Guanylate-binding protein 1 (GBP1) is a large GTPase of the dynamin superfamily involved in the regulation of membrane, cytoskeleton, and cell cycle progression dynamics. In many cell types, such as ...endothelial cells and monocytes, GBP1 expression is strongly provoked by interferon γ (IFNγ) and acts to restrain cellular proliferation in inflammatory contexts. In immunity, GBP1 activity is crucial for the maturation of autophagosomes infected by intracellular pathogens and the cellular response to pathogen-associated molecular patterns. In chronic inflammation, GBP1 activity inhibits endothelial cell proliferation even as it protects from IFNγ-induced apoptosis. A similar inhibition of proliferation has also been found in some tumor models, such as colorectal or prostate carcinoma mouse models. However, this activity appears to be context-dependent, as in other cancers, such as oral squamous cell carcinoma and ovarian cancer, GBP1 activity appears to anchor a complex, taxane chemotherapy resistance profile where its expression levels correlate with worsened prognosis in patients. This discrepancy in GBP1 function may be resolved by GBP1's involvement in the induction of a cellular senescence phenotype, wherein anti-proliferative signals coincide with potent resistance to apoptosis and set the stage for dysregulated proliferative mechanisms present in growing cancers to hijack GBP1 as a pro- chemotherapy treatment resistance (TXR) and pro-survival factor even in the face of continued cytotoxic treatment. While the structure of GBP1 has been extensively characterized, its roles in inflammation, TXR, senescence, and other biological functions remain under-investigated, although initial findings suggest that GBP1 is a compelling target for therapeutic intervention in a variety of conditions ranging from chronic inflammatory disorders to cancer.
Sodium butyrate (NaBt) is the byproduct of anaerobic microbial fermentation inside the gastro-intestinal tract that could reach up to 20mM, and has been shown to inhibit the growth of various ...cancers. Herein, we evaluated its effect on mitochondrial fusion and associated induction of apoptosis in colorectal cancer cells (CRC). NaBt treatment at physiological (1-5mM) concentrations for 12 and 24h decreased the cell viability and induced G2-M phase cell cycle arrest in HCT116 (12h) and SW480 human CRC cells. This cell cycle arrest was associated with mitochondria-mediated apoptosis accompanied by a decrease in survivin and Bcl-2 expression, and generation of reactive oxygen species (ROS). Furthermore, NaBt treatment resulted in a significant decrease in the mitochondrial mass which is an indicator of mitochondrial fusion. Level of dynamin-related protein 1 (DRP1), a key regulator of mitochondrial fission and fusion where its up-regulation correlates with fission, was found to be decreased in CRC cells. Further, at early treatment time, DRP1 down-regulation was noticed in mitochondria which later became drastically reduced in both mitochondria as well as cytosol. DRP1 is activated by cyclin B1-CDK1 complex by its ser616 phosphorylation in which both cyclin B1-CDK1 complex and phospho-DRP1 (ser616) were strongly reduced by NaBt treatment. DRP1 was observed to be regulated by apoptosis as pan-caspase inhibitor showing rescue from NaBt-induced apoptosis also caused the reversal of DRP1 to the normal level as in control proliferating cells. Together, these findings suggest that NaBt can modulate mitochondrial fission and fusion by regulating the level of DRP1 and induce cell cycle arrest and apoptosis in human CRC cells.
To circumvent Warburg effect, several clinical trials for different cancers are utilising a combinatorial approach using metabolic reprogramming and chemotherapeutic agents including metformin. The ...majority of these metabolic interventions work via indirectly activating AMP-activated protein kinase (AMPK) to alter cellular metabolism in favour of oxidative phosphorylation over aerobic glycolysis. The effect of these drugs is dependent on glycaemic and insulin conditions. Therefore, development of small molecules, which can activate AMPK, irrespective of the energy state, may be a better approach for triple-negative breast cancer (TNBC) treatment.
Therapeutic effect of SU212 on TNBC cells was examined using in vitro and in vivo models.
