Immortalization and transformation of human mammary epithelial cells by a tumor-derived Myc mutant.

The Myc transcription factor is commonly dysregulated in many human cancers, including breast carcinomas. However, the precise role of Myc in the initiation and maintenance of malignancy is unclear. In this study we compared the ability of wild-type Myc (wt Myc) or Myc phosphorylation deficient mutants (T58A, S62A or T58A/S62A) to immortalize and transform human mammary epithelial cells (HMECs). All Myc constructs promoted cellular immortalization. As previously reported in other cells, the Myc T58A mutant tempered apoptotic responses and increased Myc protein stability in HMEC cells. More importantly, we now show that HMECs overexpressing the Myc T58A mutant acquire a unique cellular phenotype characterized by cell aggregation, detachment from the substrate and growth in liquid suspension. Coincident with these changes, the cells become anchorage-independent for growth in agarose. Previous studies have shown that wt Myc can collaborate with hTERT in inducing HMEC anchorage-independent growth. We have verified this observation and further shown that Myc T58A was a stronger facilitator of such co-transformation. Thus, our findings indicate that differences in Myc protein phosphorylation modulate its biological activity in human breast epithelial cells and specifically that the T58A mutation can facilitate both cellular immortalization and transformation. Finally, we used the isogenic cell lines generated in this study to identify a subset of genes whose expression is greatly altered during the transition from the immortal to the anchorage-independent states.

Positive STAT5 Protein and Locus Amplification Status Predicts Recurrence after Radical Prostatectomy to Assist Clinical Precision Management of Prostate Cancer.

BACKGROUND: A significant fraction of prostate cancer patients experience post-radical prostatectomy (RP) biochemical recurrence (BCR). New predictive markers are needed for optimizing postoperative prostate cancer management. STAT5 is an oncogene in prostate cancer that undergoes amplification in 30% of prostate cancers during progression. METHODS: We evaluated the significance of a positive status for nuclear STAT5 protein expression versus STAT5 locus amplification versus combined positive status for both in predicting BCR after RP in 300 patients. RESULTS: Combined positive STAT5 status was associated with a 45% disadvantage in BCR in Kaplan-Meier survival analysis in all Gleason grade patients. Patients with Gleason grade group (GG) 2 and 3 prostate cancers and combined positive status for STAT5 had a more pronounced disadvantage of 55% to 60% at 7 years after RP in univariate analysis. In multivariate analysis, including the Cancer of the Prostate Risk Assessment Postsurgical nomogram (CAPRA-S) variables, combined positive STAT5 status was independently associated with a shorter BCR-free survival in all Gleason GG patients (HR, 2.34; P = 0.014) and in intermediate Gleason GG 2 or 3 patients (HR, 3.62; P = 0.021). The combined positive STAT5 status improved the predictive value of the CAPRA-S nomogram in both ROC-AUC analysis and in decision curve analysis for BCR. CONCLUSIONS: Combined positive status for STAT5 was independently associated with shorter disease-free survival in univariate analysis and was an independent predictor for BCR in multivariate analysis using the CAPRA-S variables in prostate cancer. IMPACT: Our results highlight potential for a novel precision medicine concept based on a pivotal role of STAT5 status in improving selection of prostate cancer patients who are candidates for early adjuvant interventions to reduce the risk of recurrence.

Expression of BRCC3, a novel cell cycle regulated molecule, is associated with increased phospho-ERK and cell proliferation.

Raf-1 protein serine/threonine kinase plays an important role in ERK signal transduction pathway of cell survival and proliferation. Raf-induced transcriptional changes are dependent on phosphorylation/activation of ERK. However, regulation of phospho-ERK (p-ERK) via Raf transcriptome is as yet unknown. We report the initial characterization of BRCC3, a novel gene discovered previously by mRNA expression profiling in MDA-MB 231 human breast cancer cells treated with Raf antisense oligonucleotide. BRCC3 is localized at human chromosome 5q12.1. BRCC3 open reading frame consists of 529 amino acids, coding for an approximate 60-kDa predominantly membrane-associated protein. Expression levels of BRCC3 mRNA and protein are high during G2/M phase of the cell cycle in breast cancer cells. Treatment of MDA-MB 231 cells with Raf-1 siRNA resulted in decreased expression of Raf-1, BRCC3 and p-ERK, but not B-Raf. Transient or stable expression of the epitope-tagged BRCC3 cDNA was associated with increased p-ERK in three different cell lines. Consistently, BRCC3 siRNA treatment of MDA-MB 231 cells caused decreased expression of BRCC3 and p-ERK. Furthermore, exogenous BRCC3 expression was associated with a delay in etoposide-induced cell death and an increase in cell proliferation. These findings demonstrate that BRCC3 is a novel effector of Raf-1, and implicate a role of BRCC3 in modulation of p-ERK, cell survival and proliferation.

