TP73 is a member of the TP53 gene family and produces N- and C-terminal protein isoforms through alternative promoters, alternative translation initiation and alternative splicing. Most notably, p73 protein isoforms may either contain a p53-like transactivation domain (TAp73 isoforms) or lack this domain (ΔTAp73 isoforms) and these variants have opposing or independent functions. To date, there is a lack of well-characterised isoform-specific p73 antibodies. Here, we produced polyclonal and monoclonal antibodies to N-terminal p73 variants and the C-terminal p73α isoform, the most common variant in human tissues. These reagents show that TAp73 is a marker of multiciliated epithelial cells, while ΔTAp73 is a marker of non-proliferative basal/reserve cells in squamous epithelium. We were unable to detect ΔNp73 variant proteins, in keeping with recent data that this is a minor form in human tissues. Most cervical squamous cell carcinomas (79%) express p73α, and the distribution of staining in basal cells correlated with lower tumour grade. TAp73 was found in 17% of these tumours, with a random distribution and no association with clinicopathological features. These data indicate roles for ΔTAp73 in maintaining a non-proliferative state of undifferentiated squamous epithelial cells and for TAp73 in the production of differentiated multiciliated cells.

• Klíčová slova
• Cervical cancer, Endometrium, Fallopian tube, Multiciliated cells, Squamous epithelial stem cells, p73 isoforms,
• MeSH
• epitelové buňky metabolismus   MeSH
• lidé MeSH
• monoklonální protilátky MeSH
• nádorové buněčné linie MeSH
• nádory děložního čípku metabolismus   patologie   genetika   MeSH
• nádory metabolismus   patologie   genetika   MeSH
• protein - isoformy * metabolismus   genetika   MeSH
• protein p73 * metabolismus   genetika   MeSH
• spinocelulární karcinom metabolismus   patologie   genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• delta Np73 protein, human MeSH Prohlížeč
• monoklonální protilátky MeSH
• protein - isoformy * MeSH
• protein p73 * MeSH
• TP73 protein, human MeSH Prohlížeč

The p53 family of proteins evolved from a common ancestor into three separate genes encoding proteins that act as transcription factors with distinct cellular roles. Isoforms of each member that lack specific regions or domains are suggested to result from alternative transcription start sites, alternative splicing or alternative translation initiation, and have the potential to exponentially increase the functional repertoire of each gene. However, evidence supporting the presence of individual protein variants at functional levels is often limited and is inferred by mRNA detection using highly sensitive amplification techniques. We provide a critical appraisal of the current evidence for the origins, expression, functions and regulation of p53-family isoforms. We conclude that despite the wealth of publications, several putative isoforms remain poorly established. Future research with improved technical approaches and the generation of isoform-specific protein detection reagents is required to establish the physiological relevance of p53-family isoforms in health and disease. In addition, our analyses suggest that p53-family variants evolved partly through convergent rather than divergent evolution from the ancestral gene.

• MeSH
• alternativní sestřih * MeSH
• lidé MeSH
• messenger RNA metabolismus   genetika   MeSH
• molekulární evoluce MeSH
• nádorový supresorový protein p53 * metabolismus   genetika   MeSH
• počátek transkripce MeSH
• protein - isoformy * genetika   metabolismus   MeSH
• regulace genové exprese MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• messenger RNA MeSH
• nádorový supresorový protein p53 * MeSH
• protein - isoformy * MeSH

