Apoptosis Research Articles

Therapeutic potential of mesenchymal stem cells and stem cell-derived extracellular vesicles in tuberculosis of various localizations: A review

Experimental and clinical studies using cell therapy are very popular. Mesenchymal stem cells (MSCs) and stem cell-derived extracellular vesicles (EV) are used as one of the components of therapy in these researches. The action of MSCs is mediated by the release of EV which play a direct role in the implementation of several important biological processes: angiogenesis, proliferation, modulation of the inflammatory process and immune response, inhibition of cellular apoptosis, etc. These properties of MSCs and stem cell-derived EV are of interest in the treatment of tuberculosis infection, because an integral part of the pathogenesis of tuberculosis is the creation of specific granulomas and the formation of fibrosis.

The PANoptosis-related hippocampal molecular subtypes and key biomarkers in Alzheimer’s disease patients

Alzheimer’s Disease (AD) is a neurodegenerative disorder, and various molecules associated with PANoptosis are involved in neuroinflammation and neurodegenerative diseases. This work aims to identify key genes, and characterize PANoptosis-related molecular subtypes in AD. Moreover, we establish a scoring system for distinguishing PANoptosis molecular subtypes and constructing diagnostic models for AD differentiation. A total of 5 hippocampal datasets were obtained from the Gene Expression Omnibus (GEO) database. In total, 1324 protein-encoding genes associated with PANoptosis (1313 apoptosis genes, 11 necroptosis genes, and 31 pyroptosis genes) were extracted from the GeneCards database. The Limma package was used to identify differentially expressed genes. Weighted Gene Co-Expression Network Analysis (WGCNA) was conducted to identify gene modules significantly associated with AD. The ConsensusClusterPlus algorithm was used to identify AD subtypes. Gene Set Variation Analysis (GSVA) was used to assess functional and pathway differences among the subtypes. The Boruta, Least Absolute Shrinkage and Selection Operator (LASSO), Random Forest (RF), and Support Vector Machine Recursive Feature Elimination (SVM-RFE) algorithms were used to select the three PANoptosis-related Key AD genes (PKADg). A scoring model was constructed based on the Boruta algorithm. PANoptosis diagnostic models were developed using the RF, SVM-RFE, and Logistic Regression (LR) algorithms. The ROC curves were used to assess the model performance. A total of 48 important genes were identified by intersecting 725 differentially expressed genes and 2127 highly correlated module genes from WGCNA with 1324 protein-encoding genes related to PANoptosis. Machine learning algorithms identified 3 key AD genes related to PANoptosis, including ANGPT1, STEAP3, and TNFRSF11B. These genes had strong discriminatory capacities among samples, with Receiver Operating Characteristic Curve (ROC) analysis indicating Area Under the Curve (AUC) values of 0.839, 0.8, and 0.868, respectively. Using the 48 important genes, the ConsensusClusterPlus algorithm identified 2 PANoptosis subtypes among AD patients, i.e., apoptosis subtype and mild subtype. Apoptosis subtype patients displayed evident cellular apoptosis and severe functionality damage in the hippocampal tissue. Meanwhile, mild subtype patients showed milder functionality damage. These two subtypes had significant differences in apoptosis and necroptosis; however, there was no apparent variation in pyroptosis functionality. The scoring model achieved an AUC of 100% for sample differentiation. The RF PANoptosis diagnostic model demonstrated an AUC of 100% in the training set and 85.85% in the validation set for distinguishing AD. This study identified two PANoptosis-related hippocampal molecular subtypes of AD, identified key genes, and established machine learning models for subtype differentiation and discrimination of AD. We found that in the context of AD, PANoptosis may influence disease progression through the modulation of apoptosis and necrotic apoptosis.

α-Mangostin-phytosomes as a plausible nano-vesicular approach for enhancing cytotoxic activity on SKOV-3 ovarian cancer cells

Backgroundα-Mangostin is a major xanthone in Garcinia mangostana L. (Clusiaceae) pericarps. It has promising anti-proliferative potential in different cancer cells; however, it has poor oral bioavailability. Phytosomes are used as a novel nano-based drug delivery system. The aim of this research was to enhance the anti-proliferative potency of α-mangostin by formulating it as α-mangostin-phytosome (α-M-PTMs) and assessing its impact on SKOV-3 ovarian cancer cells in comparison to pure α-mangostin.ResultsThe size and entrapment efficiency of the proposed formulation were optimized using Box–Behnken statistics. The optimized formula was characterized using transmission electron microscope. The binding of α-mangostin to phospholipids was confirmed using Fourier-transform infrared (FTIR) spectroscopy. The optimized α-mangostin-phytosomes formula exhibited enhanced anti-proliferative activity with reference to raw α-mangostin. This was further substantiated by assessing the cell cycle phases that indicated an accumulation of SKOV-3 cells in the sub-G1 phase. Annexin-V staining revealed enhanced apoptotic activity in α-mangostin-phytosome-treated cells. This was associated with upregulation of CASP3 (Caspase-3), BAX (BCL2 Associated X, Apoptosis Regulator) and TP53 as well as down-regulation of BCL2 mRNA (B-Cell Leukemia/Lymphoma 2). Moreover, our data indicated enhanced ROS (Reactive oxygen species) production, cytochrome-C release, and disturbed MMP (mitochondrial membrane potential).ConclusionEncapsulation of α-mangostin in a phytosome nano-formula enhances its anti-proliferative effects in SKOV-3 cells via, at least in part, inducing mitochondrial apoptotic cell death.

