Juana M. García-Pedrero

Hey1, a Mediator of Notch Signaling, Is an Androgen Receptor Corepressor

ABSTRACT Hey1 is a member of the basic helix-loop-helix-Orange family of transcriptional repressors that mediate Notch signaling. Here we show that transcription from androgen-dependent target genes is inhibited by Hey1 and that expression of a constitutively active form of Notch is capable of repressing transactivation by the endogenous androgen receptor (AR). Our results indicate that Hey1 functions as a corepressor for AF1 in the AR, providing a mechanism for cross talk between Notch and androgen-signaling pathways. Hey1 colocalizes with AR in the epithelia of patients with benign prostatic hyperplasia, where it is found in both the cytoplasm and the nucleus. In marked contrast, we demonstrate that Hey1 is excluded from the nucleus in most human prostate cancers, raising the possibility that an abnormal Hey1 subcellular distribution may have a role in the aberrant hormonal responses observed in prostate cancer.

The SWI/SNF Chromatin Remodeling Subunit BAF57 Is a Critical Regulator of Estrogen Receptor Function in Breast Cancer Cells

Estrogen receptors (ERs) play critical roles in both normal mammary gland development and in the formation and progression of breast tumors, constituting a major therapeutic target for breast cancer treatment. We have previously described that ER transcriptional activity is potentiated by BAF57, a core subunit of the mammalian SWI/SNF chromatin remodeling complex. Here we provide evidence demonstrating an important role for BAF57 as regulator of ER functions in breast cancer cells. Different experimental manipulations leading to the abrogation of BAF57 expression and/or function severely reduced the expression of various endogenous ER target genes and blocked estrogen-stimulated proliferation in ZR-75-1 breast cancer cells. Moreover, using a structure-function analysis, we have defined the protein domains required for the functional interaction between ERα and BAF57, including a key region within the hinge of ERα that is essential for BAF57 recruitment and its function on ER-mediated transcription. Interestingly, we found that BAF57 is an ER subtype-selective modulator that specifically regulates ERα-mediated transcription. Taken together, our results suggest that targeting BAF57 could represent a new way to effectively inhibit the action of ERα.

Distinctive clinicopathological associations of amplification of the cortactin gene at 11q13 in head and neck squamous cell carcinomas.

Amplification of the 11q13 region is a prevalent genetic alteration in head and neck squamous cell carcinoma (HNSCC). We investigated the clinical significance of cortactin (CTTN) and cyclin D1 (CCND1) amplification in both malignant transformation and tumour progression. CTTN and CCND1 amplification was analysed by differential and real‐time PCR in a prospective series of laryngeal/pharyngeal carcinomas and archival premalignant tissues. CTTN mRNA and protein expression were respectively determined by real‐time RT‐PCR and immunohistochemistry, and correlated with gene status. Molecular alterations were associated with clinicopathological parameters and disease outcome. CTTN and CCND1 amplifications were respectively found in 75 (37%) and 90 (45%) tumours. Both correlated with advanced disease; however, only CTTN amplification was associated with recurrence and reduced disease‐specific survival (p = 0.0022). Strikingly, CTTN amplification differentially influenced survival depending on tumour site (p = 0.0001 larynx versus p = 0.68 pharynx) and was an independent predictor of reduced survival in the larynx (p = 0.04). CCND1 amplification was detected in early tumourigenesis and increased with the severity of dysplasia. Importantly, CTTN amplification was only found in high‐grade dysplasias that progressed to invasive carcinoma. CTTN gene status strongly correlated with mRNA and protein expression. Furthermore, CTTN overexpression correlated significantly with reduced disease‐specific survival (p = 0.018). Taken together, these data indicate that CTTN may serve as a valuable biomarker to identify patients with laryngeal tumours at high risk of recurrence and poor outcome. Copyright

Podoplanin expression in the development and progression of laryngeal squamous cell carcinomas.

