Pancreatic Cancer Progression Is Regulated by IPO7/p53/LncRNA MALAT1/MiR-129-5p Positive Feedback Loop

LncRNA MALAT1-Targeting Antisense Oligonucleotide Ameliorates the AngII-Induced Vascular Smooth Muscle Cell Proliferation and Migration Through Nrf2/GPX4 Antioxidant Pathway

ABSTRACT

The high level of oxidative stress induced by angiotensin II (AngII) is the main pathophysiological process that promotes the proliferation and migration of vascular smooth muscle cells (VSMCs) and induces vascular remodeling. LncRNA metastasis-related lung adenocarcinoma transcript 1 (MALAT1) has been determined to play an important role in the modulation of oxidative stress and the development of cardiovascular diseases. Nevertheless, the function and underlying mechanism of MALAT1 in restenosis induced by hypertensive angioplasty remain unclear. AngII increased the expression of MALAT1 in VSMCs. We found that antisense oligonucleotide lncRNA MALAT1 (ASO-MALAT1) could inhibit AngII-induced reactive oxygen species production and VSMCs proliferation and migration by inducing the expression of glutathione peroxidase 4 (GPX4), which can be reversed by siRNA-GPX4. GPX4 overexpression can inhibit the proliferation and migration of VSMCs induced by AngII. In addition, we found that the process by which MALAT1 knockdown induces GPX4 expression involves nuclear factor erythrocyte 2-related factor 2 (Nrf2). Overexpression of Nrf2 can increase the expression of GPX4, and downregulation of GPX4 by ML385 (Nrf2 inhibitor) blocked the protective effect of ASO-MALAT1 on AngII-induced proliferation and migration of VSMCs. Ferrostatin-1 (Fer-1, ip 5 mg/kg per day for 2 weeks), a GPX4 agonist, significantly inhibited neointimal formation in spontaneously hypertensive rat by the inhibition of oxidative stress. In conclusion, these data imply that ASO-MALAT1 suppresses the AngII-induced oxidative stress, proliferation, and migration of VSMCs by activating Nrf2/GPX4 antioxidant signaling. GPX4 may be a potential target for the therapeutic intervention of hypertensive vascular restenosis.

Silencing the long noncoding RNA MALAT1 inhibits vitreous-induced epithelial-mesenchymal transition in RPE cells by regulating the PDGFRs/AKT axis

PURPOSE

Epithelial-mesenchymal transition (EMT) is a crucial pathological process that contributes to proliferative vitreoretinopathy (PVR), and research indicates that factors present in the vitreous that target cells play pivotal roles in regulating EMT. Experimental studies have confirmed that rabbit vitreous (RV) promotes EMT in human retinal pigment epithelial (RPE) cells. The long noncoding RNA (lncRNA) MALAT1 has been implicated in EMT in various diseases. Thus, this study aimed to investigate the involvement of lncRNA MALAT1 in vitreous-induced EMT in RPE cells.

METHODS

MALAT1 was knocked down in ARPE-19 cells by short hairpin RNA (shRNA) transfection. Reverse transcription PCR (RT‒PCR) was used to evaluate MALAT1 expression, and Western blotting analysis was used to measure the expression of EMT-related proteins. Wound-healing, Transwell, and cell contraction assays were conducted to assess cell migration, invasion, and contraction, respectively. Additionally, cell proliferation was assessed using the CCK-8 assay, and cytoskeletal changes were examined by immunofluorescence.

RESULTS

MALAT1 expression was significantly increased in ARPE-19 cells cultured with RV. Silencing MALAT1 effectively suppressed EMT and downregulated the associated factors snail1 and E-cadherin. Furthermore, silencing MALAT1 inhibited the RV-induced migration, invasion, proliferation, and contraction of ARPE-19 cells. Silencing MALAT1 also decreased RV-induced AKT and P53 phosphorylation.

CONCLUSIONS

In conclusion, lncRNA MALAT1 participates in regulating vitreous-induced EMT in human RPE cells; these results provide new insight into the pathogenesis of PVR and offer a potential direction for the development of antiproliferative drugs.

