Estrogen and ghrelin decrease cytoplasmic expression of p27<Superscript>kip1</Superscript>, a cellular marker of ageing,in the striated anal sphincter and levator muscle of ovariectomized rats

A study was carried out to investigate the effect of estrogen and/or ghrelin on the cellular marker of ageing, p27^kip1, in pelvic floor muscles of ovariectomized rats. Virgin Wistar rats (13 months old) underwent ovariectomy followed (1 month) by 42 daily intraperitoneal 17-β estradiol (10 μg/kg), ghrelin (2 μg/kg), both hormones, or placebo vehicle (n=6×4 groups). Six more age-matched animals underwent sham surgery without ovariectomy. Cytoplasmic expression of p27^kip1 in the striated urethral and anal sphincters and levator muscle was measured by Western blot analysis in all animals (n=30). p27^kip1 signal intensity significantly increased postovariectomy in all muscles compared to sham animals. In the anal sphincter and levator, signal intensity decreased to sham levels with ghrelin or estrogen and decreased further after estrogen or ghrelin and estrogen/ghrelin administration. Urethral sphincter signal intensity decreased without reaching sham levels after drug administration. Estrogen and/or ghrelin replacement reverses the ovariectomy-induced exacerbation of biochemical cellular ageing in the anal sphincter and levator muscle of middle-aged rats.     

Induction of cell cycle arrest and apoptosis in human prostate carcinoma cells by a recombinant adenovirus expressing p27(Kip1)

BACKGROUND: Adp27(Kip1), a recombinant adenovirus, was evaluated for expression of p27, a cyclin-dependent kinase inhibitor (CDKI) and tumor suppressor protein, in human prostate carcinoma cells. Effects of p27(Kip1) on cell cycle and apoptosis were analyzed. METHODS: We evaluated the effects of overexpression of p27(Kip1) in the human prostate carcinoma cell lines LNCaP, DU-145, and PC-3 in vitro and in vivo. Growth curve studies, cell cycle analysis, terminal deoxynucleotidyl transferase-mediated nick end-labeling (TUNEL), and annexin V-fluorescein isothiocyanate apoptosis analyses were conducted to determine effects of p27(Kip1) on cell cycle. CDKI activity assays and Western blots were conducted to determine presence/activities of CDKIs. RESULTS: Adp27(Kip1)-induced protein levels increased in a dose-dependent manner; p27(Kip1) protein was detected within 6 hr of infection with Adp27(Kip1) and remained stable for at least 48 hr. The activities of Cdk2, Cdk4, and Cdc2 kinases were inhibited 24 hr after infection with Adp27(Kip1). Bromodeoxyuridine incorporation demonstrated a dose-dependent decrease in S-phase cells 24 hr postinfection. TUNEL analysis revealed an induction of apoptosis (10 pfu/cell) within 48 hr of infection in all cell lines. Growth curve analyses demonstrated that Adp27(Kip1) infection inhibited proliferation of all cell lines tested and decreased cell numbers for Adp27(Kip1)-infected LNCaP and PC-3 cells by 96 hr. Cell cycle analysis of DNA content demonstrated an accumulation of cells in G0/G1-phase 24-120 hr after Adp27(Kip1)-infection. In vivo studies demonstrated a reduction in LNCaP xenograft tumor growth rates in mice injected with Adp27(Kip1). CONCLUSION: Exogenous p27(Kip1) overexpression results in cell cycle regulation in the human prostate carcinoma cell lines tested, representing the first use of this vector on prostate cancer cell lines in vitro and in vivo. Moreover, p27(Kip1) expression is associated with an increase in early apoptosis, which represents a recently discovered function for this protein. It also represents the first time this association has been observed in prostate carcinoma cell lines. This study provides support for the further development of Adp27(Kip1) as a potential therapeutic vector in the treatment of adenocarcinoma of the prostate.     

p27kip1 Expression Is Associated With Tumor Response to Preoperative Chemoradiotherapy in Rectal Cancer