BackgroundPodoplanin expression is attracting interest as a marker for cancer diagnosis and prognosis. We therefore investigated the expression pattern and clinical significance of podoplanin during the development and progression of laryngeal carcinomas.ResultsPodoplanin expression was determined by immunohistochemistry in paraffin-embedded tissue specimens from 84 patients with laryngeal premalignancies and 53 patients with laryngeal squamous cell carcinomas. We found podoplanin expression extending from the basal to the suprabasal layer of the epithelium in 37 (44%) of 84 dysplastic lesions, whereas normal epithelium showed negligible expression. Patients carrying podoplanin-positive lesions had a higher laryngeal cancer incidence than those with negative expression reaching borderline statistical significance (51% versus 30%, P = 0.071). Podoplanin expression in laryngeal carcinomas exhibited two distinct patterns. 20 (38%) cases showed diffuse expression in most tumour cells and 33 (62%) focal expression at the proliferating periphery of tumour nests. High podoplanin expression was inversely correlated with T classification (P = 0.033), disease stage (P = 0.006), and pathological grade (P = 0.04). There was a trend, although not significant, towards reduced disease-specific survival for patients with low podoplanin levels (P = 0.31) and diffuse expression pattern (P = 0.08).ConclusionsPodoplanin expression increases in the early stages of laryngeal tumourigenesis and it seems to be associated with a higher laryngeal cancer risk. Podoplanin expression in laryngeal squamous cell carcinomas, however, diminishes during tumour progression. Taken together, these data support a role for podoplanin expression in the initiation but not in the progression of laryngeal cancers.

Time trends in the prevalence of HPV in oropharyngeal squamous cell carcinomas in northern Spain (1990-2009).

Recent studies support an important role for human papillomavirus (HPV) in oropharyngeal squamous cell carcinomas (OPSCC), although the incidence varies widely depending on the geographic location and time period studied. The aim of this study was to determine the proportion of HPV in a large cohort of OPSCC in northern Spain in the years 1990–2009. Clinical records and paraffin embedded tumor specimens of 248 consecutive patients surgically treated for OPSCC (140 tonsillar and 108 base of tongue) between 1990 and 2009 were retrieved. OPSCC cases were histomorphologically evaluated, and protein expression of p16 and p53 was analyzed by immunohistochemistry. Detection of high‐risk HPV DNA was performed by GP5+/6+‐PCR and in situ hybridization (ISH). Thirty cases (12%) were positive for p16 immunostaining, of which eight (3.2% of the total series) were found positive for HPV type 16 by genotyping of GP5+6+‐PCR products. All HPV GP5+/6+‐PCR‐positive tumors were p53‐immunonegative, seven had a basaloid morphology and seven were also positive by HPV ISH. Presence of HPV correlated inversely with tobacco and alcohol consumption (p < 0.001), but not with age of onset of OPSCC. Overall survival was better in the HPV‐positive group, although not statistically significant (p = 0.175). OPSCC patients in northern Spain demonstrated a low involvement of HPV, increasing (although not significantly, p = 0.120) from 1.8% in 1990–1999 to 6.1% of cases in 2000–2009.

Regulation of the expression of death receptors and their ligands by melatonin in haematological cancer cell lines and in leukaemia cells from patients

Abstract:  Incorporation of new therapeutic agents remains as a major challenge for treatment of patients with malignant haematological disorders. Melatonin is an indolamine without relevant side effects. It has been shown previously to exhibit synergism with several chemotherapeutic drugs in Ewing sarcoma cells by potentiating the extrinsic pathway of apoptosis. It also sensitizes human glioma cells against TRAIL by increasing DR5 expression. Here, we report the induction of cell death by melatonin in several human malignant haematological cell lines through the activation of the extrinsic pathway of apoptosis. Such activation was mediated by the increase in the expression of the death receptors Fas, DR4 and DR5 and their ligands Fas L and TRAIL, with a remarkable rise in the expression of Fas and Fas L. The cytotoxic effect and the increase in Fas and Fas L were dependent on Akt activation. Results were corroborated in blasts from bone marrow and peripheral blood of acute myeloid leukaemia patients, where melatonin induced cell death and increased both Fas and Fas L expressions. We conclude that melatonin may be considered as a potential antileukaemic agent and its therapeutic use, either alone or in combination with current chemotherapeutic drugs, should be taken into consideration for further research.

Down-regulation of annexin A1 and A2 protein expression in intestinal-type sinonasal adenocarcinomas.

Annexins are a structurally related family of calcium- and phospholipid-binding proteins that have been implicated in a broad range of molecular and cellular processes. The altered expression of individual annexins has been implicated in tumor development and progression. In this study the expression of annexin A1 and annexin A2 was studied by immunohistochemistry in intestinal-type sinonasal adenocarcinoma using a study set of 57 intestinal-type sinonasal adenocarcinomas represented on an intestinal-type sinonasal adenocarcinoma tissue microarray to assess its potential role in the pathogenesis of these tumors. Our results showed that annexin A1 expression was consistently lost in 52 (91%) intestinal-type sinonasal adenocarcinomas, as compared with the normal epithelium. The expression of annexin A2 was more heterogeneous, and only 19 (33%) cases showed annexin A2 negative expression. Annexin A2 expression was correlated with the histopathological type, being lower in the mucinous type (P = .022). The loss of annexin A2 expression correlated with a reduced survival in univariate analysis (P = .004). However, the impact of annexin A2 expression on patient survival could be an indirect consequence of its association with the histopathological type, since annexin A2 expression was not found to be an independent predictor in multivariate analyses. These results suggest that annexin A1 expression is frequently and commonly lost in intestinal-type sinonasal adenocarcinoma development. Annexin A2 expression is also reduced in intestinal-type sinonasal adenocarcinoma, and this loss of expression is associated to the more aggressive histopathological types.

