Reduced expression of ΔΝp63α in cervical squamous cell carcinoma

Dysregulation of delta Np63 alpha in squamous cell carcinoma and its therapeutic targeting

The gene p63 has two isoforms -a full length transactivated isoform (TA) p63 and an amino-terminally truncated isoform, ∆Np63. DeltaNp63 alpha (∆Np63α) is the predominant splice variant of the isoform, ∆Np63 and is expressed in the basal layer of stratified epithelia. ∆Np63α that is normally essential for the epithelial lineage maintenance may be dysregulated in squamous cell carcinomas (SCCs). The pro-tumorigenic or antitumorigenic role of ∆Np63 is a highly contentious arena. ∆Np63α may act as a double-edged sword. It may either promote tumor progression, epithelial-mesenchymal transition, migration, chemoresistance, and immune-inflammatory responses, or inhibit the aforementioned phenomena depending upon cell type and tumor microenvironment. Several signaling pathways, transforming growth factor-β, Wnt and Notch, as well as epigenetic alterations involving microRNAs, and long noncoding RNAs are regulated by ∆Np63α. This review has attempted to provide an in-depth insight into the role of ∆Np63α in the development of SCCs during different stages of tumor formation and how it may be targeted for therapeutic implications.

HIV-Associated Cancer Biomarkers: A Requirement for Early Diagnosis

Globally, HIV/AIDS and cancer are increasingly public health problems and continue to exist as comorbidities. The sub-Saharan African region has the largest number of HIV infections. Malignancies previously associated with HIV/AIDS, also known as the AIDS-defining cancers (ADCs) have been documented to decrease, while the non-AIDS defining cancer (NADCs) are on the rise. On the other hand, cancer is a highly heterogeneous disease and precision oncology as the most effective cancer therapy is gaining attraction. Among HIV-infected individuals, the increased risk for developing cancer is due to the immune system of the patient being suppressed, frequent coinfection with oncogenic viruses and an increase in risky behavior such as poor lifestyle. The core of personalised medicine for cancer depends on the discovery and the development of biomarkers. Biomarkers are specific and highly sensitive markers that reveal information that aid in leading to the diagnosis, prognosis and therapy of the disease. This review focuses mainly on the risk assessment, diagnostic, prognostic and therapeutic role of various cancer biomarkers in HIV-positive patients. A careful selection of sensitive and specific HIV-associated cancer biomarkers is required to identify patients at most risk of tumour development, thus improving the diagnosis and prognosis of the disease.

lncRNA PART1 and MIR17HG as ΔNp63α direct targets regulate tumor progression of cervical squamous cell carcinoma

Cervical cancer (CC) remains one of the leading causes of mortality of female cancers worldwide, with more than 90% being cervical squamous cell carcinoma (CSCC). ΔNp63α is the predominant isoform expressed in cervical epithelial tissues and exerts its antitumor function in CSCC. In this study, we have identified 39 long noncoding RNAs as ΔNp63α targets in CSCC through RNA sequencing and chromatin immunoprecipitation sequencing, in which we further confirmed and focused on the two tumor‐related long noncoding RNAs, PART1 (lncPART1) and MIR17HG (lncMIR17HG). Experiments from stable overexpression/knockdown cell lines revealed that lncPART1 and lncMIR17HG regulated cell proliferation, migration, and invasion. In vivo experiments further showed that lncPART1 suppresses tumor growth in CSCC‐derived tumors. Examinations of clinical tissues indicated that the expression of lncPART1 was positively correlated with ΔNp63α expression, while lncMIR17HG was negatively correlated with ΔNp63α expression, suggesting that ΔNp63α plays a central role via regulating its direct targets in the progression of CSCC. These findings provide novel insights in targeted therapy of cervical cancers.

Synergetic Effects of Intronic Mature miR-944 and ΔNp63 Isoforms on Tumorigenesis in a Cervical Cancer Cell Line

miR-944 is located in an intron of the tumor protein p63 gene (TP63). miR-944 expression levels in cervical cancer tissues are significantly higher than in normal tissues and are associated with tumor size, International Federation of Gynecology and Obstetrics (FIGO) stage, lymph node metastasis, and survival. However, associations of miR-944 with its host gene, TP63, which encodes TAp63 and ΔNp63, in cervical cancer have not been fully investigated. A positive correlation between miR-944 and ΔNp63 mRNA expression was identified in cervical cancer tissues. Furthermore, when the expression of miR-944 and ΔNp63 was simultaneously inhibited, cell proliferation-, differentiation- epithelial-mesenchymal transition (EMT)-, transcription-, and virus-associated gene clusters were shown to be significantly more active according to functional annotation analysis. Cell viability and migration were more reduced upon simultaneous inhibition with anti-miR-944 or ΔNp63 siRNA than with inhibition with anti-miR-944 or ΔNp63 siRNA alone, or scramble. In addition, Western blot analysis showed that the simultaneous inhibition of miR-944 and ΔNp63 reduced EMT by increasing the expression of epithelial markers such as claudin and by decreasing mesenchymal markers such as N-cadherin and vimentin. Slug, an EMT transcription factor, was also decreased by the simultaneous inhibition of miR-944 and ΔNp63. Thus, associations between miR-944 and ΔNp63 in cervical cancer could help to elucidate the function of this intronic microRNA and its role in carcinogenesis.

