This study aims to delve into the influences and underlying mechanisms of Banxia Xiexin Decoction(BXD) on the proliferation, apoptosis, invasion, and migration of colon cancer cells. Firstly, the components of BXD in blood were identified by UPLC-MS/MS, and subsequently the content of these components were determined by HPLC. Then, different concentrations of BXD were used to treat both the normal intestinal epithelial cells(NCM460) and the colon cancer cells(HT29 and HCT116). The cell viability and apoptosis were examined by the cell counting kit-8(CCK-8) and flow cytometry, respectively. Western blot was employed to determine the expression of the apoptosis regulators B-cell lymphoma-2(Bcl-2) and Bcl-2-associated X(Bax). The cell wound healing assay and Transwell assay were employed to measure the cell migration and invasion, respectively. Additionally, Western blot was employed to determine the expression levels of epithelial-mesenchymal transition(EMT)-associated proteins, including epithelial cadherin(E-cadherin), neural cadherin(N-cadherin), and vimentin. The protein and mRNA levels of the factors in the poly(ADP-ribose) glycohydrolase(PARG)/poly(ADP-ribose) polymerase 1(PARP1)/nuclear factor kappa-B p65(NF-κB p65) signaling pathway were determined by Western blot and RT-qPCR, respectively. The results demonstrated that following BXD intervention, the proliferation of HT29 and HCT116 cells was significantly reduced. Furthermore, BXD promoted the apoptosis, enhanced the expression of Bcl-2, and suppressed the expression of Bax in colon cancer cells. At the same time, BXD suppressed the cell migration and invasion and augmented the expression of E-cadherin while diminishing the expression of N-cadherin and vimentin. In addition, BXD down-regulated the protein and mRNA levels of PARG, PARP1, and NF-κB p65. In conclusion, BXD may inhibit the malignant phenotypes of colon cancer cells by mediating the PARG/PARP1/NF-κB signaling pathway.
Colonic Neoplasms/pathology* ; Drugs, Chinese Herbal/pharmacology* ; Phenotype ; Signal Transduction/drug effects* ; Cell Proliferation/drug effects* ; Apoptosis ; Cell Movement/drug effects* ; Neoplasm Invasiveness ; HCT116 Cells ; Proto-Oncogene Proteins c-bcl-2/biosynthesis* ; Humans ; Poly (ADP-Ribose) Polymerase-1 ; Glycoside Hydrolases ; bcl-2-Associated X Protein ; NF-kappa B p50 Subunit

OBJECTIVE: To investigate the effects of thymoquinone on the proliferation of acute myeloid leukemia (AML) cells and its molecular mechanism, so as to provide theoretical basis for the basic research on the anti-leukemia of traditional Chinese medicine. METHODS: The HL-60 and THP-1 cells were treated with thymoquinone at different concentration gradients, cell proliferation was detected by CCK-8 method, morphological changes were detected by Wright-Giemsa method, apoptosis was detected by Annexin V/PI double staining flow cytometry, and apoptosis and signal pathway protein expression were detected by Western blot. Real-time quantitative fluorescence PCR and Western blot were used to detect the expression changes of high mobility family members of SRY-related proteins (SOX). RESULTS: Thymoquinone inhibited the malignant proliferation of HL-60 and THP-1 cells, up-regulated the expression of pro-apoptotic protein Bax, down-regulated the expression of anti-apoptotic protein Bcl-2 and Survivin, and hydrolyzed Caspase-3 to induce the apoptosis of HL-60 and THP-1 cells. Thymoquinone could also significantly down-regulate the phosphorylation of PI3K, Akt and mTOR, and inhibit the malignant biological characteristics of HL-60 and THP-1 cells by inhibiting the activation of PI3K/Akt/mTOR pathway. After thymoquinone intervention in HL-60 and THP-1 cells, the expression of SOX2 and SOX4 could be down-regulated significantly. At low concentration ( < 10 μmol/L), the expression of SOX12 was weakly affected by thymoquinone. With increasing concentration, the expression of SOX12 could be down-regulated, however, thymoquinone had no effect on SOX11 expression. CONCLUSION Thymoquinone can inhibit the proliferation of AML cells, and its mechanism may be related to inhibiting the activation of PI3K/Akt/mTOR signaling pathway, regulating the expression of apoptotic proteins and core members of SOX family.
