p53 in breast cancer subtypes and new insights into response to chemotherapy

Clinicopathological importance of Bcl-2 and p53 in postmenopausal triple-negative breast carcinoma and association with age

Appropriate biomarkers are required to predict the clinical outcome of triple-negative breast cancer (TNBC). In this study, we focused on the clinical importance of two representative tumor-associated proteins, Bcl-2 and p53. Bcl-2 expression is usually related to estrogen receptor expression and a favorable outcome in breast cancer. TNBC has been reported to show a high frequency of p53 positivity suggesting TP53 mutations. The expressions of Bcl-2 and p53 were immunohistochemically examined in TNBC involving two age groups of postmenopausal women (≥75 y/o, n = 75; 55-64 y/o, n = 47), who underwent surgery without neoadjuvant therapy. We examined their associations with each other, or with clinicopathological factors including the outcome. Bcl-2 expression was inversely correlated with androgen receptor, apocrine morphology, and p53 expressions, and was an independent predictor of a poor outcome in total or in younger women. p53 positivity was associated with a more favorable outcome than p53 negativity in the younger group. In combined analyzes, none of the twenty Bcl-2-negative/p53-positive cases in the younger group exhibited recurrence, resulting in the independent favorable predictive value of Bcl-2-negative/p53-positive. The anti-apoptotic nature of Bcl-2 may be apparent in TNBC. The excellent outcome of Bcl-2-negative/p53-positive cases in the younger group warrants further combined investigation of Bcl-2/p53 in TNBC.

Aberrant p53 immunostaining patterns in breast carcinoma of no special type strongly correlate with presence and type of TP53 mutations

Recent studies have revealed an association between TP53 mutations and endocrine resistance in hormone receptor-positive, HER2-negative breast cancer (HR + HER2 -BC). Aberrant p53 immunostaining (IHC) patterns may provide a surrogate marker for TP53 mutations. Building upon a ternary algorithm of aberrant staining patterns, this study evaluates the reliability of p53 IHC as screening tool for TP53 mutations in BC (NST). Furthermore, it describes the histopathological and molecular characteristics of TP53-mutated cases, along with the mutational status of PIK3CA. This study comprised 131 early-stage, node-negative BCs with available core biopsies and resection specimens. Cases were categorized as follows: HR + HER2 - (85 cases), HER2 + (21 cases) and triple negative (TN, 25 cases). Aberrant IHC staining patterns for p53 were defined as overexpression (OE), complete absence (CA) and cytoplasmic (CY). In addition, targeted sequencing of TP53 and PIK3CA genes was performed. TP53 mutations were identified in 53 of 126 cases (42.1%). Within HR + HER2 - cases, TP53 mutations were found in 17 of 80 cases (21.3%). IHC accurately predicted TP53 mutation in 96.2% of cases with a specificity of 100%. Additionally, there was a significant agreement between missense mutations and OE, as well as between truncating mutations and CA (κ 73% and 76%). CY was observed in two TN cases with truncating mutations within the nuclear localization signalling domain of p53. TP53-mutated cases exhibited higher grade, greater nuclear pleomorphism and higher Ki-67 proliferation index and were associated with the PIK3CA wild-type status (p < 0.001). p53 IHC may provide a useful screening tool for identifying TP53-mutated BC of NST.

p53R172H and p53R245W Hotspot Mutations Drive Distinct Transcriptomes in Mouse Mammary Tumors Through a Convergent Transcriptional Mediator

Aggressive breast cancers harbor TP53 missense mutations. Tumor cells with TP53 missense mutations exhibit enhanced growth and survival through transcriptional rewiring. To delineate how TP53 mutations in breast cancer contribute to tumorigenesis and progression in vivo, we created a somatic mouse model driven by mammary epithelial cell-specific expression of Trp53 mutations. Mice developed primary mammary tumors reflecting the human molecular subtypes of luminal A, luminal B, HER2-enriched, and triple-negative breast cancer with metastases. Transcriptomic analyses comparing MaPR172H/- or MaPR245W/- mammary tumors to MaP-/- tumors revealed (1) differences in cancer-associated pathways activated in both p53 mutants and (2) Nr5a2 as a novel transcriptional mediator of distinct pathways in p53 mutants. Meta-analyses of human breast tumors corroborated these results. In vitro assays demonstrate mutant p53 upregulates specific target genes that are enriched for Nr5a2 response elements in their promoters. Co-immunoprecipitation studies revealed p53R172H and p53R245W interact with Nr5a2. These findings implicate NR5A2 as a novel mediator of mutant p53 transcriptional activity in breast cancer.

SIGNIFICANCE

Our findings implicate NR5A2 as a novel mediator of mutant p53 transcriptional activity in breast cancer. NR5A2 may be an important therapeutic target in hard-to-treat breast cancers such as endocrine-resistant tumors and metastatic triple-negative breast cancers harboring TP53 missense mutations.

Molecular and Pathobiology of Canine Mammary Tumour: Defining a Translational Model for Human Breast Cancer

Canine mammary tumours (CMT) have histological, clinicopathological and molecular resemblances to human breast cancer (HBC), positioning them as viable models for studying the human disease. CMT initiation and progression occur spontaneously in immune-competent animals, which challenge the suggested limitations of genetically modified mice, also enabling the evaluation of immunotherapies in canine patients. Dogs have shorter life expectancy compared to humans, and cancer advances more rapidly in this species. This makes it possible to perform studies about the clinical efficacy of new therapeutic modalities in a much shorter time than in human patients. The identification of biomarkers for tumour subtypes, progression and treatment response paves the way for the development of novel therapeutic and diagnostic approaches. This review addresses the similarities between CMT and HBC and the molecular signatures identified in CMT samples that have been explored to date. We proposed a detailed molecular exploration of the CMT stroma using state-of-the-art methods in transcriptomics and proteomics. Using CMT as an analog for HBC not only helps to understand the complexities of the disease, but also to advance comparative oncology to the next level to prove the claim of dogs as a valid translational model.

Mitotic catastrophe heterogeneity: implications for prognosis and immunotherapy in hepatocellular carcinoma

Background and aims

The mitotic catastrophe (MC) pathway plays an important role in hepatocellular carcinoma (HCC) progression and tumor microenvironment (TME) regulation. However, the mechanisms linking MC heterogeneity to immune evasion and treatment response remain unclear.

Methods

Based on 94 previously published highly correlated genes for MC, HCC patients' data from the Cancer Genome Atlas (TCGA) and changes in immune signatures and prognostic stratification were studied. Time and spatial-specific differences for MCGs were assessed by single-cell RNA sequencing and spatial transcriptome (ST) analysis. Multiple external databases (GEO, ICGC) were employed to construct an MC-related riskscore model.

Results

Identification of two MC-related subtypes in HCC patients from TCGA, with clear differences in immune signatures and prognostic risk stratification. Spatial mapping further associates low MC tumor regions with significant immune escape-related signaling. Nomogram combining MC riskscore and traditional indicators was validated great effect for early prediction of HCC patient outcomes.

Conclusion

MC heterogeneity enables immune escape and therapy resistance in HCC. The MC gene signature serves as a reliable prognostic indicator for liver cancer. By revealing clear immune and spatial heterogeneity of HCC, our integrated approach provides contextual therapeutic strategies for optimal clinical decision-making.

Dynamic changes in tumor profiling reveal intra- and inter-tumoral heterogeneity focused on an uncharacterized HER2 mutation: a case report of a young breast cancer patient

Despite multiple recent advances in systemic therapy for metastatic breast cancer, cases which display suboptimal response to guideline-driven treatment are frequently seen in the clinic. Effective options for such patients are limited, particularly in later line of therapy, and selection of optimal treatment options is essentially empirical and based largely on considerations of previous regimens received. Comprehensive cancer profiling includes detection of genetic alterations in tissue and circulating tumor DNA (ctDNA), immunohistochemistry (IHC) from re-biopsied metastatic disease, circulating tumor cells (CTCs), gene expression analysis and pharmacogenomics. The advent of this methodology and application to metastatic breast cancer, facilitates a more scientifically informed approach to identification of optimal systemic therapy approaches independent of the restrictions implied by clinical guidelines. Here we describe a case of metastatic breast cancer where consecutive comprehensive tumor profiling reveals ongoing tumor evolution, guiding the identification of novel effective therapeutic strategies.