BACKGROUND: Our aim was to ascertain whether or not the response to preoperative chemoradiotherapy for rectal cancer is associated with p27kip1 and p53 protein expression. METHODS: Thirty-eight patients (27 male, 11 female) with a mean age of 59 years (age range 33-87) and stage II-III rectal cancer received preoperative chemoradiotherapy (45-50.4 Gy; 5-FU 350 mg/m2/day and leucovorin 10 mg/m2/day). Thirty-one underwent low anterior resection; seven underwent abdominoperineal excision. Endoscopic tumor biopsies, performed before adjuvant therapy, were evaluated for: histologic type, tumor differentiation, mitotic index, and p27kip1 and p53 protein expression which were immunohistochemically determined. p53 expression was graded as: a) absent or present in < or =10% of tumor cells; b) present in 11-25%; c) present in 26-75%; and d) present in >75% of tumor cells. p27kip1 expression was assessed using both light microscopy (percent of stained cells x10 HPF) and cytometry with an image analysis workstation. Tumor response, ascertained with histology, was classified using a scale from 0 (no response) to 6 (complete pathologic response). RESULTS: The mitotic index for the endoscopic biopsies was low in 14 cases, moderate in 17 cases, and high in 7 cases. p53 protein expression was found in 21 (a), 3 (b), 3 (c), and 11 (d) cases. The mean percentage of cells expressing the p27kip1 protein was 34 (range 0-77.14%). A close correlation was found between cytometric and light microscopy findings for p27kip1 (r2 = 0.92, P = .0001). Tumor differentiation was good in 5 cases, poor in 2 cases, and moderate in the remaining 31 cases. While the response to adjuvant therapy was good/complete in 25 (65.78%) cases, it was absent/poor in 13 (34.21%) cases. Univariate analysis associated type of adjuvant therapy (chemoradiotherapy, P = .0428) and p27kip1 protein lower expression (P = .0148) with a poor response to adjuvant treatment. Stepwise linear regression found overexpression of p53 and p27kip1 and young age to be independent variables that were linked to a good response to adjuvant therapy. CONCLUSIONS: Lack of p27kip1 and p53 protein expression in rectal cancer is associated with a poor response to preoperative adjuvant therapy.     

Cell cycle regulation of human pancreatic cancer by tamoxifen

Background: Clinical trials have suggested a survival advantage for selected patients with metastatic pancreatic cancer treated with tamoxifen. We sought to identify the molecular mechanism by which tamoxifen inhibits human pancreatic cancer cell (HPCC) growth. Methods: HPCCs were grown in tamoxifen and growth inhibition was determined by³H-thymidine uptake and by the MTT assay; changes in cell viability were determined by cell counts. Cell cycle alterations were evaluated by FACS, and the induction of apoptosis was evaluated using the TUNEL assay. Total cellular RNA was isolated after tamoxifen treatment, and Northern blot analysis was performed for p21 ^waf1 . Results: Tamoxifen inhibited HPCC growth as measured by inhibition of³H-thymidine incorporation and by the MTT assay. However, there was no decrease in the total number of viable cells after 6 days of treatment with 10 μM of tamoxifen and no evident apoptosis, confirming the absence of a cytotoxic effect. Cell cycle analysis revealed cellular arrest in the G₀/G₁ phase, which correlated with p21 ^waf1 mRNA upregulation in response to tamoxifen treatment. Conclusions: Tamoxifen inhibits HPCC growth by inducing G₀/G₁ arrest with an associated increase in p21 ^waf1 mRNA expression. Tamoxifen is an effective inhibitor of HPCC growth in vitro and warrants further in vivo study.     

