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G N Thalmann

Publications and source records attributed to G N Thalmann.

16 recordsLinked to original sources
PubMed2000

LNCaP progression model of human prostate cancer: androgen-independence and osseous metastasis.

BACKGROUND: Clinically, the lethal phenotypes of human prostate cancer are characterized by their progression to androgen-independence and their propensity to form osseous metastases. We reported previously on the establishment of androgen-independent (AI) human prostate cancer cell lines derived from androgen-dependent (AD) LNCaP cells, with androgen independence defined as the capability of prostate cancer cells to grow in castrated hosts. One of the sublines, C4-2, was found to be AI, highly tumorigenic, and metastatic, having a proclivity for metastasis to the bone. METHODS: We established the AI and bone metastatic cell sublines B2, B3, B4, and B5 from the parental C4-2 subline, using a previously established coinoculating procedure. We determined the biologic behavior of the parental and derivative LNCaP sublines in vivo and in vitro, as well as their molecular and cytogenetic characteristics. RESULTS: Unlike other human prostate cancer models, the LNCaP progression model shares remarkable similarities with human prostate cancer. We observed a comparable pattern of metastasis from the primary to the lymph node and to the axial skeleton, with a predominant phenotype of osteoblastic reaction; 25-37.5% of the animals developed paraplegia. Cytogenetic and biochemical characterizations of LNCaP sublines also indicate close similarities between human prostate cancer and the LNCaP progression model. Additional chromosomal changes were detected in B2-B5 sublines derived from C4-2 bone metastases. These LNCaP sublines were found to grow faster under anchorage-dependent but not -independent conditions. The in vitro invasion and in vivo metastatic potential of these LNCaP sublines surprisingly correlated with anchorage-dependent and not -independent growth. The derivative LNCaP sublines when cultured in vitro produced a substantially higher (20-30-fold) amount of basal steady-state concentrations of PSA than that of the parental LNCaP cells. PSA production was high initially, but was markedly reduced when the derivative cell lines were inoculated and allowed to grow long-term in vivo for the establishment of tumors and metastasis, suggesting that unknown host factors derived either from the prostate or the bone can effectively downregulate PSA expression by prostate tumor epithelium. CONCLUSIONS: The LNCaP model of human prostate cancer progression will help improve our understanding of the mechanisms of androgen-independence and osseous metastasis, and tumor-host determinants of PSA expression.

Animals↗
PubMed1999

Transurethral thermotherapy for benign prostatic hyperplasia significantly decreases infravesical obstruction: results in 134 patients after 1 year.

PURPOSE: We prospectively evaluated a decrease in outflow obstruction caused by benign prostatic hyperplasia (BPH) with second generation thermotherapy. MATERIALS AND METHODS: Transurethral microwave therapy was given with local anesthesia to 134 patients with urodynamically and cystoscopically documented obstruction by BPH and preserved detrusor function. Of 134 patients 67 (50%) had a general health score of 3 or greater. RESULTS: Urgency was the main complaint during thermotherapy. After a median followup of 24 months (minimum 12) 100 patients were evaluable at 6 and 12 months. Of the initial 134 patients 17 (13%) who required additional treatment (repeat thermotherapy, transurethral prostatic resection, permanent cystostomy), 7 who died during followup for treatment unrelated reasons and 10 who were lost to followup or refused evaluation were excluded from further analysis. Mean International Prostate Symptom Score decreased from 22.5 before to 3.6 at 6 months after treatment and remained stable at 12 months. Mean Quality of Life Index improved from 4.3 before to 1 at 12 months after treatment. Mean maximum flow increased from 7.3 ml. per second before to 14.5 at 6 months and 13.9 at 12 months after treatment. Mean post-void residual decreased from 199 to 34.8 and 37.2 ml. at 6 and 12 months, respectively. Urodynamic evaluation of 84 patients after 6 months revealed a decrease in mean detrusor opening pressure from 96.8 to 53 cm. water and mean detrusor pressure at maximum flow from 99.8 to 59.7 cm. water. Mean ultrasonographic prostate volume decreased from 57.6 to 42.4 cc and a cavity in the prostate was documented in 65 of the 84 cases (77%). All changes between the pretreatment and posttreatment values at 6 and 12 months, respectively, were statistically significant (paired t test p<0.00001). CONCLUSIONS: Targeted transurethral thermotherapy with second generation microwave equipment is minimally invasive, easy to apply and generally well tolerated with local anesthesia. Infravesical outlet obstruction and voiding pressures as assessed by pressure flow studies significantly decreased 6 months after treatment. Subjective voiding symptoms as well as post-void residual urine were significantly decreased, and urinary flow was improved 6 and 12 months after treatment of documented BPH.