Humans ; Benzoquinones/pharmacology* ; Cell Proliferation/drug effects* ; Leukemia, Myeloid, Acute/metabolism* ; Apoptosis/drug effects* ; HL-60 Cells ; Signal Transduction/drug effects* ; Proto-Oncogene Proteins c-akt/metabolism* ; TOR Serine-Threonine Kinases/metabolism* ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; bcl-2-Associated X Protein/metabolism* ; Cell Line, Tumor ; Phosphatidylinositol 3-Kinases/metabolism* ; THP-1 Cells

OBJECTIVE: To establish venetoclax-resistant acute myeloid leukemia (AML) cell lines, assess the sensitivity of venetoclax-resistant cell lines to the BCL-2 protein family, and investigate their resistance mechanisms. METHODS: CCK-8 method was used to screen AML cell lines (MV4-11, MOLM13, OCI-AML2) that were relatively sensitive to venetoclax. Low concentrations of venetoclax continuously induced drug-resistance development in the cell lines. Changes in cell viability and apoptosis rate before and after resistance development were measured using the CCK-8 method and flow cytometry. BH3 profiling assay was performed to anayze the transform of mitochondrion-dependent apoptosis pathway as well as the sensitivity of resistant cell lines to BCL-2 family proteins and small molecule inhibitors. Real-time fluorescence quantitative PCR (RT-qPCR) was utilized to examine changes in the expression levels of BCL-2 protein family members in both venetoclax-resistant cell lines and multidrug-resistant patients. RESULTS: Venetoclax-resistant cell lines of MV4-11, MOLM13, and OCI-AML2 were successfully established, with IC₅₀ values exceeding 10-fold. Under the same concentration of venetoclax, the apoptosis rate of resistant cells decreased significantly (P < 0.05). BH3 profiling assay revealed that the drug-resistant cell lines showed increased sensitivity to many pro-apoptotic proteins (such as BIM,BID and NOXA). RT-qPCR showed significantly upregulated MCL1 and downregulated NOXA1 were detected in drug-resistant cell lines. Expression changes in MCL1 and NOXA1 in venetoclax-resistant patients were consistent with our established drug-resistant cell line results. CONCLUSION The venetoclax-resistant AML cell lines were successfully established through continuous induction with low concentrations of venetoclax. The venetoclax resistance resulted in alterations in the mitochondrial apoptosis pathway of the cells and an increased sensitivity of cells to pro-apoptotic proteins BIM, BID, and NOXA, which may be associated with the upregulation of MCL1 expression and downregulation of NOXA1 expression in the drug-resistant cells.
Humans ; Sulfonamides/pharmacology* ; Drug Resistance, Neoplasm ; Bridged Bicyclo Compounds, Heterocyclic/pharmacology* ; Leukemia, Myeloid, Acute/pathology* ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Cell Line, Tumor ; Apoptosis ; Antineoplastic Agents/pharmacology*

OBJECTIVE: To explore the molecular mechanism of Shenmai Injection (SMI) against doxorubicin (DOX) induced cardiomyocyte apoptosis. METHODS: A total of 40 specific pathogen-free (SPF) male Sprague Dawley (SD) male rats were divided into 5 groups based on the random number table, including the control group, the model group, miR-30a agomir group, SMI low-dose (SMI-L) group, and SMI high-dose (SMI-H) group, with 8 rats in each group. Except for the control group, the rats were injected weekly with DOX (2 mg/kg) in the tail vein for 4 weeks to induce myocardial injury, and were given different regimens of continuous intervention for 2 weeks. Cardiac function was detected by echocardiography and myocardial pathological changes were observed by Van Gieson (VG) staining. Myocardial injury serum markers, including creatine kinase (CK), lactate dehydrogenase (LDH), troponin T (cTnT), N-terminal pro-brain natriuretic peptide (NT-proBNP), soluble ST2 (sST2), and growth differentiation factor-15 (GDF-15) were detected by enzyme linked immunosorbent assay (ELISA). Cardiomyocyte apoptosis was observed by terminal deoxynucleotidyl transferase-mediated biotinylated dUTP triphosphate nick end labeling (TUNEL) and transmission electron microscopy, and the expressions of target proteins and mRNA were detected by Western blot and quantitative real time polymerase chain reaction (qRT-RCR), respectively. RESULTS: The treatment with different doses of SMI reduced rat heart mass index and left ventricular mass index (P<0.05), significantly improved the left ventricular ejection fraction (P<0.05), decreased the levels of serum CK, LDH, cTnT, and NT-proBNP (P<0.05 or P<0.01), reduced the levels of serum sST2 and GDF-15 (P<0.05 or P<0.01), decreased the collagen volume fraction, reduced the expressions of rat myocardial type I and type III collagen (P<0.05 or P<0.01), and effectively alleviated myocardial fibrosis. And the study found that SMI promoted the expression levels of miR-30a and Bcl-2 in myocardium, and down-regulated the expression of Bax, which inhibited the activation of Caspase-3 and Caspase-9 (P<0.05 or P<0.01), and improved myocardial cell apoptosis. CONCLUSIONS SMI can alleviate myocardial injury and apoptosis caused by DOX, and its mechanism possibly by promoting the targeted expression of myocardial Bcl-2 protein through miR-30a.