p63 Expression and its Relation to Epithelial Cells Proliferation in Dentigerous Cyst, Odontogenic Keratocyst, and Ameloblastoma

The current controversy about the classification of odontogenic keratocyst reflects the shortage in the understanding of the odontogenic cysts and tumors. The aim of the present study was to investigate p63 immunoexpression and its relation to the proliferation of the epithelial lining in dentigerous cyst (DC), odontogenic keratocyst (OKC), and follicular type of ameloblastoma (AB). The study involved 36 samples, which are DC (n = 12), OKC (n = 9), and AB (n = 15). p63 protein expression was evaluated by immunohistochemistry. The results on Ki-67 expression were obtained from our previous studies and correlated with p63 expressions. p63 was expressed differently in the studied lesions with various distribution in different study samples. Statistical analysis using Kruskal-Wallis test showed a significant difference in the expression of p63 protein among DC, OKC, and AB (p = 0.048). Subsequently, Mann-Whitney U test revealed the expression of p63 protein was significantly higher in OKC than DC (p = 0.018). Interestingly, Spearman's correlation analysis showed a positive correlation between the expression of p63 and Ki-67 in the odontogenic epithelium of DC (σ = 0.757, P = 0.004) and OKC (σ = 0.741, P = 0.022). While no such a positive correlation was found between the two studied markers in AB group (σ = 0.006, P = 0.983). In conclusion, the present results indicated various expression and correlation of p63 with the proliferation of odontogenic epithelial cells in DC, OKC, and AB. This diversity could reflect a different role and pathways of ΔNp63 in odontogenic tumor than that in odontogenic cyst. These together will help in better understanding the pathogenesis and biological behavior of odontogenic cysts and tumors.

[Expressions of ΔNp63α, DPC4/Smad4 and P21 in cervical squamous cell carcinoma an their clinical significance]

OBJECTIVE

To investigate the expressions of ΔNp63α, DPC4/Smad4 and P21 in cervical squamous cell carcinomas and explore their implications in tumorigenesis, progression and prognosis of the malignancy.

METHODS

The expressions of ΔNp63α, DPC4/Smad4 and P21 were examined with immunohistochemistry in 100 specimens of cervical squamous cell carcinoma, 40 specimens of cervical intraepithelial neoplasia (CIN) and 40 specimens of normal cervical tissues to explore their associations with the occurrence, progression and prognosis of cervical squamous cell carcinoma.

RESULTS

The expressions of ΔNp63α and DPC4/Smad4 decreased and P21 expression increased significantly in the order of normal cervical tissue, CIN and cervical squamous cell carcinoma (P < 0.01), and their expressions were associated with the differentiation, clinical stages and lymph node metastasis of cervical squamous cell carcinoma (P < 0.01). The expression of ΔNp63α was positively correlated with the expression of DPC4/Smad4 (r=0.581, P < 0.05), and they were both negatively correlated with P21 expression (r=-0.449 and -0.254, respectively; P < 0.05). Kaplan-Meier survival analysis showed that patients with cervical squamous cell carcinoma positive for ΔNp63α and DPC4/Smad4 had a significantly higher 5-year survival rate than those negative for ΔNp63α and DPC4/Smad4 (P < 0.001); the patients positive for P21 had a significantly lower 5-year survival rate than the P21-negative patients (P < 0.005).

CONCLUSIONS

The expressions of ΔNp63α, DPC4/Smad4 and P21are related with the differentiation, invasion, lymph node metastasis, pTNM stage and prognosis of in cervical squamous cell carcinomas, suggesting their value as potential markers for prognostic evaluation of patients with cervical squamous cell carcinoma.

