HMGA1 Modulates Gene Transcription Sustaining a Tumor Signalling Pathway Acting on the Epigenetic Status of Triple-Negative Breast Cancer Cells

HMGA1 regulates trabectedin sensitivity in advanced soft-tissue sarcoma (STS): A Spanish Group for Research on Sarcomas (GEIS) study

HMGA1 is a structural epigenetic chromatin factor that has been associated with tumor progression and drug resistance. Here, we reported the prognostic/predictive value of HMGA1 for trabectedin in advanced soft-tissue sarcoma (STS) and the effect of inhibiting HMGA1 or the mTOR downstream pathway in trabectedin activity. The prognostic/predictive value of HMGA1 expression was assessed in a cohort of 301 STS patients at mRNA (n = 133) and protein level (n = 272), by HTG EdgeSeq transcriptomics and immunohistochemistry, respectively. The effect of HMGA1 silencing on trabectedin activity and gene expression profiling was measured in leiomyosarcoma cells. The effect of combining mTOR inhibitors with trabectedin was assessed on cell viability in vitro studies, whereas in vivo studies tested the activity of this combination. HMGA1 mRNA and protein expression were significantly associated with worse progression-free survival of trabectedin and worse overall survival in STS. HMGA1 silencing sensitized leiomyosarcoma cells for trabectedin treatment, reducing the spheroid area and increasing cell death. The downregulation of HGMA1 significantly decreased the enrichment of some specific gene sets, including the PI3K/AKT/mTOR pathway. The inhibition of mTOR, sensitized leiomyosarcoma cultures for trabectedin treatment, increasing cell death. In in vivo studies, the combination of rapamycin with trabectedin downregulated HMGA1 expression and stabilized tumor growth of 3-methylcholantrene-induced sarcoma-like models. HMGA1 is an adverse prognostic factor for trabectedin treatment in advanced STS. HMGA1 silencing increases trabectedin efficacy, in part by modulating the mTOR signaling pathway. Trabectedin plus mTOR inhibitors are active in preclinical models of sarcoma, downregulating HMGA1 expression levels and stabilizing tumor growth.

The role of high mobility group AT-hook 1 in viral infections: Implications for cancer pathogenesis

The crucial role of high mobility group AT-hook 1 (HMGA1) proteins in nuclear processes such as gene transcription, DNA replication, and chromatin remodeling is undeniable. Elevated levels of HMGA1 have been associated with unfavorable clinical outcomes and adverse differentiation status across various cancer types. HMGA1 regulates a diverse array of biological pathways, including tumor necrosis factor-alpha/nuclear factor-kappa B (TNF-α/NF-κB), epidermal growth factor receptor (EGFR), Hippo, Rat sarcoma/extracellular signal-regulated kinase (Ras/ERK), protein kinase B (Akt), wingless-related integration site/beta-catenin (Wnt/beta-catenin), and phosphoinositide 3-kinase/protein kinase B (PI3-K/Akt). While researchers have extensively investigated tumors in the reproductive, digestive, urinary, and hematopoietic systems, mounting evidence suggests that HMGA1 plays a critical role as a tumorigenic factor in tumors across all functional systems. Given its broad interaction network, HMGA1 is an attractive target for viral manipulation. Some viruses, including herpes simplex virus type 1, human herpesvirus 8, human papillomavirus, JC virus, hepatitis B virus, human immunodeficiency virus type 1, severe acute respiratory syndrome Coronavirus 2, and influenza viruses, utilize HMGA1 influence for infection. This interaction, particularly in oncogenesis, is crucial. Apart from the direct oncogenic effect of some of the mentioned viruses, the hit-and-run theory postulates that viruses can instigate cancer even before being completely eradicated from the host cell, implying a potentially greater impact of viruses on cancer development than previously assumed. This review explores the interplay between HMGA1, viruses, and host cellular machinery, aiming to contribute to a deeper understanding of viral-induced oncogenesis, paving the way for innovative strategies in cancer research and treatment.

