Levels Of Pro-apoptotic Proteins Research Articles

Neuregulin 4 attenuates pancreatic β-cell apoptosis induced by lipotoxicity via activating mTOR-mediated autophagy

ABSTRACT Neuregulin 4 (Nrg4) is a brown fat-enriched endocrine factor that ameliorates lipid metabolism disorders. Autophagy is critical for pancreatic β-cell to counteract lipotoxicity-induced apoptosis. This study aimed at exploring whether Nrg4 attenuates lipotoxicity-induced β-cell apoptosis by regulating autophagy. The mouse pancreatic β-cell line MIN6 was cultured in palmitic acid (PA) with or without Nrg4 administration. Apoptosis rate, together with anti-apoptotic and pro-apoptotic protein levels, was investigated. Autophagic flux and autophagy-related protein levels along with related signaling pathways that regulate autophagy were also evaluated. Results showed that Nrg4 decreased PA-induced MIN6 apoptosis, enhanced anti-apoptotic protein B-cell lymphoma 2 (Bcl-2) expression and reduced pro-apoptotic proteins Bcl-2-associated X protein (Bax) and cleaved-caspase 3 expressions. Autophagy levels in MIN6 also decreased with PA treatment and Nrg4 administration reactivated autophagy. Further, Nrg4 administration activated autophagy via the mammalian target of rapamycin (mTOR) signaling pathway. In addition, when the mTOR pathway was stimulated or autophagy was suppressed, the beneficial effects of Nrg4 administration on MIN6 apoptosis were diminished. These results imply that Nrg4 administration attenuates MIN6 apoptosis by promoting mTOR-dependent autophagy and thus may lead to a new therapeutic method for type 2 diabetes mellitus (T2DM).

ETFDH mutation involves excessive apoptosis and neurite outgrowth defect via Bcl2 pathway

The most common mutation in southern Chinese individuals with late-onset multiple acyl-coenzyme A dehydrogenase deficiency (MADD; a fatty acid metabolism disorder) is c.250G > A (p.Ala84Thr) in the electron transfer flavoprotein dehydrogenase gene (ETFDH). Various phenotypes, including episodic weakness or rhabdomyolysis, exercise intolerance, and peripheral neuropathy, have been reported in both muscular and neuronal contexts. Our cellular models of MADD exhibit neurite growth defects and excessive apoptosis. Given that axonal degeneration and neuronal apoptosis may be regulated by B-cell lymphoma (BCL)-2 family proteins and mitochondrial outer membrane permeabilization through the activation of proapoptotic molecules, we measured the expression levels of proapoptotic BCL-2 family proteins (e.g., BCL-2-associated X protein and p53-upregulated modulator of apoptosis), cytochrome c, caspase-3, and caspase-9 in NSC-34 cells carrying the most common ETFDH mutation. The levels of these proteins were higher in the mutant cells than in the wide-type cells. Subsequent treatment of the mutant cells with coenzyme Q10 downregulated activated protein expression and mitigated neurite growth defects. These results suggest that the activation of the BCL-2/mitochondrial outer membrane permeabilization/apoptosis pathway promotes apoptosis in cellular models of MADD and that coenzyme Q10 can reverse this effect. Our findings aid the development of novel therapeutic strategies for reducing axonal degeneration and neuronal apoptosis in MADD.

Role of layilin in regulating mitochondria-mediated apoptosis: a study on B cell lymphoma (BCL)-2 family proteins

BackgroundMalignant gliomas exhibit rapid tumor progression and resistance to treatment, leading to high lethality. One of the causes is the reduced progression of apoptosis in glioma cells. Layilin is a type 1 transmembrane protein with a C-type lectin motif in its extracellular domain. We previously reported that layilin is mainly localized to mitochondria or their close proximity and that layilin is essential for maintaining of the fragmented type of mitochondria. This study investigates the effects of layilin on mitochondria-mediated apoptosis, focusing on B cell lymphoma (BCL)-2 family proteins in a glioma cell line of A172 cells.ResultsWe compared the levels of pro-apoptotic BCL-2 family proteins of BAD, BAK, BAX, and BIM and anti-apoptotic BCL-2 family proteins of BCL-2 and BCL-XL between layilin- knockdown (KD) cells and control cells using western blot. The protein levels of BAD were significantly smaller in layilin-KD cells than in control cells, while those of BCL-2 were significantly larger. We then compared the mitochondrial membrane potential (ΔΨm) under p-trifluoromethoxyphenyl hydrazone (FCCP)-treated conditions using MT-1 staining. In layilin-KD cells, ΔΨm was significantly larger and FCCP-induced ΔΨm reduction was significantly lower than in control cells. Furthermore, we examined the levels of cell membrane-bound Annexin V and DNA-bound propidium idodide (PI) in layilin-KD cells with/without staurosporine (STS) treatment. Layilin-KD significantly decreased levels of cell membrane-bound Annexin V with/without STS treatment. On the other hand, PI levels were not changed by layilin-KD. We also investigated the amounts of the active caspase (CASP)-3, CASP-6, CASP-7, and poly (ADP-ribose) polymerase-1 (PARP1, cleaved form), as well as DNA fragmentation in layilin-KD cells under apoptotic conditions induced by STS, using western blot and the DNA ladder method, respectively. Under STS-treated conditions, the amounts of active CASP-3, CASP-7, and poly (ADP-ribose) PARP1 were significantly smaller in layilin-KD cells than in control cells. Accordingly, DNA fragmentation was significantly suppressed in layilin-KD cells compared to control cells under STS-treated conditions.ConclusionThis study demonstrates that layilin contributes to ΔΨm reduction to promote apoptosis by up-regulating BAD and down-regulating BCL-2 in glioma cells. Our data elucidates a new function of layilin: regulation of mitochondria-mediated apoptosis.

