machinary under conditions of chronic hypoxia. In addition, we demonstrated that NADH-elevation-induced acetylation and subsequent degradation of HIF-1α was independent of proline hydroxylation. Conclusions Our findings suggest a critical role of SIRT1 as a metabolic sensor in coordination of hypoxic status via regulation of HIF-1α stability. These results also demonstrate the involvement of VHL in degradation of HIF-1α through recognition of PHD-mediated hydroxylation in normoxia and p300-mediated HIF-1α acetylation in hypoxia.
To retarget oncolytic herpes simplex virus (oHSV) to cancer-specific antigens, we designed a novel, double-retargeted oHSV platform that uses single-chain antibodies (scFvs) incorporated into both glycoprotein H and a bispecific adapter expressed from the viral genome to mediate infection predominantly via tumor-associated antigens. Successful retargeting was achieved using a nectin-1-detargeted HSV that remains capable of interacting with herpesvirus entry mediator (HVEM), the second canonical HSV entry receptor, and is, therefore, recognized by the adapter consisting of the virus-binding N-terminal 82 residues of HVEM fused to the target-specific scFv. We tested both an epithelial cell adhesion molecule (EpCAM)- and a human epidermal growth factor receptor 2-specific scFv separately and together to target cells expressing one, the other, or both receptors. Our results show not only dose-dependent, target receptor-specific infection
Radioimmunotherapy (RIT) serves as a targeted therapy for non-Hodgkin lymphomas (NHL). Although HIF(Hypoxia-inducible factors)-1α is an important biomarker during radiation therapy, its role in NHL is unclear. Atorvastatin (ATV) is used as a combination drug for chemotherapy.
Abstract Oncolytic virotherapy is a new modality of immunotherapy using spontaneously occurring or genetically engineered viruses to selectively replicate in and kill cancer cells, no harming normal cells. Currently, various oncolytic herpes simplex virus (oHSVs) with enhanced tumor targeting, antitumor efficacy, and safety have been explored in many different models, and on a range of tumor targets. It has been a difficult task to completely retarget HSV to cancer-specific antigens at the plasma membrane of selected tumors, while maintaining the fully lytic potential of HSV. This approach achieved by a deep knowledge of virus natural receptor recognition, binding, and entry mechanisms. Two strategies have been employed including the incorporation of single-chain antibodies (scFv) into gD, gC or gH and the use of soluble adapter molecules that are capable of binding to both HSV and the specific receptor on the target cell. In the previous study, we first reported that HSV could retarget to gastric carcinoma cells by HVEM-CEA adapter molecule. Although we have been shown reasonable efficiency of retargeted cell transduction in vitro and in vivo, it required purification of the adapter protein and continuous addition to the virus prior to infection. To overcome the limitations of adapter molecules, we developed a self-retargeting system by incorporation of adapter expression cassette into the HSV genome that enables the sustained secretion of adapter protein while the viral replication in infected tumor cells. Furthermore, to strengthen the retargeting modality, we constructed a novel, double targeted oHSV, carries no deletion/attenuation, consisting of self-retargeting adapter and modified gH to EpCAM. Our results show that the initial infection and subsequent viral spread depend on cellular EpCAM expression. When injected intravenously (i.v.), they caused no harm to tumor-free mice up to the maximum tested dosage (2 x 108 PFU). When a single intratumoral dose of double targeting oHSV (2 x 106 infectious units) were administered in a xenograft model they rendered 80% of mice tumor-free. Our findings suggest that the double retargeting platform of HSV carrying self-retargeting adapter and modified gH may be potent in cancer-specific cell killing and thus useful for the treatment of EpCAM expressing various cancers. Citation Format: Hyunjung Baek, Hyun-Yoo Joo, Eun-Ran Park, Chun-Seob Ahn, Sujung Lee, Hyeri Kim, Mihee Han, Bora Kim, Heechung Kwon. Double targeting oncolytic herpes simplex virus type 1 (oHSV-1) exhibits effective antitumor activity against EpCAM-expressing cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3292.
Cluh is a cytosolic protein that is known to specifically bind the mRNAs of nuclear-encoded mitochondrial proteins and play critical roles in mitochondrial biogenesis. Here, we report the role of Cluh in adipogenesis. Our study shows that mRNA expression of Cluh is stimulated during adipogenesis, and that cAMP/Creb signalling increases its transcription. Cluh depletion impaired proper adipocyte differentiation, with reductions seen in lipid droplets and adipogenic marker gene expression. Interestingly, the inductions of the brown adipocyte-specific genes, Ucp1, Cidea and Cox7a1, are severely blocked by Cluh depletion during brown adipogenesis. Mitochondrial respiration and the stability of mRNAs encoding mitochondrial proteins are reduced by Cluh depletion during brown adipogenesis. These results suggest that Cluh, which is induced during adipogenesis, promotes the post-transcriptional regulation of mitochondrial proteins and supports differentiation.
// Su-Hyeon Kim 1 , Eun-Ran Park 1 , Eugene Cho 1 , Won-Hee Jung 1 , Ju-Yeon Jeon 1 , Hyun-Yoo Joo 1 , Kee-Ho Lee 1 , Hyun-Jin Shin 1 1 Division of Radiation Cancer Research, Korea Institute of Radiological & Medical Sciences, Seoul 139-706, Republic of Korea Correspondence to: Kee-Ho Lee, email: khlee@kirams.re.kr Hyun-Jin Shin, email: hjshin@kirams.re.kr Keywords: Mael, oncogenic transformation, genetic integrity, oncogene, ATM Received: May 02, 2016 Accepted: November 21, 2016 Published: December 01, 2016 ABSTRACT Germ line-specific genes are activated in somatic cells during tumorigenesis, and are accordingly referred to as cancer germline genes. Such genes that act on piRNA (Piwi-interacting RNA) processing play an important role in the progression of cancer cells. Here, we show that the spermatogenic transposon silencer maelstrom (Mael), a piRNA-processing factor, is required for malignant transformation and survival of cancer cells. A specific Mael isoform was distinctively overexpressed in diverse human cancer cell lines and its depletion resulted in cancer-specific cell death, characterized by apoptosis and senescence, accompanied by an increase in reactive oxygen-species and DNA damage. These biochemical changes and death phenotypes induced by Mael depletion were dependent on ATM. Interestingly Mael was essential for Myc/Ras-induced transformation, and its overexpression inhibited Ras-induced senescence. In addition, Mael repressed retrotransposon activity in cancer cells. These results suggest that Mael depletion induces ATM-dependent DNA damage, consequently leading to cell death specifically in cancer cells. Moreover, Mael possesses oncogenic potential that can protect against genetic instability.
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