Gamma‐secretase complex‐dependent intramembrane proteolysis of CD147 regulates the Notch1 signaling pathway in hepatocellular carcinoma

BSG Isoform 2 (ENST00000353555) Is a Prognostic Biomarker in Predicting Unfavorable Overall Survival of Patients With Liver Hepatocellular Carcinoma

BACKGROUND

CD147, encoded by the BSGgene, has complex transcripts that encode proteins of different lengths. Total BSG transcription is a prognostic biomarker for patients with liver cancer. This study tried to analyze the expression profile and prognostic significance of BSG transcripts in liver cancer.

MATERIALS AND METHODS

RNA sequencing data from The Cancer Genome Atlas (TCGA) and the Genotype-Tissue Expression (GTEx) project, survival data from TCGA, and protein expression data from the Human Protein Atlas were systematically analyzed.

RESULTS

Among the four protein-coding transcripts of BSG, ENST00000353555 encoding basigin-2 is the dominant transcript isoform. It might be an independent prognostic biomarker for unfavorable overall survival in patients with liver cancer (HR: 1.404, 95% CI: 1.1224-1.754, p = 0.003).

CONCLUSIONS

ENST00000353555 might be a prognostic biomarker linking unfavorable overall survival in liver cancer patients.

BSG Isoform 2 (ENST00000353555) Is a Better Component Than Total BSG Expression in Generating Prognostic Signature for Overall Survival of Liver Cancer

BACKGROUND

The basigin (BSG) gene, also known as CD147, has been implicated in the progression and prognosis of various cancers, including liver cancer. This study aimed to comprehensively evaluate the prognostic value of total BSG expression and its specific transcript variants, ENST00000353555 and ENST00000545507, in a large cohort of patients with primary liver cancer.

MATERIALS AND METHODS

The prognostic values of total BSG, ENST00000353555, and ENST00000545507 expression in overall survival (OS) and progression-free interval (PFI) of patients with primary liver cancer were assessed using The Cancer Genome Atlas Liver Hepatocellular Carcinoma (TCGA-LIHC) dataset. Survival analysis, receiver operating characteristic (ROC) analysis, and validation of an extracellular matrix (ECM)-related prognostic signature were performed.

RESULTS

In univariate and multivariate analyses, total BSG, ENST00000353555, and ENST00000545507 expression were associated with poor OS in liver cancer patients. ENST00000353555 showed the highest hazard ratio among the three prognostic indicators. ROC analysis revealed that ENST00000353555 had better prognostic performance than total BSG expression. Replacing total BSG with ENST00000353555 in an existing ECM-related prognostic signature marginally increased the area under the curve values for one year from 0.79 to 0.80, and five-year OS from 0.72 to 0.73. ENST00000353555 showed isoform-specific positive correlations with EDNRB, IL10, C10orf54, and VEGFA.

CONCLUSIONS

ENST00000353555 serves as a better prognostic biomarker than total BSG expression in liver cancer, either as an individual marker or as a component of an ECM-related gene signature. Additionally, ENST00000353555 exhibited isoform-specific positive correlations with several immunosuppressive genes, suggesting a potential role in regulating the tumor microenvironment.

Size-exclusion chromatography combined with DIA-MS enables deep proteome profiling of extracellular vesicles from melanoma plasma and serum

Extracellular vesicles (EVs) are important players in melanoma progression, but their use as clinical biomarkers has been limited by the difficulty of profiling blood-derived EV proteins with high depth of coverage, the requirement for large input amounts, and complex protocols. Here, we provide a streamlined and reproducible experimental workflow to identify plasma- and serum- derived EV proteins of healthy donors and melanoma patients using minimal amounts of sample input. SEC-DIA-MS couples size-exclusion chromatography to EV concentration and deep-proteomic profiling using data-independent acquisition. From as little as 200 µL of plasma per patient in a cohort of three healthy donors and six melanoma patients, we identified and quantified 2896 EV-associated proteins, achieving a 3.5-fold increase in depth compared to previously published melanoma studies. To compare the EV-proteome to unenriched blood, we employed an automated workflow to deplete the 14 most abundant proteins from plasma and serum and thereby approximately doubled protein group identifications versus native blood. The EV proteome diverged from corresponding unenriched plasma and serum, and unlike the latter, separated healthy donor and melanoma patient samples. Furthermore, known melanoma markers, such as MCAM, TNC, and TGFBI, were upregulated in melanoma EVs but not in depleted melanoma plasma, highlighting the specific information contained in EVs. Overall, EVs were significantly enriched in intact membrane proteins and proteins related to SNARE protein interactions and T-cell biology. Taken together, we demonstrated the increased sensitivity of an EV-based proteomic workflow that can be easily applied to larger melanoma cohorts and other indications.