Gochujang suppresses cell survival and changes reactive oxygen species metabolism in colorectal cancer cells.

There is a significant global increase in colorectal cancer (CRC) among young adults. Gochujang, one of the signature Korean traditional fermented foods, contains various bioactive compounds and has multiple health-beneficial effects, including anticancer effects; however, the detailed cellular and molecular mechanisms of its anticancer outcomes are not fully understood. The objective of the present study was to investigate the detailed underlying anticancer mechanisms of Gochujang in CRC cells. Gochujang was extracted with 80% ethanol, and total polyphenol contents (9.9 ± 1.63 mgGAE/g) and total flavonoid contents (0.14 ± 0.07 mgQE/g) of Gochujang extract (GE) were evaluated. GE significantly suppressed cell viability, migration, and colony formation in CRC cells. Also, GE increased the cell cycle arrest-related protein p21 level, whereas it decreased cell cycle progression-associated proteins, such as p-Rb. Moreover, GE markedly elevated the levels of proapoptotic proteins (e.g. Bim and c-PARP), while it downregulated antiapoptotic protein expressions (e.g. Bcl-2 and Bcl-xL). GE also altered the expression of the autophagy-involved proteins. Furthermore, GE strongly reduced the expression of major antioxidant enzymes and increased the reactive oxygen species (ROS) generation in CRC cells, causing an imbalance of ROS metabolism. In conclusion, this study demonstrated that Gochujang exerts anticancer effects in CRC cells by inhibiting cell proliferation, increasing cell death, and interrupting ROS metabolism.

Inhibition of phosphodiesterase 10A mitigates neuronal injury by modulating apoptotic pathways in cold-induced traumatic brain injury

Brain injury develops from a complex series of pathophysiological phases, resulting in acute necrotic or delayed apoptotic cell death after traumatic brain injury (TBI). Inhibition of apoptotic cell death is critical for the treatment of acute neurodegenerative disorders, such as TBI. Here, we investigated the role of phosphodiesterase 10A (PDE10A) in the development of neuronal injury, particularly in apoptotic cell death. Using the PDE10A inhibitor TAK-063, we found that PDE10A inhibition is associated with decreased brain injury, brain swelling, and blood brain barrier disruption 48 h after cold-induced TBI. Furthermore, a particularly notable result was observed with 3 mg/kg TAK-063, which reduced disseminated neuronal injury. Protein abundance analysis revealed that PDE10A inhibition activates survival kinases AKT and ERK-1/-2, which were associated with the decreased activation of MMP-9 and PTEN. Additionally, iNOS and nNOS levels significantly reduced in the TAK-063 group, playing roles in inflammation and apoptosis. A planar surface immunoassay was performed for in-depth analyses of the apoptotic signaling pathways. We observed that inhibition of PDE10A resulted in the decreased expression of TNFRSF1A, TNFRSF10B, and TNFRSF6 receptors, particularly inducing apoptotic cell death. Moreover, these findings correlated with reduced levels of pro-apoptotic proteins, including PTEN, p27, Cytochrome-c, cleaved Caspase-3, Bad, and p53. Interestingly, TAK-063 treatment reduced levels of anti-apoptotic proteins or enzymes, including XIAP, Claspin, and HIF1α, without affecting Bcl-x, MCL-1, SMAC, HO-1, HO-2, HSP27, HSP60, and HSP70. The findings suggest that PDE10A regulates cellular signaling predominantly pro-apoptotic pathways, and inhibition of this protein is a promising approach for the treatment of acute brain injury.

