Biomedical subjects

Jacek Pinski

Publications and source records attributed to Jacek Pinski.

13 recordsLinked to original sources

PubMed2006

Genistein-induced neuroendocrine differentiation of prostate cancer cells.

BACKGROUND: Neuroendocrine (NE) cells are present in normal prostate and their number appears to be increased in advanced prostate cancer (PCA). In this study, we studied the effect of the phytoestrogen, genistein, on NE differentiation of LNCaP cells in vitro. METHODS: Neuroendocrine marker expression of LNCaP cells exposed to genistein was measured by immunohistochemistry, Western blot, and real-time PCR methods. Western blot analysis was used to study cell cycle and signaling pathways induced by genistein treatment. RESULTS: Six days after continuous genistein treatment, the majority of genistein-surviving cancer cells underwent transdifferentiation into a NE-like phenotype overexpressing the NE markers chromogranin A, synaptophysin, serotonin, and beta-III tubulin. This NE differentiation process was associated with upregulation of the cell cycle modulators p21, p27, and p53, and activation of the MAPK and STAT3 pathways. CONCLUSION: Our data indicate that genistein evokes not only apoptosis but also NE transdifferentiation of PCA cells.

Antineoplastic Agents↗

PubMed2006

Prognostic significance of neuroendocrine expression in lymph node-positive prostate cancer.

OBJECTIVES: To evaluate the expression of chromogranin A, a marker for neuroendocrine (NE) differentiation, in patients with lymph node-positive prostate cancer to determine its prognostic significance. NE cells are involved in cellular growth and differentiation in both normal and pathologic conditions of the prostate. METHODS: We reviewed the data of 140 patients with lymph node-positive prostate adenocarcinoma treated with radical prostatectomy and pelvic lymphadenectomy. The median follow-up was 10.9 years (range 0.8 to 19.7). Immunohistochemical staining for chromogranin A was evaluated in areas of benign epithelium, primary prostate cancer, and lymph node metastasis. The association between chromogranin A expression and the clinical and pathologic factors (preoperative serum prostate-specific antigen and prostatectomy Gleason score and stage) and clinical outcomes, including overall and recurrence-free survival, was evaluated. RESULTS: Staining was positive in 86% of benign areas, 61% of primary cancer specimens, and 12% of lymph node deposits. The preoperative serum prostate-specific antigen level and pathologic stage and grade of the primary tumor did not show any statistically significant correlation with NE staining in any of the areas. Only NE expression in the primary tumor was associated with clinical recurrence, with a 10-year recurrence-free survival rate for those with less than 5% staining of 67% compared with 35% for those with 5% staining or greater (P = 0.03). Furthermore, after adjusting for age, greater NE expression in the primary tumor (relative risk 2.15, P = 0.02) and lymph node deposit (relative risk 2.03, P = 0.03) was associated with poorer overall survival. CONCLUSIONS: NE expression in the primary tumor and lymph node metastasis of patients with node-positive prostate cancer may provide additional prognostic stratification.

Adenocarcinoma↗

PubMed2006

Evolving treatment paradigms for locally advanced and metastatic prostate cancer.

While men with early stage prostate cancer typically enjoy long-term survival after definitive management, for those who present with locally advanced or metastatic disease, survival is compromised. Multimodality therapy can prolong survival in these patients, with state-of-the-art options including intensity-modulated radiation or brachytherapy in conjunction with androgen ablation, adjuvant androgen ablation and/or chemotherapy with radical retropubic prostatectomy. In addition, novel biological therapies are being explored to target the unique molecular changes in prostate cancer cells and their interactions with the microenvironment. With these advances the outlook will undoubtedly improve, even for patients presenting with advanced disease. Careful application of these emerging therapies to a select group of prostate cancer patients most likely to obtain benefit from them is the challenge for urologists, medical oncologists and radiation oncologists for the future.

Antineoplastic Agents↗

PubMed2005

Prostate cancer metastases to bone: pathophysiology, pain management, and the promise of targeted therapy.

Bone metastases are a significant cause of pain and morbidity in prostate cancer, especially if they lead to complications such as pathological fractures and spinal cord compression. Palliation of pain can be achieved with radiation, radioisotopes, hormone therapy, chemotherapy, and bisphosphonates. Bisphosphonates also reduce the risk of skeletal complications. Studies with animal models and advances in understanding the molecular basis for bone metastases have yielded new targets for therapy. Some of the promising therapeutic trials are reviewed in this paper.

Animals↗

PubMed2005

Ethnic differences in neuroendocrine cell expression in normal human prostatic tissue.

