A single nucleotide polymorphism in the MDM2 promoter attenuates the p53 tumor suppressor pathway and accelerates tumor formation in humans

Genetic polymorphisms and platinum-induced hematological toxicity: a systematic review

Background

Platinum-based chemotherapy bring severe hematological toxicity that can lead to dose reduction or discontinuation of therapy. Genetic variations have been reported to influence the risk and extent of hematological toxicity; however, the results are controversial and a comprehensive overview is lacking. This systematic review aimed to identify genetic biomarkers of platinum-induced hematological toxicity.

Method

Pubmed, Embase and Web of science database were systematically reviewed for studies that evaluated the association of genetic variants and platinum-related hematological toxicity in tumor patients with no prior history of chemotherapy or radiation, published from inception to the 28th of January 2022. The studies should have specific toxicity scoring system as well as defined toxicity end-point. The quality of reporting was assessed using the Strengthening the Reporting of Genetic Association Studies (STREGA) checklist. Results were summarized using narrative synthesis.

Results

83 studies were eligible with over 682 single-nucleotide polymorphisms across 110 genes. The results are inconsistent and diverse with methodological issues including insufficient sample size, population stratification, various treatment schedule and toxicity end-point, and inappropriate statistics. 11 SNPs from 10 genes (ABCB1 rs1128503, GSTP1 rs1695, GSTM1 gene deletion, ERCC1 rs11615, ERCC1 rs3212986, ERCC2 rs238406, XPC rs2228001, XPCC1 rs25487, MTHFR rs1801133, MDM2 rs2279744, TP53 rs1042522) had consistent results in more than two independent populations. Among them, GSTP1 rs1695, ERCC1 rs11615, ERCC1 rs3212986, and XRCC1 rs25487 present the most promising results.

Conclusion

Even though the results are inconsistent and several methodological concerns exist, this systematic review identified several genetic variations that deserve validation in well-defined studies with larger sample size and robust methodology.

Systematic Review Registration

https://www.crd.york.ac.uk/, identifier CRD42021234164.

Genetic Variants in p53 Pathway Genes Affect Survival of Patients with HBV-Related Hepatocellular Carcinoma

Purpose

P53 is a suppressor gene closely related to carcinogenesis. However, the associations between genetic variants in the p53 signaling pathway and prognosis in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) remain unknown. The current study aims to analyze associations between the single nucleotide polymorphisms (SNPs) in p53 pathway-related genes and survival of patients with HBV-HCC.

Methods

We evaluated the associations between 4698 SNPs in 70 genes of the p53 pathway and overall survival (OS) of 866 patients in additive genetic models by using Cox proportional hazards regression analysis. Stepwise multivariable Cox regression analysis was conducted to determine the independent effects of identified SNPs in single-locus analyses. The expression of quantitative trait loci (eQTL) was also analyzed using data from GTEx and 1000 Genomes Project, and functional prediction of SNPs was performed by using RegulomeDB v2.2, 3DSNP v2.0, HaploReg v4.2 and VannoPortal.

Results

We found that two novel SNPs of CD82 rs7925603 A > G and PMAIP1 rs4396625 A > T, were significantly and independently associated with OS [adjusted hazards ratios (HRs) and 95% confidence intervals (CI) were 1.27 (1.10-1.48) and 0.77 (0.66-0.91), respectively; P = 0.001 and = 0.002, respectively] and that the combined risk genotypes of these SNPs showed a significant association with OS in patients with HBV-HCC (P trend < 0.001). Further eQTL analysis in the GTEx dataset showed that the rs7925603 G allele was associated with lower CD82 mRNA expression levels, while the rs4396625 T allele was associated with higher PMAIP1 mRNA expression levels in whole blood cells.

Conclusion

We identified two observed survival-associated SNPs in CD82 and PMAIP1 in the p53 pathway, which influenced HBV-HCC survival possibly through a mechanism of altering mRNA expression. Large studies are warranted to validate our findings.

Whole-exome sequencing reveals novel cancer genes and actionable targets in biliary tract cancers in primary sclerosing cholangitis

BACKGROUND

People with primary sclerosing cholangitis (PSC) have a 20% lifetime risk of biliary tract cancer (BTC). Using whole-exome sequencing, we characterized genomic alterations in tissue samples from BTC with underlying PSC.

METHODS

We extracted DNA from formalin-fixed, paraffin-embedded tumor and paired nontumor tissue from 52 resection or biopsy specimens from patients with PSC and BTC and performed whole-exome sequencing. Following copy number analysis, variant calling, and filtering, putative PSC-BTC-associated genes were assessed by pathway analyses and annotated to targeted cancer therapies.

RESULTS

We identified 53 candidate cancer genes with a total of 123 nonsynonymous alterations passing filtering thresholds in 2 or more samples. Of the identified genes, 19% had not previously been implicated in BTC, including CNGA3, KRT28, and EFCAB5. Another subset comprised genes previously implicated in hepato-pancreato-biliary cancer, such as ARID2, ELF3, and PTPRD. Finally, we identified a subset of genes implicated in a wide range of cancers such as the tumor suppressor genes TP53, CDKN2A, SMAD4, and RNF43 and the oncogenes KRAS, ERBB2, and BRAF. Focal copy number variations were found in 51.9% of the samples. Alterations in potential actionable genes, including ERBB2, MDM2, and FGFR3 were identified and alterations in the RTK/RAS (p = 0.036), TP53 (p = 0.04), and PI3K (p = 0.043) pathways were significantly associated with reduced overall survival.

CONCLUSIONS

In this exome-wide characterization of PSC-associated BTC, we delineated both PSC-specific and universal cancer genes. Our findings provide opportunities for a better understanding of the development of BTC in PSC and could be used as a platform to develop personalized treatment approaches.

Hidden secrets of the cancer genome: unlocking the impact of non-coding mutations in gene regulatory elements

Discoveries in the field of genomics have revealed that non-coding genomic regions are not merely "junk DNA", but rather comprise critical elements involved in gene expression. These gene regulatory elements (GREs) include enhancers, insulators, silencers, and gene promoters. Notably, new evidence shows how mutations within these regions substantially influence gene expression programs, especially in the context of cancer. Advances in high-throughput sequencing technologies have accelerated the identification of somatic and germline single nucleotide mutations in non-coding genomic regions. This review provides an overview of somatic and germline non-coding single nucleotide alterations affecting transcription factor binding sites in GREs, specifically involved in cancer biology. It also summarizes the technologies available for exploring GREs and the challenges associated with studying and characterizing non-coding single nucleotide mutations. Understanding the role of GRE alterations in cancer is essential for improving diagnostic and prognostic capabilities in the precision medicine era, leading to enhanced patient-centered clinical outcomes.

Understanding the complexity of p53 in a new era of tumor suppression

p53 was discovered 45 years ago as an SV40 large T antigen binding protein, coded by the most frequently mutated TP53 gene in human cancers. As a transcription factor, p53 is tightly regulated by a rich network of post-translational modifications to execute its diverse functions in tumor suppression. Although early studies established p53-mediated cell-cycle arrest, apoptosis, and senescence as the classic barriers in cancer development, a growing number of new functions of p53 have been discovered and the scope of p53-mediated anti-tumor activity is largely expanded. Here, we review the complexity of different layers of p53 regulation, and the recent advance of the p53 pathway in metabolism, ferroptosis, immunity, and others that contribute to tumor suppression. We also discuss the challenge regarding how to activate p53 function specifically effective in inhibiting tumor growth without harming normal homeostasis for cancer therapy.

Age-specific induction of mutant p53 drives clonal hematopoiesis and acute myeloid leukemia in adult mice

The investigation of the mechanisms behind p53 mutations in acute myeloid leukemia (AML) has been limited by the lack of suitable mouse models, which historically have resulted in lymphoma rather than leukemia. This study introduces two new AML mouse models. One model induces mutant p53 and Mdm2 haploinsufficiency in early development, showing the role of Mdm2 in myeloid-biased hematopoiesis and AML predisposition, independent of p53. The second model mimics clonal hematopoiesis by inducing mutant p53 in adult hematopoietic stem cells, demonstrating that the timing of p53 mutation determines AML vs. lymphoma development. In this context, age-related changes in hematopoietic stem cells (HSCs) collaborate with mutant p53 to predispose toward myeloid transformation rather than lymphoma development. Our study unveils new insights into the cooperative impact of HSC age, Trp53 mutations, and Mdm2 haploinsufficiency on clonal hematopoiesis and the development of myeloid malignancies.

