血管内皮生长因子对关节软骨细胞基质金属蛋白酶-13表达的影响

目的 观察血管内皮生长因子(VEGF)对体外培养的关节软骨细胞基质金属蛋白酶-13(MMP-13)表达的影响.方法 体外培养SD乳鼠关节软骨细胞,分为4组,每组加入不同处理因素进行干预,A组:(对照组)不加任何处理因素;B组:10 μg/L VEGF;C组:10 μg/L白细胞介素(IL)-1β;D组:10 μg/L VEGF+ 10 μg/L IL-1β.采用实时荧光定量聚合酶链反应(PCR)检测MMP-13 mRNA的表达,蛋白免疫印迹法检测MMP-13蛋白的表达.结果 B组(0.88±0.47)、C组(3.69 ±0.45)及D组(3.85 ±0.48)的MMP-13 mRNA表达水平均显著高于A组(0.73±0.56),D组软骨细胞MMP-13的mRNA表达水平明显高于B组(P＜0.01)及C组(P＜0.05).与A组(0.36 ±0.17)比较,B组(0.63±0.21)、C组(0.76±0.24)及D组(0.99±0.26)的MMP-13蛋白表达水平显著升高,D组MMP-13的蛋白表达水平明显高于B组(P＜0.05)及C组(P＜0.05).结论 在骨关节炎的发病过程中VEGF可能通过上调软骨细胞MMP-13的表达发挥重要作用.     

1Alpha,25-dihydroxyvitamin D(3) - not just a calciotropic hormone

1Alpha,25-dihydroxyvitamin D(3), the hormonal form of vitamin D(3), is widely appreciated to play a central role in calcium and phosphorous homeostasis. It is becoming increasingly clear, however, that the sterol also plays an important role in the regulation of cellular growth, central nervous system function, and immune responsiveness. In this review, I will highlight some of the mechanisms by which 1alpha,25-dihydroxyvitamin D(3) regulates cellular growth, alters central nervous system function, and immune function.     

Fibroblast growth factor-23 is regulated by 1alpha,25-dihydroxyvitamin D.

Serum FGF-23 regulation was studied in patients with hypoparathyroidism or pseudohypoparathyroidism treated with calcitriol. Serum FGF-23 levels changed in parallel in response to changes in serum 1,25-D, suggesting that FGF-23 may be regulated by 1,25-D. In addition, the phosphaturic effect of FGF-23 may be diminished in the absence of PTH action on the kidney. INTRODUCTION: Fibroblast growth factor (FGF)-23 is a recently described hormone that has been shown to be involved in the regulation of phosphate and vitamin D metabolism. The physiologic role of FGF-23 in mineral metabolism and how serum FGF-23 levels are regulated have yet to be elucidated. Three patients with mineral metabolism defects that allowed for the investigation of the regulation of FGF-23 were studied. MATERIALS AND METHODS: Patient 1 had postsurgical hypoparathyroidism and Munchausen's syndrome and consumed a pharmacologic dose of calcitriol. Patient 2 had postsurgical hypoparathyroidism and fibrous dysplasia of bone. She was treated with increasing doses of calcitriol followed by synthetic PTH(1-34). Patient 3 had pseudohypoparathyroidism type 1B and tertiary hyperparathyroidism. She underwent parathyroidectomy, which was followed by the development of hungry bone syndrome and hypocalcemia, requiring treatment with calcitriol. Serum FGF-23 and serum and urine levels of mineral metabolites were measured in all three patients. RESULTS: Patient 1 had an acute and marked increase in serum FGF-23 (70 to 670 RU/ml; normal range, 18-108 RU/ml) within 24 h in response to high-dose calcitriol administration. Patient 2 showed stepwise increases in serum FGF-23 from 117 to 824 RU/ml in response to increasing serum levels of 1alpha,25-dihydroxyvitamin D (1,25-D). Finally, before parathyroidectomy, while hypercalcemic, euphosphatemic, with low levels of 1,25-D (10 pg/ml; normal range, 22-67 pg/ml), and with very high serum PTH (863.7 pg/ml; normal range, 6.0-40.0 pg/ml), patient 3 had high serum FGF-23 levels (217 RU/ml). After surgery, while hypocalcemic, euphosphatemic, and with high serum levels of serum 1,25-D (140 pg/ml), FGF-23 levels were higher than preoperative levels (305 RU/ml). It seemed that the phosphaturic effect of FGF-23 was diminished in the absence of PTH or a PTH effect. CONCLUSIONS: Serum FGF-23 may be regulated by serum 1,25-D, and its phosphaturic effect may be less in the absence of PTH.     

