Prominin-1 (CD133) is a cholesterol-binding membrane glycoprotein selectively associated with highly curved and prominent membrane structures. It is widely recognized as an antigenic marker of stem cells and cancer stem cells and is frequently used to isolate them from biological and clinical samples. Recent progress in understanding various aspects of CD133 biology in different cell types has revealed the involvement of CD133 in the architecture and dynamics of plasma membrane protrusions, such as microvilli and cilia, including the release of extracellular vesicles, as well as in various signaling pathways, which may be regulated in part by posttranslational modifications of CD133 and its interactions with a variety of proteins and lipids. Hence, CD133 appears to be a master regulator of cell signaling as its engagement in PI3K/Akt, Src-FAK, Wnt/β-catenin, TGF-β/Smad and MAPK/ERK pathways may explain its broad action in many cellular processes, including cell proliferation, differentiation, and migration or intercellular communication. Here, we summarize early studies on CD133, as they are essential to grasp its novel features, and describe recent evidence demonstrating that this unique molecule is involved in membrane dynamics and molecular signaling that affects various facets of tissue homeostasis and cancer development. We hope this review will provide an informative resource for future efforts to elucidate the details of CD133's molecular function in health and disease.
BACKGROUND: ΔNp63 overexpression is a common event in squamous cell carcinoma (SCC) that contributes to tumorigenesis, making ΔNp63 a potential target for therapy. METHODS: We created inducible TP63-shRNA cells to study the effects of p63-depletion in SCC cell lines and non-malignant HaCaT keratinocytes. DNA damaging agents, growth factors, signaling pathway inhibitors, histone deacetylase inhibitors, and metabolism-modifying drugs were also investigated for their ability to influence ΔNp63 protein and mRNA levels. RESULTS: HaCaT keratinocytes, FaDu and SCC-25 cells express high levels of ΔNp63. HaCaT and FaDu inducible TP63-shRNA cells showed reduced proliferation after p63 depletion, with greater effects on FaDu than HaCaT cells, compatible with oncogene addiction in SCC. Genotoxic insults and histone deacetylase inhibitors variably reduced ΔNp63 levels in keratinocytes and SCC cells. Growth factors that regulate proliferation/survival of squamous cells (IGF-1, EGF, amphiregulin, KGF, and HGF) and PI3K, mTOR, MAPK/ERK or EGFR inhibitors showed lesser and inconsistent effects, with dual inhibition of PI3K and mTOR or EGFR inhibition selectively reducing ΔNp63 levels in HaCaT cells. In contrast, the antihyperlipidemic drug lovastatin selectively increased ΔNp63 in HaCaT cells. CONCLUSIONS: These data confirm that ΔNp63-positive SCC cells require p63 for continued growth and provide proof of concept that p63 reduction is a therapeutic option for these tumors. Investigations of ΔNp63 regulation identified agent-specific and cell-specific pathways. In particular, dual inhibition of the PI3K and mTOR pathways reduced ΔNp63 more effectively than single pathway inhibition, and broad-spectrum histone deacetylase inhibitors showed a time-dependent biphasic response, with high level downregulation at the transcriptional level within 24 h. In addition to furthering our understanding of ΔNp63 regulation in squamous cells, these data identify novel drug combinations that may be useful for p63-based therapy of SCC.
- MeSH
- inhibitory histondeacetylas MeSH
- karcinogeneze MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- nádorové supresorové proteiny metabolismus MeSH
- nádorový supresorový protein p53 * genetika MeSH
- rodina MeSH
- spinocelulární karcinom * farmakoterapie genetika metabolismus MeSH
- transkripční faktory metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Since the discovery of the first MDM2 inhibitors, we have gained deeper insights into the cellular roles of MDM2 and p53. In this review, we focus on MDM2 inhibitors that bind to the p53-binding domain of MDM2 and aim to disrupt the binding of MDM2 to p53. We describe the basic mechanism of action of these MDM2 inhibitors, such as nutlin-3a, summarise the determinants of sensitivity to MDM2 inhibition from p53-dependent and p53-independent points of view and discuss the problems with innate and acquired resistance to MDM2 inhibition. Despite progress in MDM2 inhibitor design and ongoing clinical trials, their broad use in cancer treatment is not fulfilling expectations in heterogenous human cancers. We assess the MDM2 inhibitor types in clinical trials and provide an overview of possible sources of resistance to MDM2 inhibition, underlining the need for patient stratification based on these aspects to gain better clinical responses, including the use of combination therapies for personalised medicine.
