Novel quinazoline HMJ‐30 induces U‐2 OS human osteogenic sarcoma cell apoptosis through induction of oxidative stress and up‐regulation of ATM/p53 signaling pathway

Human osteogenic sarcoma is the most common primary bone tumor. Despite of the success of frontline therapy, about 40% of patients have disease progression and further therapy is palliative and toxic. In this study, we developed a novel quinazoline HMJ‐30 to investigate the cell growth inhibition and apoptotic responses in U‐2 OS human osteogenic sarcoma cells. Our results demonstrated that HMJ‐30 significantly reduced cell viabilities of U‐2 OS, HOS, and 143B cells in a dose‐dependent manner, but it exhibited low cytotoxicity in normal hFOB cells. HMJ‐30 induced DNA damage and apoptosis in U‐2 OS cells as revealed by morphologic changes, comet assay and DAPI staining. Immuno‐staining, colorimetric assays, and Western blotting analyses indicated that activities of caspase‐8, caspase‐9, and caspase‐3 and the levels of Bcl‐2 family‐related proteins (Bcl‐2, Mcl‐1, Bax, BAD, and t‐Bid) were altered in HMJ‐30‐treated U‐2 OS cells. Pretreatment of cells with caspase‐8, ‐9, and ‐3 specific inhibitors significantly reduced the cell growth inhibition. HMJ‐30‐induced apoptosis was mediated through both death‐receptor and mitochondria‐dependent apoptotic pathways in U‐2 OS cells. HMJ‐30 induced early phosphorylation of p53^Ser18 was through the activation of ataxia telangiectasia mutated (ATM) in U‐2 OS cells. The cell growth inhibition by HMJ‐30 was substantially attenuated either by the pre‐incubation of U‐2 OS cells with N‐acetylcysteine (NAC, an antioxidant) and caffeine (an ATM kinase inhibitor) or by p53 knockdown via RNAi. In conclusion, ROS dependent‐ATM/p53 signaling pathway is involved in HMJ‐30‐induced apoptosis in U‐2 OS cells. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 1448–1456, 2011     

Effect of 25-hydroxyvitamin D3 and 1 α,25 dihydroxyvitamin D3 on differentiation and apoptosis of human osteosarcoma cell lines

Osteosarcoma (OS) is a malignant bone tumor predominantly affecting children and adolescents. OS has a 60% survival rate with current treatments; hence, there is a need to identify novel adjuncts to chemotherapeutic regimens. In this pilot study, we investigated the dose‐response to 1α,25‐dihdroxyvitamin D₃ (1,α 25(OH)₂D₃) and 25‐hydroxyvitamin D₃ (25(OH)D₃) by human OS cell lines, SaOS‐2, and 143B. We hypothesized that 1,α 25(OH)₂D₃ and 25(OH)D₃ would stimulate differentiation and induce apoptosis in OS cells in a dose‐dependent manner. Human OS cell lines, SaOS‐2, and 143B, were treated with 1,α 25(OH)₂D₃ or 25(OH)D₃ or an ethanol control, respectively, at concentrations ranging from 1 to 1,000 nM. Ki67 (a marker of cellular proliferation) immunocytochemistry revealed no significant changes in the expression of Ki‐67 or MIB‐1 in 1α,25(OH)₂D₃ or 25(OH)D₃ treated SaOS‐2 or 143B cells. Both control and 1α,25(OH)₂D₃ treated SaOS‐2 and 143B cells expressed vitamin D receptor (VDR). Markers of osteoblastic differentiation in 143B cells and SaOS‐2 cells were induced by both 25(OH)D₃ and 1α,25(OH)₂D, and evident by increases in alkaline phosphatase (ALP) activity, osteocalcin (OCN) mRNA expression, and mineralization of extra‐cellular matrix (ECM) by alizarin red staining. An increasing trend in apoptosis in response to 25(OH)D₃, in both SaOS‐2 and 143B cells was detected by terminal deoxynucleotidyl transferase (TdT)‐mediated dUTP nick end labeling (TUNEL) staining. With 1α,25(OH)₂D₃ treatment, apoptosis was evident at higher concentrations only. These preliminary findings suggest that OS cells express VDR and respond to 25(OH)D₃ and 1α,25(OH)₂D₃ by undergoing differentiation and apoptosis. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:831–844, 2012     

