Colony Formation Research Articles

MCM4 Promotes the Progression of Malignant Melanoma by Activating the PI3K/AKT Pathway.

This study aims to elucidate the role of minichromosome maintenance protein 4 (MCM4) in malignant melanoma (MM) and explore the underlying mechanism. Initially, data from The Cancer Genome Atlas (TCGA) database and the Molecular Signature Database (MSigDB) were used to investigate the biological impact of MCM4 on MM. Further, a prognostic model using Cox regression analysis was developed to predict the overall survival (OS) rate in the MM patients. The effects of MCM4 on the proliferation, migration, and invasion abilities of MM (B16F0 and A375) cells were demonstrated using the CCK-8, colony formation, EDU, wound scratch, and Transwell assays. In subcutaneous tumor models in C57BL/6 mice invivo, the expression levels of MCM4 in MM cells and tumors were detected using Western blot and immunofluorescence approaches. The bioinformatics analysis indicated that MCM4 was expressed higher in MM tissues than in the normal tissues (p < 0.05). The established OS prediction model could significantly contribute to devising follow-up strategies and treating MM patients. MCM4 knockdown resulted in reduced proliferation, migration, and invasion abilities of MM cells, which were reversed by MCM4 overexpression (p < 0.05). Moreover, MCM4 could activate the phosphatidylinositol 3'-kinase (PI3K)/AKT pathway in MM cells. The PI3K inhibitor (LY294002) could reverse the effects of MCM4 on MM cells. MCM4 could substantially prompt the tumor growth of MM in mice through the PI3K/AKT pathway invivo. In summary, MCM4 prompted the development and metastasis of MM by activating the PI3K/AKT pathway.

NEK2 Promotes ESCC Malignant Progression by Inhibiting Cellular Senescence via the FOXM1/c-Myc/p27 Signaling Pathway.

Never in mitosis gene A (NIMA)-related kinase 2 (NEK2) is a crucial serine-threonine kinase involved in the process of cell mitosis. However, the precise relationship between NEK2 and esophageal squamous cell carcinoma (ESCC) remains inadequately understood. NEK2 expression in ESCC tissues was assessed through bioinformatics analysis, reverse transcription-quantitative PCR (RT-qPCR) and immunohistochemistry, revealing a correlation with ESCC patient prognosis. Cultured ESCC cells and human normal esophageal epithelial cells (HEEC) were used to investigate the effects of NEK2 knockdown on the development and progression of ESCC by integrated confluence algorithm, colony formation, wound-healing, transwell, and ESCC xenograft tumor model, in vitro and in vivo. In ESCC tissues, NEK2 was found to be significantly upregulated, and its expression correlated with poor prognosis in ESCC patients. NEK2 may facilitate ESCC development by regulating cell proliferation, migration, and invasion. Additionally, results from in vivo experiments suggested that NEK2 knockdown can inhibit tumor growth. Moreover, forkhead box M1 (FOXM1) was identified as a potential downstream target of NEK2 in the regulation of ESCC, with its overexpression reversing the effects of NEK2 knockdown on ESCC. Mechanistic studies also indicated that NEK2 may promote the malignant progression of ESCC by inhibiting cellular senescence through the activation of the FOXM1/c-Myc/p27 signaling pathways, which may provide a novel perspective for the management of ESCC.

HPRT1: a preliminary investigation on its involvement in nasopharyngeal carcinoma.

Accumulating evidences have stressed the association between hypoxanthine phosphoribosyl transferase 1 (HPRT1) overexpression and the poor prognosis of various cancers. Our study, herein, preliminarily investigates the involvement of HPRT1 in nasopharyngeal carcinoma (NPC). Data from TCGA were applied to read HPRT1 expression in diverse cancers including NPC and to predict the prognosis of NPC patients. The total RNA and protein from NPC cells and nasopharyngeal epithelial cells NP460 were extracted to quantify HPRT1 expression. Following the completion of transfection, the proliferation and migration of NPC cells were determined employing MTT, colony formation and western blot assay (the quantification on expressions of protein related to proliferation and migration). HPRT1 was differentially expressed in diverse cancers yet particularly highly expressed in NPC, and high HPRT1 expression was related to the poor prognosis of NPC patients. Also, HPRT1 expression was higher in NPC cells and its silencing diminished the viability and proliferation of NPC cells and reduced the expressions of CyclinD1, CyclinE, Multidrug Resistance Protein 1 (MDR1), matrix metalloproteinase (MMP)-2, and MMP-9. This study preliminarily explored the involvement of HPRT1 in NPC based on some cellular assays in vitro, which may provide evidence for investigating the specific mechanism underlying the effects of HPRT1 in cancers.