Nanoreceptors promote mutant p53 protein degradation by mimicking selective autophagy receptors

In some cancers mutant p53 promotes the occurrence, development, metastasis and drug resistance of tumours, with targeted protein degradation seen as an effective therapeutic strategy. However, a lack of specific autophagy receptors limits this. Here, we propose the synthesis of biomimetic nanoreceptors (NRs) that mimic selective autophagy receptors. The NRs have both a component for targeting the desired protein, mutant-p53-binding peptide, and a component for enhancing degradation, cationic lipid. The peptide can bind to mutant p53 while the cationic lipid simultaneously targets autophagosomes and elevates the levels of autophagosome formation, increasing mutant p53 degradation. The NRs are demonstrated in vitro and in a patient-derived xenograft ovarian cancer model in vivo. The work highlights a possible direction for treating diseases by protein degradation.

MicroRNA-190b Targets RFWD3 in Estrogen Receptor-Positive Breast Cancer

Background

In the year 2020, breast cancer was the most common form of cancer worldwide. Roughly 70% of breast cancers are estrogen receptor-positive (ER+). MicroRNA-190b (miR-190b) has previously been reported to be upregulated in ER+ breast cancers. Previously, we have demonstrated that miR-190b is hypomethylated in ER+ breast cancers, potentially leading to its upregulation.

Objectives

To further study the role of miR-190b in ER+ breast cancer and to identify its clinically relevant targets in breast cancer.

Design

Patient cohort and cell line-based RNA-sequencing analysis.

Methods

The Cancer Genome Atlas was used to obtain gene expression data and clinical information on patients with breast cancer. To identify messenger RNA (mRNA) targets for miR-190b, the ER+ breast cancer cell line T-47D was used to immunoprecipitate biotin-labeled miR-190b followed by RNA sequencing. Western blot was used to confirm miR-190b target. Patient survival based on miR-190b and selected target was studied using the Cancer Genome Atlas.

Results

In this study, we confirm that miR-190b is overexpressed in breast cancer via differential expression analysis and show that high expression of miR-190b results in more favorable outcomes in Luminal A patients, hazard ratio (HR) = 0.29, 95% confidence interval [CI] = 0.12-0.71, P = .0063. MicroRNA-190b target analysis identified RING finger and WD repeat domain 3 (RFWD3) as one of miR-190b regulatory targets in ER+ breast cancer. Survival analysis of RFWD3 showed that elevated levels result in poorer overall survival in patients with Luminal A breast cancer (HR = 2.22, 95% CI = 1.33-3.71, P = .002). Gene ontology analysis of our sequencing results indicates that miR-190b may have a role in breast cancer development and/or tumorigenesis and that it may be a suitable tool in characterization between the ER+ subtypes, Luminal A, and Luminal B.

Conclusions

We show that miR-190b targets RFWD3 in ER+ breast cancers leading to lower RFWD3 protein expression. Low levels of RFWD3 are associated with better outcomes in patients with Luminal A breast cancer but not in patients with Luminal B breast cancer. These findings provide novel insights into miR-190b role in breast cancer and that its clinical relevance is subtype specific.

Altered hormone expression induced genetic changes leads to breast cancer

PURPOSE OF REVIEW

Breast cancer ranks first among gynecological cancer in India. It is associated with urbanization, changes in lifestyle and obesity. Hormones also play a crucial role in the development of breast cancer. Steroid hormones play critical role in development of breast cancer.

RECENT FINDING

Breast cancer is caused due to alteration in different hormone expressions leading to genetic instability. Loss or gains of functions due to genetic instability were associated with the alterations in housekeeping genes. Up-regulation in c-myc, signal transducer and activator of transcription (STAT), CREB-regulated transcription coactivator (CRTC), and eukaryotic translation initiation factor 4E (eIF4E) may cause the development of breast cancer. Peptide hormones are commonly following the phosphoinositide 3-kinases (PI3K) pathway for activation of cell cycle causing uncontrolled proliferation. Although steroid hormones are following the Ras/Raf/mitogen-activated protein kinase (MEK) pathway, their hyper-activation of these pathways causes extracellular-signal-regulated kinase (ERK) and MAPK activation, leading to carcinogenesis.

SUMMARY

Alteration in cell cycle proteins, oncogenes, tumor suppressor genes, transcription and translation factors lead to breast cancer. Apoptosis plays a vital role in the elimination of abnormal cells but failure in any of these apoptotic pathways may cause tumorigenesis. Hence, a complex interplay of hormonal and genetic factors is required to maintain homeostasis in breast cells. Imbalance in homeostasis of these hormone and genes may lead to breast cancer.

Construction of an oxidative stress-associated genes signature in breast cancer by machine learning algorithms

OBJECTIVE

To construct a prognostic model of a breast cancer-related oxidative stress-related gene (OSRG) signature using machine learning algorithms.

METHODS

The OSRGs of breast cancer were constructed by least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression analysis. The Cancer Genome Atlas (TCGA) was used to analyse the gene expression and prognostic value. The Human Protein Atlas was used to analyse the protein expression of hub genes. Receiver operating characteristic analysis, calibration curve and decision curve analysis were used to predict the stability of this model.

RESULTS

The area under the curve of 1-, 3- and 5-year overall survival were 0.751, 0.707 and 0.645 in the TCGA training dataset; and 0.692, 0.678 and 0.602 in the TCGA testing dataset, respectively. Calibration plot showed good agreement between predicted probabilities and observed outcomes. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Set Enrichment Analysis (GSEA) pathway analysis indicated that multiple cancer-related pathways were highly enriched in the high-risk group. Immune infiltration analysis showed immune cells and their functions may play a key role in the development and mechanism of breast cancer.

CONCLUSIONS

This new OSRG signature was associated with the immune infiltration and it might be useful in predicting the prognosis in patients with breast cancer.

Canine Mammary Cancer: State of the Art and Future Perspectives

Mammary cancer is the most frequently diagnosed neoplasia in women and non-spayed female dogs and is one of the leading causes of death in both species. Canines develop spontaneous mammary tumors that share a significant number of biological, clinical, pathological and molecular characteristics with human breast cancers. This review provides a detailed description of the histological, molecular and clinical aspects of mammary cancer in canines; it discusses risk factors and currently available diagnostic and treatment options, as well as remaining challenges and unanswered questions. The incidence of mammary tumors is highly variable and is impacted by biological, pathological, cultural and socioeconomic factors, including hormonal status, breed, advanced age, obesity and diet. Diagnosis is mainly based on histopathology, although several efforts have been made to establish a molecular classification of canine mammary tumors to widen the spectrum of treatment options, which today rely heavily on surgical removal of tumors. Lastly, standardization of clinical study protocols, development of canine-specific biological tools, establishment of adequate dog-specific disease biomarkers and identification of targets for the development of new therapies that could improve survival and have less adverse effects than chemotherapy are among the remaining challenges.

Multidimensional quantitative phenotypic and molecular analysis reveals neomorphic behaviors of p53 missense mutants

Mutations in the TP53 tumor suppressor gene occur in >80% of the triple-negative or basal-like breast cancer. To test whether neomorphic functions of specific TP53 missense mutations contribute to phenotypic heterogeneity, we characterized phenotypes of non-transformed MCF10A-derived cell lines expressing the ten most common missense mutant p53 proteins and observed a wide spectrum of phenotypic changes in cell survival, resistance to apoptosis and anoikis, cell migration, invasion and 3D mammosphere architecture. The p53 mutants R248W, R273C, R248Q, and Y220C are the most aggressive while G245S and Y234C are the least, which correlates with survival rates of basal-like breast cancer patients. Interestingly, a crucial amino acid difference at one position-R273C vs. R273H-has drastic changes on cellular phenotype. RNA-Seq and ChIP-Seq analyses show distinct DNA binding properties of different p53 mutants, yielding heterogeneous transcriptomics profiles, and MD simulation provided structural basis of differential DNA binding of different p53 mutants. Integrative statistical and machine-learning-based pathway analysis on gene expression profiles with phenotype vectors across the mutant cell lines identifies quantitative association of multiple pathways including the Hippo/YAP/TAZ pathway with phenotypic aggressiveness. Further, comparative analyses of large transcriptomics datasets on breast cancer cell lines and tumors suggest that dysregulation of the Hippo/YAP/TAZ pathway plays a key role in driving the cellular phenotypes towards basal-like in the presence of more aggressive p53 mutants. Overall, our study describes distinct gain-of-function impacts on protein functions, transcriptional profiles, and cellular behaviors of different p53 missense mutants, which contribute to clinical phenotypic heterogeneity of triple-negative breast tumors.