Bone morphogenetic protein‐2 promotes osteosarcoma growth by promoting epithelial‐mesenchymal transition (EMT) through the Wnt/β‐catenin signaling pathway

The correlation between BMP‐2 and osteosarcoma growth has gained increased interest in the recent years, however, there is still no consensus. In this study, we tested the effects of BMP‐2 on osteosarcoma cells through both in vitro and in vivo experiments. The effect of BMP‐2 on the proliferation, migration and invasion of osteosarcoma cells was tested in vitro. Subcutaneous and intratibial tumor models were used for the in vivo experiments in nude mice. The effects of BMP‐2 on EMT of osteosarcoma cells and the Wnt/β‐catenin signaling pathway were also tested using a variety of biochemical methods. In vitro tests did not show a significant effect of BMP‐2 on tumor cell proliferation. However, BMP‐2 increased the mobility of tumor cells and the invasion assay demonstrated that BMP‐2 promoted invasion of osteosarcoma cells in vitro. In vivo animal study showed that BMP‐2 dramatically enhanced tumor growth. We also found that BMP‐2 induced EMT of osteosarcoma cells. The expression levels of Axin2 and Dkk‐1 were both down regulated by BMP‐2 treatment, while β‐catenin, c‐myc and Cyclin‐D1 were all upregulated. The expression of Wnt3α and p‐GSK‐3β were also significantly upregulated indicating that the Wnt/β‐catenin signaling pathway was activated during the EMT of osteosarcoma driven by BMP‐2. From this study, we can conclude that BMP‐2 significantly promotes growth of osteosarcoma cells (143B, MG63), and enhances mobility and invasiveness of tumor cells as demonstrated in vitro. The underlying mechanism might be that BMP‐2 promotes EMT of osteosarcoma through the Wnt/β‐catenin signaling pathway. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1638–1648, 2019.     

Eradication of osteosarcoma by fluorescence‐guided surgery with tumor labeling by a killer‐reporter adenovirus

In a previous study, we developed fluorescence‐guided surgery (FGS) for osteosarcoma using an orthotopic model with 143B human osteosarcoma cells expressing red fluorescent protein (RFP) implanted into the intramedullary cavity of the tibia in nude mice. The FGS‐treated mice had a significantly higher disease‐free survival (DFS) rate than the bright‐light surgery (BLS). However, although FGS significantly reduced the recurrence of the primary tumor, it did not reduce lung metastasis. In the present study, we utilized the OBP‐401 telomerase‐dependent killer‐reporter adenovirus, carrying green fluorescent protein (GFP), to label human osteosarcoma in situ in orthotopic mouse models. OBP‐401‐illuminated human osteosarcoma cell lines, 143B and MNNG/HOS cells in vitro and in vivo. OBP‐401 tumor illumination enabled effective FGS of the 143B‐derived orthotopic mouse model of human osteosarcoma model as well as FGS eradication of residual cancer cells after BLS. OBP‐401‐assisted FGS significantly inhibited local recurrence and lung metastasis after surgery, thereby prolonging DFS and overall survival (OS), achieving a very important improvement of therapeutic outcomes over our previously reported FGS study. These therapeutic benefits of FGS were demonstrated using a clinically‐viable methodology of direct labeling of human osteosarcoma in situ with the OBP‐401 killer‐reporter adenovirus in contrast with previous reports, which used genetically engineered labeled cells or antibody‐based fluorescent labels for FGS. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:836–844, 2016.     

Protein tyrosine phosphatase non-receptor type 12 suppresses tumor progression in osteosarcoma cells

