Cell Cycle Markers Research Articles

Abstract 4136030: Fatty acids disturb cardiomyocyte proliferation by increasing PDK4 and HMGCS2 via PPARδ activation

Background: Almost all cardiac diseases are difficult to cure entirely because cardiomyocytes rarely proliferate to recover cardiac damage. In fact, most mammals have a capacity to regenerate cardiomyocytes immediately after birth. Newborn infant drastically changes cardiac metabolism from glycolysis to oxidative phosphorylation using fatty acids. Previous research revealed that lipid metabolism had a negative influence on cardiomyocyte cell cycle but the mechanism has not been clarified completely. Objective: This study was performed to elucidate the way fatty acid metabolism affects cardiomyocyte proliferation. Methods and results: Isolated and cultured neonatal rat cardiomyocytes (NRCM) were treated with the mixture of palmitic acid, oleic acid, and L-carnitine (FA mix) for 24 hours. Realtime RT-PCR revealed that FA mix increased the mRNA expressions of pyruvate dehydrogenase kinase 4 (PDK4), a fatty acid metabolism regulator, and HMG-CoA synthase 2 (HMGCS2), a ketogenic factor, as well as β-oxidation-related enzymes in dose dependent manner. Simultaneously, the results of immunofluorescent staining showed that FA mix decreased cardiomyocytes expressing Ki67, a cell cycle marker. GW501516, a peroxisome proliferator-activated receptor δ (PPARδ) agonist, also increased fatty acid metabolism factors with the reduction of Ki67 positive cardiomyocytes, whereas fenofibrate, a PPARα agonist, or pioglitazone, a PPARγ agonist, caused little or no change in these phenotypes. Moreover, NRCM pretreated with GSK3787, a PPARδ antagonist, before FA mix stimulation suppressed the upregulations of fatty acid metabolism factors and the reduction of Ki67 expressing cardiomyocytes. Finally, the lentiviral vectors which expressed PDK4 or HMGCS2 were produced to investigate these proteins suppressed NRCM cell cycle directly. Either overexpressing PDK4 or HMGCS2 decreased Ki67 positive NRCM without the upregulation of each other or β-oxidation-related enzymes. Conclusion: Fatty acids disturbed NRCM proliferation by upregulating PDK4 and HMGCS2 through the activation of PPARδ independently from β-oxidation.

Abstract 4112620: Cardiomyocyte-specific Increases in Forkhead Box M1 (FoxM1) Expression May Promote Cardiomyocyte Proliferation and Improve Recovery from Myocardial Injury in Mice and Pigs

Background: The cardiomyocytes (CMs) can not regenerate after myocardial infarction (MI) in adult mammals. FoxM1 is essential for cell proliferation. Targeted deletion of the Foxm1 in mice leads to serious cardiac proliferation defects and embryo death. The primary aim of this study was to demonstrate that the Specific Modified mRNA Translation System (SMRTs) can specifically overexpress FoxM1 in CMs and observe the benefits of overexpressing FoxM1 on myocardial repair in mice and pigs with myocardial injury. Methods: The FoxM1-CM SMRTs is composed of two modRNA constructs: one encoding L7Ae regulates the specific expression of FoxM1 on the other coding chain in CMs and inhibits its expression in non-cardiomyocytes through he CM-specific microRNAs miR-1 and miR-208 on L7Ae coding chain. Myocardial-specific expression of FoxM1-CM SMRTs and its proliferation-promoting effect were detected in hiPSC-CM (human-induced pluripotent stem cell-derived cardiomyocyte), mouse and pig models (days 3 after FoxM1-CM SMRTs treatment). In vivo experiments were conducted in both mouse and pigs with LAD (left anterior descending) ligation. The effects of FoxM1-CM SMRTs on cardiac function, MI size and hypertrophy in mice and pig models were detected after 4 weeks of FoxM1-CM SMRTs treatment. Results: FoxM1 was abundantly expressed in postmitotic CMs after transfection with the FoxM1-CM SMRTs, accompanied by activation of cell-cycle and proliferation markers (Ki67, PH3 and Aurora B kinase) and an increase in cell number. When the GFP-CM SMRTs was injected into mouse hearts with MI, GFP was only expressed in CMs, but not in non-CMs. Compared with the MI group, FoxM1-CM SMRTs significantly increased CM proliferation (days 3 after treatment administration in mice and pigs), improved left-ventricular ejection fractions (days 10 and 28 in both species) and hypertrophy, and reduced MI size (days 28 in both species). Conclusion: Intramyocardial injections of the FoxM1-CM SMRTs promoted CM proliferation, reduced MI size, and improved cardiac function in small and large mammals with acute myocardial infarction.