Aged↗
PubMed1999

Osteopontin: possible role in prostate cancer progression.

Human prostate cancer has the propensity to metastasize to the bone where reciprocal cellular interactions between prostate cancer and bone cells are known to occur. Osteopontin (OPN), a noncollagenous bone extracellular matrix, is a secreted adhesive glycoprotein with a functional RGD cell-binding domain that interacts with the alpha(v)beta3 cell surface integrin heterodimer. OPN has been associated with malignant transformation as well as being ligand to the CD44 receptor. Polyclonal antibodies to human OPN (hOPN) were prepared, and specificity was shown by preabsorption with recombinant hOPN. The stimulatory effect of hOPN protein and the inhibitory effect of hOPN antibody on human prostate cancer cell lines LNCaP and C4-2 were assessed by induction or inhibition of anchorage-independent growth, respectively. Expression of hOPN mRNA in prostate cancer cell lines and human prostate cancer tissue specimens were measured by mRNA blot analysis. Protein expression was assessed by immunohistochemistry in human prostate cancer specimens and by Western blot analysis in prostate cancer cell lines. hOPN stimulated anchorage-independent growth of the human prostate cancer cell lines LNCaP and C4-2 in vitro. Antibodies to hOPN inhibited the growth-stimulatory effect by endogenous OPN, which can be overcome by the addition of exogenous hOPN. hOPN mRNA and protein are expressed in human prostate cancer cell lines in vitro and in clinical human prostate cancer specimens. These findings taken together suggest that OPN may act as a paracrine and autocrine mediator of prostate cancer growth and progression.

Animals↗
PubMed1998

Establishing human prostate cancer cell xenografts in bone: induction of osteoblastic reaction by prostate-specific antigen-producing tumors in athymic and SCID/bg mice using LNCaP and lineage-derived metastatic sublines.

LNCaP lineage-derived human prostate cancer cell lines C4-2 and C4-2B4 acquire androgen independence and osseous metastatic potential in vivo. Using C4-2 and C4-2B4 the goals of the current investigation were 1) to establish an ideal bone xenograft model for prostate cancer cells in intact athymic or SCID/bg mice using an intraosseous route of tumor cell administration and 2) to compare prostate cancer metastasis by administering cells either through intravenous (i.v.) or intracardiac administration in athymic or SCID/bg mice. Subsequent to tumor cell administration, prostate cancer growth in the skeleton was assessed by radiographic bone density, serum prostate-specific antigen (PSA) levels, presence of hematogenous prostate cancer cells and histopathologic evaluation of tumor specimens in the lymph node and skeleton. Our results show that whereas LNCaP cells injected intracardially failed to develop metastasis, C4-2 cells injected similarly had the highest metastatic capability in SCID/bg mice. Retroperitoneal and mediastinal lymph node metastases were noted in 3/7 animals, whereas 2/7 animals developed osteoblastic spine metastases. Intracardiac injection of C4-2 in athymic hosts produced spinal metastases in 1/5 animals at 8-12 weeks post-injection; PC-3 injected intracardially also metastasized to the bone but yielded osteolytic responses. Intravenous injection of either LNCaP or C4-2 failed to establish tumor colonies. Intrailiac injection of C4-2 but not LNCaP nor C4-2B4 cells in athymic mice established rapidly growing tumors in 4/8 animals at 2-7 weeks after inoculation. Intrafemoral injection of C4-2 (9/16) and C4-2B4 (5/18) but not LNCaP (0/13) cells resulted in the development of osteoblastic bone lesions in athymic mice (mean: 6 weeks, range: 3-12 weeks). In SCID/bg mice, intrafemoral injection of LNCaP (6/8), C4-2 (8/8) and C4-2B4 (8/8) cells formed PSA-producing, osteoblastic tumors in the bone marrow space within 3-5 weeks after tumor cell inoculation. A stepwise increase of serum PSA was detected in all animals. Reverse transcription-polymerase chain reaction (RT-PCR) to detect hematogenously disseminated prostate cancer cells could not be correlated to either serum PSA level or histological evidence of tumor cells in the marrow space. We have thus established a PSA-producing and osteoblastic human prostate cancer xenograft model in mice.