Genetic variability profiling of the p53 signaling pathway in chronic lymphocytic leukemia. Individual and combined analysis of TP53, MDM2 and NQO1 gene variants

TP53 gene disruption, including 17p13 deletion [del(17p)] and/or TP53 mutations, is a negative prognostic biomarker in chronic lymphocytic leukemia (CLL) associated with disease progression, treatment failure and shorter survival. Germline variants in p53 signaling pathway genes could also lead to p53 dysfunction, but their involvement in CLL has not been thoroughly evaluated. The aim of this study was to determine the association of TP53, MDM2 and NQO1 gene variability with clinical and genetic data of CLL patients. Individual genotype and haplotype data of CLL patients were compared with clinical prognostic factors, cytogenetic and molecular cytogenetic findings as well as IGHV and TP53 mutational status. The study included 116 CLL patients and 161 healthy blood donors. TP53 (rs1042522, rs59758982, rs1625895), NQO1 (rs1800566) and MDM2 (rs2279744, rs150550023) variants were genotyped using different PCR approaches. Analysis of genotype frequencies revealed no association with the risk of CLL. TP53 rs1042522, rs1625895 and MDM2 rs2279744 variants were significantly associated with abnormal karyotype and the presence of del(17p). Similarly, these two TP53 variants were associated with TP53 disruption. Moreover, TP53 C-A-nondel and G-A-del haplotypes (rs1042522-rs1625895-rs59758982) were associated with an increased likelihood of carrying del(17p) and TP53 disruptions. MDM2 T-nondel haplotype (rs2279744-rs150550023) was found to be a low risk factor for del(17p) (OR = 0.32; CI: 0.12-0.82; p = 0.02) and TP53 disruptions (OR = 0.41; CI: 0.18-0.95; p = 0.04). Our findings suggest that TP53 and MDM2 variants may modulate the risk to have chromosome alterations and TP53 disruptions, particularly del(17p). To our knowledge this is the first study of several germline variants in p53 pathway genes in Argentine patients with CLL.

Genetics of ischemic stroke functional outcome

Ischemic stroke, which accounts for 87% of cerebrovascular accidents, is responsible for massive global burden both in terms of economic cost and personal hardship. Many stroke survivors face long-term disability-a phenotype associated with an increasing number of genetic variants. While clinical variables such as stroke severity greatly impact recovery, genetic polymorphisms linked to functional outcome may offer physicians a unique opportunity to deliver personalized care based on their patient's genetic makeup, leading to improved outcomes. A comprehensive catalogue of the variants at play is required for such an approach. In this review, we compile and describe the polymorphisms associated with outcome scores such as modified Rankin Scale and Barthel Index. Our search identified 74 known genetic polymorphisms spread across 48 features associated with various poststroke disability metrics. The known variants span diverse biological systems and are related to inflammation, vascular homeostasis, growth factors, metabolism, the p53 regulatory pathway, and mitochondrial variation. Understanding how these variants influence functional outcome may be helpful in maximizing poststroke recovery.

A CANCER PERSISTENT DNA REPAIR CIRCUIT DRIVEN BY MDM2, MDM4 (MDMX), AND MUTANT P53 FOR RECRUITMENT OF MDC1 AND 53BP1 TO CHROMATIN

The influence of the metastasis promoting proteins mutant p53 (mtp53) and MDM2 on Cancer Persistent Repair (CPR) to promote cancer cell survival is understudied. Interactions between the DNA repair choice protein 53BP1 and wild type tumor suppressor protein p53 (wtp53) regulates cell cycle control. Cancer cells often express elevated levels of transcriptionally inactive missense mutant p53 (mtp53) that interacts with MDM2 and MDM4/MDMX (herein called MDMX). The ability of mtp53 to maintain a 53BP1 interaction while in the context of interactions with MDM2 and MDMX has not been described. We asked if MDM2 regulates chromatin-based phosphorylation events in the context of mtp53 by comparing the chromatin of T47D breast cancer cells with and without MDM2 in a phospho-peptide stable isotope labeling in cell culture (SILAC) screen. We found reduced phospho-53BP1 chromatin association, which we confirmed by chromatin fractionation and immunofluorescence in multiple breast cancer cell lines. We used the Proximity Ligation Assay (PLA) in breast cancer cell lines and detected 53BP1 in close proximity to mtp53, MDM2, and the DNA repair protein MDC1. Through disruption of the mtp53-MDM2 interaction, by either Nutlin 3a or a mtp53 R273H C-terminal deletion, we uncovered that mtp53 was required for MDM2-53BP1 interaction foci. Our data suggests that mtp53 works with MDM2 and 53BP1 to promote CPR and cell survival.

MDM2 amplification is rare in gastric cancer

The MDM2 proto-oncogene (MDM2) is a primary negative regulator of p53. The latter is frequently mutated in gastric cancer (GC). In the present study, we aimed to validate gene amplification, protein expression, and the putative tumor biological function of MDM2 in a well-characterized Western GC cohort. MDM2 amplification and protein expression were studied in a cohort of 327 GCs by fluorescence in situ hybridization (FISH) and immunohistochemistry. Gene amplification and protein expression were correlated with diverse clinicopathological patient characteristics including patient outcome. Immunohistochemically, 97 GCs (29.7%) were categorized as MDM2 positive and 230 GCs (70.3%) as negative. An amplification of MDM2 was found in 11 (3.4%) cases without evidence of intratumoral heterogeneity. Nine of these eleven (81.8%) cases showed MDM2 protein expression. MDM2 amplification correlated significantly with MDM2 protein expression (p < 0.001). On a case-by-case analysis, MDM2-amplified cases showed varied histological phenotypes and were most commonly microsatellite stable; EBV, HER2, and MET negative; and FGFR2 positive. A single case harbored both, MDM2 amplification and TP53 mutation. MDM2 amplification and MDM2 expression, respectively, did not correlate with overall or tumor-specific survival. Our targeted analysis of MDM2 in a well-characterized cohort of GC patients showed that MDM2 amplification is rare, of no specific histological phenotype, and may not be always mutually exclusive with TP53 mutations. Given the low number of cases, currently, no diagnostic or therapeutic recommendation related to MDM2 amplification can be given for GC of Western origin.

Single-nucleotide variants within heart enhancers increase binding affinity and disrupt heart development

Transcriptional enhancers direct precise gene expression patterns during development and harbor the majority of variants associated with phenotypic diversity, evolutionary adaptations, and disease. Pinpointing which enhancer variants contribute to changes in gene expression and phenotypes is a major challenge. Here, we find that suboptimal or low-affinity binding sites are necessary for precise gene expression during heart development. Single-nucleotide variants (SNVs) can optimize the affinity of ETS binding sites, causing gain-of-function (GOF) gene expression, cell migration defects, and phenotypes as severe as extra beating hearts in the marine chordate Ciona robusta. In human induced pluripotent stem cell (iPSC)-derived cardiomyocytes, a SNV within a human GATA4 enhancer increases ETS binding affinity and causes GOF enhancer activity. The prevalence of suboptimal-affinity sites within enhancers creates a vulnerability whereby affinity-optimizing SNVs can lead to GOF gene expression, changes in cellular identity, and organismal-level phenotypes that could contribute to the evolution of novel traits or diseases.

Association of TP53 rs1042522 G > C, MDM2 rs2279744 T > G, and miR-34b/c rs4938723 T > C polymorphisms with aneuploidy pregnancy susceptibility

BACKGROUND

Aneuploidy pregnancy is a severe major birth defect and causes about 50% spontaneous miscarriages with unknown etiology. To date, only a few epidemiological studies with small sample sizes have investigated the risk factors for aneuploidy pregnancy. TP53, MDM2, and miR-34b/c genes are implicated in tumorigenesis with aneuploidy, yet the function of their polymorphisms in aneuploidy pregnancy susceptibility needs to be clarified.

OBJECTIVE

To elucidate the association of TP53 rs1042522 G > C, MDM2 rs2279744 309 T > G, and miR-34b/c rs4938723 T > C specific polymorphisms with aneuploidy pregnancy.

METHODS

In the retrospective case-control study, 330 aneuploidies pregnancy women and 813 normal pregnancy controls were recruited between January 2018 and April 2022 at the First People's Hospital of Yunnan Province, Kunming, China. Three functional polymorphisms, the TP53 rs1042522 G > C (Arg72Pro), MDM2 rs2279744 309 T > G, and miR-34b/c rs4938723 T > C, were genotyped using the snapshot method.

RESULTS

The frequency distribution of three genotypic variants was not different between case and control pregnant women and was similar to with Hardy-Weinberg Equilibrium (HWE). However, in the younger subgroup (less than 35 years old), a significant difference was detected in allele and recessive model (p = 0.01). In the advanced age subgroup (more than or equal to 35 years old), G of MDM2 rs2279744 T > G revealed a significantly higher frequency in cases than controls (p = 0.045), and miR-34b/c rs4938723 T > C revealed a significant difference under the dominant model (p = 0.03), but no significant differences were observed in other models and in both younger and older subgroup (p > 0.05, respectively). These results suggest that individual polymorphisms were not associated with aneuploidy pregnancy, combined with age, they may serve as a risk factor for aneuploidy pregnancy.