The Apoptotic, Cytotoxic, and Anti-migration Effects of Sodium Deoxycholate in a Breast Cancer Cell Line and its Modulation on PON1 as a Predictive Risk Marker.

Breast cancer is the most prevalent cancer among women and is usually treated with antineoplastic drugs. The present study examines the influence of sodium deoxycholate on the molecular pathways underlying apoptosis, cytotoxicity, and the modulation of PON1 in the MCF-7 breast cancer cell line. Various doses were administered to test the hypothesis that it could potentially affect cancer cells. The study examined the cytotoxic effect of sodium deoxycholate on MCF-7 cells and human mammary epithelial cells (CRL-4010) using the MTT method to detect its anticancer properties. Subsequently, the efficacy of the active dose on DNA fragmentation and apoptosis was examined using the apoptotic DNA ladder and Western blot methods. Additionally, oxidative stress index and cell migration tests were conducted. Notably, sodium deoxycholate did not cause DNA damage despite demonstrating cytotoxic effects on cells. The study found that sodium deoxycholate increased the levels of several pro-apoptotic proteins, leading to apoptosis. Moreover, it markedly diminishes the activity of paraoxonase and arylesterase of PON1, which are predictive risk markers for cancer. Furthermore, it was found to delay cell migration in a time-dependent manner. These findings suggest that sodium deoxycholate exhibits an antimetastatic effect in breast cancer cells, could be a valuable subject for further cancer research.

Sodium diethyldithiocarbamate trihydrate: an effective and selective compound for hematological malignancies.

Myeloid leukemias and lymphomas are among the most common and well-studied hematological malignancies. However, due to the aggressiveness and rapid progression of certain subtypes, treating these diseases remains a challenge. Considering the promising results of diethyldithiocarbamates in preclinical and clinical oncology trials, this study aimed to investigate the potential of sodium diethyldithiocarbamate trihydrate (DETC) as a prototype for developing new drugs to treat hematological malignancies. In silico analysis using SwissADME was conducted to evaluate the physicochemical characteristics and pharmacokinetic properties of DETC. An in vitro investigation utilizing the MTT assay assessed the cytotoxic effects of DETC on neoplastic and non-neoplastic cell lines. Selectivity was determined using a selectivity index and a hemolysis assay, while the mechanism of cell death in neoplastic cell lines was examined through flow cytometry analysis of pro-apoptotic and anti-apoptotic protein levels. The results demonstrated that the physicochemical characteristics of DETC are suitable for oral administration. Furthermore, the compound showed promising cytotoxic activity against human myeloid leukemia (K562) and Burkitt's lymphoma (Daudi) cell lines, with high selectivity for neoplastic cells over non-neoplastic cells of the bone marrow microenvironment (HS-5 cell line). Moreover, hemolysis was observed only at very high concentrations. The cytotoxicity mechanism of DETC against both neoplastic cell lines involved cell cycle arrest and the production of reactive oxygen species. In K562 cells, cell death was induced via apoptosis. Additional experiments are needed to confirm the exact mechanism of cell death in Daudi Burkitt's lymphoma cells.

Fractionated Leaf Extracts of Ocimum gratissimum Inhibit the Proliferation and Induce Apoptosis of A549 Lung Adenocarcinoma Cells.

Previous in vitro studies in our laboratory demonstrated that ethyl acetate (P2) and water- soluble (PS/PT1) fractionated leaf extracts of Ocimum gratissimum inhibit the proliferation of prostate cancer cells. It has been reported that the crude aqueous extract induces apoptosis in lung adenocarcinoma cells; however, the efficacy of the fractionated extracts against these cells remains unclear. In the present study, we hypothesized that the ability of the fractionated extracts to inhibit proliferation and induce apoptosis is associated with the activation of pro-apoptotic proteins and induction of DNA condensation in A549 cells. Ocimum gratissimum was cultivated and its leaves were harvested, extracted, and fractionated to produce fractions P2 and PS/PT1. Anti-proliferative activity was assessed by direct cell count. For morphological characterization of apoptosis, 4',6-diamidino-2-phenylindole staining was employed. Western blot analysis was performed to evaluate the apoptotic activity of the fractionated extracts. In data generated from anti-proliferation studies, P2 significantly inhibited cell proliferation in a concentration-dependent manner; PS/PT1 elicited a decrease in the viability of cells, occurring at 500 µg/mL. 4',6-diamidino-2-phenylindole staining revealed the induction of apoptosis, as evidenced by the formation of apoptotic bodies. Increased levels of pro-apoptotic proteins were observed as the concentrations of the fractionated extracts increased. These results suggest that fractionated leaf extracts of Ocimum gratissimum inhibit the proliferation and induce apoptosis of A549 cells.