Large HBV Surface Protein-Induced Unfolded Protein Response Dynamically Regulates p27 Degradation in Hepatocellular Carcinoma Progression

Up to 50% of hepatocellular carcinoma (HCC) is caused by hepatitis B virus (HBV) infection, and the surface protein of HBV is essential for the progression of HBV-related HCC. The expression of large HBV surface antigen (LHB) is presented in HBV-associated HCC tissues and is significantly associated with the development of HCC. Gene set enrichment analysis revealed that LHB overexpression regulates the cell cycle process. Excess LHB in HCC cells induced chronic endoplasmic reticulum (ER) stress and was significantly correlated with tumor growth in vivo. Cell cycle analysis showed that cell cycle progression from G1 to S phase was greatly enhanced in vitro. We identified intensive crosstalk between ER stress and cell cycle progression in HCC. As an important regulator of the G1/S checkpoint, p27 was transcriptionally upregulated by transcription factors ATF4 and XBP1s, downstream of the unfolded protein response pathway. Moreover, LHB-induced ER stress promoted internal ribosome-entry-site-mediated selective translation of p27, and E3 ubiquitin ligase HRD1-mediated p27 ubiquitination and degradation. Ultimately, the decrease in p27 protein levels reduced G1/S arrest and promoted the progress of HCC by regulating the cell cycle.

circSLC4A7 accelerates stemness and progression of gastric cancer by interacting with HSP90 to activate NOTCH1 signaling pathway

Gastric cancer stem cells (GCSCs) play critical roles in gastric cancer (GC) initiation and development. Circular RNAs (circRNAs) participate in diverse cancer biological processes and function as tumor suppressors or oncogenes. This study aims to discover the expression profile and functional roles of circRNAs in GCSCs. A spheroid formation assay was conducted to enrich GCSCs. Genome-wide sequencing of circRNAs showed that a novel circRNA, circSLC4A7, was one of the most upregulated circRNAs in GCSCs. CircSLC4A7 was localized to the nucleus, and its level was elevated in GC cells and tissues. Furthermore, circSLC4A7 increased CSC-like properties and drove cell proliferation, migration, and invasion, which were determined by gain- and loss-of-function experiments. Specific circRNA pull-down assays followed by mass spectrometry analysis, RNA immunoprecipitation, and dual RNA-fluorescence in situ hybridization and immunofluorescence assay were conducted and HSP90 was detected to interact with circSLC4A7 and mediate the oncogenic function of circSLC4A7 by activating the Notch1 signaling pathway in GC. This study highlights a novel oncogenic function of circSLC4A7 mediated by its binding with HSP90 and thus activating the Notch1 signaling pathway.

Notch-dependent cooperativity between myeloid lineages promotes Langerhans cell histiocytosis pathology

Langerhans cell histiocytosis (LCH) is a potentially fatal neoplasm characterized by the aberrant differentiation of mononuclear phagocytes, driven by mitogen-activated protein kinase (MAPK) pathway activation. LCH cells may trigger destructive pathology yet remain in a precarious state finely balanced between apoptosis and survival, supported by a unique inflammatory milieu. The interactions that maintain this state are not well known and may offer targets for intervention. Here, we used single-cell RNA-seq and protein analysis to dissect LCH lesions, assessing LCH cell heterogeneity and comparing LCH cells with normal mononuclear phagocytes within lesions. We found LCH discriminatory signatures pointing to senescence and escape from tumor immune surveillance. We also uncovered two major lineages of LCH with DC2- and DC3/monocyte-like phenotypes and validated them in multiple pathological tissue sites by high-content imaging. Receptor-ligand analyses and lineage tracing in vitro revealed Notch-dependent cooperativity between DC2 and DC3/monocyte lineages during expression of the pathognomonic LCH program. Our results present a convergent dual origin model of LCH with MAPK pathway activation occurring before fate commitment to DC2 and DC3/monocyte lineages and Notch-dependent cooperativity between lineages driving the development of LCH cells.