CONCLUSION

Combination of TP53 rs1042522 G > C, MDM2 rs2279744 T > G, and miR-34b/c rs4938723 T > C polymorphisms with maternal age may be related to aneuploidy pregnancy susceptibility. These findings might elaborate on the genetic etiology of aneuploidy pregnancy.

Role of microRNAs in Chronic Lymphocytic Leukemia

Chronic Lymphocytic Leukemia (CLL) is the most common form of leukemia in adults, with a highly variable clinical course. Improvement in the knowledge of the molecular pathways behind this disease has led to the development of increasingly specific therapies, such as BCR signaling inhibitors and BCL-2 inhibitors. In this context, the emerging role of microRNAs (miRNAs) in CLL pathophysiology and their possible application in therapy is worth noting. MiRNAs are one of the most important regulatory molecules of gene expression. In CLL, they can act both as oncogenes and tumor suppressor genes, and the deregulation of specific miRNAs has been associated with prognosis, progression, and drug resistance. In this review, we describe the role of the miRNAs that primarily impact the disease, and how these miRNAs could be used as therapeutic tools. Certainly, the use of miRNAs in clinical practice is still limited in CLL. Many issues still need to be solved, particularly regarding their biological and safety profile, even if several studies have suggested their efficacy on the disease, alone or in combination with other drugs.

Role of p53 suppression in the pathogenesis of hepatocellular carcinoma

In the world, hepatocellular carcinoma (HCC) is among the top 10 most prevalent malignancies. HCC formation has indeed been linked to numerous etiological factors, including alcohol usage, hepatitis viruses and liver cirrhosis. Among the most prevalent defects in a wide range of tumours, notably HCC, is the silencing of the p53 tumour suppressor gene. The control of the cell cycle and the preservation of gene function are both critically important functions of p53. In order to pinpoint the core mechanisms of HCC and find more efficient treatments, molecular research employing HCC tissues has been the main focus. Stimulated p53 triggers necessary reactions that achieve cell cycle arrest, genetic stability, DNA repair and the elimination of DNA-damaged cells’ responses to biological stressors (like oncogenes or DNA damage). To the contrary hand, the oncogene protein of the murine double minute 2 (MDM2) is a significant biological inhibitor of p53. MDM2 causes p53 protein degradation, which in turn adversely controls p53 function. Despite carrying wt-p53, the majority of HCCs show abnormalities in the p53-expressed apoptotic pathway. High p53 in-vivo expression might have two clinical impacts on HCC: (1) Increased levels of exogenous p53 protein cause tumour cells to undergo apoptosis by preventing cell growth through a number of biological pathways; and (2) Exogenous p53 makes HCC susceptible to various anticancer drugs. This review describes the functions and primary mechanisms of p53 in pathological mechanism, chemoresistance and therapeutic mechanisms of HCC.

miR-3174 Is a New Tumor Suppressor MicroRNA That Inhibits Several Tumor-Promoting Genes in Glioblastoma

microRNAs (miRNAs) play an important role in the pathology of glioblastoma (GBM), which is the most malignant and most common primary malignant brain tumor. miRNAs can target multiple genes simultaneously and are considered as potential therapeutic agents or targets. This study aimed to determine the role of miR-3174 in the pathobiology of GBM using both in vitro and in vivo approaches. This is the first study deciphering the role of miR-3174 in GBM. We studied the expression of miR-3174 and found it to be downregulated in a panel of GBM cell lines, GSCs and tissues relative to astrocytes and normal brain tissue. This finding led us to hypothesize that miR-3174 has a tumor-suppressive role in GBM. Exogenous expression of miR-3174 inhibited GBM cell growth and invasion, and hampered the neurosphere formation ability of GSCs. miR-3174 downregulated the expression of multiple tumor-promoting genes including CD44, MDM2, RHOA, PLAU and CDK6. Further, overexpression of miR-3174 reduced tumor volume in nude mice with intracranial xenografts. Immuno-histochemical study of brain sections with intracranial tumor xenografts revealed the pro-apoptotic and anti-proliferative activity of miR-3174. In conclusion, we demonstrated that miR-3174 has a tumor-suppressive role in GBM and could be exploited for therapeutic purposes.

Sex-Specific Associations of MDM2 and MDM4 Variants with Risk of Multiple Primary Melanomas and Melanoma Survival in Non-Hispanic Whites

MDM2-SNP309 (rs2279744), a common genetic modifier of cancer incidence in Li-Fraumeni syndrome, modifies risk, age of onset, or prognosis in a variety of cancers. Melanoma incidence and outcomes vary by sex, and although SNP309 exerts an effect on the estrogen receptor, no consensus exists on its effect on melanoma. MDM2 and MDM4 restrain p53-mediated tumor suppression, independently or together. We investigated SNP309, an a priori MDM4-rs4245739, and two coinherited variants, in a population-based cohort of 3663 primary incident melanomas. Per-allele and per-haplotype (MDM2_SNP309-SNP285; MDM4_rs4245739-rs1563828) odds ratios (OR) for multiple-melanoma were estimated with logistic regression models. Hazard ratios (HR) for melanoma death were estimated with Cox proportional hazards models. In analyses adjusted for covariates, females carrying MDM4-rs4245739*C were more likely to develop multiple melanomas (ORper-allele = 1.25, 95% CI 1.03-1.51, and Ptrend = 0.03), while MDM2-rs2279744*G was inversely associated with melanoma-death (HRper-allele = 0.63, 95% CI 0.42-0.95, and Ptrend = 0.03). We identified 16 coinherited expression quantitative loci that control the expression of MDM2, MDM4, and other genes in the skin, brain, and lungs. Our results suggest that MDM4/MDM2 variants are associated with the development of subsequent primaries and with the death of melanoma in a sex-dependent manner. Further investigations of the complex MDM2/MDM4 motif, and its contribution to the tumor microenvironment and observed associations, are warranted.

Meta-Analysis of 49 SNPs Covering 25,446 Cases and 41,106 Controls Identifies Polymorphisms in Hormone Regulation and DNA Repair Genes Associated with Increased Endometrial Cancer Risk

Endometrial cancer (EC) is among the most common gynecological disorders globally. As single nucleotide polymorphisms (SNPs) play an important role in the causation of EC, therefore, a comprehensive meta-analysis of 49 SNPs covering 25,446 cases and 41,106 controls was performed to identify SNPs significantly associated with increased EC risk. PubMed was searched to identify case control studies and meta-analysis was performed to compute the pooled odds ratio (OR) at 95% confidence interval (CI). Cochran’s Q-test and I2 were used to study heterogeneity, based on which either a random or a fixed effect model was implemented. The meta-analysis identified 11 SNPs (from 10 genes) to be significantly associated with increased EC risk. Among these, seven SNPs were significant in at least three of the five genetic models, as well as three of the polymorphisms (rs1801320, rs11224561, and rs2279744) corresponding to RAD51, PGR, and MDM2 genes, which contained more than 1000 EC cases each and exhibited increased risk. The current meta-analysis indicates that polymorphisms associated with various hormone related genes—SULT1A1 (rs1042028), PGR (rs11224561), and CYP19A1 (rs10046 and rs4775936); DNA repair genes—ERCC2 (rs1799793), OGG1 (rs1052133), MLH1 (rs1800734), and RAD51 (rs1801320) as well as genes like MDM2 (rs2279744), CCND1 (rs9344), and SERPINE1 (rs1799889), are significantly associated with increased EC risk.

Synthesis and Biological Evaluation of Novel Dispiro-Indolinones with Anticancer Activity

Novel variously substituted thiohydantoin-based dispiro-indolinones were prepared using a regio- and diastereoselective synthetic route from 5-arylidene-2-thiohydantoins, isatines, and sarcosine. The obtained molecules were subsequently evaluated in vitro against the cancer cell lines LNCaP, PC3, HCT^wt, and HCT^(-/-). Several compounds demonstrated a relatively high cytotoxic activity vs. LNCaP cells (IC₅₀ = 1.2-3.5 µM) and a reasonable selectivity index (SI = 3-10). Confocal microscopy revealed that the conjugate of propargyl-substituted dispiro-indolinone with the fluorescent dye Sulfo-Cy5-azide was mainly localized in the cytoplasm of HEK293 cells. P388-inoculated mice and HCT116-xenograft BALB/c nude mice were used to evaluate the anticancer activity of compound 29 in vivo. Particularly, the TGRI value for the P388 model was 93% at the final control timepoint. No mortality was registered among the population up to day 31 of the study. In the HCT116 xenograft model, the compound (170 mg/kg, i.p., o.d., 10 days) provided a T/C ratio close to 60% on day 8 after the treatment was completed. The therapeutic index-estimated as LD₅₀/ED₅₀-for compound 29 in mice was ≥2.5. Molecular docking studies were carried out to predict the possible binding modes of the examined molecules towards MDM2 as the feasible biological target. However, such a mechanism was not confirmed by Western blot data and, apparently, the synthesized compounds have a different mechanism of cytotoxic action.