Glutathione S-transferase pi amplification is associated with cisplatin resistance in head and neck squamous cell carcinoma cell lines and primary tumors.

PURPOSE: The purpose is to evaluate the association of glutathione S-transferase pi (GST-pi) amplification and cisplatin resistance in head and neck cancer. EXPERIMENTAL DESIGN: An analysis of chromosomal abnormalities in 10 head and neck cancer cell lines by comparative genomic hybridization was performed. GST-pi amplification and expression were evaluated in head and neck cell lines and paraffin-embedded tissue by fluorescence in situ hybridization (FISH) and immunohistochemistry. RESULTS: Changes in the DNA copy number were seen in all 10 cell lines by comparative genomic hybridization. The most frequent chromosomal alterations were: gain at 3q; loss at 3p; gain at 8q; loss of 18q; gain at 20q; loss at 8p; and gain of 11q11-q13. Using FISH, 9 of 10 cell lines showed increased GST-pi copy number. GST-pi amplification was detected in 7 of 10 cell lines. Five were relatively cisplatin resistant, and 2 were relatively cisplatin sensitive (mean IC(50), 11.2 and 2.75 microM). Two relatively cisplatin-sensitive cell lines showed GST-pi gain and another relatively cisplatin-sensitive cell line had predominantly two copies of the gene. In 10 tumor specimens, 4 had two copies of GST-pi. All 4 had a complete response to neoadjuvant chemotherapy, 3 of whom are alive >50 months from treatment compared with 2 patients showing GST-pi amplification. Neither responded to chemotherapy, and both died of disease <9 months from diagnosis. CONCLUSIONS: Using FISH, GST-pi amplification is a common event in head and neck squamous cell carcinoma and may be associated with cisplatin resistance and poor clinical outcomes in head and neck cancer patients treated with cisplatin-based therapy.

MicroRNA analysis of breast ductal fluid in breast cancer patients.

Recent studies suggest that microRNAs show promise as excellent biomarkers for breast cancer; however there is still a high degree of variability between studies making the findings difficult to interpret. In addition to blood, ductal lavage (DL) and nipple aspirate fluids represent an excellent opportunity for biomarker detection because they can be obtained in a less invasive manner than biopsies and circumvent the limitations of evaluating blood biomarkers with regards to tissue of origin specificity. In this study, we have investigated for the first time, through a real-time PCR array, the expression of 742 miRNAs in the ductal lavage fluid collected from 22 women with unilateral breast tumors. We identified 17 differentially expressed miRNAs between tumor and paired normal samples from patients with ductal breast carcinoma. Most of these miRNAs have various roles in breast cancer tumorigenesis, invasion and metastasis, therapeutic response, or are associated with several clinical and pathological characteristics of breast tumors. Moreover, some miRNAs were also detected in other biological fluids of breast cancer patients such as serum (miR-23b, -133b, -181a, 338-3p, -625), plasma (miR-200a), and breast milk (miR-181a). A systems biology analysis of these differentially expressed miRNAs points out possible pathways and cellular processes previously described as having an important role in breast cancer such as Wnt, ErbB, MAPK, TGF-ß, mTOR, PI3K-Akt, p53 signaling pathways. We also observed a difference in the miRNA expression with respect to the histological type of the tumors. In conclusion, our findings suggest that miRNA analysis of breast ductal fluid is feasible and potentially very useful for the detection of breast cancer.

Metabolomic profiling of breast tumors using ductal fluid.

Identification of new biomarkers for breast cancer remains critical in order to enhance early detection of the disease and improve its prognosis. Towards this end, we performed an untargeted metabolomic analysis of breast ductal fluid using an ultra-performance liquid chromatography coupled with a quadrupole time-of-light (UPLC-QTOF) mass spectrometer. We investigated the metabolomic profiles of breast tumors using ductal fluid samples collected by ductal lavage (DL). We studied fluid from both the affected breasts and the unaffected contralateral breasts (as controls) from 43 women with confirmed unilateral breast cancer. Using this approach, we identified 1560 ions in the positive mode and 538 ions in the negative mode after preprocessing of the UPLC­QTOF data. Paired t-tests applied on these data matrices identified 209 ions (positive and negative modes combined) with significant change in intensity level between affected and unaffected control breasts (adjusted p-values <0.05). Among these, 83 ions (39.7%) showed a fold change (FC) >1.2 and 66 ions (31.6%) were identified with putative compound names. The metabolites that we identified included endogenous metabolites such as amino acid derivatives (N-Acetyl-DL-tryptophan) or products of lipid metabolism such as N-linoleoyl taurine, trans-2-dodecenoylcarnitine, lysophosphatidylcholine LysoPC(18:2(9Z,12Z)), glycerophospholipids PG(18:0/0:0), and phosphatidylserine PS(20:4(5Z,8Z,11Z,14Z). Generalized LASSO regression further selected 21 metabolites when race, menopausal status, smoking, grade and TNM stage were adjusted for. A predictive conditional logistic regression model, using the LASSO selected 21 ions, provided diagnostic accuracy with the area under the curve of 0.956 (sensitivity/specificity of 0.907/0.884). This is the first study that shows the feasibility of conducting a comprehensive metabolomic profiling of breast tumors using breast ductal fluid to detect changes in the cellular microenvironment of the tumors and shows the potential for this approach to be used to improve detection of breast cancer.