Lithium-induced apoptotic cell death is not accompanied by a noticeable inflammatory response in the kidney.

Lithium (Li+) therapy is a valuable tool in psychiatric practice that remains underutilized due to safety concerns. Excessive plasma Li+ levels are nephrotoxic and can trigger a local immune response. Our understanding of the immunomodulatory effects of Li+ in the kidney is fragmentary. Here, we studied how immune mechanisms contribute to the development of Li+-induced adverse effects in the kidneys of C57BL/6NJ mice placed on a 0.3% lithium carbonate diet for 28days. We combined histochemical techniques, immunoblotting, flow cytometry, qPCR and proteome profiler arrays to characterize renal tissue damage, infiltrating immune cells and cytokine markers, activation of pyroptotic and apoptotic cascades in the kidneys of mice receiving Li+-containing and regular diets. We found that biomarkers of tubular damage, kidney injury marker, KIM-1, and neutrophil gelatinase-associated lipocalin, NGAL, were elevated in the renal tissue of Li+-treated mice when compared to controls. This correlated with increased interstitial fibrosis in Li+-treated mice. Administration of Li+ did not activate the pro-inflammatory NLRP3 inflammasome cascade but promoted apoptosis in the renal tissue. The TUNEL-positive signal and levels of pro-apoptotic proteins, Bax, cleaved caspase-3, and caspase-8, were elevated in the kidneys of Li+-treated mice. We observed a significantly higher abundance of CD93, CCL21, and fractalkine, accumulation of F4.80+ macrophages with reduced M1/M2 polarization ratio and decreased CD4+ levels in the renal tissue of Li+-treated mice when compared to controls. Therefore, after 28days of treatment, Li+-induced insult to the kidney manifests in facilitated apoptotic cell death without an evident pro-inflammatory response.

Hinokiflavone exerts dual regulation on apoptosis and pyroptosis via the SIX4/Stat3/Akt pathway to alleviate APAP-induced liver injury

Hinokiflavone (HF), classified as a flavonoid, is a main bioactive compound in Platycladus orientalis and Selaginella. HF exhibits activities including anti-HIV, anti-inflammatory, antiviral, antioxidant and anti-tumor effects. The study aimed to explore the function and the mechanisms of HF on acetaminophen (APAP)-induced acute liver injury. Results indicated that HF treatment mitigated the impact of APAP on viability and restored levels of MDA, GSH and SOD on HepG2 cells. The accumulation of reactive oxygen species (ROS) mitochondrial membrane potential (MMP) in HepG2 cells stimulated by APAP were also blocked by HF. HF reduced the levels of pro-apoptotic and pro-pyroptotic proteins. Flow cytometry analysis and fluorescence staining results were consistent with western blot analysis. Following HF treatment in the APAP-induced cell model, there was observed an augmentation in the phosphorylation of Stat3 and an increase in the expression of SIX4. However, not only silenced the SIX4 protein in HepG2 cells by siRNA, but also adding the Stat3 inhibitor (Stattic), attenuated the anti-apoptotic and anti-pyroptotic effects of HF significantly. Furthermore, HF alleviated liver damage in C57BL/6 mice model. Overall, our study demonstrated that HF mitigates apoptosis and pyroptosis induced by APAP in drug-induced liver injury (DILI) through the SIX4/Akt/Stat3 pathway in vivo and in vitro. HF may have promising potential for for the treatment of DILI.

Ultrasound-stimulated microbubbles enhances radiosensitivity in cervical cancer

Background Ultrasound-stimulated microbubble (USMB) therapy has proven efficacy of targeting tumor vasculature and enhancing the effect of radiation in tumor xenografts. In this investigation, we studied whether this treatment enhances the sensitivity of cervical cancer to radiation. Methods Human cervical cancer (ME-180 and SiHa) cells were treated with USMB or exposed to radiation (0, 2, 4, 6 and 8 Gy) or radiation (8 Gy) in combination with USMB. Clone formation assay and CCK-8 assay were used to analyze the proliferation capacity of cells. Apoptosis and DNA double-strand breaks were detected using flow cytometry and immunofluorescence staining of gamma-H2AX (γ-H2AX), respectively. Matrigel tubule formation was performed to evaluate the angiogenesis of human umbilical vein endothelial cells. In xenograft model of SiHa cells, tumor tissue expression of CD31 was detected by immunohistochemistry. Results USMB and radiation synergistically restrained the growth of ME-180 and SiHa cells. USMB promoted radiation-induced apoptosis by enhancing the levels of proapoptotic proteins. Furthermore, USMB enhanced radiation-induced γ-H2AX foci to induce DNA double-strand breaks in cervical cancer cells. USMB in combination with radiation reduced the angiogenic capacity of endothelial cells in vitro. Moreover, USMB strengthened the inhibitory effect of radiation on tumor growth and angiogenesis in xenograft models. Conclusion In conclusion, USMB exposure effectively enhanced the destructive effect of radiation on cervical cancer, suggesting that USMB might be a promising sensitizer of radiotherapy to treat cervical cancer.