The TP63 gene encodes two major protein variants; TAp63 contains a p53-like transcription domain and consequently has tumor suppressor activities whereas ΔNp63 lacks this domain and acts as an oncogene. The two variants show distinct expression patterns in normal tissues and tumors, with lymphocytes and lymphomas/leukemias expressing TAp63, and basal epithelial cells and some carcinomas expressing high levels of ΔNp63, most notably squamous cell carcinomas (SCC). Whilst the transcriptional functions of TAp63 and ΔNp63 isoforms are known, the mechanisms involved in their regulation are poorly understood. Using squamous epithelial cells that contain high levels of ΔNp63 and low/undetectable TAp63, the DNA demethylating agent decitabine (5-aza-2'-deoxycytidine, 5-dAza) caused a dose-dependent increase in TAp63, with a simultaneous reduction in ΔNp63, indicating DNA methylation-dependent regulation at the isoform-specific promoters. The basal cytokeratin KRT5, a direct ΔNp63 transcriptional target, was also reduced, confirming functional alteration of p63 activity after DNA demethylation. We also showed high level methylation of three CpG sites in the TAP63 promoter in these cells, which was reduced by decitabine. DNMT1 depletion using inducible shRNAs partially replicated these effects, including an increase in the ratio of TAP63:ΔNP63 mRNAs, a reduction in ΔNp63 protein and reduced KRT5 mRNA levels. Finally, high DNA methylation levels were found at the TAP63 promoter in clinical SCC samples and matched normal tissues. We conclude that DNA methylation at the TAP63 promoter normally silences transcription in squamous epithelial cells, indicating DNA methylation as a therapeutic approach to induce this tumor suppressor in cancer. That decitabine simultaneously reduced the oncogenic activity of ΔNp63 provides a "double whammy" for SCC and other p63-positive carcinomas. Whilst a variety of mechanisms may be involved in producing the opposite effects of DNA demethylation on TAp63 and ΔNp63, we propose an "either or" mechanism in which TAP63 transcription physically interferes with the ability to initiate transcription from the downstream ΔNP63 promoter on the same DNA strand. This mechanism can explain the observed inverse expression of p63 isoforms in normal cells and cancer.

• Klíčová slova
• DNA methylation, TAp63, alternative promoter usage, decitabine, keratinocytes, squamous cell carcinoma, ΔNp63,
• Publikační typ
• časopisecké články MeSH

Like other malignancies, prostate tumors are thought to contain cancer stem-like cells (CSCs) that are responsible for growth, metastasis, and therapy resistance. ΔNp63 (also called p40) is a regulator of normal prostate stem/progenitor cell activities and a marker of normal basal epithelial cells. The levels of ΔNp63 are reduced in prostate adenocarcinomas, although there is also evidence that ΔNp63 is involved in CSC regulation and drives metastasis to the bone. We studied metastatic deposits of prostate cancers with isoform-specific ΔNp63 and TAp63 antibodies. We identified p63-positive cells in only 3 of 42 metastatic prostate tumors (7%), including 2/38 (5.3%) "usual-type" adenocarcinomas. ΔNp63 and TAp63 isoforms were present in the nuclei of a small subpopulation (< 1%) of tumor cells in these metastases. ΔNp63-positive cells showed a basal-like cell phenotype (cytokeratin 8- and androgen receptor-negative, high molecular weight cytokeratin- and cytokeratin 19-positive), distinct from the tumor bulk. TAp63-positive cells were similar but were sometimes cytokeratin 8-positive. A subset of ΔNp63-positive tumor cells were CD44-positive, a marker of "basal" CSCs but were not positive for the "epithelial" CSC marker ALDH1. TAp63 was not associated with either of these CSC markers. None of the tumors containing p63-positive cells showed evidence of bone metastasis, compared with 28% of the p63-negative tumors. These data show that both ΔNp63 and TAp63 are present in only a small proportion of prostate adenocarcinomas and do not associate with metastasis. The data suggest heterogeneity of CSCs in prostate cancer, similar to other cancer types.

• Klíčová slova
• CD44, Cancer stem cells, Metastasis, Prostate cancer, p40, p63,
• MeSH
• adenokarcinom metabolismus   sekundární   MeSH
• dospělí MeSH
• fenotyp MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádorové biomarkery metabolismus   MeSH
• nádorové kmenové buňky metabolismus   patologie   MeSH
• nádorové supresorové proteiny metabolismus   MeSH
• nádory kostí metabolismus   sekundární   MeSH
• nádory prostaty metabolismus   patologie   MeSH
• retrospektivní studie MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• studie případů a kontrol MeSH
• transkripční faktory metabolismus   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• nádorové biomarkery MeSH
• nádorové supresorové proteiny MeSH
• TP63 protein, human MeSH Prohlížeč
• transkripční faktory MeSH