DDDR-21. MPT0G521 AS A DUAL INHIBITOR OF LSD1 AND HDAC: A POTENTIAL THERAPEUTIC AGENT AGAINST PARENTAL AND TEMOZOLOMIDE-RESISTANT GLIOBLASTOMA MULTIFORME

Abstract INTRODUCTION Glioblastoma multiforme (GBM) is an aggressive brain tumor with limited treatment options and poor prognosis. Resistance to temozolomide (TMZ), the standard chemotherapy for GBM, further complicates treatment. This study investigates the effects of MPT0G521, a dual inhibitor of LSD1 and HDAC, on both parental and TMZ-resistant GBM cells to determine its potential as a therapeutic agent. MATERIALS AND METHODS TMZ and MPT0G521 were introduced in our study. Human GBM cell lines A172 and patient-derived primary GBM cells Pt#3, along with their TMZ-resistant counterparts, were cultured under specified conditions. Assays conducted include cell proliferation (MTT), colony formation, cell cycle analysis via flow cytometry, and western blot analysis for protein expression. Statistical significance was evaluated using ANOVA. RESULTS MPT0G521 exhibited significant anti-proliferative activity and toxicity against both parental and TMZ-resistant GBM cells in a dose- and time-dependent manner. Treatment with MPT0G521 led to reduced cell viability and colony formation. Cell cycle analysis revealed G2M phase arrest and increased subG1 phase, indicating cell cycle disruption and apoptosis. Western blot analysis showed upregulation of histone H3 methylation and acetylation, confirming the dual inhibitory action of MPT0G521 on LSD1 and HDAC. Additionally, MPT0G521 modulated markers of cell cycle and apoptosis, including increased levels of cleaved caspase-3 and PARP. CONCLUSION MPT0G521 demonstrates potential as an effective therapeutic agent against GBM by inhibiting cell proliferation, inducing cell cycle arrest, and promoting apoptosis in both parental and TMZ-resistant cells. These findings support further investigation of MPT0G521 as a promising treatment for GBM, particularly in cases resistant to standard chemotherapy.

Biochanin A Induces Apoptosis in MCF‐7 Breast Cancer Cells through Mitochondrial Pathway and Pi3K/AKT Inhibition

ABSTRACTThe study aimed to investigate the molecular mechanisms by which Biochanin A inhibits proliferation and induces apoptosis in breast cancer cells. Cultured MCF‐7 cells were divided into four groups: Group 1‐control, while Groups 2, 3, and 4 were treated with Biochanin A at different concentrations. After treatment, the cells were monitored, and morphological changes were examined after 24 h of incubation. The results showed that Biochanin A inhibited cell proliferation, increased reactive oxygen species formation, and induced apoptosis. Furthermore, western blot analysis revealed that Biochanin A‐treated cells exhibited lower expression of the Bcl‐2, p‐PI3K and p‐AKT and higher expression of proapoptotic genes, including Bax, Caspase‐3, Caspase‐9, and cytochrome c. Additionally, PCR array analysis indicated that the gene expression levels of cyclin D3, cyclin B1, CDK1, CDK2, and CDK4 were downregulated, while the expression levels of p21, p27, and p53 were significantly upregulated. These results suggest that Biochanin A can suppress the viability of breast cancer cells and induce apoptosis via the mitochondrial pathway, along with inhibition of the Pi3K/Akt signaling pathway and modulation of cell cycle markers.

MLLT3 knockdown suppresses proliferation and cell mobility in human lung adenocarcinoma.