1 Alpha,25-dihydroxyvitamin D3 rapidly increases cytosolic calcium in clonal rat osteosarcoma cells lacking the vitamin D receptor.

1 alpha,25-Dihydroxyvitamin D3 [1 alpha,25-(OH)2D3] rapidly increases cytosolic calcium in a variety of cell types. Although these rapid effects do not appear to directly involve genome activation, the requirement for the classic vitamin D receptor is unclear. Clonal rat osteosarcoma cells, ROS 17/2.8, respond to 1 alpha,25-(OH)2D3 with an increase in osteocalcin message but ROS 24/1 cells do not. The lack of the receptor for vitamin D in the ROS 24/1 cells has been confirmed by the absence of any detectable vitamin D-receptor complex binding to the vitamin D-responsive element (VDRE) of the osteocalcin gene and the absence of vitamin D receptor mRNA in the cells. Quin-2-loaded ROS 17/2.8 and ROS 24/1 cells were treated with 1 alpha,25-(OH)2D3 in the presence and absence of extracellular calcium and with the inactive epimer, 1 beta,25-dihydroxyvitamin D3 [1 beta,25-(OH)2D3]. The 1 alpha,25-(OH)2D3 increased cytosolic calcium in the ROS 17/2.8 and 24/1 cells after 5 minutes in a dose-responsive manner and in the presence and absence of extracellular calcium. Pretreatment of both cell lines with 1 beta,25-(OH)2D3 for 30 s blocked the hormone-induced rise in cytosolic calcium. The rapid effects of 1 alpha,25-(OH)2D3 on ROS cells with and without the vitamin D receptor and the ability of the inactive epimer to inhibit these effects indicate that the signaling system mediating the hormone's rapid actions is not the classic vitamin D receptor.     

Pigment epithelium-derived factor expression is down-regulated in bladder tumors and correlates with vascular endothelial growth factor and matrix metalloproteinase-9

Growth of solid tumor depends on angiogenesis, a process regulated by the balance of pro- and anti-angiogenic factors. We investigated the expression of anti-angiogenic factor pigment epithelium-derived factor (PEDF) and proangiogenic factors vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9) with immunohistochemistry in 64 bladder tumor samples and 23 normal controls. Compared with normal urothelium, we identified decreased PEDF expression (P = 0.000) whereas increased expression of VEGF (P = 0.000) and MMP-9 (P = 0.000) in tumorous tissue as well as in papillary urothelial neoplasm of low malignant potential (PUNLMP) (P = 0.009 and P = 0.000 accordingly) but MMP-9 (P = 0.704). Decreased PEDF expression was revealed with higher tumor grade (P = 0.014) but stage (P = 0.687). There was no age or gender preference in PEDF, VEGF or MMP-9 expression. Negative correlation of expression in tumorous and cancerous tissue regarding PEDF and VEGF (P = 0.000, r = −0.56, and P = 0.000, r = −0.50, respectively), PEDF and MMP-9 (P = 0.002, r = −0.39, and P = 0.032, r = −0.30, respectively) was identified. There was a negative correlation of expression between PEDF and VEGF (P = 0.016, r = −0.677) and no correlation between PEDF and MMP-9 (P = 0.147, r = −0.45) in PUNLMP. Decreased PEDF and increased VEGF and MMP-9 expression may play considerable roles in differentiation and invasion of bladder tumor.     