ONCOLYTIC ACTIVITY OF HUMAN RESPIRATORY SYNCYTIAL VIRUS.

Oncolytic viruses (OVs) are emerging as novel tools in cancer therapy. Oncolytic virotherapy offers an attractive therapeutic combination of tumor-specific killing and immune co-stimulation, therefore amplifying the host immune response against tumors. Moreover, OVs can be engineered for the expression of different immunostimulatory molecules to optimize and enhance the efficacy of oncolytic virotherapy. The effectiveness of OVs has been demonstrated in many preclinical studies for different types of cancers to achieve the aim of personalized cancer therapy. Human respiratory syncytial virus (RSV), an RNA virus of the Pneumoviridae family causes severe lower respiratory tract infections in infants and immunocompromised individuals. Interestingly, the oncolytic activity of RSV demonstrated in human prostate, hepatocellular, and dermal cancer cells is mostly mediated via apoptotic cell death associated with the impaired NF-κB activation or with the defect of the IFNα/β-induced STAT-1 activation. At the same time, the studies on cervical cancer revealed that RSV infection resulted in autophagy activation and apoptosis through the ROS-BAX and TNF- α-mediated pathways. The rational combinations of OVs, including RSV, with other approaches may benefit patients whose response to conventional therapies is limited. Here, we discuss the oncolytic activity of RSV and its potential use against different types of cancer.

Synergistic effect of Hypoxic Conditioning and Cell-Tethering Colloidal Gels enhanced Productivity of MSC Paracrine Factors and Accelerated Vessel Regeneration.

Microporous hydrogels have been widely used for delivering therapeutic cells. However, several critical issues, such as the lack of control over the harsh environment they are subjected to under pathological conditions and rapid egression of cells from the hydrogels, have produced limited therapeutic outcomes. To address these critical challenges, cell-tethering and hypoxic conditioning colloidal hydrogels containing mesenchymal stem cells (MSCs) are introduced to increase the productivity of paracrine factors locally and in a long-term manner. Cell-tethering colloidal hydrogels that are composed of tyramine-conjugated gelatin prevent cells from egressing through on-cell oxidative phenolic crosslinks while providing mechanical stimulation and interconnected microporous networks to allow for host-implant interactions. Oxygenating microparticlesencapsulated in tyramine-conjugated colloidal microgels continuously generated oxygen for 2 weeks with rapid diffusion, resulting in maintaining a mild hypoxic condition while MSCs consumed oxygen under severe hypoxia. Synergistically, local retention of MSCs within the mild hypoxic-conditioned and mechanically robust colloidal hydrogels significantly increased the secretion of various angiogenic cytokines and chemokines. The oxygenating colloidal hydrogels induced anti-inflammatory responses, reduced cellular apoptosis, and promoted numerous large blood vessels in vivo. Finally, mice injected with the MSC-tethered oxygenating colloidal hydrogels significantly improved blood flow restoration and muscle regeneration in a hindlimb ischemia (HLI) model.

Effect of crude ethanolic seed extract from Mucuna pruriens on proliferation, apoptosis, and cell cycle arrest in gastric adenocarcinoma (AGS) cells

Abstract Background Gastric cancer is a prevalent form of malignancy among many common carcinoma cases globally. This study was designed to assess the anticancer potential of the crude ethanolic seed extract from Mucuna pruriens against the gastric cancer cell line (AGS). Various assays were employed to assess the anticancer properties, including examinations of cell viability, nuclear morphology, apoptosis using AO/EB staining, changes in mitochondrial membrane potential, lactate dehydrogenase activity, DNA fragmentation, and cell cycle arrest. Results The crude extract exhibited significant anticancer activity against the human gastric cancer cell line (AGS), as determined by the MTT assay, with an inhibition concentration (IC50) of 600 µg/mL at 24 h. Distinct cellular and nuclear morphological changes were observed with different concentrations of crude ethanolic seed extract. The LDH release assay reveals cell death in AGS cells, as evidenced by a significant increase in the release of LDH enzyme. DNA fragmentation analysis and flow cytometry results indicate that the extract induces chromatin condensation, apoptotic cell death, and cell cycle arrest at the G0/G1 phase in the AGS cancer cell line. These results highlight the potential therapeutic advantages of Mucuna pruriens seed extract against gastric cancer cells. Conclusion This study could pave the way for identifying diverse natural bioactive compounds sourced from Mucuna pruriens seed, leading to the development of novel drug with potential anticancer properties.

