The LEDGF/p75 Integrase Binding Domain Interactome Contributes to the Survival, Clonogenicity, and Tumorsphere Formation of Docetaxel-Resistant Prostate Cancer Cells

CircRNA-mTOR Promotes Hepatocellular Carcinoma Progression and Lenvatinib Resistance Through the PSIP1/c-Myc Axis

Circular RNAs (circRNAs) are crucial regulators of targeted drug resistance in hepatocellular carcinoma (HCC). However, the specific mechanisms underlying resistance that significantly hampers the effectiveness of HCC treatments remain unclear. Here, it is found that circRNA-mTOR is highly expressed in HCC and strongly correlated with patient prognosis. Furthermore, circRNA-mTOR enhances the stemness of HCC cells, thereby promoting the progression of HCC and contributing to lenvatinib resistance. Mechanistically, circRNA-mTOR promotes the nuclear translocation of the RNA-binding protein (RBP) PC4 and SRSF1 interacting protein 1 (PSIP1) through specific binding. The enhancement of HCC cell stemness by circRNA-mTOR occurs via the PSIP1/c-Myc signaling pathway, ultimately driving HCC progression and lenvatinib resistance. This study highlights the important role of circRNA-mTOR in HCC progression and the maintenance of lenvatinib resistance and underscores its potential as a biomarker for the diagnosis and prognosis of HCC. In conclusion, this study provides an experimental foundation for targeted drug therapy in HCC and offers novel insights, perspectives, and methodologies for understanding the development and occurrence of this disease. These findings are significant for the development of new diagnostic and therapeutic markers for HCC, with the ultimate goal of reducing drug resistance.

POGZ targeted by LINC01355/miR-27b-3p retards thyroid cancer progression via interplaying with MAD2L2

Despite the high morbidity of thyroid cancer (THCA), the underlying molecular pathology remains elusive. That autism-associated protein POGZ has recently been involved in tumorigenesis intrigues us exploring its relevant molecular regulatory network in THCA. Clinical characteristics and intermolecular relationships were dissected by bioinformatics. Interaction between POGZ and MAD2L2 was examined by Co-IP assay. Targeting relationships between miR-27b-3p and POGZ/LINC01355 was verified by sequence prediction and dual-luciferase reporter detection. Cellular effects of genes were assessed by CCK-8 assay, clone formation assay, and Transwell assay, and further confirmed by a tumor-bearing nude mice model. Our results demonstrated a decrease in POGZ expression in THCA tissues and cell lines, and an interaction between POGZ and MAD2L2 protein. POGZ inhibited both the proliferation and motility of THCA cells, with these effects being reversed upon MAD2L2 silencing. LINC01355 exhibited low expression level and a positive correlation with POGZ in THCA. Both miR-27b-3p and LINC01355 were identified as regulators of POGZ through targeting. Elevated miR-27b-3p suppressed POGZ expression. LINC01355 promoted POGZ and counteracted the inhibitory effects of miR-27b-3p. Furthermore, miR-27b-3p increased the proliferation and motility of THCA cells, an effect that was blocked by LINC01355. At the animal level, POGZ, LINC01355, and MAD2L2 all attenuated tumor growth in THCA. Collectively, POGZ restrains THCA growth by interacting with MAD2L2 protein, and POGZ modulation involves a complex interplay orchestrated by LINC01355-targeted miR-27b-3p. By reporting the first POGZ-focused ceRNA network involving noncoding RNA in THCA, our study paves the way for exploring POGZ-related pathways and developing new therapeutic strategies in cancer.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-025-04231-7.

Role of LEDGF/p75 (PSIP1) in oncogenesis. Insights in molecular mechanism and therapeutic potential

Aberrant gene expression due to dysfunction in proteins involved in transcriptional regulation is a hallmark of tumor development. Indeed, targeting transcriptional regulators represents an emerging approach in cancer therapeutics. Lens epithelium-derived growth factor (LEDGF/p75, PSIP1) is a co-transcriptional activator that tethers several proteins to the chromatin. LEDGF/p75 has been implicated in diseases such as HIV infection and KMT2A-rearranged leukemia. Notably, LEDGF/p75 is upregulated in various human cancers including prostate and breast cancer. In this review, we discuss the essential role of LEDGF/p75 in different malignancies and explore its mechanistic contribution to tumorigenesis revealing its potential as a therapeutic target for chemotherapy.