Mini-Review: Can the Metastatic Cascade Be Inhibited by Targeting CD147/EMMPRIN to Prevent Tumor Recurrence?

Solid tumors metastasize very early in their development, and once the metastatic cell is lodged in a remote organ, it can proliferate to generate a metastatic lesion or remain dormant for long periods. Dormant cells represent a real risk for future tumor recurrence, but because they are typically undetectable and insensitive to current modalities of treatment, it is difficult to treat them in time. We describe the metastatic cascade, which is the process that allows tumor cells to detach from the primary tumor, migrate in the tissue, intravasate and extravasate the lymphatics or a blood vessel, adhere to a remote tissue and eventually outgrow. We focus on the critical enabling role of the interactions between tumor cells and immune cells, especially macrophages, in driving the metastatic cascade, and on those stages that can potentially be targeted. In order to prevent the metastatic cascade and tumor recurrence, we would need to target a molecule that is involved in all of the steps of the process, and evidence is brought to suggest that CD147/EMMPRIN is such a protein and that targeting it blocks metastasis and prevents tumor recurrence.

Notch signaling pathway: architecture, disease, and therapeutics

The NOTCH gene was identified approximately 110 years ago. Classical studies have revealed that NOTCH signaling is an evolutionarily conserved pathway. NOTCH receptors undergo three cleavages and translocate into the nucleus to regulate the transcription of target genes. NOTCH signaling deeply participates in the development and homeostasis of multiple tissues and organs, the aberration of which results in cancerous and noncancerous diseases. However, recent studies indicate that the outcomes of NOTCH signaling are changeable and highly dependent on context. In terms of cancers, NOTCH signaling can both promote and inhibit tumor development in various types of cancer. The overall performance of NOTCH-targeted therapies in clinical trials has failed to meet expectations. Additionally, NOTCH mutation has been proposed as a predictive biomarker for immune checkpoint blockade therapy in many cancers. Collectively, the NOTCH pathway needs to be integrally assessed with new perspectives to inspire discoveries and applications. In this review, we focus on both classical and the latest findings related to NOTCH signaling to illustrate the history, architecture, regulatory mechanisms, contributions to physiological development, related diseases, and therapeutic applications of the NOTCH pathway. The contributions of NOTCH signaling to the tumor immune microenvironment and cancer immunotherapy are also highlighted. We hope this review will help not only beginners but also experts to systematically and thoroughly understand the NOTCH signaling pathway.

CD147 supports paclitaxel resistance via interacting with RanBP1

Though the great success of paclitaxel, the variable response of patients to the drug limits its clinical utility and the precise mechanisms underlying the variable response to paclitaxel remain largely unknown. This study aims to verify the role and the underlying mechanisms of CD147 in paclitaxel resistance. Immunostaining was used to analyze human non-small-cell lung cancer (NSCLC) and ovarian cancer tissues. RNA-sequencing was used to identify downstream effectors. Annexin V-FITC/propidium iodide and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining were used to detect apoptosis. Co-immunoprecipitation (Co-IP), fluorescence resonance energy transfer (FRET) and surface plasmon resonance (SPR) were performed to determine protein interactions. Fluorescence recovery after photobleaching (FRAP) was performed to measure the speed of microtubule turnover. Xenograft tumor model was established to evaluate sensitivity of cancer cells to paclitaxel in vivo. In vitro and in vivo assays showed that silencing CD147 sensitized the cancer cells to paclitaxel treatment. CD147 protected cancer cells from paclitaxel-induced caspase-3 mediated apoptosis regardless of p53 status. Truncation analysis showed that the intracellular domain of CD147 (CD147^ICD) was indispensable for CD147-regulated sensitivity to paclitaxel. Via screening the interacting proteins of CD147^ICD, Ran binding protein 1 (RanBP1) was identified to interact with CD147^ICD via its C-terminal tail. Furthermore, we showed that RanBP1 mediated CD147-regulated microtubule stability and dynamics as well as response to paclitaxel treatment. These results demonstrated that CD147 regulated paclitaxel response by interacting with the C-terminal tail of RanBP1 and targeting CD147 may be a promising strategy for preventing paclitaxel resistant.

