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Shahriar Koochekpour

Publications and source records attributed to Shahriar Koochekpour.

11 recordsLinked to original sources
PubMed2007

Prosaposin upregulates AR and PSA expression and activity in prostate cancer cells (LNCaP).

BACKGROUND: Prosaposin overexpression and/or genomic amplification have been demonstrated in androgen-independent (AI) prostate cancer cell lines and tissues. Here, we explored the possibility for a functional relationship between prosaposin and androgen receptor (AR) in LNCaP cells. METHODS: The effect of prosaposin or its active molecular derivatives (e.g., saposin C) on expression and activity of androgen receptor (AR) and prostate-specific antigen (PSA) was examined by using immunoblotting, RT-PCR, transfection, and reporter gene assays, immunofluorescence staining, and inhibitors of signal transduction pathways. RESULTS: Prosaposin or saposin C, in an AI-manner, (a) increased AR mRNA and protein expression and nuclear AR content and its phosphorylation state; (b) increased PSA mRNA and protein expression; and (c) upregulated PSA- and an androgen-inducible probasin (PB)-reporter gene activity in LNCaP and AR-transfected PC-3 cells. Induction of PSA expression and reporter activity was substantially blocked or prevented with the antiandrogen bicalutamide, pertussis toxin, or inhibitors of MAPK- and PI3K/Akt-signaling pathways, indicating an androgen-agonistic effect for saposin C that involves AR and multiple signaling pathways. CONCLUSIONS: The results for the first time introduce prosaposin as an androgen-agonist in prostate cancer cells. This finding, together with the growth-promoting effect and overexpression of prosaposin, may support a growth advantage to AI prostate cancer cells.

Androgen Antagonists↗
PubMed2007

Survivin is not only a death encounter but also a survival protein for invading tumor cells.

Cell proliferation and cell death pathways meet at a pivotal crossroad, crucial to maintain normal homeostasis and to eliminate dangerous cells before they start dividing. Survivin (SVV) is an intriguing and fascinating protein at this crossroad that interfaces life and death, through its dual role in facilitating cell division and encountering apoptosis. SVV's prominent expression in essentially all human malignancies, and low or no expression in most normal tissues, suggests that it would be an ideal target for cancer-directed therapy. However, SVV has been recently described as a target for fine tuning by alternative splicing mechanism generating five defined splice variants and a number of other uncharacterized/bizarre isoforms. This diversity indicates that SVV, in addition to its known functions in tumorgenesis, angiogenesis and cardiovascular diseases, might be associated with other unknown functions. Intriguingly, new accumulating evidence from our own work and others, suggest a novel role for SVV in the mechanisms of tumor invasion and metastasis. The SVV pathway has now provided tangible opportunities for targeted, rational cancer therapy. It is therefore an attractive and promising therapeutic target not only for cancer but also for other diseases. Although a number of studies utilizing SVV as an anti-cancer strategy are well underway, further investigation into the exact molecular interactions underpinning its functions is critical for the success of such trials. Impeding development of safe and effective SVV antagonists for clinical use is due to a lack of understanding the molecular mechanisms by which SVV differentially affects apoptosis and cell division in both normal and malignant cells. In this report, in addition to reviewing the SVV known functions, we discuss the newly proposed mechanisms by which SVV might serve as a survival tool for invading tumor cells.

Apoptosis↗
PubMed2006

Proline-, glutamic acid-, and leucine-rich protein-1/modulator of nongenomic activity of estrogen receptor enhances androgen receptor functions through LIM-only coactivator, four-and-a-half LIM-only protein 2.

