The increased risk for acquiring secondary illnesses in people living with HIV (PLWH) has been associated with immune dysfunction. We have previously found that circulating monocytes from PLWH ...display a trained phenotype. Here, we evaluated the metabolic profile of these cells and found increased mitochondrial respiration and glycolysis of monocyte-derived macrophages (MDMs) from PLWH. We additionally found that cART shifted the energy metabolism of MDMs from controls toward increased utilization of mitochondrial respiration. Importantly, both downregulation of IKAROS expression and inhibition of the mTOR pathway reversed the metabolic profile of MDMs from PLWH and cART-treated control-MDMs. Altogether, this study reveals a very specific metabolic adaptation of MDMs from PLWH, which involves an IKAROS/mTOR-dependent increase of mitochondrial respiration and glycolysis. We propose that this metabolic adaptation decreases the ability of these cells to respond to environmental cues by “locking” PLWH monocytes in a pro-inflammatory and activated phenotype.
•Monocyte-derived macrophages from PLWH display enhanced mitochondrial respiration and glycolysis.•Dysfunctional IKAROS/mTOR axis drives the PLWH-macrophages metabolic phenotype.•HIV antiretrovirals alter both expression of IKAROS and metabolism of macrophages.
Abstract
Glioblastoma is a devastating malignancy with a median survival of approximately 15 months. This aggressive tumor originates from the glial cells and accounts for nearly 50% of adult brain ...tumors. Glioblastomas are characterized by rapid proliferation and resistance to standard treatment of surgery, temazolamide and radiation therapy. MicroRNAs are short single-stranded non-coding RNAs that regulate gene expression in both normal and pathological conditions. We have previously found downregulation of miR-3189-3p in glioblastomas and astrocytomas. Using in vitro models, we demonstrated that ectopic expression of this miRNA inhibited glioblastoma cell growth and migration through downregulation of the splicing factor SF3B2 and the guanine nucleotide exchange factor p63RhoGEF, respectively. The miR-3189-3p-mediated inhibition of glioblastoma growth in vivo further confirmed the anti-cancer activity of this microRNA.
Given the strong biological effect of this miRNA on glioblastoma cells, we sought to investigate the implication of other gene targets in miR-3189-3p-mediated effects. The elevated expression of MYC oncogene is found in a variety of cancer types, including glioblastoma. Here, we demonstrated that overexpression of miR-3189-3p results in downregulation of MYC. Since this gene is not a predicted target for miR-3189-3p, we hypothesized that this modulation of MYC expression is mediated through the translational repressor, TIA1 cytotoxic granule-associated RNA binding protein-like 1 (TIAL1, also called TIAR). We tested the levels of TIAR in cells treated with miR-3189-3p and found no changes in TIAR expression. However, the downregulation of MYC was dependent on TIAR expression, as determined through siRNA-mediated downregulation of TIAR. Further studies are needed to elucidate molecular mechanisms of TIAR-dependent downregulation of MYC by miR-3189-3p. In addition, a putative binding site for miR-3189-3p is located within the open reading frame of MYC; therefore, studies will be performed to determine whether miR-3189-3p downregulates MYC by directly binding outside the 3’-UTR of this transcript.
Citation Format: Duane Jeansonne, Krzysztof Reiss, Francesca Peruzzi. Downregulation of MYC by miR-3189-3p in glioblastoma. abstract. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1902.