LINC02532 by Mediating miR-541-3p/HMGA1 Axis Exerts a Tumor Promoter in Breast cancer

The newly discovered LINC02532 is abnormally expressed in a variety of cancers and promotes cancer progression. The research proposed to discover the biological and molecular mechanisms of LINC02532 in breast cancer (BCa). In the resected BCa tissue samples and adjacent normal tissues, LINC02532, miR-541-3p, and High Mobility Group A1 (HMGA1) levels were determined. Cell function experiments were carried out on the premise of cell transfection with relevant plasmids. Based on that, the influence of LINC02532, miR-541-3p, and HMGA1 on MCF-7 cell activities (proliferation, migration, invasion, cell cycle, and apoptosis) was determined, as well as on EMT. Additionally, animal experiments were allowed to support cell experimental conclusions on LINC02532. Finally, the mechanistic network of LINC02532, miR-541-3p, and HMGA1 was identified. It was BCa tissues highly expressing LINC02532 and HMGA1, while lowly expressing miR-541-3p. Functionally, LINC02532 depletion repressed the activities and EMT process of MCF-7 cells. Silencing LINC02532 delayed tumor growth in mice. In terms of mechanism, LINC02532 mainly existed in the cytoplasm and could mediate HMGA1 expression by absorbing miR-541-3p. The findings offer new insights into the molecular mechanisms of LINC02532 in BCa and, more importantly, new strategies for the clinical treatment of BCa.

Targeting HMGA1 contributes to immunotherapy in aggressive breast cancer while suppressing EMT

Metastasis is an obstacle to the clinical treatment of aggressive breast cancer (BC). Studies have shown that high mobility group A1 (HMGA1) is abnormally expressed in various cancers and mediates tumor proliferation and metastasis. Here, we provided more evidence that HMGA1 mediated epithelial to mesenchymal transition (EMT) through the Wnt/β-catenin pathway in aggressive BC. More importantly, HMGA1 knockdown enhanced antitumor immunity and improved the response to immune checkpoint blockade (ICB) therapy by upregulating programmed cell death ligand 1 (PD-L1) expression. Simultaneously, we revealed a novel mechanism by which HMGA1 and PD-L1 were regulated by the PD-L1/HMGA1/Wnt/β-catenin negative feedback loop in aggressive BC. Taken together, we believe that HMGA1 can serve as a target for the dual role of anti-metastasis and enhancing immunotherapeutic responses.

HMGA1 Regulates the Expression of Replication-Dependent Histone Genes and Cell-Cycle in Breast Cancer Cells

Breast cancer (BC) is the primary cause of cancer mortality in women and the triple-negative breast cancer (TNBC) is the most aggressive subtype characterized by poor differentiation and high proliferative properties. High mobility group A1 (HMGA1) is an oncogenic factor involved in the onset and progression of the neoplastic transformation in BC. Here, we unraveled that the replication-dependent-histone (RD-HIST) gene expression is enriched in BC tissues and correlates with HMGA1 expression. We explored the role of HMGA1 in modulating the RD-HIST genes expression in TNBC cells and show that MDA-MB-231 cells, depleted of HMGA1, express low levels of core histones. We show that HMGA1 participates in the activation of the HIST1H4H promoter and that it interacts with the nuclear protein of the ataxia-telangiectasia mutated locus (NPAT), the coordinator of the transcription of the RD-HIST genes. Moreover, we demonstrate that HMGA1 silencing increases the percentage of cells in G0/G1 phase both in TNBC and epirubicin resistant TNBC cells. Moreover, HMGA1 silencing causes an increase in epirubicin IC₅₀ both in parental and epirubicin resistant cells thus suggesting that targeting HMGA1 could affect the efficacy of epirubicin treatment.

Anti-hsa-miR-59 alleviates premature senescence associated with Hutchinson-Gilford progeria syndrome in mice

Hutchinson-Gilford progeria syndrome (HGPS) is a lethal premature aging disorder without an effective therapeutic regimen. Because of their targetability and influence on gene expression, microRNAs (miRNAs) are attractive therapeutic tools to treat diseases. Here we identified that hsa-miR-59 (miR-59) was markedly upregulated in HGPS patient cells and in multiple tissues of an HGPS mouse model (Lmna^G609G/G609G ), which disturbed the interaction between RNAPII and TFIIH, resulting in abnormal expression of cell cycle genes by targeting high-mobility group A family HMGA1 and HMGA2. Functional inhibition of miR-59 alleviated the cellular senescence phenotype of HGPS cells. Treatment with AAV9-mediated anti-miR-59 reduced fibrosis in the quadriceps muscle, heart, and aorta, suppressed epidermal thinning and dermal fat loss, and yielded a 25.5% increase in longevity of Lmna^G609G/G609G mice. These results identify a new strategy for the treatment of HGPS and provide insight into the etiology of HGPS disease.

