Upregulation Of TP53 Research Articles

Clonal landscape and clinical outcomes of telomere biology disorders: somatic rescue and cancer mutations

AbstractTelomere biology disorders (TBDs), caused by pathogenic germ line variants in telomere-related genes, present with multiorgan disease and a predisposition to cancer. Clonal hematopoiesis (CH) as a marker of cancer development and survival in TBDs is poorly understood. Here, we characterized the clonal landscape of a large cohort of 207 patients with TBD with a broad range of age and phenotype. CH occurred predominantly in symptomatic patients and in signature genes typically associated with cancers: PPM1D, POT1, TERT promoter (TERTp), U2AF1S34, and/or TP53. Chromosome 1q gain (Chr1q+) was the commonest karyotypic abnormality. Clinically, multiorgan involvement and CH in TERTp, TP53, and splicing factor genes were associated with poorer overall survival. Chr1q+ and splicing factor or TP53 mutations significantly increased the risk of hematologic malignancies, regardless of clonal burden. Chr1q+ and U2AF1S34 mutated clones were premalignant events associated with the secondary acquisition of mutations in genes related to hematologic malignancies. Similar to the known effects of Chr1q+ and TP53-CH, functional studies demonstrated that U2AF1S34 mutations primarily compensated for aberrant upregulation of TP53 and interferon pathways in telomere-dysfunctional hematopoietic stem cells, highlighting the TP53 pathway as a canonical route of malignancy in TBD. In contrast, somatic POT1/PPM1D/TERTp mutations had distinct trajectories unrelated to cancer development. With implications beyond TBD, our data show that telomere dysfunction is a strong selective pressure for CH. In TBD, CH is a poor prognostic marker associated with worse overall survival. The identification of key regulatory pathways that drive clonal transformation in TBD allows for the identification of patients at a higher risk of cancer development.

Enhancing mitotane efficacy in adrenocortical carcinoma by calcineurin inhibition with cyclosporine A

Aims: The aim of this study is to determine the effect of calcineurin (CaN) in adrenocortical cancer (ACC) cells, which is a rare but aggressive type of cancer resistant to mitotane therapy. The intracellular calcium signaling pathway is one of the most important mechanisms for cells. The effect of intracellular calcium concentration [(Ca2+i)] on the function of cancer cells is also known. CaN, activated by the binding of calmodulin and Ca2+, is critical in this pathway. Methods: H295 adrenocortical cancer cells were treated with mitotane, cyclosporine A (CsA), and a combination of both. Cell viability, apoptosis, cell cycle, and gene expression levels of apoptosis-related genes (BCL2, BAX, TP53) were analyzed. Western blotting was used to measure CaN protein levels, and wound healing assays assessed cell migration. Results: CsA significantly suppressed CaN protein levels in a dose-dependent manner, reducing cell viability and increasing apoptosis in H295 cells. Mitotane alone also suppressed CaN protein, but the combination of mitotane and CsA had a synergistic effect, further decreasing cell viability and increasing apoptosis. The combination treatment led to significant suppression of the BCL2 gene and upregulation of TP53. Cell cycle analysis showed increased arrest in the G0/G1 phase with combination treatment. Conclusion: Suppression of CaN by CsA enhances the cytotoxic effects of mitotane on ACC cells, suggesting a potential therapeutic strategy to improve ACC treatment outcomes. This study highlights the importance of targeting intracellular calcium signaling pathways to overcome resistance and enhance the efficacy of existing cancer therapies.

Significance of Ribonucleoside-diphosphate Reductase Subunit M2 in Lung Adenocarcinoma.

The Ribonucleoside-diphosphate Reductase subunit M2 (RRM2) is known to be overexpressed in various cancers, though its specific functional implications remain unclear. This aims to elucidate the role of RRM2 in the progression of Lung Adenocarcinoma (LUAD) by exploring its involvement and potential impact. RRM2 data were sourced from multiple databases to assess its diagnostic and prognostic significance in LUAD. We evaluated the association between RRM2 expression and immune cell infiltration, analyzed its function, and explored the effects of modulating RRM2 expression on LUAD cell characteristics through laboratory experiments. RRM2 was significantly upregulated in LUAD tissues and cells compared to normal counterparts (p<0.05), with rare genetic alterations noted (approximately 2%). This overexpression clearly distinguished LUAD from normal tissue (area under the curve (AUC): 0.963, 95% confidence intervals (CI): 0.946-0.981). Elevated RRM2 expression was significantly associated with adverse clinicopathological characteristics and poor prognosis in LUAD patients. Furthermore, a positive association was observed between RRM2 expression and immune cell infiltration. Pathway analysis revealed a critical connection between RRM2 and the cell cycle signaling pathway within LUAD. Targeting RRM2 inhibition effectively suppressed LUAD cell proliferation, migration, and invasion while promoting apoptosis. This intervention also modified the expression of several crucial proteins, including the downregulation of CDC25A, CDC25C, RAD1, Bcl-2, and PPM1D and the upregulation of TP53 and Bax (p < 0.05). Our findings highlight the potential utility of RRM2 expression as a biomarker for diagnosing and predicting prognosis in LUAD, shedding new light on the role of RRM2 in this malignancy.