LncRNA expression profile of ΔNp63α in cervical squamous cancers and its suppressive effects on LIF expression

We aim to determine the lncRNA targets of ΔNp63α in cervical cancer and molecular programs in cancerous differentiation. Different profiles of the lncRNAs were assayed and validated in overexpressing p63 SiHa cells (SiHa/ΔNp63α) and the control cell lines (SiHa/pCon). ENST00000422259, ENST00000447565 (Lnc-LIF-AS) and ENST00000469965, together with their related antisense mRNA DPYD (dihydropyrimidine dehydrogenase, a pyrimidine catabolic pathway gene), LIF (leukemia inhibitor factor) and FLNC (filamin C) were all notably differentially expressed in both ΔNp63α overexpression cells and knockdown cells. Here, we illustrated that ΔNp63α can inhibit the levels of LIF mRNA by direct transcription regulation and decrease LIF mRNA stability by suppressing the expression of Lnc-LIF-AS. An inverse interaction of LIF and ΔNp63α expression was as well validated in clinical samples of cervical cancer, and high level of LIF in cervical cancers was related with poor patient survival. The decrease of ΔNp63α also attenuated the differentiation of cervical cancerous cells. Suggesting that ΔNp63α may be form a complex network in regulation cervical cancerous differentiation.

The E6-TAp63β-Dicer feedback loop involves in miR-375 downregulation and epithelial-to-mesenchymal transition in HR-HPV+ cervical cancer cells

MiR-375 has been recognized as an important tumor suppressor and is usually downregulated in cervical cancer. However, how it is downregulated in cervical cancer is not clear. By using cancerous and normal cervical tissues, we observed that miR-375 and Dicer are both downregulated and were positively correlated. Overexpression of miR-375 resulted in decreased viral E6 and increased Dicer expression in both Hela and SiHa cells. Previous studies suggest that E6 can induce an accelerated degradation of TAp63β, while TAp63 can bind to and transactivate the Dicer promoter, exerting a direct regulation on transcription of Dicer. In this study, we found that miR-375 overexpression restored TAp63β expression. TAp63β overexpression significantly enhanced transcription and translation of Dicer, which further led to increased mature miR-375 levels. Therefore, we infer that there is an E6-TAp63β-Dicer feedback loop involved in miR-375 dysregulation in cervical cancer. Besides, we observed that enforced TAp63β expression significantly reduced the mesenchymal markers including N-cadherin, Vimentin, Snail, and Slug but increased the epithelial marker E-cadherin in both Hela and SiHa cells. The wound healing assay also confirmed that TAp63β overexpression significantly suppressed cervical cancer cell migration potential. These results suggest that TAp63β can inhibit epithelial-to-mesenchymal transition (EMT) of cervical cancer cells.

ΔNp63α attenuates tumor aggressiveness by suppressing miR-205/ZEB1-mediated epithelial-mesenchymal transition in cervical squamous cell carcinoma

Cervical cancer is one of the most common female cancers worldwide. Although the therapeutic outcomes of patients with early-stage cervical cancer have been significantly improved in the past decades, tumor metastasis and recurrence remain the major causes of cervical cancer-related deaths. In cervical squamous cell carcinoma (SCC), the aberrant activation of epithelial-mesenchymal transition (EMT), a crucial process in invasion and metastasis of epithelial cancer, could promote lymph nodal metastasis and recurrence, and predicts poor prognosis. In this study, we show that the expression levels of EMT markers, β-catenin and Vimentin, are associated with the p63 isoform ΔNp63α in SCC by using immunohistochemistry staining and analysis. Compared to the control SiHa cells (SiHa-NC), the expression of E-cadherin and β-catenin are upregulated, while Vimentin and ZEB1 are downregulated in the constructed SiHa cell line with stable ΔNp63α overexpression (SiHa-ΔNp63α). Besides, the migration and invasion abilities are also suppressed in SiHa-ΔNp63α cells with a typical epithelial morphology with cobblestone-like shape, suggesting that ΔNp63α is a vital EMT repressor in SCC cells. In addition, the involvement of miR-205/ZEB1 axis in the inhibition effect of ΔNp63α on EMT program is revealed by a miRNA array and confirmed by the subsequent transfection of the miR-205 mimic and antagomir. Moreover, SCC patients with low ΔNp63α expression and high EMT level show more frequent metastasis and recurrence as well as reduced overall survival. Therefore, EMT program and its vital repressor ΔNp63α could be used as biomarkers for tumor metastasis and recurrence in cervical cancer.

Biomarkers of HIV-associated Cancer

Cancer biomarkers have provided great opportunities for improving the management of cancer patients by enhancing the efficiency of early detection, diagnosis, and efficacy of treatment. Every cell type has a unique molecular signature, referred to as biomarkers, which are identifiable characteristics such as levels or activities of a myriad of genes, proteins, or other molecular features. Biomarkers can facilitate the molecular definition of cancer, provide information about the course of cancer, and predict response to chemotherapy. They offer the hope of early detection as well as tracking disease progression and recurrence. Current progress in the characterization of molecular genetics of HIV-associated cancers may form the basis for improved patient stratification and future targeted or individualized therapies. Biomarker use for cancer staging and personalization of therapy at the time of diagnosis could improve patient care. This review focuses on the relevance of biomarkers in the most common HIV-associated malignancies, namely, Kaposi sarcoma, non-Hodgkin’s lymphoma, and invasive cervical cancer.