RNF19A inhibits bladder cancer progression by regulating ILK ubiquitination and inactivating the AKT/mTOR signalling pathway.

The role of the RING finger protein superfamily in carcinogenesis has been widely studied, but one member of this family, RNF19A, has not yet been thoroughly explored in bladder cancer (BCa). The expression levels of RNF19A in BCa samples and cell lines were analysed through data mining of public resources and further experiments. BCa cells in which RNF19A was stably overexpressed or knocked down were generated through lentivirus infection. The effects of RNF19A on cell proliferation, migration, and invasion were explored by performing a series of in vitro experiments, including CCK-8, colony formation, wound healing, and Transwell invasion assays. Using bioinformatics methods and multiple experiments, including western blot, qRT‒PCR, immunoprecipitation, cycloheximide, ubiquitination, and rescue assays, the mechanism underlying the effect of RNF19A on the progression of BCa was investigated. Here, we found that RNF19A expression was reduced in BCa samples and cell lines and that lower RNF19A expression predicted shorter overall survival of BCa patients. Functionally, forced expression of RNF19A suppressed BCa cell proliferation, migration, and invasion by inactivating the AKT/mTOR signalling pathway, whereas silencing RNF19A had the opposite effects. Mechanistically, RNF19A could directly interact with ILK and promote its ubiquitination and degradation. Rescue experiments revealed that forced ILK expression partially rescued the decreased phosphorylation of AKT, mTOR, and S6K1 caused by RNF19A overexpression and that the increased levels of the p-AKT, p-mTOR, and p-S6K1 proteins induced by RNF19A knockdown were eliminated after silencing ILK. Similarly, the effects of RNF19A overexpression or knockdown on the phenotypes of cell proliferation, migration, and invasion could also be restored by forced or decreased ILK expression. RNF19A suppressed the proliferation, migration, and invasion abilities of BCa cells by regulating ILK ubiquitination and inactivating the AKT/mTOR signalling pathway. RNF19A might be a potential prognostic biomarker and promising therapeutic target for BCa.

The radiosensitivity of niraparib tosylate to esophageal squamous cell carcinoma is stronger under hypoxia and higher-pressure conditions

Background: Radiotherapy is an effective method for esophageal squamous cell carcinoma (ESCC) treatment show reduced effectiveness in long-term due to reduced sensitivity of cancer cells to radiotherapy. Niraparib tosylate, a poly ADP-ribose polymerase (PARP) inhibitor may enhance the radiosensitivity of these cells. Hence, the present study was aimed to study the effects of niraparib tosylate on ESCC proliferation, apoptosis and cell cycle along with radiosensitivity enhancement efficiency. Materials and methods: ESCC cell lines, KYSE-30 were subjected to niraparib tosylate or irradiation treatments or combination of both. CCK8 and colony formation assays were performed to monitor cell growth status. Cell cycle and apoptosis level were investigated through flow cytometry. The expressions of targeted genes were detected at protein levels by western blot. Besides, xenografts were successfully established in immunocompromised mice. Student’s t-test was used to compare data and P &lt; 0.05 was considered statistically significant. Results: Treatment with niraparib tosylate showed G2/M cycle arrest and apoptosis in KYSE-30 cells and the rate was observed to be more significant with combination therapy. These effects were further strengthened when cells were cultured under hypoxia and high atmospheric pressure. An enhanced susceptibility to radiotherapy was observed with niraparib tosylate combination. The homologous recombination related regulator, Rad51, showed remarkable upregulation in cancer cells exposed to combination of drug-radiation treatment. The tumor burden was also relieved in xenograft mouse models with combination of drug-radiation treatment, indicating the potential of niraparib tosylate use clinical cancer therapy. Conclusion: From the results, a novel function of niraparib tosylate can be established, impairing DNA damage repair efficiency to increase the susceptibility of ESCC to radiotherapy, resulting in cell apoptosis and G2/M cycle arrest in vitro and in vivo.

Mesenchymal stem cell-derived exosomes carrying miR-486-5p inhibit glycolysis and cell stemness in colorectal cancer by targeting NEK2.