A New Benzo[6,7]oxepino[3,2-b] Pyridine Derivative Induces Apoptosis in Canine Mammary Cancer Cell Lines

CMC is the most frequently diagnosed cancer and one of the leading causes of death in non-spayed female dogs. Exploring novel therapeutic agents is necessary to increase the survival rate of dogs with CMC. MPOBA is a BZOP derivative that has a significant anticancer effect in a human cell line. The main goal of this study was to investigate the anticancer properties of MPOBA against two CMC cell lines (REM134 and CMGT071020) using a 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, a wound healing assay, a transwell migration assay, an Annexin V-FITC apoptosis assay with a flow cytometry analysis, a mRNA expression analysis using quantitative real-time PCR (qRT-PCR), and an immunohistochemistry (IHC). According to the accumulated studies, MPOBA caused significant concentration- and time-dependent reductions in cell proliferation and cell migration and induced apoptosis in both CMC cell lines. In gene expression analysis, nine canine genes, including TP53, BCL-2, BAX, epidermal growth factor receptor (EGFR), snail transcription factor (SNAIL), snail-related zinc-finger transcription factor (SLUG), TWIST, E-cadherin, and N-cadherin, were investigated. The mRNA expression results revealed that MPOBA induced upregulation of TP53 and overexpression of the pro-apoptotic gene BAX, together with an inhibition of BCL-2. Moreover, MPOBA also suppressed the mRNA expression levels of SNAIL, EGFR, and N-cadherin and induced upregulation of E-cadherin, crucial genes related to the epithelial-to-mesenchymal transition (EMT). However, there was no significant difference in the IHC results of the expression patterns of vimentin (VT) and cytokeratin (CK) between MPOBA-treated and control CMC cells. In conclusion, the results of the present study suggested that MPOBA exhibited significant anticancer activity by inducing apoptosis in both CMCs via upregulation of TP53 and BAX and downregulation of BCL-2 relative mRNA expression. MPOBA may prove to be a potential candidate drug to be further investigated as a therapeutic agent for CMC.

Assessment of SIRT1-SIRT7 and TP53 Genes Expression in Patients with Acute Myeloid Leukemia

BACKGROUND Sirtuins ( SIRTs) are a family of histone deacetylases with 7 representatives ( SIRT1-7), which affect cell survival and metabolism. They influence gene expression by interacting with histones and transcription factors, or directly modulate pathways associated with cell survival, for instance by downregulating p53, thus potentially contributing to cancerogenesis. On the other hand, SIRTs may function as tumor suppressors depending on cellular context. While the role of SIRTs expression is widely discussed in solid neoplasms, they have not been comprehensively evaluated in acute myeloid leukemia (AML) yet. AIMS To investigate the prognostic importance of initial SIRTs expression in AML patients (pts) and its relationship with the expression of TP53. METHODS The study included 40 newly diagnosed AML pts (19 women, 21 men), with a mean age of 62 years (range: 26-87). Low-, intermediate- or high-risk AML according to European LeukemiaNet (ELN) 2022 stratification was diagnosed in 6 (15%), 13 (32.5%), and 21 (52.5%) of pts respectively. The expression of SIRT1-7 and TP53 was examined by real-time PCR using the TaqMan chemistry and the QuantStudio7 thermal cycler (Applied Biosystems-Thermo Fisher Scientific). The reference genes were selected using GeNorm and NormFinder. The mRNA levels were normalized by the formula ∆Ct = Ct(reference) - Ct(particular mRNA). Group comparisons were performed using Welch's t-test. Pearson correlation evaluated the relationship between individual gene expression. Overall survival (OS) was assessed by the Kaplan-Meier method with the log-rank test. Cox proportional hazard regression of clinical factors and genes expression for predicting OS was performed. RESULTS FLT3 ITDor TKD mutations were present in 10 (25%) of pts, NPM1 in 9 (23%), and IDH1 or IDH2 in 6 (15%). 14 (35%) of the study group were diagnosed with AML with myelodysplasia-related cytogenetic abnormalities, AML progressed from myelodysplastic syndrome, or therapy-related AML (secondary AML, sAML). Standard induction chemotherapy was given in 42.5% of pts, 25% were treated with azacitidine+venetoclax (Aza+Ven), and other non-intensive therapies were administered to 32.5%. SIRT4 expression was detected in 92.5% of pts, while expression of the other genes studied was found in all pts. There were no differences in SIRT 1-7 expression in terms of ELN2022 risk stratification. However, TP53 was downregulated in the high-risk group (fold change - FC=0.6, p=0.004). In pts with FLT3 mutation, SIRT7 was downregulated (FC=0.8, p=0.07), while in both NPM1 and IDH1/2 mutated groups, we showed upregulation of TP53 (FC=1.5, p=0.03, and FC=1.5, p=0.001, respectively). Moreover, in older pts (&amp;gt;60 years old) TP53 was downregulated (FC=0.7, p=0.02). In sAML group SIRT3 and TP53 were downregulated (FC=0.7, p=0.08, and FC=0.7, p=0.05, respectively). Significant positive correlations were shown between the expression of individual SIRTs, and it was most strongly expressed between SIRT2 and SIRT6 (r=0.85, p=0.00), SIRT2 and SIRT7 (r=0.81, p=0.00), and SIRT6 and SIRT7 (r=0.76, p=0.00). The median follow-up was 6.7 months (95% CI: 4.5-9.1). The median OS in the study cohort was not reached. There were no significant differences in treatment response or OS considering each SIRT expression level. However, pts with higher TP53 expression (&amp;gt; median) presented longer OS (median OS not reached vs 5.8 months (95% CI:1.3-5.8, p=0.05) [Figure 1]. In the multivariate Cox proportional hazard model for OS, upregulation of TP53 (HR 0.25, 95%CI: 0.08-0.60, p=0.01), age (HR 1.06, 95%CI: 1.01-1.12, p=0.03), as well as initial albumins (HR 0.01, 95%CI: 0.00-0.07, p=0.01), and LDH levels (HR 1.00, 95%CI: 1.00-1.01, p=0.01) were factors influencing the outcome [Table 1]. CONCLUSIONS The expression of SIRTs in AML presented no evident impact on treatment outcome. However, our study revealed that higher TP53 expression was associated with longer OS. Moreover, TP53 upregulation was found in pts with certain mutational profiles, while downregulation in the elderly and those with sAML. The analysis indicates that SIRTs expression may also vary markedly depending on the clinical and molecular context. The expression of individual SIRTs is closely correlated with each other, but these preliminary results did not show their direct relationship with TP53 expression. Further studies on SIRTs are needed to assess their impact on AML.

