Mutant p53: Multiple Mechanisms Define Biologic Activity in Cancer

Decoding the molecular symphony: interactions between the m6A and p53 signaling pathways in cancer

The p53 tumor suppressor gene governs a multitude of complex cellular processes that are essential for anti-cancer function and whose dysregulation leads to aberrant gene transcription, activation of oncogenic signaling and cancer development. Although mutations can occur at any point in the genetic sequence, missense mutations comprise the majority of observed p53 mutations in cancers regardless of whether the mutation is germline or somatic. One biological process involved in both mutant and wild-type p53 signaling is the N 6-methyladenosine (m6A) epitranscriptomic network, a type of post-transcriptional modification involved in over half of all eukaryotic mRNAs. Recently, a significant number of findings have demonstrated unique interactions between p53 and the m6A epitranscriptomic network in a variety of cancer types, shedding light on a previously uncharacterized connection that causes significant dysregulation. Cross-talk between wild-type or mutant p53 and the m6A readers, writers and erasers has been shown to impact cellular function and induce cancer formation by influencing various cancer hallmarks. Here, this review aims to summarize the complex interplay between the m6A epitranscriptome and p53 signaling pathway, highlighting its effects on tumorigenesis and other hallmarks of cancer, as well as identifying its therapeutic implications for the future.

Predictive model of gene expression regulating invasion and migration of M2 macrophages in breast cancer: clinical prognosis and therapeutic implications

Background

Breast cancer (BRCA) has surpassed lung cancer to become the malignant tumor with the highest incidence in female population. It occurs in malignant cells in breast tissue and is common worldwide. An increasing body of research indicates that M2 macrophages are critical to the occurrence and progression of BRCA. The aim of this work is to build a predictive model of genes related to invasion and migration of M2 macrophages, forecast the prognosis of patients with BRCA, and then evaluate the efficacy of some targeted treatments.

Methods

The Gene Expression Omnibus (GEO; https://www.ncbi.nlm.nih.gov/geo/) database supplied the GSE20685 dataset, whereas the expression profile a clinical details of BRCA patients were obtained from The Cancer Genome Atlas (TCGA; https://portal.gdc.cancer.gov/) database. The genes linked to M2 macrophages and the differentially elevated genes of invasion and migration were found in GSE20685. To explore the prognosis-related invasion and migration M2 macrophage genes, the TCGA-BRCA dataset was merged with Cox regression and least absolute shrinkage and selection operator (LASSO) regression. GSE58812 was utilized for external validation. After calculating each patient's risk score, the prognostic model was examined by analyses of immune infiltration, medication sensitivity, mutation, and enrichment of the risk score.

Results

The risk score had a strong correlation with both several immune cells and popular anti-tumor medications. Additionally, it was discovered that the risk score was a separate prognostic factor for BRCA.

Conclusions

Based on invasion and migration-related M2 macrophage genes, we investigated and validated predictive characteristics in our study that may offer helpful insights into the progression and prognosis of BRCA.

Delineating the mechanistic relevance of the TP53 gene and its mutational impact on gene expression and patients' survival in bladder cancer

Bladder carcinoma (BLCA) is a widespread urological malignancy causing significant global mortality, often hindered by delayed diagnosis and limited treatments. BLCA frequently exhibits TP53 mutations, playing a pivotal role in its pathogenesis and underscoring the potential of targeting TP53 as a therapeutic approach for this prevalent urological malignancy. Tumor tissues from 50 bladder cancer patients were used for mutational analysis in TP53's mutation-rich exons (5, 7, & 8). The gene expression of the TP53 gene, along with a TP53-target gene B-cell translocation gene 2 (BTG2) was also assessed in the cDNA samples from the same BLCA tissues and 15 urine controls of healthy people. The analysis revealed 22 % of patients with somatic hotspot mutations, 18 % with pathogenic missense mutations, and 12 % with intronic variants. Patients with somatic mutations exhibited the worst prognosis, supported by survival analysis from The Cancer Genome Atlas (TCGA) BLCA data. Interestingly, H296Y missense mutation correlated with higher TP53 expression and improved survival, while intronic SNPs were linked to worse outcomes. Additionally, upregulated BTG2 expression in mutated patients was observed which was correlated with poor prognosis, emphasizing the role of TP53 mutations in bladder cancer progression. The multivariate analysis highlighted the predictive power of TP53 mutations, with a high frequency of high-grade tumors (78.57 %) in mutated patients, underscoring their role in cancer progression. In conclusion, this study emphasizes the crucial role of TP53 mutations in bladder cancer patients from Bangladesh.

Emerging small molecular inhibitors as targeted therapies for high-risk acute myeloid leukemias

INTRODUCTION

Acute myeloid leukemia (AML) is an aggressive disease which has traditionally been treated with intensive chemotherapy. Survival in patients with high-risk cytogenetic and molecular subsets has been poor with this approach due to suboptimal responses seen with intensive chemotherapy and due to many patients with higher risk disease being older and unable to tolerate intensive therapies. In recent years, several targeted therapies have been under investigation for patients with high-risk AML subsets.

AREAS COVERED

This review covers four different subsets of high-risk AML including TP53-mutated, KMT2A-rearranged, FLT3-mutated, and secondary AML developing after prior hypomethylating agent exposure. The research discussed in this review focuses on small molecule inhibitors that have been studied in the treatment of these high-risk AML subsets.

EXPERT OPINION

There are several small molecule inhibitors that have demonstrated promise in these high-risk AML subsets. Longer follow-up and ongoing investigation are needed to continue to optimize therapy for patients with high-risk AML.

Somatic alterations of TP53 and MDM2 associated with response to enfortumab vedotin in patients with advanced urothelial cancer

Background

Enfortumab vedotin (EV) is an antibody-drug conjugate approved for patients with treatment-refractory advanced urothelial carcinoma (aUC), however data on biomarkers of response is lacking.

Methods

We retrospectively identified all aUC patients at our institution who received EV monotherapy and had next-generation sequencing (NGS) data available. Patients were considered responders if they had a complete response or partial response on restaging scans during treatment. Observed response rate (ORR) was evaluated by local investigator and compared between responders and non-responders using Chi-squared test. A univariable analysis was conducted using the Cox proportional hazard test to assess for associations between baseline characteristics and most common somatic alterations (in ≥10% of patients) with patient survival outcomes [progression-free survival (PFS) and overall survival (OS)]. Somatic alterations were then individually evaluated in separate multivariate models while accounting for patient and clinical characteristics using Cox regression models.

Results

Among 29 patients treated with EV monotherapy, 27 had available NGS data. Median age was 70, 24 (83%) were men, 19 (62%) were Caucasian, 15 (52%) had pure urothelial histology and 22 (76%) had primary tumor in the bladder. ORR was 41%, and PFS and OS for the overall cohort were 5.1 months and 10.2 months. Responders were enriched among patients with TP53, KDM6A and MDM2 alterations. Patients with these alterations, as well as those with composite TP53/MDM2 alterations (alterations in either TP53 or MDM2), also had increased ORR with EV treatment compared to patients without these alterations. In the univariable analysis, baseline albumin level ≥ 3.0g/dL and presence of composite TP53/MDM2 alterations were associated with a prolonged OS. Baseline ECOG 0/1, TP53 alterations and TP53/MDM2 alterations were associated with a prolonged PFS. In the multivariable analysis, TP53 and TP53/MDM2 alterations were genomic markers predictive of improved PFS after accounting for the relevant clinical characteristics.

Conclusion

In this single-center retrospective analysis of aUC patients treated with EV, presence of TP53 or MDM2 somatic alterations, lower ECOG PS scores (ECOG 0 or 1) and higher albumin levels (≥3 g/dL) were associated with improved outcomes with EV treatment. Prospective and external validation of these findings in larger cohorts is warranted.

Outcomes in Patients with Poor-Risk Cytogenetics with or without TP53 Mutations Treated with Venetoclax and Azacitidine

PURPOSE

To evaluate efficacy and safety of venetoclax + azacitidine in treatment-naïve patients with acute myeloid leukemia harboring poor-risk cytogenetics and TP53mut or TP53wt.

PATIENTS AND METHODS

We analyzed data from a phase III study (NCT02993523) comparing venetoclax (400 mg orally days 1-28) + azacitidine (75 mg/m2 days 1-7) or placebo + azacitidine, and from a phase Ib study (NCT02203773) of venetoclax + azacitidine. Patients were ineligible for intensive therapy. TP53 status was analyzed centrally; cytogenetic studies were performed locally.