Sex differences in drug effects and/or toxicity in oncology

The prevalence, incidence, and severity of a wide variety of diseases and ailments are significantly influenced by the significant disparities that occur between the sexes. The way that men and women react to pharmacological treatment also varies. Therefore, it is crucial to comprehend these reactions in order to conduct risk assessment correctly and to develop safe and efficient therapies. Even from that limited vantage point, the manner and timing of our drug usage might have unintended and unanticipated consequences. There are sex-specific differences in the incidence and mortality of certain malignancies. One of the most important discoveries in cancer epidemiology is the gender inequalities. Cancer incidence differences between the sexes are thought to be regulated at the genetic and molecular levels and by sex hormones like oestrogen. Differences based on sex and gender are among the least investigated factors impacting cancer susceptibility, progression, survival, and therapy response despite their established importance in clinical care. The molecular mechanisms underlying sex differences in particular are poorly known, hence the majority of precision medicine approaches employ mutational or other genetic data to assign therapy without taking into account how the patient's sex may affect therapeutic efficacy. In patients receiving chemotherapy, there are definite gender-dependent disparities in response rates and the likelihood of side effects. This review explores the influence of sex as a biological variable in drug effects or toxicity in oncology.

NFκB-Mediated Expression of Phosphoinositide 3-Kinase δ Is Critical for Mesenchymal Transition in Retinal Pigment Epithelial Cells

Epithelial mesenchymal transition (EMT) plays a vital role in a variety of human diseases including proliferative vitreoretinopathy (PVR), in which retinal pigment epithelial (RPE) cells play a key part. Transcriptomic analysis showed that the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway was up-regulated in human RPE cells upon treatment with transforming growth factor (TGF)-β2, a multifunctional cytokine associated with clinical PVR. Stimulation of human RPE cells with TGF-β2 induced expression of p110δ (the catalytic subunit of PI3Kδ) and activation of NFκB/p65. CRISPR-Cas9-mediated depletion of p110δ or NFκB/p65 suppressed TGF-β2-induced fibronectin expression and activation of Akt as well as migration of these cells. Intriguingly, abrogating expression of NFκB/p65 also blocked TGF-β2-induced expression of p110δ, and luciferase reporter assay indicated that TGF-β2 induced NFκB/p65 binding to the promoter of the PIK3CD that encodes p110δ. These data reveal that NFκB/p65-mediated expression of PI3Kδ is essential in human RPE cells for TGF-β2-induced EMT, uncovering hindrance of TGF-β2-induced expression of p110δ as a novel approach to inhibit PVR.

A comprehensive study of p53 protein

The protein p53 has been extensively investigated since it was found 43 years ago and has become a "guardian of the genome" that regulates the division of cells by preventing the growth of cells and dividing them, that is, inhibits the development of tumors. Initial proof of protein existence by researchers in the mid-1970s was found by altering and regulating the SV40 big T antigen termed the A protein. Researchers demonstrated how viruses play a role in cancer by employing viruses' ability to create T-antigens complex with viral tumors, which was discovered in 1979 following a viral analysis and cancer analog research. Researchers later in the year 1989 explained that in Murine Friend, a virus-caused erythroleukemia, commonly found that p53 was inactivated to suggest that p53 could be a "tumor suppressor gene." The TP53 gene, encoding p53, is one of human cancer's most frequently altered genes. The protein-regulated biological functions of all p53s include cell cycles, apoptosis, senescence, metabolism of the DNA, angiogenesis, cell differentiation, and immunological response. We tried to unfold the history of the p53 protein, which was discovered long back in 1979, that is, 43 years of research on p53, and how p53's function has been developed through time in this article.

Association between TP53 Arg72Pro variant and recurrent pregnancy loss in the Greek population

OBJECTIVES

The present case-control study investigates whether TP53 Arg72Pro variant (rs1042522) serves as a risk factor for recurrent pregnancy loss (RPL) in Greek women.

METHODS

The study group consisted of 100 patients with at least two miscarriages of unexplained etiology, before the 24th week of gestation. The control group included 106 women with no pregnancy loss history. DNA was extracted and genotyped using specific primers for PCR amplification of the Arg72 and Pro72 alleles. Sanger sequencing was used for the discrimination between heterozygotes and homozygotes for Arg72Pro variant.

RESULTS

This is the first study demonstrating the statistically significant higher frequency of TP53 Arg72Pro variant in Greek RPL women compared to controls (38% vs. 6.6%; OR=8.6682, 95% CI: 3.6446-20.6160; p<0.0001). GC genotype (Arg/Pro) and CC genotype (Pro/Pro) were statistically more common in RPL patients than in controls (16% vs. 1.9%; p=0.0027, and 22 vs. 4.7%; p=0.0008, respectively). C allele frequency was statistically significant higher in RPL group than in controls (30.0 vs. 5.7%; p<0.0001). According to the inheritance mode analysis, the model that best fit the data was the dominant model (OR=8.67, 95% CI=3.64-20.62; p<0.0001).

CONCLUSIONS

The is the first study disclosing strong evidence that TP53 rs1042522 is significantly associated with a higher risk for recurrent pregnancy loss in Greek women following a dominant model, thus, serving as a genetic marker for identifying women at increased risk of recurrent miscarriages.

Lessons Learned From Parsing Genetic Risk for Schizophrenia Into Biological Pathways

The clinically heterogeneous presentation of schizophrenia is compounded by the heterogeneity of risk factors and neurobiological correlates of the disorder. Genome-wide association studies in schizophrenia have uncovered a remarkably high number of genetic variants, but the biological pathways they impact upon remain largely unidentified. Among the diverse methodological approaches employed to provide a more granular understanding of genetic risk for schizophrenia, the use of biological labels, such as gene ontologies, regulome approaches, and gene coexpression have all provided novel perspectives into how genetic risk translates into the neurobiology of schizophrenia. Here, we review the salient aspects of parsing polygenic risk for schizophrenia into biological pathways. We argue that parsed scores, compared to standard polygenic risk scores, may afford a more biologically plausible and accurate physiological modeling of the different dimensions involved in translating genetic risk into brain mechanisms, including multiple brain regions, cell types, and maturation stages. We discuss caveats, opportunities, and pitfalls inherent in the parsed risk approach.

A common pathway to cancer: Oncogenic mutations abolish p53 oscillations

The tumor suppressor p53 oscillates in response to DNA double-strand breaks, a behavior that has been suggested to be essential to its anti-cancer function. Nearly all human cancers have genetic alterations in the p53 pathway; a number of these alterations have been shown to be oncogenic by experiment. These alterations include somatic mutations and copy number variations as well as germline polymorphisms. Intriguingly, they exhibit a mixed pattern of interactions in tumors, such as co-occurrence, mutual exclusivity, and paradoxically, mutual antagonism. Using a differential equation model of p53-Mdm2 dynamics, we employ Hopf bifurcation analysis to show that these alterations have a common mode of action, to abolish the oscillatory competence of p53, thereby, we suggest, impairing its tumor suppressive function. In this analysis, diverse genetic alterations, widely associated with human cancers clinically, have a unified mechanistic explanation of their role in oncogenesis.

Association of functional genetic variants in TFF1 and nephrolithiasis risk in a Chinese population

Trefoil Factor 1 (TFF1) is considered to be able to inhibit the formation of kidney stone. However, genetic variants in TFF1 and corresponding function in kidney stone development are still not well studied. In this study, the discovery set including 230 cases and 250 controls was used to analyze the association between seven tagSNPs of TFF1 gene and the nephrolithiasis risk. Further evaluation was confirmed by the validation set comprising 307 cases and 461 controls. The consequences of the two-stage case–control study indicated that individuals with the rs3761376 A allele have significantly increased nephrolithiasis risk than those with the GG genotypes [adjusted odds ratio (OR) = 1.35, 95% confidence interval (CI) = 1.05–1.73]. Moreover, we also carried out a stratified analysis and found the increased nephrolithiasis risks at A allele among males, overweight individuals, no hypertensive individuals, nondiabetic individuals, smokers, and drinkers. In the following functional experiments, the notably lower expression of TFF1 was exhibited by the vectors carrying A allele compared with those carrying G allele in both luciferase (P = 0.022) and expression vectors (P = 0.041). In addition to tissue detection, we confirmed a significant inverse association of rs3761376 G > A and TFF1 gene expression (P < 0.001). These results suggest that TFF1 rs3761376 may serve as a potential biomarker to predict the risk of nephrolithiasis.