Lack of DNA copy number alterations revealed with comparative genomic hybridization in fibroadenomas of the breast.

There are very few studies reporting DNA copy number changes in fibroadenomas of the breast. Using comparative genomic hybridization, we analyzed 20 paraffin-embedded samples of fibroadenomas of the breast from patients with no familial or previous history of breast cancer. No alterations in the DNA copy number were observed in any of the tumors analyzed, regardless of the chromosomal alterations observed using conventional cytogenetic analysis. We discuss our results and compare them to other reports on fibroadenomas.

Evaluation of adult papillary thyroid carcinomas by comparative genomic hybridization and microsatellite instability analysis.

To clarify the mechanism of tumorigenesis in papillary thyroid carcinoma (PTC) and ascertain whether genomic changes correlate with histologic features, we conducted a comprehensive molecular evaluation of PTC using comparative genomic hybridization (CGH) and microsatellite instability (MSI) analysis in a set of 17 histologically well-characterized PTC specimens. To our knowledge, this is the first study that evaluates chromosomal and nucleotide instability in the same PTC tumor specimens. Four of 15 samples (27%) had aberrations detected by CGH. All four had a partial or complete gain of chromosome 20, and 3 of 4 had a partial or complete loss of chromosome 13. No MSI was detected in any of the PTC samples (n=16), and all samples examined by immunohistochemistry (n=9) expressed the DNA repair enzymes hmlh1 and hmsh2. All PTC samples with abnormal CGH had vascular invasion or invasion of the thyroid capsule, and there was a significant correlation between the presence of chromosomal aberrations and capsular/vascular invasion (P=0.026). We conclude that although chromosomal and microsatellite instability are uncommon in PTC, tumors with chromosomal aberrations are more likely to be associated with invasion.

Genetic and epigenetic alterations in sentinel lymph nodes metastatic lesions compared to their corresponding primary breast tumors.

The accumulation of genetic and epigenetic changes plays a pivotal role in tumor development and progression. In this study, we investigated these changes using comparative genomic hybridization and bisulfite polymerase chain reaction analysis for CpG island hypermethylation of the following genes: TP16, THBS2, E-Cadherin (ECAD), RARbeta2, MINT1, MINT2, and MINT31 in six paired primary breast tumors and their matched sentinel lymph nodes (SLN). The most frequent chromosomal alterations observed were the following: losses of 6q13 approximately q23 and 13q13 approximately q32 and gains of 9q31 approximately qter, 11p15 approximately q21, 12q23 approximately qter, and 20q12 approximately qter. Gain of 6p21 approximately pter was observed in the SLN but in none of the primary tumors. Overall, 71% (30/42) of the methylation measurements were identical between the primary tumors and the SLN. Of the six cases, two showed no differences between the primary tumors and SLN, one tumor with 4 of 7 genes hypermethylated in the primary tumor showed loss of all four hypermethylation events in the SLN, and the remaining three tumors showed loss of one methylation event and simultaneous gain of one to two methylation changes in the SLN. This is the first study reporting genetic and epigenetic alterations in breast sentinel lymph nodes compared to their corresponding primary tumors. Characterization of such alterations may lead to identification of initial events associated with the metastatic dissemination process.

Pluripotent stem cells derived from adult human testes.

