PTBP1 promotes the progression of hepatocellular carcinoma by enhancing the oncogenic splicing switch of FGFR2

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer accounting for 90% of cases. It is a highly invasive and deadly cancer with a gradual onset. Polypyrimidine tract-binding protein 1 (PTBP1) is an important RNA-binding protein involved in RNA metabolism and has been linked to oncogenic splicing events. While the oncogenic role of PTBP1 in HCC cells has been established, the exact mechanism of action remains unclear. This study aimed to investigate the functional connection between PTBP1 and dysregulated splicing events in HCC. Through immunoprecipitation-mass spectrometry analyses, we discovered that the proteins bound to PTBP1 were significantly enriched in the complex responsible for the alternative splicing of FGFR2 (fibroblast growth factor receptor 2). Further RNA immunoprecipitation and quantitative PCR assays confirmed that PTBP1 down-regulated the FGFR2-IIIb isoform levels and up-regulated the FGFR2-IIIc isoform levels in HCC cells, leading to a switch from FGFR2-IIIb to FGFR2-IIIc isoforms. Subsequent functional evaluations using CCK-8, transwell, and plate clone formation assays in HCC cell lines HepG2 and Huh7 demonstrated that FGFR2-IIIb exhibited tumor-suppressive effects, while FGFR2-IIIc displayed tumor-promoting effects. In conclusion, this study provides insights into the PTBP1-mediated alternative splicing mechanism in HCC progression, offering a new theoretical basis for the prevention and treatment of this malignancy. Mechanistically, the isoform switch from FGFR2-IIIb to FGFR2-IIIc promoted epithelial-mesenchymal transformation (EMT) of HCC cells and activated the FGFR cascades ERK and AKT pathways.

HNF4A negatively regulated posterior capsular opacification via transcriptional inhibition of MMP2

Purpose: Posterior capsular opacification (PCO) is the most common complication after cataract surgery. Abnormal proliferation, migration, epithelial-mesenchymal transition (EMT), and extracellular matrix (ECM) synthesis of residual lens epithelial cells (LECs) cause matrix contraction and capsule shrinkage, which are considered to be the main pathogenic mechanisms of PCO. Hepatocyte nuclear factor 4α (HNF4A) has been reported to regulate EMT in different tumours. Our objective was to investigate the role and mechanism of HNF4A in PCO.Methods: HNF4A expression was tested in PCO rat lens capsules and cell models. HNF4A was knocked down using small hairpin RNA. Knockdown and overexpression of HNF4A were achieved by lentivirus in HLE-B3 cells. Cell viability was measured by Cell Counting Kit-8 assay. Cell migration ability was evaluated by wound healing and Transwell assays. EMT markers were detected by Western blotting. Transcriptome sequencing was used to screen for downstream effectors of HNF4A. Chromatin immunoprecipitation-qPCR and a dual luciferase reporter assay were used to determine the binding of HNF4A to the MMP2 promoter region.Results: HNF4A was downregulated in PCO tissue and cell models. In vitro studies showed that HNF4A deletion facilitated cell proliferation, migration, and EMT protein marker expression in LECs. HNF4A knockdown promoted EMT and migration of LECs via MMP2. Mechanistically, HNF4A decreased MMP2 expression by binding to the MMP2 promoter region. HNF4A deletion also promoted EMT in rat lens capsules.Conclusions: We demonstrated that HNF4A inhibited EMT of LECs by directly binding to the MMP2 promoter region and inhibiting the expression of MMP2, thus leading to retardation of PCO formation and development, suggesting that HNF4A is a potential therapeutic target for PCO.