Colorectal cancer (CRC) is a major global concern. Mesenchymal stem cell-derived exosomes (MSC-EXOs) have demonstrated efficacy as a therapeutic approach for colorectal cancer. However, the precise mechanism by which MSC-EXOs treat colorectal cancer remains unclear. Human umbilical cord (hUC)-MSC-EXOs were isolated and identified. Cell Counting Kit-8 (CCK-8), Transwell, and colony formation assays were used to assess the activity of CRC cells. Glucose consumption, lactic acid production, and extracellular acidification rate (ECAR) were measured to assess glycolytic activity. Cell stemness was assessed using a sphere-formation assay. Furthermore, MSC-exosomal microRNAs (miRNAs) in CRC tissues were analyzed using the EVmiRNA database, and aberrantly expressed miRNAs in CRC cells were obtained from the Gene Expression Omnibus (GEO) database. The binding relationship between miR-486-5p and the never in mitosis gene A-related kinase 2 (NEK2) was predicted using the Starbase database and validated through RNA binding protein immunoprecipitation (RIP) and dual luciferase assays. These results showed that hUC-MSC-EXOs inhibited the proliferation and metastasis of CRC cells. Moreover, glycolysis and stemness abilities of CRC cells also decreased after treatment with hUC-MSC-EXOs. miR-486-5p was found to be enriched in hUC-MSC-EXOs and significantly downregulated in CRC cells. miR-486-5p directly bound to NEK2. Overexpression of NEK2 reversed the inhibitory effect of miR-486-5p on CRC cell glycolysis and stemness. Our study highlights that hUC-MSC-EXO miR-486-5p inhibits glycolysis and cell stemness in CRC by targeting NEK2. This finding offers compelling evidence supporting the potential application of hUC-MSC-EXOs in the treatment of CRC.

LINC02466 promotes the progression of hepatocellular carcinoma through the mTOR pathway.

Long non-coding RNAs (lncRNAs) LINC02466 is an lncRNA newly linked to the adverse outcomes in primary liver cancer patients, and its crucial involvement in the disease's escalation. Decoding the specific role of LINC02466 in HCC progression is of great significance to provide a potential therapeutic target for HCC. RT-qPCR and Western Blot techniques was used to analyze the expression levels of LINC02466 in both malignant and surrounding healthy liver tissues. CCK8 assays and colony formation experiments indicates the LINC02466's effect on the proliferation rates of liver cancer cells. Flow cytometry was pivotal in revealing its significant influence on the cell cycle of these cells. Kaplan-Meier survival analysis with log-rank tests were employed. The suppression of LINC02466 markedly reduces the stemness attributes of liver cancer cells, indicating a potential therapeutic target. LINC02466 overexpression significantly increased tumor growth rates and final volumes. Further research indicated that LINC02466 significantly influences liver cancer progression through regulating the mTOR signaling pathway. LINC02466 regulating cell proliferation, the cell cycle, and stemness characteristics via the mTOR pathway, suggesting LINC02466 as a potential therapeutic target for primary liver cancer.

Extracellular vesicle-packaged miR-4253 secreted by cancer-associated fibroblasts facilitates cell proliferation in gastric cancer by inducing macrophage M2 polarization

ABSTRACT Cancer-associated fibroblasts (CAFs) can interact with macrophages in the tumor microenvironment by secreting extracellular vesicles (EVs), thereby affecting tumor progression. However, the mechanisms of CAF-secreted EVs in gastric cancer (GC) remain not well understood. Here, we investigated the effect of CAF-EVs on macrophage polarization in GC and the underlying mechanisms. Macrophage polarization was evaluated using flow cytometry and quantitative real-time polymerase chain reaction. GC cell proliferation was determined using cell counting kit-8, EdU, and colony formation assays. The molecular mechanism was explored using microarray analysis, dual-luciferase reporter assay, and RNA pull-down analysis. The results showed that CAFs secreted EVs that inhibit macrophage M1 polarization and promote M2 polarization. Moreover, miR-4253 expression was increased in CAF-EVs, and inhibition of miR-4253 reversed the macrophage polarization induced by EVs. IL6R was identified as the target of miR-4253. Additionally, macrophages treated with EVs that encapsulated miR-4253 promote GC cell proliferation. In conclusion, CAF-secreted EVs packaging miR-4253 facilitate macrophage polarization from M1 to M2 phenotype by targeting IL6R, thereby accelerating GC cell proliferation. The findings suggest that EV-encapsulated miR-4253 may be a promising therapeutic target of GC.