BackgroundProtein tyrosine phosphatase non-receptor 12 (PTPN12) plays a prominent role in various cancers as a tumor suppressor. However, the expression of PTPN12 and its biological functions in osteosarcoma (OS) remains to be determined.MethodsPTPN12 expression in OS was explored in public databases and detected by immunohistochemistry and Western blot. The cell viability was determined by Cell Counting Kit-8 (CCK-8) assay and colony formation. The cell migration and invasion were assessed by the Transwell assay. Flow cytometry analysis was applied to detect cell apoptosis and cell cycle distribution. To investigate the related mechanism, the levels of EGFR and downstream proteins were detected by Western blot.ResultsPTPN12 expression was significantly decreased in OS samples in GEO database and our hospital. OS cell lines in Cancer Cell Line Encyclopedia (CCLE) database and our cultured OS cells also demonstrated low PTPN12 expression. Lentivirus-induced overexpression of PTPN12 significantly inhibited the cell viability, migration and invasion of 143B and U2OS cells. The results of flow cytometry found that PTPN12 overexpression promoted cell apoptosis and induced cell cycle arrest at G1 phase in 143B and U2OS cells. The phosphorylation levels of EGFR and subsequent proteins of the PI3K/AKT and ERK pathways were inactivated as a result of PTPN12 overexpression in OS.ConclusionPTPN12 plays a tumor suppressive role in OS cells. Restoring of PTPN12 activity may provide new insights for the treatment of this disease.     

Benzyl isothiocyanate (BITC) and phenethyl isothiocyanate (PEITC)‐mediated generation of reactive oxygen species causes cell cycle arrest and induces apoptosis via activation of caspase‐3, mitochondria dysfunction and nitric oxide (NO) in human osteogenic sarcoma U‐2 OS cells

Benzyl isothiocyanate (BITC) and phenethyl isothiocyanate (PEITC), a member of the isothiocyanate family, have been shown to exhibit antineoplastic ability against many human cancer cells. In this study, we found that exposure of human osteogenic sarcoma U‐2 OS cells to BITC and PEITC led to induce morphological changes and to decrease the percentage of viable cells in a time‐ and dose‐dependent manner. BITC and PEITC induced cell cycle arrest at G2/M phase at 48 h treatment and inhibited the levels of cell cycle regulatory proteins such as cyclin A and B1 in U‐2 OS cells but promoted the level of Chk1 and p53 that led to G2/M arrest. BITC and PEITC induced a marked increase in apoptosis (DNA fragmentation) and poly(ADP‐ribose)polymerase (PARP) cleavage, which was associated with mitochondrial dysfunction and the activation of caspase‐9 and ‐3. BITC and PEITC also promoted the ROS production in U‐2 OS cells and the N‐acetylcysteine (NAC, an antoxidant agent) was pretreated and then treated with both compounds which led to decrease the levels of ROS and increase the cell viability. Interestingly, BITC and PEITC promoted the levels of NO production and increased the iNOS enzyme. Confocal laser microscope also demonstrated that BITC and PEITC promoted the release of cytochrome c and AIF, suggesting that both compounds induced apoptosis through ROS, caspase‐3 and mitochondrial, and NO signaling pathways. Taken together, these molecular alterations and signaling pathways offer an insight into BITC and PEITC‐caused growth inhibition, G2/M arrest, and apoptotic death of U‐2 OS cells. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 1199–1209, 2011     

The tumor suppressive role of TIMP3 in the human osteosarcoma cells

BackgroundTissue inhibitor of metalloproteinase 3 (TIMP3) regulates a variety of cellular activities such as proliferation, viability, apoptosis, and motility. Functional loss of TIMP3 is reported in several human cancers. However, its role in osteosarcoma (OS) remains largely unclear.MethodsIn this study, we explored the mechanism underlying the modulation of TIMP3 in the growth and aggressiveness of U2OS and 143B human OS cells at both cellular and molecular levels.ResultsOur results show that overexpression of TIMP3 inhibits endogenous MMP activity and represses a series of oncogenic phenotypes of tumor cells independent of MMP inhibition, including reduced proliferation and survival, induced apoptosis, as well as improved sensitivity of tumor cells in response to cisplatin chemotherapy. TIMP3 overexpression also suppresses tumor cell invasion via its MMP inhibitory capacity. Importantly, TIMP3 modulates tumor cell oncogenesis via its induction of PTEN and subsequent inactivation of the PI3K/AKT pathway.ConclusionOur results suggest that TIMP3 is an oncosuppressor in human OS cells. Reactivation of TIMP3 function may be considered as a potential therapy for the treatment of this bone cancer.     