Loss of p27<Superscript>(Kip1) </Superscript>CDKI is a predictor of poor recurrence-free and cancer-specific survival in patients with renal cancer

The importance of cyclin-dependent kinase inhibitors (CDKI) in benign and malignant urological diseases is a subject of intense ongoing investigation. The goal of the current study was to analyze the expression of p27^(Kip1) CDKI in benign and malignant renal cells and assess their possible association with different clinical parameters. Expression of p27^(Kip1) was evaluated and compared in 24 normal human kidneys and in 52 renal cell carcinoma (RCC) tissue samples. Intensity of the expression was compared between the groups and association was analyzed with cancer clinical parameters. The expression of the marker was significantly higher in normal than in RCC samples (P = 0.0045). Intensity of p27^(Kip1) expression in RCC was negatively correlated with tumor size (Rho = −0.438, P = 0.0051) and associated with pathological stage and grade (P = 0.0488 and < 0.0001, respectively). The patients with symptomatic disease had significantly less marker expression than incidentally discovered tumors (P = 0.0301). Loss of p27^(Kip1) expression, pathological stage, grade and tumor size were the risk-factors for disease recurrence (P = 0.0072, 0.0011, 0.0467 and < 0.0001, respectively) and patient survival (P = 0.0021, 0.0106, 0.0151 and 0.0021, respectively). With Cox multivariate analysis loss of p27^(Kip1) expression (hazard ratio 9.3, P = 0.002) and tumor size (hazard ratio 5.9, P = 0.015) were the predictors of cancer-specific survival. Expression of p27^(Kip1) is significantly decreased in RCC as compared with normal kidney tissue. Intensity of the expression is associated with clinical parameters: tumor size, stage, grade and disease presentation. Loss of p27^(Kip1) expression is a risk-factor for disease recurrence and the strongest predictor of cancer-specific survival.     

Heterogenic Loss of the Wild-Type BRCA Allele in Human Breast Tumorigenesis

Background For individuals genetically predisposed to breast and ovarian cancer through inheritance of a mutant BRCA allele, somatic loss of heterozygosity affecting the wild-type allele is considered obligatory for cancer initiation and/or progression. However, several lines of evidence suggest that phenotypic effects may result from BRCA haploinsufficiency. Methods Archival fixed and embedded tissue specimens from women with germ line deleterious mutations in BRCA1 or BRCA2 were identified. After pathologic review, focal areas of normal breast epithelium, atypical ductal hyperplasia, ductal carcinoma-in-situ, and invasive ductal carcinoma were identified from 14 BRCA1-linked and 9 BRCA2-linked breast cancers. Ten BRCA-linked prophylactic mastectomy specimens and 12 BRCA-linked invasive ovarian carcinomas were also studied. Laser catapult microdissection was used to isolate cells from the various pathologic lesions and corresponding normal tissues. After DNA isolation, real-time polymerase chain reaction assays were used to quantitate the proportion of wild-type to mutant BRCA alleles in each tissue sample. Results Quantitative allelotyping of microdissected cells revealed a high level of heterogeneity in loss of heterozygosity within and between preinvasive lesions and invasive cancers from BRCA1 and BRCA2 heterozygotes with breast cancer. In contrast, all BRCA-associated ovarian cancers displayed complete loss of the wild-type BRCA allele. Conclusions These data suggest that loss of the wild-type BRCA allele is not required for BRCA-linked breast tumorigenesis, which would have important implications for the genetic mechanism of BRCA tumor suppression and for the clinical management of this patient population.     

Absence of the Cell Cycle Inhibitor p27Kip1 Protein Predicts Poor Outcome in Patients With Stage I-III Colorectal Cancer

Background: The p27^Kip1 protein regulates the G1 to S phase transition of cell cycle by binding to and inhibiting the cyclin E/Cdk2 complex. This study explores the prognostic significance of the absence of the p27^Kip1 protein in patients with colorectal cancer (CRC).Methods: Formalin-fixed tumor sections from 124 patients who underwent curative resection for stage I-III CRC were analyzed by immunohistochemistry using MoAb anti-p27^Kip1.Results: Detectable levels of p27^Kip1 protein were found in 86% of tumors. Median follow-up was 55 months. Actuarial 5-year disease-free survival (DFS) and overall survival (OS) were 76% and 85%, respectively, in patients with tumors with p27^Kip1 protein expression and 34% and 40%, respectively, in those whose tumors lacked p27^Kip1 protein expression (P < .001). At multivariate analysis, tumor stage (III vs. I-II) and p27^Kip1 protein status (absence vs. presence) were found to be independent prognostic factors for DFS and OS.Conclusions: Lack of p27^Kip1 protein expression in CRC is a negative prognostic marker and may therefore be useful in selecting early-stage patients more likely to benefit from adjuvant treatment.Presented at the 51st Annual Cancer Symposium of The Society of Surgical Oncology, San Diego, California, March 26–29, 1998.     

