Sarit Aviel-Ronen

Human and porcine early kidney precursors as a new source for transplantation

Kidney transplantation has been one of the major medical advances of the past 30 years. However, tissue availability remains a major obstacle. This can potentially be overcome by the use of undifferentiated or partially developed kidney precursor cells derived from early embryos and fetal tissue. Here, transplantation in mice reveals the earliest gestational time point at which kidney precursor cells, of both human and pig origin, differentiate into functional nephrons and not into other, non-renal professional cell types. Moreover, successful organogenesis is achieved when using the early kidney precursors, but not later-gestation kidneys. The formed, miniature kidneys are functional as evidenced by the dilute urine they produce. In addition, decreased immunogenicity of the transplants of early human and pig kidney precursors compared with adult kidney transplants is demonstrated in vivo. Our data pinpoint a window of human and pig kidney organogenesis that may be optimal for transplantation in humans.

Class III β-Tubulin Expression and Benefit from Adjuvant Cisplatin/Vinorelbine Chemotherapy in Operable Non–Small Cell Lung Cancer: Analysis of NCIC JBR.10

Purpose: High class III β-tubulin (bTubIII) expression in advanced non–small cell lung cancer is known to correlate with reduced response rates and inferior survival with anti-microtubule agents. JBR.10 showed a 12% and 15% improvement in 5-year recurrence-free survival (RFS) and overall survival (OS), respectively, with the addition of cisplatin and vinorelbine following resection of stage IB-II non–small cell lung cancer. We sought to determine the effect of bTubIII on patient outcome and benefit from adjuvant chemotherapy in the JBR.10 trial. Experimental Design: We did a semiquantitative immunohistochemical assay for bTubIII on primary tumor tissue available from 265 of the 482 patients in JBR.10. Tumors were classified as bTubIII “low” or “high” using a validated method. We examined the prognostic effect of bTubIII in patients treated with or without chemotherapy and the survival benefit from chemotherapy in low versus high bTubIII subgroups. Results: High bTubIII expression was associated with poorer RFS and OS in patients treated with surgery alone but not in patients treated with adjuvant chemotherapy. The RFS and OS benefits of adjuvant chemotherapy were greater in high versus low tubulin expressors. However, with Cox regression, the interaction between bTubIII status and chemotherapy treatment in predicting RFS or OS did not reach statistical significance. Conclusions: Chemotherapy seemed to overcome the negative prognostic effect of high bTubIII expression. Greater benefit from adjuvant chemotherapy was seen in patients with high bTubIII expression. This is contrary to what has been seen in the setting of advanced disease; possible reasons for this difference are being explored.

Genomic markers for malignant progression in pulmonary adenocarcinoma with bronchioloalveolar features

Bronchioloalveolar carcinoma (BAC), a subtype of lung adenocarcinoma (ADC) without stromal, vascular, or pleural invasion, is considered an in situ tumor with a 100% survival rate. However, the histological criteria for invasion remain controversial. BAC-like areas may accompany otherwise invasive adenocarcinoma, referred to as mixed type adenocarcinoma with BAC features (AWBF). AWBF are considered to evolve from BAC, representing a paradigm for malignant progression in ADC. However, the supporting molecular evidence remains forthcoming. Here, we have studied the genomic changes of BAC and AWBF by array comparative genomic hybridization (CGH). We used submegabase-resolution tiling set array CGH to compare the genomic profiles of 14 BAC or BAC with focal area suspicious for invasion with those of 15 AWBF. Threshold-filtering and frequency-scoring analysis found that genomic profiles of noninvasive and focally invasive BAC are indistinguishable and show fewer aberrations than tumor cells in BAC-like areas of AWBF. These aberrations occurred mainly at the subtelomeric chromosomal regions. Increased genomic alterations were noted between BAC-like and invasive areas of AWBF. We identified 113 genes that best differentiated BAC from AWBF and were considered candidate marker genes for tumor invasion and progression. Correlative gene expression analyses demonstrated a high percentage of them to be poor prognosis markers in early stage ADC. Quantitative PCR also validated the amplification and overexpression of PDCD6 and TERT on chromosome 5p and the prognostic significance of PDCD6 in early stage ADC patients. We identified candidate genes that may be responsible for and are potential markers for malignant progression in AWBF.