Loss of EFL1 Which Causes a Shwachman-Diamond Syndrome Reduces Cell Proliferation and Alters Transcriptional Profiling during Neutrophil Differentiation

Introduction. Shwachman-Diamond syndrome (SDS) is an inherited bone marrow failure syndrome characterized by neutropenia, exocrine pancreatic insufficiency, and skeletal abnormalities. Patients with SDS are predisposed to develop myeloid malignancy. Almost all individuals with SDS harbor biallelic mutations in SBDS. The partner of SBDS is EFL1, a ribosomal protein with GTPase activity. More than a dozen patients have been found with SDS due to biallelic mutations in EFL1. EFL1 serves to release EIF6, facilitating the assembly of the 80S ribosome from 60S and 40S ribosome subunits. Our lab has generated both sbds and efl1 null zebrafish, which phenocopy much of the human syndrome. We recently reported that Sbds and Efl1 depletion leads to upregulation of tp53 and cdkn1a ( p21) and accumulation of Eif6 in SDS zebrafish models, which is hypothesized to cause bone marrow failure. However, the mechanism(s) of EFL1's loss-of-function leading to neutropenia is not known. Methods. We used CRISPR/Cas9 editing to generate mutations in exon 17 of Efl1 of 32Dcl3, an IL-3-dependent murine myeloid cell line that can be differentiated to mature neutrophils. We analyzed the effects of Efl1 mutations on cell proliferation, survival, and differentiation with G-CSF. Immunoblotting and qPCR-based gene expression analysis were performed to identify affected mechanistic pathways. Results. Two clones were isolated and were sequenced to verify biallelic deleterious mutations. A clone with compound heterozygous inframe deletion and frameshift mutations showed trace expression of EFL1 (EFL1-KD) and the other with compound heterozygous frameshift mutations showed no expression (EFL1-KO). They presented a myeloblast-like morphology indistinguishable from parental cells. They proliferated significantly less than parental cells, although there was no increased apoptosis. Both EFL1-KD and KO cells showed significantly increased protein expression of EIF6 and transcriptional expression of Trp53 and Cdkn1a. EFL1 was downregulated during differentiation of parental 32Dcl3 cells to neutrophils, whereas EIF6 levels did not change. Withdrawal and replenishment of IL-3 from culturing media did not alter EFL1 protein expression. When EFL1-KD and KO were cultured in differentiating media, they did not proliferate and underwent greater apoptosis, particularly after 3 days of differentiation compared to parental 32Dcl3. The surviving EFL1-KD and KO matured into neutrophils after 7 days. Gene profiling for neutrophil differentiation identified equivalent expression of key transcriptional factors ( Cebpa, Cebpe, and Spi1) of EFL1-KD and KO in the maintenance media, except for Gfi1 which was two-fold and three-fold high in EFL1-KD and KO compared to parental cells, respectively. G-CSF induced significantly higher expression of Cebpa and lower expression of Cebpe in EFL1-KO from those in parental cells, respectively. Based on the observation that somatic genetic rescue by EIF6 mutations occurs in human SDS patients and animal models, we transfected 32Dcl3 cells with siRNA against Eif6. In parental 32Dcl3 cells, reduction of EIF6 caused slow cell growth; however, transfection of siRNA to Eif6 partially rescued proliferation of EFL1-KD and KO in both maintenance and differentiating media. Conclusions. Our results suggested that imbalance of late maturing factors of ribosome associated with SDS may cause decreased proliferation in myeloid-committed cells, thereby leading to neutropenia in SDS. Newly established Efl1-deficient cells recapitulated key observation from SDS patients, with an increased proapoptotic profile in hematopoietic cells. Because EFL1 has only been recognized recently as a rare cause of SDS, we do not know if EFL1 deficiency serves as a leukemia predisposition syndrome. We speculate that the aberrant normal neutrophil differentiation may form the foundation for myeloid neoplasia in SDS.

Enhanced Transcriptional Signature and Expression of Histone-Modifying Enzymes in Salivary Gland Tumors.

Salivary gland tumors (SGTs) are rare and complex neoplasms characterized by heterogenous histology and clinical behavior as well as resistance to systemic therapy. Tumor etiology is currently under elucidation and an interplay of genetic and epigenetic changes has been proposed to contribute to tumor development. In this work, we investigated epigenetic regulators and histone-modifying factors that may alter gene expression and participate in the pathogenesis of SGT neoplasms. We performed a detailed bioinformatic analysis on a publicly available RNA-seq dataset of 94 ACC tissues supplemented with clinical data and respective controls and generated a protein-protein interaction (PPI) network of chromatin and histone modification factors. A significant upregulation of TP53 and histone-modifying enzymes SUV39H1, EZH2, PRMT1, HDAC8, and KDM5B, along with the upregulation of DNA methyltransferase DNMT3A and ubiquitin ligase UHRF1 mRNA levels, as well as a downregulation of lysine acetyltransferase KAT2B levels, were detected in ACC tissues. The protein expression of p53, SUV39H1, EZH2, and HDAC8 was further validated in SGT tissues along with their functional deposition of the repressive histone marks H3K9me3 and H3K27me3, respectively. Overall, this study is the first to detect a network of interacting proteins affecting chromatin structure and histone modifications in salivary gland tumor cells, further providing mechanistic insights in the molecular profile of SGTs that confer to altered gene expression programs.