Proline-, glutamic acid-, and leucine-rich protein-1 (PELP1) is a coregulator of multiple nuclear receptors. Molecular mechanisms of PELP1 function are not completely understood, but its expression is up-regulated in hormonal-dependent cancers. Using a yeast two-hybrid screen, we found that four-and-a-half LIM-only protein 2 (FHL2) interacted with PELP1. FHL2 is a transcriptional regulator that associates with nuclear cofactors, including androgen receptors (ARs), and contains an intrinsic activation domain. PELP1 and FHL2 interact in vitro and in vivo and colocalize in the nuclear compartment. PELP1 interacts with FHL2 via LIM domains 3 and 4 and synergistically enhances the transcriptional activity of FHL2. Src kinase is required for PELP1-mediated enhancement of FHL2 functions because knockdown of Src kinase expression or function abolished PELP1-mediated FHL2 activation functions. PELP1 interacted with AR and enhanced FHL2-mediated AR transactivation functions. PELP1 knockdown by small interfering RNA or PELP1 mutant, which lacks an activation domain, reduced FHL2-mediated AR transactivation. Biochemical analyses revealed a complex consisting of PELP1, FHL2, and AR in prostate cancer cells. PELP1/MNAR expression was elevated in high-grade prostate tumors. Our results suggest that PELP1 functions as a molecular adaptor, coupling FHL2 with nuclear receptors, and PELP1-FHL2 interactions may have a role in prostate cancer progression.

Animals↗
PubMed2006

Pleomorphic adenoma of the trachea in an 8-year-old boy: a case report.

We report a case of pleomorphic adenoma of the trachea in an 8-year-old boy who required emergency surgery for severe respiratory distress. Chest computed tomographic scan and bronchoscopy showed a relatively large mass in distal trachea and right main bronchus and destruction of the lung parenchyma. The patient was subjected to right carinal resection, pneumonectomy, and pericardial patch tracheoplasty for reconstruction of the trachea. Histopathological examination and immunohistochemical staining of tumor specimens were compatible with pleomorphic adenoma. Postoperative follow-up of this patient for a period of 6 months showed satisfactory results with no complications or tumor recurrence. We present not only a very rare benign tracheal tumor in children but also demonstrate successful usage of a free pericardial patch for tracheal reconstruction, although direct anastomosis failed to provide an adequate anastomotic lumen.

Adenoma, Pleomorphic↗
PubMed2005

Amplification and overexpression of prosaposin in prostate cancer.

We identified prosaposin (PSAP) as a secreted protein expressed in androgen-independent (AI) prostate cancer cells by cloning/sequencing, after probing a PC-3 cDNA library expressed in the lambdaTriplEx phagemid expression vector with a polyclonal rabbit antibody generated against pooled human seminal plasma. PSAP is a neurotrophic molecule; its deficiency or inactivation has proved to be lethal in man and mice, and in mice, it leads to abnormal development and atrophy of the prostate gland, despite normal testosterone levels. We used Southern hybridization, quantitative real-time polymerase chain reaction, and/or single nucleotide polymorphism (SNP) array analysis, and we now report the genomic amplification of PSAP in the metastatic AI prostate cancer cell lines, PC-3, DU-145, MDA-PCa 2b, M-12, and NCI-H660. In addition, by using SNP arrays and a set of 25 punch biopsy samples of human prostate cancer xenografts (LAPC3, LuCaP 23.1, 35, 49, 58, 73, 77, 81, 86.2, 92.1, 93, 96, 105, and 115), lymph nodes, and visceral-organ metastases, we detected amplification of the PSAP locus (10q22.1) in LuCaP 58 and 96 xenografts and two lymph node metastases. In addition, AI metastatic prostate cancer cell lines C4-2B and IA8-ARCaP over-expressed PSAP mRNA without evidence of genomic amplification. Taken together with prior data that demonstrated the growth-, migration-, and invasion-promoting activities, the activation of multiple signal transduction pathways, and the antiapoptotic effect of PSAP (or one of its active domains, saposin C) in prostate cancer cells, our current observation of PSAP amplification or overexpression in prostate cancer suggests, for the first time, a role for this molecule in the process of carcinogenesis or cancer progression in the prostate.

Blotting, Western↗
PubMed2005

Saposin C stimulates growth and invasion, activates p42/44 and SAPK/JNK signaling pathways of MAPK and upregulates uPA/uPAR expression in prostate cancer and stromal cells.