Annexin A1 expression in nasopharyngeal carcinoma correlates with squamous differentiation.

Background Alterations of annexin A1 (ANXA1) expression have been reported in various cancers. However, no data are available about the expression of this protein in nasopharyngeal carcinomas (NPCs). The objective of this study was to investigate the expression of ANXA1 in these tumors. Methods We examined noncancerous nasopharyngeal mucosa (4 cases) and NPC (20 cases) for ANXA1 expression using immunohistochemistry. Results All tumor tissues showed markedly reduced ANXA1 expression compared with a strong positive signal observed in the corresponding normal epithelia. We found that ANXA1 expression is associated with the histological type in NPC. Only squamous cell carcinomas presented a positive ANXA1 signal in differentiated areas whereas all poorly differentiated tumors exhibited negative staining. Conclusion Our data show for the first time that ANXA1 expression is down-regulated in NPC and that its expression seems to be related with the squamous differentiation status of these tumors.

Podoplanin expression in oral leukoplakia: Tumorigenic role

OBJECTIVES Recent studies have identified podoplanin, a mucin-type transmembrane glycoprotein, as a biomarker for oral cancer risk in patients with oral leukoplakia (OPL). The aim of this study was to investigate the potential association between podoplanin and the risk of malignant transformation of OPL with epithelial dysplasia. MATERIALS AND METHODS In this retrospective study, podoplanin immunoexpression was analyzed in 58 patients with oral leukoplakia that showed epithelial dysplasia. Lesions with podoplanin expression in the basal and suprabasal layers of oral epithelium at one area or showing suprabasal expression at two or more areas were considered as positive. Association between podoplanin expression and oral cancer development was analyzed. RESULTS Twenty-two of the 58 lesions (38%) were classified as podoplanin-positive, and the remaining 36 (62%) lesions were considered podoplanin-negative. The expression of podoplanin was correlated with the grade of dysplasia (p<0.0005), and with the risk of progression to oral cancer (p<0.0005). In multivariate survival analysis, only premalignant oral lesions displaying positive podoplanin expression showed a significantly increased risk of developing an oral squamous cell carcinoma (hazard ratio=8.738, p=0.007). CONCLUSION Podoplanin could be a valuable biomarker for risk assessment of malignant transformation in patients with OPL along with histological assessment.

Cortactin and Focal Adhesion Kinase as Predictors of Cancer Risk in Patients with Laryngeal Premalignancy

Novel markers are needed to accurately predict the risk of malignant transformation in laryngeal premalignancies. We therefore investigated the clinical significance of cortactin (CTTN) and focal adhesion kinase (FAK) during laryngeal tumorigenesis and their potential utility as cancer risk markers. CTTN and FAK protein expression and gene amplification were assessed in 82 patients with laryngeal dysplasia and correlated with clinicopathologic parameters and laryngeal cancer risk. Increased CTTN and FAK expression was found respectively in 41 (50%) and 40 (49%) of 82 laryngeal dysplasias; protein expression was maintained or further augmented in the corresponding patient-matched invasive tumors subsequently developed. CTTN and FAK/PTK2 gene amplifications were respectively detected in 10 (12%) and 26 (32%) laryngeal dysplasias. Both CTTN and FAK protein expression increased with the grade of dysplasia; however, CTTN and FAK expression but not histology correlated significantly with increased laryngeal cancer risk (P = 0.009 and P = 0.002, respectively). Patients carrying strong CTTN- or FAK-expressing dysplastic lesions experienced a significantly higher cancer incidence (P = 0.006 and P = 0.001, respectively; log-rank test). Furthermore, FAK expression was an independent predictor of laryngeal cancer development (HR = 3.706, 95% CI: 1.735–7.916; P = 0.001) and the combination of FAK and CTTN showed superior predictive value (HR = 5.042, 95% CI: 2.255–11.274; P < 0.001). Taken together, our findings support the involvement of CTTN and FAK in malignant transformation and provide original evidence for their potential clinical utility as biomarkers for the risk of developing laryngeal cancer. Cancer Prev Res; 4(8); 1333–41. ©2011 AACR.