1 alpha,25-dihydroxyvitamin D3-induced increments in hepatocyte cytosolic calcium and lysophosphatidylinositol: inhibition by pertussis toxin and 1 beta,25-dihydroxyvitamin D3

1 alpha,25-Dihydroxyvitamin D3 rapidly increases cytosolic calcium and alters membrane phospholipid metabolism in hepatocytes. To define the causal relationship between these events, we examined the effects of 1 alpha,25-dihydroxyvitamin D3 on 32P-labeled lysophosphatidylinositol levels and cytosolic calcium as affected by pertussis toxin and 1 beta,25-dihydroxyvitamin D3, the biologically inactive analog. 32P-labeled lysophosphatidylinositol was determined by two-dimensional thin-layer chromatography. Cytosolic calcium was measured in cells loaded with quin-2AM. Within 5 min, 1 alpha,25-dihydroxyvitamin D3 increased hepatocyte cytosolic calcium by 31% (p less than 0.05) and 32P-labeled lysophosphatidylinositol by 38% (p less than 0.05). Pertussis toxin inhibited the hormone-induced rise in cytosolic calcium but not the increase in 32P-labeled lysophosphatidylinositol. Exposure to exogenous lysophosphatidylinositol for 5 min increased cytosolic calcium by 40% (p less than 0.05), an effect that was also inhibited by pertussis toxin. 1 beta,25-Dihydroxyvitamin D3 had no effect on either hepatocyte cytosolic calcium or 32P-labeled lysophosphatidylinositol but prevented the 1 alpha,25-dihydroxyvitamin D3-induced increments. The results suggest that a G protein sensitive to pertussis toxin is required for the transduction of the lysophosphatidylinositol signal but not the generation of the signal. The ability of 1 beta,25-dihydroxyvitamin D3 to inhibit the 1 alpha,25-dihydroxyvitamin D3-induced changes in phospholipids suggests that the epimer may compete with 1 alpha,25-dihydroxyvitamin D3 for an initiating receptor.     

胆囊癌组织中COX-2、VEGF的表达与血管形成的相关性及预后意义

目的研究原发性胆囊癌组织中VEGF(vascular endothelial growth factor,血管内皮生长因子)、COX-2的表达与血管形成的关系及预后意义。方法应用免疫组织化学SP法对64例胆囊癌组织COX-2、VEGF表达和MVC进行检测。结果 COX-2和VEGF阳性表达率分别为72％和 55％。64例胆囊癌MVC平均为(57±14)个／HP。MVC与胆囊癌分化程度、Nevin分期和淋巴结转移密切相关(t=2．948,t=5．102,t=7．329,P<0．05)。VEGF在中低分化型和有淋巴结转移胆囊癌中的表达显著高于高分化型和淋巴结未转移者(x2=5．752,x2=10．093,P<0．05)。COX-2在Nevin分期S4-S5和有淋巴结转移的胆囊癌中的表达显著高于分期为S1-S3和淋巴结未转移者(x2=6．886, x2=12．882,P<0．05)。COX-2和VEGF表达与MVC值之间具有显著相关性(r=0．268,x2=4．608, P<0．05,t=5．424,P<0．05)。COX-2、VEGF的表达与患者的预后有关(x2=8．276,x2=6．656, P<0．05),结论 COX-2、VEGF和MVC是反映胆囊癌生物学行为的重要参数。COX-2高表达与胆囊癌的血管生成密切相关,其可能机制之一是促进VEGF的表达。     

胆管癌微血管计数和VEGF及MMP2的表达及其意义

目的：探讨胆管癌组织中微血管密度（MVD）、血管内皮生长因子（VEGF）、基质金属蛋白酶2（MMP2）与胆管癌转移、预后的关系。方法：应用免疫组化的方法检测45例胆管癌及8例正常肝外胆管组织的MVD，VEGF和MMP2表达。结果：（1）胆管癌组织MVD值，VEGF，MMP2阳性表达率显著高于正常胆管组织（P＜0．05）；（2）胆管癌组织MVD，VEGF，MMP2的表达强度与胆管癌的病理分期、淋巴结转移有显著相关性（P＜0．05）；结论：MVD增高提示胆管癌转移侵袭潜能增加，VEGF，MMP2可能作为预测胆管癌转移的指标。     

1alpha,25-dihydroxyvitamin D3 induced growth inhibition of PC-3 prostate cancer cells requires an active transforming growth factor beta signaling pathway