Exploring Angiotensin II and Oxidative Stress in Radiation-Induced Cataract Formation: Potential for Therapeutic Intervention

Radiation-induced cataracts (RICs) represent a significant public health challenge, particularly impacting individuals exposed to ionizing radiation (IR) through medical treatments, occupational settings, and environmental factors. Effective therapeutic strategies require a deep understanding of the mechanisms underlying RIC formation (RICF). This study investigates the roles of angiotensin II (Ang II) and oxidative stress in RIC development, with a focus on their combined effects on lens transparency and cellular function. Key mechanisms include the generation of reactive oxygen species (ROS) and oxidative damage to lens proteins and lipids, as well as the impact of Ang II on inflammatory responses and cellular apoptosis. While the generation of ROS from water radiolysis is well established, the impact of Ang II on RICs is less understood. Ang II intensifies oxidative stress by activating type 1 receptors (AT1Rs) on lens epithelial cells, resulting in increased ROS production and inflammatory responses. This oxidative damage leads to protein aggregation, lipid peroxidation, and apoptosis, ultimately compromising lens transparency and contributing to cataract formation. Recent studies highlight Ang II’s dual role in promoting both oxidative stress and inflammation, which accelerates cataract development. RICs pose a substantial public health concern due to their widespread prevalence and impact on quality of life. Targeting Ang II signaling and oxidative stress simultaneously could represent a promising therapeutic approach. Continued research is necessary to validate these strategies and explore their efficacy in preventing or reversing RIC development.

Unraveling the role of long non-coding RNAs in chronic heat stress-induced muscle injury in broilers

BackgroundChronic heat stress (CHS) is a detrimental environmental stressor with a negative impact on the meat quality of broilers. However, the underlying mechanisms are not fully understood. This study investigates the effects of CHS on long non-coding RNA (lncRNA) expression and muscle injury in broilers, with a focus on its implications for meat quality.ResultsThe results showed that CHS diminished breast muscle yield, elevated abdominal fat deposition, induced cellular apoptosis (P < 0.05), and caused myofibrosis. Transcriptomic analysis revealed 151 differentially expressed (DE) lncRNAs when comparing the normal control (NC) and HS groups, 214 DE lncRNAs when comparing the HS and PF groups, and 79 DE lncRNAs when comparing the NC and pair-fed (PF) groups. After eliminating the confounding effect of feed intake, 68 lncRNAs were identified, primarily associated with cellular growth and death, signal transduction, and metabolic regulation. Notably, the apoptosis-related pathway P53, lysosomes, and the fibrosis-related gene TGF-β2 were significantly upregulated by lncRNAs.ConclusionsThese findings indicate that chronic heat stress induces cellular apoptosis and muscle injury through lncRNA, leading to connective tissue accumulation, which likely contributes to reduced breast muscle yield and meat quality in broilers.

Low-power red laser and blue LED modulate telomere maintenance and length in human breast cancer cells.

Cancer cells have the ability to undergo an unlimited number of cell divisions, which gives them immortality. Thus, the cancer cell can extend the length of its telomeres, allowing these cells to divide unlimitedly and avoid entering the state of senescence or cellular apoptosis. One of the main effects of photobiomodulation (PBM) is the increase in the production of adenosine triphosphate (ATP) and free radicals, mainly reactive oxygen species (ROS). Existent data indicates that high levels of ROS can cause shortening and dysfunctional telomeres. Therefore, a better understanding of the effects induced by PBM on cancer cell telomere maintenance is needed. This work aimed to evaluate the effects of low-power red laser (658nm) and blue LED (470nm) on the TRF1 and TRF2 mRNA levels and telomere length in human breast cancer cells. MCF-7 and MDA-MB-231 cells were irradiated with a low-power red laser (69J cm-2, 0.77W/cm-2) and blue LED (482J cm-2, 5.35W/cm-2), alone or in combination, and the relative mRNA levels of the genes and telomere length were assessed by quantitative reverse transcription polymerase chain reaction. The results suggested that exposure to certain red laser and blue LED fluences decreased the TRF1 and TRF2 mRNA levels in both human breast cancer cells. Telomere length was increased in MCF-7 cells after exposure to red laser and blue LED. However, telomere length in MDA-MB-231 was shortened after exposure to red laser and blue LED at fluences evaluated. Our research suggests that photobiomodulation induced by red laser and low-power blue LED could alter telomere maintenance and length.

Application of XBP1s Decoy Oligodeoxynucleotide Attenuates Cancerous Phenotype in Huh-7 Hepatocellular Carcinoma Cells.