HMGA1 positively regulates the microtubule-destabilizing protein stathmin promoting motility in TNBC cells and decreasing tumour sensitivity to paclitaxel

High Mobility Group A1 (HMGA1) is an architectural chromatin factor involved in the regulation of gene expression and a master regulator in Triple Negative Breast Cancer (TNBC). In TNBC, HMGA1 is overexpressed and coordinates a gene network that controls cellular processes involved in tumour development, progression, and metastasis formation. Here, we find that the expression of HMGA1 and of the microtubule-destabilizing protein stathmin correlates in breast cancer (BC) patients. We demonstrate that HMGA1 depletion leads to a downregulation of stathmin expression and activity on microtubules resulting in decreased TNBC cell motility. We show that this pathway is mediated by the cyclin-dependent kinase inhibitor p27^kip1 (p27). Indeed, the silencing of HMGA1 expression in TNBC cells results both in an increased p27 protein stability and p27-stathmin binding. When the expression of both HMGA1 and p27 is silenced, we observe a significant rescue in cell motility. These data, obtained in cellular models, were validated in BC patients. In fact, we find that patients with high levels of both HMGA1 and stathmin and low levels of p27 have a statistically significant lower survival probability in terms of relapse-free survival (RFS) and distant metastasis-free survival (DMFS) with respect to the patient group with low HMGA1, low stathmin, and high p27 expression levels. Finally, we show in an in vivo xenograft model that depletion of HMGA1 chemo-sensitizes tumour cells to paclitaxel, a drug that is commonly used in TNBC treatments. This study unveils a new interaction among HMGA1, p27, and stathmin that is critical in BC cell migration. Moreover, our data suggest that taxol-based treatments may be more effective in reducing the tumour burden when tumour cells express low levels of HMGA1.

miR-638 suppresses proliferation by negatively regulating high mobility group A1 in ovarian cancer cells

Ovarian cancer is one of the most common gynecological diseases with high mortality rates. Previous studies have shown that microRNA (miR)-638 is associated with tumorigenesis. The present study aimed to assess the role and underlying mechanisms of miR-638 in ovarian cancer. miR-638 expression was detected in ovarian cancer tissues and miR-638 was overexpressed or knocked down in ovarian cancer OVCAR-3 and Caov-3 cells. The clinical results revealed that miR-638 expression was downregulated in ovarian cancer tissues compared with in adjacent normal tissues. miR-638 expression was also found to be relatively low in OVCAR-3 cells whilst being relatively high in Caov-3 cells among the five ovarian cancer cell lines tested. miR-638 overexpression inhibited cell viability, arrested the cell cycle at the G₁ phase and promoted apoptosis in OVCAR-3 cells. By contrast, miR-638 knockdown increased Caov-3 cell viability, facilitated cell cycle progression and inhibited apoptosis. miR-638 reduced the expression of high mobility group A1 (HMGA1) by directly targeting its 3' untranslated region. HMGA1 overexpression reversed the inhibition of proliferation induced by miR-638 overexpression in OVCAR-3 cells. These results suggest that miR-638 may serve to be a suppressor of ovarian cancer by regulating HMGA1, which may provide a potential therapeutic target for ovarian cancer.

Nucleotide variation in histone H2BL drives crossalk of histone modification and promotes tumour cell proliferation by upregulating c-Myc

Gene mutations play important roles in tumour development. In this study, we identified a functional histone H2B mutation H2BL-T11C, causing an amino acid variation from Leu to Pro (L3P, H2BL-L3P). Cells overexpressing H2BL-L3P showed stronger proliferation, colony formation, tumourigenic abilities, and a different cell cycle distribution. Meanwhile, the c-Myc expression was elevated as evident by RNA-seq. We further revealed that an H2BK5ac-H2BK120ubi crosstalk which regulates gene transcription. Moreover, EdU staining demonstrated an important role of c-Myc in accelerating cell cycle progression through the G1/S checkpoint, while treatment with 10058-F4, an inhibitor of the c-Myc/MAX interaction, alleviated the abnormal cell proliferation and cell cycle distribution in vitro and partially inhibited tumour growth in vivo. The mutation of amino acid L3P is associated with tumour progression, suggesting patients carrying this SNP may have higher risk of tumour development.