BACKGROUND: Prostate cancer growth inhibition by 1alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3) is best characterized in the androgen dependent LNCaP cell line, where treatment with this hormone causes cell cycle arrest and apoptosis. 1,25(OH)2D3 also inhibits the growth of PC-3 prostate cancer cells, but not through the induction of G1 arrest or apoptosis. In this study, we have sought to elucidate the mechanism/s involved in PC-3 cell growth inhibition by 1,25(OH)2D3. EXPERIMENTAL METHODS: We determined the effect of transforming growth factor beta (TGFbeta) blocking antibodies on 1,25(OH)2D3 mediated growth inhibition of PC-3 cells. In addition, we also studied the effects of 1,25(OH)2D3 on TGFbeta signaling and receptor expression. Finally, we assessed the role of TGFbeta signaling in the induction of the growth inhibitory protein, insulin like growth factor binding protein 3 (IGFBP-3), by 1,25(OH)2D3. RESULTS: We find that 1,25(OH)2D3 action in PC-3 cells is mediated through at least two distinct pathways, the TGFbeta pathway and the IGFBP-3 pathway. We show that 1,25(OH)2D3 treatment elevates TGFbeta production and signaling, as well as receptor levels, in PC-3 cells. Further, using a blocking antibody against TGFbeta substantially reduces 1,25(OH)2D3 mediated growth inhibition without affecting IGFBP-3 induction, suggesting that IGFBP-3, alone, is insufficient to inhibit the growth of PC-3 cells.     

24,25-dihydroxyvitamin D3 suppresses the rapid actions of 1, 25-dihydroxyvitamin D3 and parathyroid hormone on calcium transport in chick intestine.

Studies were undertaken to determine whether 24,25-dihydroxyvitamin D3 (24,25(OH)2D3) modulates the rapid effects of 1, 25-dihydroxyvitamin D3 (1,25(OH)2D3) and parathyroid hormone (PTH) on calcium transport in the perfused chick intestine. Perfusion with control media resulted in a transport ratio (treated/average basal) of 1.07 +/- 0.06 at t = 40 minutes, while perfusion with 65, 130, 300, or 650 pM 1,25(OH)2D3 yielded ratios of 1.92 +/- 0.23, 2.6 +/- 0.4, 2.8 +/- 0.08, and 3.34 +/- 0.37, respectively. Simultaneous perfusion with each of these doses and 6.5 nM 24,25(OH)2D3 reduced treated/average basal ratios to approximately 1.4 after 40 minutes of perfusion. Vascular perfusion with 65 pM bovine PTH [bPTH(1-34)] stimulated intestinal calcium transport ratios to 3.0 +/- 0.5 after 40 minutes, while the inclusion of 6.5 nM 24,25(OH)2D3 reduced ratios at this time point to 0.56 +/- 0.19. To investigate the effect of these agents on signal transduction, isolated intestinal cells were monitored for intracellular calcium changes using the indicator dye fura-2. After establishing a stable baseline, addition of 130 pM 1,25(OH)2D3 induced rapid calcium oscillations. Intestinal cells exposed to 6.5 nM 24,25(OH)2D3 also exhibited rapid oscillations in fluorescence, which were not further altered by subsequent addition of 1,25(OH)2D3. Incubation of isolated cells with 130 pM 1,25(OH)2D3 was found to increase protein kinase C (PKC) activity within 5 minutes, and protein kinase A (PKA) activity within 7 minutes. Exposure of cells to 65 pM bPTH(1-34) had minimal effect on PKC activity, but resulted in pronounced increases in PKA activity. Stimulation of protein kinases by either secosteroid or peptide hormone was inhibited in the presence of 6.5 nM 24,25(OH)2D3. It is concluded that 24,25(OH)2D3 may exert endocrine actions on intestine.     