We developed and characterised the efficacy of novel AMPK activator (SU212) that selectively induces oxidative phosphorylation and decreases glycolysis in TNBC cells, while not affecting these pathways in normal cells. SU212 accomplished this metabolic reprogramming by activating AMPK independent of energy stress and irrespective of the glycaemic/insulin state. This leads to mitotic phase arrest and apoptosis in TNBC cells. In vivo, SU212 inhibits tumour growth, cancer progression and metastasis.
SU212 directly activates AMPK in TNBC cells, but does not hamper glucose metabolism in normal cells. Our study provides compelling preclinical data for further development of SU212 for the treatment of TNBC.
The newly emerged severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) cause life‐threatening diseases in millions of people worldwide, in particular, in patients with cancer, and there is an ...urgent need for antiviral agents against this infection. While in vitro activities of artemisinins against SARS‐CoV‐2 and cancer have recently been demonstrated, no study of artemisinin and/or synthetic peroxide‐based hybrid compounds active against both cancer and SARS‐CoV‐2 has been reported yet. However, the hybrid drug's properties (e. g., activity and/or selectivity) can be improved compared to its parent compounds and effective new agents can be obtained by modification/hybridization of existing drugs or bioactive natural products. In this study, a series of new artesunic acid and synthetic peroxide based new hybrids were synthesized and analyzed in vitro for the first time for their inhibitory activity against SARS‐CoV‐2 and leukemia cell lines. Several artesunic acid‐derived hybrids exerted a similar or stronger potency against K562 leukemia cells (81–83 % inhibition values) than the reference drug doxorubicin (78 % inhibition value) and they were also more efficient than their parent compounds artesunic acid (49.2 % inhibition value) and quinoline derivative (5.5 % inhibition value). Interestingly, the same artesunic acid‐quinoline hybrids also show inhibitory activity against SARS‐CoV‐2 in vitro (EC50 13–19 μm) and no cytotoxic effects on Vero E6 cells (CC50 up to 110 μM). These results provide a valuable basis for design of further artemisinin‐derived hybrids to treat both cancer and SARS‐CoV‐2 infections.
Hybrid power: New artemisinin‐ and synthetic peroxide‐based hybrids, highly active in vitro against leukemia cell lines and SARS‐CoV‐2, were synthesized. Remarkably, the most active anti‐cancer hybrid compounds are also the most potent and selective against SARS‐CoV‐2.
The kinetics of NKG2C
adaptive natural killer (ANK) cells and NKG2A
inhibitory NK (iNK) cells with respect to the incidence of SARS-CoV-2 infection were studied for 6 months in a cohort of healthcare ...workers following the administration of the heat-killed
(Mw group) in comparison to a control group. In both groups, corona virus disease 2019 (COVID-19) correlated with lower NKG2C
ANK cells at baseline. There was a significant upregulation of NKG2C expression and IFN-γ release in the Mw group (p=0.0009), particularly in those with a lower baseline NKG2C expression, along with the downregulation of iNK cells (p<0.0001). This translated to a significant reduction in the incidence and severity of COVID-19 in the Mw group (incidence risk ratio-0.15, p=0.0004). RNA-seq analysis at 6 months showed an upregulation of the ANK pathway genes and an enhanced ANK-mediated antibody-dependent cellular cytotoxicity (ADCC) signature. Thus, Mw was observed to have a salutary impact on the ANK cell profile and a long-term upregulation of ANK-ADCC pathways, which could have provided protection against COVID-19 in a non-immune high-risk population.
Mycobacterium-
(Mw) was shown to boost adaptive natural killer (ANK) cells and protect against COVID-19 during the first wave of the pandemic. As a follow-up of the trial, 50 healthcare workers (HCW) ...who had received Mw in September 2020 and subsequently received at least one dose of ChAdOx1 nCoV-19 vaccine (Mw + ChAdOx1 group) were monitored for symptomatic COVID-19 during a major outbreak with the delta variant of SARS-CoV-2 (April-June 2021), along with 201 HCW receiving both doses of the vaccine without Mw (ChAdOx1 group). Despite 48% having received just a single dose of the vaccine in the Mw + ChAdOx1 group, only two had mild COVID-19, compared to 36 infections in the ChAdOx1 group (HR-0.46,
= 0.009). Transcriptomic studies revealed an enhanced adaptive NK cell-dependent ADCC in the Mw + ChAdOx1 group, along with downregulation of the TLR2-MYD88 pathway and concomitant attenuation of downstream inflammatory pathways. This might have resulted in robust protection during the pandemic with the delta variant.