Oocyte-specific deletion of eukaryotic translation initiation factor 5 causes apoptosis of mouse oocytes within the early-growing follicles by mitochondrial fission defect-reactive oxygen species-DNA damage.

Mutations in several translation initiation factors are closely associated with premature ovarian insufficiency (POI), but the underlying pathogenesis remains largely unknown. We generated eukaryotic translation initiation factor 5 (Eif5) conditional knockout mice aiming to investigate the function of eIF5 during oocyte growth and follicle development. Here, we demonstrated that Eif5 deletion in mouse primordial and growing oocytes both resulted in the apoptosis of oocytes within the early-growing follicles. Further studies revealed that Eif5 deletion in oocytes downregulated the levels of mitochondrial fission-related proteins (p-DRP1, FIS1, MFF and MTFR) and upregulated the levels of the integrated stress response-related proteins (AARS1, SHMT2 and SLC7A1) and genes (Atf4, Ddit3 and Fgf21). Consistent with this, Eif5 deletion in oocytes resulted in mitochondrial dysfunction characterized by elongated form, aggregated distribution beneath the oocyte membrane, decreased adenosine triphosphate content and mtDNA copy numbers, and excessive accumulation of reactive oxygen species (ROS) and mitochondrial superoxide. Meanwhile, Eif5 deletion in oocytes led to a significant increase in the levels of DNAdamageresponse proteins (γH2AX, p-CHK2 and p-p53) and proapoptotic proteins (PUMA and BAX), as well as a significant decrease in the levels of anti-apoptotic protein BCL-xL. These findings indicate that Eif5 deletion in mouse oocytes results in the apoptosis of oocytes within the early-growing follicles via mitochondrial fission defects, excessive ROS accumulation and DNA damage. This study provides new insights into pathogenesis, genetic diagnosis and potential therapeutic targets for POI. Eif5 deletion in oocytes leads to arrest in oocyte growth and follicle development. Eif5 deletion in oocytes impairs the translation of mitochondrial fission-related proteins, followed by mitochondrial dysfunction. Depletion of Eif5 causes oocyte apoptosis via ROS accumulation and DNA damage response pathway.

Premeiotic deletion of Eif2s2 causes oocyte arrest at the early diplotene stage and apoptosis in mice.

Eukaryotic translation initiation factor 2 subunit 2 (EIF2S2), a subunit of the heterotrimeric G protein EIF2, is involved in the initiation of translation. Our findings demonstrate that the depletion of Eif2s2 in premeiotic germ cells causes oocyte arrest at the pachytene and early diplotene stages at 1 day postpartum (dpp) and 5 dpp, respectively, and eventually leads to oocyte apoptosis and failure of primordial follicle formation. Further studies reveal that Eif2s2 deletion downregulates homologous recombination-related and mitochondrial fission-related protein levels, and upregulates the integrated stress response-related proteins and mRNA levels. Consistently, Eif2s2 deletion significantly decreases the expression of dictyate genes and compromises mitochondrial function, characterized by elongated shapes, decreased ATP levels and mtDNA copy number, along with an excessive accumulation of reactive oxygen species (ROS) and mitochondrial superoxide. Furthermore, DNA damage response and proapoptotic protein levels increase, while anti-apoptotic protein levels decrease in Eif2s2-deleted mice. An increase in oocytes with positive cleaved-Caspase-3 and TUNEL signals, alongside reduced Lamin B1 intensity, further indicates oocyte apoptosis. Collectively, Eif2s2 deletion in premeiotic germ cells causes oocyte meiotic arrest at the early diplotene stage by impairing homologous recombination, and eventually leads to oocyte apoptosis mainly through the downregulation of mitochondrial fission-related proteins, ROS accumulation and subsequent DNA damage.