High-grade serous ovarian tumor cells modulate NK cell function to create an immune-tolerant microenvironment

Tubo-ovarian high-grade serous carcinoma (HGSC) is unresponsive to immune checkpoint blockade despite significant frequencies of exhausted T cells. Here we apply mass cytometry and uncover decidual-like natural killer (dl-NK) cell subpopulations (CD56+CD9+CXCR3+KIR+CD3-CD16-) in newly diagnosed HGSC samples that correlate with both tumor and transitioning epithelial-mesenchymal cell abundance. We show different combinatorial expression patterns of ligands for activating and inhibitory NK receptors within three HGSC tumor compartments: epithelial (E), transitioning epithelial-mesenchymal (EV), and mesenchymal (vimentin expressing [V]), with a more inhibitory ligand phenotype in V cells. In cocultures, NK-92 natural killer cells acquire CD9 from HGSC tumor cells by trogocytosis, resulting in reduced anti-tumor cytokine production and cytotoxicity. Cytotoxicity in these cocultures is restored with a CD9-blocking antibody or CD9 CRISPR knockout, thereby identifying mechanisms of immune suppression in HGSC. CD9 is widely expressed in HGSC tumors and so represents an important new therapeutic target with immediate relevance for NK immunotherapy.

Association of Preoperative NANOG-Positive Circulating Tumor Cell Levels With Recurrence of Hepatocellular Carcinoma

Background

Cancer stem cells (CSCs) and Circulating tumor cells (CTCs) have been proposed as fundamental causes for the recurrence of hepatocellular carcinoma (HCC). CTCs isolated from patients with HCC illustrate a unique Nanog expression profile analysis. The aim of this study was to enhance the prediction of recurrence and prognosis of the CTC phenotype in patients with HCC by combining Nanog expression into a combined forecasting model.

Subjects, Materials, and Methods

We collected 320 blood samples from 160 patients with HCC cancer before surgery and used CanPatrol™ CTC enrichment technology and in situ hybridization (ISH) to enrich and detect CTCs and CSCs. Nanog expression in all CTCs was also determined. In addition, RT-PCR and immunohistochemistry were used to study the expression of Nanog, E-Cadherin, and N-Cadherin in liver cancer tissues and to conduct clinical correlation studies.

Results

The numbers of ^{EpCAM mRNA+} CTCs and ^{Nanog mRNA+} CTCs were strongly correlated with postoperative HCC recurrence (CTC number (P = 0.03), the total number of mixed CTCS (P = 0.02), and Nanog> 6.7 (P = 0.001), with Nanog > 6.7 (P = 0.0003, HR = 2.33) being the most crucial marker. There are significant differences in the expression of Nanog on different types of CTC: most Epithelial CTCs do not express Nanog, while most of Mixed CTC and Mesenchymal CTC express Nanog, and their positive rates are 38.7%, 66.7%, and 88.7%, respectively, (P=0.0001). Moreover, both CTC (≤/> 13.3) and Nanog (≤/>6.7) expression were significantly correlated with BCLC stage, vascular invasion, tumor size, and Hbv-DNA (all P < 0.05). In the young group and the old group, patients with higher Nanog expression had a higher recurrence rate. (P < 0.001).

Conclusions

The number of Nanog-positive cells showed positive correlation with the poor prognosis of HCC patients. The detection and analysis of CTC markers (EpCAM and CK8, 18, CD45 Vimentin,Twist and 19) and CSCs markers (NANOG) are of great value in the evaluation of tumor progression.

Clinical significance of Ki67 and circulating tumor cells with an epithelial-mesenchymal transition phenotype in non-small cell lung cancer

Circulating tumor cells (CTCs) are a heterogeneous population of tumor cells with distinct clinical and biological properties. The aim of the present study was to evaluate the relationship between CTCs with the epithelial-mesenchymal transition phenotype (CTC EMT) and the proliferative marker Ki67, and their prognostic value in non-small cell lung cancer (NSCLC). CTCs were isolated from the peripheral blood of 84 NSCLC patients using the CanPatrol^TM CTC enrichment method, and the expression of Ki67 in tumor tissues were detected by immunohistochemistry. Almost two-thirds (61/84) of the patients were positive for CTC EMT, and 55 (65.4%) patients had high in-situ expression of Ki67 (≥ 14%) in the tumor tissues. CTC EMT was not significantly associated with tumor size and differentiation, age, gender and histological type, but correlated with lymphatic metastasis, tumor stage and Ki67 overexpression. Furthermore, the CTC EMT+ NSCLC patients had a significantly lower recurrence-free survival (RFS) and overall survival (OS) compared to the negative patients. Similarly, Ki67 levels ≥ 14% were associated with a significantly lower RFS and OS. In conclusion, CTC EMT is significantly related to Ki67 expression, and is a risk factor of NSCLC.