Targeting the intrinsically disordered architectural High Mobility Group A (HMGA) oncoproteins in breast cancer: learning from the past to design future strategies

INTRODUCTION

Triple-negative breast cancer (TNBC) is the most difficult breast cancer subtype to treat because of its heterogeneity and lack of specific therapeutic targets. High Mobility Group A (HMGA) proteins are chromatin architectural factors that have multiple oncogenic functions in breast cancer, and they represent promising molecular therapeutic targets for this disease.

AREAS COVERED

We offer an overview of the strategies that have been exploited to counteract HMGA oncoprotein activities at the transcriptional and post-transcriptional levels. We also present the possibility of targeting cancer-associated factors that lie downstream of HMGA proteins and discuss the contribution of HMGA proteins to chemoresistance.

EXPERT OPINION

Different strategies have been exploited to counteract HMGA protein activities; these involve interfering with their nucleic acid binding properties and the blocking of HMGA expression. Some approaches have provided promising results. However, some unique characteristics of the HMGA proteins have not been exploited; these include their extensive protein-protein interaction network and their intrinsically disordered status that present the possibility that HMGA proteins could be involved in the formation of proteinaceous membrane-less organelles (PMLO) by liquid-liquid phase separation. These unexplored characteristics could open new pharmacological avenues to counteract the oncogenic contributions of HMGA proteins.

The Global Phosphorylation Landscape of SARS-CoV-2 Infection

The causative agent of the coronavirus disease 2019 (COVID-19) pandemic, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has infected millions and killed hundreds of thousands of people worldwide, highlighting an urgent need to develop antiviral therapies. Here we present a quantitative mass spectrometry-based phosphoproteomics survey of SARS-CoV-2 infection in Vero E6 cells, revealing dramatic rewiring of phosphorylation on host and viral proteins. SARS-CoV-2 infection promoted casein kinase II (CK2) and p38 MAPK activation, production of diverse cytokines, and shutdown of mitotic kinases, resulting in cell cycle arrest. Infection also stimulated a marked induction of CK2-containing filopodial protrusions possessing budding viral particles. Eighty-seven drugs and compounds were identified by mapping global phosphorylation profiles to dysregulated kinases and pathways. We found pharmacologic inhibition of the p38, CK2, CDK, AXL, and PIKFYVE kinases to possess antiviral efficacy, representing potential COVID-19 therapies.

Mediterranean Diet Nutrients to Turn the Tide against Insulin Resistance and Related Diseases

Insulin resistance (IR), defined as an attenuated biological response to circulating insulin, is a fundamental defect in obesity and type 2 diabetes (T2D), and is also linked to a wide spectrum of pathological conditions, such as non-alcoholic fatty liver disease (NAFLD), cognitive impairment, endothelial dysfunction, chronic kidney disease (CKD), polycystic ovary syndrome (PCOS), and some endocrine tumors, including breast cancer. In obesity, the unbalanced production of pro- and anti-inflammatory adipocytokines can lead to the development of IR and its related metabolic complications, which are potentially reversible through weight-loss programs. The Mediterranean diet (MedDiet), characterized by high consumption of extra-virgin olive oil (EVOO), nuts, red wine, vegetables and other polyphenol-rich elements, has proved to be associated with greater improvement of IR in obese individuals, when compared to other nutritional interventions. Also, recent studies in either experimental animal models or in humans, have shown encouraging results for insulin-sensitizing nutritional supplements derived from MedDiet food sources in the modulation of pathognomonic traits of certain IR-related conditions, including polyunsaturated fatty acids from olive oil and seeds, anthocyanins from purple vegetables and fruits, resveratrol from grapes, and the EVOO-derived, oleacein. Although the pharmacological properties and clinical uses of these functional nutrients are still under investigation, the molecular mechanism(s) underlying the metabolic benefits appear to be compound-specific and, in some cases, point to a role in gene expression through an involvement of the nuclear high-mobility group A1 (HMGA1) protein.