Lung cancer is emerging as one of the most frequently encountered malignancies around the world that carries high morbidity and mortality. Lung adenocarcinoma (LUAD) has become the most common subtype of lung cancer. MLLT3 or named AF9 was first characterized in acute myeloid leukemia and can downregulate the expression of several critical genes. The aim of this study was to explore the function of MLLT3 in the progression of LUAD and related molecular mechanisms. Immunohistochemistry was employed to assess MLLT3 expression in LUAD tissues, while quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were utilized to detect MLLT3 expression levels in lung adenocarcinoma cell lines. These results revealed a significant overexpression of MLLT3 in LUAD cell lines and tissues. We further uncovered an association between MLLT3 expression profiles in LUAD tissues and metastasis, as well as TNM stage. Survival analysis showed that elevated MLLT3 correlated with a poorer survival rate. We also found that MLLT3 knockdown repressed LUAD cells invasion, migration, and proliferation in vitro, while inducing cell cycle arrest and apoptosis of LUAD cells. Moreover, knocking down MLLT3 inhibited tumor growth in vivo. Specific markers of apoptosis, cell cycle, epithelial-mesenchymal transition (EMT), and MLLT3-induced signaling were examined by Western blot. We demonstrated that MLLT3 knockdown inhibited the activity of the EGFR-MAPK/ERK signaling pathway, and MLLT3 might be a novel diagnostic biomarker and therapeutic target in lung adenocarcinomas.

Cell-cycle phase progression analysis identifies three unique phenotypes in soft tissue sarcoma

PurposeLoddo et al. (Br J Cancer 100:959–70, 2009) established the prognostic significance of cell cycle markers and "Cell-Cycle Phenotypes" in breast carcinoma. This study aims to 1) identify prognostic cell-cycle markers in sarcoma, and 2) assess the prognostic potential of specific cell-cycle phenotypes in sarcoma.MethodsTissue samples from 128 soft tissue sarcomas were stained for four cell cycle-specific markers: Mcm2, Geminin, Plk1, and H3S10ph. Only primary soft tissue tumors (liposarcoma, leiomyosarcoma, synovial sarcoma, and undifferentiated pleomorphic sarcoma) were included in the analysis. Any tumor coming from a recurrent or metastatic lesion were excluded from the analysis. Three cell-cycle phenotypes (I, II, III) were derived from marker expression patterns. Prognostic significance was evaluated in a subset of primary soft tissue sarcomas using Cox regression for survival analysis.ResultsCompared to phenotype I, the phenotype III tumors had a decreased 5-year overall survival (HR 6.81 [2.36–19.61]; p = < 0.001), 5-year disease-free survival (HR 1.07 (1.02–1.18); p = 0.004), and 5-year metastasis-free survival (HR 4.34 [1.58–11.93]; p = 0.004).High expression of Plk1 was associated with decreased 5-year overall survival (HR: 4.04 CI [1.21–6.67; p = 0.02) and 5-year metastasis-free survival (HR: 2.91 CI [1.15–7.37]; p = 0.03). Geminin was also found to have a decreased 5-year overall survival (HR:2.84 CI [1.21–6.67]; p = 0.02). No statistical difference in prognostication were noted between phenotypes and the AJCC system.ConclusionsWe identified three unique sarcoma cell cycle phenotypes that have prognostic significance. This performs similarly to the AJCC staging system.

Umbilical Cord Mesenchymal Stem Cell-Derived Extracellular Vesicles as Natural Nanocarriers in the Treatment of Nephrotoxic Injury In Vitro.

This study investigates the delivery of miRNA-126 and anti-miRNA-126 via UC-EVs as natural nanocarriers for treating nephrotoxic injury in vitro. The umbilical cord-derived mesenchymal stem cell and UC-EVs were characterized according to specific guidelines. Rat kidney proximal tubular epithelial cells (tubular cells) were exposed to nephrotoxic injury through of gentamicin and simultaneously treated with UC-EVs carrying miRNA-126 or anti-miRNA-126. Specific molecules that manage cell cycle progression, proliferation cell assays, and newly synthesized DNA and DNA damage markers were evaluated. We observed significant increases in the expression of cell cycle markers, including PCNA, p53, and p21, indicating a positive cell cycle regulation with newly synthesized DNA via BrDU. The treatments reduced the expression of DNA damage marker, such as H2Ax, suggesting a lower rate of cellular damage. The UC-EVs, acting as natural nanocarriers of miRNA-126 and anti-miRNA-126, offer nephroprotective effects in vitro. Additionally, other components in UC-EVs, such as proteins, lipids, and various RNAs, might also contribute to these effects.

