PSPC1 Potentiates IGF1R Expression to Augment Cell Adhesion and Motility

IGF-1R mediates crosstalk between nasopharyngeal carcinoma cells and osteoclasts and promotes tumor bone metastasis

BACKGROUND

Nasopharyngeal carcinoma (NPC) poses a significant health burden in specific regions of Asia, and some of NPC patients have bone metastases at the time of initial diagnosis. Bone metastasis can cause pathologic fractures and pain, reducing patients' quality of life, and is associated with worse survival. This study aims to unravel the complex role of insulin-like growth factor 1 receptor (IGF-1R) in NPC bone metastasis, offering insights into potential therapeutic targets.

METHODS

We assessed IGF-1R expression in NPC cells and explored its correlation with bone metastasis. Experiments investigated the impact of osteoclast-secreted IGF-1 on the IGF-1R/AKT/S6 pathway in promoting NPC cell proliferation within the bone marrow. Additionally, the reciprocal influence of tumor-secreted Granulocyte-macrophage colony-stimulating factor (GM-CSF) on osteoclast differentiation and bone resorption was examined. The effects of IGF-1 neutralizing antibody, IGF-1R specific inhibitor (NVP-AEW541) and mTORC inhibitor (rapamycin) on nasopharyngeal carcinoma bone metastasis were also explored in animal experiments.

RESULTS

Elevated IGF-1R expression in NPC cells correlated with an increased tendency for bone metastasis. IGF-1, secreted by osteoclasts, activated the IGF-1R/AKT/S6 pathway, promoting NPC cell proliferation in the bone marrow. Tumor-secreted GM-CSF further stimulated osteoclast differentiation, exacerbating bone resorption. The IGF-1 neutralizing antibody, NVP-AEW541 and rapamycin were respectively effective in slowing down the rate of bone metastasis and reducing bone destruction.

CONCLUSION

The intricate interplay among IGF-1R, IGF-1, and GM-CSF highlights potential therapeutic targets for precise control of NPC bone metastasis, providing valuable insights for developing targeted interventions.

PSPC1 Inhibition Synergizes with Poly(ADP-ribose) Polymerase Inhibitors in a Preclinical Model of BRCA-Mutated Breast/Ovarian Cancer

Poly (ADP-ribose) polymerase (PARP) inhibitors are effective against BRCA1/2-mutated cancers through synthetic lethality. Unfortunately, most cases ultimately develop acquired resistance. Therefore, enhancing PARP inhibitor sensitivity and preventing resistance in those cells are an unmet clinical need. Here, we investigated the ability of paraspeckle component 1 (PSPC1), as an additional synthetic lethal partner with BRCA1/2, to enhance olaparib sensitivity in preclinical models of BRCA1/2-mutated breast and ovarian cancers. In vitro, the combined olaparib and PSPC1 small interfering RNA (siRNA) exhibited synergistic anti-proliferative activity in BRCA1/2-mutated breast and ovarian cancer cells. The combination therapy also demonstrated synergistic tumor inhibition in a xenograft mouse model. Mechanistically, olaparib monotherapy increased the expressions of p-ATM and DNA-PKcs, suggesting the activation of a DNA repair pathway, whereas combining PSPC1 siRNA with olaparib decreased the expressions of p-ATM and DNA-PKcs again. As such, the combination increased the formation of γH2AX foci, indicating stronger DNA double-strand breaks. Subsequently, these DNA-damaged cells escaped G2/M checkpoint activation, as indicated by the suppression of p-cdc25C (Ser216) and p-cdc2 (Tyr15) after combination treatment. Finally, these cells entered mitosis, which induced increased apoptosis. Thus, this proves that PSPC1 inhibition enhances olaparib sensitivity by targeting DNA damage response in our preclinical model. The combination of olaparib and PSPC1 inhibition merits further clinical investigation to enhance PARP inhibitor efficacy.