Animals↗
PubMed1997

Abnormal p53 expression is rare in clinically localized human prostate cancer: comparison between immunohistochemical and molecular detection of p53 mutations.

BACKGROUND: We assessed the frequency and molecular basis of p53 mutations in clinically localized prostatic adenocarcinoma. METHODS: Prostate specimens were examined from 100 patients with clinically localized prostatic adenocarcinoma and 13 patients with benign prostatic hyperplasia (BPH). Mutations producing nuclear accumulation of p53 were detected immunohistochemically. Exon-specific mutations were analyzed by polymerase chain reaction amplification and single strand conformation polymorphism (PCR-SSCP) and sequenced. RESULTS: p53 accumulation was detected in 5 tumors using antibody DO-1, and in 4 of these using antibody PAb 1801, but not in BPH. PCR-SSCP detected mutations in all 5 tumors, with alterations in exon 5 for 1 tumor, exon 6 for 3 tumors, and exon 7 for 1 tumor. An exon 6 mutation was also found in a tumor with no anti-p53 staining. CONCLUSIONS: p53 mutations are uncommon in clinically localized prostatic adenocarcinoma and absent from BPH. 5 of the 6 mutations were derived from locally invasive, prostate carcinomas, supporting the hypothesis that mutation of p53 is a late event in prostate carcinoma progression.

Adenocarcinoma↗
PubMed1997

Immunohistochemical determination of p53 overexpression. An easy and readily available method to identify progression in superficial bladder cancer?

Overexpression of p53, as determined by immunohistochemical staining with the murine monoclonal antibody DO7, was determined in specimens of 46 primary superficial transitional cell bladder tumours (14 TaG2, 10 T1G2, 22 T1G3). A colon cancer specimen served as a positive control and normal mesenchymal cells in the specimens served as an internal negative control. An exceptionally high proportion 36/46 (78%) of the specimens were found to stain positively for p53 in over 20% of the cell nuclei. After a median follow-up of 7 years, ten patients developed progressive disease. Of these ten patients nine demonstrated p53 positivity, resulting in a sensitivity of 90%. However, 27 of the overall 36 patients (75%) with p53-positive tumours did not progress to a higher stage or metastatic disease. These findings suggest that p53 overexpression is not of predictive prognostic value in superficial transitional cell carcinoma. With 7 of 14 specimens (50%) of Ta tumours overexpressing p53, the results were suggestive of p53 mutation being an early event in carcinogenesis. When the threshold was set at 50% of the cell nuclei overexpressing p53, 16/46 (35%) classified as p53 positive. Of the 16 tumours staining positively for p53, 7 (46%) progressed and 9 (56%) did not. None of the Ta and 16 (50%) of the T1 tumours classified as positive. This more stringent definition of positivity still does not identify p53 positivity as a single prognostic factor. With 50% of T1 tumours classifying as positive, we still find that p53 mutation may be an early event in carcinogenesis of bladder cancer.

Adult↗
PubMed1997

Genetic changes associated with the acquisition of androgen-independent growth, tumorigenicity and metastatic potential in a prostate cancer model.