- MeSH
- antitumorózní látky farmakologie MeSH
- bakteriální léková rezistence účinky léků fyziologie MeSH
- cílená molekulární terapie metody MeSH
- klinické zkoušky jako téma MeSH
- lidé MeSH
- nádorový supresorový protein p53 antagonisté a inhibitory genetika metabolismus MeSH
- nádory farmakoterapie MeSH
- protoonkogenní proteiny c-mdm2 antagonisté a inhibitory genetika metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Background: The links between the p53/MDM2 pathway and the expression of pro-oncogenic immune inhibitory receptors in tumor cells are undefined. In this report, we evaluate whether there is p53 and/or MDM2 dependence in the expression of two key immune receptors, CD276 and PD-L1. Methods: Proximity ligation assays were used to quantify protein-protein interactions in situ in response to Nutlin-3. A panel of p53-null melanoma cells was created using CRISPR-Cas9 guide RNA mediated genetic ablation. Flow cytometric analyses were used to assess the impact of TP53 or ATG5 gene ablation, as well as the effects of Nutlin-3 and an ATM inhibitor on cell surface PD-L1 and CD276. Targeted siRNA was used to deplete CD276 to assess changes in cell cycle parameters by flow cytometry. A T-cell proliferation assay was used to assess activity of CD4+ T-cells as a function of ATG5 genotype. Results: CD276 forms protein-protein interactions with MDM2 in response to Nutlin-3, similar to the known MDM2 interactors p53 and HSP70. Isogenic HCT116 p53-wt/null cancer cells demonstrated that CD276 is induced on the cell surface by Nutlin-3 in a p53-dependent manner. PD-L1 was also unexpectedly induced by Nutlin-3, but PD-L1 does not bind MDM2. The ATM inhibitor KU55993 reduced the levels of PD-L1 under conditions where Nutlin-3 induces PD-L1, indicating that MDM2 and ATM have opposing effects on PD-L1 steady-state levels. PD-L1 is also up-regulated in response to genetic ablation of TP53 in A375 melanoma cell clones under conditions in which CD276 remains unaffected. A549 cells with a deletion in the ATG5 gene up-regulated only PD-L1, further indicating that PD-L1 and CD276 are under distinct genetic control. Conclusion: Genetic inactivation of TP53, or the use of the MDM2 ligand Nutlin-3, alters the expression of the immune blockade receptors PD-L1 and CD276. The biological function of elevated CD276 is to promote altered cell cycle progression in response to Nutlin-3, whilst the major effect of elevated PD-L1 is T-cell suppression. These data indicate that TP53 gene status, ATM and MDM2 influence PD-L1 and CD276 paralogs on the cell surface. These data have implications for the use of drugs that target the p53 pathway as modifiers of immune checkpoint receptor expression.
- MeSH
- antigeny B7 genetika MeSH
- antigeny CD274 genetika MeSH
- buněčný cyklus účinky léků genetika MeSH
- buňky A549 MeSH
- HCT116 buňky MeSH
- imidazoly farmakologie MeSH
- lidé MeSH
- ligandy MeSH
- melanom farmakoterapie MeSH
- nádorové buněčné linie MeSH
- nádorový supresorový protein p53 genetika MeSH
- piperaziny farmakologie MeSH
- proliferace buněk účinky léků genetika MeSH
- protoonkogenní proteiny c-mdm2 genetika MeSH
- upregulace účinky léků genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články 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.
- 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
Activation of the Hsp90 chaperone system is a characteristic of cancer cells. The regulation of chaperone activities involves their interaction with cochaperones; therefore we investigated the expression of Hsp70 and Hsp90 and their specific co-chaperones HOP and CHIP in cancer cell lines and primary cancers. Inhibition of Hsp90 by 17AAG increased the levels of Hsp70, Hsp90 and HOP but not CHIP mRNA in cancer cells. These changes are linked to activation of the HSF1 transcription factor and we show that the HOP promoter contains HSF1 binding sites, and that HSF1 binding to the HOP promoter is increased following 17AAG. The lack of alteration in the co-chaperone CHIP is explained by a lack of HSF response elements in the CHIP promoter. Non-proliferating cells expressed higher levels of CHIP and lower HOP, Hsp70 and Hsp90 levels compared to proliferating cells. Decreased expression of CHIP in proliferating cancer cells is in keeping with its proposed tumor suppressor properties, while over-expression of HOP in proliferating cells may contribute to excessive Hsp90 activity and stabilization of client proteins in tumors. In a panel of colorectal cancer samples, increased expression of Hsp70 and an increased ratio of HOP to CHIP were found, and were associated with decreased median survival. These data indicate that multiple changes occur in the chaperone/co-chaperone system in cancer that impact patient survival. It is likely that the ability to identify individual alterations to this system will be beneficial for treatment strategy decisions, particularly those that employ chaperone inhibitors.