Assessing the Use of p16 Promoter Gene Methylation in Serum for Detection of Bladder Cancer

Objective: This study was undertaken to investigate whether hypermethylation in p16^INK4a gene promoter could serve as plasma biomarker of bladder cancer.Methods and Patients: We examined the p16^INK4a status using methylation-specific PCR in 86 cancer patients and 49 controls (31 healthy people and 18 patients with benign urological diseases).Results: The p16^INK4a methylation was found in 22% of the serum samples and in 26% of the bladder cancer biopsies; one of them with carcinoma in situ. The presence of hypermethylated p16^INK4a in serum seems to be a product from tumour cells because a strong statistical association was found between both matched DNA signals (p<0.0001). Using the control group, the presence of methylated p16^INK4a in the serum of individuals with suspicion of bladder cancer was found to be associated with the tumour presence (p=0.0009). Aberrant p16^INK4a methylation was also observed in one non-cancer patient, which is undergoing further assessment.Conclusions: According with our results, methylation of p16^INK4a promoter may be involved in the bladder cancer genesis and the presence of p16^INK4a methylated in serum of these patients could be useful in the cancer diagnosis with values of sensitivity, specificity and positive predictive value of 0.226, 0.950 and 0.98, respectively. These figures support the use of methylated p16^INK4a as a new class of tumour marker in bladder cancer.     

Methylation and Gene Silencing of the Ras-Related GTPase Gene in Lung and Breast Cancers

Background RRAD, a small Ras-related GTPase, is highly expressed in human skeletal muscle, lung, and heart. Although loss of expression of RRAD in breast cancer cells has been reported and it may act as an oncogene, the mechanism of silencing is unknown. Methods We examined (1) mRNA expression of RRAD in lung and breast cancer cell lines using RT-PCR and (2) methylation status of lung and breast cancers. Results Loss of RRAD expression was found in 14 of 20 (70%) NSCLC cell lines, 11 of 11 (100%) SCLC cell lines, and 8 of 10 (80%) breast cancer cell lines; expression was not affected in normal bronchial and mammary epithelial cells. Treatment of 23 expression-negative cell lines with a demethylating agent restored expression in all cases. We developed a methylation-specific assay from the analysis of bisulfite sequencing of the 5′ region of RRAD in expression-negative and positive cell lines, which resulted in good concordance between methylation and expression. Primary lung and breast cancers showed hypermethylation in 89 of 214 (42%) and 39 of 63 (62%) cases, respectively. RRAD hypermethylation correlated with smoking history and poorer prognosis in lung adenocarcinomas. Conclusions We conclude that epigenetic silencing of RRAD is a frequent event in lung and breast cancers, and analysis of it may provide novel opportunities for prognosis and therapy of these cancers.     

P27 does not predict histopathological response to radiochemotherapy in rectal cancer