Cimicifuga dahurica extract inhibits the proliferation, migration and invasion of breast cancer cells MDA-MB-231 and MCF-7 in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Cimicifuga dahurica (Turcz.) Maxim (C. dahurica) has a long history of treating breast cancer. From the Qing Dynasty to the Tang Dynasty and even earlier, C. dahurica has been documented in the treatment of breast carbuncle (Breast cancer is classified as breast carbuncle in Chinese medicine). In traditional prescriptions such as "Sheng Ge Decoction", "Sheng Ma Powder" and "Breast Carbuncle Pill", as the main medicine, C. dahurica plays an important role. At present, the systematic studies on the in vitro and in vivo effects of Cimicifuga against breast cancer are rare, especially the C. dahurica.

AIM OF THE STUDY

In this article, we evaluated the in vitro activity and in vivo effects of CREE (extract of the root of C. dahurica) against breast cancer, and discussed the possible mechanism of CREE in promoting breast cancer cell apoptosis.

MATERIALS AND METHODS

The main component in the CREE was analyzed by HPLC. The effects of CREE on the proliferation, migration and invasion of human breast cancer cells were evaluated through SRB, colony assay, LDH release, wound healing and transwell assay. The pro-apoptotic effect of CREE was investigated in Hochest33342 and Annexin V-FITC/PI assay. To verify the results of CREE in vivo effects, we applied nude mice subcutaneous xenograft experiments. The possible mechanism of CREE treating breast cancer was investigated through mitochondrial membrane potential and western blot experiments.

RESULTS

CREE contains cycloartane triterpene saponins. CREE can significantly inhibit the proliferation, migration and invasion of human breast cancer MCF-7 and MDA-MB-231 cells in vitro and it can effectively inhibit the growth of MDA-MB-231 cell subcutaneous tumors in vivo. Besides, we also found that CREE up-regulated the expression levels of Bax, caspase-9/3 and cytochrome C, and down-regulated the expression of Bcl-2. Therefore, regulation of the mitochondrial pathway may be one of the mechanisms by which CREE promotes breast cancer cell apoptosis.

CONCLUSIONS

CREE exhibits sufficient anti-breast cancer activity in vivo and in vitro, this study provides persuasive evidence for the further research and development of C. dahurica.

Cimigenoside functions as a novel γ-secretase inhibitor and inhibits the proliferation or metastasis of human breast cancer cells by γ-secretase/Notch axis

Breast cancer (BC) occurrence and development tremendously affect female health. Currently breast cancer targeted drugs are still scarce. Natural products have become the main source of targeted drug for breast cancer due to low toxicity and high efficiency. Cimigenoside, natural compound isolated and purified from Cimicifuga dahurica (Turcz.) Maxim has been suggested to utilize for breast cancer treatment, however the mechanism of action has not been elucidated yet. In this article, the antitumor potential of Cimigenoside against breast cancer in vitro and in vivo study. Moreover, we further predicted the possible binding mode of Cimigenoside with γ-secretase through molecular docking studies. The results show that Cimigenoside has a significant inhibitory effect towards the proliferation or metastasis of breast cancer cells via suppressing the Notch signaling pathway-mediated mitochondrial apoptosis and EMT (epithelial mesenchymal transition). In terms of mechanism, Cimigenoside could inhibit the activation of PSEN-1, the catalytic subunit of γ-secretase, and also by cleaving the Notch protein mediated by PSEN-1. Overall, our findings provide scientific support to utilize Cimigenoside as an effective targeted drug for clinical treatment of BC.