Differential diagnosis of hepatocellular carcinoma from metastatic tumors in the liver using microRNA expression

Distinguishing hepatocellular carcinoma from metastatic tumors in the liver is of great practical importance, with significant therapeutic and prognostic implications. This differential diagnosis can be difficult because metastatic cancers in the liver, especially adenocarcinomas, may mimic the morphology and immunoexpression of hepatocellular carcinoma. Biomarkers that are specifically expressed in either hepatocellular carcinoma or metastatic adenocarcinoma can therefore be useful diagnostic tools. To find such biomarkers, we studied microRNA expression in 144 tumor samples using custom microarrays. Hsa-miR-141 and hsa-miR-200c, microRNAs that promote epithelial phenotypes, had significantly higher levels in non-hepatic epithelial tumors. In contrast, endothelial-associated hsa-miR-126 showed higher expression levels in hepatocellular carcinomas. Combinations of these microRNAs accurately identified primary hepatocellular carcinoma from metastatic adenocarcinoma in the liver. These findings were validated using quantitative real-time PCR to measure microRNA expression in additional samples. Thus, the tissue-specific expression patterns of microRNAs make them useful biomarkers for the diagnosis of liver malignancies.

Genomic Deregulation of the E2F/Rb Pathway Leads to Activation of the Oncogene EZH2 in Small Cell Lung Cancer

Small cell lung cancer (SCLC) is a highly aggressive lung neoplasm with extremely poor clinical outcomes and no approved targeted treatments. To elucidate the mechanisms responsible for driving the SCLC phenotype in hopes of revealing novel therapeutic targets, we studied copy number and methylation profiles of SCLC. We found disruption of the E2F/Rb pathway was a prominent feature deregulated in 96% of the SCLC samples investigated and was strongly associated with increased expression of EZH2, an oncogene and core member of the polycomb repressive complex 2 (PRC2). Through its catalytic role in the PRC2 complex, EZH2 normally functions to epigenetically silence genes during development, however, it aberrantly silences genes in human cancers. We provide evidence to support that EZH2 is functionally active in SCLC tumours, exerts pro-tumourigenic functions in vitro, and is associated with aberrant methylation profiles of PRC2 target genes indicative of a “stem-cell like” hypermethylator profile in SCLC tumours. Furthermore, lentiviral-mediated knockdown of EZH2 demonstrated a significant reduction in the growth of SCLC cell lines, suggesting EZH2 has a key role in driving SCLC biology. In conclusion, our data confirm the role of EZH2 as a critical oncogene in SCLC, and lend support to the prioritization of EZH2 as a potential therapeutic target in clinical disease.

The amyloid deposit in calcifying epithelial odontogenic tumor is immunoreactive for cytokeratins.

Calcifying epithelial odontogenic tumor, also known as Pindborg tumor, is a rare benign tumor with locally aggressive behavior. It is characterized by squamous epithelial cells, calcifications, and eosinophilic deposits that have been identified as amyloid. We report a case of calcifying epithelial odontogenic tumor and investigate the nature of the amyloid, using histologic, immunohistochemical, and ultrastructural studies. The amyloid was immunohistochemically negative for basement membrane components and positive for all cytokeratin stains performed (cocktail of cytokeratins 1, 5, 6, 8, 13, and 16, and cytokeratins AE1 and AE3). The amyloid stained focally in a glandular-like pattern, reminiscent of the epithelial glandlike structures of the tumor. We conclude that the amyloid is derived from filamentous degeneration of keratin filaments that originate from the tumor squamous epithelium. The keratin degeneration is part of a developmental or aging process that the tumor undergoes.

Localization of luteinizing hormone receptor protein in the human ovary

The luteinizing hormone receptor (LHR) plays a pivotal role during follicular development. Consequently, its expression pattern is of major importance for research and has clinical implications. Despite the accumulated information regarding LHR expression patterns, our understanding of its expression in the human ovary, specifically at the protein level, is incomplete. Therefore, our aim was to determine the LHR protein localization and expression pattern in the human ovary. We examined the presence of LHR by immunohistochemical staining of human ovaries and western blots of mural granulosa and cumulus cells aspirated during IVF treatments. We were not able to detect LHR protein staining in primordial or primary follicles. We observed equivocal positive staining in granulosa cells and theca cells of secondary follicles. The first appearance of a clear signal of LHR protein was observed in granulosa cells and theca cells of small antral follicles, and there was evidence of increasing LHR production as the follicles mature to the pre-ovulatory stage. After ovulation, LHR protein was ubiquitously produced in the corpus luteum. To confirm the expression pattern in granulosa cells and cumulus cells, we performed western blots and found that LHR expression was stronger in granulosa cells than in cumulus cells, with the later demonstrating low, but still significant, amounts of LHR protein. In summary, we conclude that LHR protein starts to appear on granulosa cells and theca cells of early antral follicles, and low but significant expression of LHR exists also in the cumulus cells. These results may have implications for the future design of clinical protocols and culture mediums for in vitro fertilization and especially in vitro maturation of oocytes.