The spliced form of X-box binding protein 1 (XBP1s) is a key transcription factor in the unfolded protein response (UPR), an adaptive mechanism for cell survival. Many studies demonstrated the induced expression of XBP1s in various cancers, including hepatocellular carcinoma (HCC). Such upregulated expression is linked to an enhancement of cell proliferation, migration, and improvement of the survival rate. In this study, we aimed to assess the therapeutic potential of targeting XBP1s, by specific decoy oligodeoxynucleotide (ODN) and evaluated the cancerous phenotypes in Huh-7 cells. In this experimental study, we transfected Huh-7 cells with XBP1s decoy oligonucleotide (ODN). Subsequently, we assess some cellular features, including viability, migration capacity, proliferation potential, and apoptosis. Therefore, various techniques included wound healing test, BrdU, and annexin/PI assays. Additionally, the colony formation capacity was evaluated. The mRNA expression levels of BAX, BCL-2, c-MYC, CCND1, MMP-9, CDH1, and CD133 were quantified by the reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Transfection of Huh-7 cells by XBP1s decoy ODN led to significant down-regulation of c-Myc, CCND1, MMP-9, BCL-2 and CD133 and up-regulation of CDH1 and BAX transcriptional expressions in comparison with the vehicle group. Our results also demonstrated that transfection of XBP1s-decoy reduced HCC cell viability, proliferation, migration capacity as well as colonization ability in comparison with the vehicle group. These findings proposed the potential application of XBP1s-decoy ODN to reduce cancerous phenotypes such as cell proliferation, cell migration and apoptosis induction in the Huh-7 cell line. More experiments on other cell lines and primary cells could validate our results.

Levofloxacin induces erythrocyte contraction leading to red cell death.

Levofloxacin, a fluoroquinolone, is an extensively used antibiotic effective against both positively and negatively staining bacteria. It works by inhibiting bacterial topoisomerase type II and topoisomerase type IV, resulting in impaired DNA synthesis and bacterial cell death. Eryptosis is another term for apoptotic cell death of erythrocyte marked by cell shrinkage, phosphatidylserine (PS) flipping, and membrane blebbing. The intent of the present research was to look at the eryptotic effect of levofloxacin by exposing erythrocytes to therapeutical doses (7, 14 µM) of levofloxacin for 48 hours. Cell size evaluation, PS subjection to outside, and calcium channel inhibition were carried out to investigate eryptosis. Oxidative stress generated by levofloxacin was measured as a putative mechanism of eryptosis using glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase activities. Similarly, hemolysis measurements demonstrated levofloxacin's cytotoxic effect. Our findings showed that therapeutic doses of levofloxacin can cause a considerable decline in antioxidant enzymes activities, as well as induce cell shrinkage, PS externalization, and hemolysis in erythrocytes. The role of calcium in triggering erythrocyte shrinkage was also confirmed. In conclusion, our findings showed that the indicated levofloxacin doses caused oxidative stress, which leads to erythrocyte death via eryptosis and hemolysis. These findings emphasize the importance of using levofloxacin with caution and the need for additional research to mitigate these side effects.

Comparison of Survivin Determination by Surface-Enhanced Fluorescence and Raman Spectroscopy on Nanostructured Silver Substrates

Survivin belongs to a family of proteins that promote cellular proliferation and inhibit cellular apoptosis. Its overexpression in various cancer types has led to its recognition as an important marker for cancer diagnosis and treatment. In this work, we compare two approaches for the immunochemical detection of survivin through surface-enhanced fluorescence or Raman spectroscopy using surfaces with nanowires decorated with silver nanoparticles in the form of dendrites or aggregates as immunoassays substrates. In both substrates, a two-step non-competitive immunoassay was developed using a pair of specific monoclonal antibodies, one for detection and the other for capture. The detection antibody was biotinylated and combined with streptavidin labeled with rhodamine for the detection of surface-enhanced fluorescence, while, for the detection via Raman spectroscopy, streptavidin labeled with peroxidase was used and the signal was obtained after the application of 3,3′,5,5′-tetramethylbenzidine (TMB) precipitating substrate. It was found that the substrate with the silver dendrites provided higher fluorescence signal intensity compared to the substrate with the silver aggregates, while the opposite was observed for the Raman signal. Thus, the best substrate was used for each detection method. A detection limit of 12.5 pg/mL was achieved with both detection approaches along with a linear dynamic range up to 500 pg/mL, enabling survivin determination in human serum samples from both healthy and ovarian cancer patients for cancer diagnosis and monitoring purposes.