Associations of MDM2 rs2279744 and TP53 rs1042522 polymorphisms with cervical cancer risk: A meta-analysis and systematic review

Background

Although the association between MDM2 rs2279744 and TP53 rs1042522 polymorphisms and cervical cancer has been reported, the results of its correlation were contradictory. Thus, we conducted a meta-analysis to precisely verify the relationships between MDM2 rs2279744 and TP53 rs1042522 polymorphisms and cervical cancer.

Methods

We thoroughly searched the PubMed, Web of Science, Embase, and Scopus databases for all potential articles from inception to June 2022 and used R Version 4.1.2 and STATA software 12.0 for the meta-analysis. The odds ratios (ORs), 95% confidence intervals (CIs) and 95% prediction intervals (PIs) were calculated to evaluate the associations. Subgroup analyses stratified by ethnicity, source of control, quality score and adjustment were further conducted to assess the relationship between MDM2 rs2279744 and TP53 rs1042522 polymorphisms and cervical cancer.

Results

A total of 30 case-control studies involving 5025 cases and 6680 controls were included. All the included studies were population-based or hospital-based studies. The overall analysis showed that MDM2 rs2279744 polymorphism was closely related to an increased risk of cervical cancer in the recessive model (GG vs GT + TT: OR = 1.602, 95% CI: 1.077-2.383, P = 0.020) and homozygote model (GG vs TT: OR = 1.469, 95% CI: 1.031-2.095, P = 0.033, 95% PI: 0.516-4.184). A significant correlation between TP53 rs1042522 polymorphism and cervical cancer was observed in two models (CC + CG vs GG: OR = 1.759, 95% CI: 1.192-2.596, P = 0.004, 95% PI: 0.474-6.533; GG vs CC: OR = 2.442, 95% CI: 1.433-4.162, P = 0.001, 95% PI: 0.456-13.071).

Conclusions

This meta-analysis revealed that MDM2 SNP309T&gt;G and TP53 rs1042522 C&gt;G polymorphisms were associated with the increased risk of cervical cancer.

Impact on breast cancer susceptibility and clinicopathological traits of common genetic polymorphisms in TP53, MDM2 and ATM genes in Sardinian women

Common variants of genes involved in DNA damage correction [tumor protein p53 (TP53), murine double 2 homolog oncoprotein (MDM2) and ataxia-telengiectasia mutated (ATM)] may serve a role in cancer predisposition. The purpose of the present study was to investigate the association of five variants in these genes with breast cancer risk and clinicopathological traits in a cohort of 261 women from northern Sardinia. Polymorphic variants in TP53 (rs17878362, rs1042522 and rs1625895), MDM2 (rs2279744) and ATM (rs1799757) were determined by PCR and TaqMan single nucleotide polymorphism assay in patients with breast cancer (n=136) and healthy controls (n=125). Association with clinicopathological (e.g., age at diagnosis, lymph node involvement, clinical stage) and lifestyle factors (e.g., smoking status, alcohol intake, contraceptive use) was also evaluated. TP53 rs17878362 and rs1625895 polymorphisms were associated with decreased risk of BC diagnosis in patients older than 50 years (codominant and recessive models) and post-menopause (recessive model). Furthermore, there was a significant association between lymph node status (positive vs. negative) and ATM rs1799757-delT in dominant and additive models and between MDM2 rs2279744-allele and use of oral contraceptives. This analysis suggested that TP53 rs17878362 and rs1625895 may affect age of onset of breast cancer and ATM rs1799757 and MDM2 rs2279744 may be associated with lymph node status and prolonged use of oral contraceptives, respectively.

Functional variant rs2270363 on 16p13.3 confers schizophrenia risk by regulating NMRAL1

Recent genome-wide association studies have reported multiple schizophrenia risk loci, yet the functional variants and their roles in schizophrenia remain to be characterized. Here we identify a functional single nucleotide polymorphism (rs2270363: G>A) at the schizophrenia risk locus 16p13.3. rs2270363 lies in the E-box element of the promoter of NMRAL1 and disrupts binding of the basic helix-loop-helix leucine zipper family proteins, including USF1, MAX and MXI1. We validated the regulatory effects of rs2270363 using reporter gene assays and electrophoretic mobility shift assay. Besides, expression quantitative trait loci analysis showed that the risk allele (A) of rs2270363 was significantly associated with elevated NMRAL1 expression in the human brain. Transcription factors knockdown and CRISPR-Cas9-mediated editing further confirmed the regulatory effects of the genomic region containing rs2270363 on NMRAL1. Intriguingly, NMRAL1 was significantly downregulated in the brain of schizophrenia patients compared with healthy subjects, and knockdown of Nmral1 expression affected proliferation and differentiation of mouse neural stem cells, as well as genes and pathways associated with brain development and synaptic transmission. Of note, Nmral1 knockdown resulted in significant decrease of dendritic spine density, revealing the potential pathophysiological mechanisms of NMRAL1 in schizophrenia. Finally, we independently confirmed the association between rs2270363 and schizophrenia in the Chinese population and found that the risk allele of rs2270363 was the same in European and Chinese populations. These lines of evidence suggest that rs2270363 may confer schizophrenia risk by regulating NMRAL1, a gene whose expression dysregulation might be involved in the pathogenesis of schizophrenia by affecting neurodevelopment and synaptic plasticity.

Li–Fraumeni Syndrome: Mutation of TP53 Is a Biomarker of Hereditary Predisposition to Tumor: New Insights and Advances in the Treatment

Simple Summary

Li–Fraumeni Syndrome (LFS) is a rare tumor predisposition syndrome in which the tumor suppressor TP53 gene is mutated in the germ cell population. LFS patients develop a broad spectrum of cancers in their lifetime. The risk to develop these tumors is not decreased by any type of treatment and if the analysis of the TP53 mutational status in the family members was not possible, tumors are often diagnosed in already advanced stages. This review aims to report the evidence for novel mechanisms of tumor onset related to germline TP53 mutations and possible treatments.

Abstract

Li–Fraumeni syndrome (LFS) is a rare familial tumor predisposition syndrome with autosomal dominant inheritance, involving germline mutations of the TP53 tumor suppressor gene. The most frequent tumors that arise in patients under the age of 45 are osteosarcomas, soft-tissue sarcomas, breast tumors in young women, leukemias/lymphomas, brain tumors, and tumors of the adrenal cortex. To date, no other gene mutations have been associated with LFS. The diagnosis is usually confirmed by genetic testing for the identification of TP53 mutations; therefore, these mutations are considered the biomarkers associated with the tumor spectrum of LFS. Here, we aim to review novel molecular mechanisms involved in the oncogenic functions of mutant p53 in LFS and to discuss recent new diagnostic and therapeutic approaches exploiting TP53 mutations as biomarkers and druggable targets.

The Next Frontier: Translational Development of Ubiquitination, SUMOylation, and NEDDylation in Cancer

Post-translational modifications of proteins ensure optimized cellular processes, including proteostasis, regulated signaling, cell survival, and stress adaptation to maintain a balanced homeostatic state. Abnormal post-translational modifications are associated with cellular dysfunction and the occurrence of life-threatening diseases, such as cancer and neurodegenerative diseases. Therefore, some of the frequently seen protein modifications have been used as disease markers, while others are targeted for developing specific therapies. The ubiquitin and ubiquitin-like post-translational modifiers, namely, small ubiquitin-like modifier (SUMO) and neuronal precursor cell-expressed developmentally down-regulated protein 8 (NEDD8), share several features, such as protein structures, enzymatic cascades mediating the conjugation process, and targeted amino acid residues. Alterations in the regulatory mechanisms lead to aberrations in biological processes during tumorigenesis, including the regulation of tumor metabolism, immunological modulation of the tumor microenvironment, and cancer stem cell stemness, besides many more. Novel insights into ubiquitin and ubiquitin-like pathways involved in cancer biology reveal a potential interplay between ubiquitination, SUMOylation, and NEDDylation. This review outlines the current understandings of the regulatory mechanisms and assay capabilities of ubiquitination, SUMOylation, and NEDDylation. It will further highlight the role of ubiquitination, SUMOylation, and NEDDylation in tumorigenesis.

The MDM2 Single-Nucleotide Polymorphism T309G Is Associated With the Development of Epimacular Membranes

Purpose: To investigate the role of the mouse double minute 2 (MDM2) gene single-nucleotide polymorphism (SNP) T309G in the development of epimacular membranes (EMMs) by analyzing the genotype distribution and consistency of the polymorphism in paired membrane-blood samples.