The accumulation of myeloid‐derived suppressor cells (MDSC) in tumor‐bearing hosts is a hallmark of malignancy‐associated inflammation and a major mediator for the induction of T cell suppression in ...cancer. MDSC can be divided phenotypically into granulocytic (G‐MDSC) and monocytic (Mo‐MDSC) subgroups. Several mechanisms mediate the induction of T cell anergy by MDSC; however, the specific role of these pathways in the inhibitory activity of MDSC subpopulations remains unclear. Therefore, we aimed to determine the effector mechanisms by which subsets of tumor‐infiltrating MDSC block T cell function. We found that G‐MDSC had a higher ability to impair proliferation and expression of effector molecules in activated T cells, as compared to Mo‐MDSC. Interestingly, both MDSC subgroups inhibited T cells through nitric oxide (NO)‐related pathways, but expressed different effector inhibitory mechanisms. Specifically, G‐MDSC impaired T cells through the production of peroxynitrites (PNT), while Mo‐MDSC suppressed by the release of NO. The production of PNT in G‐MDSC depended on the expression of gp91phox and endothelial NO synthase (eNOS), while inducible NO synthase (iNOS) mediated the generation of NO in Mo‐MDSC. Deletion of eNOS and gp91phox or scavenging of PNT blocked the suppressive function of G‐MDSC and induced anti‐tumoral effects, without altering Mo‐MDSC inhibitory activity. Furthermore, NO‐scavenging or iNOS knockdown prevented Mo‐MDSC function, but did not affect PNT production or suppression by G‐MDSC. These results suggest that MDSC subpopulations utilize independent effector mechanisms to regulate T cell function. Inhibition of these pathways is expected to specifically block MDSC subsets and overcome immune suppression in cancer.
What's new?
Myeloid‐derived suppressor cells (MDSC) are major mediators of T‐cell suppression in cancer, though the pathways by which tumor‐infiltrating MDSC subpopulations impair T‐cell function are not well understood. This study shows that both granulocytic (G‐) MDSC and monocytic (Mo‐) MDSC act through nitric oxide (NO)‐related pathways but utilize different effector mechanisms. Whereas G‐MDSC inhibited T cells through peroxynitrite (PNT) production, Mo‐MDSC suppressed T cells through NO release. The differential effector mechanisms suggest that each subset of MDSC could be blocked specifically and independently to overcome immune suppression in cancer.
Purpose: This study examined the seminal vesicle fluid (SVF) as a potential local source of insulin-like growth factor-I (IGF-I) in
the peripheral zone of the prostate.
Experimental Design: IGF-I ...levels in seminal fluid were measured. The levels of the IGF-I receptor (IGF-IR) in its active, phosphorylated form
as well as direct downstream targets were examined in the peripheral zone of the prostate.
Results: In situ , we find that the IGF-IR is activated in the peripheral zone in areas of atrophy, prostatic intraepithelial hyperplasia,
and cancer. In addition, immunostaining reveals preferential activation of the IGF-IR in p63-positive cells in areas of intermediate
basal cell hyperplasia in the peripheral zone, indicating that prostate progenitor cells are highly sensitive to increases
in local IGF-I levels. These areas of basal cell hyperplasia occur at high incidence in the peripheral zone of the prostate.
Relatively high levels of IGF-I were identified in SVF. In addition, we find that SVF can stimulate the proliferation of both
normal and cancer-derived prostate cells.
Conclusions: These results suggest that SVF is a local source of IGF-I that provides chronic stimulation of prostate cells. This chronic
stimulation could contribute to the development of prostate cancer in older men.
LNCaP cells are human prostatic cancer cells that have a frame-shift mutation of the tumor suppressor gene PTEN and do not express the insulin receptor substrate-1 (IRS-1), a major substrate of the ...type 1 insulin-like growth factor receptor (IGF-IR). Ectopic expression of IRS-1 in LNCaP cells increases cell adhesion and decreases cell motility by an IGF-I-independent mechanism. We show now that these effects of IRS-1 are accompanied by serine phosphorylation of IRS-1 and are inhibited by inhibitors of phosphatidylinositol 3-kinase (PI3K). We have confirmed the requirement for PI3K activity and serine phosphorylation by the use of IRS-1 mutants, expressed in LNCaP cells. Serine phosphorylation inhibits IGF-I-induced tyrosyl phosphorylation of IRS-1, which is restored by the expression of wild-type PTEN or by inhibition of PI3K activity. Finally, IRS-1 in LNCaP cells co-immunoprecipitates with integrin alpha 5 beta 1, and the association is again IGF-I-independent. We conclude that in LNCaP cells, IRS-1 is serine phosphorylated by PI3K, generating effects that are different, and even opposite, from those generated by IGF-I.