7193 Hypocalcemia: Pitfalls, Paradoxes, And Conundrums

Abstract Disclosure: K. Dash: None. P. Eswaran: None. K. Maharajan: None. S. Nangia: None. U. Ayyagari: None. 58 year old female with PV bleed was diagnosed as Carcinoma Cervix and recommended radical radiotherapy with 6 weeks of concurrent chemotherapy with Cisplatin and IV Magnesium premedication. Post 6th cycle of chemo, she presented with nausea, perioral and facial tingling, and lower limb cramps of one day duration. Investigations showed Serum Magnesium 0.4 mg/dl (range 1.6–2.5), Calcium 5.9 mg/dl (8.4-10.2), Potassium 3.3 mg/dl (3.5-5.5). She was treated with IV Calcium gluconate and discharged home post correction with serum Calcium 7.9, Magnesium 1.8, PTH 88.7. She was readmitted twice, 5 and 9 days later, with hypocalcemia, given IV Calcium Gluconate, and discharged post correction of serum calcium levels. She presented to Endocrine OP 2 days later, asymptomatic, serum Calcium 5.9, Magnesium 0.6, K 3.8. She was admitted and replacement commenced with IV Magnesium and Calcium. Over the next day her Calcium and Magnesium levels improved. She was stabilized on oral Calcium and Magnesium replacement and discharged. Calcium replacement was weaned over the next 2 weeks with stable serum Calcium levels on continuing oral Magnesium replacement to date. Cisplatin is a commonly used chemotherapeutic agent. It binds to the N7 reactive center on purine residues and causes DNA damage in cancer cells blocking cell division resulting in apoptotic cell death. This interaction with DNA and the formation of covalent adducts with purine DNA bases is the source of the cytotoxic effect of cisplatin. Therapy is associated with side effects including neuro-, nephro-, hepato-, and cardiotoxicity. Electrolyte disturbances including hypomagnesemia, hypocalcemia, hypokalemia, and hyponatremia are recognized in association with cisplatin therapy. The signs and symptoms of dyselectrolytemias may be nonspecific and a high index of suspicion is required to diagnose. Hypomagnesemia is described in up to 78% of patients on cisplatin due to magnesium wasting attributed to reduced magnesium reabsorption in the distal tubule and/or inadequate intestinal magnesium absorption. Magnesium is primarily an intracellular cation and stored in bone. Serum levels are a poor indicator of total body magnesium and serum concentrations &amp;lt;1.8 mg/dl indicate more severe underlying deficit. Hypocalcemia, possibly due to end organ unresponsiveness to PTH, frequently coexists with hypomagnesimia, and can be resistant to treatment unless hypomagnesimia is corrected. While hypomagnesimia stimulates PTH secretion, very low serum concentrations can induce a paradoxical block. Our case illustrates the importance of recognizing and correcting underlying hypomagnesimia to stabilize serum calcium levels. The normal PTH level, despite low serum Calcium, suggests hypomagnesimia impairing parathyroid gland function. Due to the acute presentation, and ongoing IV correction, we were unable to measure urinary magnesium excretion. Presentation: 6/1/2024

7587 The Estrogen Receptors and ARE/Nrf2 are Involved in Protecting Human Dermal Fibroblasts from Damage Caused by Mitochondrial Disfunction

Abstract Disclosure: A. Darawshe: None. A. Trachtenberg: None. Y. Sharoni: None. Skin ageing is influenced by several factors including environmental exposure and hormonal changes. Reactive oxygen species (ROS), which mediate many of the effects of these factors, can be formed by extrinsic factors, such as sun exposure, or can result from mitochondrial dysfunction as occurs during ageing. Several studies have shown the protective role of estrogens on skin health. The aim of the current study was to examine the damage to dermal fibroblasts by mitochondrially generated ROS, and to study the mechanism of the protective effects of estradiol. Rotenone, a complex I inhibitor, was used to cause mitochondrial dysfunction in human dermal fibroblasts and its effects on mitochondrial and cytosolic ROS levels, mitochondrial respiration, cell death, apoptosis, matrix metalloproteinase-1 (MMP1) and pro-collagen secretion were determined as markers of skin damage. Rotenone caused substantial reduction of respiration, followed by increased mitochondrial and cytosolic ROS which resulted in apoptotic cell death, increased MMP1 secretion and decreased collagen secretion. Pretreatment with estradiol recovered more than 50% of the respiratory activity, reduced mitochondrial and cytosolic ROS levels and MMP1 secretion and increased cell number and collagen secretion. These effects can be partially explained by a cooperative effect of estradiol and rotenone on Antioxidant Response Element (ARE/Nrf2) transcriptional activity, which leads to upregulation of antioxidant proteins such as NQO1 and Trxr1. To determine if estrogen receptors (ER) are involved in the protective effects, we used the ER inhibitor, Fulvestrant. This inhibitor, which completely inhibited ER Response Element reporter activity, partially prevented the protective effects of estradiol. The protective effects of estradiol were Similarly reduced by ML385 and Ochratoxin A, that are inhibitors of the ARE/Nrf2 transcription system. Incubating the cells with Fulvestrant and Ochratoxin A, which inhibit both pathways, completely blocked the protective effect of estradiol. These results suggest that the estrogen receptors and the ARE/Nrf2 signaling pathways are involved in the protective effects of estradiol against the damage caused by rotenone-induced mitochondria generated oxidative stress. Presentation: 6/3/2024