Capivasertib augments chemotherapy via Akt inhibition in preclinical small cell lung cancer models.

Small cell lung cancer (SCLC) is a highly aggressive type of lung cancer for which platinum-based chemotherapy is the standard of care. Despite an initial response to this therapy, patients eventually develop resistance to the chemotherapy. To investigate the potential of capivasertib, an approved drug for advanced breast cancer, to enhance the efficacy of cisplatin in preclinical SCLC models and explore the underlying mechanisms. SCLC cell lines were treated with capivasertib and cisplatin, alone or in combination, to assess cell viability, proliferation, colony formation, and apoptosis. Next, capivasertib's effects, alone and combined with cisplatin, were evaluated in an SCLC mouse model. Mechanistic studies focused on Akt and MYC signaling, with constitutively active Akt overexpression used to assess its role. Capivasertib is active against a panel of SCLC cell lines regardless of cellular origin and genetic profiling with IC50 at a clinically achievable range. Particularly, capivasertib inhibits proliferation and anchorage-independent colony formation and induces apoptosis in SCLC cells. It significantly augments cisplatin's inhibitory effects in all tested cell lines. Importantly, capivasertib at a non-toxic dose is effective in delaying SCLC growth in mice and its combination with cisplatin achieves nearly complete tumor growth inhibition. Mechanistic studies confirm that capivasertib inhibits Akt and MYC signaling, and furthermore, that overexpression of constitutively active Akt reversed anti-SCLC activity of capivasertib. Our work is the first to reveal that Akt inhibition can augment chemotherapy in SCLC, and capivasertib is a useful addition to the treatment armamentarium for SCLC.

A nanoencapsulated oral formulation of fenretinide promotes local and metastatic breast cancer dormancy in HER2/neu transgenic mice

BackgroundPrevention and treatment of metastatic breast cancer (BC) is an unmet clinical need. The retinoic acid derivative fenretinide (FeR) was previously evaluated in Phase I-III clinical trials but, despite its excellent tolerability and antitumor activity in preclinical models, showed limited therapeutic efficacy due to poor bioavailability. We recently generated a new micellar formulation of FeR, Bionanofenretinide (Bio-nFeR) showing enhanced bioavailability, low toxicity, and strong antitumor efficacy on human lung cancer, colorectal cancer, and melanoma xenografts. In the present study, we tested the effect of Bio-nFeR on a preclinical model of metastatic BC.MethodsWe used BC cell lines for in vitro analyses of cell viability, cell cycle and migratory capacity. For in vivo studies, we used HER2/neu transgenic mice (neuT) as a model of spontaneously metastatic BC. Mice were treated orally with Bio-nFeR and at sacrifice primary and metastatic breast tumors were analyzed by histology and immunohistochemistry. Molecular pathways activated in primary tumors were analyzed by immunoblotting. Stem cell content was assessed by flow cytometry, immunoblotting and functional assays such as colony formation ex vivo and second transplantation assay in immunocompromised mice.ResultsBio-nFeR inhibited the proliferation and migration of neuT BC cells in vitro and showed significant efficacy against BC onset in neuT mice. Importantly, Bio-nFeR showed the highest effectiveness against metastatic progression, counteracting both metastasis initiation and expansion. The main mechanism of Bio-nFeR action consists of promoting tumor dormancy through a combined induction of antiproliferative signals and inhibition of the mTOR pathway.ConclusionThe high effectiveness of Bio-nFeR in the neuT model of mammary carcinogenesis, coupled with its low toxicity, indicates this formulation as a potential candidate for the treatment of metastatic BC and for the adjuvant therapy of BC patients at high risk of developing metastasis.

Knockdown of Inhibin Beta A Reversed the Epithelial Growth Factor Receptor Tyrosine Kinase Inhibitor Resistance and Enhanced the Therapeutic Effect of Radiotherapy in Non-Small Cell Lung Cancer.