UBE2Q1 as a novel cancer biomarker for lung adenocarcinoma: Short Title: Oncogenic function of UBE2Q1 in lung adenocarcinoma

PurposeUbiquitin-conjugating enzymes (E2s) participate in various tumor-promoting processes. UBE2Q1 is a member of the E2 family. This research aimed to detect the expression level of UBE2Q1 in human lung adenocarcinoma and to study its malignant biological function. MethodsWestern blot, qRT-PCR and immunohistochemistry was used to measure the expression of UBE2Q1 in human lung adenocarcinoma tissues. The association between UBE2Q1 expression and clinic-pathological variables in 99 lung adenocarcinoma samples was analyzed by immunohistochemistry. In vitro experiment, establishing UBE2Q1 knockdown pattern, the markers of apoptosis, cell cycle and epithelial-mesenchymal transition (EMT) were analyzed by Western blot. CCK8, colony formation, Transwell and invasion assay analyzed the effect of UBE2Q1 knockdown on the proliferation, metastasis and invasion of lung cancer cells. ResultsUBE2Q1 was overexpressed in lung adenocarcinoma, and the expression level of UBE2Q1 was related with TNM stage, tumor size, and lymph node metastasis. The high level of UBE2Q1 expression was also associated with poor survival and was an independent risk factor. In vitro, It was also confirmed that steady downregulation of UBE2Q1 could promote apoptosis, induce G2/M cell cycle arrest and regulate EMT. UBE2Q1 silencing dramatically reduce lung tumor cells proliferation, migration and invasion capacities. ConclusionsUBE2Q1 may serve as a prognostic biomarker and a new therapeutic target of lung adenocarcinoma.

Kaempferol Synergistically Enhances Cisplatin-induced Apoptosis and Cell Cycle Arrest in Colon Cancer Cells.

Colon cancer remains a significant global health concern, necessitating the continuous exploration of novel therapeutic strategies. Cisplatin is a first-line chemotherapy medication that is frequently used to treat patients for a variety of malignancies, including colon cancer. However, a major obstacle to its clinical usefulness is acquired resistance. This research investigates the synergistic effects of kaempferol, a natural flavonoid with known anti-cancer properties, in combination with cisplatin, in colon cancer cells. Our study employed colon cancer cell lines to evaluate the individual and combined cytotoxic effects of kaempferol and cisplatin. The results demonstrated a notable enhancement in the cytotoxicity of colon cancer cells when treated with a combination of kaempferol and cisplatin compared to individual treatments. This synergistic effect was further characterized by an increase in apoptosis, as evidenced by morphological changes and biochemical markers of apoptosis and cell cycle. The investigations revealed that the combined treatment led to the modulation of key apoptotic pathways, including the upregulation of pro-apoptotic factors and downregulation of anti-apoptotic factors. Additionally, the synergistic effect was associated with the inhibition of cell proliferation and induction of cell cycle arrest. The findings of this study suggest that the combination of kaempferol and cisplatin holds promise as a potent therapeutic strategy for colon cancer treatment, potentially enhancing the efficacy of conventional chemotherapy while minimizing adverse effects. Further in-depth investigations, including in vivo studies, are warranted to validate these findings and explore the translational potential of this synergistic approach in clinical settings.

Targeting TRIM26: Unveiling an Oncogene and Identification of Plant Metabolites as a Potential Therapeutics for Breast Cancer.

Breast cancer is the major cause of cancer-related mortality and frequent malignancies among women worldwide. The TRIM (Tripartite Motif) protein family is a broad and diverse set of proteins that contain a conserved structural motif known as the tripartite motif, which comprises of three different domains, B-box domain, Coiled-coil domain and RBR (Ring-finger, B-box, and coiled-coil) domain. TRIM proteins are involved in regulating cancer growth and metastasis. However, TRIM proteins are still unexplored in cancer cell regulation. In this study, by using a cancer database expression of all TRIM proteins was determined in breast cancer. Out of 77 TRIM genes, 16 genes were upregulated in breast cancer. Here, the upregulated TRIM26 gene's role is not yet explored in breast cancer. Indeed, TRIM26 is upregulated in 21 cancer types out of 33 cancer types. To investigate the role of TRIM26 in breast cancer, siRNA-mediated gene silencing was carried out in MCF-7 and MDA-MB 231 breast cancer cells. Reduced expression of TRIM 26 decreased cancer cell proliferation, migration and invasion with simultaneous reduction of various proliferative, cell cycle and mesenchymal markers and upregulation of epithelial markers. Further, docking studies found potential novel plant metabolites. Thus, targeting TRIM26 may provide a novel therapeutic approach for breast cancer treatment.