TP53 Induced Glycolysis and Apoptosis Regulator and Monocarboxylate Transporter 4 drive metabolic reprogramming with c-MYC and NFkB activation in breast cancer.

Breast cancer is composed of metabolically coupled cellular compartments with upregulation of TP53 Induced Glycolysis and Apoptosis Regulator (TIGAR) in carcinoma cells and loss of caveolin 1 (CAV1) with upregulation of monocarboxylate transporter 4 (MCT4) in fibroblasts. The mechanisms that drive metabolic coupling are poorly characterized. The effects of TIGAR on fibroblast CAV1 and MCT4 expression and breast cancer aggressiveness was studied using coculture and conditioned media systems and in-vivo. Also, the role of cytokines in promoting tumor metabolic coupling via MCT4 on cancer aggressiveness was studied. TIGAR downregulation in breast carcinoma cells reduces tumor growth. TIGAR overexpression in carcinoma cells drives MCT4 expression and NFkB activation in fibroblasts. IL6 and TGFB drive TIGAR upregulation in carcinoma cells, reduce CAV1 and increase MCT4 expression in fibroblasts. Tumor growth is abrogated in the presence of MCT4 knockout fibroblasts and environment. We discovered coregulation of c-MYC and TIGAR in carcinoma cells driven by lactate. Metabolic coupling primes the tumor microenvironment allowing for production, uptake and utilization of lactate. In sum, aggressive breast cancer is dependent on metabolic coupling.

Oxidative stress induced by Pollonein-LAAO, a new L-amino acid oxidase from Bothrops moojeni venom, prompts prostate tumor spheroid cell death and impairs the cellular invasion process in vitro

Cancer cells produce abnormal levels of reactive oxygen species (ROS) that contribute to promote their malignant phenotype. In this framework, we hypothesized that the change in ROS concentration above threshold could impair key events of prostate cancer cells (PC-3) progression. Our results demonstrated that Pollonein-LAAO, a new L-amino acid oxidase obtained from Bothrops moojeni venom, was cytotoxic to PC-3 cells in two-dimensional and in tumor spheroid assays. Pollonein-LAAO was able to increase the intracellular ROS generation that culminates in cell death from apoptosis by both intrinsic and extrinsic pathways due to the up-regulation of TP53, BAX, BAD, TNFRSF10B and CASP8. Additionally, Pollonein-LAAO reduced mitochondrial membrane potential and caused G0/G1 phase to delay, due to the up-regulation of CDKN1A and the down-regulation of the expression of CDK2 and E2F. Interestingly, Pollonein-LAAO inhibited critical steps of the cellular invasion process (migration, invasion and adhesion), due to the down-regulation of SNAI1, VIM, MMP2, ITGA2, ITGAV and ITGB3. Furthermore, the Pollonein-LAAO effects were associated with the intracellular ROS production, since the presence of catalase restored the invasiveness of PC-3 cells. In this sense, this study contributes to the potential use of Pollonein-LAAO as ROS-based agent to enhance the current understanding of cancer treatment strategies.

Mechanism exploration of 6-Gingerol in the treatment of atherosclerosis based on network pharmacology, molecular docking and experimental validation

BackgroundThe 6-Gingerol has significant anti-inflammatory, anti-oxidative and hypolipidemic activities and is widely used for treating cardiac-cerebral vascular diseases. However, the multi-target mechanism of 6-Gingerol in the treatment of atherosclerosis remains to be elucidated. MethodsFirstly, the therapeutic actions of 6-Gingerol anti-atherosclerosis were researched based on an atherosclerotic ApoE-deficient mice model induced by high-fat feed. Then, network pharmacology and molecular docking were employed to reveal the anti-atherogenic mechanism of 6-Gingerol. Finally, the target for these predictions was validated by target protein expression assay in vitro and in vivo experiments and further correlation analysis. ResultsFirstly, 6-Gingerol possessed obvious anti-atherogenic activity, which was manifested by a significant reduction in the plaque area, decrease in the atherosclerosis index and vulnerability index. Secondly, based on network pharmacology, 14 predicted intersection target genes between the targets of 6-Gingerol and atherogenic-related targets were identified. The key core targets of 6-Gingerol anti-atherosclerosis were found to be TP53, RELA, BAX, BCL2, and CASP3. Lipid and atherosclerosis pathways might play a critical role in 6-Gingerol anti-atherosclerosis. Molecular docking results also further revealed that the 6-Gingerol bound well and stable to key core targets from network pharmacological predictions. Then, the experimental results in vivo and in vitro verified that the up-regulation of TP53, RELA, BAX, CASP3, and down-regulation of BCL2 from atherosclerotic ApoE-deficient mice model can be improved by 6-Gingerol intervention. Meanwhile, the correlation analysis further confirmed that 6-Gingerol anti-atherosclerosis was closely related to these targets. ConclusionThe 6-Gingerol can markedly improve atherosclerosis by modulating key multi-targets TP53, RELA, BAX, CASP3, and BCL2 in lipid and atherosclerosis pathways. These novel findings shed light on the anti-atherosclerosis mechanism of 6-Gingerol from the perspective of multiple targets and pathways.

Characterization of proteome-size scaling by integrative omics reveals mechanisms of proliferation control in cancer.