Long noncoding RNA LINC00963 promotes breast cancer progression by functioning as a molecular sponge for microRNA-625 and thereby upregulating HMGA1

Extensive research has shown that LINC00963 is aberrantly expressed in human cancers, and that dysregulation of LINC00963 is implicated in the initiation and progression of human cancers. The expression and functions of LINC00963 in breast cancer are still unclear. Our aims were to measure the expression of LINC00963 in breast cancer, determine its effects on malignant behaviors of tumor cells, and uncover the molecular events underlying the actions of LINC00963 in breast cancer. Herein, LINC00963 was found to be overexpressed in breast cancer samples, and its overexpression was correlated with lymph node metastasis, TNM stage and differentiation grade. Patients with breast cancer harboring higher LINC00963 expression showed shorter overall survival than did the patients with lower LINC00963 expression. Functional experiments revealed that depletion of LINC00963 inhibited breast cancer cell proliferation, migration, and invasion and facilitated apoptosis in vitro and impaired tumor growth in vivo. Mechanism investigation revealed that LINC00963 can interact with microRNA-625 (miR-625). LINC00963 worked as a competitive endogenous RNA for miR-625 to weaken the suppressive effect of miR-625 on high mobility group AT-hook 1 (HMGA1) in breast cancer cells. Furthermore, miR-625 inhibition and HMGA1 restoration both abrogated the effects of LINC00963 silencing on breast cancer cells. Our findings indicate that the LINC00963-miR-625-HMGA1 pathway plays an important role in the malignancy of breast cancer in vitro and in vivo. Hence, targeting this pathway may be a novel strategy against breast cancer.

HMGA2 Antisense Long Non-coding RNAs as New Players in the Regulation of HMGA2 Expression and Pancreatic Cancer Promotion

Background: Natural antisense long non-coding RNAs (lncRNAs) are regulatory RNAs transcribed from the opposite strand of either protein coding or non-coding genes, able to modulate their own sense gene expression. Hence, their dysregulation can lead to pathologic processes. Cancer is a complex class of diseases determined by the aberrant expression of a variety of factors, among them, the oncofetal chromatin architectural proteins High Mobility Group A (HMGA) modulate several cancer hallmarks. Thus, we decided to investigate the presence of natural antisense lncRNAs in HMGA1 and HMGA2 loci, and their possible involvement in gene expression regulation. Methods: We used FANTOM5 data resources, FANTOM-CAT genome browser and Zenbu visualization tool, which employ 1,829 human CAGE and RNA-sequencing libraries, to determine expression, ontology enrichment, and dynamic regulation of natural antisense lncRNAs in HMGA1 and HMGA2 loci. We then performed qRT-PCR in different cancer cell lines to validate the existence of HMGA2-AS1 transcripts. We depleted HMGA2-AS1 transcripts with siRNAs and investigated HMGA2 expression by qRT-PCR and western blot analyses. Moreover, we evaluated cell viability and migration by MTS and transwell assays, and EMT markers by qRT-PCR and immunofluorescence. Furthermore, we used bioinformatics approaches to evaluate HMGA2 and HMGA2-AS1 correlation and overall survival in tumor patients. Results: We found the presence of a promoter-associated lncRNA (CATG00000088127.1) in the HMGA1 gene and three antisense genes (RPSAP52, HMGA2-AS1, and RP11-366L20.3) in the HMGA2 gene. We studied the uncharacterized HMGA2-AS1 transcripts, validating their existence in cancer cell lines and observing a positive correlation between HMGA2 and HMGA2-AS1 expression in a cancer-derived patient dataset. We showed that HMGA2-AS1 transcripts positively modulate HMGA2 expression and migration properties of PANC1 cells through HMGA2. In addition, Kaplan-Meier analysis showed that high level of HMGA2-AS1 is a negative prognostic factor in pancreatic cancer patients. Conclusions: Our results describe novel antisense lncRNAs associated with HMGA1 and HMGA2 genes. In particular, we demonstrate that HMGA2-AS1 is involved in the regulation of its own sense gene expression, mediating tumorigenesis. Thus, we highlight a new layer of complexity in the regulation of HMGA2 expression, providing new potential targets for cancer therapy.