RESULTS

Patients (n = 127) with poor-risk cytogenetics receiving venetoclax + azacitidine (TP53wt = 50; TP53mut = 54) were compared with patients with poor-risk cytogenetics (n = 56) receiving azacitidine alone (TP53wt = 22; TP53mut = 18).For poor-risk cytogenetics + TP53wt patients, venetoclax + azacitidine versus azacitidine alone resulted in composite remission rates (CRc) of 70% versus 23%, median duration of remission (DoR) of 18.4 versus 8.5 months, and median overall survival (OS) of 23.4 versus 11.3 months, respectively. Outcomes with venetoclax + azacitidine were comparable with similarly treated patients with intermediate-risk cytogenetics and TP53wt.For poor-risk cytogenetics + TP53mut patients, venetoclax + azacitidine versus azacitidine alone resulted in CRc of 41% versus 17%, median DoR of 6.5 versus 6.7 months, and median OS of 5.2 versus 4.9 months, respectively.For poor-risk cytogenetics + TP53mut patients, predominant grade ≥3 adverse events (AE) for venetoclax + azacitidine versus azacitidine were febrile neutropenia (55%/39%), thrombocytopenia (28%/28%), neutropenia (26%/17%), anemia (13%/6%), and pneumonia (28%/33%). AEs were comparable between TP53mut and TP53wt patients.

CONCLUSIONS

In poor-risk cytogenetics + TP53mut patients, venetoclax + azacitidine improved remission rates but not DoR or OS compared with azacitidine alone. However, in poor-risk cytogenetics + TP53wt patients, venetoclax + azacitidine resulted in higher remission rates and longer DoR and OS than azacitidine alone, with outcomes comparable with similarly treated patients with intermediate-risk cytogenetics. Toxicities were similar in TP53mut and TP53wt patients. See related commentary by Green and Zeidner, p. 5235.

DNAJA1- and conformational mutant p53-dependent inhibition of cancer cell migration by a novel compound identified through a virtual screen

Cancers are frequently addicted to oncogenic missense mutant p53 (mutp53). DNAJA1, a member of heat shock protein 40 (HSP40), also known as J-domain proteins (JDPs), plays a crucial role in the stabilization and oncogenic activity of misfolded or conformational mutp53 by binding to and preventing mutp53 from proteasomal degradation. However, strategies to deplete mutp53 are not well-established, and no HSP40/JDPs inhibitors are clinically available. To identify compounds that bind to DNAJA1 and induce mutp53 degradation, we performed an in silico docking study of ~10 million of compounds from the ZINC database for the J-domain of DNAJA1. A compound 7-3 was identified, and its analogue A11 effectively reduced the levels of DNAJA1 and conformational mutp53 with minimal effects on the levels of wild-type p53 and DNA-contact mutp53. A11 suppressed migration and filopodia formation in a manner dependent on DNAJA1 and conformational mutp53. A mutant DNAJA1 with alanine mutations at predicted amino acids (tyrosine 7, lysine 44, and glutamine 47) failed to bind to A11. Cells expressing the mutant DNAJA1 became insensitive to A11-mediated depletion of DNAJA1 and mutp53 as well as A11-mediated inhibition of cell migration. Thus, A11 is the first HSP40/JDP inhibitor that has not been previously characterized for depleting DNAJA1 and subsequently conformational mutp53, leading to inhibition of cancer cell migration. A11 can be exploited for a novel treatment against cancers expressing conformational mutp53.

Anti-cancer properties of Caulerpa racemosa by altering expression of Bcl-2, BAX, cleaved caspase 3 and apoptosis in HeLa cancer cell culture

The main cause of cervical cancer is infection with Human Papilloma Virus (HPV). Loss of apoptotic control allows cancer cells to survive longer and allows time for mutation accumulation thereby increasing the ability to invade during tumor development. Treatment options for cervical cancer today are surgery, radiotherapy, and chemotherapy. Toxicity to normal cells, adverse side effects, and drug resistance are the main barriers to the use of chemotherapy. Among marine organisms such as bacteria, fungi, actinobacteria, and seaweed have been used for the treatment of cancer. Caulerpa has bioactive metabolites, namely alkaloids, terpenoids, flavonoids, steroids and tannins and its bioactivity has been reported against many diseases including cancer. This study aimed to evaluate the anticancer activity of C. racemosa on HeLa cervical cancer cells. The study used a true experimental post-test only control group design to determine the effect of C. racemosa extract on HeLa cancer cells. C. racemosa extract was given in doses of 50 μg/mL, 100 μg/mL, 200 μg/mL, and 0 μg/mL as controls. Quantitative measurement of apoptosis was measured using flowcytometry and the expression of Bcl-2, BAX, and cleaved-caspase 3 as pro and anti-apoptotic proteins was measured using immunofluorescence. Trypan blue exclusion test was performed to measure cell viability. C. racemosa extract significantly increased the expression of pro-apoptotic proteins BAX and cleaved caspase-3 compared to controls. Annexin V-PI analysis showed the induction of apoptosis in treated cells and decreased HeLa cell viability at 24 hours and 48 hours post-treatment (p-value <0.05). C. racemosa extract has potential as an anti-cancer with pro-apoptotic and anti-proliferative activity on HeLa cancer cells and can be explored further as a cervical cancer therapy.

How Genetics Can Drive Initial Therapy Choices for Older Patients with Acute Myeloid Leukemia

OPINION STATEMENT

Treatment of older adults with acute myeloid leukemia (AML) is challenging. Therapy decisions must be guided by multiple factors including aging-related conditions (e.g., comorbidities, functional impairment), therapy benefits and risks, patient preferences, and disease characteristics. Balancing these factors requires understanding the unique, and frequently higher-risk cytogenetic and molecular characteristics of AML in older adult populations, which should caution providers not to reduce therapy intensity on the basis of age alone. Instead, geriatric assessments should be employed to determine fitness for therapy. Treatment options in AML are increasingly targeted to specific mutations or recognized to have differential benefits on the basis of genomics, and representation of older adults and geriatric outcome reporting in clinical trials is improving. Additionally, newer studies have begun to explore personalized therapy strategies on the basis of initial genetic testing. Review and refinement of practice guidelines for older patients on the basis of these advances is needed and is anticipated to remain an important topic in ongoing hematology/oncology clinical education.

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.

Signaling Pathways and Natural Compounds in Triple-Negative Breast Cancer Cell Line

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, having a poor prognosis and rapid metastases. TNBC is characterized by the absence of estrogen, progesterone, and human epidermal growth receptor-2 (HER2) expressions and has a five-year survival rate. Compared to other breast cancer subtypes, TNBC patients only respond to conventional chemotherapies, and even then, with limited success. Shortages of chemotherapeutic medication can lead to resistance, pressured index therapy, non-selectivity, and severe adverse effects. Finding targeted treatments for TNBC is difficult owing to the various features of cancer. Hence, identifying the most effective molecular targets in TNBC pathogenesis is essential for predicting response to targeted therapies and preventing TNBC cell metastases. Nowadays, natural compounds have gained attention as TNBC treatments, and have offered new strategies for solving drug resistance. Here, we report a systematic review using the database from Pubmed, Science Direct, MDPI, BioScince, Springer, and Nature for articles screening from 2003 to 2022. This review analyzes relevant signaling pathways and the prospect of utilizing natural compounds as a therapeutic agent to improve TNBC treatments in the future.

Pathway-specific effects of ADSL deficiency on neurodevelopment

Adenylosuccinate lyase (ADSL) functions in de novo purine synthesis (DNPS) and the purine nucleotide cycle. ADSL deficiency (ADSLD) causes numerous neurodevelopmental pathologies, including microcephaly and autism spectrum disorder. ADSLD patients have normal serum purine nucleotide levels but exhibit accumulation of dephosphorylated ADSL substrates, S-Ado, and SAICAr, the latter being implicated in neurotoxic effects through unknown mechanisms. We examined the phenotypic effects of ADSL depletion in human cells and their relation to phenotypic outcomes. Using specific interventions to compensate for reduced purine levels or modulate SAICAr accumulation, we found that diminished AMP levels resulted in increased DNA damage signaling and cell cycle delays, while primary ciliogenesis was impaired specifically by loss of ADSL or administration of SAICAr. ADSL-deficient chicken and zebrafish embryos displayed impaired neurogenesis and microcephaly. Neuroprogenitor attrition in zebrafish embryos was rescued by pharmacological inhibition of DNPS, but not increased nucleotide concentration. Zebrafish also displayed phenotypes commonly linked to ciliopathies. Our results suggest that both reduced purine levels and impaired DNPS contribute to neurodevelopmental pathology in ADSLD and that defective ciliogenesis may influence the ADSLD phenotypic spectrum.