Syk‐Induced Phosphatidylinositol‐3‐Kinase Activation in Epstein–Barr Virus Posttransplant Lymphoproliferative Disorder

Posttransplant lymphoproliferative disorder (PTLD)‐associated Epstein–Barr virus (EBV)+ B cell lymphomas are serious complications of solid organ and bone marrow transplantation. The EBV protein LMP2a, a B cell receptor (BCR) mimic, provides survival signals to virally infected cells through Syk tyrosine kinase. Therefore, we explored whether Syk inhibition is a viable therapeutic strategy for EBV‐associated PTLD. We have shown that R406, the active metabolite of the Syk inhibitor fostamatinib, induces apoptosis and cell cycle arrest while decreasing downstream phosphatidylinositol‐3′‐kinase (PI3K)/Akt signaling in EBV+ B cell lymphoma PTLD lines in vitro. However, Syk inhibition did not inhibit or delay the in vivo growth of solid tumors established from EBV‐infected B cell lines. Instead, we observed tumor growth in adjacent inguinal lymph nodes exclusively in fostamatinib‐treated animals. In contrast, direct inhibition of PI3K/Akt significantly reduced tumor burden in a xenogeneic mouse model of PTLD without evidence of tumor growth in adjacent inguinal lymph nodes. Taken together, our data indicate that Syk activates PI3K/Akt signaling which is required for survival of EBV+ B cell lymphomas. PI3K/Akt signaling may be a promising therapeutic target for PTLD, and other EBV‐associated malignancies.     

Inhibition of mTOR signaling by oleanolic acid contributes to its anti‐tumor activity in osteosarcoma cells

Oleanolic acid (OA), a pentacyclic triterpenoid exhibits potent anti‐tumor activity against many tumor cell lines. But the mechanisms through which OA inhibits osteosarcoma cells are not known. The mammalian target of rapamycin (mTOR) serves as a central regulator of cell growth, proliferation, survival, and metabolism by integrating intracellular and extracellular signals. In this study, we examined effects of OA on proliferation, cell cycle progression, apoptosis in osteosarcoma cells, and involvement of mTOR signaling in this process. OA inhibited cell proliferation and colony formation, induced G1 arrest in osteosarcoma MG63 and Saos‐2 cells dose and time dependently. The protein level of cyclin D1, which plays critical role in G1 to S phase transition and servers as a downstream target of mTOR complex 1 (mTORC1) was down‐regulated by OA. Phosphorylation of p70 ribosomal S6 kinase 1 (p70 S6K1) (T389) and S6 (S235/236), mediators of mTORC1 signaling in controlling protein translation and cell growth, was also inhibited by OA. Furthermore, OA inhibited phosphorylation of Akt, a pro‐survival factor and substrate for mTORC2. Inactivation of Akt correlated with pro‐apoptotic role of OA in osteosarcoma cells, as manifested by an increase in annexin V‐FITC binding, cleavage of poly (ADP‐ribose) polymerase (PARP) and activation of caspases 3. Our results suggest that OA is a promising agent for treatment of osteosarcoma and mTOR signaling may contribute to its anti‐tumor effects on osteosarcoma cells. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:846–852     

阿司匹林抑制核因子-κB增强索拉非尼对肝癌的促凋亡作用

目的 观察合用阿司匹林(Aspirin)与索拉非尼(Sorafenib)对肝癌生长转移的抑制作用和促凋亡作用并探讨其机制.方法 采用人肝癌裸鼠原位模型LCI-D20,分为对照组、Sorafenib 单用组(30 mg/kg灌胃,1d1次)、Sorafenib+ Aspirin合用组、Aspirin单用组(30 mg/kg灌胃,1 d 1 次),治疗4周后观察荷瘤小鼠生存期、肿瘤体积、肺转移,定量比较肿瘤细胞凋亡指数,观察各组荷瘤鼠生存期,检测各组核因子-κB (NF-κB)及IκBα表达.结果 对照组、Sorafenib治疗组、Sorafenib + Aspirin合用组、Aspirin治疗组肿瘤体积分别为(4.76±0.51)、(1.41±0.08)、(0.66 ±0.12)和(4.58±0.47) cm3;肺转移灶数目分别为(189±21)、(96±15)、(30±17)和(92±18)个;中位生存期分别为72、98、112、80 d.肿瘤凋亡指数分别为(2.6±1.1)％、(8.6±3.7)％、(24.3±6.9)％和(6.8±1.5)％;与Sorafenib治疗组比较,Sorafenib+ Aspirin合用明显降低肿瘤体积(P＜0.05)、抑制肺转移灶数目(P＜0.01),延长荷瘤鼠生存期(P＜0.05)和促进肿瘤细胞凋亡(P＜0.05).Sorafenib 在肝癌中具有下调IκBα和上调NF-κB-p65的作用而合用Aspirin可逆转此作用.结论 Aspirin通过抑制NF-κB活化,进一步增强Sorafenib对肝癌凋亡的促进作用及对肝癌生长转移的抑制作用,并延长荷瘤鼠生存期.     