8071 Prevention Of Acute Kidney Injury By Reducing Mitochondrial Dysfunction In Diabetic Mice

Abstract Disclosure: M. Kim: None. C. Oh: None. A. Khang: None. J. Jeon: None. I. Lee: None. Background: Acute Kidney Injury (AKI) significantly contributes to the pathogenesis of diabetic kidney disease, often exacerbating chronic kidney disease (CKD) and accelerating the need for dialysis. Mitochondrial dysfunction, induced by an increase in reactive Oxygen Species (ROS) and inflammation, plays a crucial role in AKI. This study investigates the prevention of AKI by reducing mitochondrial dysfunction through pyruvate dehydrogenase kinase (PDK) inhibition in an ischemia-reperfusion (IR)-induced AKI model using streptozotocin (STZ)-induced diabetic mice. Methods: We utilized an IR-induced AKI model in STZ-induced diabetic C57BL6/J mice, subjecting them to IR by clamping both renal pedicles. Mitochondrial function tests, cellular apoptosis, and inflammatory markers were evaluated in NRK-52E cells and mouse primary tubular cells after hypoxia and reoxygenation using a hypoxia workstation. Results: In diabetic mice experiencing AKI following IR injury, there was a significant increase in pyruvate dehydrogenase E1α (PDHE1α) phosphorylation. This correlated with a notable increase in mitochondrial damage - TEM images of mice with IR-induced kidney injury revealed distension, loss of cristae, and fragmentation of the mitochondria. We also observed a decrease in oxygen consumption rate (OCR) accompanied by increased ROS, as well as increased production of inflammatory markers. Remarkably, the pan-PDK inhibitor, sodium dichloroacetate (DCA), mitigated apoptosis, attributable to the reduction of PDHE1α phosphorylation levels as well as normalized mitochondrial morphology and function. DCA treatment lessened oxidative stress and decreased the production of inflammatory markers following IR-induced AKI or hypoxia-reoxygenation injury. Conclusion: Restoration of mitochondrial function by DCA effectively alleviated renal injury by decreasing ROS production and inflammation, highlighting its critical role in IR-mediated damage. These results suggest another potential target for renal protection during AKI; therefore, the prevention of acute kidney injury through the inhibition of PDK could be a promising therapeutic approach for treating Diabetic Kidney Disease (DKD). Presentation: 6/1/2024

7888 Mitotane Induces Different Modes Of Cell Death In Treatment Resistant And Sensitive Models Of Adrenocortical Carcinoma

Abstract Disclosure: S. Feely: None. N. Mullen: None. C. Hong: None. C. Hantel: None. W.E. Rainey: None. M.C. Dennedy: None. Adrenocortical carcinoma (ACC) is a rare aggressive cancer with poor survival. Adjuvant mitotane is the only approved drug for treatment of ACC. It improves survival but its use is limited by poor tolerability and drug resistance. For metastatic ACC, combination chemotherapy, using mitotane and etoposide, doxorubicin, and cisplatin improves survival, but efficacy is limited. Better understating the cytotoxic mechanisms of mitotane offers potential to develop improved therapeutic options for ACC. To investigate the underlying mechanisms in vitro, human ACC cells (HAC15 and H295R), in monolayer cell culture were treated with increasing concentrations of mitotane. Cell death was evaluated at 6 and 24 hours using flow cytometry analysis of Annexin V and Sytox Blue. This was complemented by Incucyte ® Live-Cell Analysis System imaging of annexin V and Sytox Blue staining. Expression of the markers of apoptosis, cleaved caspase 3, and necroptosis, phosphorylated MLKL and RIPK1 was measured at 6 and 24 hours. Mitotane significantly reduced the viability of H295R cells at 6 and 24 hours at the therapeutic concentration of 50uM (p&amp;gt;0.0001), thereby demonstrating treatment-sensitivity. In HAC15 cells, a supratherapeutic dose of 200uM was needed to significantly reduce viability (p&amp;gt;0.05) at 24 hours, indicating resistance to mitotane treatment at therapeutic concentrations. There was increasing Annexin V fluorescence with increasing mitotane concentration in H295R and HAC15 cells ar 6 and 24 hours without higher coinciding staining with Sytox Blue. Video analysis demonstrated these findings. Cleaved caspase 3 expression was associated with mitotane-induced cell death in H295R cells at 6 and 24 hours, indicating apoptosis. HAC15 cells demonstrated cleaved caspase 3 expression only at the highest concentration of mitotane exposure (600uM) at 6 hours, without appreciable expression at 24 hours. Phosphorylated-MLKL and RIPK1 expression was seen in controls and all mitotane doses in both cell lines at both timepoints, indicating necroptosis. In this study, H295R cells, representing a treatment-sensitive model of Mitotane undergo both apoptotic and necroptotic cell death at 6 and 24 hours of mitotane exposure. In contrast, HAC15 cells, demonstrated relative treatment resistance to mitotane, and undergo necroptotic cell death only. These results highlight the importance of understanding and targeting non-apoptotic and necroptotic cell death pathways, particularly when evaluating mechanisms of treatment resistance in ACC. Given the difference in the mechanism of cell death in treatment-sensitive and treatment-resistant cells, further exploration of necroptosis is necessary to better understand how ACC cells may manifest treatment resistance. Presentation: 6/1/2024

8538 Pancreatic Islet Adaptations to Hyperglycemia Are Prevented by Glycolytic Inhibition and Amplified by Inhibiting Membrane Depolarization