Regulation of p53 and Cancer Signaling by Heat Shock Protein 40/J-Domain Protein Family Members

Heat shock proteins (HSPs) are molecular chaperones that assist diverse cellular activities including protein folding, intracellular transportation, assembly or disassembly of protein complexes, and stabilization or degradation of misfolded or aggregated proteins. HSP40, also known as J-domain proteins (JDPs), is the largest family with over fifty members and contains highly conserved J domains responsible for binding to HSP70 and stimulation of the ATPase activity as a co-chaperone. Tumor suppressor p53 (p53), the most frequently mutated gene in human cancers, is one of the proteins that functionally interact with HSP40/JDPs. The majority of p53 mutations are missense mutations, resulting in acquirement of unexpected oncogenic activities, referred to as gain of function (GOF), in addition to loss of the tumor suppressive function. Moreover, stability and levels of wild-type p53 (wtp53) and mutant p53 (mutp53) are crucial for their tumor suppressive and oncogenic activities, respectively. However, the regulatory mechanisms of wtp53 and mutp53 are not fully understood. Accumulating reports demonstrate regulation of wtp53 and mutp53 levels and/or activities by HSP40/JDPs. Here, we summarize updated knowledge related to the link of HSP40/JDPs with p53 and cancer signaling to improve our understanding of the regulation of tumor suppressive wtp53 and oncogenic mutp53 GOF activities.

Genomic and Transcriptomic Profiling of Brain Metastases

Simple Summary

Brain metastases (BM) are the most common brain tumors in adults and are the main cause of cancer-associated death. Omics analysis of BM will allow for a better understanding of metastatic progression, prognosis and therapeutic targeting. In this study, BM samples underwent comprehensive molecular profiling with genomics and transcriptomics. Mutational signatures suggested that most mutations were gained prior to metastasis. A novel copy number event centered around the MCL1 gene was found in 75% of all samples. Transcriptomics revealed that melanoma BM formed a distinct cluster in comparison to other subtypes. Poor survival correlated to self-identified black race and absence of radiation treatment but not molecular profiles. These data identify potential new drivers of brain metastatic progression, implicate that melanoma BM are distinctive and likely responsive to unique therapies, and further investigation of sociodemographic and clinical features are needed in BM cohorts.

Abstract

Brain metastases (BM) are the most common brain tumors in adults occurring in up to 40% of all cancer patients. Multi-omics approaches allow for understanding molecular mechanisms and identification of markers with prognostic significance. In this study, we profile 130 BM using genomics and transcriptomics and correlate molecular characteristics to clinical parameters. The most common tumor origins for BM were lung (40%) followed by melanoma (21%) and breast (15%). Melanoma and lung BMs contained more deleterious mutations than other subtypes (p < 0.001). Mutational signatures suggested that the bulk of the mutations were gained before metastasis. A novel copy number event centered around the MCL1 gene was found in 75% of all samples, suggesting a broader role in promoting metastasis. Unsupervised hierarchical cluster analysis of transcriptional signatures available in 65 samples based on the hallmarks of cancer revealed four distinct clusters. Melanoma samples formed a distinctive cluster in comparison to other BM subtypes. Characteristics of molecular profiles did not correlate with survival. However, patients with self-identified black race or those who did not receive radiation correlated with poor survival. These data identify potential new drivers of brain metastatic progression. Our data also suggest further investigation of sociodemographic and clinical features is needed in BM cohorts.

Clinical significance of CCN5 and mutant p53 in primary and recurrent lesions of breast cancer

OBJECTIVE

To analyze the expression and significance of CCN5 and mutant p53 proteins in primary and recurrent lesions of breast cancer (BC) patients.

METHODS

The expression of CCN5 and mutant p53 proteins in 20 normal breast tissues, 60 primary and chest wall recurrent lesions were detected by streptavidin peroxidase conjugated (SP) method.

RESULTS

The differences in CCN5 and mutant p53 expression is significant among normal breast tissue, primary lesion, and recurrent lesions (Χ²=18.380 and Χ²=30.549, P < 0.05), and the expression of CCN5 protein was higher and the expression of mutant p53 protein was lower in all primary lesions than in recurrent lesions (P < 0.05). CCN5 expression was higher in the group without lymph node metastasis (LNM) than in the group with LNM in BC patients, while mutant p53 protein expression was higher in the group with LNM than in the group without LNM (Χ²=9.775, Χ²=7.102, P < 0.05). There was a negative relationship between CCN5 and mutant p53 protein expression in BC tissues (r_p=-0.013, P < 0.001).

CONCLUSION

CCN5, mutant p53 protein expression may play different regulatory roles in BC recurrence and LNM and have important implications in BC development and prognosis.

Mutations of key driver genes in gastric cancer metastasis risk: a systematic review and meta-analysis

Objective: Associations between gene mutations and metastasis in gastric cancer (GC) remain contradictory, resulting in the inaccurate estimation of the magnitude of the risk associated with specific genotypes.Methods: In this study, we first screened out four key driver genes (TP53, PIK3CA, APC and ARID1A) by jointly analyzing the mutation levels and searching the literature for genes associated with GC metastasis. We then performed a meta-analysis to demonstrate the relationship between these key driver gene mutations and GC metastasis, including lymphatic and distance metastasis.Results: We found out four key driver genes (TP53, PIK3CA, APC and ARID1A), associated with risk of GC metastasis. The results showed that TP53 (OR 1.39, 95% CI 1.12-1.72) and APC mutations (OR 0.58, 95% CI 0.38-0.89) were associated with lymph node metastasis and distant metastasis in GC. And TP53 mutations (OR 1.65, 95% CI 1.25-2.18) were significantly related to GC metastasis in the Asian population. APC mutations (OR 0.54, 95% CI 0.29-1.00) were also related to GC metastasis in the European and American populations. There was no significant association with GC metastasis in PIK3CA or ARID1A mutations.Expert opinion:Mutations of TP53 and APC play important roles in lymph node metastasis and distant metastasis of GC and may be potential important biomarkers of progression and therapeutic targets. These observations should be further prospectively verified.

The Gain-of-Function p53 R248W Mutant Promotes Migration by STAT3 Deregulation in Human Pancreatic Cancer Cells

Missense p53 mutations (mutp53) occur in approx. 70% of pancreatic ductal adenocarcinomas (PDAC). Typically, mutp53 proteins are aberrantly stabilized by Hsp90/Hsp70/Hsp40 chaperone complexes. Notably, stabilization is a precondition for specific mutp53 alleles to acquire powerful neomorphic oncogenic gain-of-functions (GOFs) that promote tumor progression in solid cancers mainly by increasing invasion and metastasis. In colorectal cancer (CRC), we recently established that the common hotspot mutants mutp53^R248Q and mutp53^R248W exert GOF activities by constitutively binding to and hyperactivating STAT3. This results in increased proliferation and invasion in an autochthonous CRC mouse model and correlates with poor survival in patients. Comparing a panel of p53 missense mutations in a series of homozygous human PDAC cell lines, we show here that, similar to CRC, the mutp53^R248W protein again undergoes a strong Hsp90-mediated stabilization and selectively promotes migration. Highly stabilized mutp53 is degradable by the Hsp90 inhibitors Onalespib and Ganetespib, and correlates with growth suppression, possibly suggesting therapeutic vulnerabilities to target GOF mutp53 proteins in PDAC. In response to mutp53 depletion, only mutp53^R248W harboring PDAC cells show STAT3 de-phosphorylation and reduced migration, again suggesting an allele-specific GOF in this cancer entity, similar to CRC. Moreover, mutp53^R248W also exhibits the strongest constitutive complex formation with phosphorylated STAT3. The selective mutp53^R248W GOF signals through enhancing the STAT3 axis, which was confirmed since targeting STAT3 by knockdown or pharmacological inhibition phenocopied mutp53 depletion and reduced cell viability and migration preferentially in mutp53^R248W-containing PDAC cells. Our results confirm that mutp53 GOF activities are allele specific and can span across tumor entities.

Differential chromatin accessibility landscape of gain-of-function mutant p53 tumours

BACKGROUND

Mutations in TP53 not only affect its tumour suppressor activity but also exerts oncogenic gain-of-function activity. While the genome-wide mutant p53 binding sites have been identified in cancer cell lines, the chromatin accessibility landscape driven by mutant p53 in primary tumours is unknown. Here, we leveraged the chromatin accessibility data of primary tumours from The Cancer Genome Atlas (TCGA) to identify differentially accessible regions in mutant p53 tumours compared to wild-type p53 tumours, especially in breast and colon cancers.