Vascular endothelial growth factor C and vascular endothelial growth factor receptor 3 expression in squamous cell carcinomas of the head and neck

BACKGROUND AND METHODS: VEGF proteins and their receptors are involved in tumor vessel neoformation. The third VEGF receptor, VEGFR3 (flt-4) is important during both blood vessel development and lymphatic vessel formation. Because HNSCC preferentially metastasizes to regional lymph nodes, we investigated the expression of VEGFR3 and its ligand VEGF-C in head and neck squamous cell carcinomas by semiquantitative RT-PCR (4 HNSCC cells lines and 6 HNSCC specimens) and by immunohistochemistry (18 HNSCC specimens). VEGFR3 protein expression was confirmed by Western blotting in four HNSCC cell lines and six HNSCC specimens. RESULTS: Semiquantitative mRNA analysis showed VEGF-C mRNA expression in three (SCC9, SCC25, LFFR) of four HNSCC cell lines and all six HNSCC specimens. VEGFR3 mRNA was found in two HNSCC cell lines (JPPA and SCC25) and only weakly detected in the other two HNSCC cell lines (SCC9 and LFFR). High amounts of VEGFR3 mRNA were shown in all six patients' tumor specimens. VEGFR3 Western blot analysis yielded a distinct band at the predicted size of 210 kD in JPPA and SCC9 and hardly detectable bands in SCC25 and LFFR cell lines. All six HNSCC specimens displayed strong VEGFR3 protein bands. Immunohistochemistry in 18 HNSCC specimens assigned strong to mediate VEGF-C IR and minor VEGFR3 IR to tumor cells and strong VEGF-C and VEGFR3 IR to tumor surrounding vessels. In addition, intense VEGF-C immunostaining was observed on perivascular and mononuclear cells in the tumor surrounding stroma. Subtyping of VEGFR3+ microvascular tumor vessels revealed partially double immunolabeling with CD34 and flk-1, indicating a common origin of blood and lymphatic vessels. The expression of VEGF-C on tumor cells could be correlated with recurrences, and larger primary tumors had more VEGF-C-positive vessels. CONCLUSIONS: The broad expression of VEGF C and VEGFR3 in HNSCC suggests involvement in tumor lymph angiogenesis and vascular angiogenesis, promoting tumor growth and propagation of cancer cells. This implies that inhibitors of lymph angiogenesis could become effective therapeutic options similar to classical angiogenesis inhibitors.     

PRS-CTGF-siRNA对TGF-β1诱导的人腹膜间皮细胞细胞外基质及VEGF表达的影响

目的 观察pRetro-Super(PRS)反转录病毒载体介导的表达人结缔组织生长因子(CTGF)小分子干扰RNA(siRNA)对体外培养的人腹膜间皮细胞(HPMC) 细胞外基质和血管内皮生长因子(VEGF)表达的影响。 方法 根据siRNA靶序列要求及PRS反转录病毒载体特点分别设计4 对寡核苷酸，构建表达人CTGF基因siRNA 的PRS-CTGF-siRNA1～4重组反转录病毒载体。以脂质体2000将重组反转录病毒载体转染PT67包装细胞，继而感染HPMC。采用RT-PCR法检测mRNA表达及Western印迹法检测蛋白质表达。 结果 5 μg/L外源性转化生长因子β1（TGF-β1）刺激可诱导HPMC表达CTGF、纤连蛋白（FN）、I型胶原（Col I）、层粘连蛋白（LN）和VEGF明显增高； 而PRS-CTGF-siRNA 1～4组与TGF-β1刺激组比较，HPMC细胞内CTGF、FN、Col I、LN mRNA和蛋白表达和VEGF mRNA表达明显较低（P < 0.01），各干扰组对CTGF mRNA抑制率分别为 69.3％、22.2%、27.4%和38.8%，其中以PRS-CTGF-siRNA 1组最为明显；同时PRS-CTGF-siRNA 1组相对于TGF-β1刺激组，VEGF蛋白表达也明显较低（P < 0.01）；而PRS空载体组与TGF-β1刺激组比较，差异无统计学意义（P ＞ 0.05）。 结论 PRS-CTGF-siRNA重组反转录病毒载体可明显抑制TGF-β1诱导的细胞外基质及VEGF表达的增加。     

Inhibitory effect of 1 alpha,25-dihydroxyvitamin D3 on the growth of the renal carcinoma cell line