Synthetic lethality between ATR and POLA1 reveals a potential new target for individualized cancer therapy

The ATR-CHK1 pathway plays a fundamental role in the DNA damage response and is therefore an attractive target in cancer therapy. The antitumorous effect of ATR inhibitors is at least partly caused by synthetic lethality between ATR and various DNA repair genes. In previous studies, we have identified members of the B-family DNA polymerases as potential lethal partner for ATR, i.e. POLD1 and PRIM1. In this study, we validated and characterized the synthetic lethality between ATR and POLA1.First, we applied a model of ATR-deficient DLD-1 human colorectal cancer cells to confirm synthetic lethality by using chemical POLA1 inhibition. Analyzing cell cycle and apoptotic markers via FACS and Western blotting, we were able to show that apoptosis and S phase arrest contributed to the increased sensitivity of ATR-deficient cancer cells towards POLA1 inhibitors. Importantly, siRNA-mediated POLA1 depletion in ATR-deficient cells caused similar effects in regard to impaired cell viability and cumulation of apoptotic markers, thus excluding toxic effects of chemical POLA1 inhibition. Conversely, we demonstrated that siRNA-mediated POLA1 depletion sensitized several cancer cell lines towards chemical inhibition of ATR and its main effector kinase CHK1.In conclusion, the synthetic lethality between ATR/CHK1 and POLA1 might represent a novel and promising approach for individualized cancer therapy: First, alterations of POLA1 could serve as a screening parameter for increased sensitivity towards ATR and CHK1 inhibitors. Second, alterations in the ATR-CHK1 pathway might predict in increased sensitivity towards POLA1 inhibitors.

Synergistic Efficacy of CDK4/6 Inhibitor Abemaciclib and HDAC Inhibitor Panobinostat in Pancreatic Cancer Cells.

The current 5-year survival rate of pancreatic cancer is about 12%, making it one of the deadliest malignancies. The rapid metastasis, acquired drug resistance, and poor patient prognosis necessitate better therapeutic strategies for pancreatic ductal adenocarcinoma (PDAC). Multiple studies show that combining chemotherapeutics for solid tumors has been successful. Targeting two distinct emerging hallmarks, such as non-mutational epigenetic changes by panobinostat (Pan) and delayed cell cycle progression by abemaciclib (Abe), inhibits pancreatic cancer growth. HDAC and CDK4/6 inhibitors are effective but are prone to drug resistance and failure as single agents. Therefore, we hypothesized that combining Abe and Pan could synergistically and lethally affect PDAC survival and proliferation. Multiple cell-based assays, enzymatic activity experiments, and flow cytometry experiments were performed to determine the effects of Abe, Pan, and their combination on PDAC cells and human dermal fibroblasts. Western blotting was used to determine the expression of cell cycle, epigenetic, and apoptosis markers. The Abe-Pan combination exhibited excellent efficacy and produced synergistic effects, altering the expression of cell cycle proteins and epigenetic markers. Pan, alone and in combination with Abe, caused apoptosis in pancreatic cancer cells. Abe-Pan co-treatment showed relative safety in normal human dermal fibroblasts. Our novel combination treatment of Abe and Pan shows synergistic effects on PDAC cells. The combination induces apoptosis, shows relative safety, and merits further investigation due to its therapeutic potential in the treatment of PDAC.

Multiple-heated cooking oil promotes early hepatic and renal senescence in adult male rats: the potential regenerative capacity of oleuropein

For economic purposes, cooking oil is repeatedly heated in food preparation, which imposes serious health threats. This study investigated the detrimental effects of multiple-heated cooking oil (MHO) on hepatic and renal tissues with particular focusing on cellular senescence (CS), and the potential regenerative capacity of oleuropein (OLE). Adult male rats were fed MHO-enriched diet for 8 weeks and OLE (50 mg/kg, PO) was administered daily for the last four weeks. Liver and kidney functions and oxidative stress markers were measured. Cell cycle markers p53, p21, cyclin D, and proliferating cell nuclear antigen (PCNA) were evaluated in hepatic and renal tissues. Tumor necrosis factor-α (TNF-α) and Bax were assessed by immunohistochemistry. General histology and collagen deposition were also examined. MHO disturbed hepatic and renal structures and functions. MHO-fed rats showed increased oxidative stress, TNF-α, Bax, and fibrosis in liver and kidney tissues. MHO also enhanced the renal and hepatic expression of p53, p21, cyclin D and PCNA. On the contrary, OLE mitigated MHO-induced oxidative stress, inflammatory burden, apoptotic and fibrotic changes. OLE also suppressed CS and preserved kidney and liver functions. Collectively, OLE displays marked regenerative capacity against MHO-induced hepatic and renal CS, via its potent antioxidant and anti-inflammatory effects.