BACKGROUND: Tumor response to radiochemotherapy (RCT) varies considerably, even among patients treated in accordance with the same protocol. The aim of the present study was to test the predictive value of the cell-cycle inhibitor p27kip1 with regard to neoadjuvant RCT response in rectal cancer. MATERIALS AND METHODS: P27kip1 was evaluated by immunohistochemistry in pretreatment biopsy material obtained from 42 patients with rectal cancer treated uniformly in accordance with an identical prospective neoadjuvant RCT protocol (CAO/AIO/ARO-94). Four expression patterns (staining intensity [-,+,++,+++] and the percentage of positive cells, evaluated separately for nuclei and cytoplasm) of p27kip1 were investigated for correlation with tumor response, which was assessed in the resected surgical specimen using a histopathological five-point grading system. Additionally, p27(kip1) expression was investigated for correlation with several pathological features, overall survival, and disease-free survival. RESULTS: p27kip1 expression was as follows: nuclear intensity: -: 8, +: 19, ++: 11, +++: 4 cases, median percentage of positive cells: 18.75%; cytoplasmic intensity: -: 0, +: 25, ++: 12, +++: 3 cases, median percentage of positive cells: 70%. Histopathological tumor regression was acceptable in 30 patients (3 complete; 27 good) and inadequate in 12 patients (7 moderate; 5 minimal). No tumor failed to show some regression. No significant correlation was found between any of the p27kip1 expression patterns and RCT response, tumor differentiation (low grade versus high grade), cT- and ypT-category, UICC stage, overall survival, and disease-free survival. CONCLUSIONS: p27kip1 cannot aid the individualization of multimodal treatment strategies in rectal cancer, nor can it serve as a predictor of survival.     

Radiation induces<Emphasis Type="Italic"> p53</Emphasis>-dependent cell apoptosis in bladder cancer cells with wild-type-<Emphasis Type="Italic">p53</Emphasis> but not in<Emphasis Type="Italic"> p53</Emphasis>-mutated bladder cancer cells

Purpose. It has been reported in several studies that the absence in cancer cells of the p53 tumor suppressor gene, mutations of which are frequently found in bladder cancer, increases their resistance to ionizing radiation. Other studies, however, suggest that mutations of the p53 gene could increase the radiosensitivity of cancer cells, although the evidence is still inconclusive. In the present study, we investigated the relationship between p53 status and radiation response in five different bladder cancer cell lines. Materials and Methods. Five different human bladder cancer cell lines (KK47: with wt-p53, RT4: with wt-p53, T24: with mutated p53, 5637: with mutated p53, UM-UC-3: with mutated p53) were used in the study. Cells were irradiated with 0, 2, 4, 6 or 8 Gy, then trypsinized and re-plated for clonogenic survival assay, quantitative RT-PCR assay, flow-cytometry analysis and TUNEL assay. Results. The clonogenic assay demonstrated that KK47 and RT4 had significantly higher radiosensitivity than other cell lines. Quantitative RT-PCR analysis showed that radiation induced increased expression of p53, Bax, and p21 mRNA in KK47 and RT4. After irradiation, G1 cell-cycle arrest was observed in KK47 and RT4 under flow cytometry analysis, while T24, 5637, and UM-UC-3 showed an increase in the proportion of G2 cells. Increased cell apoptosis was also observed under TUNEL assay in KK47 and RT4, but not in other cell lines. Conclusions: It was demonstrated that ionizing radiation induces p53-dependent cell apoptosis in bladder cancer cells with wt-p53 but not in those with mutated p53.     

The value of EZH2, p27kip1, BMI‐1 and MIB‐1 on biopsy specimens with low‐risk prostate cancer in selecting men with significant prostate cancer at prostatectomy

OBJECTIVE

To assess the additional prognostic value of the molecular markers EZH2, MIB‐1, p27^kip1 and BMI‐1 on needle biopsies from men with low‐risk prostate cancer, as this disease in needle biopsies shows a heterogeneous clinical outcome, and while it is known that the expression of these tissue markers is predictive of the clinical outcome after radical prostatectomy (RP) their value in prostate biopsies is largely unknown.

PATIENTS AND METHODS

The study included men participating in a screening study, diagnosed with low‐risk prostate cancer and subsequently treated with RP. Immunohistochemical staining for EZH2, MIB‐1, p27^kip1 and BMI‐1 on the needle biopsies were (semi)quantitatively scored and expression levels were related to significant disease at RP. Clinical low‐risk prostate cancer was defined as a prostate‐specific antigen (PSA) level of ≤10 ng/mL, clinical T‐stage ≤2, biopsy Gleason score ≤6, a PSA density of <0.20 ng/mL/g and two or fewer positive cores. Significant PC at RP was defined as presence of any of extracapsular extension, Gleason pattern 4/5, or tumour volume ≥0.5 mL.