Methods: This was a cross–sectional genetic association study of patients with proliferative vitreoretinopathy (PVR) or EMMs. PVR membranes (PVRMs), internal limiting membranes (ILMs) (PVR-ILMs) and blood samples (PVR-blood) from patients with PVR, and EMMs, EMM-ILMs and EMM-blood from patients with EMMs were collected. The genotype of all samples was determined by Sanger sequencing. Sex composition, mean age, the genotype distribution of MDM2 T309G, the allelic frequency of the MDM2 SNP309 G allele (% G) and the somatic mutation rate at the MDM2 T309G locus (% M) were analyzed and compared. The PVR and healthy Chinese donor groups were used as controls for different comparisons.

Results: The EMM group of 62 patients was older than the PVR group of 61 patients by an average of 8.87 years (p < 0.0001), but the two groups were statistically similar in the sex composition (p = 0.1754). Importantly, G allele carriers were at a higher risk of developing EMMs than non-G allele carriers (p = 0.0479; OR = 2.047). Moreover, EMM-blood exhibited a significantly higher % G than blood samples from healthy Chinese donors (EMM-blood: 56.78%, donors: 45.61%; p = 0.0256; OR = 1.567). Regarding membrane-blood consistency, % M was significantly different between PVRMs and EMMs (PVRMs: 2.63%, EMMs: 21.57%; p = 0.0097; OR = 10.18) but not between different types of ILMs (PVR-ILMs: 18.18%, EMM-ILMs: 29.17%; p = 0.6855). Furthermore, EMMs (p = 0.0053; OR = 8.250) and EMM-ILMs (p = 0.0233; OR = 14.40) from patients with preoperative macular holes were more predisposed toward somatic mutations at the MDM2 T309G locus than those from patients without preoperative macular holes.

Conclusions:MDM2 T309G is associated with the development of EMMs. Herein, the MDM2 SNP309 G allele is first reported as an associated factor of EMMs in a Chinese population. In addition, EMMs and ILMs are genetically unstable at the MDM2 T309G locus, especially when complicated with preoperative macular holes.

Genetic polymorphisms and protein levels in vocal fold leukoplakia: a systematic review

Vocal fold leukoplakia (VFL) has a risk of malignant transformation. Therefore, patients can have symptoms such as dysphonia, vocal strain, difficulty breathing, and dysphagia. Additionally, there is a genetic predisposition that can be associated with genetic polymorphisms. We aimed to evaluate the influence of genetic polymorphisms and protein levels in the etiology of VFL. Our study followed the PRISMA checklist and was registered on PROSPERO database. The questions were: "Are genetic polymorphisms involved in the etiology of VFL? Are protein levels altered in patients with VFL?". Eligibility criteria were case control studies that compared the presence of polymorphisms or/and protein levels of subjects diagnosed with VFL and healthy controls. Of the 905 articles retrieved, five articles with a total of 1038 participants were included in this study. The C allele of the single nucleotide polymorphisms (SNP)-819 T/C IL-10, A allele of the SNP -592 A/C IL-10, CT genotype of the SNP rs11886868 C/T BCL11A, GG genotype of the SNP rs4671393 A/G BCL11A, LL genotype, and L allele of (GT)n repeat polymorphisms of the HO-1 were risk factors for VFL development. Nevertheless, there was a lack of association between VFL and the -1082 A/G IL-10, rs14024 CK-1, and -309 T/G Mdm2 SNPs. The concentrations of the MDM2, BCL11A, and HO-1 proteins were modified, while IL-10 levels were normally expressed in these subjects. In conclusion, most markers evaluated in this review could be potential indicators to develop effective therapies, avoiding a malignant transformation of the lesion.

Association between ТР53, MDM2 and NQO1 gene polymorphisms and viral load among women with human papillomavirus

The risk of cervical cancer is caused by persistent human papillomavirus (HPV) infection. Cervical cancer is the most frequent cancer among women. Our purpose was to investigate the association between TP53 215C>G (Pro72Arg), MDM2 -410T>G, and NQO1 609C>T gene polymorphisms with a high HPV load and the inf luence of gene-gene interactions on prolonged HPV infection. Eighty-nine women with a high HPV viral load and 114 healthy women were involved in a case–control study. Genotyping for TP53 215C>G (Pro72Arg) and MDM2 -410T>G SNPs was carried out by allele-specif ic PCR and genotyping for NQO1 609C>T was performed by a TaqMan assay. Quantitative analysis of HPV DNA was performed by AmpliSens® HPV HCR screen-titer-FRT test system. Gene-gene interactions were analyzed using the multifactor dimensionality reduction (MDR) method. The study of separate SNPs of MDM2 -410T>G and NQO1 609C>T genes did not reveal any statistically signif icant difference in genotype and allele frequencies among women within the two groups. The frequency of the 215G (72Arg) allele and 215GG (72Arg/ Arg) genotype of the TP53 gene was signif icantly higher in the case group than in the control group (OR = 1.74, 95 % CI = 1.10–2.73; p = 0.02 and OR = 1.97, 95 % CI = 1.13–3.46; p = 0.04, respectively). MDR analysis showed the signif icance of intergenic interactions of the three studied loci TP53 (rs1042522) – MDM2 (rs2279744) – NQO1 (rs1800566) for the formation of a high HPV load (OR = 3.05, 95 % CI = 1.73–5.46; p = 0.0001).

Exploring the effects of genetic variation on gene regulation in cancer in the context of 3D genome structure

Background

Numerous genome-wide association studies (GWAS) conducted to date revealed genetic variants associated with various diseases, including breast and prostate cancers. Despite the availability of these large-scale data, relatively few variants have been functionally characterized, mainly because the majority of single-nucleotide polymorphisms (SNPs) map to the non-coding regions of the human genome. The functional characterization of these non-coding variants and the identification of their target genes remain challenging.

Results

In this communication, we explore the potential functional mechanisms of non-coding SNPs by integrating GWAS with the high-resolution chromosome conformation capture (Hi-C) data for breast and prostate cancers. We show that more genetic variants map to regulatory elements through the 3D genome structure than the 1D linear genome lacking physical chromatin interactions. Importantly, the association of enhancers, transcription factors, and their target genes with breast and prostate cancers tends to be higher when these regulatory elements are mapped to high-risk SNPs through spatial interactions compared to simply using a linear proximity. Finally, we demonstrate that topologically associating domains (TADs) carrying high-risk SNPs also contain gene regulatory elements whose association with cancer is generally higher than those belonging to control TADs containing no high-risk variants.

Conclusions

Our results suggest that many SNPs may contribute to the cancer development by affecting the expression of certain tumor-related genes through long-range chromatin interactions with gene regulatory elements. Integrating large-scale genetic datasets with the 3D genome structure offers an attractive and unique approach to systematically investigate the functional mechanisms of genetic variants in disease risk and progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12863-021-01021-x.

Systemic Treatment of Ewing Sarcoma: Current Options and Future Perspectives

Ewing sarcoma (ES) is an uncommon malignant neoplasm, mostly affecting young adults and adolescents. Surgical excision, irradiation, and combinations of multiple chemotherapeutic agents are currently used as a multimodal strategy for the treatment of local and oligometastatic disease. Although ES usually responds to the primary treatment, relapsed and primarily refractory disease remains a difficult therapeutic challenge. The growing understanding of cancer biology and the subsequent development of new therapeutic strategies have been put at the service of research in recurrent and refractory ES, generating a great number of ongoing studies with compounds that could find superior clinical outcomes in the years to come. This review gathers the current available information on the treatment and clinical investigation of ES and aims to be a point of support for future research.

It’s Getting Complicated—A Fresh Look at p53-MDM2-ARF Triangle in Tumorigenesis and Cancer Therapy

Anti-tumorigenic mechanisms mediated by the tumor suppressor p53, upon oncogenic stresses, are our bodies’ greatest weapons to battle against cancer onset and development. Consequently, factors that possess significant p53-regulating activities have been subjects of serious interest from the cancer research community. Among them, MDM2 and ARF are considered the most influential p53 regulators due to their abilities to inhibit and activate p53 functions, respectively. MDM2 inhibits p53 by promoting ubiquitination and proteasome-mediated degradation of p53, while ARF activates p53 by physically interacting with MDM2 to block its access to p53. This conventional understanding of p53-MDM2-ARF functional triangle have guided the direction of p53 research, as well as the development of p53-based therapeutic strategies for the last 30 years. Our increasing knowledge of this triangle during this time, especially through identification of p53-independent functions of MDM2 and ARF, have uncovered many under-appreciated molecular mechanisms connecting these three proteins. Through recognizing both antagonizing and synergizing relationships among them, our consideration for harnessing these relationships to develop effective cancer therapies needs an update accordingly. In this review, we will re-visit the conventional wisdom regarding p53-MDM2-ARF tumor-regulating mechanisms, highlight impactful studies contributing to the modern look of their relationships, and summarize ongoing efforts to target this pathway for effective cancer treatments. A refreshed appreciation of p53-MDM2-ARF network can bring innovative approaches to develop new generations of genetically-informed and clinically-effective cancer therapies.