Cancer-specific association between Tau (MAPT) and cellular pathways, clinical outcome, and drug response

Tau (MAPT) is a microtubule-associated protein causing common neurodegenerative diseases or rare inherited frontotemporal lobar degenerations. Emerging evidence for non-canonical functions of Tau in DNA repair and P53 regulation suggests its involvement in cancer. To bring new evidence for a relevant role of Tau in cancer, we carried out an in-silico pan-cancer analysis of MAPT transcriptomic profile in over 10000 clinical samples from 32 cancer types and over 1300 pre-clinical samples from 28 cancer types provided by the TCGA and the DEPMAP datasets respectively. MAPT expression associated with key cancer hallmarks including inflammation, proliferation, and epithelial to mesenchymal transition, showing cancer-specific patterns. In some cancer types, MAPT functional networks were affected by P53 mutational status. We identified new associations of MAPT with clinical outcomes and drug response in a context-specific manner. Overall, our findings indicate that the MAPT gene is a potential major player in multiple types of cancer. Importantly, the impact of Tau on cancer seems to be heavily influenced by the specific cellular environment.

Establishing the Link between X-Chromosome Aberrations and TP53 Status, with Breast Cancer Patient Outcomes

Ubiquitous to normal female human somatic cells, X-chromosome inactivation (XCI) tightly regulates the transcriptional silencing of a single X chromosome from each pair. Some genes escape XCI, including crucial tumour suppressors. Cancer susceptibility can be influenced by the variability in the genes that escape XCI. The mechanisms of XCI dysregulation remain poorly understood in complex diseases, including cancer. Using publicly available breast cancer next-generation sequencing data, we show that the status of the major tumour suppressor TP53 from Chromosome 17 is highly associated with the genomic integrity of the inactive X (Xi) and the active X (Xa) chromosomes. Our quantification of XCI and XCI escape demonstrates that aberrant XCI is linked to poor survival. We derived prognostic gene expression signatures associated with either large deletions of Xi; large amplifications of Xa; or abnormal X-methylation. Our findings expose a novel insight into female cancer risks, beyond those associated with the standard molecular subtypes.

Concomitant PIK3CA and TP53 Mutations in Breast Cancer: An Analysis of Clinicopathologic and Mutational Features, Neoadjuvant Therapeutic Response, and Prognosis

PURPOSE

PIK3CA and TP53 are the most prevalently mutated genes in breast cancer (BC). Previous studies have indicated an association between concomitant PIK3CA/TP53 mutations and shorter disease-free survival. As its clinical utility remains largely unknown, we aimed to analyze the prognostic and predictive roles of this co-mutation.

METHODS

We retrospectively analyzed patients who were diagnosed with BC at Guangdong Provincial People's Hospital (GDPH) who underwent next-generation sequencing. The correlation of concomitant PIK3CA/TP53 mutations with clinicopathological and mutational characteristics, and neoadjuvant systemic therapy (NST) responses was analyzed. The Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) dataset was used to verify associations between concurrent mutations and survival outcomes.

RESULTS

In the GDPH cohort, concomitant PIK3CA/TP53 mutations were associated with more aggressive phenotypes, including human epidermal growth factor receptor 2 positive status, hormone receptor negative status, high Ki-67 expression, high histological grade, advanced TNM stage, and additional genetic alterations. Co-mutations also portended a worse response to NST, especially taxane-containing regimens, when compared with the TP53 mutant alone (odds ratio, 3.767; 95% confidence interval, 1.205-13.087; p = 0.028). A significant association was observed between concomitant PIK3CA/TP53 mutations and poor survival outcomes in the METABRIC cohort.

CONCLUSION

Concomitant PIK3CA/TP53 mutations not only suggested unfavorable features and poor prognosis in BC but also conferred less benefit to NST than TP53 mutations alone.

Tumor metabolism rewiring in epithelial ovarian cancer

The mortality rate of epithelial ovarian cancer (EOC) remains the first in malignant tumors of the female reproductive system. The characteristics of rapid proliferation, extensive implanted metastasis, and treatment resistance of cancer cells require an extensive metabolism rewiring during the progression of cancer development. EOC cells satisfy their rapid proliferation through the rewiring of perception, uptake, utilization, and regulation of glucose, lipids, and amino acids. Further, complete implanted metastasis by acquiring a superior advantage in microenvironment nutrients competing. Lastly, success evolves under the treatment stress of chemotherapy and targets therapy. Understanding the above metabolic characteristics of EOCs helps to find new methods of its treatment.

Treatment and Response Evaluation Challenges in a Pregnant Woman With B-Cell Lymphoblastic Leukemia and Li-Fraumeni Syndrome

Li-Fraumeni syndrome (LFS) is a cancer predisposing syndrome caused by pathogenic germline TP53 gene mutations with important therapeutic and prognostic implications for many types of cancer. A small proportion of LFS patients develop B-cell lymphoblastic leukemia (B-ALL) in adult years. Standard treatment often proves inadequate, but immunotherapy has provided new treatment options. The current case report presents a pregnant woman with LFS and newly diagnosed B-ALL with hypodiploidy developed after treatment for early-onset breast cancer. We describe the treatment course, treatment-related complications and provide laboratory data crucial for evaluating and modifying treatment for this difficult clinical case. Our findings support the need for close collaboration between clinicians and experts on immunophenotyping. Through our report, we show that immunotherapy is feasible in patients with LFS and B-ALL, despite a poor initial response to induction therapy.

Pathologic Response to Neoadjuvant Sequential Chemoradiation Therapy in Locally Advanced Breast Cancer: Preliminary, Translational Results from the French Neo-APBI-01 Trial

Background: Radiation therapy (RT), a novel approach to boost the anticancer immune response, has been progressively evaluated in the neoadjuvant setting in breast cancer (BC). Purpose: We aimed to evaluate immunity-related indicators of response to neoadjuvant chemoradiation therapy (NACRT) in BC for better treatment personalization. Patients and Methods: We analyzed data of the first 42 patients included in the randomized phase 2 Neo-APBI-01 trial comparing standard neoadjuvant chemotherapy (NACT) and NACRT regimen in locally advanced triple-negative (TN) and luminal B (LB) subtype BC. Clinicopathological parameters, blood counts and the derived parameters, total tumor-infiltrating lymphocytes (TILs) and their subpopulation, as well as TP53 mutation status, were assessed as predictors of response. Results: Twenty-one patients were equally assigned to each group. The pathologic complete response (pCR) was 33% and 38% in the NACT and NACRT groups, respectively, with a dose-response effect. Only one LB tumor reached pCR after NACRT. Numerous parameters associated with response were identified, which differed according to the assigned treatment. In the NACRT group, baseline hemoglobin of ≥13 g/dL and body mass index of <26 were strongly associated with pCR. Higher baseline neutrophils-to-lymphocytes ratio, total TILs, and T-effector cell counts were favorable for pCR. Conclusion: This preliminary analysis identified LB and low-TIL tumors as poor responders to the NACRT protocol, which delivered RT after several cycles of chemotherapy. These findings will allow for amending the selection of patients for the trial and help better design future trials of NACRT in BC.

Molecular Profile and Matched Targeted Therapy for Advanced Breast Cancer Patients

(1) Background: Precision oncology is opening new treatment opportunities for patients suffering from solid tumors. In the last two decades, the advent of CDK4/6 inhibitors, immunotherapy, and antibody-drug conjugates (ADC) improved survival outcomes for advanced or metastatic breast cancers (BC). Nevertheless, some patients progress to approved therapies and still maintain good clinical conditions. (2) Methods: With the aim to estimate the accrual rate to experimental precision oncology treatments, we collected molecular and clinical characteristics of BC patients evaluated at Phase 1 Unit of Fondazione Policlinico Gemelli. Clinical data were retrieved from hospital records. Molecular analysis was performed using Next-Generation Sequencing (NGS) FoundationOne CDx on tissue or blood. (3) Results: Among the 38 BC patients referred to our unit, 35 completed the genomic analysis. All patients were female with advanced (mean number of metastatic sites: 3, range 1-6) BC. Median age at our evaluation was 52 (IQR, 48-59). ECOG PS was good in 97% of the study population, although heavily pre-treated (median number of systemic treatments: 5, IQR 3-7). Half of referred patients were HR+/HER2- BC, with 39% triple negative breast cancer (TNBC). NGS testing was performed on relapsed disease among most (71%) participants, in particular lymph nodes and soft tissue. Liquid biopsy was requested in 23% of cases. The median time from sample collection to NGS testing was 1 month and from diagnosis 54 months. The median value of mutations, VUS, and TMB were 6, 11, and 5, respectively. TP53, PIK3CA, BRCA2, ESR1, and RAD21 were the genes with the highest number of molecular alterations. In 5 patients (14%), the molecular analysis was helpful to assign targeted therapy in the context of clinical trials with a median progression-free survival of 5 months. (4) Conclusions: HR+/HER2- and TNBC were the most frequent subtypes referred for NGS testing. Tissue biopsy of relapsed disease was feasible in 71% of cases. The molecular analysis offered a new treatment opportunity in 14% of patients. The real benefit of these treatments remains to be evaluated in larger cohorts.