RESULTS

In all, 86 biopsy specimens were included; there was high EZH2 expression (>1.0%) in 42% and a low p27^kip expression (<90%) in 63%. Significant disease was present in 44 (51%) RP specimens. A high EZH2 (odds ratio 3.19, P = 0.043) and a low p27^kip1 (4.69, P = 0.036) were independent predictors for significant prostate cancer at RP.

CONCLUSIONS

The determination of EZH2 and p27^kip1 on diagnostic needle biopsies supports the selection of men with indolent prostate cancer at RP. Especially p27^kip1 could improve the pretreatment risk assessment of patients with low‐risk prostate cancer.     

Adenovirus-mediated wild-typep53 tumor suppressor gene therapy induces apoptosis and suppresses growth of human pancreatic cancer

Background: Thep53 tumor suppressor gene is mutated in up to 70% of pancreatic adenocarcinomas. We determined the effect of reintroduction of the wild-typep53 gene on proliferation and apoptosis in human pancreatic cancer cells using an adenoviral vector containing the wild-typep53 tumor suppressor gene. Methods: Transduction efficiencies of six p53-mutant pancreatic cancer cell lines (AsPC-1, BxPC-3, Capan-1, CFPAC-1, MIA PaCa-2, and PANC-1) were determined using the reporter gene construct Ad5/CMV/-gal. Cell proliferation was monitored using a³H-thymidine incorporation assay, Western blot analysis forp53 expression was performed, and DNA laddering and fluorescence-activated cell sorter analysis were used to assess apoptosis.p53 gene therapy was tested in vivo in a subcutaneous tumor model. Results: The cell lines varied in transduction efficiency. The MIA PaCa-2 cells had the highest transduction efficiency, with 65% of pancreatic tumor cells staining positive for beta-galactosidase (-gal) at a multiplicity of infection (MOI) of 50. At the same MOI, only 15% of the CFPAC-1 cells expressed the -gal gene. Adenovirus-mediatedp53 gene transfer suppressed growth of all human pancreatic cancer cell lines in a dose-dependent manner. Western blot analysis confirmed the presence of the p53 protein product at 48 hours after infection. DNA ladders demonstrated increased chromatin degradation, and fluorescence-activated cell sorter analysis demonstrated a four-fold increase in apoptotic cells at 48 and 72 hours following infection with Ad5/CMV/p53 in the MIA PaCa-2 and PANC-1 cells. Suppression of tumor growth mediated by induction of apoptosis was observed in vivo in an established nude mouse subcutaneous tumor model following intratumoral injections of Ad5/CMV/p53. Conclusions: Introduction of the wild-typep53 gene using an adenoviral vector in pancreatic cancer withp53 mutations induces apoptosis and inhibits cell growth. These data provide preliminary support for adenoviral mediatedp53 tumor suppressor gene therapy of human pancreatic cancer.Presented at the 51st Annual Cancer Symposium of The Society of Surgical Oncology, San Diego, California, March 26–29, 1998.     

Overexpression ofBax sensitizes breast cancer MCF-7 cells to cisplatin and etoposide

Bax, one of thebcl-2 family genes, is expressed in a number of untransformed cell lines and various breast tissues, whereas only weak or no expression has been detected in breast cancer cell lines and malignant breast tissue. Human breast cancer MCF-7 cells, which have a weakbax gene expression, were stably transfected withpCX2neo bax, encoding humanbax; and two unique clones,MCF-7/bax-1 andMCF-7/bax-2, that expressed different levels ofbax were generated. Sensitivity to cisplatin (CDDP) and etoposide (VP-16) was examined and each stable transfectant was more sensitive to these agents than the parental MCF-7 cells. The degree of enhancement in sensitivity to these anticancer agents was dependent on the expression level ofbax. The enzyme-linked immunosorbent assay (ELISA), which quantifies DNA damage, demonstrated that this sensitization was due to apoptosis. Thus, we suggest that exogenousbax-α overexpression may be one of the factors determining cellular chemosensitivity in MCF-7 breast cancer cells and that it could be applied therapeutically to enhance chemosensitivity in breast cancer cells.     