RESULTS

We identified 1587 lost and 984 gained accessible chromatin regions in breast, and 1143 lost and 640 gained regions in colon cancers. However, only less than half of those regions in both cancer types contain sequence motifs for wild-type or mutant p53 binding. Whereas, the remaining showed enrichment for master transcriptional regulators, such as FOX-Family TFs and NF-kB in lost and SMAD and KLF TFs in gained regions of breast. In colon, ATF3 and FOS/JUN TFs were enriched in lost, and CDX family TFs and HNF4A in gained regions. By integrating the gene expression data, we identified known and novel target genes regulated by the mutant p53.

CONCLUSION

This study reveals the direct and indirect mechanisms by which gain-of-function mutant p53 targets the chromatin and subsequent gene expression patterns in a tumour-type specific manner. This furthers our understanding of the impact of mutant p53 in cancer development.

Significance of TP53 Mutation in Cellular Process and Disease Progression in Lung Adenocarcinoma

Introduction: TP53 (tumor protein p53) is one of the most commonly mutanted genes in lung adenocarcinoma (LUAD). Materials and Methods: In this study, we used data from The Cancer Genome Atlas (TCGA) to evaluate the importance of TP53 mutations in cellular processes, disease progression, the prognosis in LUAD, and to identify critical hub genes and pathways associated with oncogenesis. Results: Analysis of the TCGA data showed TP53 mutations in 22% of LUAD patients. Clinicopathological analyses demonstrated that TP53 mutation was correlated with the disease progression but not prognosis. We identified 1935 differentially expressed genes (DEGs). Functional enrichment analysis showed that the DEGs were mainly concentrated in metabolism, cell differentiation, and cancer-related pathways. The top hub genes were identified and disease analysis revealed the most critical genes related to disease progression and prognosis. The expression levels of several of these genes were then tested in tumor tissues. Conclusion: Our results showed that TP53 mutation plays a critical role in cellular process and the clinicopathological findings in LUAD. We also identified potential key genes, which could provide novel evidence for individualized treatment.

TP53 Mutations in Acute Myeloid Leukemia: Still a Daunting Challenge?

TP53 is a key tumor suppressor gene with protean functions associated with preservation of genomic balance, including regulation of cellular senescence, apoptotic pathways, metabolism functions, and DNA repair. The vast majority of de novo acute myeloid leukemia (AML) present unaltered TP53 alleles. However, TP53 mutations are frequently detected in AML related to an increased genomic instability, such as therapy‐related (t-AML) or AML with myelodysplasia-related changes. Of note, TP53 mutations are associated with complex cytogenetic abnormalities, advanced age, chemoresistance, and poor outcomes. Recent breakthroughs in AML research and the development of targeted drugs directed at specific mutations have led to an explosion of novel treatments with different mechanisms. However, optimal treatment strategy for patients harboring TP53 mutations remains a critical area of unmet need. In this review, we focus on the incidence and clinical significance of TP53 mutations in de novo and t-AML. The influence of these alterations on response and clinical outcomes as well as the current and future therapeutic perspectives for this hardly treatable setting are discussed.

The oncogenicity of tumor-derived mutant p53 is enhanced by the recruitment of PLK3

p53 mutations with single amino acid changes in cancer often lead to dominant oncogenic changes. Here, we have developed a mouse model of gain-of-function (GOF) p53-driven lung cancer utilizing conditionally active LSL p53-R172H and LSL K-Ras-G12D knock-in alleles that can be activated by Cre in lung club cells. Mutation of the p53 transactivation domain (TAD) (p53-L25Q/W26S/R172H) eliminating significant transactivation activity resulted in loss of tumorigenicity, demonstrating that transactivation mediated by or dependent on TAD is required for oncogenicity by GOF p53. GOF p53 TAD mutations significantly reduce phosphorylation of nearby p53 serine 20 (S20), which is a target for PLK3 phosphorylation. Knocking out PLK3 attenuated S20 phosphorylation along with transactivation and oncogenicity by GOF p53, indicating that GOF p53 exploits PLK3 to trigger its transactivation capability and exert oncogenic functions. Our data show a mechanistic involvement of PLK3 in mutant p53 pathway of oncogenesis.

The mechanisms of how gain-of-function (GOF) mutant p53 drives carcinogenesis are unclear. Here, the authors show that a GOF mutant p53 requires its transactivation capability to induce mouse lung tumors and this is dependent on PLK3 phosphorylation of GOF mutant p53.

Mutant TP53 interacts with BCAR1 to contribute to cancer cell invasion

BACKGROUND

Mutant TP53 interacts with other proteins to produce gain-of-function properties that contribute to cancer metastasis. However, the underlying mechanisms are still not fully understood.

METHODS

Using immunoprecipitation and proximity ligation assays, we evaluated breast cancer anti-estrogen resistance 1 (BCAR1) as a novel binding partner of TP53R273H, a TP53 mutant frequently found in human cancers. The biological functions of their binding were examined by the transwell invasion assay. Clinical outcome of patients was analysed based on TP53 status and BCAR1 expression using public database.

RESULTS

We discovered a novel interaction between TP53R273H and BCAR1. We found that BCAR1 translocates from the cytoplasm into the nucleus and binds to TP53R273H in a manner dependent on SRC family kinases (SFKs), which are known to enhance metastasis. The expression of full-length TP53R273H, but not the BCAR1 binding-deficient mutant TP53R273HΔ102-207, promoted cancer cell invasion. Furthermore, among the patients with mutant TP53, high BCAR1 expression was associated with a poorer prognosis.

CONCLUSIONS

The interaction between TP53R273H and BCAR1 plays an important role in enhancing cancer cell invasion. Thus, our study suggests a disruption of the TP53R273H-BCAR1 binding as a potential therapeutic approach for TP53R273H-harbouring cancer patients.

HPV-inactive cell populations arise from HPV16-transformed human keratinocytes after p53 knockout

HPV-inactive head and neck and cervical cancers contain HPV DNA but do not express HPV E6/E7. HPV-positive primary head and neck tumors usually express E6/E7, however they may produce HPV-inactive metastases. These observations led to our hypothesis that HPV-inactive cancers begin as HPV-active lesions, losing dependence on E6/E7 expression during progression. Because HPV-inactive cervical cancers often have mutated p53, we investigated whether p53 loss may play a role in the genesis of HPV-inactive cancers. p53 knockout (p53-KO) by CRISPR-Cas9 resulted in a 5-fold reduction of E7 mRNA in differentiation-resistant HPV16 immortalized human keratinocytes (HKc/DR). E7 expression was restored by 5-Aza-2 deoxycytidine in p53 KO lines, suggesting a role of DNA methylation in this process. In-situ hybridization showed that p53 KO lines consist of mixed populations of E6/E7-positive and negative cells. Hence, loss of p53 predisposes HPV16 transformed cells to losing dependence on the continuous expression of HPV oncogenes for proliferation.

Human papillomavirus type 38 alters wild-type p53 activity to promote cell proliferation via the downregulation of integrin alpha 1 expression

Tumor suppressors can exert pro-proliferation functions in specific contexts. In the beta human papillomavirus type 38 (HPV38) experimental model, the viral proteins E6 and E7 promote accumulation of a wild-type (WT) p53 form in human keratinocytes (HKs), promoting cellular proliferation. Inactivation of p53 by different means strongly decreases the proliferation of HPV38 E6/E7 HKs. This p53 form is phosphorylated at S392 by the double-stranded RNA-dependent protein kinase PKR, which is highly activated by HPV38. PKR-mediated S392 p53 phosphorylation promotes the formation of a p53/DNMT1 complex, which inhibits expression of integrin alpha 1 (ITGA1), a repressor of epidermal growth factor receptor (EGFR) signaling. Ectopic expression of ITGA1 in HPV38 E6/E7 HKs promotes EGFR degradation, inhibition of cellular proliferation, and cellular death. Itga1 expression was also inhibited in the skin of HPV38 transgenic mice that have an elevated susceptibility to UV-induced skin carcinogenesis. In summary, these findings reveal the existence of a specific WT p53 form that displays pro-proliferation properties.