Abstract Disclosure: N.B. Whitticar: None. B.P. List: None. N. Bruce: None. R. Bertram: None. C.S. Nunemaker: None. Long before type 2 diabetes ensues, pancreatic islets undergo functional changes to compensate for increasing insulin resistance. Primarily, the islets increase their ability to secrete insulin by augmenting the glucose-stimulated insulin secretion (GSIS) pathway. As metabolic syndrome worsens, islets become functionally exhausted, leading to cellular dysfunction and apoptosis. To avoid the negative consequences of this compensatory response, various steps of the GSIS pathway can be attenuated to restore normal functional levels before the islets fail. Determining which inhibitors can prevent the earliest adaptations to hyperglycemia may reveal the processes that play a causal role in islet failure. The chemicals mannoheptulose (MH), diazoxide (DZ), and nifedipine (NP) were chosen to inhibit the glucokinase enzyme, KATP-channel closure, and voltage-gated calcium channels, respectively. CD-1 mouse islets were placed in 20 mM glucose to simulate hyperglycemia along with a concentration of each inhibitory drug that reduced insulin secretion by 30-40%. After 48-hour treatment, glucose-stimulated calcium tests were performed to determine if the treatments could prevent the negative adaptation to hyperglycemia. Only islets treated with MH to reduce glycolytic activity maintained a normal calcium response. Islets in the MH group also retained a strong insulin response to glucose and were not depleted of insulin content. Unexpectedly, inhibition of calcium influx and insulin secretion with DZ or NF caused a substantial increase in basal insulin secretion compared to islets in standard culture (P&amp;lt;0.01, n=6; P=0.06, n=6, respectively). These results indicate that the signaling pathway that causes the adaptation to hyperglycemia lies upstream of KATP channels and downstream of glucokinase. Mathematical modeling using the Integrated Oscillator Model was able to replicate our results and suggests that high rates of glycolytic and mitochondrial metabolism are associated with the signal that adapts islets to hyperglycemia, and that reducing intracellular calcium in the face of high glucose further increases basal insulin secretion. Ongoing studies will determine if metabolic acceleration or altered membrane conductance are responsible for the earliest islet adaptations to hyperglycemia. Our results suggest that reducing metabolic activity, but not calcium influx, prevents adaptations to hyperglycemia in mouse islets. These findings can be applied to potentially prevent the progression of obesity and hyperinsulinemia into type 2 diabetes. Presentation: 6/2/2024

Cytotoxicity, Proapoptotic Activity and Drug-like Potential of Quercetin and Kaempferol in Glioblastoma Cells: Preclinical Insights

Despite the increasing understanding of the pathogenesis of glioblastoma (GBM), treatment options for this tumor remain limited. Recently, the therapeutic potential of natural compounds has attracted great interest. Thus, dietary flavonoids quercetin (QCT) and kaempferol (KMF) were investigated as potential cytostatic agents in GBM. Moreover, the physicochemical properties of QCT and KMF, determining their bioavailability and therapeutic efficiency, were evaluated. We proved that both polyphenols significantly reduced the viability of GBM cells. We also demonstrated that both QCT and KMF evoked the cytotoxic effect in T98G cells via induction of apoptotic cell death as shown by increased activity of caspase 3/7 and caspase 9 together with an overexpression of the cleaved form of PARP. Apoptosis was additionally accompanied by the activation of stress responses in QCT- and KMF-treated cells. Both polyphenols caused oxidative stress and endoplasmic reticulum (ER) stress, as demonstrated by the increased generation of reactive oxygen species (ROS), deregulated expressions of superoxide dismutases (SOD2 and Sod1 on protein and transcriptomic levels, respectively), as well as an overexpression of ERO1α, GRP78, p-JNK, and an up-regulation of Chop, Atf4 and Atf6α genes. The antitumor effect of QCT and KMF was also confirmed in vivo, showing reduced growth of tumor xenografts in the chick chorioallantoic membrane (CAM) experiment. Moreover, electrophoretic light scattering (ELS) was used to measure the zeta potential of cell membranes upon exposition to QCT and KMF. Additionally, on the basis of existing physicochemical data, the drug-likeness score of QCT and KMF was evaluated. Analyses showed that both compounds accomplish Lipinski’s Rule of 5, and they both fit into the criteria of good central nervous system (CNS) drugs. Altogether, our data support the idea that QCT and KMF might be plausible candidates for evaluation as therapeutic agents in preclinical models of glioblastoma.