Abstract
Medulloblastoma is the most common pediatric brain tumor in children. Patients diagnosed with MYC-amplified group 3 (G3) have a dismal prognosis with a 5 year survival rate of < 50%. ...Standard of care consists of maximal resection surgery followed by craniospinal irradiation and chemotherapy, but patients experience diminished quality of life from these extensive treatment regimens. Recent observations have shown that Y-box binding protein 1 (YBX1) is upregulated across human medulloblastoma subgroups compared to normal cerebellum. G3 patient tumors have the highest expression of YBX1, possibly due to an oncogenic feedback loop. We utilized an orthogonal pharmacogenetic approach to target YBX1. Knockdown/out of YBX1 significantly inhibits proliferation of G3 MB cells in vitro and in vivo. We next investigated the therapeutic potential of a novel YBX1 inhibitor, which displays single agent efficacy at decreasing the proliferation of medulloblastoma cell line derived xenografts (CDX). Since YBX1 targeting downregulated ABC transporter expression, we hypothesize that inhibition of YBX1 may sensitize medulloblastoma cells to chemotherapeutic agents. We performed drug synergy experiments combining YBX1 inhibition and commonly used standard of care chemotherapy. We identify that combining YBX1 inhibition sensitizes to both gemcitabine and vincristine in vitro and in vivo. We are currently evaluating this YBX1 inhibitor in an “anchor-probe” screen combining with all currently FDA approved drugs. Our findings impart an alluring prospect of targeting YBX1 in combination with chemotherapy, and possibly other compounds could improve patients’ outcomes.
Abstract Medulloblastoma is the most common malignant pediatric brain tumor, with some patients having abysmal survival despite an intense therapeutic regimen. A significant barrier to effective ...outcomes is cell-intrinsic resistance to chemo- and radio- therapy. Using a batch-normalized bulk RNA-seq dataset (GSE124814) comprised of 1350 MB samples and 291 normal cerebella, we reveal upregulation of Y-box binding protein 1 (YBX1) in MB compared to normal cerebellum. Further analysis of this dataset and others demonstrates a significant correlation between MYC and YBX1 expression in G3 tumors. Proteomics analysis also reveals higher YBX1 in G3 tumors characterized by hyperstability of MYC. Using a well-established ex vivo model, we demonstrate increased YBX1 expression as normal cerebellar progenitor cells transition to tumorigenic G3 MB stem-like cells. Deletion of YBX1 in these progenitor cells limits tumorigenesis suggesting a requirement for YBX1 in tumor initiation. We utilized an orthogonal pharmacogenetic approach to inhibit YBX1 and determine its effects on G3 MB tumor biology. Genetic depletion of YBX1 significantly reduced cellular proliferation and antagonized MYC expression in vitro. Orthotopic implantation of these YBX1KO G3 MB cells leads to increased tumor latency and animal survival. Transcriptomic analysis reveals a de-repression of neuronal target genes as well as suppression of MYC-activated genes. Evaluation of SU056, a YBX1 targeting small molecule, revealed both single agent efficacy as well as synergism with chemo- and radio- therapy. Further analysis revealed efficacy in SHH MB, even in tumors with mutant p53, suggesting cross-subgroup use for SU056. In silico docking identified binding of SU056 in the mRNA recognition domain of YBX1. Disruption of YBX1-RNA binding impacts the stability of known oncogenic transcripts, important for tumorigenesis and progression. Our findings corroborate previous identification of YBX1 as a chemoresistance factor and validate pre-clinical targeting of YBX1 to improve patient outcomes.
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