Establishment of a prognostic model for predicting short-term disease-free survival in cases of hepatitis B-related hepatocellular carcinoma with the TP53 249Ser mutation in southern China

Background

Hepatitis B virus (HBV) infection and dietary aflatoxin exposure are two major and synergistic carcinogenic factors of hepatocellular carcinoma (HCC) in southern China. Mutation of the TP53 gene at codon 249 (TP53 249Ser) is recognized as a fingerprint of aflatoxin B1 (AFB1) exposure.

Methods

A total of 485 HCC patients positive for serum hepatitis B surface antigen were enrolled. The clinicopathological information and survival time were collected. TP53 249Ser mutations in HCC were detected by Sanger DNA sequencing after PCR amplification. Immunohistochemical staining was used to evaluate TP53 expression. Propensity score matching (PSM) and Cox proportional hazards regression (CPHR) were conducted to identify independent risk factors for prognosis that were incorporated into the nomogram. Univariate logistic regression analysis was used to compare differences in clinical factors between the TP53 249Ser mutation group and the non-mutation group. A Kaplan-Meier plot, univariate and multivariate Cox proportional hazards models were used to assess the association between clinicopathological characteristics and survival outcomes.

Results

After PSM, a total of 322 cases were included in the analysis of clinical prognosis. Results of CPHR showed that the mutation group had a relatively higher risk of tumor recurrence within 2 years after undergoing hepatectomy (P=0.039, HR =1.47, 95% CI: 1.02–2.18). The prognostic model performed better in terms of 2-year DFS prediction than BCLC stage. Patients who had a nomogram score of more than 160 were considered to have a higher risk of recurrence within 2 years.

Conclusions

Our study found that the TP53 249Ser mutation may be a high risk factor of HBV-related HCC recurrence in the short term. And we initially established a nomogram scoring system for predicting 2-year recurrence in HBV-related HCC patients in southern China.

Significance of tumor protein p53 mutation in cellular process and drug selection in brain lower grade (WHO grades II and III) glioma

Aim: Tumor protein p53 (TP53) mutant is one of the most frequently mutated genes in glioma. Results: The Cancer Genome Atlas data has shown that TP53 mutation is present in 49% of lower grade (World Health Organization [WHO] grades II and III) glioma patients. Data from The Genomics of Drug Sensitivity in Cancer database showed that three drugs: (5Z)-7-oxozeaenol, dabrafenib and nutlin-3a (-), have shown more resistance in patients with TP53 mutation. We identified 1100 differentially expressed genes. Functional enrichment analysis showed that the differentially expressed genes are mainly concentrated in the transport of ionic and cancer-related pathways. The top ten hub genes were identified and an outcome analysis revealed the most critical genes related to prognosis. Conclusion: Our results identified the key genes and pathways that might provide the basic proof to improve individualized treatment in patients with glioma.

Demethylase-independent function of JMJD2D as a novel antagonist of p53 to promote Liver Cancer initiation and progression

Background: As a histone demethylase, JMJD2D can enhance gene expression by specifically demethylating H3K9me2/3 and plays an important role in promoting colorectal cancer progression. However, its role in liver cancer remains unclear.

Methods: The expression of JMJD2D was examined in human liver cancer specimens and non-tumorous liver tissues by immunohistochemical or immunoblot analysis. JMJD2D expression was knocked down in liver cancer cells using small hairpin RNAs, and cells were analyzed with Western blot, real-time PCR, cell viability, colony formation, and flow cytometry assays. Cells were also grown as tumor xenografts in nude mice, and the tumor cell proliferation and apoptosis were measured by immunohistochemical analysis. The relationship between JMJD2D and p53 was studied by co-immunoprecipitation, chromatin immunoprecipitation, and electric mobility shift assay. Wild-type and JMJD2D-knockout mice were intraperitoneally injected with diethylnitrosamine (DEN) to induce liver tumors and the liver cancer initiation and progression were investigated.

Results: JMJD2D was frequently upregulated in human liver cancer specimens compared with non-tumorous liver tissues. The overall survival of liver cancer patients with high JMJD2D expression was significantly decreased compared to that with low JMJD2D expression. JMJD2D knockdown reduced liver cancer cell proliferation and xenograft tumor growth, sensitized cells to chemotherapeutic drug-induced apoptosis, and increased the expression of cell cycle inhibitor p21 and pro-apoptosis gene PUMA. Genetically, JMJD2D deficiency protected mice against DEN-induced liver cancer initiation and progression. Knockout of tumor suppressor p53 significantly reduced the effects of JMJD2D knockdown on cell proliferation, apoptosis, and the expression of p21 and PUMA, suggesting that JMJD2D regulates liver cancer cell functions in part through inhibiting p53 signaling pathway. Mechanistically, JMJD2D directly interacted with p53 and inhibited p53 recruitment to the p21 and PUMA promoters in a demethylation activity-independent manner, implicating a demethylase-independent function of JMJD2D as a novel p53 antagonist. In addition, JMJD2D could activate Wnt/β-catenin signaling to promote liver cancer cell proliferation.

Conclusion: Our study demonstrates that JMJD2D can antagonize the tumor suppressor p53 and activate an oncogenic signaling pathway (such as Wnt/β-catenin signaling pathway) simultaneously to promote liver cancer initiation and progression, suggesting that JMJD2D may serve as a novel target for liver cancer treatment.

Upregulation of fibronectin following loss of p53 function is a poor prognostic factor in ovarian carcinoma with a unique immunophenotype

Background

We previously demonstrated that ovarian high grade serous carcinomas (OHGSeCa) and ovarian clear cell carcinomas (OCCCa) with an HNF-1β+/p53+/ARID1A+ immunophenotype were associated with the worst unfavorable prognosis. To clarify the molecular mechanisms underlying this finding, we focused on alterations in the p53 signaling pathway in these tumors.

Methods

Changes in cell phenotype and function following knockdown of wild-type p53 (p53-KD) were assessed using OCCCa cells expressing endogenous HNF-1β and ARID1A. The prognostic significance of molecules that were deregulated following p53-KD was also examined using 129 OCCCa/OHGSeCa cases.

Results

p53-KD cells had increased expression of Snail, phospho-Akt (pAkt), and pGSK3β, and decreased E-cadherin expression, leading to epithelial-mesenchymal transition (EMT)/cancer stem cell (CSC) features. The cells also exhibited acceleration of cell motility and inhibition of cell proliferation and apoptosis. Next generation sequencing revealed that fibronectin (FN) expression was significantly increased in the p53 KD-cells, in line with our observation that wild-type p53 (but not mutant p53) repressed FN1 promoter activity. In addition, treatment of OCCCa cells with FN significantly increased cell migration capacity and decreased cell proliferation rate, independent of induction of EMT features. In clinical samples, FN/p53 scores were significantly higher in OCCCa/OHGSeCa with the HNF-1β+/p53+/ARID1A+ immunophenotype when compared to others. Moreover, high FN/high p53 expression was associated with the worst overall survival and progression-free survival in OCCCa/OHGSeCa patients.

Conclusion

These findings suggest that upregulation of FN following loss of p53 function may impact the biological behavior of OCCCa/OHGSeCa, particularly in tumors with an HNF-1β+/p53+/ARID1A+ immunophenotype, through alterations in cell mobility and cell proliferation. The accompanying induction of EMT/CSC properties and inhibition of apoptosis due to p53 abnormalities also contribute to the establishment and maintenance of tumor phenotypic characteristics.

CDK1 and CDC20 overexpression in patients with colorectal cancer are associated with poor prognosis: evidence from integrated bioinformatics analysis

BACKGROUND

Colorectal cancer (CRC) is one of the most common malignancies of the digestive system, which causes severe financial burden worldwide. However, the specific mechanisms involved in CRC are still unclear.

METHODS

To identify the significant genes and pathways involved in the initiation and progression of CRC, the microarray dataset GSE126092 was downloaded from Gene Expression Omnibus (GEO) database, and then, the data was analyzed to identify differentially expressed genes (DEGs). Subsequently, the Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed on these DEGs using the DAVID database, and the protein-protein interaction (PPI) network was constructed using the STRING database and analyzed using the Cytoscape software. Finally, hub genes were screened, and the survival analysis was performed on these hub genes using the Kaplan-Meier curves in the cBioPortal database.

RESULTS

In total, 937 DEGs were obtained, including 316 upregulated genes and 621 downregulated genes. GO analysis revealed that the DEGs were mostly enriched in terms of nuclear division, organelle fission, cell division, and cell cycle process. KEGG pathway analysis showed that the DEGs were mostly enriched in cell cycle, oocyte meiosis, cytokine-cytokine receptor interaction, and cGMP-PKG signaling pathway. The PPI network comprised 608 nodes and 3100 edges, and 4 significant modules and 10 hub genes with the highest degree were identified using the Cytoscape software. Finally, survival analysis showed that overexpression of CDK1 and CDC20 in patients with CRC were statistically associated with worse overall survival.