Lung cancer is a malignant tumor with the highest mortality rate worldwide. Non-small cell lung cancer (NSCLC) accounts for approximately half of all lung cancer cases. Inhibin beta A (INHBA) is a ligand of the transforming growth factor-beta superfamily. This study aimed to analyze the function of INHBA in NSCLC resistance cells. Gene Expression Omnibus and The Cancer Genome Atlas databases were used to identify differentially expressed genes (DEGs) in NSCLC resistance cells and patients. DEGs were further analyzed by gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis. A colony formation assay was performed to determine cell growth. Cell migration and invasion were tested by Transwell assay. Epithelial-mesenchymal transition (EMT)-related genes were analyzed using qRT-PCR and Western blot analysis. Using bioinformatics tools, INHBA was demonstrated to be overexpressed in NSCLC resistant cells and patients. Gefitinib treatment affected NSCLC resistant cells. Additionally, INHBA silencing or X-ray treatment suppressed the growth and metastasis of NSCLC resistant cells. Moreover, the combined application of INHBA silencing and X-ray treatment enhances the therapeutic effects. Moreover, EMT has been confirmed to occur in NSCLC resistant cell lines. Both INHBA silencing and X-ray treatment inhibited EMT development. This study demonstrated that INHBA silencing ameliorates EGFR-TKI resistance and enhances the therapeutic effect of radiotherapy in NSCLC.

Tanshinone II A Facilitates Chemosensitivity of Osteosarcoma Cells to Cisplatin via Activation of p38 MAPK Pathway.

To examine the mechanism of action of tanshinone II A (Tan II A) in promoting chemosensitization of osteosarcoma cells to cisplatin (DDP). The effects of different concentrations of Tan II A (0-80 µ mol/L) and DDP (0-2 µ mol/L) on the proliferation of osteosarcoma cell lines (U2R, U2OS, 143B, and HOS) at different times were examined using the cell counting kit-8 and colony formation assays. Migration and invasion of U2R and U2OS cells were detected after 24 h treatment with 30 µ mol/L Tan II A, 0.5 µ mol/L DDP alone, and a combination of 10 µ mol/L Tan II A and 0.25 µ mol/L DDP using the transwell assay. After 48 h of treatment of U2R and U2OS cells with predetermined concentrations of each group of drugs, the cell cycle was analyzed using a cell cycle detection kit and flow cytometry. After 48 h treatment, apoptosis of U2R and U2OS cells was detected using annexin V-FITC apoptosis detection kit and flow cytometry. U2R cells were inoculated into the unilateral axilla of nude mice and then the mice were randomly divided into 4 groups of 6 nude mice each. The 4 groups were treated with equal volume of Tan II A (15 mg/kg), DDP (3 mg/kg), Tan II A (7.5 mg/kg) + DDP (1.5 mg/kg), and normal saline, respectively. The body weight of the nude mice was weighed, and the tumor volume and weight were measured. Cell-related gene and signaling pathway expression were detected by RNA sequencing and Kyoto Encyclopedia of Genes and Genomes pathway analysis. p38 MAPK signaling pathway proteins and apoptotic protein expressions were detected by Western blot. In vitro studies have shown that Tan II A, DDP and the combination of Tan II A and DDP inhibit the proliferation, migration and invasion of osteosarcoma cells. The inhibitory effect was more pronounced in the Tan II A and DDP combined treatment group (P<0.05 or P<0.01). Osteosarcoma cells underwent significantly cell-cycle arrest and cell apoptosis by Tan II A-DDP combination treatment (P<0.05 or P<0.01). In vivo studies demonstrated that the Tan II A-DD combination treatment group significantly inhibited tumor growth compared to the Tan II A and DDP single drug group (P<0.01). Additionally, we found that the combination of Tan II A and DDP treatment enhanced the p38 MAPK signaling pathway. Western blot assays showed higher p-p38, cleaved caspase-3, and Bax and lower caspase-3, and Bcl-2 expressions with the combination of Tan II A and DDP treatment compared to the single drug treatment (P<0.01). Tan II A synergizes with DDP by activating the p38/MAPK pathway to upregulate cleaved caspase-3 and Bax pro-apoptotic gene expressions, and downregulate caspase-3 and Bcl-2 inhibitory apoptotic gene expressions, thereby enhancing the chemosensitivity of osteosarcoma cells to DDP.