P53 expression correlates with low axillary tumor burden in breast cancer

BACKGROUND

The p53 mutation in breast cancer confers a worse prognosis and is usually associated with p53 overexpression (p53+) on immunohistochemistry. Previous studies have shown that p53+ tumors could be associated with low axillary tumor burden (ATB).

OBJECTIVE

We aimed to evaluate the association between p53+ and ATB in a large series of breast cancers as an aid to personalizing axillary surgical treatment.

METHODS

We retrieved 1762 infiltrating breast carcinomas from our database that were treated with upfront surgery in Hospital del Mar from 2004 to 2018. We compared p53+ and p53-negative (p53-) tumors in terms of the percentage of cases with high ATB and overall survival. This comparison was made overall and for each immunophenotype.

RESULTS

Overall, 18.7% of breast tumors were p53+. High ATB was less common in p53+ tumors than in p53- tumors in the luminal B-Her2-negative immunophenotype (6.2% versus 16.9%, respectively, P = 0.025), but not in the other immunophenotypes or overall. Overall survival was worse in patients with p53+ breast cancer (P = 0.002).

CONCLUSION

p53+ breast cancers were associated with worse overall survival. However, low ATB was more common in these tumors than in p53- tumors in the luminal B-Her2-negative subtype. Information on p53 expression could be of use to predict ATB in some breast cancer tumors.

Tumor cell-derived extracellular vesicles for breast cancer specific delivery of therapeutic P53

Breast cancer has consistently had the highest incidence among women in the world. Tumor cell-derived extracellular vesicles (EV) have been leveraged as drug carriers for cancer treatment. Herein, we developed an efficient theranostic platform for breast cancer-specific delivery of lipophilic triphenylphosphonium (TPP)-modified therapeutic recombinant P53 proteins (TPP/P53) by breast cancer cell-derived EVs. We observed that the EVs were routinely captured by their patent cells, so when, TPP/P53 was loaded into the EVs (TPP/P53@EVs), TPP/P53 was targeted to the mitochondria of breast cancer cells, where it caused signal amplification and induced the death of breast cancer cells. Our findings demonstrated that the TPP/P53@EVs showed good tumor-targeting capability and efficiently destroyed the tumor tissues without any obvious toxicity in vivo. Therefore, our TPP/P53@EVs might provide a "drug-free" strategy for future applications in breast cancer therapy.

Hippo-TAZ signaling is the master regulator of the onset of triple-negative basal-like breast cancers

Breast cancer is the most frequent malignancy in women worldwide. Basal-like breast cancer (BLBC) is the most aggressive form of this disease, and patients have a poor prognosis. Here, we present data suggesting that the Hippo-transcriptional coactivator with PDZ-binding motif (TAZ) pathway is a key driver of BLBC onset and progression. Deletion of Mob1a/b in mouse mammary luminal epithelium induced rapid and highly reproducible mammary tumorigenesis that was dependent on TAZ but not yes-associated protein 1 (YAP1). In situ early-stage BLBC-like malignancies developed in mutant animals by 2 wk of age, and invasive BLBC appeared by 4 wk. In a human estrogen receptor⁺ luminal breast cancer cell line, TAZ hyperactivation skewed the features of these luminal cells to the basal phenotype, consistent with the aberrant TAZ activation frequently observed in human precancerous BLBC lesions. TP53 mutation is rare in human precancerous BLBC but frequent in invasive BLBC. Addition of Trp53 deficiency to our Mob1a/b-deficient mouse model enhanced tumor grade and accelerated cancer progression. Our work justifies targeting the Hippo-TAZ pathway as a therapy for human BLBC, and our mouse model represents a powerful tool for evaluating candidate agents.

The activation of M2 muscarinic receptor inhibits cell growth and survival in human epithelial ovarian carcinoma

Ovarian cancer is the fifth leading cause of cancer-related deaths in females. Many ovarian tumor cell lines express muscarinic receptors (mAChRs), and their expression is correlated with reduced survival of patients. We have characterized the expression of mAChRs in two human ovarian carcinoma cell lines (SKOV-3, TOV-21G) and two immortalized ovarian surface epithelium cell lines (iOSE-120, iOSE-398). Among the five subtypes of mAChRs (M1-M5 receptors), we focused our attention on the M2 receptor, which is involved in the inhibition of tumor cell proliferation. Western blot analysis and real-time PCR analyses indicated that the levels of M2 are statistically downregulated in cancer cells. Therefore, we investigated the effect of arecaidine propargyl ester hydrobromide (APE), a preferential M2 agonist, on cell growth and survival. APE treatment decreased cell number in a dose and time-dependent manner by decreasing cell proliferation and increasing cell death. FACS and immunocytochemistry analysis have also demonstrated the ability of APE to accumulate the cells in G2/M phase of the cell cycle and to increase the percentage of abnormal mitosis. The higher level of M2 receptors in the iOSE cells rendered these cells more sensitive to APE treatment than cancer cells. The data here reported suggest that M2 has a negative role in cell growth/survival of ovarian cell lines, and its downregulation may favor tumor progression.

Prognostic Value of Salivary Biochemical Indicators in Primary Resectable Breast Cancer

Despite the fact that breast cancer was detected in the early stages, the prognosis was not always favorable. In this paper, we examined the impact of clinical and pathological characteristics of patients and the composition of saliva before treatment on overall survival and the risk of recurrence of primary resectable breast cancer. The study included 355 patients of the Omsk Clinical Oncology Center with a diagnosis of primary resectable breast cancer (T1-3N0-1M0). Saliva was analyzed for 42 biochemical indicators before the start of treatment. We have identified two biochemical indicators of saliva that can act as prognostic markers: alkaline phosphatase (ALP) and diene conjugates (DC). Favorable prognostic factors were ALP activity above 71.7 U/L and DC level above 3.93 c.u. Additional accounting for aspartate aminotransferase (AST) activity allows for forming a group with a favorable prognosis, for which the relative risk is reduced by more than 11 times (HR = 11.49, 95% CI 1.43-88.99, p = 0.01591). Salivary AST activity has no independent prognostic value. Multivariate analysis showed that tumor size, lymph nodes metastasis status, malignancy grade, tumor HER2 status, and salivary ALP activity were independent predictors. It was shown that the risk of recurrence decreased with menopause and increased with an increase in the size of the primary tumor and lymph node involvement. Significant risk factors for recurrence were salivary ALP activity below 71.7 U/L and DC levels below 3.93 c.u. before treatment. Thus, the assessment of biochemical indicators of saliva before treatment can provide prognostic information comparable in importance to the clinicopathological characteristics of the tumor and can be used to identify a risk group for recurrence in primary resectable breast cancer.

Prognostic significance of RNA-based TP53 pathway function among estrogen receptor positive and negative breast cancer cases

TP53 and estrogen receptor (ER) are essential in breast cancer development and progression, but TP53 status (by DNA sequencing or protein expression) has been inconsistently associated with survival. We evaluated whether RNA-based TP53 classifiers are related to survival. Participants included 3213 women in the Carolina Breast Cancer Study (CBCS) with invasive breast cancer (stages I-III). Tumors were classified for TP53 status (mutant-like/wildtype-like) using an RNA signature. We used Cox proportional hazards models to estimate covariate-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for breast cancer-specific survival (BCSS) among ER- and TP53-defined subtypes. RNA-based results were compared to DNA- and IHC-based TP53 classification, as well as Basal-like versus non-Basal-like subtype. Findings from the diverse (50% Black), population-based CBCS were compared to those from the largely white METABRIC study. RNA-based TP53 mutant-like was associated with BCSS among both ER-negatives and ER-positives (HR (95% CI) = 5.38 (1.84-15.78) and 4.66 (1.79-12.15), respectively). Associations were attenuated when using DNA- or IHC-based TP53 classification. In METABRIC, few ER-negative tumors were TP53-wildtype-like, but TP53 status was a strong predictor of BCSS among ER-positives. In both populations, the effect of TP53 mutant-like status was similar to that for Basal-like subtype. RNA-based measures of TP53 status are strongly associated with BCSS and may have value among ER-negative cancers where few prognostic markers have been robustly validated. Given the role of TP53 in chemotherapeutic response, RNA-based TP53 as a prognostic biomarker could address an unmet need in breast cancer.