Inactivation of tumor suppressor genes and deregulation of the c-myc gene in urothelial cancer cell lines

Recent investigations have demonstrated p53 and Rb alterations in a subset of transitional cell carcinoma (TCC). Further genetic changes during tumor progression include overexpression of the c-myc gene in a significant number of mainly invasive bladder tumors. To study the possible interactions between these genes in TCC, urothelial cancer cell lines were chosen as an in vitro model. Expression and mutation of p53 was studied in 15 bladder cancer cell lines by immunocytochemistry, Western blot, polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) analysis and direct sequencing of double stranded PCR products of exons 4, 5, 7 and 8 of genomic DNA. C-myc expression and gene structure were studied using Northern and Southern blot techniques. Rb protein expression was analyzed by Western blot. Twelve of 15 cell lines showed either p53 mutations or abnormal protein expression. Consistent with previous studies, five cell lines did not express Rb protein. None of the cell lines studied retained both tumor suppressor genes in a functional form. The c-myc gene appeared to be intact in all cell lines and copy numbers were close to normal. Northern analysis demonstrated that all cell lines expressed c-myc mRNA but evidence for altered regulation was found in at least two cell lines. Our data suggest that amplification or translocation are not the underlying mechanism for c-myc overexpression in urothelial tumors. No correlation between loss of Rb protein and c-myc expression was observed. The results presented here for the cell lines match well those obtained in vivo. Thus, these cell lines may provide a suitable model for further analysis of molecular alterations in urothelial cancer.     

c-myc oncoprotein levels in bladder cancer

Summary The protein coded by the oncogene c-myc, p62^c-myc, was measured using monoclonal antibodies and flow cytometry in nuclei derived from paraffin-wax sections of transitional cell carcinomas of the human bladder. Superficial disease (stages pTa and pT1) which did not recur within 5 years of diagnosis had significantly higher oncoprotein levels than those which did recur or were muscle-invasive (stage pT2 or greater) at presentation (P<0.01). These preliminary findings indicate that oncoprotein levels might have prognostic significance for bladder cancer.     

Immunoreactivity of p27<Superscript>(Kip1)</Superscript>, cyclin D3, and Ki67 in conventional renal cell carcinoma

The goal of the study was to evaluate expression of the cell-cycle regulatory proteins (p27^(Kip1) and cyclin D3) and proliferation marker Ki67 in normal human kidneys and renal cell carcinoma (RCC) tissues. Intensity of the markers’ expression was prospectively studied and compared between normal and RCC tissue samples. Association was analyzed with cancer clinical parameters. p27^(Kip1) was significantly upregulated in normal compared with in RCC samples. Immunoreactivity of the protein negatively correlated with tumor size and was associated with pathological stage and grade. Patients with symptomatic disease had significantly less marker expression than those with incidentally discovered tumors. Intensity of Ki67 staining positively correlated with primary tumor size and associated with disease stage and grade. Cyclin D3 immunoreactivity positively correlated with tumor size. Loss of p27^(Kip1) expression, pathological stage, grade, and tumor size were risk factors for disease recurrence (P = 0.0072, 0.0011, and 0.0467, and P < 0.0001, respectively) and patient death (P = 0.0021, 0.0106, 0.0151, and 0.0021, respectively). With Cox multivariate analysis loss of p27^(Kip1) expression (hazard ratio 9.3, P = 0.002) and tumor size (hazard ratio 5.9, P = 0.015) were the predictors of cancer-specific survival. In conclusion, intensity of the markers’ expression in RCC is associated with tumour clinical parameters (size, stage, grade, and disease presentation type). Loss of p27^(Kip1) expression is a risk factor for the disease recurrence and cancer-related patient death.     