Notch Signaling Regulation in HCC: From Hepatitis Virus to Non-Coding RNAs

The Notch family includes evolutionary conserved genes that encode for single-pass transmembrane receptors involved in stem cell maintenance, development and cell fate determination of many cell lineages. Upon activation by different ligands, and depending on the cell type, Notch signaling plays pleomorphic roles in hepatocellular carcinoma (HCC) affecting neoplastic growth, invasion capability and stem like properties. A specific knowledge of the deregulated expression of each Notch receptor and ligand, coupled with resultant phenotypic changes, is still lacking in HCC. Therefore, while interfering with Notch signaling might represent a promising therapeutic approach, the complexity of Notch/ligands interactions and the variable consequences of their modulations raises concerns when performed in undefined molecular background. The gamma-secretase inhibitors (GSIs), representing the most utilized approach for Notch inhibition in clinical trials, are characterized by important adverse effects due to the non-specific nature of GSIs themselves and to the lack of molecular criteria guiding patient selection. In this review, we briefly summarize the mechanisms involved in Notch pathway activation in HCC supporting the development of alternatives to the γ-secretase pan-inhibitor for HCC therapy.

Identification of immune-related lncRNA signature for predicting immune checkpoint blockade and prognosis in hepatocellular carcinoma

BACKGROUND

An increasing body of evidence has supported that long non-coding RNAs (lncRNAs) can play as essential roles of various physiological process and pathological diseases. We aimed to construct a robust immune-associated lncRNA signature associated with the prognosis for HCC survival prediction.

METHODS

7 immune-associated lncRNAs presenting significant correlation with survival were screened through stepwise univariate Cox regression and LASSO algorithm, and multivariate Cox regression. Kaplan-Meier analysis, proportional hazards model, and ROC analyses further conducted. Gene set enrichment analysis (GSEA) was applied for functional annotation. We conducted quantitative real-time polymerase chain reaction to determine NRAV expression and preliminarily explored the latent role of NRAV in prognosis of HCC patients.

RESULTS

Finally, 7 immune-related lncRNA signature composed of AC007405.3, AC023157.3, NRAV, CASC19, MSC-AS1, GASAL1, and LINC00942 were validated. This lncRNAs signature can serve as an independent predictive biomolecular factor. This signature was further confirmed in the validation group and the entire cohort. We demonstrated that NRAV was significantly upregulated in HCC cell lines and it may serve as a key regulator in HCC. Our signature was associated to apoptosis and immunologic characteristics. This signature mediated immune cell infiltration (i.e., Dendritic, etc.,) and immune checkpoint blockade (ICB) immunotherapy-related molecules (i.e., CD274, etc.,).

CONCLUSION

This immune-related lncRNA signature possesses promising prognostic value in HCC and may have the potentiality to predict clinical outcome of ICB immunotherapy.

γ-Secretase inhibitors for breast cancer and hepatocellular carcinoma: From mechanism to treatment

The γ-secretase complex is a key hydrolase for many type 1 transmembrane proteins. It is very important for activation of the Notch receptor and regulation of target-gene transcription. Abnormal activation and expression of the Notch pathway are closely related to the occurrence and development of many tumor types, including breast cancer and liver cancer. In this review, we elaborated on the basic situation of γ-secretase complex and the biological function and role of γ-secretase in APP and Notch signal pathway are described in detail. Subsequently, all currently known γ-secretase inhibitors and γ-secretase modulators are listed and their mechanism of action, value of IC₅₀, chemical structure and current research stage are summarized. Next, the selection presented the treatment progress of γ-secretase inhibitors in breast cancer and hepatocellular carcinoma in the past five years. Finally, the mechanism of action of γ-secretase-mediated breast cancer and hepatocellular carcinoma and the advantages and disadvantages of γ-secretase inhibitors are discussed, and the concept of further research is proposed.