Differential Gain-of-Function Activity of Three p53 Hotspot Mutants In Vivo

The majority of TP53 missense mutations identified in cancer patients are in the DNA-binding domain and are characterized as either structural or contact mutations. These missense mutations exhibit inhibitory effects on wild-type p53 activity. More importantly, these mutations also demonstrate gain-of-function (GOF) activities characterized by increased metastasis, poor prognosis, and drug resistance. To better understand the activities by which TP53 mutations, identified in Li-Fraumeni syndrome, contribute to tumorigenesis, we generated mice harboring a novel germline Trp53R245W allele (contact mutation) and compared them with existing models with Trp53R172H (structural mutation) and Trp53R270H (contact mutation) alleles. Thymocytes from heterozygous mice showed that all three hotspot mutations exhibited similar inhibitory effects on wild-type p53 transcription in vivo, and tumors from these mice had similar levels of loss of heterozygosity. However, the overall survival of Trp53R245W/+ and Trp53R270H/+ mice, but not Trp53R172H/+ mice, was significantly shorter than that of Trp53+/- mice, providing strong evidence for p53-mutant-specific GOF contributions to tumor development. Furthermore, Trp53R245W/+ and Trp53R270H/+ mice had more osteosarcoma metastases than Trp53R172H/+ mice, suggesting that these two contact mutants have stronger GOF in driving osteosarcoma metastasis. Transcriptomic analyses using RNA sequencing data from Trp53R172H/+, Trp53R245W/+, and Trp53R270H/+ primary osteosarcomas in comparison with Trp53+/- indicated that GOF of the three mutants was mediated by distinct pathways. Thus, both the inhibitory effect of mutant over wild-type p53 and GOF activities of mutant p53 contributed to tumorigenesis in vivo. Targeting p53 mutant-specific pathways may be important for therapeutic outcomes in osteosarcoma.

SIGNIFICANCE

p53 hotspot mutants inhibit wild-type p53 similarly but differ in their GOF activities, with stronger tumor-promoting activity in contact mutants and distinct protein partners of each mutant driving tumorigenesis and metastasis.

Mutual exclusivity of ESR1 and TP53 mutations in endocrine resistant metastatic breast cancer

Both TP53 and ESR1 mutations occur frequently in estrogen receptor positive (ER+) metastatic breast cancers (MBC) and their distinct roles in breast cancer tumorigenesis and progression are well appreciated. Recent clinical studies discovered mutual exclusivity between TP53 and ESR1 mutations in metastatic breast cancers; however, mechanisms underlying this intriguing clinical observation remain largely understudied and unknown. Here, we explored the interplay between TP53 and ESR1 mutations using publicly available clinical and experimental data sets. We first confirmed the robust mutational exclusivity using six independent cohorts with 1,056 ER+ MBC samples and found that the exclusivity broadly applies to all ER+ breast tumors regardless of their clinical and distinct mutational features. ESR1 mutant tumors do not exhibit differential p53 pathway activity, whereas we identified attenuated ER activity and expression in TP53 mutant tumors, driven by a p53-associated E2 response gene signature. Further, 81% of these p53-associated E2 response genes are either direct targets of wild-type (WT) p53-regulated transactivation or are mutant p53-associated microRNAs, representing bimodal mechanisms of ER suppression. Lastly, we analyzed the very rare cases with co-occurrences of TP53 and ESR1 mutations and found that their simultaneous presence was also associated with reduced ER activity. In addition, tumors with dual mutations showed higher levels of total and PD-L1 positive macrophages. In summary, our study utilized multiple publicly available sources to explore the mechanism underlying the mutual exclusivity between ESR1 and TP53 mutations, providing further insights and testable hypotheses of the molecular interplay between these two pivotal genes in ER+ MBC.

Phase 1b study of berzosertib and cisplatin in patients with advanced triple-negative breast cancer

Platinum derivatives are commonly used for the treatment of patients with metastatic triple-negative breast cancer (TNBC). However, resistance often develops, leading to treatment failure. This expansion cohort (part C2) of the previously reported phase 1b trial (NCT02157792) is based on the recommended phase 2 dose of the combination of the ataxia-telangiectasia and Rad3-related (ATR) inhibitor berzosertib and cisplatin observed in patients with advanced solid tumors, including TNBC. Forty-seven patients aged ≥18 years with advanced TNBC received cisplatin (75 mg/m2; day 1) and berzosertib (140 mg/m2; days 2 and 9), in 21-day cycles. Berzosertib was well tolerated, with a similar toxicity profile to that reported previously for this combination. The overall response rate (90% confidence interval) was 23.4% (13.7, 35.8). No relevant associations were observed between response and gene alterations. Further studies combining ATR inhibitors with platinum compounds may be warranted in highly selected patient populations.

Molecular landscape of TP53 mutations in breast cancer and their utility for predicting the response to HER-targeted therapy in HER2 amplification-positive and HER2 mutation-positive amplification-negative patients

Purpose

We used targeted capture sequencing to analyze TP53‐mutated circulating tumor DNA (ctDNA) in metastatic breast cancer patients and to determine whether TP53 mutation has predictive value for anti‐human epidermal growth factor receptor 2 (HER2) treatment for in HER2 amplification‐positive patients (HER2+) and HER2 mutation‐positive, amplification‐negative (HER2−/mut) patients.

Patients and Methods

TP53 mutation features were analyzed in the Geneplus cohort (n = 1184). The MSK‐BREAST cohort was used to explore the value of TP53 mutation in predicting anti‐HER‐2 antibody efficacy. Sequencing of ctDNA in phase Ib, phase Ic, phase II clinical trials of pyrotinib (HER2+ patients), and an investigator‐initiated phase II study of pyrotinib (HER2−/mut patients) were performed to analyze the relationships between TP53 mutation and prognosis for HER2 TKIs. The MSK‐BREAST cohort, MutHER, and SUMMIT cohort were used for verification.

Results

TP53 mutations were detected in 53.1% (629/1184) of patients in the Geneplus cohort. The TP53 mutation rate was higher in HR‐negative (p < 0.001) and HER2 amplification‐positive (p = 0.015) patients. Among patients receiving anti‐HER2 antibody therapy, those whose tumors carried TP53 mutations had a shorter PFS (p = 0.004). However, the value of TP53 mutation in predicting HER2 TKI response was inconsistent. In HER2+ patients, no difference in PFS was observed among patients with different TP53 statuses in the combined analysis of the pyrotinib phase Ib, phase Ic, and phase II clinical trials (p = 1.00) or in the MSK‐BREAST cohort (p = 0.62). In HER2−/mut patients, TP53 mutation‐positive patients exhibited a trend toward worse prognosis with anti‐HER2 TKI treatment than TP53‐wild‐type patients in our investigator‐initiated phase II study (p = 0.15), and this trend was confirmed in the combined analysis of the MutHER and SUMMIT cohorts (p = 0.01).

Conclusions

TP53 mutation can be used to identify biomarkers of anti‐HER2 antibody drug resistance in HER2+ patients and HER2 TKI resistance in HER2−/mut patients.

Secretory pathway Ca2+-ATPase SPCA2 regulates mitochondrial respiration and DNA damage response through store-independent calcium entry

A complex interplay between the extracellular space, cytoplasm and individual organelles modulates Ca2+ signaling to impact all aspects of cell fate and function. In recent years, the molecular machinery linking endoplasmic reticulum stores to plasma membrane Ca2+ entry has been defined. However, the mechanism and pathophysiological relevance of store-independent modes of Ca2+ entry remain poorly understood. Here, we describe how the secretory pathway Ca2+-ATPase SPCA2 promotes cell cycle progression and survival by activating store-independent Ca2+ entry through plasma membrane Orai1 channels in mammary epithelial cells. Silencing SPCA2 expression or briefly removing extracellular Ca2+ increased mitochondrial ROS production, DNA damage and activation of the ATM/ATR-p53 axis leading to G0/G1 phase cell cycle arrest and apoptosis. Consistent with these findings, SPCA2 knockdown confers redox stress and chemosensitivity to DNA damaging agents. Unexpectedly, SPCA2-mediated Ca2+ entry into mitochondria is required for optimal cellular respiration and the generation of mitochondrial membrane potential. In hormone receptor positive (ER+/PR+) breast cancer subtypes, SPCA2 levels are high and correlate with poor survival prognosis. We suggest that elevated SPCA2 expression could drive pro-survival and chemotherapy resistance in cancer cells, and drugs that target store-independent Ca2+ entry pathways may have therapeutic potential in treating cancer.