Hsa_circ_0003596 enhances the development of cell renal clear cell carcinoma through the miR-502-5p/IGF1/PI3K/AKT axis

Accumulating research findings have shown that circular RNAs (circRNAs) play an indispensable role in tumorigenesis and tumor progression. The current study aimed to explore the role and modulatory mechanism of hsa_circ_0003596 in clear cell renal cell carcinoma (ccRCC). Quantitative real-time polymerase chain reaction was adopted to detect the expression of hsa_circ_0003596 in ccRCC tissue and cell lines. 5-Ethynyl-2'-deoxyuridine, cell counting kit 8 and the colony formation assay were utilized to assess the proliferation potential of the ccRCC cells. Transwell along with wound healing assays were adopted to quantify infiltration coupled with the migration potential of the cells. The current research study found that the circRNA hsa_circ_0003596 was overexpressed in ccRCC tissue and cell lines. Further, result showed that hsa_circ_0003596 was associated with distant metastasis of renal cancer. Notably, the knockdown of hsa_circ_0003596 can lower the proliferation, infiltration and migration potential of ccRCC cells. The results of in vivo experiments found that the reduction of hsa_circ_0003596 significantly hampered the growth of tumors in mice. In addition, it was evident that hsa_circ_0003596 acts as a "molecular sponge" for miR-502-5p to upregulate the expression of the microRNA-502-5p (miR-502-5p) target insulin-like growth factor 1 (IGF1R). Furthermore, it was found that the phosphatidylinositol 3-kinase (PI3K)/AKT signaling was the downstream cascade of hsa_circ_0003596/miR-502-5p/IGF1R cascade, which is partly responsible for the cancer-promoting effect. Overall, the results of the present study showed that hsa_circ_0003596 facilitated the proliferation, infiltration and migration of ccRCC through the miR-502-5p/IGF1R/PI3K/AKT axis. Therefore, it was evident that hsa_circ_0003596 can serve as a possible biomarker and therapeutic target against ccRCC.

Elevated PSPC1 and KDM5C expression indicates poor prognosis in prostate cancer

Prostate cancer (PCa) remains the most commonly diagnosed cancer in men worldwide and is still the second leading cause of cancer-related death. One major cause of PCa development is epigenetic aberration, including histone modification. We have previously demonstrated that Lysine Demethylase 5C (KDM5C) plays an essential role in the development of PCa and drives PCa progression by promoting epithelial-mesenchymal transition. Epigenetic regulators often work in concert, for example, to regulate transcription. We identified Paraspeckle Component 1 (PSPC1) as an interacting protein of KDM5C, suggesting that these proteins might function together in PCa. Here, we systematically investigate the expression patterns of KDM5C and PSPC1 in 2 independent prostate cohorts (432 and 205 prostate tumors in total for PSPC1 and KDM5C, respectively) by immunohistochemistry. We demonstrate that the expression of PSPC1 correlates with that of KDM5C. In addition, PSPC1 is up-regulated in primary and metastatic PCa. Elevated PSPC1 expression correlates with a higher-grade group and an advanced T-stage. Patients with high PSPC1 expression have a worse biochemical recurrence-free survival. In addition, PSPC1 expression is an independent prognostic parameter. Our data indicate that KDM5C and PSPC1 are involved in PCa progression, and therapeutic inhibition of KDM5C and PSPC1 by selective compounds might be a promising approach for the treatment of PCa.

Molecular Interactions of the Long Noncoding RNA NEAT1 in Cancer

As one of the best-studied long noncoding RNAs, nuclear paraspeckle assembly transcript 1 (NEAT1) plays a pivotal role in the progression of cancers. NEAT1, especially its isoform NEAT1-1, facilitates the growth and metastasis of various cancers, excluding acute promyelocytic leukemia. NEAT1 can be elevated via transcriptional activation or stability alteration in cancers changing the aggressive phenotype of cancer cells. NEAT1 can also be secreted from other cells and be delivered to cancer cells through exosomes. Hence, elucidating the molecular interaction of NEAT1 may shed light on the future treatment of cancer. Herein, we review the molecular function of NEAT1 in cancer progression, and explain how NEAT1 interacts with RNAs, proteins, and DNA promoter regions to upregulate tumorigenic factors.