We studied the effect of vitamin D compounds on the growth of the human renal carcinoma cell line (KU-2) and discovered a receptor protein specific for the active form of vitamin D3, 1 alpha,25-dihydroxyvitamin D3. The KU-2 cell line was established from a pulmonary metastasis of renal cell carcinoma in a patient with hyperhemoglobinemia. The cells were tumorigenic in nude mice and clonogenic in a soft agar culture. Vitamin D3 derivatives suppressed proliferation of KU-2 cells in a monolayer culture and also clonogenicity in a soft agar culture dose-dependently. Of the vitamin D3 derivatives tested, 1 alpha,25-dihydroxyvitamin D3 was the most potent in inhibiting cell growth, followed successively by 1 alpha,24R,25-trihydroxyvitamin D3, 25-hydroxyvitamin D3, 1 alpha-hydroxyvitamin D3 and 24R,25-dihydroxyvitamin D3 in that order. Analysis of the cell cycle phase of treated and non-treated KU-2 cells revealed that the action of 1 alpha,25-dihydroxyvitamin D3 was not phase-specific but simply extended the doubling time of the cells. Radioreceptor assay and sucrose density gradient analysis of the cytosol showed that KU-2 cells contained a 3.2S receptor protein to which 1 alpha,25-dihydroxyvitamin D3 was specifically bound (Kd = 20.8 +/- 4.8 pM, Nmax = 87 +/- 24 fmole/mg protein, 4000 molecules/cell). On the other hand, the equilibrium dissociation constant of internalization of 1 alpha,25-dihydroxyvitamin D3 (Kint) by intact KU-2 cells was 1.2 nM and the internalizing capacity was 33 fmole/8 X 10(6) cells (2500 molecules/cell) in the 10% serum medium, which was the same as that used in the growth study.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of 1 alpha-hydroxyvitamin D3 and 24R,25-dihydroxyvitamin D3 on bone remodeling

The present study was undertaken to evaluate the effects of 1 alpha-hydroxyvitamin D3 and 24R,25-dihydroxyvitamin D3 on bone remodeling in dogs with osteomalacia induced by vitamin D depletion. To assess the rates of skeletal remodeling, intravital tetracycline labeling and morphometry of surface pattern were employed. Either vitamin D3 derivative accelerated the appositional growth rate, increased the percentage of osteoid seams labeled, and decreased the number, width, and perimeter of new osteoid seams. But the derivatives differed in bone resorbing activity: 1 alpha-hydroxyvitamin D3 increased the number and perimeter of resorption sites whereas 24R,25-dihydroxyvitamin D3 decreased them. Thus the results show that the former is a better bone remodeler while the latter may be useful in treating osteoporosis.     

Evaluation of vascular endothelial growth factor blockade and matrix metalloproteinase inhibition as a combination therapy for experimental human pancreatic cancer

Blockade of vascular endothelial growth factor (VEGF) and inhibition of matrix metalloproteinases (MMP) are promising therapies for cancer. This study assessed the effects of a neutralizing anti-VEGF antibody (A4.6.1) and an MMP inhibitor (BB-94) on pancreatic cancer (PaCa) in vivo. Five million cells of two human PaCa cell lines (AsPC-1 and HPAF-2) were injected subcutaneously into nude mice; 1 mm³ fragments of the resulting tumors were implanted into the pancreas of other mice. Animals were randomized into a control group and three treatment groups: A4.6.1 (100 Μg intraperitoneally twice weekly); BB-94 (50 mg/kg every other day); and combination (A4.6.1 plus BB-94). Treatment was started after 3 days and continued for 14 weeks. Tumor volume, local and distant spread (score), and ascites were determined at autopsy. Microvessel density as a parameter of neoangiogenesis was analyzed in CD31-stained tumor sections. Both monotherapies reduced tumor volume (HPAF-2: −89% by A4.6.1 and −75% by BB-94; AsPC-1: −48% by A4.6.1 and −72% by BB-94), spread (HPAF-2: -−76% by A4.6.1 and -58% by BB-94; AsPC-1: −32% by A4.6.1 and −54% by BB-94), and microvessel density (HPAF-2: −75% by A4.6.1 and −30% by BB-94; AsPC-1: −59% by A4.6.1 and −30% by BB-94), resulting in a tendency toward increased survival (HPAF-2: 8 of 8 animals by A4.6.1 or BB-94 vs. 4 of 8; AsPC-1: 3 of 8 by A4.6.1, 4 of 8 by BB-94 vs. 1 of 8). Combination therapy yielded additional effects in the HPAF-2 group with regard to tumor volume (−95%) and development of ascites (0 of 8 vs. 2 of 8 by A4.6.1 or BB-94 vs. 5 of 8 control mice). Both VEGF blockade and MMP inhibition reduce primary tumor size, metastasis, and angiogenesis, thereby increasing survival in experimental pancreatic cancer. Combination treatment results in additive effects in moderately differentiated HPAF-2 tumors. Presented at the Forty-Third Annual Meeting of The Society for Surgery of the Alimentary Tract, San Francisco, California, May 19–22, 2002 (oral presentation). Supported by the R.S. Hirshberg Foundation and the Deutsche Forschungsgemeinschaft (grant HO 1843-1).     