Apoptotic effects of curcumin on human osteosarcoma U2OS cells

Objective: Curcumin, an active ingredient derived from the rhizome of the plant, Curcuma longa, has antioxidant, anti‐inflammatory and anti‐cancer activities. The aims of this study were to examine whether curcumin can induce apoptosis in an osteosarcoma cell line. Methods: Curcumin‐induced apoptosis in human osteosarcoma U2OS cells was investigated using morphological analysis, marked nuclear condensation and fragmentation of chromatin, which were observed by Hoechst 33258 staining and DNA ladder formation. The U2OS cells were treated with or without curcumin. Cell viability was assessed by the 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐Diphenyltetrazolium (MTT) method. Cell‐cycle, apoptosis and apoptosis‐related proteins in U2OS cells were evaluated by flow cytometry and western blotting. Results: Curcumin showed growth inhibitory effects on U2OS cells in a dose‐and time‐dependent manner, inducing significant G1 arrest and apoptosis in U2OS cells. This curcumin‐induced apoptosis in U2OS cells was accompanied by up‐regulation of Bax, Bak, and p‐Bad and down‐regulation of Bcl‐2, but no effect on the levels of Bcl‐X_L or Bad proteins was noted. Moreover, curcumin treatment resulted in a significant reduction of mitochondrial membrane potential and increase in the concentrations of mitochondrial cytochrome C and caspase‐3. Conclusion: Multiple molecular pathways are involved in curcumin‐induced apoptosis of human U2OS cells. These include pro‐and anti‐apoptotic Bcl‐2 family proteins, mitochondrial membrane potential, mitochondrial cytochrome C and caspase‐3.     

Dominant Negative LRP5 Decreases Tumorigenicity and Metastasis of Osteosarcoma in an Animal Model

Osteosarcoma (OS) is a primary malignant bone tumor with a high propensity for local recurrence and distant metastasis. We previously showed a secreted, dominant-negative LRP5 receptor (DNLRP5) suppressed in vitro migration and invasion of the OS cell line SaOS-2. Therefore, we hypothesized DNLRP5 also has in vivo antitumor activity against OS. We used the 143B cell line as a model to study the effect of DNLRP5 by stable transfection. Inhibition of Wnt signaling by DNLRP5 was verified by a reduction in TOPFLASH luciferase activity. In soft agar, DNLRP5-transfected 143B cells formed fewer and smaller colonies than control transfected cells. DNLRP5 transfection reduced in vivo tumor growth of 143B cells in nude mice. DNLRP5 also decreased in vitro cellular motility in a scratch wound assay. In a spontaneous pulmonary metastasis model, DNLRP5 reduced both the size and number of lung metastatic nodules. The reduction in cellular invasiveness by DNLRP5 was associated with decreased expression of matrix metalloproteinase-2, N-cadherin, and Snail. Our data suggest canonical Wnt/LRP5 signaling reflects an important underlying mechanism of OS progression. Therefore, strategies to suppress LRP5-mediated signaling in OS cells may lead to a reduction in local or systemic disease burden.     

Novel quinolone CHM‐1 induces apoptosis and inhibits metastasis in a human osterogenic sarcoma cell line