Genetic changes underlying the progression of human prostate cancer are incompletely understood. Recently, an experimental model system that resembles human prostate cancer progression was developed based on the serial passage of an androgen-responsive, non-tumorigenic LNCaP prostate cancer cell line into athymic castrated mice. Six different sublines, derived after one, two or three rounds of in vivo passage, sequentially acquired androgen independence and tumorigenicity as well as metastatic capacity. Here, we used comparative genomic hybridization (CGH) and locus-specific fluorescence in situ hybridization (FISH) analysis to search for genetic changes that may underlie the phenotypic progression events in this model system. Six genetic aberrations were seen by CGH in the parental LNCaP cell line. The derivative sublines shared virtually all these changes, indicating a common clonal origin, but also contained 3-7 additional genetic changes. Gain of the 13q12-q13 chromosomal region as well as losses of 4, 6q24-qter, 20p and 21q were associated with androgen independence and tumorigenicity with additional changes correlating with metastasis. In conclusion, an accumulation of genetic changes correlates with tumour progression in this experimental in vivo model of prostate cancer progression. It is possible that the specific chromosomal aberrations involved in this model system may provide clues to the location of genes involved in human prostate cancer progression and metastasis.

Androgens↗
PubMed1997

Can cancer cells transform normal host cells into malignant cells?

A human prostate tumour cell line, LNCaP C4-2, when injected into athymic male nude mice, produced tumours containing: (1) only human cancer cells similar to those injected; (2) only murine stromal cells containing abnormal chromosome constitutions; or (3) both human prostate cancer cells similar to those injected and the transformed murine stromal cells with altered chromosome constitutions. Karyotypic analysis of murine metaphases from all the host-derived tumours showed mostly pseudodiploid chromosome constitutions, with multiple copies (amplification) of mouse chromosome 15 and the absence of a typical Y chromosome. Fluorescence in situ hybridization analysis of these murine cells, using a biotin-labelled total human DNA painting probe, further demonstrated the absence of human DNA and the presence of only mouse metaphase and interphase cells in these transformed stromal cells. These results suggest that cancer cells are capable of inducing neoplastic transformation in stromal cells of the host organ by some, as yet unknown, epigenetic mechanism(s).

Animals↗
PubMed1997

Interleukin-8 expression in the urine after bacillus Calmette-Guerin therapy: a potential prognostic factor of tumor recurrence and progression.

PURPOSE: We assessed whether interleukin-8 (IL-8), one of the first cytokines expressed in the urine after bacillus Calmette-Guerin (BCG) therapy for superficial urothelial tumors, may serve as a prognostic factor for treatment response. MATERIALS AND METHODS: Of 20 patients with superficial urothelial cancer of the urinary tract treated with BCG 13 had superficial bladder cancer and 7 received BCG perfusion of the upper urinary tract due to inoperability, solitary kidney, renal insufficiency or bilateral disease. After intravesical instillation of 120 mg. BCG or after 2-hour perfusion of the upper urinary tract with 360 mg. BCG urine was collected at 6-hour intervals. IL-8 was determined by solid phase double ligand enzyme-linked immunosorbent assay. RESULTS: IL-8 was stable in the urine for more than 48 hours. At a median followup of 36.5 months treatment failure occurred in 10 of the 20 patients, including 3 with recurrence, 6 with progressive disease and 1 with extensive carcinoma in situ. IL-8 excretion was more than 4,000 ng. in the first 6 hours after BCG therapy in all 10 patients who remained disease-free. In 9 of the 10 patients with recurrent disease IL-8 excretion was less than 4,000 ng. in the first 6 hours after BCG therapy. Patients secreting less than 4,000 ng. IL-8 into the urine during the first 6 hours after BCG therapy had a significantly higher risk of tumor recurrence and progression (p <0.0002). CONCLUSIONS: Due to its stability and kinetics IL-8 determined in urine collected during the first 6 hours after BCG therapy may prove to be a prognostic factor for tumor recurrence and progression after BCG therapy.

Adjuvants, Immunologic↗
PubMed1997

[Long-term urodynamic and clinical follow-up in 70 patients with ileal bladder replacement combined with an antireflux mechanism or an afferent tubular segment].