Combined MEK/MDM2 inhibition demonstrates antitumor efficacy in TP53 wild-type thyroid and colorectal cancers with MAPK alterations

Most tumors with activating MAPK (mitogen-activated protein kinase) pathway alterations respond poorly to MEK inhibitors alone. Here, we evaluated combination therapy with MEK inhibitor selumetinib and MDM2 inhibitor KRT-232 in TP53 wild-type and MAPK altered colon and thyroid cancer models. In vitro, we showed synergy between selumetinib and KRT-232 on cell proliferation and colony formation assays. Immunoblotting confirmed p53 upregulation and MEK pathway inhibition. The combination was tested in vivo in seven patient-derived xenograft (PDX) models (five colorectal carcinoma and two papillary thyroid carcinoma models) with different KRAS, BRAF, and NRAS mutations. Combination therapy significantly prolonged event-free survival compared with monotherapy in six of seven models tested. Reverse-phase protein arrays and immunohistochemistry, respectively, demonstrated upregulation of the p53 pathway and in two models cleaved caspase 3 with combination therapy. In summary, combined inhibition of MEK and MDM2 upregulated p53 expression, inhibited MAPK signaling and demonstrated greater antitumor efficacy than single drug therapy in both in vitro and in vivo settings. These findings support further clinical testing of the MEK/MDM2 inhibitor combination in tumors of epithelial origin with MAPK pathway alterations.

The roles of mouse double minute 2 (MDM2) oncoprotein in ocular diseases: A review

Mouse double minute 2 (MDM2), an E3 ubiquitin ligase and the primary negative regulator of the tumor suppressor p53, cooperates with its structural homolog MDM4/MDMX to control intracellular p53 level. In turn, overexpression of p53 upregulates and forms an autoregulatory feedback loop with MDM2. The MDM2-p53 axis plays a pivotal role in modulating cell cycle control and apoptosis. MDM2 itself is regulated by the PI3K-AKT and RB-E2F-ARF pathways. While amplification of the MDM2 gene or overexpression of MDM2 (due to MDM2 SNP T309G, for instance) is associated with various malignancies, numerous studies have shown that MDM2/p53 alterations may also play a part in the pathogenetic process of certain ocular disorders (Fig. 1). These include cancers (retinoblastoma, uveal melanoma), fibrocellular proliferative diseases (proliferative vitreoretinopathy, pterygium), neovascular diseases, degenerative diseases (cataract, primary open-angle glaucoma, age-related macular degeneration) and infectious/inflammatory diseases (trachoma, uveitis). In addition, MDM2 is implicated in retinogenesis and regeneration after optic nerve injury. Anti-MDM2 therapy has shown potential as a novel approach to treating these diseases. Despite major safety concerns, there are high expectations for the clinical value of reformative MDM2 inhibitors. This review summarizes important findings about the role of MDM2 in ocular pathologies and provides an overview of recent advances in treating these diseases with anti-MDM2 therapies.

Systematic identification of genomic elements that regulate FCGR2A expression and harbor variants linked with autoimmune disease

BACKGROUND

FCGR2A binds antibody-antigen complexes to regulate the abundance of circulating and deposited complexes along with downstream immune and autoimmune responses. Although the abundance of FCRG2A may be critical in immune-mediated diseases, little is known about whether its surface expression is regulated through cis genomic elements and non-coding variants. In the current study, we aimed to characterize the regulation of FCGR2A expression, the impact of genetic variation and its association with autoimmune disease.

METHODS

We applied CRISPR-based interference and editing to scrutinize 1.7 Mb of open chromatin surrounding the FCGR2A gene to identify regulatory elements. Relevant transcription factors (TFs) binding to these regions were defined through public databases. Genetic variants affecting regulation were identified using luciferase reporter assays and were verified in a cohort of 1996 genotyped healthy individuals using flow cytometry.

RESULTS

We identified a complex proximal region and five distal enhancers regulating FCGR2A. The proximal region split into subregions upstream and downstream of the transcription start site, was enriched in binding of inflammation-regulated TFs, and harbored a variant associated with FCGR2A expression in primary myeloid cells. One distal enhancer region was occupied by CCCTC-binding factor (CTCF) whose binding site was disrupted by a rare genetic variant, altering gene expression.

CONCLUSIONS

The FCGR2A gene is regulated by multiple proximal and distal genomic regions, with links to autoimmune disease. These findings may open up novel therapeutic avenues where fine-tuning of FCGR2A levels may constitute a part of treatment strategies for immune-mediated diseases.

The mouse double minute 2 polymorphism is associated with both decreased p53 expression and poor clinicopathological outcomes of gastric cancer

This study aimed to determine the mouse double minute 2 (MDM2) SNP309 polymorphism and to evaluate MDM2 and p53 expression and the association of MDM2 positivity in gastric cancer and clinicopathological outcomes. A total of 400 patients with chronic gastritis, precancerous lesions, and gastric cancer were used to identify the MDM2 SNP309 polymorphism by using the Taq Man SNP Genotyping assay. Immunohistochemistry was performed to evaluate MDM2 and p53 expression. The associations of polymorphisms, protein expression, clinicopathological outcomes, and gastric cancer risk were calculated by multivariate Cox proportional hazards regression model analysis and expressed by odds ratios (ORs) and 95% confidence intervals (CIs). The MDM2 SNP309 G/G homozygous polymorphism was significantly associated with expressed MDM2 in gastric cancer (OR = 1.57, 95% CI = 1.39-2.03, P = 0.039). Moreover, in gastric cancer, p53 was significantly decreased compared to MDM2 (P = 0.007). However, MDM2 and p53 expression were not significantly different among genotypes, and the G/G genotype can result in the altered protein expression of p53 in gastric cancer. Clinicopathological outcome was significantly associated with MDM2 expression, including tumor location in the upper gastric region (OR = 1.48, 95% CI = 1.25-3.54, P = 0.037), undifferentiated type (OR = 2.47, 95% CI = 1.38-4.14, P = 0.016), presence of lymphatic invasion (OR = 1.96, 95% CI = 1.22-3.19, P = 0.014), and unresectable tumor (OR = 3.39, 95% CI = 1.61-4.94, P = 0.017). Our study indicated associations of the MDM2 SNP309 G/G homozygous polymorphism, MDM2 and p53 expression. Therefore, G/G-associated MDM2 revealed that P53 expression was decreased in gastric cancer and poor clinicopathological outcomes. Understanding the genetic polymorphisms and expression of MDM2 may help explain gastric cancer risk.

Resistance mechanisms to inhibitors of p53-MDM2 interactions in cancer therapy: can we overcome them?

Since the discovery of the first MDM2 inhibitors, we have gained deeper insights into the cellular roles of MDM2 and p53. In this review, we focus on MDM2 inhibitors that bind to the p53-binding domain of MDM2 and aim to disrupt the binding of MDM2 to p53. We describe the basic mechanism of action of these MDM2 inhibitors, such as nutlin-3a, summarise the determinants of sensitivity to MDM2 inhibition from p53-dependent and p53-independent points of view and discuss the problems with innate and acquired resistance to MDM2 inhibition. Despite progress in MDM2 inhibitor design and ongoing clinical trials, their broad use in cancer treatment is not fulfilling expectations in heterogenous human cancers. We assess the MDM2 inhibitor types in clinical trials and provide an overview of possible sources of resistance to MDM2 inhibition, underlining the need for patient stratification based on these aspects to gain better clinical responses, including the use of combination therapies for personalised medicine.

Avoidance or adaptation of radiotherapy in patients with cancer with Li-Fraumeni and heritable TP53-related cancer syndromes

The management of patients with cancer and Li-Fraumeni or heritable TP53-related cancer syndromes is complex because of their increased risk of developing second malignant neoplasms after genotoxic stresses such as systemic treatments or radiotherapy (radiosusceptibility). Clinical decision making also integrates the risks of normal tissue toxicity and sequelae (radiosensitivity) and tumour response to radiotherapy (radioresistance and radiocurability). Radiotherapy should be avoided in patients with cancer and Li-Fraumeni or heritable TP53 cancer-related syndromes, but overall prognosis might be poor without radiotherapy: radioresistance in these patients seems similar to or worse than that of the general population. Radiosensitivity in germline TP53 variant carriers seems similar to that in the general population. The risk of second malignant neoplasms according to germline TP53 variant and the patient's overall oncological prognosis should be assessed during specialised multidisciplinary staff meetings. Radiotherapy should be avoided whenever other similarly curative treatment options are available. In other cases, it should be adapted to minimise the risk of second malignant neoplasms in patients who still require radiotherapy despite its genotoxicity, in view of its potential benefit. Adaptations might be achieved through the reduction of irradiated volumes using proton therapy, non-ionising diagnostic procedures, image guidance, and minimal stray radiation. Non-ionising imaging should become more systematic. Radiotherapy approaches that might result in a lower probability of misrepaired DNA damage (eg, particle therapy biology and tumour targeting) are an area of investigation.