PSIP1 promotes gefitinib resistance in lung adenocarcinoma by inducing the expression of WASF3 and its downstream ITGB3/AKT signaling

BACKGROUND

Gefitinib (GR), a representative drug of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), is a key pillar in the treatment of lung adenocarcinoma (LUAD), but drug resistance is universal. Identifying the potential factors of drug resistance to GR is essential to treat patients with EGFR mutant LUAD.

METHODS

The GR-resistant LUAD cells were established and confirmed by MTT assay. The effects of PC4 and SRSF1 interacting protein 1 (PSIP1) on GR-resistant cell proliferation and apoptosis in vitro and in vivo were detected by colony formation, flow cytometry, tumor-bearing animal model, immunohistochemistry, and TUNEL staining. Western blotting and qPCR were used to determine the expression of relevant markers. The effect of PSIP1 on the promoter region of Wiskott-Aldrich syndrome protein family member 3 (WASF3) was detected by the dual-luciferase assay. The interaction between PSIP1 and RNA polymerase II was evaluated using ChIP-qPCR and Co-IP assays.

RESULTS

PSIP1 was highly enriched in GR-resistant LUAD cells. Downregulation of PSIP1 expression significantly inhibited the proliferation of LUAD-resistant cells and promoted apoptosis. WASF3 was shown to have similar effects as PSIP1 in promoting drug resistance in LUAD cells. PSIP1 promoted the transcriptional activity of WASF3, which was achieved by increasing RNA polymerase II recruitment on the WASF3 promoter. Furthermore, PSIP1 positively regulated the expression of the pro-EGFR-TKI resistance factor integrin subunit beta 3 (ITGB3).

CONCLUSION

Our work suggests that PSIP1 promotes resistance to GR in LUAD cells by inducing the expression of WASF3 and its downstream regulator ITGB3.

The Emerging Roles of the Stress Epigenetic Reader LEDGF/p75 in Cancer Biology and Therapy Resistance: Mechanisms and Targeting Opportunities

The lens epithelium derived growth factor of 75 kD (LEDGF/p75) is a transcription co-activator and epigenetic reader that has emerged as a stress oncoprotein in multiple human cancers. Growing evidence indicates that it promotes tumor cell survival against certain therapeutic drugs. The amino (N)-terminal region of LEDGF/p75 contains a PWWP domain that reads methylated histone marks, critical for recognizing transcriptionally active chromatin sites. Its carboxyl (C)-terminus has an integrase binding domain (IBD) that serves as the binding site for the HIV-1 integrase and multiple oncogenic transcription factors. Acting as hubs for protein-protein interactions, both domains facilitate the tethering of oncogenic transcription factors and regulators to active chromatin to regulate mRNA splicing, promote DNA repair, and enhance the expression of stress and cancer-related genes that contribute to tumor cell aggressiveness and chemoresistance. This review summarizes our current knowledge of the emerging roles of LEDGF/p75 in cancer biology and therapy resistance and discusses its potential as a novel oncotherapeutic target in combinatorial treatments.

The Impact of Lens Epithelium-Derived Growth Factor p75 Dimerization on Its Tethering Function

The transcriptional co-activator lens epithelium-derived growth factor/p75 (LEDGF/p75) plays an important role in the biology of the cell and in several human diseases, including MLL-rearranged acute leukemia, autoimmunity, and HIV-1 infection. In both health and disease, LEDGF/p75 functions as a chromatin tether that interacts with proteins such as MLL1 and HIV-1 integrase via its integrase-binding domain (IBD) and with chromatin through its N-terminal PWWP domain. Recently, dimerization of LEDGF/p75 was shown, mediated by a network of electrostatic contacts between amino acids from the IBD and the C-terminal α6-helix. Here, we investigated the functional impact of LEDGF/p75 variants on the dimerization using biochemical and cellular interaction assays. The data demonstrate that the C-terminal α6-helix folds back in cis on the IBD of monomeric LEDGF/p75. We discovered that the presence of DNA stimulates LEDGF/p75 dimerization. LEDGF/p75 dimerization enhances binding to MLL1 but not to HIV-1 integrase, a finding that was observed in vitro and validated in cell culture. Whereas HIV-1 replication was not dependent on LEDGF/p75 dimerization, colony formation of MLLr-dependent human leukemic THP-1 cells was. In conclusion, our data indicate that intricate changes in the quaternary structure of LEDGF/p75 modulate its tethering function.