Almost all living cells maintain size uniformity through successive divisions. Proteins that over and underscale with size can act as rheostats, which regulate cell cycle progression. Using a multiomic strategy, we leveraged the heterogeneity of melanoma cell lines to identify peptides, transcripts, and phosphorylation events that differentially scale with cell size. Subscaling proteins are enriched in regulators of the DNA damage response and cell cycle progression, whereas super-scaling proteins included regulators of the cytoskeleton, extracellular matrix, and inflammatory response. Mathematical modeling suggested that decoupling growth and proliferative signaling may facilitate cell cycle entry over senescence in large cells when mitogenic signaling is decreased. Regression analysis reveals that up-regulation of TP53 or CDKN1A/p21CIP1 is characteristic of proliferative cancer cells with senescent-like sizes/proteomes. This study provides one of the first demonstrations of size-scaling phenomena in cancer and how morphology influences the chemistry of the cell.

A t(4;13)(q21;q14) translocation in B-cell chronic lymphocytic leukemia causing concomitant homozygous DLEU2/miR15a/miR16-1 and heterozygous ARHGAP24 deletions

13q14 deletion is the most recurrent chromosomal aberration reported in B-CLL, having a favorable prognostic significance when occurring as the sole cytogenetic alteration. However, its clinical outcome is also related to the deletion size and number of cells with the del(13)(q14) deletion. In 10% of cases, 13q14 deletion arises following a translocation event with multiple partner chromosomes, whose oncogenic impact has not been investigated so far due to the assumption of a possible role as a passenger mutation.Here, we describe a t(4;13)(q21;q14) translocation occurring in a B-CLL case from the diagnosis to spontaneous regression. FISH and SNP-array analyses revealed a heterozygous deletion at 4q21, leading to the loss of the Rho GTPase Activating Protein 24 (ARHGAP24) tumor suppressor gene, down-regulated in the patient RNA, in addition to the homozygous deletion at 13q14 involving DLEU2/miR15a/miR16–1 genes. Interestingly, targeted Next Generation Sequencing analysis of 54 genes related to B-CLL indicated no additional somatic mutation in the patient, underlining the relevance of this t(4;13)(q21;q14) aberration in the leukemogenic process.In all tested RNA samples, RT-qPCR experiments assessed the downregulation of the PCNA, MKI67, and TOP2A proliferation factor genes, and the BCL2 anti-apoptotic gene as well as the up-regulation of TP53 and CDKN1A tumor suppressors, indicating a low proliferation potential of the cells harboring the aberration. In addition, RNA-seq analyses identified four chimeric transcripts (ATG4B::PTMA, OAZ1::PTMA, ZFP36::PTMA, and PIM3::BRD1), two of which (ATG4B::PTMA and ZFP36::PTMA) failed to be detected at the remission, suggesting a possible transcriptional remodeling during the disease course. Overall, our results indicate a favorable prognostic impact of the described chromosomal aberration, as it arises a permissive molecular landscape to the spontaneous B-CLL regression in the patient, highlighting ARHGAP24 as a potentially relevant concurrent alteration to the 13q14 deletion in delineating B-CLL disease evolution.

Mutation and up-regulation of TP53 in ovine pulmonary adenocarcinoma lung cells as a model of human lung cancer.

Ovine pulmonary adenocarcinoma (OPA) is a model of human lung cancer‎ and fatal viral disease that causes neoplasia in sheep respiratory cells. ‎In the current study, 986 lung samples was inspected in the slaughterhouse, and finally twenty OPA ‎ lung organs were clinically diagnosed and five healthy lung organs were assigned as the control sample. Three SSCP patterns were detected for the affected lungs animals in comparison with the healthy lungs. In addition, sequencing results indicated three different single point mutations in exon 4 of TP53 within infected lungs, whereas no mutations were observed in exon 9 of this gene. Real-time PCR results showed up-regulation of the TP53 gene in all the infected lung cells compared to healthy cells. There was significant correlation between the mutations in exon 4 and OPAand can be used as a useful tool in determining the mechanism of lung cancer.

FOXL2 and FOXA1 cooperatively assemble on the TP53 promoter in alternative dimer configurations.

Although both the p53 and forkhead box (FOX) family proteins are key transcription factors associated with cancer progression, their direct relationship is unknown. Here, we found that FOX family proteins bind to the non-canonical homotypic cluster of the p53 promoter region (TP53). Analysis of crystal structures of FOX proteins (FOXL2 and FOXA1) bound to the p53 homotypic cluster indicated that they interact with a 2:1 stoichiometry accommodated by FOX-induced DNA allostery. In particular, FOX proteins exhibited distinct dimerization patterns in recognition of the same p53-DNA; dimer formation of FOXA1 involved protein–protein interaction, but FOXL2 did not. Biochemical and biological functional analyses confirmed the cooperative binding of FOX proteins to the TP53 promoter for the transcriptional activation of TP53. In addition, up-regulation of TP53 was necessary for FOX proteins to exhibit anti-proliferative activity in cancer cells. These analyses reveal the presence of a discrete characteristic within FOX family proteins in which FOX proteins regulate the transcription activity of the p53 tumor suppressor via cooperative binding to the TP53 promoter in alternative dimer configurations.