ASS1 metabolically contributes to the nuclear and cytosolic p53-mediated DNA damage response

Downregulation of the urea cycle enzyme argininosuccinate synthase (ASS1) in multiple tumors is associated with a poor prognosis partly because of the metabolic diversion of cytosolic aspartate for pyrimidine synthesis, supporting proliferation and mutagenesis owing to nucleotide imbalance. Here, we find that prolonged loss of ASS1 promotes DNA damage in colon cancer cells and fibroblasts from subjects with citrullinemia type I. Following acute induction of DNA damage with doxorubicin, ASS1 expression is elevated in the cytosol and the nucleus with at least a partial dependency on p53; ASS1 metabolically restrains cell cycle progression in the cytosol by restricting nucleotide synthesis. In the nucleus, ASS1 and ASL generate fumarate for the succination of SMARCC1, destabilizing the chromatin-remodeling complex SMARCC1-SNF5 to decrease gene transcription, specifically in a subset of the p53-regulated cell cycle genes. Thus, following DNA damage, ASS1 is part of the p53 network that pauses cell cycle progression, enabling genome maintenance and survival. Loss of ASS1 contributes to DNA damage and promotes cell cycle progression, likely contributing to cancer mutagenesis and, hence, adaptability potential.

Long noncoding RNA MALAT-1: A versatile regulator in cancer progression, metastasis, immunity, and therapeutic resistance

Long noncoding RNAs (lncRNAs) are RNA transcripts longer than 200 nucleotides that do not code for proteins but have been linked to cancer development and metastasis. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT-1) influences crucial cancer hallmarks through intricate molecular mechanisms, including proliferation, invasion, angiogenesis, apoptosis, and the epithelial-mesenchymal transition (EMT). The current article highlights the involvement of MALAT-1 in drug resistance, making it a potential target to overcome chemotherapy refractoriness. It discusses the impact of MALAT-1 on immunomodulatory molecules, such as major histocompatibility complex (MHC) proteins and PD-L1, leading to immune evasion and hindering anti-tumor immune responses. MALAT-1 also plays a significant role in cancer immunology by regulating diverse immune cell populations. In summary, MALAT-1 is a versatile cancer regulator, influencing tumorigenesis, chemoresistance, and immunotherapy responses. Understanding its precise molecular mechanisms is crucial for developing targeted therapies, and therapeutic strategies targeting MALAT-1 show promise for improving cancer treatment outcomes. However, further research is needed to fully uncover the role of MALAT-1 in cancer biology and translate these findings into clinical applications.

Protein Signature Differentiating Neutrophils and Myeloid-Derived Suppressor Cells Determined Using a Human Isogenic Cell Line Model and Protein Profiling

Myeloid-derived suppressor cells (MDSCs) play an essential role in suppressing the antitumor activity of T lymphocytes in solid tumors, thus representing an attractive therapeutic target to enhance the efficacy of immunotherapy. However, the differences in protein expression between MDSCs and their physiological counterparts, particularly polymorphonuclear neutrophils (PMNs), remain inadequately characterized, making the specific identification and targeting of MDSCs difficult. PMNs and PMN-MDSCs share markers such as CD11b+CD14-CD15+/CD66b+, and some MDSC-enriched markers are emerging, such as LOX-1 and CD84. More proteomics studies are needed to identify the signature and markers for MDSCs. Recently, we reported the induced differentiation of isogenic PMNs or MDSCs (referred to as iPMNs and iMDSCs, respectively) from the human promyelocytic cell line HL60. Here, we profiled the global proteomics and membrane proteomics of these cells with quantitative mass spectrometry, which identified a 41-protein signature ("cluster 6") that was upregulated in iMDSCs compared with HL60 and iPMN. We further integrated our cell line-based proteomics data with a published proteomics dataset of normal human primary monocytes and monocyte-derived MDSCs induced by cancer-associated fibroblasts. The analysis identified a 38-protein signature that exhibits an upregulated expression pattern in MDSCs compared with normal monocytes or PMNs. These signatures may provide a hypothesis-generating platform to identify protein biomarkers that phenotypically distinguish MDSCs from their healthy counterparts, as well as potential therapeutic targets that impair MDSCs without harming normal myeloid cells.