Investigation of the Antitumor Effects of Tamoxifen and Its Ferrocene-Linked Derivatives on Pancreatic and Breast Cancer Cell Lines

Tamoxifen is a long-known anti-tumor drug, which is the gold standard therapy in estrogen receptor (ER) positive breast cancer patients. According to previous studies, the conjugation of the original tamoxifen molecule with different functional groups can significantly improve its antitumor effect. The purpose of this research was to uncover the molecular mechanisms behind the cytotoxicity of different ferrocene-linked tamoxifen derivates. Tamoxifen and its ferrocene-linked derivatives, T5 and T15 were tested in PANC1, MCF7, and MDA-MB-231 cells, where the incorporation of the ferrocene group improved the cytotoxicity on all cell lines. PANC1, MCF7, and MDA-MB-231 express ERα and GPER1 (G-protein coupled ER 1). However, ERβ is only expressed by MCF7 and MDA-MB-231 cells. Tamoxifen is a known agonist of GPER1, a receptor that can promote tumor progression. Analysis of the protein expression profile showed that while being cytotoxic, tamoxifen elevated the levels of different tumor growth-promoting factors (e.g., Bcl-XL, Survivin, EGFR, Cathepsins, chemokines). On the other hand, the ferrocene-linked derivates were able to lower these proteins. Further analysis showed that the ferrocene-linked derivatives significantly elevated the cellular oxidative stress compared to tamoxifen treatment. In conclusion, we were able to find two molecules possessing better cytotoxicity compared to their unmodified parent molecule while also being able to counter the negative effects of the presence of the GPER1 through the ER-independent mechanism of oxidative stress induction.

Association between TP53 mutation and high 21-gene recurrence score in estrogen receptor-positive/HER2-negative breast cancer

We investigated the association between TP53 mutation and 21-gene recurrence score (RS) in ER-positive/HER2-negative breast cancer (BC) using data from 141 patients who underwent TP53 sequencing and Oncotype DX^® tests. We detected TP53 mutations in 18 (12.8%) patients. Most patients with TP53 mutation had a high 21-gene RS (≥26). The average 21-gene RS was higher in TP53 mutant tumors. Multivariate analysis showed that mutated TP53 is an independent factor for a high 21-gene RS. Mutated TP53 remained closely associated with high 21-gene RS in patients with low pathological risk (n = 103). In the ER⁺/PR⁺/HER2-negative subset (n = 356) of The Cancer Genome Atlas, the non-luminal A intrinsic subtype was more prevalent in the group with mutant TP53. mRNA levels of p53-regulated senescence gatekeeper and cell cycle-related genes were increased in BC with mutated TP53. Mutational analysis of TP53 helped identify endocrine-resistant tumors.

Dissecting the heterogeneity and tumorigenesis of BRCA1 deficient mammary tumors via single cell RNA sequencing

Background: BRCA1 plays critical roles in mammary gland development and mammary tumorigenesis. And loss of BRCA1 induces mammary tumors in a stochastic manner. These tumors present great heterogeneity at both intertumor and intratumor levels.

Methods: To comprehensively elucidate the heterogeneity of BRCA1 deficient mammary tumors and the underlying mechanisms for tumor initiation and progression, we conducted bulk and single cell RNA sequencing (scRNA-seq) on both mammary gland cells and mammary tumor cells isolated from Brca1 knockout mice.

Results: We found the BRCA1 deficient tumors could be classified into four subtypes with distinct molecular features and different sensitivities to anti-cancer drugs at the intertumor level. Whereas within the tumors, heterogeneous subgroups were classified mainly due to the different activities of cell proliferation, DNA damage response/repair and epithelial-to-mesenchymal transition (EMT). Besides, we reconstructed the BRCA1 related mammary tumorigenesis to uncover the transcriptomes alterations during this process via pseudo-temporal analysis of the scRNA-seq data. Furthermore, from candidate markers for BRCA1 mutant tumors, we discovered and validated one oncogene Mrc2, whose loss could reduce mammary tumor growth in vitro and in vivo.

Conclusion: Our study provides a useful resource for better understanding of mammary tumorigenesis induced by BRCA1 deficiency.

TP53 mutations determined by targeted NGS in breast cancer: a case-control study

Background: Tumor protein 53 (TP53) gene mutations are identified in up to 37% of breast tumors especially in HER-2 positive and basal-like subtype. Previous studies have indicated TP53 mutations as a prognostic biomarker in breast cancer. However, most of these studies performed immunohistochemistry (IHC) for the detection of TP53 mutations.

Aim: The purpose of our study is to evaluate the role of TP53 somatic mutations detected via next-generation sequencing (NGS) as a potential prognostic marker in patients with breast cancer.

Materials and Methods: 82 female patients with Stage I–III breast cancer underwent NGS in paraffin blocks and blood samples during the period 25/09/2019 through 25/05/2021. 23 cases of somatic TP53 mutations and 23 cases of healthy controls were matched on age at diagnosis, menopausal status, histological subtype, histological grade, ki67 expression and disease stage.

Results: Mean age at diagnosis was 52.35 (SD; 11.47) years. The somatic TP53 mutation NM_000546.5:c.824G>A p.(Cys275Tyr) was most frequently detected. Co-existence of PIK3CA mutation was a common finding in somatic TP53-mutant tumors (4/23; 17.4%). Disease-free survival was shorter in TP53-mutated cases (16.3 months vs. 62.9 months). TP53 pathogenic somatic mutations were associated with a 8-fold risk of recurrence in the univariate Cox regression analysis (OR = 8.530, 95% CI: 1.81–40.117; p = 0.007).

Conclusions: Our case-control study suggests that TP53 somatic mutations detected by next-generation sequencing (NGS) are associated with an adverse prognosis in breast cancer.

Mucin Expression and Splicing Determine Novel Subtypes and Patient Mortality in Pancreatic Ductal Adenocarcinoma

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy demonstrating aberrant and progressive expression of mucins. The contribution of individual mucins has been extensively investigated in PDAC; however, comprehensive mucin profiling including splice variants in PDAC tumors has not been reported.

EXPERIMENTAL DESIGN

Using publicly available RNA sequencing (RNA-seq) datasets, we assess the expression of mucin family members and their splice variants (SV) in PDAC tumor samples for the first time. Mucin SVs that are correlated with PDAC patient survival are validated in a cohort of patient tumor samples. Further, we use computational methods to derive novel pancreatic tumor subtypes using mucin expression signatures and their associated activated pathways.

RESULTS

Principal component analysis identified four novel mucin-based PDAC subtypes. Pathway analysis implicated specific biological signatures for each subtype, labeled (i) immune activated, (ii) progressive, (iii) pancreatitis-initiated, and (iv) anti-inflammatory/PanIN-initiated. Assessing mucin SVs, significantly longer survival is observed with higher expression of 4 MUC1 and 1 MUC13 SVs, whereas patients expressing 2 MUC4 and 1 MUC16 SVs had shorter survival. Using a whole-transcriptome correlation, a three-gene panel, including ESRP2, PTK6, and MAGEH1, is designated to assess PDAC tumor sample cellularity by PCR. One MUC4 SV and one MUC13 SV are quantified in a separate PDAC patient cohort, and their effects on survival are experimentally validated.

CONCLUSIONS

Altogether, we demonstrate the unique expression pattern of mucins, four mucin-based PDAC subtypes, and the contribution of MUC1, MUC4, and MUC16 SVs in PDAC patient survival.

AC016405.3 functions as an oncogenic long non-coding RNA by regulating ERBB3 via sponging miR-22-3p in breast cancer

Background

Increasing studies reported that long non‐coding RNAs are involved in regulating breast cancer (BRCA) progression. However, the specific roles and mechanisms of lncRNAs in BRCA remain largely unknown. Here, we sought to explore the functions and mechanisms of AC016405.3 in BRCA progression.