AIM: To determine the effect of saposin C (a known trophic domain of prosaposin) on proliferation, migration and invasion, as well as its effect on the expression of urokinase plasmonogen activator (uPA), its receptor (uPAR) and matrix metalloproteinases (MMP)-2 and -9 in normal and malignant prostate cells. In addition, we tested whether saposin C can activate p42/44 and stress-activated protein kinase/c-Jun NH2-terminal kinase (SAPK/JNK) signal transduction pathways of the mitogen-activated protein kinase (MAPK) superfamily. METHODS: We employed Western blot analysis, phospho-specific antibodies, cell proliferation assay, reverse transcriptase-polymerase chain reaction, in vitro kinase assays and migration and invasion to determine the effect of saposin C on various biological behaviors of prostate stromal and cancer cells. RESULTS: Saposin C, in a cell type-specific manner, upregulates uPA/uPAR and immediate early gene c-Jun expression, stimulates cell proliferation, migration and invasion and activates p42/44 and SAPK/JNK MAPK pathways in prostate stromal and cancer cells. Normal prostate epithelial cells were not responsive to saposin C treatment in the above studies. CONCLUSION: Saposin C functions as a multipotential modulator of diverse biological activities in prostate cancer and stromal cells. These results strongly suggest that saposin C functions as a potent growth factor for prostatic cells and may contribute to prostate carcinogenesis and/or the development of hormone-refractory prostate cancer.

Cell Division↗
PubMed2004

Saposin C promotes survival and prevents apoptosis via PI3K/Akt-dependent pathway in prostate cancer cells.

BACKGROUND: In addition to androgens, growth factors are also implicated in the development and neoplastic growth of the prostate gland. Prosaposin is a potent neurotrophic molecule. Homozygous inactivation of prosaposin in mice has led to the development of a number of abnormalities in the male reproductive system, including atrophy of the prostate gland and inactivation of mitogen-activated protein kinase (MAPK) and Akt in prostate epithelial cells. We have recently reported that prosaposin is expressed at a higher level by androgen-independent (AI) prostate cancer cells as compared to androgen-sensitive prostate cancer cells or normal prostate epithelial and stromal cells. In addition, we have demonstrated that a synthetic peptide (prosaptide TX14A), derived from the trophic sequence of the saposin C domain of prosaposin, stimulated cell proliferation, migration and invasion and activated the MAPK signaling pathway in prostate cancer cells. The biological significances of saposin C and prosaposin in prostate cancer are not known. RESULTS: Here, we report that saposin C, in a cell type-specific and dose-dependent manner, acts as a survival factor, activates the Akt-signaling pathway, down-modulates caspase-3, -7, and -9 expression and/or activity, and decreases the cleaved nuclear substrate of caspase-3 in prostate cancer cells under serum-starvation stress. In addition, prosaptide TX14A, saposin C, or prosaposin decreased the growth-inhibitory effect, caspase-3/7 activity, and apoptotic cell death induced by etoposide. We also discovered that saposin C activates the p42/44 MAP kinase pathway in a pertussis toxin-sensitive and phosphatidylinositol 3-kinase (PI3K) /Akt-dependent manner in prostate cancer cells. Our data also show that the anti-apoptotic activity of saposin C is at least partially mediated via PI3K/Akt signaling pathway. CONCLUSION: We postulate that as a mitogenic, survival, and anti-apoptotic factor for prostate cancer cells, saposin C or prosaposin may contribute to prostate carcinogenesis at its early androgen-dependent or metastatic AI state.

Apoptosis↗
PubMed2004

Prosaptide TX14A stimulates growth, migration, and invasion and activates the Raf-MEK-ERK-RSK-Elk-1 signaling pathway in prostate cancer cells.