Iran as Subaltern Empire: Lake Orumiyeh, Environmental Injustice, and Coloniality in Iranian Azerbaijan

AbstractIn recent years, protests have emerged to save Lake Orumiyeh, which has nearly vanished following decades of agricultural development, dam building, and drought. Lake Orumiyeh is located in Iranian Azerbaijan, which sits at the intersection of three former empires: Persian, Ottoman, and Russian. Iranian Azerbaijan is largely comprised of ethno‐linguistic minority communities that are unevenly impacted by environmental hazards stemming from the lake's desiccation, and protests to save the lake are generally characterised as environmental conflict resulting from climate change or as a reflection of ethno‐nationalist tensions in Iran. These readings, however, fail to account for how imperial pasts and colonial presents shape exposure to environmental violence. This article posits that environmental violence functions as a form of coloniality and, using Lake Orumiyeh as an entry point, aims to: (i) examine coloniality in a country that was never formally colonised yet impacted by different formations of empire; (ii) account for subjectivities shaped through non‐Western European forms of imperialism; and (iii) connect racialised difference in Iran to the reproduction of colonial and racial logics vis‐à‐vis European imperialism.

Prognostic value of EMT-related genes and immune cell infiltration in thyroid carcinoma

BackgroundThe Epithelial–Mesenchymal Transition (EMT) is a very important process involved in cancer invasion and metastasis. Additionally, the Cathepsin K (CTSK) gene is closely related to the degradation of the extracellular matrix, which is a critical component of the EMT. The purpose of this study was to determine the relationships between EMT-related genes and immune cell infiltration and their prognostic value in Thyroid carcinoma (THCA). The effect of the CTSK gene on the aggressive biological features of THCA was assessed.MethodsWithin the framework of the present study, the THCA cohort was analyzed in detail based on data obtained from The TCGA database in the context of the EMT. The TCGA-THCA cohort was then divided into two groups, namely, high- and low-risk groups, based on the calculated EMT scores. Finally, based on the findings from the Weighted Gene Co-Expression Network Analysis (WGCNA) algorithm, LASSO regression analysis, and Kaplan−Meier plotter, we selected five genes (CTSK, C3ORF80, FBLN2, PRELP and SRPX2) associated with patient prognosis. Furthermore, this study examined the presence of various immune cells within the THCA samples using three distinct algorithms, namely ssGSEA, xCell, and MCPcounter. Additional studies have been conducted to establish the roles of CTSK in THCA cell proliferation and migration using various assays, such as CCK8, colony formation, EdU proliferation, Transwell migration and wound healing assays. Additionally, the involvement of CTSK in the regulation of various EMT-related markers was confirmed using Western blot analysis.ResultsBased on EMT scores, TCGA-THCA patients were further divided into two groups, and the study revealed that patients in the high-risk group had a worse prognosis than those in the low-risk group. Among the five genes linked to the prognostic value of EMT (CTSK, C3ORF80, FBLN2, PRELP, and SRPX2), CTSK exhibited notably elevated expression in the high-risk cohort. This group also exhibited pronounced immune cell infiltration, with a marked correlation observed between CTSK expression and the levels of macrophages, MDSCs, and various T-cell subtypes. Furthermore, in vitro studies demonstrated that reducing CTSK expression led to significant reductions in THCA cell viability; clonogenic, proliferative, motility and migratory capacities; and the expression of key EMT-related proteins, including N-cadherin, vimentin, slug, and snail.ConclusionOur results suggest that the expression of CTSK, a gene associated with the EMT, may be associated with THCA onset and progression and thus may serve as a promising prognostic biomarker.

Nuclear porcupine mediates XRCC6/Ku70 S-palmitoylation in the DNA damage response

BackgroundThe activation of the DNA damage response (DDR) heavily relies on post-translational modifications (PTMs) of proteins, which play a crucial role in the prevention of genetic instability and tumorigenesis. Among these PTMs, palmitoylation is a highly conserved process that is dysregulated in numerous cancer types. However, its direct involvement in the DDR and the underlying mechanisms remain unclear.MethodsCRISPR-Cas9 technology was used to generate the PORCN KO and PORCN NLS KO cell lines. The effects of PORCN NLS in the DDR were verified by colony formation assays, MTT assays, the DR/EJ5 homologous recombination/non-homologous end-joining reporter system, xenograft tumor growth and immunofluorescence. Mechanisms were explored by mass spectrometry, acyl-biotin exchange (ABE) palmitoylation assay, Click-iT assay, cell subcellular fractionation assay, Western blot analysis, and in vivo and in vitro co-immunoprecipitation.ResultsIn this study, we introduce evidence that Porcupine (PORCN) is an integral component of and plays a critical role in the DDR. PORCN deficiency hampers nonhomologous end joining (NHEJ) and highly sensitizes cells to ionizing radiation (IR) both in vitro and in vivo. We also provide evidence that PORCN possesses a nuclear fraction (nPORCN) with S-acyltransferase activity, unlike its membrane-bound O-acyltransferase in the endoplasmic reticulum. Furthermore, we show that nPORCN is necessary for the successful activation of NHEJ. Using mass spectrometry, we reveal the existence of an nPORCN complex and show that nPORCN mediates the S-palmitoylation of XRCC6/Ku70 at five specific cysteine sites in response to IR. Mutation of these sites causes a substantial increase in radiosensitivity and delays NHEJ. Additionally, we present evidence that nPORCN-dependent Ku70 palmitoylation is required for DNA-PKcs/Ku70/Ku80 complex formation.ConclusionOur findings underscore the crucial role of nPORCN-dependent Ku70 S-palmitoylation in the DDR.