Cell death induced by down-regulation of heat shock protein 70 in lung cancer cell lines is p53-independent and does not require DNA cleavage

Objective

The inducible form of heat shock protein 70 is known to be overexpressed in tumors and seems to be necessary for the survival of tumor cells via an unknown mechanism. We therefore evaluated whether selective depletion of heat shock protein 70 induces cell death in lung cancer cells.

Methods

An adenovirus expressing antisense heat shock protein 70 and an adenovirus with β-galactosidase were used for transduction of the lung cancer cell lines A549, NCI-H358, LXF-289, LOU-NH91, normal human bronchial epithelial cells, and normal lung fibroblasts IMR90. Cell death was determined by morphology, propidium iodide uptake, and trypan blue staining; DNA cleavage was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling. Expression of heat shock protein 70, heat shock cognate 70, and phosphorylated p53 was determined by Western blot analysis.

Results

Transduction of lung cancer cells with adenovirus expressing antisense heat shock protein 70 but not with adenovirus with β-galactosidase resulted in extensive cell death after 96 hours (A549: 53.2 ± 9.44% versus 12.9 ± 6.6%; NCI-H358: 48.4 ± 7.2% versus 25.2 ± 1.4%; LXF-289: 58.8 ± 6.5% versus 24.7 ± 5.4%; LOU-NH91: 82.5 ± 1.8% versus 38.5 ± 2.6%). In contrast, adenovirus expressing antisense heat shock protein 70 showed much less cytotoxicity in normal human bronchial epithelial cells (16.0 ± 0.5% versus 17.1 ± 7.3%) and in normal lung fibroblasts IMR90 (17.2 ± 3.6% versus 8.2 ± 1.6%). After treatment with adenovirus expressing antisense heat shock protein 70, transactivation of p53 in A549 but not in NCI-H358, a cell line deleted for p53 has been observed. Furthermore, 22.0 ± 3.0% of A549 cells treated for adenovirus expressing antisense heat shock protein 70 stained positive with terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling versus 10.2 ± 4.0% treated with control virus. This effect but not cell death itself was blocked by treatment with 10 μmol/L zVAD-fmk, a broad caspase inhibitor.

Conclusions

Selective down-regulation of heat shock protein 70 induces cell death in lung cancer but not in normal lung cells. The demonstrated effect is p53-independent and does not require DNA cleavage. The data suggest that gene transfer of antisense heat shock protein 70 might be useful in developing new strategies for the treatment of lung cancer.     

Biological and Genetic Characteristics of Tumor-Initiating Cells in Colon Cancer

Background Human prominin-1 (PROM1, CD133) was used as a marker to detect stem cells (progenitor cells) and cancer stem cells (tumor-initiating cells) in various tissues. The purpose of this study was to investigate the biological and genetic characteristics of tumor-initiating cells in colon cancer with both in vitro and in vivo analyses. Methods The CD133 expression of 12 colon cancer cell lines was evaluated. CD133⁺ cells were isolated by flow cytometry and examined for in vivo tumor formation, in vitro proliferation, colony formation, and invasion ability. Additionally, we used microarray analysis to compare gene expression profiles between CD133⁺ and CD133^– isolated cells. Results CD133⁺ cells were found in 5 of 12 colon cancer cell lines. Isolated CD133⁺ cells from the HT29 colon cancer cell line exhibited a higher tumorigenic potential than CD133^– cells in the in vivo tumor formation assay. Furthermore, it was shown that CD133⁺ cells are more proliferative and have higher colony-forming and invasive abilities than CD133^– cells in vitro. Microarray analysis found differential gene expression correlating with CD133 expression. Conclusions It was confirmed that CD133⁺ cells in colon cancer are useful markers for the detection of tumor-initiating cells. Intimate biological and genetic features of CD133⁺ cells in colon cancer cell lines were also revealed. The biological characteristics of CD133⁺ cells and differentially expressed genes in these cells will help elucidate more details of tumor-initiating cells in colon cancer. Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users