8038 Targeting Breast Cancer Stem Cells With Oncolytic Mammalian Orthoreovirus (MRV)

Abstract Disclosure: N.I. Roman Ortiz: None. J. Davydova: None. P. Danthi: None. J.H. Ostrander: None. Breast cancer is the most frequently diagnosed malignant cancer in women and is the second leading cause of cancer deaths among women in the United States. Patients with ER+ breast cancer can experience recurrence for more than 10 years after initial diagnosis. Breast cancer stem-like cells (BCSC) are slowly proliferative and exist as a minority sub-population (0-5%) within the tumor. Existing treatments target rapidly dividing cells, and BCSC are unresponsive to these therapies. Due to their self-renewal capabilities, BCSCs can fuel recurrence, metastasis, and resistance to therapies. Notably, no FDA-approved therapeutics selectively target BCSCs. Mammalian orthoreovirus (MRV) is an oncolytic virus tested in clinical trials for many cancer types including metastatic breast cancer. MRV was deemed safe but lacked efficacy as standalone treatment. We tested various laboratory MRV strains (T1L, R2) with T3D, a similar strain to the one evaluated in clinical trials. Our studies suggest that T3D is less effective in killing ER+ breast cancer cells and BCSCs compared to T1L and R2. To understand how T1L and R2 are more effective at killing ER+ breast cancer we aim to test the stages of MRV infection and how MRV induces cell death in ER+ therapy sensitive and resistant cells. MRV can enter cells by receptor mediated endocytosis through attachment with Junctional Adhesion Molecule A (JAM-A) and sialic acids as co-receptors. We have found that T1L attaches to cells in a JAM-A-dependent manner in ER+ sensitive cancer cells, while ER+ therapy resistant cells have increased resistance to JAM-A mediated endocytosis. Previous work has shown that apoptosis is involved in MRV-induced cell death. We found that apoptosis inhibitors in MRV-treated cells increase cell viability, suggesting that MRV-induces apoptotic cell death in ER+ breast cancer cells. Our current studies involve using RNA sequencing as a tool to assess gene expression of ER+ therapy sensitive and resistant cells infected with MRV at early and late stages of infection to determine key genes and pathways associated with cell death.We also aim to generate novel MRV strains with enhanced BCSC killing. We used a forward genetic approach and serially passaged MRV strains in BCSC enriched tumorsphere cultures of MCF-7 paclitaxel resistant (TaxR) cells to generate a selective oncolytic virus that can infect and kill BCSCs. Preliminary data has shown that serially passaged (SP) MRV strains (T1L SP, R2 SP) are more effective in decreasing cell viability and inhibiting tumorsphere formation compared to the parental strains (T1L and R2). Current studies are focused on sequencing SP clones to identify mutations that enhance BCSC death. We expect these studies to enhance MRV virotherapeutics for combined use with clinically relevant inhibitors (i.e. CDK4/6 inhibitors), anti-estrogens, or immunotherapy to prevent and treat metastatic ER+ breast cancer. Presentation: 6/2/2024

8038 Targeting Breast Cancer Stem Cells with Oncolytic Mammalian Orthoreovirus (MRV)

Abstract Disclosure: N.I. Roman Ortiz: None. J. Davydova: None. P. Danthi: None. J.H. Ostrander: None. Breast cancer is the most frequently diagnosed malignant cancer in women and is the second leading cause of cancer deaths among women in the United States. Patients with ER+ breast cancer can experience recurrence for more than 10 years after initial diagnosis. Breast cancer stem-like cells (BCSC) are slowly proliferative and exist as a minority sub-population (0-5%) within the tumor. Existing treatments target rapidly dividing cells, and BCSC are unresponsive to these therapies. Due to their self-renewal capabilities, BCSCs can fuel recurrence, metastasis, and resistance to therapies. Notably, no FDA-approved therapeutics selectively target BCSCs. Mammalian orthoreovirus (MRV) is an oncolytic virus tested in clinical trials for many cancer types including metastatic breast cancer. MRV was deemed safe but lacked efficacy as standalone treatment. We tested various laboratory MRV strains (T1L, R2) with T3D, a similar strain to the one evaluated in clinical trials. Our studies suggest that T3D is less effective in killing ER+ breast cancer cells and BCSCs compared to T1L and R2. To understand how T1L and R2 are more effective at killing ER+ breast cancer we aim to test the stages of MRV infection and how MRV induces cell death in ER+ therapy sensitive and resistant cells. MRV can enter cells by receptor mediated endocytosis through attachment with Junctional Adhesion Molecule A (JAM-A) and sialic acids as co-receptors. We have found that T1L attaches to cells in a JAM-A-dependent manner in ER+ sensitive cancer cells, while ER+ therapy resistant cells have increased resistance to JAM-A mediated endocytosis. Previous work has shown that apoptosis is involved in MRV-induced cell death. We found that apoptosis inhibitors in MRV-treated cells increase cell viability, suggesting that MRV-induces apoptotic cell death in ER+ breast cancer cells. Our current studies involve using RNA sequencing as a tool to assess gene expression of ER+ therapy sensitive and resistant cells infected with MRV at early and late stages of infection to determine key genes and pathways associated with cell death.We also aim to generate novel MRV strains with enhanced BCSC killing. We used a forward genetic approach and serially passaged MRV strains in BCSC enriched tumorsphere cultures of MCF-7 paclitaxel resistant (TaxR) cells to generate a selective oncolytic virus that can infect and kill BCSCs. Preliminary data has shown that serially passaged (SP) MRV strains (T1L SP, R2 SP) are more effective in decreasing cell viability and inhibiting tumorsphere formation compared to the parental strains (T1L and R2). Current studies are focused on sequencing SP clones to identify mutations that enhance BCSC death. We expect these studies to enhance MRV virotherapeutics for combined use with clinically relevant inhibitors (i.e. CDK4/6 inhibitors), anti-estrogens, or immunotherapy to prevent and treat metastatic ER+ breast cancer. Presentation: 6/2/2024