BACKGROUND: Prosaposin is a neurotrophic factor. Prosaposin knock-out mice have been reported to develop a number of abnormalities, including atrophy of the prostate gland and mitogen-activated protein kinase (MAPK)-inactivation in prostate epithelial cells. These abnormalities underscore a potential fundamental role in prostate development. The trophic factor activity of prosaposin has been localized at a specific amino terminal portion of the molecule that has been the source for a number of biologically active peptides called prosaptides (e.g., TX14A). The expression and function of prosaposin in prostate cancer is not known. METHODS: Using conventional protein expression analysis, immunohistochemical staining, cell proliferation assays, and in vitro invasion assays, we determined the expression of prosaposin and the effect of prosaptide TX14A on cell growth/death protection, motility, invasion, and MAPK signal transduction pathway in prostate cancer cells. RESULTS: We found a higher expression of prosaposin in androgen-independent (AI) prostate cancer cells (PC-3 and DU-145) than in androgen-dependent (AD) LNCaP or normal prostate epithelial cells. Immunohistochemical staining on benign and malignant prostate tissues revealed an intense cytoplasmic anti-prosaposin immunoreactivity in tumor cells, as well as stromal, endothelial, and inflammatory mononuclear cells. The intensity of staining was proportional to the overall Gleason's score. In addition, we demonstrated that TX14A stimulates cell proliferation/survival, migration, and invasion, and activates the Raf-MEK-ERK-RSK-Elk-1 signaling cascade of the MAPK pathway. CONCLUSIONS: These results are suggestive of a potential pleuripotent regulatory function for prosaposin in prostate cancer.

Cell Division↗
PubMed2004

Establishment and characterization of a primary androgen-responsive African-American prostate cancer cell line, E006AA.

BACKGROUND: Establishment of human prostate cancer cell lines is essential to advance our understanding of complex processes associated with the initiation and progression of the disease. In the present study, we report the establishment of a primary African-American prostate cancer cell line (E006AA) as well as its associated stromal cells (S006AA). METHODS: E006AA cell line was established as a spontaneously immortalized cells from a patient with a clinically localized prostate cancer. Extensive characterization of the cells was accomplished using androgen-dependent growth and sensitivity assays, Western analyses, RT-PCR/real-time PCR, cytogenetic analyses, and tumorigenicity in nude mice. RESULTS: E006AA cell line shows androgen-dependent growth, expresses PSA and the androgen receptor (AR) with 26 CAG repeats in exon 1 of AR. Cytogenetic analyses revealed a hypertriploid karyotype with additional numerical gains in chromosomes 5, 6, 8, 10, 17, 20, 21 and a marker chromosome of unknown origin as well as structural abnormalities in chromosomes 4, 5, 8, 9, 11-14, 18, and 20. This cell line is not tumorigenic in nude mice. S006AA cell line, isolated from the same tumor specimen, also expresses AR and shows the morphological characteristics of smooth muscle cells of prostatic stroma. CONCLUSIONS: These cell lines are the first available primary epithelial and stromal cells derived from an African-American patient with organ-confined prostate cancer and in conjunction with other established cell lines, could provide an in vitro model system to investigate early transforming events in prostate cancer.

Black or African American↗
PubMedDate not supplied

Relationships between reverse transcriptase-polymerase chain reaction for prostate specific antigen, survival, and various prognostic laboratory factors in patients with hormone refractory prostate cancer.

The detection of prostate-specific antigen (PSA) mRNA by reverse transcriptase-polymerase chain reaction (RT-PCR) in the bloodstream of prostate cancer patients has been hypothesized as a prognostic marker, however little data are available concerning the association between this molecular marker and other laboratory values of potential importance. In this study, in patients with hormone-refractory prostate cancer (HRPC), relationships were determined between PSA RT-PCR positivity, survival, and various relevant markers including serum PSA, LDH, albumin, alkaline phosphatase and hemoglobin. A total of 19/30 HRPC patients were positive for PSA by RT-PCR. Positivity was significantly linked to serum PSA (P=0.004) and serum alkaline phosphatase (P=0.026) but not to the other laboratory variables. Median survival time for RT-PCR-positive patients was 9 months, compared to 19 months for RT-PCR-negative patients (P=0.035). Median survival time for patients with a hemoglobin>or=11 g/dL was 12 months, compared to 9 months for patients with <11 g/dL (P=0.005). Dichotomized (>or=or or=11 g/dL) remained statistically significant (P=0.019), indicating that RT-PCR had no independent association with survival after controlling for hemoglobin status in this study.

Aged↗