OBJECTIVES: To determine whether any differences exist in neuroendocrine (NE) cell differentiation in normal prostates among various ethnic groups because the incidence and mortality from prostate cancer vary across racial groups. METHODS: Archived paraffin-embedded prostate samples not containing any malignancy were obtained from cystoprostatectomy specimens. Prostatic tissue was obtained from 15 African Americans, 13 Hispanics, 15 Asians, and 16 whites. NE cells were identified based on immunoreactivity for chromogranin A. The mean number of NE cells per high power field (HPF) for each patient was determined using a visual quantitative method by two observers who were unaware of the race of the patients. RESULTS: The geometric mean number of NE cells was 6.1/HPF for Asians, 5.6/HPF for whites, 4.0/HPF for Hispanics, and 0.7/HPF for African Americans. A highly significant difference was observed in the distribution of NE cells between African Americans and each of the other races (P < or =0.003). A trend toward greater NE expression was noted in Asians and whites compared with Hispanics; however, this difference did not reach statistical significance. CONCLUSIONS: We found a fivefold to eightfold difference in the distribution of NE cells in the normal prostates of African-American men compared with that of other races. The comparatively low NE cell expression in African-American men may play a role in the greater rate of prostate carcinogenesis seen in this ethnic group.

Black or African American↗

PubMed2005

Discovery and preclinical evaluation of a novel class of small-molecule compounds in hormone-dependent and -independent cancer cell lines.

We discovered a series of salicylhydrazide class of compounds with remarkable anticancer activity against a panel of hormone receptor-positive and -negative cell lines. In the present study, we evaluated the in vitro activity of SC21 and SC23 against a range of human tumor cell types and the in vivo efficacy of compound SC21 in a PC3 human prostate cancer xenograft model in mice. We also determined the effects of SC21 on cell cycle regulation and apoptosis. Our in vitro results show that salicylhydrazides are highly potent compounds effective in both hormone receptor-positive and -negative cancer cells. SC21 induced apoptosis and blocked the cell cycle in G(0)/G(1) or S phase, depending on the cell lines used and irrespective of p53, p21, pRb, and p16 status. SC21 effectively reduced the tumor growth in mice without apparent toxicity. Although the mechanism of action of SC21 is not completely elucidated, the effect on cell cycle, the induction of apoptosis and the activity against a panel of tumor cell lines of different origins prompted us to carry out an in-depth preclinical evaluation of SC21.

Animals↗

PubMed2005

Postchemotherapy residual masses in advanced seminoma: current management and outcomes.

Although pure testicular seminoma is most often confined to the testis, it can present with advanced-stage bulky retroperitoneal metastases in nearly a quarter of cases. While highly treatable with cisplatin-based chemotherapy, up to 80% of patients with advanced disease are found to have a radiographically detectable residual mass after chemotherapy. The management of these postchemotherapy residual masses remains controversial. Surgical resection is technically challenging due to a desmoplastic reaction resulting from seminoma treatment and regression. In addition, these residual masses often demonstrate a protracted period of regression that can span several months to years. Surveillance protocols, therefore, may be appropriate for most patients. Several retrospective studies have supported surgical resection only for discrete, well-delineated masses over 3 cm in size. Despite the highly radiosensitive nature of seminoma, radiation therapy in this setting has not been shown to provide significant benefit, and may limit the tolerability of subsequent salvage chemotherapy. The incorporation of noninvasive imaging modalities, such as positron emission tomography, into the management algorithm may better delineate the presence of viable residual tumor and thus allow better risk stratification.

Algorithms↗

PubMed2004

Inhibitory effect of IL-6-induced neuroendocrine cells on prostate cancer cell proliferation.

BACKGROUND: The role of increased neuroendocrine (NE) differentiation in prostate cancer (PCA) is not well understood. Long-term exposure of the prostate cancer cell line LNCaP to high concentrations of the cytokine interleukin-6 (IL-6) results in permanent transdifferentiation of these cells into a NE phenotype. In this study, we evaluated the effect of IL-6-induced NE cells on the growth of the PCA cell lines LNCaP, PC-3, and DU-145 in vitro. RESULTS: Co-culture of NE cells with PCA cells significantly inhibited DNA synthesis in all three PCA cell lines by 30-90% compared to controls. NE cell co-culture resulted in an increased percentage of PCA cells arrested in the S-phase of cell cycle and PCA cell apoptosis. CONCLUSIONS: Our results imply that NE cells suppress the proliferation of surrounding PCA cells by release of inhibitory factors.

Apoptosis↗

PubMed2004

Interleukin-6 inhibits the growth of prostate cancer xenografts in mice by the process of neuroendocrine differentiation.