Expression patterns of matrix metalloproteinases and vascular endothelial growth factor during epiphyseal ossification.

In situ hybridization studies allowed for the localization of three MMPs and the angiogenic factor VEGF during secondary ossification. MMPs were widely expressed during ossification of the secondary center, whereas expression of VEGF was restricted to later stages. INTRODUCTION: The spatiotemporal expression patterns of the matrix metalloproteinases gelatinase-B (MMP-9), collagenase-3 (MMP-13), and membrane-type 1 metalloproteinase (MMP-14) and the angiogenic peptide vascular endothelial growth factor (VEGF) were studied during development of the proximal epiphysis of the rat tibia. MATERIALS AND METHODS: Cell expression was analyzed by in situ hybridization. Studies on osteoclastic activity, matrix mineralization, cell proliferation, and vascular progression were also performed. RESULTS: MMP-9, MMP-13, and MMP-14 were expressed in discrete perichondrial cells that gave way to sites of intrachondral canal formation. High expression levels for the three MMPs were found at the blind ends of advancing intrachondral canals and at the expanding borders of the marrow space. Signals for MMP-9 and MMP-13 were in close proximity but did not overlap, whereas MMP-14 was expressed in both MMP-9+ and MMP-13+ cells. VEGF was not expressed during formation of intrachondral vascular canals but was observed in hypertrophic chondrocytes during formation of the bone marrow cavity. CONCLUSIONS: Expression of MMPs and VEGF are constant events during development of the secondary ossification center. We propose that MMPs are involved in targeting proteolytic activity during epiphyseal development. VEGF is not expressed during early formation of vascular canals, but it may have a role in the formation of the bone marrow cavity.     

Role of insulin-like growth factor binding proteins in 1alpha,25-dihydroxyvitamin D(3)-induced growth inhibition of human prostate cancer cells

BACKGROUND: The mechanisms underlying 1alpha,25-dihydroxyvitamin D(3) (1,25D)-induced growth inhibition of human prostate cancer cells have not been fully elucidated. To determine whether alterations in the insulin-like growth factor (IGF) signaling axis are associated with 1,25D-induced growth inhibition, we examined the ability of 1,25D to regulate expression of IGF binding proteins (IGFBPs) in human prostate cancer cell lines. METHODS: Northern and Western blot analyses were used to detect 1,25D-induced alterations in IGFBP expression. Additional in vitro studies were performed to determine the role of IGFBP-3 in 1,25D-induced growth inhibition. RESULTS: 1,25D decreased mRNA levels of the growth stimulatory IGFBP-2 and induced IGFBP-3 mRNA in LNCaP and C4-2 cells. 1,25D treatment also increased secreted IGFBP-3 protein levels in prostate cancer cell lines sensitive to 1,25D growth inhibition but had little effect on IGFBP-3 expression in 1,25D-resistant DU145 cells. However, recombinant IGFBP-3 had only a minor effect on LNCaP cell growth in the presence of serum. Furthermore, siRNA duplexes that reduced IGFBP-3 expression did not alter 1,25D growth inhibition in either LNCaP or PC-3 cell lines grown in serum-containing media. CONCLUSIONS: Our studies indicate 1,25D-induced up-regulation of IGFBP-3 is not required for the growth inhibitory effects of 1,25D in prostate cancer cells grown in serum-containing media.