CONCLUSIONS

This bioinformatics analysis revealed that CDK1 and CDC20 might be candidate targets for diagnosis and treatment of CRC, which provided valuable clues for CRC.

Proteogenomic Characterization of Endometrial Carcinoma

We undertook a comprehensive proteogenomic characterization of 95 prospectively collected endometrial carcinomas, comprising 83 endometrioid and 12 serous tumors. This analysis revealed possible new consequences of perturbations to the p53 and Wnt/β-catenin pathways, identified a potential role for circRNAs in the epithelial-mesenchymal transition, and provided new information about proteomic markers of clinical and genomic tumor subgroups, including relationships to known druggable pathways. An extensive genome-wide acetylation survey yielded insights into regulatory mechanisms linking Wnt signaling and histone acetylation. We also characterized aspects of the tumor immune landscape, including immunogenic alterations, neoantigens, common cancer/testis antigens, and the immune microenvironment, all of which can inform immunotherapy decisions. Collectively, our multi-omic analyses provide a valuable resource for researchers and clinicians, identify new molecular associations of potential mechanistic significance in the development of endometrial cancers, and suggest novel approaches for identifying potential therapeutic targets.

HOPS/TMUB1 retains p53 in the cytoplasm and sustains p53-dependent mitochondrial apoptosis

Apoptotic signalling by p53 occurs at both transcriptional and non-transcriptional levels, as p53 may act as a direct apoptogenic stimulus via activation of the intrinsic mitochondrial pathway. HOPS is a highly conserved, ubiquitously expressed shuttling protein with an ubiquitin-like domain. We generated Hops-/- mice and observed that they are viable with no apparent phenotypic defects. However, when treated with chemotherapeutic agents, Hops-/- mice display a significant reduction in apoptosis, suggesting an impaired ability to respond to genotoxic stressors. We show that HOPS acts as a regulator of cytoplasmic p53 levels and function. By binding p53, HOPS inhibits p53 proteasomal degradation and favours p53 recruitment to mitochondria and apoptosis induction. By interfering with importin α, HOPS further increases p53 cytoplasmic levels. Thus, HOPS promotes the p53-dependent mitochondrial apoptosis pathway by preserving cytoplasmic p53 from both degradation and nuclear uptake.

Significance of TP53 mutation in bladder cancer disease progression and drug selection

BACKGROUND

The tumor protein p53 (TP53) mutant is one of the most frequent mutant genes in bladder cancer. In this study, we assessed the importance of the TP53 mutation in bladder cancer progression and drug selection, and identified potential pathways and core genes associated with the underlying mechanisms.

METHODS

Gene expression data used in this study were downloaded from The Cancer Genome Atlas and cBioportal databases. Drug sensitivity data were obtained from the Genomics of Drug Sensitivity in Cancer. We did functional enrichment analysis by gene set enrichment analysis (GSEA) and the Database for Annotation, Visualization and Integrated Discovery (DAVID).

RESULTS

We found the TP53 mutation in 50% of bladder cancer patients. Patients with the TP53 mutation were associated with a lower TP53 mRNA expression level, more advanced tumor stage and higher histologic grade. Three drugs, mitomycin-C, doxorubicin and gemcitabine, were especially more sensitive to bladder cancer with the TP53 mutation. As for the mechanisms, we identified 863 differentially expressed genes (DEGs). Functional enrichment analysis suggested that DEGs were primarily enriched in multiple metabolic progressions, chemical carcinogenesis and cancer related pathways. The protein-protein interaction network identified the top 10 hub genes. Our results have suggested the significance of TP53 mutation in disease progression and drug selection in bladder cancer, and identified multiple genes and pathways related in such program, offering novel basis for bladder cancer individualized treatment.

EFTUD2 gene deficiency disrupts osteoblast maturation and inhibits chondrocyte differentiation via activation of the p53 signaling pathway

Background

Mandibulofacial dysostosis with microcephaly (MFDM) is characteristic of multiple skeletal anomalies comprising craniofacial anomalies/dysplasia, microcephaly, dysplastic ears, choanal atresia, and short stature. Heterozygous loss of function variants of EFTUD2 was previously reported in MFDM; however, the mechanism underlying EFTUD2-associated skeletal dysplasia remains unclear.

Results

We identified a novel frameshift variant of EFTUD2 (c.1030_1031delTG, p.Trp344fs*2) in an MFDM Chinese patient with craniofacial dysmorphism including ear canal structures and microcephaly, mild intellectual disability, and developmental delay. We generated a zebrafish model of eftud2 deficiency, and a consistent phenotype consisting of mandibular bone dysplasia and otolith loss was observed. We also showed that EFTUD2 deficiency significantly inhibited proliferation, differentiation, and maturation in human calvarial osteoblast (HCO) and human articular chondrocyte (HC-a) cells. RNA-Seq analysis uncovered activated TP53 signaling with increased phosphorylation of the TP53 protein and upregulation of five TP53 downstream target genes (FAS, STEAP3, CASP3, P21, and SESN1) both in HCO and in eftud2−/− zebrafish. Additionally, inhibition of p53 by morpholino significantly reduced the mortality of eftud2−/− larvae.

Conclusions

Our results confirm a novel de novo variant of the EFTUD2 gene and suggest that EFTUD2 may participate in the maturation and differentiation of osteoblasts and chondrocytes, possibly via activation of the TP53 signaling pathway. Thus, mutations in this gene may lead to skeletal anomalies in vertebrates.

Advances in Genomic Profiling and Risk Stratification in Acute Myeloid Leukemia

OBJECTIVE

To review the current state of molecular and genetic profiling of acute myeloid leukemia (AML) and its implications.

DATA SOURCE

Peer-reviewed journal articles.

CONCLUSION

Significant advances in the understanding of the pathology of acute myeloid leukemia have led to refined risk stratification of patients and application of novel targeted therapies based on genetic profiles. Minimal residual disease testing allows for highly sensitive disease surveillance that can be used to predict relapse and assess treatment response.

IMPLICATIONS FOR NURSING PRACTICE

Accurate prognostication and therapeutic decision-making for patients with acute myeloid leukemia is dependent on molecular profiling. Being knowledgeable of the implications of minimal residual disease testing is critical for patient-centered care.

Effect of Chromatographic Conditions on Supercoiled Plasmid DNA Stability and Bioactivity

The dysfunction of the tumor suppressor gene TP53 has been associated with the pathogenesis of the majority of the cases of cancer reported to date, leading the cell to acquire different features known as the cancer hallmarks. In normal situations, the protein p53 protects the cells against tumorigenesis. By detecting metabolic stress or DNA damage in response to stress, p53 can lead the cell to senescence, autophagy, cell cycle arrest, DNA repair, and apoptosis. Thus, in the case of p53 mutations, it is reasonable to assume that the reestablishment of its function, may restrain the proliferation of cancer cells. The concept of cancer gene therapy can be based on this assumption, and suitable biotechnological approaches must be explored to assure the preparation of gene-based biopharmaceuticals. Although numerous procedures have already been established to purify supercoiled plasmid DNA (sc pDNA), the therapeutic application is highly dependent on the biopharmaceutical’s activity, which can be affected by the chromatographic conditions used. Thus, the present work aims at comparing quality and in vitro activity of the supercoiled (sc) isoform of the p53 encoding plasmid purified by three different amino acids-based chromatographic strategies, involving histidine–agarose, arginine–macroporous, and histidine–monolith supports. The B-DNA topology was maintained in all purified pDNA samples, but their bioactivity, related to the induction of protein p53 expression and apoptosis in cancer cells, was higher with arginine–macroporous support, followed by histidine–monolith and histidine–agarose. Despite the purity degree of 92% and recovery yield of 43% obtained with arginine–macroporous, the sc pDNA sample led to a higher expression level of the therapeutic p53 protein (58%) and, consequently, induced a slightly higher apoptotic effect (27%) compared with sc pDNA samples obtained with histidine–monolithic support (26%) and histidine–agarose support (24%). This behavior can be related to the mild chromatographic conditions used with arginine–macroporous support, which includes the use of low salt concentrations, at neutral pH and lower temperatures, when compared to the high ionic strength of ammonium sulfate and acidic pH used with histidine-based supports. These results can contribute to field of biopharmaceutical preparation, emphasizing the need to control several experimental conditions while adapting and selecting the methodologies that enable the use of milder conditions as this can have a significant impact on pDNA stability and biological activity.