In vitro, the human prostate cancer (PCA) cell line LNCaP can be permanently transdifferentiated into a quiescent neuroendocrine (NE) phenotype by the cytokine interleukin-6 (IL-6). Recently, we have shown that the growth of prostate cancer cells is significantly suppressed when cocultured with NE cells. In order to explore the inhibitory activity of IL-6 on prostate tumor growth, nude mice bearing xenografts of the PCA cell lines LNCaP and DU-145 (a line that is incapable of NE transdifferentiation by IL-6 in vitro) were treated with IL-6 for 3 weeks, either injected around the tumor or systematically released from implanted minipumps. Both administration forms of IL-6 inhibited the growth of LNCaP xenografts by more than 75% compared to the control group. In contrast, there was no difference in DU-145 tumor growth between IL-6-treated animals and controls. In comparison to control and DU-145 tumors, both IL-6 injected and pump-infused LNCaP tumors exhibited a significant increase in the expression of the NE markers neuron-specific enolase (NSE) and betaIII tubulin. Serum NSE levels were also significantly elevated in both IL-6-treated LNCaP tumor groups when compared to controls. IL-6 treatment resulted in G(0) cell cycle accumulation as evidenced by a loss of Ki-67 expression in > 90% of LNCaP tumor cells. These combined results demonstrate that IL-6-induced NE transdifferentiation of PCA cells has a significant inhibitory effect on tumor growth in mice. Agents, like IL-6, capable of NE transdifferentiation of PCA cells, should be considered as a new therapeutic approach for the treatment of prostate cancer.

Animals↗

PubMed2004

A new screening system for proliferation-independent anti-cancer agents.

An in vitro screen for identification of novel anti-cancer agents, which can induce proliferation-independent apoptosis of prostate cancer (PCA) cells, is required, since the proliferative growth fraction of human prostate cancers in patients is usually <10%. This is possible using the PCA cell line LNCaP, which can be permanently transdifferentiated into a quiescent neuroendocrine (NE) phenotype without undergoing apoptosis by the cytokine interleukine-6 (IL-6). Transdifferentiation of LNCaP cells into a NE phenotype was documented using western blot analysis and immunohistochemistry for the NE markers, neuron-specific enolase (NSE) and beta III tubulin. Accumulation of NE cells in the G0 phase of the cell cycle was demonstrated by Ki-67 immunohistochemistry. The effects of paclitaxel, vinblastine and thapsigargin (TG) on viability and apoptosis of NE and LNCaP cells were assessed by trypan blue exclusion and 4', 6-diamidino-2-phenylindole nuclear staining assays. In proliferating LNCaP cells, there was a significant decrease in viable cells after 48 h exposure to paclitaxel and vinblastine and a dramatic increase of apoptosis as compared with the controls. On the other hand, treatment with paclitaxel or vinblastine decreased the viability of NE cells only slightly without markedly increasing their rate of apoptosis compared to controls. In contrast, both LNCaP and NE cells showed a significant and comparable decrease in cell viability and similar high levels of apoptosis when treated with TG. These results demonstrate that terminally transdifferentiated NE cells represent a useful in vitro screening system for identification of novel anti-cancer agents, like TG, that can induce apoptosis without requiring proliferation.

Antineoplastic Agents↗

PubMed2004

Prognosis of patients with lymph node positive prostate cancer following radical prostatectomy: long-term results.

PURPOSE: We determined the prognostic factors that affect recurrence and survival in patients with lymph node positive prostate cancer. MATERIALS AND METHODS: Between 1972 and 1999, 1,936 patients underwent radical retropubic prostatectomy and pelvic lymph node dissection for clinically organ confined prostate cancer. A total of 235 patients (12.1%) were found to have disease metastatic to the lymph nodes (stage D1). Of the patients 69% received no adjuvant treatment. We reviewed the tumor stage (TNM), Gleason score, number and percent of involved lymph nodes (lymph node density), preoperative prostate specific antigen when available and adjuvant treatment. Overall survival and recurrence-free survival were estimated using Kaplan-Meier plots. RESULTS: Followup was 1 to 24 years (median 11.4). Overall median survival was 15 years. Overall clinical recurrence-free survival at 5, 10 and 15 years was 80%, 65% and 58%, respectively. Patients who had 1 or 2 positive lymph nodes had a clinical recurrence-free survival of 70% and 73% at 10 years, respectively, vs 49% in those who had 5 or more involved lymph nodes (p = 0.0031). When stratified by lymph node density, patients with a lymph node density of 20% or greater were at higher risk for clinical recurrence compared to those with a density of less than 20% (relative risk = 2.32, p <0.0001). On stratified log rank test only prostate cancer T stage, and the number and percent of positive lymph nodes correlated with recurrence-free and overall survival. CONCLUSIONS: Local tumor bulk and the number/percent of involved lymph nodes significantly affect disease progression and the survival rate. Radical prostatectomy may offer long-term survival in patients who have limited tumor bulk and nodal involvement.