Abstract
Background
Most cervical cancers are directly linked to oncogenic or high-risk human papillomavirus (HR-HPV) infection. This study evaluates associations between diet quality and genital HPV ...infection in women.
Methods
This study included 10 543 women from the 2003–2016 National Health and Nutrition Examination Survey. The outcome was the genital HPV infection status (HPV-negative, low-risk LR HPV, and HR-HPV). Dietary quality was evaluated using the Healthy Eating Index (HEI), in which a higher score indicates a better diet quality.
Results
Women who did not consume total fruits (15.8%), whole fruits (27.5%), or green vegetables and beans (43%) had a significantly higher risk of HR-HPV infection than women who complied with the Dietary Guidelines for Americans (HR-HPV odds ratio = 1.76, 1.63, and 1.48 for a HEI score of 0 vs 5, respectively) after adjusting confounding factors. Similar results of these food components on LR-HPV infection were found. In addition, intake of whole grains and dairy was inversely associated with LR-HPV infection.
Conclusions
This study showed that women who did not eat fruits, dark-green vegetables, and beans had a higher risk of genital HR-HPV infection. Intake of these food components is suggested for women to prevent HPV carcinogenesis.
This study evaluates associations between diet quality using the Healthy Eating Index and genital HPV infection in women. The results showed women who did not eat fruits, dark-green vegetables, and beans had an elevated risk of genital oncogenic HPV infection.
Abstract
Our laboratory has previously characterized a microRNA, miR-3189-3p, with potent anti-cancer activity against glioblastoma and triple negative breast cancer (TNBC), two of the most ...aggressive types of tumors. Intriguingly, while miR-3189-3p inhibits proliferation, migration, and invasion of glioblastoma and TNBC cells, it does not induce apoptosis. The BCL2 family of proteins controls mitochondrial-mediated cell death through binding affinity and abundance of pro- and anti-apoptotic factors. Here, we investigated the mechanisms of the cytostatic effect of miR-3189-3p on MDA-MB-231 cells and found that the BCL2-family members and pro-apoptotic factors BAK1, BMF, and HRK, which are predicted gene target of this miRNA, are indeed downregulated by the miRNA mimic. In addition, we found that expression of miR-3189-3p improved the metabolic fitness of TNBC cells through increasing both mitochondrial respiration and glycolysis. Ongoing experiments are aimed at understanding how changes in the metabolic profile and cytostatic activity of miR-3189-3p could be used for therapeutic intervention against this aggressive tumor.
Citation Format: Cecilia Vittori, Hassan Yousefi, Krzysztof Reiss, Francesca Peruzzi. The cytostatic effect of miR-3189-3p in triple negative breast cancer cells involves inhibition of mitochondrial-mediated apoptosis 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 1545.
Purα is a sequence-specific nucleic acid binding protein that is involved in multiple cellular functions including regulation of transcription, initiation of DNA replication, cell cycle progression, ...and neuronal cell differentiation. Its potential role in DNA repair has not been explored. We have now analyzed the role of Purα in the cellular response to replication-associated DNA repair of double-strand breaks (DSBs) using Purα knockout mouse embryo fibroblasts (MEFs). We found that Purα negative cells are hypersensitive to the DNA replication inhibitor, hydroxyurea (HU), and that HU induces excessive DSBs, which delayed the resumption of cell cycle progression after HU treatment. Reintroduction of Purα into Purα null cells reduced the accumulation of DSBs and enhanced DNA end joining. These results suggest a role for Purα as a caretaker protein that is involved in the repair of DSBs induced by stalled replication forks.
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