The effects of Ganoderma leucocontextum triterpenoids treatment on the D-galactose and aluminum chloride-induced Alzheimer-like pathology in mouse brain

Ethnopharmacology relevanceGanoderma leucocontextum T.H. Li, W. Q. Deng M. Wang & H.P.Hu. is a highland herbal medicine that has been shown to nourish the nervesand prolong life. Nevertheless, there is no evidence to indicate that Ganoderma leucocontextum triterpenoids (GLTs) reduce the damage triggered by Alzheimer's disease (AD). Aim of the studyThe aim of this investigation was to ascertain the protective effects of GLTs on AD mice models and cells, as well as to look into potential pathways. Materials and methodsIn this study, the phytochemical characterization of GLTs was performed by High Performance Liquid Chromatography (HPLC) and Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). The AD mouse model was induced by injecting intraperitoneally with D-galactose (120 mg/kg) and administering orally with aluminum chloride (20 mg/kg) daily for 28 days. After that, donepezil (5 mg/kg) and GLTs (0.4, 0.8, and 1.6 g/kg) were administered orally for 35 days. During the treatment period, aluminum chloride (20 mg/kg) and D-galactose (120 mg/kg) were continuously administered. And the behavior of the animals and the molecular changes of the hippocampus were determined after the whole experimental procedure. Furthermore, BV-2 cells were employed to validate GLTs' anti-neuroinflammatory properties. ResultsThe total triterpenoids content was 443.12 ± 0.21 g/kg and was inferred to contain 19 classes of substances such as organic acids, amino acids, vitamins, flavonoids, and other chemicals in GLTs. Treatment of D-galactose/aluminum chloride-induced mouse with GLTs can ameliorate AD symptoms, counteract cognitive decline, improve Aβ1-42 deposition, reduce the expression level of pro-apoptotic proteins, and attenuate the activation of hippocampal microglia and astrocytes. GLTs significantly increased the expression of antioxidant enzymes and significantly reduced the expression of inflammatory factors. GLTs inhibits nuclear factor kappa B (NF-κB) nuclear translocation and preserves myd88/traf6-mediated mitogen-activated protein kinase (MAPK) phosphorylation. Furthermore, GLTs (2 and 5 mg/mL) inhibited the generation of nitric oxide and protected lipopolysaccharide (1 mg/L)-induced neuroinflammation in BV-2 cells. ConclusionsTaken together, Ganoderma leucocontextum triterpenoids can improve cognitive functions, including learning and memory, by reducing neuroinflammation and oxidative stress, preventing apoptosis, and controlling amyloid genesis.

Protein phosphatase SCP4 regulates cartilage development and endochondral osteogenesis via FoxO3a dephosphorylation.

The regulatory mechanisms involved in embryonic development are complex and yet remain unclear. SCP4 represents a novel nucleus-resident phosphatase identified in our previous study. The primary aim of this study was to elucidate the function of SCP4 in the progress of cartilage development and endochondral osteogenesis. SCP4-/- and SCP4Col2ER mice were constructed to assess differences in bone formation using whole skeleton staining. ABH/OG staining was used to compare chondrocyte differentiation and cartilage development. Relevant biological functions were analysed using RNA-sequencing and GO enrichment, further validated by immunohistochemical staining, Co-IP and Western Blot. Global SCP4 knockout led to abnormal embryonic development in SCP4-/- mice, along with delayed endochondral osteogenesis. In parallel, chondrocyte-specific removal of SCP4 yielded more severe embryonic deformities in SCP4Col2ER mice, including limb shortening, reduced chondrocyte number in the growth plate, disorganisation and cell enlargement. Moreover, RNA-sequencing analysis showed an association between SCP4 and chondrocyte apoptosis. Notably, Tunnel-positive cells were indeed increased in the growth plates of SCP4Col2ER mice. The deficiency of SCP4 up-regulated the expression levels of pro-apoptotic proteins both in vivo and in vitro. Additionally, phosphorylation of FoxO3a (pFoxO3a), a substrate of SCP4, was heightened in chondrocytes of SCP4Col2ER mice growth plate, and the direct interaction between SCP4 and pFoxO3a was further validated in chondrocytes. Our findings underscore the critical role of SCP4 in regulating cartilage development and endochondral osteogenesis during embryonic development partially via inhibition of chondrocytes apoptosis regulated by FoxO3a dephosphorylation.