Hepatocyte dedifferentiation is a major source of hepatocellular carcinoma (HCC), but its mechanisms are unknown. We explored the p73 expression in HCC tumors and studied the effects of transcriptionally active p73β (TAp73β) in HCC cells. Expression profiles of p73 and patient clinical data were collected from the Genomic Data Commons (GDC) data portal and the TSVdb database, respectively. Global gene expression profiles were determined by pan-genomic 54K microarrays. The Gene Set Enrichment Analysis method was used to identify TAp73β-regulated gene sets. The effects of TAp73 isoforms were analyzed in monolayer cell culture, 3D-cell culture and xenograft models in zebrafish using western blot, flow cytometry, fluorescence imaging, real-time polymerase chain reaction (RT-PCR), immunohistochemistry and morphological examination. TAp73 isoforms were significantly upregulated in HCC, and high p73 expression correlated with poor patient survival. The induced expression of TAp73β caused landscape expression changes in genes involved in growth signaling, cell cycle, stress response, immunity, metabolism and development. Hep3B cells overexpressing TAp73β had lost hepatocyte lineage biomarkers including ALB, CYP3A4, AFP, HNF4α. In contrast, TAp73β upregulated genes promoting cholangiocyte lineage such as YAP, JAG1 and ZO-1, accompanied with an increase in metastatic ability. Our findings suggest that TAp73β may promote malignant dedifferentiation of HCC cells.

• Klíčová slova
• TAp73, dedifferentiation, hepatocellular carcinoma, metastasis, yes-associated protein 1, zebrafish,
• Publikační typ
• časopisecké články MeSH

ΔNp63, also known as p40, regulates stemness of normal mammary gland epithelium and provides stem cell characteristics in basal and HER2-driven murine breast cancer models. Whilst ΔNp63/p40 is a characteristic feature of normal basal cells and basal-type triple-negative breast cancer, some receptor-positive breast cancers express ΔNp63/p40 and its overexpression imparts cancer stem cell-like properties in ER+ cell lines. However, the incidence of ER+ and HER2+ tumours that express ΔNp63/p40 is unclear and the phenotype of ΔNp63/p40+ cells in these tumours remains uncertain. Using immunohistochemistry with p63 isoform-specific antibodies, we identified a ΔNp63/p40+ tumour cell subpopulation in 100 of 173 (58%) non-triple negative breast cancers and the presence of this population associated with improved survival in patients with ER- /HER2+ tumours (p = 0.006). Furthermore, 41% of ER+ /PR+ and/or HER2+ locally metastatic breast cancers expressed ΔNp63/p40, and these cells commonly accounted for <1% of the metastatic tumour cell population that localised to the tumour/stroma interface, exhibited an undifferentiated phenotype and were CD44+ /ALDH- . In vitro studies revealed that MCF7 and T47D (ER+ ) and BT-474 (HER2+ ) breast cancer cell lines similarly contained a small subpopulation of ΔNp63/p40+ cells that increased in mammospheres. In vivo, MCF7 xenografts contained ΔNp63/p40+ cells with a similar phenotype to primary ER+ cancers. Consistent with tumour samples, these cells also showed a distinct location at the tumour/stroma interface, suggesting a role for paracrine factors in the induction or maintenance of ΔNp63/p40. Thus, ΔNp63/p40 is commonly present in a small population of tumour cells with a distinct phenotype and location in ER+ and/or HER2+ human breast cancers.

• Klíčová slova
• CD44, HER2, aldehyde dehydrogenase, breast, cancer stem cells, oestrogen receptor, p40, p63, ΔNp63,
• MeSH
• fenotyp MeSH
• heterografty MeSH
• lidé MeSH
• myši MeSH
• nádorové biomarkery analýza   metabolismus   MeSH
• nádorové kmenové buňky metabolismus   patologie   MeSH
• nádorové supresorové proteiny metabolismus   MeSH
• nádory prsu genetika   metabolismus   patologie   MeSH
• receptor erbB-2 genetika   metabolismus   MeSH
• receptory pro estrogeny genetika   metabolismus   MeSH
• transkripční faktory metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ERBB2 protein, human MeSH Prohlížeč
• nádorové biomarkery MeSH
• nádorové supresorové proteiny MeSH
• receptor erbB-2 MeSH
• receptory pro estrogeny MeSH
• TP63 protein, human MeSH Prohlížeč
• transkripční faktory MeSH

Signal Transducer and Activator of Transcription 3 (STAT3) is a transcription factor with many important functions in the biology of normal and transformed cells. Its regulation is highly complex as it is involved in signaling pathways in many different cell types and under a wide variety of conditions. Besides other functions, STAT3 is an important regulator of normal stem cells and cancer stem cells. p63 which is a member of the p53 protein family is also involved in these functions and is both physically and functionally connected with STAT3. This review summarizes STAT3 function and regulation, its role in stem cell and cancer stem cell properties and highlights recent reports about its relationship to p63.