Identification of the H3K36me3 reader LEDGF/p75 in the pancancer landscape and functional exploration in clear cell renal cell carcinoma

Lens epithelium-derived growth factor (LEDGF/p75) is a reader of epigenetic marks and a potential target for therapeutic intervention. Its involvement in human immunodeficiency virus (HIV) integration and the development of leukemia driven by MLL (also known as KMT2A) gene fusion make it an attractive candidate for drug development. However, exploration of LEDGF/p75 as an epigenetic reader of H3K36me3 in tumors is limited. Here, for the first time, we analyze the role of LEDGF/p75 in multiple cancers via multiple online databases and in vitro experiments. We used pancancer bulk sequencing data and online tools to analyze correlations of LEDGF/p75 with prognosis, genomic instability, DNA damage repair, prognostic alternative splicing, protein interactions, and tumor immunity. In summary, the present study identified that LEDGF/p75 may serve as a prognostic predictor for tumors such as adrenocortical carcinoma, kidney chromophobe, liver hepatocellular carcinoma, pancreatic adenocarcinoma, skin cutaneous melanoma, and clear cell renal cell carcinoma (ccRCC). In addition, in vitro experiments and gene microarray sequencing were performed to explore the function of LEDGF/p75 in ccRCC, providing new insights into the pathogenesis of the nonmutated SETD2 ccRCC subtype.

Glucocorticoid Receptor Regulates and Interacts with LEDGF/p75 to Promote Docetaxel Resistance in Prostate Cancer Cells

Patients with advanced prostate cancer (PCa) invariably develop resistance to anti-androgen therapy and taxane-based chemotherapy. Glucocorticoid receptor (GR) has been implicated in PCa therapy resistance; however, the mechanisms underlying GR-mediated chemoresistance remain unclear. Lens epithelium-derived growth factor p75 (LEDGF/p75, also known as PSIP1 and DFS70) is a glucocorticoid-induced transcription co-activator implicated in cancer chemoresistance. We investigated the contribution of the GR-LEDGF/p75 axis to docetaxel (DTX)-resistance in PCa cells. GR silencing in DTX-sensitive and -resistant PCa cells decreased LEDGF/p75 expression, and GR upregulation in enzalutamide-resistant cells correlated with increased LEDGF/p75 expression. ChIP-sequencing revealed GR binding sites in the LEDGF/p75 promoter. STRING protein-protein interaction analysis indicated that GR and LEDGF/p75 belong to the same transcriptional network, and immunochemical studies demonstrated their co-immunoprecipitation and co-localization in DTX-resistant cells. The GR modulators exicorilant and relacorilant increased the sensitivity of chemoresistant PCa cells to DTX-induced cell death, and this effect was more pronounced upon LEDGF/p75 silencing. RNA-sequencing of DTX-resistant cells with GR or LEDGF/p75 knockdown revealed a transcriptomic overlap targeting signaling pathways associated with cell survival and proliferation, cancer, and therapy resistance. These studies implicate the GR-LEDGF/p75 axis in PCa therapy resistance and provide a pre-clinical rationale for developing novel therapeutic strategies for advanced PCa.

Glucocorticoid Receptor and β-Catenin Interact in Prostate Cancer Cells and Their Co-Inhibition Attenuates Tumorsphere Formation, Stemness, and Docetaxel Resistance