OBJECTIVES: A low-pressure ileal bladder replacement does not have any coordinated contraction during micturition, which is why we have evaluated various antireflux mechanisms in the context of a randomized prospective study. MATERIAL AND METHODS: 70 patients undergoing low-pressure ileal bladder replacement were randomized into 2 groups. An antireflux mechanism was performed in 35 patients and an afferent tubular segment was performed in the other 35 patients. RESULTS: After a median follow-up of 57 and 45 months respectively, the functional capacity of the reservoir, incidence of urinary tract infections, urinary continence, voiding havits, and serum urea and creatinine were similar in the two groups. 11/67 (16.5%) evaluable ureteropelvic units with an antireflux mechanism and 2/69 (3%) units with an afferent tubular segment developed major dilatation due to stenosis of the antireflux mechanism or the ureteroileal anastomosis (Fisher's exact test, p < 0.009). No radiological reflux could be demonstrated during micturition in either group. A simultaneous increase of intravesical, intraabdominal and intrapelvic pressure was observed during a Valsalva manoeuvre. CONCLUSION: Protection of the upper urinary tract by an ileal afferent tubular segment has yet to be confirmed in a larger series of patients with a longer follow-up. Our results show that prevention of reflux is less important in the case of orthotopic low-pressure ileal bladder replacement. Consequently, creation of an antireflux mechanism, associated with a high complication rate, is probably not justified.

Adult↗
PubMed1996

Molecular therapy with recombinant p53 adenovirus in an androgen-independent, metastatic human prostate cancer model.

The lethal phenotypes of advanced prostate cancer are androgen independent (AI) and metastatic to the axial skeleton. Our laboratory has developed an AI mouse model of metastatic human prostate cancer. In this communication, we report the development of tumor suppressor gene therapy in this AI and metastatic (C4-2) cancer model. By using recombinant adenovirus as a delivery vehicle, we introduced a wild-type p53 tumor suppressor gene into prostate cancer cell lines. Despite a silent mutation at codon 152 of the p53 gene, C4-2 cells express functional, but low, levels of p53 protein. However, the other prostatic cell lines, PC-3 and DU145, have a deletion mutation and two point mutations of the p53 gene, respectively. In vitro studies showed that cell growth, as measured by the thymidine incorporation assay, was inhibited in the C4-2, PC-3, and DU145 cells infected with wild-type p53 adenovirus in comparison to control viruses. Recombinant wild-type p53 adenovirus inhibited prostate tumor growth and its production of prostate-specific antigen (PSA) when injected into C4-2 tumors in nude mice. All p53-treated mice were tumor free as long as 12 weeks after cessation of the 8-week treatment regimen. Two of 8 p53-treated mice developed small tumors growing at distant sites after a prolonged period of follow-up observation. Moreover, other AI prostate cancer cells, PC-3 and DU145, treated with Ad5-CMV-p53 failed to develop into tumors in vivo. This gene therapy strategy may be used against AI prostatic cancer regardless of p53 gene mutation status.

Adenoviruses, Human↗
PubMed1996

Suramin-induced decrease in prostate-specific antigen expression with no effect on tumor growth in the LNCaP model of human prostate cancer.