Long non-coding RNA SUMO1P3 may promote cell proliferation, migration, and invasion of pancreatic cancer via EMT signaling pathway

Long non-coding RNAs (lncRNAs) have been suggested to serve important roles in the development of a number of human cancer types. An increasing amount of data has indicated that the lncRNA small ubiquitin-like modifier 1 (SUMO1) pseudogene 3 (SUMO1P3) has been involved in various types of human cancer. However, the function SUMO1P3 in the development of pancreatic cancer remains unclear. Firstly, reverse transcription-quantitative polymerase chain reaction was performed to determine the expression of SUMO1P3 in pancreatic cancer tissues and cell lines. Then, cell counting kit-8, wound-healing and transwell assays were conducted to explore the effect of SUMO1P3 on pancreatic cancer cell proliferation, migration and invasion. Finally, the EMT-associated proteins were evaluated by western blotting. The results of the present study revealed that SUMO1P3 expression was elevated in pancreatic tissues compared with the corresponding adjacent normal tissues. Additionally, the data indicated that the increased expression of SUMO1P3 is significantly associated with tumor progression and the poor survival of patients with pancreatic cancer. Furthermore, the present study identified that SUMO1P3 knockdown may suppress the proliferation, migration and invasion of pancreatic cancer cells. Additionally, downregulation of SUMO1P3 suppressed the epithelial-mesenchymal transition (EMT) and increased the expression of epithelial cadherin, and decreased the expression of neuronal cadherin, vimentin and β-catenin. Taken together, the results of the present study demonstrated that SUMO1P3 may participate in EMT and pancreatic cancer progression, thus suggesting that it may be a novel diagnostic and therapeutic biological target for pancreatic cancer.

COUP-TFII promotes colorectal carcinoma resistance to doxorubicin involving inhibition of epithelial-mesenchymal transition [corrected]

Chicken ovalbumin upstream promoter transcription factor II (COUP-TFII) promotes progression of a variety of tumors. The study was designed to explore the role of COUP-TFII in colorectal carcinoma (CRC) resistance to doxorubicin. The sensitivity of CRC cell lines to doxorubicin was calculated by different proliferation rate measured with cell count kit-8 and EdU (5-Ethynyl-2'-deoxyuridine) assay. The expression of COUP-TFII, Vimentin and E-cadherin were verified using western blot. After doxorubicin administration, CRC cell lines presented apparently down-regulated COUP-TFII, E-cadherin expression and increased Vimentin expression. Besides, COUP-TFII knock-down resulted in significantly increased sensitivity to doxorubicin in all of CRC cell lines, but Twist knock-down presented totally reversed this effect. Furthermore, COUP-TFII knock-down promoted mesenchymal-epithelial transition (MET) in CRC cell lines. After doxorubicin treatment, immediately decreased COUP-TFII expression significantly suppresses CRC cells survival outcomes by suppressing EMT [corrected].

Cancer Stem Cell Plasticity Drives Therapeutic Resistance

The connection between epithelial-mesenchymal (E-M) plasticity and cancer stem cell (CSC) properties has been paradigm-shifting, linking tumor cell invasion and metastasis with therapeutic recurrence. However, despite their importance, the molecular pathways involved in generating invasive, metastatic, and therapy-resistant CSCs remain poorly understood. The enrichment of cells with a mesenchymal/CSC phenotype following therapy has been interpreted in two different ways. The original interpretation posited that therapy kills non-CSCs while sparing pre-existing CSCs. However, evidence is emerging that suggests non-CSCs can be induced into a transient, drug-tolerant, CSC-like state by chemotherapy. The ability to transition between distinct cell states may be as critical for the survival of tumor cells following therapy as it is for metastatic progression. Therefore, inhibition of the pathways that promote E-M and CSC plasticity may suppress tumor recurrence following chemotherapy. Here, we review the emerging appreciation for how plasticity confers therapeutic resistance and tumor recurrence.