Zymogen granule protein 16B (ZG16B) is a druggable epigenetic target to modulate the mammary extracellular matrix.

High tissue density of the mammary gland is considered a pro-tumorigenic factor, hence suppressing the stimuli that induce matrix buildup carries the potential for cancer interception. We found that in non-malignant mammary epithelial cells the combination of the chemopreventive agents bexarotene (Bex) and carvedilol (Carv) suppresses the zymogen granule protein 16B (ZG16B, PAUF) through an interaction of ARID1A with a proximal enhancer. Bex + Carv also reduced ZG16B levels invivo in normal breast tissue and MDA-MB231 tumor xenografts. The relevance of ZG16B is underscored by ongoing clinical trials targeting ZG16B in pancreatic cancers, but its role in breast cancer development is unclear. In immortalized mammary epithelial cells, secreted recombinant ZG16B stimulated mitogenic kinase phosphorylation, detachment and mesenchymal characteristics, and promoted proliferation, motility and clonogenic growth. Highly concerted induction of specific laminin, collagen and integrin isoforms indicated a shift in matrix properties toward increased density and cell-matrix interactions. Exogenous ZG16B alone blocked Bex + Carv-mediated control of cell growth and migration, and antagonized Bex + Carv-induced gene programs regulating cell adhesion and migration. In breast cancer cells ZG16B induced colony formation and anchorage-independent growth, and stimulated migration in a PI3K/Akt-dependent manner. In contrast, Bex + Carv inhibited colony formation, reduced Ki67 levels, ZG16B expression and glucose uptake in MDA-MB231 xenografts. These data establish ZG16B as a druggable pro-tumorigenic target in breast cell transformation and suggest a key role of the matrisome network in rexinoid-dependent antitumor activity.

The Role of the Bone Morphogenetic Protein Antagonist Noggin in Nucleus Pulposus Intervertebral Disc Cells

Low back pain (LBP) is a significant global health issue, contributing to disability and socioeconomic burdens worldwide. The degeneration of the human intervertebral disc (IVD) is a critical factor in the pathogenesis of LBP. Recent studies have emphasized the significance of a specific set of genes and extracellular matrix (ECM) in IVD health. In particular, Noggin has emerged as a critical gene due to its high expression levels in healthy nucleus pulposus cells (NPCs) observed in our previous research. In this study, it was hypothesized that decreased Noggin expression in NPCs is associated with IVD degeneration and contributes to LBP development. A lentivirus-mediated RNAi was applied to knock down Noggin expression in primary NPCs from six human donors. The NPCs after transduction were evaluated through cell viability analysis, XTT assay, and cell apoptosis analyses. After two weeks, a colony formation assay was used to examine the anchor-independent growth ability of transduced cells. At the transcript level, anabolic and catabolic markers were quantified using RT-qPCR. The results demonstrated that lentivirus-mediated downregulation of Noggin significantly inhibited cell proliferation, reduced cell viability, and suppressed colony formation, while inducing apoptosis in human NPCs in vitro. Notably, it disrupted cellular anabolic processes and promoted catabolic activity in human NPCs post-transduction. Our findings indicated that the degeneration of human IVD is possibly related to decreased Noggin expression in NPCs. This research provides valuable insights into the role of Noggin in IVD homeostasis and its implications in LBP treatment.