Identification of Flap endonuclease 1 as a potential core gene in hepatocellular carcinoma by integrated bioinformatics analysis

Hepatocellular carcinoma (HCC) is a common yet deadly form of malignant cancer. However, the specific mechanisms involved in HCC diagnosis have not yet fully elucidated. Herein, we screened four publically available Gene Expression Omnibus (GEO) expression profiles (GSE14520, GSE29721, GSE45267 and GSE60502), and used them to identify 409 differentially expressed genes (DEGs), including 142 and 267 up- and down-regulated genes, respectively. The DAVID database was used to look for functionally enriched pathways among DEGs, and the STRING database and Cytoscape platform were used to generate a protein-protein interaction (PPI) network for these DEGs. The cytoHubba plug-in was utilized to detect 185 hub genes, and three key clustering modules were constructed with the MCODE plug-in. Gene functional enrichment analyses of these three key clustering modules were further performed, and nine core genes including BIRC5, DLGAP5, DTL, FEN1, KIAA0101, KIF4A, MCM2, MKI67, and RFC4, were identified in the most critical cluster. Subsequently, the hierarchical clustering and expression of core genes in TCGA liver cancer tissues were analyzed using the UCSC Cancer Genomics Browser, and whether elevated core gene expression was linked to a poor prognosis in HCC patients was assessed using the GEPIA database. The PPI of the nine core genes revealed an interaction between FEN1, MCM2, RFC4, and BIRC5. Furthermore, the expression of FEN1 was positively correlated with that of three other core genes in TCGA liver cancer tissues. FEN1 expression in HCC and other tumor types was assessed with the FIREBROWSE and ONCOMINE databases, and results were verified in HCC samples and hepatoma cells. FEN1 levels were also positively correlated with tumor size, distant metastasis and vascular invasion. In conclusion, we identified nine core genes associated with HCC development, offering novel insight into HCC progression. In particular, the aberrantly elevated FEN1 may represent a potential biomarker for HCC diagnosis and treatment.

Mutations in exon 8 of TP53 are associated with shorter survival in patients with advanced lung cancer

Currently, in clinical settings, all TP53 mutations have been considered equally. However, numerous studies have demonstrated that the position and type of mutation have differential effects on prognosis. Such discrepancy can be partially due to the lack of unifying classification system for TP53 mutations. In the present study, two of the most frequently used systems were compared, according to the location of the mutation or its functional effects on p53 protein and the impact of TP53 mutations on the overall survival (OS) time of 379 Chinese patients with advanced lung cancer was analyzed. Capture-based ultra-deep targeted sequencing on plasma samples of 379 patients with advanced lung cancer was performed. The present results suggested that mutations occurring in exon 8 may be associated with shorter OS in tyrosine kinase inhibitor-naïve patients (P=0.013) and in patients previously treated with one line of treatment (P=0.032). The results of the present study provided solid evidence that not all TP53 mutations were associated with a similar prognosis. Mutations in exon 8 were found in a subgroup of patients with unfavorable prognosis across various treatment histories. To the best of our knowledge, the present study is the first to compare different TP53 mutation classification systems in a large cohort of patients with advanced lung cancer.

Difference in pathogenicity of 2 strains of avian leukosis virus subgroup J in broiler chicken

Avian leukosis virus subgroup J has been found to infect many types of chickens with various genetic backgrounds. The ALV-J strain NX0101, which was isolated from broiler breeders in 2001, mainly induces the formation of myeloid cell tumors. However, strain HN10PY01, which was recently isolated from laying hens, mainly induces the formation of myeloid cell tumors and hemangioma. In order to determine the difference in pathogenicity of the 2 strains in broiler chickens, 2 groups of chicken embryos were infected with NA0101 and HN10PY01 separately. A comparison was made of the mortality, oncogenicity, body weights, indexes for immune organs, levels of ALV group-specific antigen p27, and mRNA expression levels of the tumor-related gene, p53, in ALV-J-infected birds and immune organs of theses chickens in response to Newcastle Disease Virus (NDV) and avian influenza virus subtype H9 (AIV-H9) vaccination. The results indicated that strain NX0101 was highly pathogenic in broiler chickens and led to a 30% mortality rate and 45% oncogenicity, compared with the HN10PY01-infected birds. Weight of chickens was also significantly lower after 15 wk (P < 0.05). In addition, the mRNA expression levels of tumor-related p53 in medulla, liver, and lung in broilers infected with strain NX0101 were significantly higher than those infected with strain HN10PY01 (P < 0.05). These results indicated that strain NX0101 had a higher replication ability in broiler chickens. The findings of this study will contribute to further elucidating the mechanisms underlying host susceptibility and tumor classification in ALV-J-infected chickens.

Towards controlled terminology for reporting germline cancer susceptibility variants: an ENIGMA report

The vocabulary currently used to describe genetic variants and their consequences reflects many years of studying and discovering monogenic disease with high penetrance. With the recent rapid expansion of genetic testing brought about by wide availability of high-throughput massively parallel sequencing platforms, accurate variant interpretation has become a major issue. The vocabulary used to describe single genetic variants in silico, in vitro, in vivo and as a contributor to human disease uses terms in common, but the meaning is not necessarily shared across all these contexts. In the setting of cancer genetic tests, the added dimension of using data from genetic sequencing of tumour DNA to direct treatment is an additional source of confusion to those who are not experienced in cancer genetics. The language used to describe variants identified in cancer susceptibility genetic testing typically still reflects an outdated paradigm of Mendelian inheritance with dichotomous outcomes. Cancer is a common disease with complex genetic architecture; an improved lexicon is required to better communicate among scientists, clinicians and patients, the risks and implications of genetic variants detected. This review arises from a recognition of, and discussion about, inconsistencies in vocabulary usage by members of the ENIGMA international multidisciplinary consortium focused on variant classification in breast-ovarian cancer susceptibility genes. It sets out the vocabulary commonly used in genetic variant interpretation and reporting, and suggests a framework for a common vocabulary that may facilitate understanding and clarity in clinical reporting of germline genetic tests for cancer susceptibility.

Identification of critical pathways and hub genes in TP53 mutation prostate cancer by bioinformatics analysis

Aim: The TP53 mutant is one of the most common mutant genes in prostate cancer. Materials & methods: The RNA-seq data of prostate cancer was downloaded from TCGA database. Gene set and enrichment analyses were done by online tools. Results: TP53 mutation was found in 18% prostate cancer patients. Enrichment analysis indicated that differentially expressed genes were enriched in GPCR signaling pathways, cell growth and metabolism. The top ten hub genes were identified. Further analysis showed increased risk of recurrence, lower TP53 mRNA level and higher Gleason scores in patients with TP53 mutation. Conclusion: Our results suggest that multiple genes and pathways may play key roles in TP53 mutant prostate cancer, providing candidate targets and strategies for individualized treatment.

Current status and new treatment approaches in TP53 mutated AML

Mutations in the essential tumor suppressor gene, TP53, are observed in only 5-10% of acute myeloid leukemia (AML) cases, but are highly associated with therapy-related AML and cases with complex karyotype. The mutational status of TP53 is a critical prognostic indicator, with dismal outcomes consistently observed across studies. Response rates to traditional cytotoxic chemotherapy are poor and long-term survival after allogeneic hematopoietic stem cell transplant is rare. Therapy with hypomethylating agents has resulted in a modest improvement in outcomes over intensive chemotherapy, but durable responses are seldom observed. In view of the intrinsic resistance to standard chemotherapies conferred by mutations in TP53, novel treatment approaches are required. In this review, we examine the current treatment landscape in TP53 mutated AML and discuss emerging therapeutic approaches currently under clinical investigation.

Therapeutic targeting of mutant p53 in pediatric acute lymphoblastic leukemia

Alterations of the tumor suppressor gene TP53 are found in different cancers, in particular in carcinomas of adults. In pediatric acute lymphoblastic leukemia (ALL), TP53 mutations are infrequent but enriched at relapse. As in most cancers, mainly DNA-binding domain missense mutations are found, resulting in accumulation of mutant p53, poor therapy response, and inferior outcome. Different strategies to target mutant p53 have been developed including reactivation of p53's wildtype function by the small molecule APR-246. We investigated TP53 mutations in cell lines and 62 B-cell precursor ALL samples and evaluated the activity of APR-246 in TP53-mutated or wildtype ALL. We identified cases with TP53 missense mutations, high (mutant) p53 expression and insensitivity to the DNA-damaging agent doxorubicin. In TP53-mutated ALL, APR-246 induced apoptosis showing strong anti-leukemia activity. APR-246 restored mutant p53 to its wildtype conformation, leading to pathway activation with induction of transcriptional targets and re-sensitization to genotoxic therapy in vitro and in vivo In addition, induction of oxidative stress contributed to APR-246-mediated cell death. In a preclinical model of patient-derived TP53-mutant ALL, APR-246 reduced leukemia burden and synergized strongly with the genotoxic agent doxorubicin, leading to superior leukemia-free survival in vivo Thus, targeting mutant p53 by APR-246, restoring its tumor suppressive function, seems to be an effective therapeutic strategy for this high-risk group of TP53-mutant ALL.