Iron Regulates Cellular Proliferation by Enhancing the Expression of Glucose Transporter GLUT3 in the Liver.

Iron is often accumulated in the liver during pathological conditions such as cirrhosis and cancer. Elevated expression of glucose transporters GLUT1 and GLUT3 is associated with reduced overall survival in patients with hepatocellular carcinoma. However, it is not known whether iron can regulate glucose transporters and contribute to tumor proliferation. In the present study, we found that treatment of human liver cell line HepG2 with ferric ammonium citrate (FAC) resulted in a significant upregulation of GLUT3 mRNA and protein in a dose-dependent manner. Similarly, iron accumulation in mice fed with high dietary iron as well as in mice injected intraperitoneally with iron dextran enhanced the GLUT3 expression drastically in the liver. We demonstrated that iron-induced hepatic GLUT3 upregulation is mediated by the LKB1/AMPK/CREB1 pathway, and this activation was reversed when treated with iron chelator deferiprone. In addition, inhibition of GLUT3 using siRNA prevented iron-mediated increase in the expression of cell cycle markers and cellular hyperproliferation. Furthermore, exogenous sodium beta-hydroxybutyrate treatment prevented iron-mediated hepatic GLUT3 activation both in vitro and in vivo. Together, these results underscore the importance of iron, AMPK, CREB1 and GLUT3 pathways in cell proliferation and highlight the therapeutic potential of sodium beta-hydroxybutyrate in hepatocellular carcinoma with high GLUT3 expression.

Polysaccharides from Basella alba Protect Post-Mitotic Neurons against Cell Cycle Re-Entry and Apoptosis Induced by the Amyloid-Beta Peptide by Blocking Sonic Hedgehog Expression.

The amyloid-beta peptide (Aβ) is the neurotoxic component in senile plaques of Alzheimer's disease (AD) brains. Previously we have reported that Aβ toxicity is mediated by the induction of sonic hedgehog (SHH) to trigger cell cycle re-entry (CCR) and apoptosis in post-mitotic neurons. Basella alba is a vegetable whose polysaccharides carry immunomodulatory and anti-cancer actions, but their protective effects against neurodegeneration have never been reported. Herein, we tested whether polysaccharides derived from Basella alba (PPV-6) may inhibit Aβ toxicity and explored its underlying mechanisms. In differentiated rat cortical neurons, Aβ25-35 reduced cell viability, damaged neuronal structure, and compromised mitochondrial bioenergetic functions, all of which were recovered by PPV-6. Immunocytochemistry and western blotting revealed that Aβ25-35-mediated induction of cell cycle markers including cyclin D1, proliferating cell nuclear antigen (PCNA), and histone H3 phosphorylated at Ser-10 (p-Histone H3) in differentiated neurons was all suppressed by PPV-6, along with mitigation of caspase-3 cleavage. Further studies revealed that PPV-6 inhibited Aβ25-35 induction of SHH; indeed, PPV-6 was capable of suppressing neuronal CCR and apoptosis triggered by the exogenous N-terminal fragment of sonic hedgehog (SHH-N). Our findings demonstrated that, in the fully differentiated neurons, PPV-6 exerts protective actions against Aβ neurotoxicity via the downregulation of SHH to suppress neuronal CCR and apoptosis.

Mesenchymal Stromal Cells Nanovesicles Carry microRNA with Nephroprotective Proprieties Regardless of Aging.

The effects of aging on the paracrine mechanism and in the production and action of MSCs-EV and their cargos of miR-26a and siRNA-26a for the treatment of tubular renal cells under nephrotoxicity injury remain unelucidated. The purpose of this study was to evaluate MSCs-EV of different ages and their ability to deliver the cargos of miR-26a and siRNA-26a to target renal tubular cells affected by nephrotoxicity injury. In a model of gentamicin-induced nephrotoxicity, renal tubular cells treated with MSCs-EV expressing or not expressing microRNA-26a were analyzed. Western blotting was utilized to evaluate cell cycle markers, and MTT assay was utilized to evaluate auto-renovation capacity. Tubular cells under nephrotoxicity injury showed decreased proliferative capacity, but the treatment in the tubular renal cells under nephrotoxicity injury with MSCs-EV expressing microRNA-26a showed nephroprotective effects, regardless of EV age. While the treatment with EV-mediated siRNA-26a failed to preserve the nephroprotective effects equally, regardless of age. Mesenchymal stromal cell nanovesicles carry microRNA with nephroprotective proprieties regardless of aging.