Kuwanon C inhibits proliferation and induction of apoptosis via the intrinsic pathway in MDA-MB231 and T47D breast cancer cells

Breast cancer ranks as the most prevalent malignancy, presenting persistent therapeutic challenges encompassing issues such as drug resistance, recurrent occurrences, and metastatic progression. Therefore, there is a need for targeted drugs that are less toxic and more effective against breast cancer. Kuwanon C, an isoamylated flavonoid derived from mulberry resources, has shown promise as a potential candidate due to its strong cytotoxicity against cancer cells. The present study focused on investigating the anticancer activity of kuwanon C in two human breast cancer cell lines, MDA-MB231 and T47D cells. MTS assay results indicated a decrease in cell proliferation with increasing concentrations of kuwanon C. Furthermore, kuwanon C upregulated the expression levels of the cyclin-dependent kinase inhibitor p21 and effectively inhibited cell DNA replication and induced DNA damage. Flow cytometry confirmed that kuwanon C induced cell apoptosis and upregulated the expression levels of pro-apoptotic proteins (Bax and c-caspase3). Additionally, it stimulated the production of reactive oxygen species (ROS) in the cells. Transmission electron microscopy and Fluo-4 AM-calcium ion staining experiments provided insights into the endoplasmic reticulum (ER), revealing that kuwanon C induced ER stress. Kuwanon C upregulated the expression levels of unfolded protein response-related proteins (ATF4, GADD34, HSPA5, and DDIT3). Overall, the present findings suggested that kuwanon C exerts a potent inhibitory effect on breast cancer cell proliferation through modulating of the p21, induction of mitochondrial-mediated apoptosis, activation of ER stress and induction of DNA damage. These results position kuwanon C as a potential targeted therapeutic agent for breast cancer.

Capsaicin reverses cisplatin resistance in tongue squamous cell carcinoma by inhibiting the Warburg effect and facilitating mitochondrial-dependent apoptosis via the AMPK/AKT/mTOR axis.

Cisplatin is commonly used for the chemotherapy of tongue squamous cell carcinoma (TSCC); however, adverse side effects and drug resistance impact its therapeutic efficacy. Capsaicin is an active ingredient in chili peppers that exerts antitumor effects, whether it exerts antitumor effects on cisplatin-resistant cells remains unknown. Therefore, in this study, we investigated the effect of capsaicin on cisplatin resistance in TSCC cells and explored the underlying mechanisms. A cisplatin-resistant TSCC cell line was established by treated with increasing cisplatin concentrations. Combined treatment with cisplatin and capsaicin decreased the glucose consumption and lactate dehydrogenase activity and increased the adenosine triphosphate production both in vitro and in vivo, suggesting the inhibition of the Warburg effect. Moreover, this combined treatment induced cell apoptosis and significantly upregulated the levels of proapoptotic proteins, such as Bax, cleaved caspase-3, -7, and -9, and apoptosis-inducing factor. In contrast, levels of the antiapoptotic protein, Bcl-2, were downregulated. Additionally, LKB1 and AMPK activities were stimulated, whereas those of AKT and mTOR were suppressed. Notably, AMPK knockdown abolished the inhibitory effects of capsaicin and cisplatin on the AKT/mTOR signaling pathway and Warburg effect. Overall, combined treatment with capsaicin and cisplatin reversed cisplatin resistance by inhibiting the Warburg effect and facilitating mitochondrial-dependent apoptosis via the AMPK/AKT/mTOR axis. Our findings suggest combination therapy with capsaicin and cisplatin as a potentially novel strategy and highlight capsaicin as a promising adjuvant drug for TSCC treatment.

Knocking-down long non-coding RNA LINC01094 prohibits chondrocyte apoptosis via regulating microRNA-577/metal-regulatory transcription factor 1 axis.

The abnormal function and survival of chondrocytes result in articular cartilage failure, which may accelerate the onset and development of osteoarthritis (OA). This study is aimed to investigate the role of LINC01094 in chondrocyte apoptosis. The viability and apoptosis of lipopolysaccharide (LPS)-induced chondrocytes were evaluated through CCK-8 assay and flow cytometry analysis, respectively. The expression levels of LINC01094, miR-577 and MTF1 were detected by qRT-PCR. Dual luciferase reporter tests were implemented for the verification of targeted relationships among them. Western blotting was employed to measure the levels of pro-apoptotic proteins (Caspase3 and Caspase9). The viability of LPS-induced chondrocytes was overtly promoted by loss of LINC01094 or miR-577 upregulation, but could be repressed via MTF1 overexpression. The opposite results were observed in apoptosis rate and the levels of Caspase3 and Caspase9. LINC01094 directly bound to miR-577, while MTF1 was verified to be modulated by miR-577. Both LINC01094 and MTF1 were at high levels, whereas miR-577 was at low level in OA synovial fluid and LPS-induced chondrocytes. Furthermore, the highly expressed miR-577 abolished the influences of MTF1 overexpression on LPS-induced chondrocytes. Silencing of LINC01094 represses the apoptosis of chondrocytes through upregulating miR-577 expression and downregulating MTF1 levels, providing a preliminary insight for the treatment of OA in the future.

Anticancer Effects of Mitoquinone via Cell Cycle Arrest and Apoptosis in Canine Mammary Gland Tumor Cells.