Medical guidelines for Li-Fraumeni syndrome 2019, version 1.1

Li–Fraumeni syndrome (LFS) is a hereditary tumor that exhibits autosomal dominant inheritance. LFS develops in individuals with a pathogenic germline variant of the cancer-suppressor gene, TP53 (individuals with TP53 pathogenic variant). The number of individuals with TP53 pathogenic variant among the general population is said to be 1 in 500 to 20,000. Meanwhile, it is found in 1.6% (median value, range of 0–6.7%) of patients with pediatric cancer and 0.2% of adult patients with cancer. LFS is diagnosed by the presence of germline TP53 pathogenic variants. However, patients can still be diagnosed with LFS even in the absence of a TP53 pathogenic variant if the familial history of cancers fit the classic LFS diagnostic criteria. It is recommended that TP53 genetic testing be promptly performed if LFS is suspected. Chompret criteria are widely used for the TP53 genetic test. However, as there are a certain number of cases of LFS that do not fit the criteria, if LFS is suspected, TP53 genetic testing should be performed regardless of the criteria. The probability of individuals with TP53 pathogenic variant developing cancer in their lifetime (penetrance) is 75% for men and almost 100% for women. The LFS core tumors (breast cancer, osteosarcoma, soft tissue sarcoma, brain tumor, and adrenocortical cancer) constitute the majority of cases; however, various types of cancers, such as hematological malignancy, epithelial cancer, and pediatric cancers, such as neuroblastoma, can also develop. Furthermore, approximately half of the cases develop simultaneous or metachronous multiple cancers. The types of TP53 pathogenic variants and factors that modify the functions of TP53 have an impact on the clinical presentation, although there are currently no definitive findings. There is currently no cancer preventive agent for individuals with TP53 pathogenic variant. Surgical treatments, such as risk-reducing bilateral mastectomy warrant further investigation. Theoretically, exposure to radiation could induce the onset of secondary cancer; therefore, imaging and treatments that use radiation should be avoided as much as possible. As a method to follow-up LFS, routine cancer surveillance comprising whole-body MRI scan, brain MRI scan, breast MRI scan, and abdominal ultrasonography (US) should be performed immediately after the diagnosis. However, the effectiveness of this surveillance is unknown, and there are problems, such as adverse events associated with a high rate of false positives, overdiagnosis, and sedation used during imaging as well as negative psychological impact. The detection rate of cancer through cancer surveillance is extremely high. Many cases are detected at an early stage, and treatments are low intensity; thus, cancer surveillance could contribute to an improvement in QOL, or at least, a reduction in complications associated with treatment. With the widespread use of genomic medicine, the diagnosis of LFS is unavoidable, and a comprehensive medical care system for LFS is necessary. Therefore, clinical trials that verify the feasibility and effectiveness of the program, comprising LFS registry, genetic counseling, and cancer surveillance, need to be prepared.

Racial disparity in prostate cancer in the African American population with actionable ideas and novel immunotherapies

BACKGROUND

African Americans (AAs) in the United States are known to have a higher incidence and mortality for Prostate Cancer (PCa). The drivers of this epidemiological disparity are multifactorial, including socioeconomic factors leading to lifestyle and dietary issues, healthcare access problems, and potentially tumor biology.

RECENT FINDINGS

Although recent evidence suggests once access is equal, AA men have equal outcomes to Caucasian American (CA) men, differences in PCa incidence remain, and there is much to do to reverse disparities in mortality across the USA. A deeper understanding of these issues, both at the clinical and molecular level, can facilitate improved outcomes in the AA population. This review first discusses PCa oncogenesis in the context of its diverse hallmarks before benchmarking key molecular and genomic differences for PCa in AA men that have emerged in the recent literature. Studies have emphasized the importance of tumor microenvironment that contributes to both the unequal cancer burden and differences in clinical outcome between the races. Management of comorbidities like obesity, hypertension, and diabetes will provide an essential means of reducing prostate cancer incidence in AA men. Although requiring further AA specific research, several new treatment strategies such as immune checkpoint inhibitors used in combination PARP inhibitors and other emerging vaccines, including Sipuleucel-T, have demonstrated some proven efficacy.

CONCLUSION

Genomic profiling to integrate clinical and genomic data for diagnosis, prognosis, and treatment will allow physicians to plan a "Precision Medicine" approach to AA men. There is a pressing need for further research for risk stratification, which may allow early identification of AA men with higher risk disease based on their unique clinical, genomic, and immunological profiles, which can then be mapped to appropriate clinical trials. Treatment options are outlined, with a concise description of recent work in AA specific populations, detailing several targeted therapies, including immunotherapy. Also, a summary of current clinical trials involving AA men is presented, and it is important that policies are adopted to ensure that AA men are actively recruited. Although it is encouraging that many of these explore the lifestyle and educational initiatives and therapeutic interventions, there is much still work to be done to reduce incidence and mortality in AA men and equalize current racial disparities.

Biomolecular Markers of Recurrent Implantation Failure-A Review

Currently, infertility affects 8–12% of reproductive age couples worldwide, a problem that also affects women suffering from recurrent implantation failure (RIF). RIF is a complex condition resulting from many physiological and molecular mechanisms involving dynamic endometrium–blastocyst interaction. The most important are the endometrial receptivity process, decidualization, trophoblast invasion, and blastocyst nesting. Although the exact multifactorial pathogenesis of RIF remains unclear, many studies have suggested the association between hormone level imbalance, disturbances of angiogenic and immunomodulatory factors, certain genetic polymorphisms, and occurrence of RIF. These studies were performed in quite small groups. Additionally, the results are inconsistent between ethnicities. The present review briefly summarizes the importance of factors involved in RIF development that could also serve as diagnostic determinants. Moreover, our review could constitute part of a new platform for discovery of novel diagnostic and therapeutic solutions for RIF.

Chemotherapy of HER2- and MDM2-Enriched Breast Cancer Subtypes Induces Homologous Recombination DNA Repair and Chemoresistance

Simple Summary

MDM2 is a protein responsible for negative regulation of the p53 tumor suppressor. In addition, MDM2 exhibits chaperone-like properties similar to the HSP90 molecular chaperone. Multiple studies revealed that MDM2 is deeply involved in cancer development and progression. Some recently published results indicate that the role of MDM2 in DNA repair inhibition is more complex than previously thought. We show that MDM2 is directly involved in the homologous recombination DNA repair, and its chaperone-like activity is crucial for this function. The DNA repair inhibition is a result of inefficient MDM2 dissociation from the NBN protein complex. When cancer cells are treated with chemotherapy, MDM2 can be easily released from the interaction and degraded, resulting in effective homologous recombination DNA repair, which translates into the acquisition of a chemoresistant phenotype by the tumor. This knowledge may allow for identification of the patients that are at particular risk of tumor chemoresistance.

Abstract

Analyzing the TCGA breast cancer database, we discovered that patients with the HER2 cancer subtype and overexpression of MDM2 exhibited decreased post-treatment survival. Inhibition of MDM2 expression in the SKBR3 cell line (HER2 subtype) diminished the survival of cancer cells treated with doxorubicin, etoposide, and camptothecin. Moreover, we demonstrated that inhibition of MDM2 expression diminished DNA repair by homologous recombination (HR) and sensitized SKBR3 cells to a PARP inhibitor, olaparib. In H1299 (TP53^−/−) cells treated with neocarzinostatin (NCS), overexpression of MDM2 WT or E3-dead MDM2 C478S variant stimulated the NCS-dependent phosphorylation of ATM, NBN, and BRCA1, proteins involved in HR DNA repair. However, overexpression of chaperone-dead MDM2 K454A variant diminished phosphorylation of these proteins as well as the HR DNA repair. Moreover, we demonstrated that, upon NCS treatment, MDM2 K454A interacted with NBN more efficiently than MDM2 WT and that MDM2 WT was degraded more efficiently than MDM2 K454A. Using a proliferation assay, we showed that overexpression of MDM2 WT, but not MDM2 K454A, led to acquisition of resistance to NCS. The presented results indicate that, following chemotherapy, MDM2 WT was released from MDM2-NBN complex and efficiently degraded, hence allowing extensive HR DNA repair leading to the acquisition of chemoresistance by cancer cells.