Therapy resistance hinders the efficacy of anti-androgen therapies and taxane-based chemotherapy for advanced prostate cancer (PCa). Glucocorticoid receptor (GR) signaling mediates resistance to androgen receptor signaling inhibitors (ARSI) and has also been recently implicated in PCa resistance to docetaxel (DTX), suggesting a role in therapy cross-resistance. Like GR, β-catenin is upregulated in metastatic and therapy-resistant tumors and is a crucial regulator of cancer stemness and ARSI resistance. β-catenin interacts with AR to promote PCa progression. Given the structural and functional similarities between AR and GR, we hypothesized that β-catenin also interacts with GR to influence PCa stemness and chemoresistance. As expected, we observed that treatment with the glucocorticoid dexamethasone promotednuclear accumulation of GR and active β-catenin in PCa cells. Co-immunoprecipitation studies showed that GR and β-catenin interact in DTX-resistant and DTX-sensitive PCa cells. Pharmacological co-inhibition of GR and β-catenin, using the GR modulator CORT-108297 and the selective β-catenin inhibitor MSAB, enhanced cytotoxicity in DTX-resistant PCa cells grown in adherent and spheroid cultures and decreased CD44+/CD24- cell populations in tumorspheres. These results indicate that GR and β-catenin influence cell survival, stemness, and tumorsphere formation in DTX-resistant cells. Their co-inhibition could be a promising therapeutic strategy to overcome PCa therapy cross-resistance.

The Nuclear Dense Fine Speckled (DFS) Immunofluorescence Pattern: Not All Roads Lead to DFS70/LEDGFp75

The monospecific dense fine speckled (DFS) immunofluorescence assay (IFA) pattern is considered a potential marker to aid in exclusion of antinuclear antibody (ANA)-associated rheumatic diseases (AARD). This pattern is typically produced by autoantibodies against transcription co-activator DFS70/LEDGFp75, which are frequently found in healthy individuals and patients with miscellaneous inflammatory conditions. In AARD patients, these antibodies usually co-exist with disease-associated ANAs. Previous studies reported the occurrence of monospecific autoantibodies that generate a DFS-like or pseudo-DFS IFA pattern but do not react with DFS70/LEDGFp75. We characterized this pattern using confocal microscopy and immunoblotting. The target antigen associated with this pattern partially co-localized with DFS70/LEDGFp75 and its interacting partners H3K36me2, an active chromatin marker, and MLL, a transcription factor, in HEp-2 cells, suggesting a role in transcription. Immunoblotting did not reveal a common protein band immunoreactive with antibodies producing the pseudo-DFS pattern, suggesting they may recognize diverse proteins or conformational epitopes. Given the subjectivity of the HEp-2 IFA test, the awareness of pseudo-DFS autoantibodies reinforces recommendations for confirmatory testing when reporting patient antibodies producing a putative DFS pattern in a clinical setting. Future studies should focus on defining the potential diagnostic utility of the pseudo-DFS pattern and its associated antigen(s).

An Overview of 10th Anniversary of Cells-Advances in Cell Nuclei: Function, Transport and Receptors

The year 2021 marked the 10^th anniversary of the publication of Cells [...].

Circulating miR-1246 and miR-485-3p as Promising Biomarkers of Clinical Response and Outcome in Melanoma Patients Treated with Targeted Therapy

Despite the significant improvements in advanced melanoma therapy, there is still a pressing need for biomarkers that can predict patient response and prognosis, and therefore support rational treatment decisions. Here, we investigated whether circulating miRNAs could be biomarkers of clinical outcomes in patients treated with targeted therapy. Using next-generation sequencing, we profiled plasma miRNAs at baseline and at progression in patients treated with BRAF inhibitors (BRAFi) or BRAFi + MEKi. Selected miRNAs associated with response to therapy were subjected to validation by real-time quantitative RT-PCR . Receiver Operating Characteristics (ROC), Kaplan–Meier and univariate and multivariate Cox regression analyses were performed on the validated miR-1246 and miR-485-3p baseline levels. The median baseline levels of miR-1246 and miR-485-3p were significantly higher and lower, respectively, in the group of patients not responding to therapy (NRs) as compared with the group of responding patients (Rs). In Rs, a trend toward an increase in miR-1246 and a decrease in miR-485-3p was observed at progression. Baseline miR-1246 level and the miR-1246/miR-485-3p ratio showed a good ability to discriminate between Rs and NRs. Poorer PFS and OS were observed in patients with unfavorable levels of at least one miRNA. In multivariate analysis, a low level of miR-485-3p and a high miR-1246/miR-485-3p ratio remained independent negative prognostic factors for PFS, while a high miR-1246/miR-485-3p ratio was associated with an increased risk of mortality, although statistical significance was not reached. Evaluation of miR-1246 and miR-485-3p baseline plasma levels might help clinicians to identify melanoma patients most likely to be unresponsive to targeted therapy or at higher risk for short-term PFS and mortality, thus improving their management.