Animals ; Myocytes, Cardiac/metabolism* ; Apoptosis/drug effects* ; MicroRNAs/genetics* ; Rats, Sprague-Dawley ; Male ; Drugs, Chinese Herbal/administration & dosage* ; Doxorubicin/pharmacology* ; Proto-Oncogene Proteins c-bcl-2/genetics* ; Drug Combinations ; Injections ; Rats

OBJECTIVES: Oxaliplatin (OXA) and 5-fluorouracil (5-FU) are 2 commonly used chemotherapeutic agents for colorectal cancer (CRC). MicroRNAs (miRNAs, miRs) play crucial roles in the development of chemoresistance in various cancers. However, the role and mechanism of miR-224-5p in regulating CRC chemoresistance remain unclear. This study aims to investigate the function of miR-224-5p in chemoresistant CRC cells and the underlying mechanisms. METHODS: CRC datasets GSE28702 and GSE69657 were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed miRNAs between drug-sensitive and resistant groups (OXA or 5-FU) were analyzed, and miR-224-5p was identified as the target miRNA. Chemoresistant cell lines HCT15-OXR, HCT15-5-FU, SW480-OXR, and SW480-5-FU were established. Transient transfections were performed using miR-224-5p mimics, inhibitors, and their respective negative controls (control mimic, control inhibitor) in these cell lines. Cells were treated with different concentrations of OXA or 5-FU post-transfection, and the half-maximal inhibitory concentration (IC₅₀) was determined using the cell counting kit-8 (CCK-8) assay. Cell proliferation was assessed by CCK-8 and colony formation assays. The expression levels of miR-224-5p, LC3, and P62 were measured by real-time polymerase chain reaction (real-time PCR) and/or Western blotting. Autophagic flux was assessed using a tandem fluorescent-tagged LC3 reporter assay. TargetScan 8.0, miRTarBase, miRPathDB, and HADb were used to predict B-cell lymphoma-2 (Bcl-2) as a potential miR-244-5p target, which was further validated by dual-luciferase reporter assays. RESULTS: Chemoresistant CRC cells exhibited down-regulated miR-224-5p expression, whereas up-regulation of miR-224-5p enhanced chemotherapy sensitivity. Exposure to OXA or 5-FU significantly increased autophagic activity in chemoresistant CRC cells, which was reversed by miR-224-5p overexpression. Dual-luciferase assays verified Bcl-2 as a direct target of miR-224-5p. CONCLUSIONS MiR-224-5p regulates chemoresistance in CRC by modulating autophagy through direct targeting of Bcl-2.