• Klíčová slova
• Cancer stem cells, STAT3, Stem cells, p63,
• MeSH
• fosforylace MeSH
• lidé MeSH
• lidské embryonální kmenové buňky metabolismus   MeSH
• metylace MeSH
• mikro RNA metabolismus   MeSH
• myší embryonální kmenové buňky metabolismus   MeSH
• myši MeSH
• nádorové kmenové buňky metabolismus   MeSH
• nádorové supresorové proteiny chemie   metabolismus   MeSH
• nádory metabolismus   MeSH
• přeprogramování buněk MeSH
• transkripční faktor STAT3 chemie   metabolismus   MeSH
• transkripční faktory chemie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• mikro RNA MeSH
• nádorové supresorové proteiny MeSH
• TP63 protein, human MeSH Prohlížeč
• transkripční faktor STAT3 MeSH
• transkripční faktory MeSH

The TP63 gene encodes two major protein variants that differ in their N-terminal sequences and have opposing effects. In breast, ΔNp63 is expressed by immature stem/progenitor cells and mature myoepithelial/basal cells and is a characteristic feature of basal-like triple-negative breast cancers (TNBCs). The expression and potential role of TAp63 in the mammary gland and breast cancers is less clear, partly due to the lack of studies that employ p63 isoform-specific antibodies. We used immunohistochemistry with ΔNp63-specific or TAp63-specific monoclonal antibodies to investigate p63 isoforms in 236 TNBCs. TAp63, but not ΔNp63, was seen in tumour-associated lymphocytes and other stromal cells. Tumour cells showed nuclear staining for ΔNp63 in 17% of TNBCs compared to 7.3% that were positive for TAp63. Whilst most TAp63+ tumours also contained ΔNp63+ cells, the levels of the two isoforms were independent of each other. ΔNp63 associated with metaplastic and medullary cancers, and with a basal phenotype, whereas TAp63 associated with androgen receptor, BRCA1/2 wild-type status and PTEN positivity. Despite the proposed effects of p63 on proliferation, Ki67 did not correlate with either p63 isoform, nor did they associate with p53 mutation status. ΔNp63 showed no association with patient outcomes, whereas TAp63+ patients showed fewer recurrences and improved overall survival. These findings indicate that both major p63 protein isoforms are expressed in TNBCs with different tumour characteristics, indicating distinct functional activities of p63 variants in breast cancer. Analysis of individual p63 isoforms provides additional information into TNBC biology, with TAp63 expression indicating improved prognosis.

• Klíčová slova
• Androgen receptor, BRCA1, BRCA2, PTEN, TAp63, Triple-negative breast cancer, ΔNp63,
• MeSH
• fenotyp MeSH
• fosfohydroláza PTEN genetika   MeSH
• lidé MeSH
• lokální recidiva nádoru genetika   MeSH
• mutace genetika   MeSH
• nádorové supresorové proteiny genetika   MeSH
• protein - isoformy genetika   MeSH
• protein BRCA1 genetika   MeSH
• protein BRCA2 genetika   MeSH
• regulace genové exprese u nádorů genetika   MeSH
• transkripční faktory genetika   MeSH
• triple-negativní karcinom prsu genetika   metabolismus   mortalita   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• BRCA1 protein, human MeSH Prohlížeč
• BRCA2 protein, human MeSH Prohlížeč
• fosfohydroláza PTEN MeSH
• nádorové supresorové proteiny MeSH
• protein - isoformy MeSH
• protein BRCA1 MeSH
• protein BRCA2 MeSH
• PTEN protein, human MeSH Prohlížeč
• TP63 protein, human MeSH Prohlížeč
• transkripční faktory MeSH