Treating female canine mammary gland tumors is crucial owing to their propensity for rapid progression and metastasis, significantly impacting the overall health and well-being of dogs. Mitoquinone (MitoQ), an antioxidant, has shown promise in inhibiting the migration, invasion, and clonogenicity of human breast cancer cells. Thus, we investigated MitoQ's potential anticancer properties against canine mammary gland tumor cells, CMT-U27 and CF41.Mg. MitoQ markedly suppressed the proliferation and migration of both CMT-U27 and CF41.Mg cells and induced apoptotic cell death in a dose-dependent manner. Furthermore, treatment with MitoQ led to increased levels of pro-apoptotic proteins, including cleaved-caspase3, BAX, and phospho-p53. Cell cycle analysis revealed that MitoQ hindered cell progression in the G1 and S phases in CMT-U27 and CF41.Mg cells. These findings were supported using western blot analysis, demonstrating elevated levels of cleaved caspase-3, a hallmark of apoptosis, and decreased expression of cyclin-dependent kinase (CDK) 2 and cyclin D4, pivotal regulators of the cell cycle. In conclusion, MitoQ exhibits in vitro antitumor effects by inducing apoptosis and arresting the cell cycle in canine mammary gland tumors, suggesting its potential as a preventive or therapeutic agent against canine mammary cancer.

Abstract 4752: Enhancer of zeste homolog 2 inhibitors overcome glucocorticoid resistance in acute lymphoblastic leukemia by augmenting pro-apoptotic signaling

Abstract Introduction Relapsed acute lymphoblastic leukemia (ALL) portends a poor prognosis. Glucocorticoids (GCs) are a central component of a multi-agent regimen to treat ALL. GCs mediate ligand-dependent global transcriptional changes activating feedback loop that increases GC receptor (GR) expression and pro-apoptotic signaling. GC resistance is a common mechanism in relapsed/refractory ALL. Altered function of Enhancer of Zeste Homolog 2 (EZH2), a histone methyl transferase (HMT), including increased expression and activating mutations have been reported in ALL. Previously, EZH2 inhibitors have been shown to increase GC efficacy in non-ALL B-cell lymphoid malignancies including non-Hodgkin lymphoma. Furthermore, EZH2 inhibitors reversed GC resistance and increased efficacy of GCs in an ALL subtype with an activating point mutation in an HMT called nuclear set domain 2. Overcoming GC resistance by novel therapeutic strategies may help improve outcomes in relapsed/refractory ALL. Hypothesis EZH2 inhibitors may enhance GC efficacy by augmenting downstream effects of GCs. Methods We performed in-vitro studies of EZH2 inhibitors, EPZ-6438 and CPI-1205, at graded doses in GC resistance human-derived B-cell (SUPB15) and T-cell (SUPT1, KOPTK1, PEER) ALL cell lines followed by graded doses of dexamethasone (dex). Cell viability was performed using CellTiter-Glo assay. Induction of apoptosis was measured with Annexin V flow cytometry. Pro-apoptotic BIM mRNA and protein levels were measured using real-time PCR and immunoblot. Global H3K27me3 protein levels were assessed using immunoblot. Results GC resistant B-cell ALL and T-cell ALL treated with EZH2 inhibitors for 3-7 days followed by the addition of dex for 48-72 hours led to decreased cell viability and increased apoptosis of the ALL cells compared to cells treated with vehicle (DMSO) and dex alone. EZH2 inhibitors on their own did not cause apoptosis. SynergyFinder revealed Bliss synergy scores between 23- 31 in B-cell ALL and T-cell ALL cell lines with greater than 10 considered a synergistic drug interaction. Immunoblotting of cells treated with EZH2 inhibitors alone showed an increase in pro-apoptotic protein, BIM. BIM level was further enhanced when dex was added in combination with EZH2 inhibitors compared to vehicle and dex alone suggesting that EZH2 inhibitors were augmenting BIM expression. Further assessment of the mechanism of how EZH2 inhibitors lead to improved GC efficacy will be performed by integrating transcriptomic and epigenomic profiling in the presence and absence of EZH2 inhibitors. Furthermore, in-vivo testing of EZH2 inhibitors in patient derived xenografts will be performed. Conclusion EZH2 inhibitors can overcome GC resistance in ALL posing as a potential novel therapeutic agent to treat relapsed/refractory ALL. Citation Format: Mansi Dalal, Joanna Yi, Jianping Li, Amin Shobh, Daphne DupereRicher, Richard Bennett, Jonathan Licht. Enhancer of zeste homolog 2 inhibitors overcome glucocorticoid resistance in acute lymphoblastic leukemia by augmenting pro-apoptotic signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4752.