598 A novel curcumin-harmine-isovanillin compound inhibits the growth of actinic keratoses by suppressing MAPK and PI3K-AKT signaling

Actinic keratoses (AK) are premalignant cutaneous lesions with limited treatment options. Here we investigate GZ21T, a novel anti-tumor agent composed of curcumin, harmine, and isovanillin, in the treatment of AK. The pro-apoptotic effects of GZ21T on EGF-stimulated HaCaT cells were assessed by Annexin-V assay, and the mechanism was clarified by western blot. Treated cells were subjected to RNA-sequencing and reverse phase protein array. Differentially expressed genes (DEGs) were calculated using DESeq2 for R. Gene set enrichment analysis (GSEA) was performed using fgsea for R, and gene set variation analysis (GSVA) was conducted to evaluate GZ21T’s effect on pathways implicated in the pathogenesis of AK. Enrichment analysis was conducted on hypophosphorylated proteins using Enrichr. SKH-1 mice were exposed to UVB (500 J/m2) five times weekly for ten weeks and were subsequently treated with 0.25 grams topical GZ21T or control cream five days per week. An increase in the percentage of HaCaT cells in early (p=0.041) and late apoptosis (p=0.029) was observed with increasing GZ21T concentrations, which was partially mediated by PARP cleavage. After 40 days, GZ21T treated mice showed decreased lesion count (p=0.028) and tumor surface area (p=0.026). We identified 92 DEGs between control and GZ21T treated HacaT cells, with upregulation of TP53 and NOTCH1 tumor-suppressor genes. GSEA showed that GZ21T downregulates KRAS and mTOR signaling. GSVA revealed upregulation of transforming growth factor-beta (TGF-β) secretion and NOTCH signaling with downregulation of MAPK1 and 3 activation (p<0.05 for all). Proteomic analysis demonstrated downregulation of ErbB, mTOR, HIF-1, and PI3K-AKT signaling. In conclusion, GZ21T inhibits the growth of AK through suppression of targets related to MAPK, PI3K-AKT, HIF-1, and mTOR signaling.

Abstract 4030: Efficacy of novel combination therapy against AML cells with mutant NPM1

Abstract Cytoplasmic dislocation and loss of nucleolar localization of the chaperone protein NPM1c occurs in 30% of AML following a frame shift C-terminal mutation in exon 12 of NPM1 (creating NPM1c), which contributes to differentiation arrest, growth and survival of AML stem progenitor cells. In present studies, we determined that knock out (KO) of mutant (mt) NPM1 (NPM1c) in the AML OCI-AML3, utilizing targeted gRNA (compared to control) and CRISPR-Cas9, induced growth arrest, morphologic differentiation and loss of viability of the KO cells over 5 to 9 days. This was associated with depletion of protein levels of NPM1c, c-Myc, and MEIS1, but upregulation of PU.1, RUNX1, CD11b, p21 and NOXA levels. ChIP-Seq analysis with H3K27Ac antibody 5d after KO demonstrated reduced peak density at the super-enhancers of MYC, MEIS1, and HOXA9. RNA-Seq analysis showed negative enrichment of HALLMARK gene sets of mRNA expression of MEIS1/HOXA9, MYC targets, ribosome/translation and cell cycle. Compared to OCI-AML3 with NPM1c, OCI-AML3 with NPM1 KO exhibited abrogation of the Menin inhibitor SNDX-50469-induced differentiation and apoptosis. Additionally, NPM1 KO also significantly reduced sensitivity of OCI-AML3 cells to apoptosis induced by targeted agents previously shown to demonstrate efficacy against AML cells with NPM1c, including KPT-330 (XPO1 inhibitor), homoharringtonine (protein translation inhibitor), and anti-AML chemotherapeutic agents, including daunorubicin, cytarabine and etoposide. However, NPM1 KO sensitized OCI-AML3 cells to ATRA (all trans retinoic acid)-induced differentiation and loss of viability, which was associated with marked induction of p21 and CD11b. Utilizing RNA-Seq signature of NPM1c KO and interrogating the LINCS1000-CMap data set of gene expression signatures, we determined that among the top expression mimickers were several pan-HDAC inhibitors and a WEE1 kinase inhibitor. Treatment with adavosertib (WEE1 inhibitor, MK-1775) or romidepsin (HDAC inhibitor) dose-dependently induced apoptosis in OCI-AML3 cells, as well as in 5 samples of patient-derived (PD) AML cells with NPM1c. Moreover, co-treatment with adavosertib and romidepsin synergistically induced lethality in OCI-AML3 and PD AML cells with NPM1c. This was associated with marked reduction in protein expressions of c-Myc, c-Myb, MEIS1 and CDK4/6, but upregulation of TP53 and p21 levels. These findings highlight that presence of NPM1c mechanistically regulates the sensitivity of AML cells to Menin inhibitor, ATRA and anti-AML chemotherapeutic agents. They also identify the novel non-chemotherapy combination of pan-HDAC inhibitor and WEE1 inhibitor for its potential synergistic activity against AML with NPM1c. Citation Format: Christopher P. Mill, Warren C. Fiskus, John A. Davis, Courtney D. DiNardo, Christine Birdwell, Qi Jin, Koichi Takahashi, Joseph D. Khoury, Kapil N. Bhalla. Efficacy of novel combination therapy against AML cells with mutant NPM1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4030.