Methods

Bioinformatic analysis for AC016405.3, miR‐22‐3p, and ERBB3 were performed on starBase. The expressions of AC016405.3, miR‐22‐3p, and ERBB3 were examined by RT‐qPCR. The functions of AC016405.3 on the proliferation, migration, and invasion of cells were evaluated by conducting CCK‐8, colony formation, wound‐healing, and Transwell assays. The subcellular distribution of AC016405.3 in BRCA cells was identified by performing fluorescence in situ hybridization (FISH) and subcellular fractionation techniques. Dual‐luciferase assay was applied to validate the interactions of miR‐22‐3p with AC016405.3 or ERBB3. The interaction between ERBB3 and miR‐22‐3p was also tested by Anti‐Ago2 RNA immunoprecipitation (RIP) assay.

Results

The results showed that AC016405.3 is highly expressed in BRCA tissues as well as cells and positively correlated with poor prognosis in BRCA patients. Silencing AC016405.3 obviously repressed the malignant behaviors of BRCA cells. Mechanistically, AC016405.3 functioned as a competing endogenous RNA (ceRNA) for miR‐22‐3p in the cytoplasm and sponged miR‐22‐3p to release its suppression of ERBB3. Rescue experiments revealed that the suppression role induced by AC016405.3 depletion on malignant behaviors of BRCA cells could be obviously counter by inhibiting miR‐22‐3p or overexpressing ERBB3.

Conclusion

AC016405.3 promotes BRCA progression by the derepression of ERBB3 via sponging miR‐22‐3p, which may represent a potential target for BRCA treatment.

Single Cell Genetic Profiling of Tumors of Breast Cancer Patients Aged 50 Years and Older Reveals Enormous Intratumor Heterogeneity Independent of Individual Prognosis

PURPOSE

Older breast cancer patients are underrepresented in cancer research even though the majority (81.4%) of women dying of breast cancer are 55 years and older. Here we study a common phenomenon observed in breast cancer which is a large inter- and intratumor heterogeneity; this poses a tremendous clinical challenge, for example with respect to treatment stratification. To further elucidate genomic instability and tumor heterogeneity in older patients, we analyzed the genetic aberration profiles of 39 breast cancer patients aged 50 years and older (median 67 years) with either short (median 2.4 years) or long survival (median 19 years). The analysis was based on copy number enumeration of eight breast cancer-associated genes using multiplex interphase fluorescence in situ hybridization (miFISH) of single cells, and by targeted next-generation sequencing of 563 cancer-related genes.

RESULTS

We detected enormous inter- and intratumor heterogeneity, yet maintenance of common cancer gene mutations and breast cancer specific chromosomal gains and losses. The gain of COX2 was most common (72%), followed by MYC (69%); losses were most prevalent for CDH1 (74%) and TP53 (69%). The degree of intratumor heterogeneity did not correlate with disease outcome. Comparing the miFISH results of diploid with aneuploid tumor samples significant differences were found: aneuploid tumors showed significantly higher average signal numbers, copy number alterations (CNAs) and instability indices. Mutations in PIKC3A were mostly restricted to luminal A tumors. Furthermore, a significant co-occurrence of CNAs of DBC2/MYC, HER2/DBC2 and HER2/TP53 and mutual exclusivity of CNAs of HER2 and PIK3CA mutations and CNAs of CCND1 and PIK3CA mutations were revealed.

CONCLUSION

Our results provide a comprehensive picture of genome instability profiles with a large variety of inter- and intratumor heterogeneity in breast cancer patients aged 50 years and older. In most cases, the distribution of chromosomal aneuploidies was consistent with previous results; however, striking exceptions, such as tumors driven by exclusive loss of chromosomes, were identified.

Genome-scale mechanistic modeling of signaling pathways made easy: A bioconductor/cytoscape/web server framework for the analysis of omic data

Genome-scale mechanistic models of pathways are gaining importance for genomic data interpretation because they provide a natural link between genotype measurements (transcriptomics or genomics data) and the phenotype of the cell (its functional behavior). Moreover, mechanistic models can be used to predict the potential effect of interventions, including drug inhibitions. Here, we present the implementation of a mechanistic model of cell signaling for the interpretation of transcriptomic data as an R/Bioconductor package, a Cytoscape plugin and a web tool with enhanced functionality which includes building interpretable predictors, estimation of the effect of perturbations and assessment of the effect of mutations in complex scenarios.

Oncogenic and Tumor Suppressive Components of the Cell Cycle in Breast Cancer Progression and Prognosis

Cancer, a disease of inappropriate cell proliferation, is strongly interconnected with the cell cycle. All cancers consist of an abnormal accumulation of neoplastic cells, which are propagated toward uncontrolled cell division and proliferation in response to mitogenic signals. Mitogenic stimuli include genetic and epigenetic changes in cell cycle regulatory genes and other genes which regulate the cell cycle. This suggests that multiple, distinct pathways of genetic alterations lead to cancer development. Products of both oncogenes (including cyclin-dependent kinase (CDKs) and cyclins) and tumor suppressor genes (including cyclin-dependent kinase inhibitors) regulate cell cycle machinery and promote or suppress cell cycle progression, respectively. The identification of cyclins and CDKs help to explain and understand the molecular mechanisms of cell cycle machinery. During breast cancer tumorigenesis, cyclins A, B, C, D1, and E; cyclin-dependent kinase (CDKs); and CDK-inhibitor proteins p16, p21, p27, and p53 are known to play significant roles in cell cycle control and are tightly regulated in normal breast epithelial cells. Following mitogenic stimuli, these components are deregulated, which promotes neoplastic transformation of breast epithelial cells. Multiple studies implicate the roles of both types of components-oncogenic CDKs and cyclins, along with tumor-suppressing cyclin-dependent inhibitors-in breast cancer initiation and progression. Numerous clinical studies have confirmed that there is a prognostic significance for screening for these described components, regarding patient outcomes and their responses to therapy. The aim of this review article is to summarize the roles of oncogenic and tumor-suppressive components of the cell cycle in breast cancer progression and prognosis.

First in class dual MDM2/MDMX inhibitor ALRN-6924 enhances antitumor efficacy of chemotherapy in TP53 wild-type hormone receptor-positive breast cancer models

BACKGROUND

MDM2/MDMX proteins are frequently elevated in hormone receptor-positive (ER+) breast cancer. We sought to determine the antitumor efficacy of the combination of ALRN-6924, a dual inhibitor of MDM2/MDMX, with chemotherapy in ER+ breast cancer models.

METHODS

Three hundred two cell lines representing multiple tumor types were screened to confirm the role of TP53 status in ALRN-6924 efficacy. ER+ breast cancer cell lines (MCF-7 and ZR-75-1) were used to investigate the antitumor efficacy of ALRN-6924 combination. In vitro cell proliferation, cell cycle, and apoptosis assays were performed. Xenograft tumor volumes were measured, and reverse-phase protein array (RPPA), immunohistochemistry (IHC), and TUNEL assay of tumor tissues were performed to evaluate the in vivo pharmacodynamic effects of ALRN-6924 with paclitaxel.

RESULTS

ALRN-6924 was active in wild-type TP53 (WT-TP53) cancer cell lines, but not mutant TP53. On ER+ breast cancer cell lines, it was synergistic in vitro and had enhanced in vivo antitumor activity with both paclitaxel and eribulin. Flow cytometry revealed signs of mitotic crisis in all treatment groups; however, S phase was only decreased in MCF-7 single agent and combinatorial ALRN-6924 arms. RPPA and IHC demonstrated an increase in p21 expression in both combinatorial and single agent ALRN-6924 in vivo treatment groups. Apoptotic assays revealed a significantly enhanced in vivo apoptotic rate in ALRN-6924 combined with paclitaxel treatment arm compared to either single agent.

CONCLUSION

The significant synergy observed with ALRN-6924 in combination with chemotherapeutic agents supports further evaluation in patients with hormone receptor-positive breast cancer.

bc-GenExMiner 4.5: new mining module computes breast cancer differential gene expression analyses

‘Breast cancer gene-expression miner’ (bc-GenExMiner) is a breast cancer–associated web portal (http://bcgenex.ico.unicancer.fr). Here, we describe the development of a new statistical mining module, which permits several differential gene expression analyses, i.e. ‘Expression’ module. Sixty-two breast cancer cohorts and one healthy breast cohort with their corresponding clinicopathological information are included in bc-GenExMiner v4.5 version. Analyses are based on microarray or RNAseq transcriptomic data. Thirty-nine differential gene expression analyses, grouped into 13 categories, according to clinicopathological and molecular characteristics (‘Targeted’ and ‘Exhaustive’) and gene expression (‘Customized’), have been developed. Output results are visualized in four forms of plots. This new statistical mining module offers, among other things, the possibility to compare gene expression in healthy (cancer-free), tumour-adjacent and tumour tissues at once and in three triple-negative breast cancer subtypes (i.e. C1: molecular apocrine tumours; C2: basal-like tumours infiltrated by immune suppressive cells and C3: basal-like tumours triggering an ineffective immune response). Several validation tests showed that bioinformatics process did not alter the pathobiological information contained in the source data. In this work, we developed and demonstrated that bc-GenExMiner ‘Expression’ module can be used for exploratory and validation purposes.