BACKGROUND: p63, a member of the p53 protein family, plays key roles in epithelial development and carcinogenesis. In breast cancer, p63 expression has been found predominantly in basal-A (epithelial-type) triple-negative breast carcinomas (TNBC). To investigate the functional role of p63 in basal-A TNBC, we created MDA-MB-468 cell lines with inducible expression of the two major N-terminal p63 isoforms, TAp63α and ∆Np63α. RESULTS: TAp63α did not have significant effect on gene expression profile and cell phenotype, whilst the main effect of ΔNp63α was reduction of cell adhesion. Gene expression profiling revealed genes involved in cell adhesion and migration whose expression relies on overexpression of ΔNp63α. Reduced cell adhesion also led to decreased cell proliferation in vitro and in vivo. Similar data were obtained in another basal-A cell line, BT-20, but not in BT-549 basal-B (mesenchymal-like) TNBC cells. CONCLUSIONS: In basal-A TNBC cells, ∆Np63α has much stronger effects on gene expression than TAp63α. Although p63 is mentioned mostly in connection with breast cell differentiation and stem cell regulation, we showed that a major effect of p63 is regulation of cell adhesion, a process important in metastasis and invasion of tumour cells. That this effect is not seen in mesenchymal-type TNBC cells suggests lineage-dependent functions, mirroring the expression of ∆Np63α in primary human breast cancers.

• Klíčová slova
• Adhesion, Triple-negative breast cancer, p63 isoforms,
• MeSH
• buněčná adheze genetika   MeSH
• buněčný cyklus genetika   MeSH
• exprese genu * MeSH
• heterografty MeSH
• kultivované buňky MeSH
• lidé MeSH
• modely nemocí na zvířatech MeSH
• nádorové buněčné linie MeSH
• nádorové supresorové proteiny genetika   MeSH
• proliferace buněk MeSH
• protein - isoformy MeSH
• stanovení celkové genové exprese MeSH
• transkripční faktory genetika   MeSH
• triple-negativní karcinom prsu genetika   patologie   MeSH
• viabilita buněk genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• nádorové supresorové proteiny MeSH
• protein - isoformy MeSH
• TP63 protein, human MeSH Prohlížeč
• transkripční faktory MeSH

Triple-negative breast cancers (TNBC) comprise a heterogeneous subgroup of tumors with a generally poor prognosis. Subclassification of TNBC based on genomic analyses shows that basal-like TNBCs, specifically the basal A or BL2 subtype, are characterized by the expression of ΔNp63, a transcription factor that has been attributed a variety of roles in the regulation of proliferation, differentiation, and cell survival. To investigate the role(s) of p63 in basal-like breast cancers, we used HCC1806 cells that are classified as basal A/BL2. We show that these cells endogenously express p63, mainly as the ΔNp63α isoform. TP63 gene knockout by CRISPR resulted in viable cells that proliferate more slowly and adhere less tightly, with an increased rate of migration. Analysis of adhesion-related gene expression revealed a complex set of alterations in p63-depleted cells, with both increased and decreased adhesion molecules and adhesion substrates compared to parental cells expressing p63. Examination of the phenotype of these cells indicated that endogenous p63 is required to suppress the expression of luminal markers and maintain the basal epithelial phenotype, with increased levels of both CK8 and CK18 and a reduction in N-cadherin levels in cells lacking p63. On the other hand, the level of CK5 was not decreased and ER was not increased, indicating that p63 loss is insufficient to induce full luminal-type differentiation. Taken together, these data demonstrate that p63 exerts multiple pro-oncogenic effects on cell differentiation, proliferation and adhesion in basal-like breast cancers.

• Klíčová slova
• Adhesion, Basal-like breast cancer, Differentiation, p63,
• MeSH
• buněčná adheze MeSH
• buněčná diferenciace MeSH
• CD antigeny biosyntéza   genetika   MeSH
• CRISPR-Cas systémy MeSH
• epitelové buňky metabolismus   patologie   MeSH
• fenotyp MeSH
• genový knockout MeSH
• kadheriny biosyntéza   genetika   MeSH
• karcinom patologie   MeSH
• keratiny biosyntéza   genetika   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nádorové proteiny fyziologie   MeSH
• nádorové supresorové proteiny nedostatek   fyziologie   MeSH
• proliferace buněk MeSH
• protein - isoformy fyziologie   MeSH
• regulace genové exprese u nádorů MeSH
• transkripční faktory nedostatek   fyziologie   MeSH
• triple-negativní karcinom prsu patologie   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• CD antigeny MeSH
• CDH2 protein, human MeSH Prohlížeč
• kadheriny MeSH
• keratiny MeSH
• nádorové proteiny MeSH
• nádorové supresorové proteiny MeSH
• protein - isoformy MeSH
• TP63 protein, human MeSH Prohlížeč
• transkripční faktory MeSH