Humans ; MicroRNAs/physiology* ; Colorectal Neoplasms/drug therapy* ; Drug Resistance, Neoplasm/genetics* ; Autophagy/drug effects* ; Fluorouracil/pharmacology* ; Oxaliplatin ; Cell Line, Tumor ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Gene Expression Regulation, Neoplastic

Pristimerin, which is one of the compounds present in Celastraceae and Hippocrateaceae, has antitumor effects. However, its mechanism of action in esophageal squamous cell carcinoma (ESCC) remains unclear. This study aims to investigate the efficacy and mechanism of pristimerin on ESCC in vitro and in vivo. The inhibitory effect of pristimerin on cell growth was assessed using trypan blue exclusion and colony formation assays. Cell apoptosis was evaluated by flow cytometry. Gene and protein expressions were analyzed through quantitative reverse transcription-polymerase chain reaction (qRT-PCR), Western blotting, and immunohistochemistry. RNA sequencing (RNA-Seq) was employed to identify significantly differentially expressed genes (DEGs). Cell transfection and RNA interference assays were utilized to examine the role of key proteins in pristimerin?s effect. Xenograft models were established to evaluate the antitumor efficiency of pristimerin in vivo. Pristimerin inhibited cell growth and induced apoptosis in ESCC cells. Upregulation of Noxa was crucial for pristimerin-induced apoptosis. Pristimerin activated the Forkhead box O3a (FoxO3a) signaling pathway and triggered FoxO3a recruitment to the Noxa promoter, leading to Noxa transcription. Blocking FoxO3a reversed pristimerin-induced Noxa upregulation and cell apoptosis. Pristimerin treatment suppressed xenograft tumors in nude mice, but these effects were largely negated in Noxa-KO tumors. Furthermore, the chemosensitization effects of pristimerin in vitro and in vivo were mediated by Noxa. This study demonstrates that pristimerin exerts an antitumor effect on ESCC by inducing AKT/FoxO3a-mediated Noxa upregulation. These findings suggest that pristimerin may serve as a potent anticancer agent for ESCC treatment.
Forkhead Box Protein O3/genetics* ; Humans ; Apoptosis/drug effects* ; Esophageal Squamous Cell Carcinoma/physiopathology* ; Esophageal Neoplasms/physiopathology* ; Pentacyclic Triterpenes ; Animals ; Cell Line, Tumor ; Proto-Oncogene Proteins c-bcl-2/genetics* ; Mice ; Signal Transduction/drug effects* ; Mice, Nude ; Cell Proliferation/drug effects* ; Triterpenes/pharmacology* ; Xenograft Model Antitumor Assays ; Mice, Inbred BALB C ; Male ; Gene Expression Regulation, Neoplastic/drug effects*

This paper investigated the mechanism of Huoxue Dingxuan Capsules(HXDX) on autophagy in vascular endothelial cells based on the "crosstalk" of Bcl-2 and mTOR protein. bEnd.3 cells were divided into a blank control group, a model group, and an HXDX group. CO-IP experiments were conducted, and then Western blot(WB) was used to detect the binding of Bcl-2 and mTOR. Co-localization of Bcl-2 with mTOR protein was observed by laser confocal microscopy after staining. The model of Bcl-2 siRNA in bEnd.3 cells was constructed, and the bEnd.3 cells were divided into five groups, including blank control group, oxygen-glucose deprivation(OGD) group, transfected Bcl-2 siRNA group, negative control(NC) group, and HXDX group. The model of mTOR siRNA in bEnd.3 cells was constructed, and the bEnd.3 cells were divided into five groups, including blank control group, OGD group, transfected mTOR siRNA group, NC group, and HXDX group. The expression of autophagy-related proteins was detected by WB. The results of CO-IP experiments showed that Bcl-2 and mTOR proteins could be co-localized and expressed in bEnd.3 cells, and the expression of Bcl-2 and mTOR proteins increased after the intervention of the HXDX-containing serum. After screening and transfection with Bcl-2-mus-384, autophagy of bEnd.3 cells was induced. The expression of Bcl-2 in the Bcl-2 siRNA group was significantly decreased compared with the blank control group and model group. The expression of mTOR protein was significantly lower than that of the OGD group, and the expression of human microtubule-associated protein light chain 3Ⅱ/Ⅰ was significantly higher than that of the model group. After the intervention of the HXDX-containing serum, the expression of Bcl-2 and mTOR was increased in the HXDX group compared with that in the Bcl-2 siRNA group, and the expression of LC3Ⅱ/LC3Ⅰ and Beclin1 was decreased in the HXDX group compared with that in the Bcl-2 siRNA group. After transfecting mTOR-mus-7061 and inducing autophagy of bEnd.3 cells, in the mTOR siRNA group, mTOR protein expression was decreased compared with the blank control and model groups, and LC3Ⅱ/LC3Ⅰ and Beclin1 protein expression was increased compared with the model group. After the intervention of the HXDX-containing serum, the expression of Bcl-2 and mTOR was increased in the HXDX group compared with that in the mTOR siRNA group, and the expression of LC3Ⅱ/LC3Ⅰ and Beclin1 proteins was decreased compared with the mTOR siRNA group. This study explored the "crosstalk" of Bcl-2 and mTOR during autophagy in bEnd.3 cells at the cellular level and illustrated the modulating effect of the HXDX-containing serum, which provided a basis for the treatment of cervical spondylosis of vertebral artery type.