Database URL: http://bcgenex.ico.unicancer.fr

Human papillomavirus, gene mutation and estrogen and progesterone receptors in breast cancer: a cross-sectional study

Introduction

recent studies show a good relationship between breast cancer (BC) and human papillomaviruses (HPV) wich is responsible for about 18% of BC cases. This study aimed to assess the relationship between different genotypes of HPV and the expression of P53 and retinoblastoma (RB) genes and estrogen and progesterone receptors in BC among Sudanese women.

Methods

one hundred and fifty tissue blocks were obtained from females diagnosed with BC. Positive samples were used to determine genotypes with an applied biosystem (ABI 3730XL) genetic analyzer for sequencing and immunohistochemistry.

Results

13/150 samples showed HPV DNA. High-risk HPV-16 was detected in 5 cases, high-risk-HPV-58 was found in four cases, and HPV-18 was detected in three cases. Low-risk-HPV-11 was detected in a single invasive lobular carcinoma (ILC) case. P53 and RB gene mutations were detected in 35 and 30 BC cases, respectively. P53 gene mutation was frequently identified in grade (III) BC while RB gene mutation was positive in grade (II). Grade (II) BC had a higher incidence of HPV-16 and 58. On the other hand, HPV-18 had a higher incidence in grade (III). Estrogen and progesterone receptors were expressed in 94 and 79 HPV cases among the study group, respectively.

Conclusion

this study elucidates the associations between HPV genotypes and BC. A statistically significant association was observed among p53 and RB gene mutations and different BC histological types. On the other hand, there was a statistically insignificant association between HPV genotyping and different BC gradings, BC histological types, P53 and RB genes mutations, and estrogen and progesterone receptor expression. Also, there was a statistically insignificant association among estrogen and progesterone receptors expression and BC grading. RB gene mutation was significantly associated with different BC grades. On the other hand, there was a statistically insignificant association between progesterone receptor expression and BC.

The Use of Serial Circulating Tumor DNA to Detect Resistance Alterations in Progressive Metastatic Breast Cancer

PURPOSE

Circulating tumor DNA (ctDNA) is a promising tool for noninvasive longitudinal monitoring of genomic alterations. We analyzed serial ctDNA to characterize genomic evolution in progressive metastatic breast cancer.

EXPERIMENTAL DESIGN

This was a retrospective cohort between 2015 and 2019 obtained under an Institutional Review Board-approved protocol at Northwestern University (Chicago, IL). ctDNA samples were analyzed with Guardant360 next-generation sequencing (NGS) assay. A total of 86 patients had at least two serial ctDNA collections with the second drawn at first post-NGS progression (PN1) by imaging and clinical assessment. A total of 27 participants had ctDNA drawn at second post-NGS clinical progression (PN2). We analyzed alterations, mutant allele frequency (MAF), number of alterations (NOA), and sites of disease on imaging in close proximity to ctDNA evaluation. Matched pairs' variations in MAF, NOA, and alterations at progression were tested through Wilcoxon test. We identified an independent control cohort at Massachusetts General Hospital (Boston, MA) of 63 patients with serial ctDNA sampling and no evidence of progression.

RESULTS

We identified 44 hormone receptor-positive, 20 HER2⁺, and 22 triple-negative breast cancer cases. The significant alterations observed between baseline and PN1 were TP53 (P < 0.0075), PIK3CA (P < 0.0126), AR (P < 0.0126), FGFR1 (P < 0.0455), and ESR1 (P < 0.0143). Paired analyses revealed increased MAF and NOA from baseline to PN1 (P = 0.0026, and P < 0.0001, respectively). When compared with controls without progression, patients with ctDNA collection at times of progression were associated with increased MAF and NOA (P = 0.0042 and P < 0.0001, respectively).

CONCLUSIONS

Serial ctDNA testing identified resistance alterations and increased NOA and MAF were associated with disease progression. Prospective longitudinal ctDNA evaluation could potentially monitor tumor genomic evolution.

p53 Enhances Artemisia annua L. Polyphenols-Induced Cell Death Through Upregulation of p53-Dependent Targets and Cleavage of PARP1 and Lamin A/C in HCT116 Colorectal Cancer Cells

Plant-derived natural polyphenols exhibit anticancer activity without showing any noticeable toxicities to normal cells. The aim of this study was to investigate the role of p53 on the anticancer effect of polyphenols isolated from Korean Artemisia annua L. (pKAL) in HCT116 human colorectal cancer cells. We confirmed that pKAL induced reactive oxygen species (ROS) production, propidium iodide (PI) uptake, nuclear structure change, and acidic vesicles in a p53-independent manner in p53-null HCT116 cells through fluorescence microscopy analysis of DCF/PI-, DAPI-, and AO-stained cells. The pKAL-induced anticancer effects were found to be significantly higher in p53-wild HCT116 cells than in p53-null by hematoxylin staining, CCK-8 assay, Western blot, and flow cytometric analysis of annexin V/PI-stained cells. In addition, expression of ectopic p53 in p53-null cells was upregulated by pKAL in both the nucleus and cytoplasm, increasing pKAL-induced cell death. Moreover, Western bot analysis revealed that pKAL-induced cell death was associated with upregulation of p53-dependent targets such as p21, Bax and DR5 and cleavage of PARP1 and lamin A/C in p53-wild HCT116 cells, but not in p53-null. Taken together, these results indicate that p53 plays an important role in enhancing the anticancer effects of pKAL by upregulating p53 downstream targets and inducing intracellular cell death processes.

Triangular Relationship between p53, Autophagy, and Chemotherapy Resistance

Chemotherapy and radiation often induce a number of cellular responses, such as apoptosis, autophagy, and senescence. One of the major regulators of these processes is p53, an essential tumor suppressor that is often mutated or lost in many cancer types and implicated in early tumorigenesis. Gain of function (GOF) p53 mutations have been implicated in increased susceptibility to drug resistance, by compromising wildtype anti-tumor functions of p53 or modulating key p53 processes that confer chemotherapy resistance, such as autophagy. Autophagy, a cellular survival mechanism, is initially induced in response to chemotherapy and radiotherapy, and its cytoprotective nature became the spearhead of a number of clinical trials aimed to sensitize patients to chemotherapy. However, increased pre-clinical studies have exemplified the multifunctional role of autophagy. Additionally, compartmental localization of p53 can modulate induction or inhibition of autophagy and may play a role in autophagic function. The duality in p53 function and its effects on autophagic function are generally not considered in clinical trial design or clinical therapeutics; however, ample pre-clinical studies suggest they play a role in tumor responses to therapy and drug resistance. Further inquiry into the interconnection between autophagy and p53, and its effects on chemotherapeutic responses may provide beneficial insights on multidrug resistance and novel treatment regimens for chemosensitization.

p53, ER, and Ki67 Expression in Canine Mammary Carcinomas and Correlation With Pathological Variables and Prognosis

Using immunohistochemistry, 170 canine mammary carcinomas were evaluated for p53, ER (estrogen receptor), and Ki67. Of the 170 tumors, 89 were grade I (52.3%), 36 were grade II (21.2%), and 45 were grade III (26.4%). Eight cases (0.5%) were positive for p53 and 69/170 cases (40.5%) were positive for ER. Ki67 values were 24 ± 18% (mean ± SD). Using a cutoff value of 33.3% Ki67-positive neoplastic nuclei, 38/159 (23.8%) were classified as high proliferative and 121/159 (76.2%) as low proliferative. p53-positive cases had significantly higher Ki67 expression and higher histological grade. ER expression was not correlated with p53 expression but was significantly related to low Ki67 values and low histological grade. Moreover, ER-positive cases had significantly longer survival compared to ER-negative tumors, and ER expression had better correlation with tumor-related survival than histological grade. In summary, p53 accumulated in a small subset of canine mammary tumors and was associated with higher proliferative activity and higher histological grade. ER expression was confirmed as a differentiation marker associated with more favorable prognosis and biological behavior. The combined use of these 3 markers could be used in addition to histological grade to predict the biological behavior of canine mammary carcinomas.