Fundamental insights and molecular interactions in pancreatic cancer: Pathways to therapeutic approaches

The gastrointestinal tract can be affected by a number of diseases that pancreatic cancer (PC) is a malignant manifestation of them. The prognosis of PC patients is unfavorable and because of their diagnosis at advanced stage, the treatment of this tumor is problematic. Owing to low survival rate, there is much interest towards understanding the molecular profile of PC in an attempt in developing more effective therapeutics. The conventional therapeutics for PC include surgery, chemotherapy and radiotherapy as well as emerging immunotherapy. However, PC is still incurable and more effort should be performed. The molecular landscape of PC is an underlying factor involved in increase in progression of tumor cells. In the presence review, the newest advances in understanding the molecular and biological events in PC are discussed. The dysregulation of molecular pathways including AMPK, MAPK, STAT3, Wnt/β-catenin and non-coding RNA transcripts has been suggested as a factor in development of tumorigenesis in PC. Moreover, cell death mechanisms such as apoptosis, autophagy, ferroptosis and necroptosis demonstrate abnormal levels. The EMT and glycolysis in PC cells enhance to ensure their metastasis and proliferation. Furthermore, such abnormal changes have been used to develop corresponding pharmacological and nanotechnological therapeutics for PC.

Has-miR-129-5p's Involvement in Different Disorders, from Digestive Cancer to Neurodegenerative Diseases

At present, it is necessary to identify specific biochemical, molecular, and genetic markers that can reliably aid in screening digestive cancer and correlate with the degree of disease development. Has-miR-129-5p is a small, non-coding molecule of RNA, circulating in plasma, gastric juice, and other biological fluids; it plays a protective role in tumoral growth, metastasis, etc. Furthermore, it is involved in various diseases, from the development of digestive cancer in cases of downregulation to neurodegenerative diseases and depression. Methods: We examined meta-analyses, research, and studies related to miR-129-5-p involved in digestive cancer and its implications in cancer processes, as well as metastasis, and described its implications in neurological diseases. Conclusions: Our review outlines that miR-129-5p is a significant controller of different pathways, genes, and proteins and influences different diseases. Some important pathways include the WNT and PI3K/AKT/mTOR pathways; their dysregulation results in digestive neoplasia and neurodegenerative diseases.

Nuclear transport maintenance of USP22-AR by Importin-7 promotes breast cancer progression

The translocation of biological macromolecules between cytoplasm and nucleus is of great significance to maintain various life processes in both normal and cancer cells. Disturbance of transport function likely leads to an unbalanced state between tumor suppressors and tumor-promoting factors. In this study, based on the unbiased analysis of protein expression differences with a mass spectrometer between human breast malignant tumors and benign hyperplastic tissues, we identified that Importin-7, a nuclear transport factor, is highly expressed in breast cancer (BC) and predicts poor outcomes. Further studies showed that Importin-7 promotes cell cycle progression and proliferation. Mechanistically, through co-immunoprecipitation, immunofluorescence, and nuclear-cytoplasmic protein separation experiments, we discovered that AR and USP22 can bind to Importin-7 as cargoes to promote BC progression. In addition, this study provides a rationale for a therapeutic strategy to restream the malignant progression of AR-positive BC by inhibiting the high expression state of Importin-7. Moreover, the knockdown of Importin-7 increased the responsiveness of BC cells to the AR signaling inhibitor, enzalutamide, suggesting that targeting Importin-7 may be a potential therapeutic strategy.

Diagnostic and Prognostic Profiling of Nucleocytoplasmic Shuttling Genes in Hepatocellular Carcinoma

One of the key features of eukaryotic cells is the separation of nuclear and cytoplasmic compartments by a double-layer nuclear envelope. This separation is crucial for timely regulation of gene expression, mRNA biogenesis, cell cycle, and differentiation. Since transcription takes place in the nucleus and the major part of translation in the cytoplasm, proper distribution of biomolecules between these two compartments is ensured by nucleocytoplasmic shuttling proteins - karyopherins. Karyopherins transport biomolecules through nuclear pores bidirectionally in collaboration with Ran GTPases and utilize GTP as the source of energy. Different karyopherins transport different cargo molecules that play important roles in the regulation of cell physiology. In cancer cells, this nucleocytoplasmic transport is significantly dysregulated to support increased demands for the import of cell cycle-promoting biomolecules and export of cell cycle inhibitors and mRNAs. Here, we analysed genomic, transcriptomic and proteomic data from published datasets to comprehensively profile karyopherin genes in hepatocellular carcinoma. We have found out that expression of multiple karyopherin genes is increased in hepatocellular carcinoma in comparison to the normal liver, with importin subunit α-1, exportin 2, importin subunit β-1 and importin 9 being the most over-expressed. More-over, we have found that increased expression of these genes is associated with higher neoplasm grade as well as significantly worse overall survival of liver cancer patients. Taken together, our bioinformatic data-mining analysis provides a comprehensive geno-mic and transcriptomic landscape of karyopherins in hepatocellular carcinoma and identifies potential members that could be targeted in order to develop new treatment regimens.