Autophagy/drug effects* ; TOR Serine-Threonine Kinases/genetics* ; Drugs, Chinese Herbal/pharmacology* ; Endothelial Cells/metabolism* ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Animals ; Mice ; Capsules ; Humans

This study aimed to investigate the effect of aucubin(AU) on injury of nucleus pulposus cells and extracellular matrix(ECM) degradation and its mechanism. The nucleus pulposus cell injury model was established by interleukin-1β(IL-1β) and treated with AU or phosphatidylinositol 3-kinase(PI3K) inhibitor LY294002. CCK-8 experiment was conducted to test cell proliferation. EdU staining method was employed to detect cell injury. Flow cytometry was used to detect cell apoptosis. Western blot was used to detect protein levels of cleaved-caspase-3, B-cell lymphoma(Bcl-2), Bcl-2 associated X protein(Bax), type Ⅱ collagen(collagen Ⅱ), aggregation proteoglycans(aggrecan), PI3K, and mammalian target of rapamycin(mTOR). qPCR was used to detect the rRNA level of 5S, 18S, and 28S. Ethynyluridine was used to label nascent RNA. The results showed that IL-1β could significantly cause injury of nucleus pulposus cells and increase the apoptosis rate of nucleus pulposus cells and the expression of apoptosis protein cleaved-caspase-3 and Bax. At the same time, IL-1β down-regulated the expression of anti-apoptotic protein Bcl-2 and collagen Ⅱ and aggrecan, the main components of ECM. On this basis, AU intervention could improve the injury of nucleus pulposus cells, reduce the apoptosis of nucleus pulposus cells and the expression of cleaved-caspase-3 and Bax, and increase the expression of Bcl-2, collagen Ⅱ, and aggrecan. Compared with IL-1β, AU could up-regulate the phosphorylation level of PI3K and mTOR, and LY294002 could reverse the injury of nucleus pulposus cells and improve ECM degradation induced by AU. In addition, AU also could save lowered rRNA levels of 5S, 18S, and 28S induced by IL-1β and improve RNA synthesis. PI3K inhibitor LY294002 intervention could reduce the promoting effect of AU on ribosome biogenesis. The above results suggest that AU can improve the injury of nucleus pulposus cells and ECM degradation, and its mechanism of action is related to its activation of the PI3K/mTOR pathway to promote ribosome biogenesis.
Nucleus Pulposus/cytology* ; Extracellular Matrix/drug effects* ; Animals ; Iridoid Glucosides/pharmacology* ; Apoptosis/drug effects* ; Interleukin-1beta/metabolism* ; Phosphatidylinositol 3-Kinases/genetics* ; Rats ; Cell Proliferation/drug effects* ; TOR Serine-Threonine Kinases/genetics* ; Rats, Sprague-Dawley ; Humans ; Signal Transduction/drug effects* ; Caspase 3/genetics* ; Proto-Oncogene Proteins c-bcl-2/genetics*

This study aims to investigate the protective effect of resveratrol against liver injury in hindlimb unloading rats. Thirty 2-month-old male SD rats were randomly divided into normal group (Control), hindlimb unloading model group (Model), and hindlimb unloading+resveratrol administration group (Model+Res). The Model + Res group was injected intraperitoneally with 30 mg/kg of resveratrol, and the Control and Model groups were injected intraperitoneally with an equal volume of 0.9% NaCl. Liver tissues were collected after 28 days and analyzed for oxidative stress, inflammatory factors, energy metabolism indices, Na ⁺-K ⁺-ATPase and Ca ²⁺-Mg ²⁺-ATPase activity, and morphological changes were observed by hematoxylin-eosin staining. The protein expression levels of Bax, Bcl-2, p-PI3K, PI3K, p-AKT, and AKT were detected by Western blotting. Compared with the Control group, hepatocytes in the Model group showed swelling, abnormal morphology, nuclear consolidation, and cell membrane disruption. Oxidative stress, inflammatory factor levels, hepatic glycogen accumulation, and energy metabolism were increased in the liver tissues of the Model group, while resveratrol treatment significantly reversed these changes. The results of Western blotting showed that resveratrol significantly reduced the expression of Bax and increased the expression levels of Bcl-2, and the proteins of p-PI3K/PI3K and p-AKT/AKT expression levels. It is suggested that 28 days of hindlimb unloading treatment could lead to liver tissue injury in rats, which is manifested as oxidative stress, inflammatory response, energy metabolism disorder and increased apoptosis level, and resveratrol has a certain mitigating effect on this.