Recent reports have demonstrated that adult tissue cells can be induced to pluripotency, the iPS cells, mostly with the addition of genes delivered using viruses. Also, several publications both in mouse and in human have demonstrated that spermatogonial stem cells (SSCs) from testes can convert back to embryonic stem (ES)-like cells without the addition of genes. Furthermore, these pluripotent ES-like cells can differentiate into all three germ layers and organ lineages. Thus, SSCs have great potential for cell-based, autologous organ regeneration therapy for various diseases. We obtained testes from organ donors and using 1 g pieces of tissue (biopsy size) we demonstrate that testis germ cells (putative SSCs and/or their progenitors) reprogram to pluripotency when removed from their stem cell niche and when appropriate growth factors and reagents in embryonic stem cell medium are added. In addition, our method of obtaining pluripotent ES-like cells from germ cells is simpler than the described methods and may be more suitable if this procedure is developed for the clinic to obtain pluripotent cells to cure disease.

Amplification of the BP1 homeobox gene in breast cancer.

The homeobox gene BP1 is expressed in over 80% of breast cancers and is associated with tumor progression and invasion. However, the mechanism of BP1 activation in these tumors remains unknown. Therefore our aim in this study is to assess the amplification status of the BP1 gene in breast cancer and to determine whether BP1 protein expression is caused by gene amplification in these tumors. BP1 amplification and expression were assessed in 36 samples. Twenty primary breast tumors (PBT) and 14 sentinel lymph node (SLN) metastases were analyzed using fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC), respectively. Because of the close proximity of BP1 and HER2/NEU genes on 17q, correlation between their amplification/expression was also investigated. Increased BP1 copy number was observed in 33% of the cases, with a frequency of 36% and 29% in the PBT and SLN metastasis, respectively. BP1 protein was expressed in 91% of the samples: in all of the PBT with increased BP1 copy number and 65% of PBT with normal copy number. HER2/NEU amplification was detected in 22% of the cases. Concordance between BP1 and HER2/NEU copy numbers was found in 68% of the PBT and 90% of the SLN metastasis. In conclusion, we demonstrated that the BP1 homeobox gene is amplified in breast cancer, both in PBT and SLN metastasis, with a significant correlation with HER2/NEU amplification. Considering that BP1 expression was observed in cases with both increased and normal BP1 copy number, we conclude that other mechanisms in addition to gene amplification play a role in BP1 protein expression.

Neuroblastoma in southern Brazil: an 11-year study.

The authors report on the incidence and clinical characteristics of neuroblastoma in southern Brazil. The aims of the study were to evaluate the age at diagnosis, tumor stage, MYCN status, and tumor histopathology, and to relate these factors to survival. All patients with neuroblastoma, 15 years old or younger (n = 125), admitted to the three major pediatric oncology hospitals in the state of Parana over a period of 11 years (between January 1990 and December 2000), were included in the analysis. All patients were followed for at least 5 years. In addition, a FISH evaluation for MYCN status was conducted in a subset of 34 tumors. Overall survival for tumor stages 1, 2, 3, and 4 was 100%, 72%, 59%, and 17%, respectively. Sixty-two percent (77/125) of all patients were older than 2 years; these represented 71% (57/80) of the patients with stage 4 disease. Children who presented with an unfavorable histopathology had a significantly worse prognosis (20% survival) than children with a favorable histopathology (67% survival). MYCN amplification was detected most commonly in stages 3 and 4 tumors (13/16). These data showed a delayed diagnosis of neuroblastoma in children in southern Brazil, and consequently survival was considerably lower in these patients.

Detection of LOH and mitochondrial DNA alterations in ductal lavage and nipple aspirate fluids from hngh-risk patients.

We describe a method for the isolation of free DNA from ductal lavage (DL) and nipple aspirate fluid (NAF), and its evaluation for the presence of LOH at the BRCA1 and FHIT genes and for mitochondrial DNA (mtDNA) mutations at the D310 marker, to improve early detection of breast cancer. We evaluated 26 DL and six NAF samples from 14 women of known BRCA1 status, who have no clinical evidence of breast tumors: nine mutation carriers and five non-carriers. LOH studies at the BRCA1 locus were possible in 19/26 DL samples, and at the FHIT locus in 16/26 samples. In 4/9 mutation carriers we found LOH at the BRCA1 allele, and in two of these we also found LOH at the FHIT allele. In one of the mutation carriers with BRCA1 LOH, invasive breast cancer was subsequently detected, and the tumor showed the same LOH as the DL. In one of the true negatives, BRCA1 and FHIT LOH were detected. The mitochondrial studies were possible in all 26 DL samples and a somatic mutation was found in 3/9 carriers, two of whom also had LOH at the BRCA1 locus, and in none of the non-carriers. mtDNA mutation evaluation was possible in 4/6 NAF samples. The NAF and DL results were concordant. One NAF sample from a BRCA1 patient showed a mtDNA mutation. Our data demonstrates the feasibility of performing molecular studies using the free DNA present in the ductal fluid, while the intact cells can be used for cytologic studies.