Long noncoding RNA NEAT1 changes exosome secretion and microRNA expression carried by exosomes in hepatocellular carcinoma cells

BACKGROUND

This study aimed to investigate the roles and functions of nuclear-enriched abundant transcript 1 (NEAT1) in exosome secretion and exosomal microRNA (miRNA) changes in hepatocellular carcinoma (HCC) cells.

METHODS

HepG2 and HuH-7 cells were divided into two groups: Lv-control (which were infected with lentivirus without NEAT1 expression) and Lv-NEAT1 (which were infected with lentivirus with NEAT1 overexpression). Each group was used to study cell function (proliferation, invasion, and apoptosis) and exosome secretion by nanoparticle tracking analysis (NTA), electron microscopy, and nanoflow cytometry (nanoFCM). Different levels of messenger RNA (mRNA), miRNA, and exosomal miRNA were detected by RNA sequencing. Next, potential target RNAs were verified by reverse transcription polymerase chain reaction (RT-PCR). Changed exosomal miRNAs were found and miRNA mimics were used to study cell function in NEAT1-overexpression and NEAT1-knockdown HCC cells.

RESULTS

The data showed that NEAT1-overexpression promoted exosome secretion. The overexpression of NEAT1 altered global genes, including exosome-related genes. Compared with the control group, we observed that several miRNAs changed in the exosomes secreted by NEAT1-overexpressing cells. Our study found that these changed exosomal miRNAs played a suppressor role in HCC. Transfection of miR-634, miR-638, and miR-3960 reversed the enhanced invasion and proliferation in HCC cells with a high level of NEAT1 expression.

CONCLUSIONS

These results suggested that NEAT1 regulates exosome-related genes, which might be associated with increasing exosome secretion by NEAT1-overexpressing cells. Furthermore, NEAT1 promotes cell invasion and proliferation via downregulation of miR-634, miR-638, and miR-3960 in exosomes. This study may provide potential targets for exosome-mediated miRNA transfer in HCCs with a high level of NEAT1 expression therapy.

PSPC1 is a new contextual determinant of aberrant subcellular translocation of oncogenes in tumor progression

Dysregulation of nucleocytoplasmic shuttling is commonly observed in cancers and emerging as a cancer hallmark for the development of anticancer therapeutic strategies. Despite its severe adverse effects, selinexor, a selective first-in-class inhibitor of the common nuclear export receptor XPO1, was developed to target nucleocytoplasmic protein shuttling and received accelerated FDA approval in 2019 in combination with dexamethasone as a fifth-line therapeutic option for adults with relapsed refractory multiple myeloma (RRMM). To explore innovative targets in nucleocytoplasmic shuttling, we propose that the aberrant contextual determinants of nucleocytoplasmic shuttling, such as PSPC1 (Paraspeckle component 1), TGIF1 (TGF-β Induced Factor Homeobox 1), NPM1 (Nucleophosmin), Mortalin and EBP50, that modulate shuttling (or cargo) proteins with opposite tumorigenic functions in different subcellular locations could be theranostic targets for developing anticancer strategies. For instance, PSPC1 was recently shown to be the contextual determinant of the TGF-β prometastatic switch and PTK6/β-catenin reciprocal oncogenic nucleocytoplasmic shuttling during hepatocellular carcinoma (HCC) progression. The innovative nucleocytoplasmic shuttling inhibitor PSPC1 C-terminal 131 polypeptide (PSPC1-CT131), which was developed to target both the shuttling determinant PSPC1 and the shuttling protein PTK6, maintained their tumor-suppressive characteristics and exhibited synergistic effects on tumor suppression in HCC cells and mouse models. In summary, targeting the contextual determinants of nucleocytoplasmic shuttling with cargo proteins having opposite tumorigenic functions in different subcellular locations could be an innovative strategy for developing new therapeutic biomarkers and agents to improve cancer therapy.