Animals ; Resveratrol ; Male ; Liver/pathology* ; Rats, Sprague-Dawley ; Rats ; Hindlimb Suspension ; Oxidative Stress/drug effects* ; Phosphatidylinositol 3-Kinases/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; Stilbenes/pharmacology* ; bcl-2-Associated X Protein/metabolism* ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Apoptosis/drug effects*

This study aims to investigate the effect and mechanism of saikosaponin D on the proliferation, apoptosis, and autophagy of pancreatic cancer Panc-1 cells. The cell counting kit(CCK-8) was used to examine the effects of 7, 10, 13, 16, 19, 22, 25, and 28 μmol·L~(-1) saikosaponin D on the proliferation of Panc-1 cells. Three groups including the control(0 μmol·L~(-1)), low-concentration(10 μmol·L~(-1)) saikosaponin D, and high-concentration(16 μmol·L~(-1)) saikosaponin D groups were designed. The colony formation assay was employed to measure the effect of saikosaponin D on the colony formation rate of Panc-1 cells. The cells treated with saikosaponin D were stained with hematoxylin-eosin(HE), and the changes of cell morphology were observed. Hoechst 33258 fluorescent staining was used to detect the effect of saikosaponin D on the cell apoptosis. The autophagy staining assay kit with MDC was used to examine the effect of saikosaponin D on the autophagy of Panc-1 cells. Western blot and immunocytochemistry(ICC) were employed to examine the effect of saikosaponin D on the expression levels and distribution of B-cell lymphoma-2(Bcl-2), Bcl-2-associated X protein(Bax), cysteine-aspartic acid protease-3(caspase-3), cleaved caspase-3, autophagy-associated protein Beclin1, microtubule-associated protein light chain 3(LC3), protein kinase B(Akt), phosphorylated protein kinase B(p-Akt), mammalian target of rapamycin(mTOR), and phosphorylated mammalian target of rapamycin(p-mTOR). The results showed that compared with the control group, saikosaponin D decreased the proliferation rate of Panc-1 cells in a dose-dependent and time-dependent manner. The colony formation rate of the cells significantly decreased after saikosaponin D treatment. Compared with the control group, the cells treated with saikosaponin D became small, accompanied by the formation of apoptotic bodies. The saikosaponin D groups showed increased apoptosis rate and autophagic vesicle accumulation. Compared with the control group, saikosaponin D up-regulated the expression of Bax, cleaved caspase3, Beclin1, LC3Ⅱ/LC3Ⅰ and down-regulated the expression of Bcl-2, caspase-3, p-Akt/Akt, and p-mTOR/mTOR. In addition, these proteins mainly existed in the cytoplasm. In conclusion, saikosaponin D can inhibit the proliferation and induce the apoptosis and autophagy of Panc-1 cells via inhibiting the Akt/mTOR pathway.
Humans ; Proto-Oncogene Proteins c-akt/genetics* ; Caspase 3 ; bcl-2-Associated X Protein ; Beclin-1/pharmacology* ; Cell Line, Tumor ; TOR Serine-Threonine Kinases/genetics* ; Apoptosis ; Pancreatic Neoplasms/drug therapy* ; Caspases ; Autophagy