- MeSH
- benzochinony farmakologie MeSH
- DNA vazebné proteiny genetika metabolismus MeSH
- HCT116 buňky MeSH
- homeodoménové proteiny genetika metabolismus MeSH
- Kaplanův-Meierův odhad MeSH
- lidé MeSH
- makrocyklické laktamy farmakologie MeSH
- nádorové supresorové proteiny genetika metabolismus MeSH
- nádory tračníku metabolismus MeSH
- prognóza MeSH
- proliferace buněk účinky léků MeSH
- promotorové oblasti (genetika) účinky léků MeSH
- proteiny tepelného šoku HSP70 genetika metabolismus MeSH
- proteiny tepelného šoku HSP90 antagonisté a inhibitory genetika metabolismus MeSH
- regulace genové exprese u nádorů účinky léků MeSH
- responzivní elementy genetika MeSH
- transkripční faktory genetika metabolismus MeSH
- ubikvitinligasy genetika metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Pharmacological inhibition of protein kinases that are responsible for the phosphorylation of the carboxy-terminal domain (CTD) of RNA Pol II during transcription by 5,6-dichloro-1-beta-D-ribofuranosyl-benzimidazole (DRB) leads to severe inhibition of mRNA synthesis and activates p53. Transcription of the p53 effectors that are induced under these conditions, such as p21 or PUMA, must bypass the requirement for CTD phosphorylation by the positive elongation factor P-TEFb. Here, we have downregulated SNW1/SKIP, a splicing factor and a transcriptional co-regulator, which was found to interact with P-TEFb and synergistically affect Tat-dependent transcription elongation of HIV 1. Using the colon cancer derived cell line HCT116, we have found that both doxorubicin- and DRB-induced expression of p21 or PUMA is insensitive to SNW1 downregulation by siRNA. This suggests that transcription of stress response genes, unlike, e.g., the SNW1-sensitive mitosis-specific genes, can proceed uncoupled from regulators that normally function under physiological conditions.
- MeSH
- buněčné jádro metabolismus MeSH
- down regulace genetika MeSH
- fyziologický stres genetika MeSH
- HCT116 buňky MeSH
- HeLa buňky MeSH
- koaktivátory jaderných receptorů genetika metabolismus MeSH
- lidé MeSH
- lidské chromozomy metabolismus MeSH
- mitóza MeSH
- nádorový supresorový protein p53 metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The transcription factor p63 has important functions in tumorigenesis, epidermal differentiation and stem cell self-renewal. The TP63 gene encodes multiple protein isoforms that have different or even antagonistic roles in these processes. The balance of p63 isoforms, together with the presence or absence of the other p53 family members, p73 and p53, has a striking biological impact. There is increasing evidence that interactions between p53-family members, whether cooperative or antagonistic, are involved in various cell processes. This review summarizes the current understanding of the role of p63 in tumorigenesis, metastasis, cell migration and senescence. In particular, recent data indicate important roles in adult stem cell and cancer stem cell regulation and in the response of cancer cells to therapy.
- MeSH
- kmenové buňky metabolismus MeSH
- lidé MeSH
- myši MeSH
- nádorové kmenové buňky metabolismus MeSH
- nádorové supresorové proteiny genetika metabolismus fyziologie MeSH
- nádory metabolismus MeSH
- protein - isoformy genetika metabolismus fyziologie MeSH
- transkripční faktory genetika metabolismus fyziologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Cisplatin and doxorubicin are widely used anticancer drugs that cause DNA damage, which activates the ATM-Chk2-p53 pathway in cancer cells. This activation leads to cell cycle block or apoptosis, depending on the nature of the DNA damage. In an attempt to enhance the effects of these agents, we inhibited ATM/ATR and Chk2, which are known upstream regulators of p53. The cancer cell lines A2780 and ARN8, bearing the wild-type p53 protein, were used to study changes in p53 activation and trans-activation. Our results suggest that the G(1)-checkpoint, normally activated by DNA damage, is functionally overcome by the action of kinase inhibitors that sensitize cells to apoptosis. Both inhibitors show these effects, albeit with variable intensity in different cell lines, which is promising for other studies and theoretically for use in clinical practice.
- MeSH
- antitumorózní látky farmakologie MeSH
- apoptóza MeSH
- cisplatina farmakologie MeSH
- DNA vazebné proteiny antagonisté a inhibitory metabolismus MeSH
- down regulace MeSH
- doxorubicin farmakologie MeSH
- G0 fáze MeSH
- inhibitory proteinkinas farmakologie MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- nádorové supresorové proteiny antagonisté a inhibitory metabolismus MeSH
- nádorový supresorový protein p53 metabolismus MeSH
- poškození DNA MeSH
- protein-serin-threoninkinasy antagonisté a inhibitory metabolismus MeSH
- proteiny buněčného cyklu antagonisté a inhibitory metabolismus MeSH
- průtoková cytometrie MeSH
- signální transdukce MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The discovery of circulating nucleic acids in the 1940s opened up new possibilities for the non-invasive detection, monitoring and screening of various human disorders. Several tumour markers that enable early cancer detection or tumour behaviour prediction have been detected in the plasma of cancer patients. Maternal plasma analysis can be used to detect certain fetal abnormalities, with the quantification of cell-free nucleic acids used to screen for several pregnancy-associated disorders. Some other applications are in transplant monitoring and graft rejection assessment, and in certain medical emergencies such as trauma and burn severity stratification. Many studies have yielded promising results in this field, but the techniques have yet to be applied in routine clinical practice. Large-scale studies using similar technologies and a broad spectrum of patients are still needed to verify the results of the various studies.
- MeSH
- lidé MeSH
- nemoc MeSH
- nukleové kyseliny krev diagnostické užití MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