Intermittent Hypoxia Mediates Paraspeckle Protein-1 Upregulation in Sleep Apnea

Simple Summary

Patients with obstructive sleep apnea (OSA) exhibit an intermittent hypoxia-dependent paraspeckle protein-1 (PSPC1) increase, which is eventually delivered to the plasma through its cleavage from OSA monocytes by matrix metalloprotease-2, promoting tumor growth factor (TGFβ) expression and increasing epithelial-to-mesenchymal transition in a tumor functional model using a melanoma cell line. These results connect the phenomena of sleep apnea with increased plasma PSPC1 levels, which has a functional effect on the TGFβ pathway and accelerates tumor progression.

Abstract

As some evidence suggests that hypoxia might be an inducer of nuclear paraspeckle formation, we explore whether intermittent hypoxia (IH)-mediated paraspeckle protein-1 (PSPC1) overexpression might contribute to the activation of tumor growth factor (TGF)β-SMAD pathway in patients with obstructive sleep apnea (OSA). This activation would promote changes in intracellular signaling that would explain the increased cancer aggressiveness reported in these patients. Here, we show that patients with OSA exhibit elevated PSPC1 levels both in plasma and in monocytes. Our data suggest that PSPC1 is ultimately delivered to the plasma through its cleavage from OSA monocytes by matrix metalloproteinase-2 (MMP2). In addition, IH promotes PSPC1, TGFβ, and MMP2 expression in monocytes through the hypoxia-inducible factor. Lastly, both PSPC1 and TGFβ induce increased expression of genes that drive the epithelial-to-mesenchymal transition. Our study details the mechanism by which hypoxemia upmodulates the extracellular release of PSPC1 by means of MMP2, such that plasma PSPC1 together with TGFβ activation signaling further promotes tumor metastasis and supports cancer aggressiveness in patients with OSA.

Proteomic Profiling and Artificial Intelligence for Hepatocellular Carcinoma Translational Medicine

Hepatocellular carcinoma (HCC) is the most common primary cancer of the liver with high morbidity and mortality rates worldwide. Since 1963, when alpha-fetoprotein (AFP) was discovered as a first HCC serum biomarker, several other protein biomarkers have been identified and introduced into clinical practice. However, insufficient specificity and sensitivity of these biomarkers dictate the necessity of novel biomarker discovery. Remarkable advancements in integrated multiomics technologies for the identification of gene expression and protein or metabolite distribution patterns can facilitate rising to this challenge. Current multiomics technologies lead to the accumulation of a huge amount of data, which requires clustering and finding correlations between various datasets and developing predictive models for data filtering, pre-processing, and reducing dimensionality. Artificial intelligence (AI) technologies have an enormous potential to overcome accelerated data growth, complexity, and heterogeneity within and across data sources. Our review focuses on the recent progress in integrative proteomic profiling strategies and their usage in combination with machine learning and deep learning technologies for the discovery of novel biomarker candidates for HCC early diagnosis and prognosis. We discuss conventional and promising proteomic biomarkers of HCC such as AFP, lens culinaris agglutinin (LCA)-reactive L3 glycoform of AFP (AFP-L3), des-gamma-carboxyprothrombin (DCP), osteopontin (OPN), glypican-3 (GPC3), dickkopf-1 (DKK1), midkine (MDK), and squamous cell carcinoma antigen (SCCA) and highlight their functional significance including the involvement in cell signaling such as Wnt/β-catenin, PI3K/Akt, integrin αvβ3/NF-κB/HIF-1α, JAK/STAT3 and MAPK/ERK-mediated pathways dysregulated in HCC. We show that currently available computational platforms for big data analysis and AI technologies can both enhance proteomic profiling and improve imaging techniques to enhance the translational application of proteomics data into precision medicine.