Aged↗

PubMed2002

Trk receptor inhibition induces apoptosis of proliferating but not quiescent human osteoblasts.

Prostate cancer frequently metastasizes to the skeleton, producing painful osteoblastic lesions, which are associated with significant morbidity and mortality. This bone tropism involves the bidirectional paracrine interactions between prostate cancer cells and osteoblasts. These interactions enhance prostate cancer cell survival and proliferation of osteoblasts. Therefore, agents that can induce apoptosis of prostate cancer cells and proliferating osteoblasts would be highly advantageous. Previously, we have documented that the unique survival pathway for prostate cancer cells involves a neurotrophin/Trk receptor autocrine pathway. The indocarbazole compounds, CEP-701 and CEP-751, are potent inhibitor of this Trk receptor survival signaling and thus selectively induces apoptosis of prostate cancer cells in various in vitro and in vivo models. In this study, we documented the effects of CEP-751 on the conditionally immortalized osteoblastic cell line, hFOB, in vitro. At the permissive temperature of 34 degrees C, these cells express large T antigen, inducing their continuous proliferation, whereas at 39 degrees C, T antigen is degraded and the cells stop proliferating without undergoing apoptosis. Trk receptors are expressed in hFOB cells, as determined both by reverse transcription-PCR and Western blots. These osteoblasts were shown to produce nerve growth factor and brain-derived neurotrophic factor but not neurotrophin-3, as measured by ELISA. hFOB osteoblasts, cultured at 34 degrees C, secreted significantly (P < 0.01) more brain-derived neurotrophic factor and nerve growth factor into the medium than hFOB cells cultured at 39 degrees C. Because the Trk/neurotrophin axis is present in both proliferating and quiescent (i.e., nonproliferating) osteoblasts, the effects of 48 h of exposure to various doses of CEP-751 on cell viability and apoptosis of hFOB cells were assessed by trypan blue exclusion assays and 4',6-diamidino-2-phenylindole nuclear staining. Cell viability and apoptosis of hFOB cells at 34 degrees C were significantly and dose-dependently decreased compared with untreated proliferating cells. In contrast, even the highest concentration of CEP-751 (200 nM) did not affect cell viability and apoptosis of quiescent hFOB cells cultured at 39 degrees C. This trk inhibition-induced cytotoxicity was confirmed using early-passage, proliferating normal (i.e., non-SV40-transformed) human osteoblasts, which also express Trk receptor protein. These combined results demonstrate that proliferating osteoblasts acquire a sensitivity to trk inhibition- induced apoptosis not shared with normally quiescent osteoblasts.

Antineoplastic Agents↗

PubMedDate not supplied

Glucose metabolism of human prostate cancer mouse xenografts.

We hypothesized that the glucose metabolism of prostate cancer is modulated by androgen. We performed in vivo biodistribution and imaging studies of [F-18] fluorodeoxyglucose (FDG) accumulation in androgen-sensitive (CWR-22) and androgen-independent (PC-3) human prostate cancer xenografts implanted in castrated and noncastrated male athymic mice. The growth pattern of the CWR-22 tumor was best approximated by an exponential function (tumor size in mm3 = 14.913 e(0.1086 x days), R2 = .96, n = 5). The growth pattern of the PC-3 tumor was best approximated by a quadratic function (tumor size in mm3 = 0.3511 x days2 + 49.418 x day - 753.33, R2 = .96, n = 3). The FDG accumulation in the CWR-22 tumor implanted in the castrated mice was significantly lower, by an average of 55%, in comparison to that implanted in the noncastrated host (1.27 vs. 2.83, respectively, p < .05). The 3-week maximal standardized uptake value (SUVmax) was 0.99 +/- 0.43 (mean +/- SD) for CWR-22 and 1.21 +/- 0.32 for PC-3, respectively. The 5-week SUVmax was 1.22 +/- 0.08 for CWR-22 and 1.35 +/- 0.17 for PC-3, respectively. The background muscle SUVmax was 0.53 +/- 0.11. Glucose metabolism was higher in the PC-3 tumor than in the CWR-22 tumor at both the 3-week (by 18%) and the 5-week (by 9.6%) micro-PET imaging sessions. Our results support the notions that FDG PET may be useful in the imaging evaluation of response to androgen ablation therapy and in the early prediction of hormone refractoriness in men with metastatic prostate cancer.

Androgens↗