Novel 2‐phenyl‐4‐quinolone compounds have potent cytotoxic effects on different human cancer cell lines. In this study, we examined anticancer activity and mechanisms of 20‐fluoro‐6,7‐methylenedioxy‐2‐phenyl‐4‐quinolone (CHM‐1) in human osterogenic sarcoma U‐2 OS cells. CHM‐1‐induced apoptosis was determined by flow cytometric analysis, DAPI staining, Comet assay, and caspase inhibitors. CHM‐1‐inhibited cell migration and invasion was assessed by a wound healing assay, gelatin zymography, and a Transwell assay. The mechanisms of CHM‐1 effects on apoptosis and metastasis signaling pathways were studied using Western blotting and gene expression. CHM‐1 induced G2/M arrest and apoptosis at an IC₅₀ (3 µM) in U‐2 OS cells and caspase‐3, ‐8, and ‐9 were activated. Caspase inhibitors increased cell viability after exposure to CHM‐1. CHM‐1‐induced apoptosis was associated with enhanced ROS generation, DNA damage, decreased ΔΨ_m levels, and promotion of mitochondrial cytochrome c release. CHM‐1 stimulated mRNA expression of caspase‐3, ‐8, and ‐9, AIF, and Endo G. In addition, CHM‐1 inhibited cell metastasis at a low concentration (<3 µM). CHM‐1 inhibited the cell metastasis through the inhibition of MMP‐2, ‐7, and ‐9. CHM‐1 also decreased the levels of MAPK signaling pathways before leading to the inhibition of MMPs. In summary, CHM‐1 is a potent inducer of apoptosis, which plays a role in the anticancer activity of CHM‐1. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1637–1644, 2009     

The orally bioavailable met inhibitor PF‐2341066 inhibits osteosarcoma growth and osteolysis/matrix production in a xenograft model

Osteosarcoma (OS) is the most common primary bone tumor in children and adolescents. Ninety percent of patients who present with metastatic and 30% to 40% of patients with nonmetastatic disease experience relapse, creating an urgent need for novel therapeutic strategies. The Met receptor tyrosine kinase and its ligand, hepatocyte growth factor (HGF), are important for mitosis, motility, and cell survival. Upregulation of Met/HGF signaling via receptor overexpression, amplification, or mutation drives the proliferation, invasiveness, and metastasis of a variety of cancer cells, including OS, prompting the development of Met/HGF inhibitors. OS cells depend on Met overexpression because introduction of dominant‐negative Met inhibits in vivo tumorigenicity. Despite the importance of Met/HGF signaling in the development and maintenance of OS, the potential efficacy of pharmacologic Met inhibition in OS has been addressed only in in vitro studies. PF‐2341066 is an orally bioavailable, selective ATP‐competitive Met inhibitor that showed promising results recently in a phase I clinical trial in non–small cell lung cancer (NSCLC) patients. We tested the ability of PF‐2341066 to inhibit malignant properties of osteosarcoma cells in vitro and orthotopic xenograft growth in vivo. In vitro, PF‐2341066 inhibited osteosarcoma behavior associated with primary tumor growth (eg, proliferation and survival) as well as metastasis (eg, invasion and clonogenicity). In nude mice treated with PF‐2341066 via oral gavage, the growth and associated osteolysis and extracortical bone matrix formation of osteosarcoma xenografts were inhibited by PF‐2341066. PF‐2341066 may represent an effective new systemic therapy for localized and potentially disseminated osteosarcoma. © 2011 American Society for Bone and Mineral Research.     

Regulation of growth factors in hormone‐ and drug‐resistant prostate cancer cells by synergistic combination of docetaxel and octreotide

OBJECTIVE

To evaluate the effects of combined treatment with docetaxel and octreotide, a somatostatin analogue, on human hormone‐ and drug‐refractory prostate cancer cell lines, PC‐3 and DU‐145, and on some growth factors related to tumour growth and angiogenesis in prostate cancer.

MATERIALS AND METHODS

A cell proliferation assay was used to assess the cytotoxicity of the drugs. To verify apoptosis, both DNA fragmentation (by enzyme‐linked immunosorbent assay) and caspase 3/7 activity were measured. We also investigated the effect of combined docetaxel and octreotide on growth factors secreted from prostate cancer cells using a human growth factor antibody array.

RESULTS

The combination of docetaxel and octreotide resulted in significant synergistic cytotoxic activity and apoptosis, which was dose‐ and time‐dependent. The combined treatment also resulted in significantly less secretion of stem cell factor and platelet‐derived growth factor‐AB in PC‐3 cells, and transforming growth factor‐β and basic fibroblast growth factor in DU‐145 cells, than in untreated controls.

CONCLUSION

Octreotide, a somatostatin analogue, combined with docetaxel might provide a rationale treatment option for hormone‐refractory prostate cancer cells, not only by direct inhibition of cell proliferation but also by inhibiting the secretion of growth factors.