ATRT-09. MULTI-OMICS SEQUENCING OF ATYPICAL TERATOID RHABDOID TUMORS UNVEILS A SHARED GROUND-STATE POPULATION PROMOTING SUBGROUP-SPECIFIC DIFFERENTIATION TRAJECTORIES

Abstract BACKGROUND Atypical teratoid rhabdoid tumors (ATRTs) remain a significant clinical challenge in pediatric neurooncology. Despite the simplicity of the genomic profile, mostly characterized by the functional loss of SMARCB1 and in rare cases SMARCA4, ATRTs are molecularly and epigenetically diverse, with three main molecular subgroups identified: ATRT-TYR, ATRT-SHH and ATRT-MYC. METHODS To address the lack of effective mechanism-of-action based treatments and comprehend the biology of these subgroups, we conducted 10X single-nucleus transcriptome (n = 12) and multiome (transcriptome + ATAC) (n = 7) sequencing on tumor samples (ATRT-TYR = 6, ATRT-SHH = 9, ATRT-MYC = 4). Validation datasets included 10X single-cell transcriptomics (n = 1), 10X single-nucleus transcriptomics of cell lines (n = 5), and single-cell (n = 3) and single-nucleus (n = 9) SMART-seq transcriptomics. Separation of malignant cells from tumor microenvironment (TME) cells was achieved by comparison of expression profiles against literature-based marker genesets of normal cell types. Tumor cell populations were characterized based on enrichment in fetal cell types and recurrent tumor programs across cancer types, coupled with non-negative matrix factorization (NMF) and differential expression analyses. RESULTS ATRT-TYR exhibited choroid plexus-like and cilia-like cell populations, ATRT-SHH displayed radial glia-like, OPC-like and NPC-like cell populations and ATRT-MYC mainly demonstrated a mesenchymal-like cell population. Each subgroup represented unique differentiation trajectories. However, we identified a population of intermediate neuronal precursor-like cells (IPC-like) shared across all subgroups, expressing markers of pluripotent stem cells and cell cycle. RNA + ATAC transcription factor (TF) enrichment analysis for IPC-like cells revealed TFs linked to each subgroup’s differentiation trajectory, suggesting IPC-like cells as a putative ground-state tumor cell population driving differentiation of each subgroup. Functional validation of these findings in ATRT organoid models is currently ongoing. CONCLUSIONS This study elucidates defined ATRT subgroup-specific differentiation trajectories that may provide guidance for the development of subgroup-based therapies.

Cellular mechanisms mediating the anti-cancer effects of carnosol on gingiva carcinoma

Carnosol, a rosemary polyphenol, displays anticancer properties and is suggested as a safer alternative to conventional surgery, radiotherapy, and chemotherapy. Given that its effects on gingiva carcinoma have not yet been investigated, the aim of this study was to explore its anti-tumor selectivity and to unravel its underlying mechanisms of action. Hence, oral tongue and gingiva carcinoma cell lines exposed to carnosol were analyzed to estimate cytotoxicity, cell viability, cell proliferation, and colony formation potential as compared with those of normal cells. Key cell cycle and apoptotic markers were also measured. Finally, cell migration, oxidative stress, and crucial cell signaling pathways were assessed. Selective anti-gingiva carcinoma activity was disclosed. Overall, carnosol mediated colony formation and proliferation suppression in addition to cytotoxicity induction. Cell cycle arrest was highlighted by the disruption of the c-myc oncogene/p53 tumor suppressor balance. Carnosol also increased apoptosis, oxidative stress, and antioxidant activity. On a larger scale, the alteration of cell cycle and apoptotic profiles was also demonstrated by QPCR array. This was most likely achieved by controlling the STAT5, ERK1/2, p38, and NF-ĸB signaling pathways. Lastly, carnosol reduced inflammation and invasion ability by modulating IL-6 and MMP9/TIMP-1 axes. This study establishes a robust foundation, urging extensive inquiry both in vivo and in clinical settings, to substantiate the efficacy of carnosol in managing gingiva carcinoma.