Di-methylation of CD147-K234 Promotes the Progression of NSCLC by Enhancing Lactate Export

CD147 is a tumor-associated glycoprotein that regulates cell metabolism. However, CD147 methylation and its subsequent role in cancer cell metabolism remain unclear. Here, we detect CD147 di-methylation in 16 non-small-cell lung cancer (NSCLC) tissues using liquid chromatography-tandem mass spectrometry. CD147 is di-methylated to CD147-K234me2 by lysine methyltransferase 5A (KMT5A). The increase in KMT5A expression boosts the levels of CD147-K234me2, further promoting the interaction between CD147 and monocarboxylate transporter 4 (MCT4), which enhances the translocation of MCT4 from the cytoplasm to the membrane. Overexpression of CD147-K234me2 and KMT5A enhances glycolysis and lactate export in NSCLC cells. Clinical analysis shows that high CD147-K234me2 expression is significantly related to cancer progression and overall survival, and has prognostic significance in individuals with NSCLC, especially for those in the early stages. Our findings indicate that CD147-K234me2 plays a critical role in cancer metabolism, and it can be a highly promising therapeutic target for NSCLC.

Metformin inhibits proliferation of oral squamous cell carcinoma cells by suppressing proteolysis of nerve growth factor receptor

OBJECTIVE

We aimed to explore the effects of metformin on oral squamous cell carcinoma (OSCC) cell proliferation and the associated molecular mechanisms.

METHODS

We established an OSCC model in SCC15 cells overexpressing nerve growth factor receptor (NGFR) or the N-terminal region (aa 1-250; NGFR-N), and assessed cell proliferation by CCK-8 assay, colony formation assay, and cell cycle analysis. Levels of NGFR and related genes and proteins were detected by qPCR and western blotting, and NGFR and NGFR-N affinity for p53 was assessed by immunoprecipitation assay. Additionally, the effects of NGFR and NGFR-N on p53 binding with its downstream gene promoters were analyzed by chromatin immunoprecipitation.

RESULTS

Metformin inhibited OSCC cell proliferation and blocked NGFR proteolysis, thereby reducing the generation of its intracellular domain and NGFR-N. Moreover, compared with NGFR, NGFR-N showed higher affinity for p53 and more strongly inactivated p53 to promote cell proliferation. Furthermore, upregulation of NGFR-N downregulated levels of p53-specific downstream transcripts and proteins, whereas these levels were significantly upregulated in metformin-treated cells overexpressing NGFR.

CONCLUSIONS

These results showed that metformin inhibited cell proliferation by suppressing NGFR proteolysis, thereby promoting its antitumor effect in OSCC and offering novel insight into a role for metformin in OSCC treatment.

The substrate repertoire of γ-secretase/presenilin

The intramembrane protease γ-secretase is a hetero-tetrameric protein complex with presenilin as the catalytic subunit and cleaves its membrane protein substrates within their single transmembrane domains. γ-Secretase is well known for its role in Notch signalling and in Alzheimer's disease, where it catalyzes the formation of the pathogenic amyloid β (Aβ) peptide. However, in the 21 years since its discovery many more substrates and substrate candidates of γ-secretase were identified. Although the physiological relevance of the cleavage of many substrates remains to be studied in more detail, the substrates demonstrate a broad role for γ-secretase in embryonic development, adult tissue homeostasis, signal transduction and protein degradation. Consequently, chronic γ-secretase inhibition may cause significant side effects due to inhibition of cleavage of multiple substrates. This review provides a list of 149 γ-secretase substrates identified to date and highlights by which expeirmental approach substrate cleavage was validated. Additionally, the review lists the cleavage sites where they are known and discusses the functional implications of γ-secretase cleavage with a focus on substrates identified in the recent past, such as CHL1, TREM2 and TNFR1. A comparative analysis demonstrates that γ-secretase substrates mostly have a long extracellular domain and require ectodomain shedding before γ-secretase cleavage, but that γ-secretase is also able to cleave naturally short substrates, such as the B cell maturation antigen. Taken together, the list of substrates provides a resource that may help in the future development of drugs inhibiting or modulating γ-secretase activity in a substrate-specific manner.