LncRNA MALAT1 regulates METTL3-mediated PD-L1 expression and immune infiltrates in pancreatic cancer

Pancreatic cancer is the fourth leading cause of cancer death in the United States. The main methods of treating pancreatic cancer are surgery and chemotherapy, but the treatment efficacy is low with a poor prognosis. Immunotherapy represented by PD-1/PD-L1 has brought a milestone progress in the treatment of pancreatic cancer. However, the unique tumor microenvironment of pancreatic cancer presents challenges for immunotherapy. In addition, m6A is a common RNA modification and a potential molecular target in tumor therapy. The expression pattern of m6A in pancreatic cancer is still unclear. LncRNAs also play an essential role in pancreatic cancer development and treatment. In this study, we found that some m6A regulators were significantly elevated in pancreatic cancer and associated with the expression of PD-1/PD-L1. Moreover, we observed that METTL3 can increase the expression of PD-L1. Notably, METTL3 positively regulates the expression of lncRNA MALAT1 in pancreatic cancer cells. Strikingly, lncRNA MALAT1 increased the expression of PD-L1 in pancreatic cancer cells. This finding indicated that METTL3 regulated the expression of PD-L1 possibly via targeting lncRNA MALAT1 in pancreatic cancer cells. Lastly, MALAT1 governed the viability of pancreatic cancer cells. Taken together, lncRNA MALAT1 is involved in METTL3-mediated promotion of PD-L1 expression in pancreatic cancer.

Resveratrol inhibits the proliferation, invasion, and migration, and induces the apoptosis of human gastric cancer cells through the MALAT1/miR-383-5p/DDIT4 signaling pathway

Background

We aimed to study the effects and potential mechanism of resveratrol (RS) in gastric cancer (GC).

Methods

The human GC cell line SGC7901 was treated with different concentrations of RS (0, 1, 5 µM) for 24 hours. The messenger ribonucleic acid or protein expressions levels of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), micro ribonucleic acid-383-5p (miR-383-5p), and DNA damage-inducible transcript 4 (DDIT4) in GC cells were determined by Western blot and quantitative real-time polymerase chain assays. Cells were then transfected with miR-383-5p inhibitor (inhibitor), inhibitor negative control (NC), MALAT1-interfering RNA (si-MALAT1), si-DDIT4 and negative interference control (si-NC). The Cell Counting Kit-8 method, scratch assay, and transwell assay were performed to evaluate cell proliferation, migration, and invasion. Additionally, flow cytometry was used to examine apoptosis, and the target relationship was examined by a luciferase-reporter gene analysis.

Results

RS treatment downregulated the expression of MALAT1, repressed cell proliferation, inhibited cell migration and invasion (all P<0.05), and induced apoptosis (P<0.05) in GC cells. When the cells were treated with RS and inhibited the expression of MALAT1 meanwhile, the above anti-cancer effects were more significant (all P<0.05). Target prediction and the luciferase-reporter gene analysis showed that MALAT1 targeted miR-383-5p (P<0.05). When suppressing the expression of MALAT1 and miR-383-5p, the anti-cancer effects caused by the silencing of MALAT1 were absent (all P<0.05). We also found that miR-383-5p targeted DDIT4 protein. When the expression of miR-383-5p and DDIT4 in the GC cells was inhibited, the promoting cancer effects caused by the inhibition of miR-383-5p were reversed (all P<0.05).

Conclusions

This study found that RS inhibited the proliferation, migration, and invasion of human GC cells through the metastasis-associated lung adenocarcinoma transcript 1 (MALAT1)/miR-383-5p/DDIT4 pathway and induced apoptosis.

Mechanisms of Immunosuppressive Tumor Evasion: Focus on Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is a malignancy with high heterogeneity in its biological features and treatments. Although the overall survival (OS) of patients with ALL has recently improved considerably, owing to the application of conventional chemo-therapeutic agents, approximately 20% of the pediatric cases and 40-50% of the adult patients relapse during and after the treatment period. The potential mechanisms that cause relapse involve clonal evolution, innate and acquired chemoresistance, and the ability of ALL cells to escape the immune-suppressive tumor response. Currently, immunotherapy in combination with conventional treatment is used to enhance the immune response against tumor cells, thereby significantly improving the OS in patients with ALL. Therefore, understanding the mechanisms of immune evasion by leukemia cells could be useful for developing novel therapeutic strategies.