Vitamin K2 Protects Against SARS-CoV-2 Envelope Protein-Induced Cytotoxicity in Chronic Myeloid Leukemia Cells and Enhances Imatinib Activity

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm characterized by excessive proliferation of myeloid cells. The COVID-19 pandemic has raised concerns regarding the impact of SARS-CoV-2 on patients with malignancies, particularly those with CML. This study aimed to investigate the effects of SARS-CoV-2 proteins on CML cell viability and the protective role of vitamin K2 (VK2) in conjunction with imatinib. Experiments conducted on K562 CML cells demonstrated that the SARS-CoV-2 envelope protein induces cytotoxicity and activates caspase 3/7, which are key markers of apoptosis. VK2 mitigated these cytotoxic effects and decreased cytokine production while inhibiting colony formation. Furthermore, the combination of VK2 with imatinib significantly reduced cellular proliferation, diminished mitochondrial membrane potential, and markedly suppressed colony formation. These findings suggest that VK2 protects CML cells from SARS-CoV-2-induced cytotoxicity and enhances the therapeutic efficacy of imatinib, presenting a potential strategy to improve CML treatment during the COVID-19 pandemic.

GdX inhibits the occurrence and progression of breast cancer by negatively modulating the activity of STAT3

ABSTRACT Aim To elucidate the biological functionality and regulatory mechanisms of GdX in breast cancer (BC). Methods The examination of GdX expression in human BC tissues and cell lines was conducted through immunohistochemical (IHC) and Western blot. Cell proliferation capacity was assessed via the CCK-8 and colony formation assay, while cell migration was determined through the wound healing assay. The expression levels of BCL-XL, Cyclin D1, and C-myc gene were quantified using RT-qPCR and Western blot. In vivo tumor growth was evaluated in nude mice xenografted with MDA-MB-231 cells overexpressing GdX, and a mouse model with GdX-deficient BC was established to observe the impact of GdX on BC formation and metastasis. Dual-luciferase reporter assay and immunofluorescence were employed to confirm the interaction between GdX and STAT3. Western blot was employed to validate the influence of GdX overexpression on the phosphorylation process of STAT3. Results GdX exhibited low expression in the cancer tissues of BC patients and cell lines. MDA-MB-231 and MCF-7 cells overexpressing GdX displayed a notable reduction in proliferation and diminished migratory capabilities, accompanied by downregulated mRNA and protein expression of BCL-XL, Cyclin D1, and C-myc. In the xenograft mouse model, heightened GdX expression correlated with a decelerated in vivo tumor growth. Furthermore, in mice deteleing GdX, both the quantity and weight of tumors increased, along with evident pulmonary metastasis. Mechanistically, STAT3 emerged as a downstream target gene of GdX. Conclusions GdX exerts its inhibitory effects on the initiation and progression of BC by negatively modulating the phosphorylation of STAT3.

Integrated stress response-upregulated mitochondrial SLC1A5var enhances glucose dependency in human breast cancer cells in vitro

Breast cancer is the most commonly diagnosed cancer among women. The growth of triple-negative breast cancer (TNBC) cells is glucose-dependent. The integrated stress response (ISR) is a cellular stress response to glucose depletion. The ISR-solute carrier family 7 member 11 pathway is activated during glucose depletion and contributes to glucose dependence by decreasing intracellular glutamate levels. Solute carrier family 1 member 5 (SLC1A5) and the mitochondrial solute carrier family 1 member 5 variant (SLC1A5var) are glutamine transporters that play essential roles in the reprogramming of cancer metabolism. However, whether ISR can regulate mitochondrial SLC1A5var expression and further affect glucose dependence remains unclear. Glucose depletion-, oligomycin-, and salubrinal-activated activating transcription factor-4 (ATF4) induced SLC1A5var expression. ATF4 is critical for SLC1A5var regulation, as it binds to specific regulatory elements in its promoter. SLC1A5var knockdown decreases glucose depletion-induced cell death, whereas SLC1A5var overexpression increases glucose depletion-induced cell death in TNBC cells. SLC1A5var knockdown reduced cancer cell proliferation, colony formation, and migration, whereas SLC1A5var overexpression increased cell proliferation and migration. Moreover, the knockdown of SLC1A5var reduces the oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) while increasing the maximal OCR and ECAR under glucose depletion. These results suggest that activated ISR-induced increased expression of SLC1A5var may regulate mitochondrial oxidative phosphorylation and glycolytic metabolic characteristics to enhance glucose depletion-induced cell death. In conclusion, SLC1A5var plays a vital role in metabolic reprogramming and may be a potential target for breast cancer treatment.