Prenatal treatment with preimplantation factor improves early postnatal neurogenesis and cognitive impairments in a mouse model of Down syndrome

Down syndrome (DS) is a genetic disease characterized by a supernumerary chromosome 21. Intellectual deficiency (ID) is one of the most prominent features of DS. Central nervous system defects lead to learning disabilities, motor and language delays, and memory impairments. At present, a prenatal treatment for the ID in DS is lacking. Subcutaneous administration of synthetic preimplantation factor (sPIF, a peptide with a range of biological functions) in a model of severe brain damage has shown neuroprotective and anti-inflammatory properties by directly targeting neurons and microglia. Here, we evaluated the effect of PIF administration during gestation and until weaning on Dp(16)1Yey mice (a mouse model of DS). Possible effects at the juvenile stage were assessed using behavioral tests and molecular and histological analyses of the brain. To test the influence of perinatal sPIF treatment at the adult stage, hippocampus-dependent memory was evaluated on postnatal day 90. Dp(16)1Yey pups showed significant behavioral impairment, with impaired neurogenesis, microglial cell activation and a low microglial cell count, and the deregulated expression of genes linked to neuroinflammation and cell cycle regulation. Treatment with sPIF restored early postnatal hippocampal neurogenesis, with beneficial effects on astrocytes, microglia, inflammation, and cell cycle markers. Moreover, treatment with sPIF restored the level of DYRK1A, a protein that is involved in cognitive impairments in DS. In line with the beneficial effects on neurogenesis, perinatal treatment with sPIF was associated with an improvement in working memory in adult Dp(16)1Yey mice. Perinatal treatment with sPIF might be an option for mitigating cognitive impairments in people with DS.

Abstract PO5-23-10: Development of a long-term in vitro assay able to identify compounds that can overcome resistance to CDK4/6 inhibitor plus endocrine therapy in ER+ HER2- breast cancer

Abstract CDK4/6 inhibitor plus endocrine therapy (ET) has emerged as the standard of care first line therapy in ER+ HER2- breast cancer. While this combination has shown the ability to extend overall survival, nearly all patients acquire resistance and progress after 2-3 years. Subsequently, interest has turned to identifying a third partner compound that can be integrated into the CDK4/6i plus ET backbone regimen with the goal of overcoming resistance and driving a deeper response. However, a comprehensive assay-based workflow proficient in identifying compounds with the most promising potential is lacking. To fill this need, we set out to develop a high-throughput in vitro assay with relevant multi-faceted readouts to assess the efficacy of potential triplet combinations using 12 human ER+ breast cancer lines. For this assay, cells were engineered to express nuclear RFP to enable accurate cell counting using basic imaging techniques in 384 well plates. Each third partner compound was tested at two different doses and, in addition to the triplet combination (CDK4/6i + ET + third partner), single agent as well as double agent combinations were investigated. The assay was imaged and re-dosed every 5 days until day 15. On day 15, the compounds were washed out and the cells underwent a 25-day drug holiday to monitor relapse. Duplicate plates of all conditions were monitored and imaged every two hours for 24 hours for live cell staining of apoptosis markers. Additional duplicate plates were fixed and stained on days 5 and 15 for markers of senescence and cell cycle. Images were subsequently fed into a python-based algorithm to determine the percentage of cell population expressing the various markers and phenotypic correlates were extracted. We are looking for triplet combinations that induce a deeper cell cycle arrest, senescence, and/or cell death compared with the CDK4/6 inhibitor plus ET only treatment. Our drug holiday results will help elucidate the treatments able to continue to induce suppression once washed out, indicating treatment options that may induce long-lasting, possibly irreversible effects on the cells. Finally, by extracting phenotypic correlates from brightfield images we hope to cluster the various compounds in their effects across cell lines of diverse backgrounds to help understand the best way to benefit multiple patient populations. Overall, the assay will be able to identify and differentiate various therapeutic combinations based on cell count, senescence, and cell death. The format of this assay enables depth of analysis not accessible using other techniques such as FACS, including full dose-response curves, combination matrices, and longitudinal analyses. Additionally, the assay can be modified to evaluate any number of cellular markers and can be useful across a number of applications. The approach developed here will be foundational in discovering next-step strategies for patients with therapy resistance. Citation Format: Stephanie Kronstadt, Neil Umbreit, Matt Niederst, Rens Janssens. Development of a long-term in vitro assay able to identify compounds that can overcome resistance to CDK4/6 inhibitor plus endocrine therapy in ER+ HER2- breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-23-10.