Fe3O4 nanoparticles coated with carboxymethyl chitosan containing curcumin in combination with hyperthermia induced apoptosis in breast cancer cells

Many studies have demonstrated that curcumin has potential anticancer properties. This research aims to study the effect of iron (II, III) oxide (Fe3O4) nanoparticles coated with carboxymethyl chitosan containing curcumin combination with hyperthermia on breast cancer cells. Magnetic nanoparticles coated with carboxymethyl chitosan containing curcumin (MNP-CMC-CUR) were prepared and specified. MCF-7, MDA-MB-231, and human fibroblast cells were treated with free curcumin and MNP-CMC-CUR at concentrations of 0-60µM and at different time points. A combined therapy of MNP-CMC-CUR and hyperthermia was performed on MCF-7 cells. The cytotoxicity of curcumin and MNP-CMC-CUR combined with hyperthermia was assessed by MTT. The changes in TP53 and CASPASE3 gene expression were evaluated using real-time PCR. Both cell apoptosis and cell cycle were studied by Annexin/PI staining. The results of MTT showed that the IC50 amount of MNP-CMC-CUR has significantly decreased compared to free curcumin (p < 0.05) and MNP-CMC-CUR in combination with the hyperthermia, and significantly reducing the metabolic activity of the cells (p < 0.05). Real-time PCR results revealed the up-regulation of TP53 and CASPASE3 (p < 0.05). The combinational therapy-induced cell apoptosis (64.51%) and sub-G1 cell cycle were arrested in MCF-7 cells. Based on these observations, a combination of MNP-CMC-CUR with hyperthermia could inhibit the proliferation of MCF-7 cells.

Interfering with mitochondrial dynamics sensitizes glioblastoma multiforme to temozolomide chemotherapy.

Glioblastoma multiforme (GBM) is a primary tumour of the central nervous system (CNS) that exhibits the highest degree of malignancy. Radiotherapy and chemotherapy are essential to prolong the survival time of patients. However, clinical work has demonstrated that sensitivity of GBM to chemotherapy decreases with time. The phenomenon of multi‐drug resistance (MDR) reminds us that there may exist some fundamental mechanisms in the process of chemo‐resistance. We tried to explore the mechanism of GBM chemo‐resistance from the perspective of energy metabolism. First, we found that the oxidative phosphorylation (OXPHOS) level of SHG44 and U87 cells increased under TMZ treatment. In further studies, it was found that the expression of PINK1 and mitophagy flux downstream was downregulated in GBM cells, which were secondary to the upregulation of TP53 in tumour cells under TMZ treatment. At the same time, we examined the mitochondrial morphology in tumour cells and found that the size of mitochondria in tumour cells increased under the treatment of TMZ, which originated from the regulation of AMPK on the subcellular localization of Drp1 under the condition of unbalanced energy supply and demand in tumour cells. The accumulation of mitochondrial mass and the optimization of mitochondrial quality accounted for the increased oxidative phosphorylation, and interruption of the mitochondrial fusion process downregulated the efficiency of oxidative phosphorylation and sensitized GBM cells to TMZ, which was also confirmed in the in vivo experiment. What is more, interfering with this process is an innovative strategy to overcome the chemo‐resistance of GBM cells.

Development of an MDM2 Degrader for Treatment of Acute Leukemias

IntroductionAcute myeloid leukemias (AMLs) are characterized by suppressed cell death pathways which promote leukemic blast survival. TP53 acts as a tumor suppressor gene in AML and is found mutated or deleted in 10-15% of patients. In a majority of cases though, TP53 is wild-type. Other mechanisms including MDM2 over-expression lead to reduced TP53 activity. MDM2 acts as a negative regulator by direct binding of TP53 and mediating TP53 degradation through ubiquitination. MDM2 itself is a transcriptional target of TP53 as a negative feedback mechanism limiting the function of TP53. Small molecule inhibition of MDM2 , blocking its ability to bind TP53, can activate TP53 and trigger cell cycle arrest and apoptosis through increased transcription of TP53 target genes. Increased MDM2 expression has been observed in hematologic malignancies including AML, providing rationale for clinical trials with MDM2 inhibitors. These agents such as RG7388 and AMG232 have shown efficacy as monotherapy and in combination. However, these agents have also exhibited toxicity and have yet to demonstrate sufficient benefit for their approval. To create more effective agents against MDM2, we have developed an MDM2 degrader XY-27 that functions as a proteolysis-targeting chimera (PROTAC). Based on relatively higher expression in AML compared to other cancer types, we selected VHL as the E3 ubiquitin ligase target for XY-27 , as this may improve specificity and potency in AML.ResultsThe PROTAC degrader XY-27 concurrently binds MDM2 and VHL, and by bringing these targets in proximity, VHL can then ubiquitinate MDM2, leading to its degradation by the proteasome. XY-27 can mediate degradation of MDM2 in a concentration dependent manner in the U937 leukemia cell line (Fig 1a). MDM2 degradation with XY-27 is blocked by proteasome inhibition and competitive binding of the VHL ligand. A control compound, which only differs in that it cannot bind to VHL, lacks degrader activity. Although MDM2 is itself an E3 ligase, VHL expression is not appreciably changed with XY-27 (Fig 1a).Treatment with XY-27 leads to apoptosis and decreased proliferation of leukemia cell lines in a TP53 dependent manner. Inhibition of MDM2 leads to up-regulation of TP53 and in TP53 wild-type cells, downstream targets CDKN1A (p21) and PUMA. MDM2 is also up-regulated through a feedback mechanism. XY-27 demonstrated greater potency than the MDM2-binding inhibitor AMG232 in the MOLM13 and MV4-11 leukemia cell lines (Fig 1b). Treatment with XY-27 led to higher levels of TP53 and p21 protein than with AMG232. CRISPR-mediated knock-out of VHL leads to reduced XY-27 potency. XY-27 also shows efficacy when combined with other chemotherapeutic agents such as azacytidine and cytarabine. In a long-term co-culture model with an OP9 feeder layer, XY-27 was capable of inducing apoptosis in primary patient AML samples (Fig 1c).ConclusionWe describe a new MDM2 PROTAC, XY-27 that demonstrates TP53 dependent activity against leukemia cells. It also demonstrates increase potency compared to an MDM2 binding inhibitor. Utilization of the PROTAC system has potential advantages through selection of the VHL E3 ubiquitin ligase. Because of negative feedback mechanisms involving TP53 and MDM2, direct binding inhibitors of MDM2 may be limited in activity through continued accumulation of MDM2. PROTAC degraders have catalytic activity and may overcome this inhibition by continued degradation of the target MDM2, and thus achieve greater TP53 activity.Figure 1. Activity of the MDM2-PROTAC XY-27 in leukemia. (a) Western blot from treatment of U937 leukemia cells with XY-27 for 24 hrs, at various concentrations (5 nM to 1 μM), resulting in the degradation of MDM2. (b) Dose response curves from treatment of MOLM13 and MV4-11 cell lines with XY-27 (blue) and AMG232 (red) for 48 hrs, demonstrating greater potency of XY-27. (c) Induction of apoptosis in primary AML cells treated with XY-27 at 1μM using a co-culture system for 3 days. *p<.05 [Display omitted] DisclosuresHoffman: Protagonist Therapeutics, Inc.: Consultancy; AbbVie Inc.: Other: Data Safety Monitoring Board, Research Funding; Novartis: Other: Data Safety Monitoring Board, Research Funding; Kartos Therapeutics, Inc.: Research Funding.