Identification and Validation of a Prognostic lncRNA Signature for Hepatocellular Carcinoma

Background: An accumulating body of evidence suggests that long non-coding RNAs (lncRNAs) can serve as potential cancer prognostic factors. However, the utility of lncRNA combinations in estimating overall survival (OS) for hepatocellular carcinoma (HCC) remains to be elucidated. This study aimed to construct a powerful lncRNA signature related to the OS for HCC to enhance prognostic accuracy. Methods: The expression patterns of lncRNAs and related clinical data of 371 HCC patients were obtained based on The Cancer Genome Atlas (TCGA). Differentially expressed lncRNAs (DElncRNAs) were acquired by comparing tumors with adjacent normal samples. lncRNAs displaying significant association with OS were screened through univariate Cox regression analysis and the least absolute shrinkage and selection operator (LASSO) algorithm. All cases were classified into the validation or training group at the ratio of 3:7 to validate the constructed lncRNA signature. Data from the Gene Expression Omnibus (GEO) were used for external validation. We conducted real-time polymerase chain reaction (PCR) and assays for Transwell invasion, migration, CCK-8, and colony formation to determine the biological roles of lncRNA. Gene set enrichment analysis (GSEA) of the lncRNA model risk score was also conducted. Results: We identified 1292 DElncRNAs, among which 172 were significant in univariate Cox regression analysis. In the training group (n = 263), LASSO regression analysis confirmed 11 DElncRNAs including AC010547.1, AC010280.2, AC015712.7, GACAT3 (gastric cancer associated transcript 3), AC079466.1, AC089983.1, AC051618.1, AL121721.1, LINC01747, LINC01517, and AC008750.3. The prognostic risk score was calculated, and the constructed risk model showed significant correlation with HCC OS (log-rank P-value of 8.489e-9, hazard ratio of 3.648, 95% confidence interval: 2.238-5.945). The area under the curve (AUC) for this lncRNA model was up to 0.846. This risk model was confirmed in the validation group (n = 108), the entire cohort, and the external GEO dataset (n = 203). GACAT3 was highly expressed in HCC tissues and cell lines. Based on online databases, GACAT3 expression independently affects both OS and disease-free survival in HCC patients. Silencing GACAT3 in vitro significantly suppressed HCC cell proliferation, invasion, and migration. Moreover, pathways related to the lncRNA model risk score were confirmed by GSEA. Conclusion: The lncRNA signature established in this study can be used to predict HCC prognosis, which could provide novel clinical evidence to guide targeted HCC treatment.

Detachment Activated CyPA/CD147 Induces Cancer Stem Cell Potential in Non-stem Breast Cancer Cells

BACKGROUND

Cancer stem cells (CSCs), responsible for cancer metastasis and recurrence, are generated from non-CSCs after chemo-radiation therapy. This study investigated the induction of CSC potential in non-stem breast cancer cells and the underlying molecular mechanisms in detachment culture.

METHODS

Bulk breast cancer cells, or sorted non-CSCs and CSCs were cultured under an attached or detached condition to assess CSC numbers, ability to form tumor spheres, expression of stemness markers, and chemoresistance. Lentivirus carrying CD147 shRNA or cDNA was used to manipulate CD147 expression, while CD147 ligand recombinant cyclophilin A (CyPA) or its inhibitor was used to activate or inhibit CD147 signaling.

RESULTS

Detachment promoted anoikis resistance, chemoresistance, sphere formation, self-renewal, and expression of stemness markers in breast cancer cells. Detachment increased functional ALDH⁺ or CD44^highCD24^-/low CSCs, and induced CSC potential in ALDH^- or CD44 ^low CD24^high non-CSCs. Upon detachment, both CD147 expression and CyPA secretion were enhanced, and CyPA-CD147 activation mediated detachment induced CSC potential in non-CSCs via STAT3 signaling. Clinically, CD147 and pSTAT3 were highly co-expressed and correlated with poor overall survival and tumor recurrence in breast cancer patients.

CONCLUSION

This study demonstrates that detachment induces the generation of CSCs from non-stem breast cancer cells via CyPA-CD147 signaling, indicating that targeting CD147 may serve as a potential novel therapeutic strategy for lethal metastatic breast cancer by eliminating induced CSCs.