BACKGROUND: Suramin, a polysulfonated naphthylurea and a recognized antitrypanosomal agent, has shown some promise in phase II clinical trials in the management of hormone-refractory human prostate cancer. Reduction of serum prostate-specific antigen (PSA) levels has been proposed as an end point for evaluating the antitumor efficacy of treatments for hormone-refractory prostate cancer. PURPOSE: We examined the antitumor effect of suramin in an in vivo mouse model of hormone-refractory human prostate cancer to determine whether a decrease in PSA levels reflects a reduction in tumor growth (volume). The tumors were induced in castrated, athymic nude mice by use of the androgen-independent, tumorigenic human prostate cancer cell line C4-2, which is a subline of the androgen-dependent, parental nontumorigenic cell line LNCaP. We also evaluated the effects of suramin in vitro on cell growth and the expression of PSA messenger RNA (mRNA) in both LNCaP and C4-2 cells. METHODS: For the in vivo studies, 24 mice were given a subcutaneous injection of 5 x 10(6) C4-2 cells at each of four sites. Animals (n = 20) with tumor volumes greater than 1 mm3 or less than 5 mm3 were divided equally into two groups. Drug treatment was initiated in one group by administration of 1 mg suramin intraperitoneally, followed by 0.1 mg suramin at 10-day intervals to maintain constant serum levels. Tumor growth and PSA expression levels were monitored. For the in vitro studies, both LNCaP and C4-2 cells were exposed to 100-400 microgram/mL suramin, and cell growth was monitored by a quantitative crystal violet assay. PSA mRNA expression was assessed by northern blot analysis in cells treated with either 250 microgram/mL suramin, 400 ng/mL dihydrotestosterone (DHT) (positive control), or 0.5-75 microgram/mL hydrocortisone (to mimic the clinical use of hydrocortisone during suramin treatment to compensate for the loss of adrenocortical function). In some studies, the combined effect of DHT and suramin on PSA mRNA expression was also evaluated. A two-way analysis of variance was performed to evaluate the treatment differences, and P values were obtained from two-sided tests for statistical significance. RESULTS: In vivo, suramin did not significantly affect the growth of androgen-independent C4-2 tumors (relative to the growth of tumors in 5% glucose-treated control animals; P = .76). However, suramin significantly decreased the ratio of PSA level to tumor volume (ng/mL PSA per mm(3) of tumor) (P<.001). Mice developed bone metastases in both treatment arms. Suramin affected the in vitro growth of LNCaP cells but not of C4-2 cells. Suramin diminished PSA mRNA expression in both LNCaP and C4-2 cells grown in vitro. Hydrocortisone had no effect on PSA mRNA levels. CONCLUSIONS: Although suramin inhibited the growth of androgen-dependent LNCaP cells, it did not inhibit the growth of androgen-independent C4-2 cells either in vitro or in vivo. Suramin significantly decreased PSA mRNA expression in both cell lines in vitro and depressed serum PSA levels in mice bearing androgen-independent C4-2 tumors. IMPLICATIONS: PSA level should be used with caution as an end point in clinical trials using suramin therapy for hormone-refractory prostate cancer.

Analysis of Variance↗
PubMed1996

Antireflux nipples or afferent tubular segments in 70 patients with ileal low pressure bladder substitutes: long-term results of a prospective randomized trial.

PURPOSE: Intestinal low pressure orthotopic bladder substitutes have no major coordinated contractions during micturition. Therefore, the importance and type of reflux prevention were assessed in a prospective randomized study. MATERIALS AND METHODS: A total of 70 patients with an ileal low pressure bladder substitute was randomized to receive a nipple valve or an isoperistaltic afferent ileal tubular segment for reflux prevention. RESULTS: After median observation times of 57 and 45 months, respectively, the results regarding functional reservoir capacity, incidence of infected urine, urinary continence, voiding habits and serum electrolytes, urea and creatinine were similar in both groups. Severe upper tract dilatation due to ureteroileal or nipple stenosis occurred in 9 of 67 evaluable reno-ureteral units (13.5%) in patients with antireflux nipples and in 2 of 69 (3%) in patients with an afferent tubular segment. This difference in favor of the latter cases is significant (Fisher's exact test p < 0.03). Video urodynamics did not show reflux of contrast medium during voiding in either group. A simultaneous intravesical, intra-abdominal and intrapelvic pressure increase was noted during the Valsalva maneuver. CONCLUSIONS: While long-term upper tract preservation by an afferent tubular ileal segment must be confirmed in larger patient series with longer followup, our results indicate that reflux prevention in patients with orthotopic low pressure bladder substitutes is not a major concern and does not justify the use of antireflux mechanisms with a high complication rate.

Adult↗
PubMed1994

Androgen-independent cancer progression and bone metastasis in the LNCaP model of human prostate cancer.

Our laboratory has previously reported on the derivation of LNCaP cell sublines from LNCaP tumors maintained in castrated and intact athymic male mice. These LNCaP sublines differ from the parental line in tumorigenicity and androgen dependence. This paper demonstrates that one of these sublines acquired metastatic potential. When inoculated either s.c. or orthotopically, the C4-2 subline metastasized to the lymph node and bone with an incidence of 11-50%. Interestingly, the incidence of osseous metastasis was higher in castrated than in intact male hosts. We evaluated the chromosomal, immunohistochemical, and biochemical characteristics of the LNCaP sublines derived from C4-2 tumors that metastasized to the lymph node and bone. Cytogenetic analysis showed that all sublines were human and shared common marker chromosomes with the parental LNCaP cells. This experimental human prostate cancer model may permit, for the first time, the study of the molecular mechanisms underlying human prostate cancer metastasis.

Animals↗