FOXL2 C402G mutation detection using MALDI-TOF-MS in DNA extracted from Israeli granulosa cell tumors

OBJECTIVE To develop a rapid, sensitive and reliable method to detect FOXL2 C402G mutation in granulosa cell tumor (GCT) and to investigate the prevalence of FOXL2 mutation in granulose cell tumors among Israeli patients. METHODS We designed and optimized a matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) genotyping assay to detect FOXL2 C402G mutation in DNA isolated from formalin-fixed paraffin-embedded tissue samples. We examined 20 tumor samples obtained from Israeli patients diagnosed with granulose cell tumor. RESULTS Eighteen out of 20 samples were found to harbor FOXL2 C402G mutation. Pathological review of the two tumors harboring wild type FOXL2 (C402) concluded that they were adenocarcinomas and has been misclassified at initial diagnosis. We found that the prevalence of FOXL2 mutations among Israeli patients with GCT (100%) is similar to previous reports. CONCLUSIONS Our results indicate that the FOXL2 mutations can be reliably detected by MALDI-TOF-MS genotyping. MALDI-TOF-MS genotyping is a simple, robust and highly sensitive method to detect FOXL2 C402G mutation. Our results confirm previous studies reporting over 95% prevalence of FOXL2 mutation in GCT. Furthermore, we suggest that testing for the presence of the FOXL2 C402G mutation may improve diagnostic accuracy.

Primary Malignancies of the Heart and Pericardium

Primary malignancies of the heart and pericardium are rare. All the available data come from autopsy studies, case reports, and, in recent years, from large, specialized, single‐center studies. Nevertheless, if primary malignancy is present, it may have a devastating implication for patients. Malignancies may affect heart function, also causing left‐sided or right‐sided heart failure. In addition, they can be responsible for embolic events or arrhythmias. Today, with the widespread use of noninvasive imaging modalities, heart tumors become evident, even as an incidental finding. A multimodality imaging approach is usually required to establish the final diagnosis. Despite the increased awareness and improved diagnostic techniques, clinical manifestations of primary malignancy of the heart and pericardium are so variable that their occurrence may still come as a surprise during surgery or autopsy. No randomized clinical trials have been carried out to determine the optimal therapy for these primary malignancies. Surgery is performed for small tumors. Chemotherapy and radiation therapy can be of help. Partial resection of large neoplasms is performed to relieve mechanical effects, such as cardiac compression or hemodynamic obstruction. Most patients present with marginally resectable or technically nonresectable disease at the time of diagnosis. It seems that orthotopic cardiac transplantation with subsequent immunosuppressive therapy may represent an option for very carefully selected patients. Early diagnosis and radical exeresis are of great importance for long‐term survival of a primary cardiac malignancy. This can rarely be accomplished, and overall results are very disappointing.

Tumor Suppressor Activity of Klotho in Breast Cancer is Revealed by Structure-function Analysis

Klotho is a transmembrane protein containing two internal repeats, KL1 and KL2, both displaying significant homology to members of the β-glycosidase family. Klotho is expressed in the kidney, brain, and various endocrine tissues, but can also be cleaved and act as a circulating hormone. Klotho is an essential cofactor for binding of fibroblast growth factor 23 (FGF23) to the FGF receptor and can also inhibit the insulin-like growth factor-1 (IGF-1) pathway. Data from a wide array of malignancies indicate klotho as a tumor suppressor; however, the structure–function relationships governing its tumor suppressor activities have not been deciphered. Here, the tumor suppressor activities of the KL1 and KL2 domains were examined. Overexpression of either klotho or KL1, but not of KL2, inhibited colony formation by MCF-7 and MDA-MB-231 cells. Moreover, in vivo administration of KL1 was not only well tolerated but significantly slowed tumor formation in nude mice. Further studies indicated that KL1, but not KL2, interacted with the IGF-1R and inhibited the IGF-1 pathway. Based on computerized structural modeling, klotho constructs were generated in which critical amino acids have been mutated. Interestingly, the mutated proteins retained their tumor suppressor activity but showed reduced ability to modulate FGF23 signaling. These data indicate differential activity of the klotho domains, KL1 and KL2, in breast cancer and reveal that the tumor suppressor activities of klotho can be dissected from its physiologic activities. Implications: These findings pave the way for a rational design of safe klotho-based molecules for the treatment of breast cancer. Mol Cancer Res; 13(10); 1398–407. ©2015 AACR.