Mutant p53 and Cellular Stress Pathways: A Criminal Alliance That Promotes Cancer Progression

The capability of cancer cells to manage stress induced by hypoxia, nutrient shortage, acidosis, redox imbalance, loss of calcium homeostasis and exposure to drugs is a key factor to ensure cancer survival and chemoresistance. Among the protective mechanisms utilized by cancer cells to cope with stress a pivotal role is played by the activation of heat shock proteins (HSP) response, anti-oxidant response induced by nuclear factor erythroid 2-related factor 2 (NRF2), the hypoxia-inducible factor-1 (HIF-1), the unfolded protein response (UPR) and autophagy, cellular processes strictly interconnected. However, depending on the type, intensity or duration of cellular stress, the balance between pro-survival and pro-death pathways may change, and cell survival may be shifted into cell death. Mutations of p53 (mutp53), occurring in more than 50% of human cancers, may confer oncogenic gain-of-function (GOF) to the protein, mainly due to its stabilization and interaction with the above reported cellular pathways that help cancer cells to adapt to stress. This review will focus on the interplay of mutp53 with HSPs, NRF2, UPR, and autophagy and discuss how the manipulation of these interconnected processes may tip the balance towards cell death or survival, particularly in response to therapies.

Long non-coding RNA ES1 controls the proliferation of breast cancer cells by regulating the Oct4/Sox2/miR-302 axis

ES1 is a long non-coding RNA (lncRNA) that regulates pluripotency of human embryonic stem cells, which is known to be a downstream target of stemness factors Oct4 and Nanog, and serves as a modular scaffold for Sox2. However, the role of ES1 in cancer biology is not fully characterized. The results of our study show that ES1 transcript is upregulated in both high-grade and P53-mutated breast tumor tissues. Knockdown experiments show that ES1 suppression in breast cancer cells restricts cancer cell proliferation and cell cycle progression. Moreover, ES1 inhibition can also induce apoptosis and cellular senescence. Additionally, our data reveal that ES1 transcript promotes cell migration as well as the epithelial to mesenchymal transition of breast cancer cells. Furthermore, loss of ES1 expression downregulates the expression of Oct4/Sox2 and consequently leads to downregulation of their targets, miR-302 and miR-106b. Altogether, for the first time, our findings reveal that ES1 controls the proliferation and death of breast cancer cells by regulating the Oct4/Sox2/miR-302/miR-106b axis.

Concomitant TP53 mutations with response to crizotinib treatment in patients with ALK-rearranged non-small-cell lung cancer

Background

TP53 mutations are the most prevalent mutations detected in non‐small‐cell lung cancer (NSCLC) and have been revealed as a negative prognostic biomarker of outcome. The impact of concomitant TP53 mutations in ALK‐rearranged NSCLC remains uncertain.

Methods

Tumor samples from 64 ALK‐rearranged NSCLC patients receiving crizotinib treatment were subjected to next‐generation sequencing (NGS) to identify TP53 mutational status. The clinicopathologic features of the TP53 mutations and its impact on the effect of crizotinib treatment were analyzed.

Results

Among the 64 ALK‐rearranged patients, 15 (23.4%) patients showed a TP53 mutation. Of these, six cases had disruptive mutations and nine with nondisruptive mutations. The objective response rate (ORR) and disease control rate (DCR) for TP53 mutated patients were both significantly lower compared with those for TP53 wild‐type patients (p = 0.003 and 0.023, respectively). A significantly shorter progression‐free survival (PFS) was found in TP53 mutated patients compared with TP53 wild‐type patients (p = 0.045). Nondisruptive TP53 mutations were associated with a shorter PFS in comparison with disruptive TP53 mutations in ALK‐rearranged patients (p = 0.069). When nondisruptive TP53 mutated patients were in comparison with TP53 wild‐type patients, nondisruptive TP53 mutations were associated with a significant reduced PFS (p = 0.003).

Conclusions

TP53 mutations, especially nondisruptive mutations, negatively affected the response to crizotinib and correlated with shorter PFS in ALK‐rearranged NSCLC patients.

Tyrosine Kinase Inhibitor Imatinib Mesylate Alters DMBA-Induced Early Onco/Suppressor Gene Expression with Tissue-Specificity in Mice

Tyrosine kinases play crucial roles in cellular development and tumorigenesis. Tyrosine kinase inhibitors (TKIs) are effective and widely used drug molecules in targeted cancer therapies. Altered expressions of protooncogenes and tumor suppressor genes after DMBA (7,12-dimethylbenz[a]anthracene) treatment have been described as early markers of tumor induction; however their tissue-specific effects remain still unclear. Our study was aimed at examining the short-term possible antineoplastic and chemopreventive effects of a TKI compound (imatinib mesylate) on a DMBA-induced mouse tumor model. In addition, we also investigated the tissue-specific expressions of Hras, Kras, Myc, and Trp53 genes in the brain, bone marrow, spleen, liver, abdominal lymph nodes, thymus, lungs, and kidneys, respectively. 24 hours after the imatinib mesylate injection, we observed significant Kras downregulation in the bone marrow and lung of the DMBA-treated mice. Moreover, the mRNA expression of Myc was also found to be decreased significantly in the spleen. Interestingly, while Trp53 expression was significantly increased in the lung, it was decreased in the other tissues. However, there was also a tendency in the decreased Myc level in the bone marrow, brain, kidneys, lungs, and lymph nodes and in the decreased Hras level in the bone marrow, kidneys, and lungs, although no significant differences were observed. Our findings indicate rapid tissue-specific impact of imatinib mesylate on DMBA-induced gene expression in vivo, supporting the chemopreventive potential of imatinib mesylate in cancer.

Regulators of Oncogenic Mutant TP53 Gain of Function

The tumor suppressor p53 (TP53) is the most frequently mutated human gene. Mutations in TP53 not only disrupt its tumor suppressor function, but also endow oncogenic gain-of-function (GOF) activities in a manner independent of wild-type TP53 (wtp53). Mutant TP53 (mutp53) GOF is mainly mediated by its binding with other tumor suppressive or oncogenic proteins. Increasing evidence indicates that stabilization of mutp53 is crucial for its GOF activity. However, little is known about factors that alter mutp53 stability and its oncogenic GOF activities. In this review article, we primarily summarize key regulators of mutp53 stability/activities, including genotoxic stress, post-translational modifications, ubiquitin ligases, and molecular chaperones, as well as a single nucleotide polymorphism (SNP) and dimer-forming mutations in mutp53.

Complexes formed by mutant p53 and their roles in breast cancer

Breast cancer is the most frequently diagnosed malignancy in women, and mutations in the tumor suppressor p53 are commonly detected in the most aggressive subtypes. The majority of TP53 gene alterations are missense substitutions, leading to expression of mutant forms of the p53 protein that are frequently detected at high levels in cancer cells. P53 mutants not only lose the physiological tumor-suppressive activity of the wild-type p53 protein but also acquire novel powerful oncogenic functions, referred to as gain of function, that may actively confer a selective advantage during tumor progression. Some of the best-characterized oncogenic activities of mutant p53 are mediated by its ability to form aberrant protein complexes with other transcription factors or proteins not directly related to gene transcription. The set of cellular proteins available to interact with mutant p53 is dependent on cell type and extensively affected by environmental signals, so the prognostic impact of p53 mutation is complex. Specific functional interactions of mutant p53 can profoundly impact homeostasis of breast cancer cells, reprogramming gene expression in response to specific extracellular inputs or cell-intrinsic conditions. The list of protein complexes involving mutant p53 in breast cancer is continuously growing, as is the number of oncogenic phenotypes in which they could be involved. In consideration of the functional impact of such complexes, key interactions of mutant p53 may be exploited as potential targets for development of therapies aimed at defusing the oncogenic potential of p53 mutation.