Mutant TP53 prevents Telomere Shortening in Acute Myeloid Leukemia

BackgroundHigh telomerase activity represents a critical feature of hematopoietic stem cells. Excessive shortening of telomere length (TL) due to replicative stress may be - in analogy to many solid tumors - a hallmark of myeloid neoplasia (MN). Also, telomeric footprints in leukemic genomes may vary between various subtypes corresponding to the differentiation arrest at various stages of hematopoietic ontogeny or specific molecular defects. Critical TL shortening has been associated with genomic instability and accelerated acquisition of genomic lesions leading to a more aggressive phenotype. These processes have not been systematically studied in MN, especially AML.AimBy taking advantage of next-generation sequencing to assay both molecular features and TL within large cohorts of patients, we tested the hypothesis that TL shortening is excessive in highly proliferative MN, but that distinct invariant differences characterize genetic subtypes.MethodsOur cohort included AML (N=734), MDS (N=701), healthy controls (HC) (N=11) and PNH (N=102) serving as clonal non-malignant controls. All patients were diagnosed according to WHO standards before being subjected to transcriptome (WTS) and genome (WGS, 100x) sequencing. To retrieve TL characteristics and telomere repeat heterogeneity from WGS data, we used TelomereHunter (TH). In parallel, we performed C-Circle assays. Patients were annotated for clinical features and analyzed for genetic/transcriptomic patterns.ResultsFor a subset of patients for whom corresponding benign lymphocyte DNA was available a significant TL shortening in blasts vs control lymphocytes (A; P=.0023) was detected. While age correlation was established in controls, despite a trend, in MN age did not significantly affect TL (B) and thus subsequent comparisons were not adjusted for age. Next, we studied a cohort of patients with AML, MDS, PNH and HC and found that TL shortening was an overarching finding in AML, MDS and PNH as compared to HC (C). Since no matched DNA was available as reference, we examined the distribution of TL across different age cohorts, AML patients divided according to age cohorts harbored TL in a similar range (D, P=.057). Classic morphologic (E) or cytogenetic subtypes AML exhibited no difference. Similarly, no differences were found between high and low risk MDS patients (not shown). The variability of TL ranges suggested that there may be molecular factors which affect individual TL. When we compared TL grouped according to frequent mutations, only TP53 mutations were associated with longer TL (F, P<.0001). A significant positive correlation (G, P=.021) between TL and TP53 clonal burden was found; samples with the longest vs shortest TL showed significantly higher TP53 VAF (H, P=.0229). In analogy, the presence of multiple TP53 mutations (putative biallelic inactivation) showed longer TL than single hits but no association was found between the nature of mutations and TL (I, J, K). Availability of WTS data allowed us to assess the telomerase activity using the EXTEND score (ES) which has been shown to assess telomerase activity. Indeed, the ES was correlated with TL (L) and TP53 mutant status was associated with a higher ES compared to WT samples (M, P<.0001). Similarly, because of the compensatory upregulation of TP53 in mutant cases, we have also found that TP53 mRNA levels correlated with ES (N P<.0001). Another explanation of TL increase could be the occurrence of alternative lengthening (ALT). TH software allows for estimation of the abundance of specific telomeric repeats. Singleton analysis showed that increase in telomere repeats variants (TTTGGG, O, P=.003) was related to mutations in TP53 arguing against the involvement of ALT. The final confirmation that TL extension was not due to ALT was provided by C-Circle assays. When C-Circle assays were performed for samples with a high/low TL and mutant/WT TP53, none of the subgroups was identified as ALT + (P).ConclusionWe stipulate that TL measurements using NGS will be helpful to investigate pathophysiological features associated with TL shortening. Availability of therapies targeting the telomere machinery (Imetelstat) may offer an opportunity for personalized therapy beyond MPN, its current indication. It remains to be tested whether long TL associated with TP53 mutations can serve as marker of sensitivity or resistance to these agents. [Display omitted] DisclosuresHaferlach: MLL Munich Leukemia Laboratory: Other: Part ownership. Kern: MLL Munich Leukemia Laboratory: Other: Part ownership. Haferlach: MLL Munich Leukemia Laboratory: Other: Part ownership. Maciejewski: Regeneron: Consultancy; Bristol Myers Squibb/Celgene: Consultancy; Alexion: Consultancy; Novartis: Consultancy.