Targeted gene silencing using a follicle-stimulating hormone peptide-conjugated nanoparticle system improves its specificity and efficacy in ovarian clear cell carcinoma in vitro
© Hong et al.; licensee BioMed Central Ltd. 2013
Received: 12 September 2013
Accepted: 18 November 2013
Published: 20 November 2013
RNA interference technology has shown high therapeutic potential for cancer treatment. However, serum instability, poor tissue permeability and non-specific uptake of short interfering RNA (siRNA) limit its administration in vivo. To overcome these limitations and improve the specificity for ovarian cancer, we developed a targeted nanoparticle delivery system for siRNA. This system included follicle-stimulating hormone (FSH) β 33–53 peptide as a targeting moiety that specifically recognized FSH receptor (FSHR) expressed on ovarian cancer cells. Growth regulated oncogene α (gro-α) has been reported to be involved in ovarian cancer development and progression. Thus, siRNA targeted to gro-α was used as an antitumor drug in this delivery system.
FSH β 33–53 peptide-conjugated gro-α siRNA-loaded polyethylene glycol (PEG)-polyethylenimine (PEI) nanoparticles (FSH33-G-NP) were prepared and characterized by gel retardation assay and transmission electron microscopy. Particle size and zeta potential were determined. Expression of gro-α mRNA and protein was detected by real-time quantitative RT-PCR, immunocytochemistry and enzyme-linked immunosorbent assay. The proliferation, migration and invasion of the ovarian clear cell carcinoma cell line ES-2 were evaluated by cell counting kit-8 assay, cell scratch assay and transwell migration assay.
A siRNA sequence that is effective in silencing gro-α expression was obtained and loaded into the targeted delivery system. Compared with gro-α siRNA-loaded nanoparticles without FSH peptide modification (G-NP), FSH33-G-NP significantly down-regulated gro-α expression in ES-2 cells at mRNA and protein levels. Consequently, the aggressive biological behaviors of ES-2 cells, including proliferation, migration and invasion, were suppressed after silencing gro-α expression, and the addition of the FSH β 33–53 peptide enhanced the suppressive effects.
This study indicated that a FSHR-mediated delivery system could mediate the highly selective delivery of siRNA into ovarian cancer cells and that silencing gro-α expression could be a potential choice for ovarian cancer treatment.
KeywordsOvarian carcinoma Targeted therapy Follicle-stimulating hormone Growth-regulated oncogene α Short interfering RNA Nanoparticle
Ovarian cancer, known as a “silent killer”, is the most fatal of all female reproductive system malignant tumors due to the lack of effective early diagnostic methods and because most late-stage patients do not respond to routine treatments . When compared with other epithelial ovarian cancers, ovarian clear cell carcinoma is more easily resistant to conventional platinum-based chemotherapy and has a worse prognosis . Therefore, more effective treatment methods are urgently needed.
Short interfering RNA (siRNA) has been considered as a useful tool to silence genes. Recently, RNA interference (RNAi) technology has shown high therapeutic potential for cancer treatment . However, siRNA administration in vivo is limited because of its serum instability, poor cellular membrane permeability and non-specific uptake . Delivery systems including liposomes, nanoparticles (NPs), chemical modification and viral vectors have been used to overcome these limitations [5, 6]. To improve the specificity and selectivity for tumor tissue, specific ligands including monoclonal antibodies, peptides and small molecules have often been introduced into the delivery systems .
In our previous study, we showed that follicle-stimulating hormone (FSH) β 33–53 peptide and FSH β 81–95 peptide are able to facilitate the access of paclitaxel-loaded NPs specifically into FSH receptor (FSHR)-positive ovarian tissues. In addition, paclitaxel NPs modified with FSH β 33–53 peptide or FSH β 81–95 peptide showed a higher antitumor efficacy against ovarian cancer and produced fewer adverse side effects [8, 9]. FSHR-mediated targeted therapeutics show high potential in ovarian cancer therapy because of limited FSHR distribution in the human reproductive system. To specifically deliver genetic drugs including siRNA into ovarian cancer tissues, we recently developed a novel gene delivery system, polyethylene glycol (PEG)-polyethylenimine (PEI) complex modified with FSH β 33–53 peptide, to deliver siRNA carried by NPs into FSHR-positive cells .
Growth regulated oncogene α (gro-α), also called chemokine (C-X-C motif) ligand 1, is secreted by macrophage, neutrophil and epithelial cells, and gro-α plays a role in angiogenesis, inflammation and wound healing . There is high level of gro-α expression in ulcerative colitis, colon adenomas, colon cancer, melanoma, breast cancer, bladder cancer and ovarian cancer [12–17]. Gro-α overexpression could promote the proliferation, invasion and metastasis of tumor cells [18, 19]. Recent studies have shown that tissues and sera from patients with ovarian cancer have high levels of gro-α expression, while normal ovarian epithelial cells and fibroblasts have lower gro-α expression . High levels of gro-α in stromal cells promote the senescence of fibroblasts and consequently cause the malignant transformation of ovarian epithelial cells [20, 21]. Moreover, gro-α over expression can promote the development and progression of ovarian cancer and the formation of endometriosis . Thus, the down-regulation of gro-α might suppress the aggressive biological behaviors of ovarian cancer cells.
In this study, to overcome the limitations of siRNA administration in vivo and improve the specificity for ovarian cancer, we prepared FSH β 33–53 peptide-conjugated gro-α siRNA-loaded nanoparticle. FSH β 33–53 peptide was used as an ovarian cancer targeting moiety, and siRNA targeted to gro-α was used as a therapeutic drug. The specific down-regulation of gro-α and the suppression of aggressive biological behaviors of ovarian clear cell carcinoma cells were further evaluated after treatment.
FSH β 33–53 peptide (YTRDLVYKDPARPKIQKTCTF) was synthesized by China Peptides Co., Ltd. (Shanghai, China). Branched PEI (MW 25,000 Da) was purchased from Sigma Aldrich Co. (St. Louis, USA). Maleimide-conjugated PEG (Mal-PEG) was purchased from Nektar Therapeutics (San Carlos, CA). The siSTABLE siRNA sequences targeted to gro-α mRNA and negative control siRNA (siRNA-NC) were synthesized by Thermo Fisher Scientific (Shanghai, China). The sequences were as follows: 5′-GCUGGCGGAUCCAAGCAAA-3′ (siRNA-1), 5′-TTTCCGCCCATTCTTGAGTGT-3′ (siRNA-2), 5′-CAAGCTTTCCGCCCATTCTTG-3′ (siRNA-3) and 5′-TATAATAGGACAGTGTGCAGG-3′ (siRNA-4). The siRNA expression plasmid, pcDNA™6.2-GW/EmGFP-miR (5,699 bp), was obtained from Invitrogen Trading Co., Ltd. (Shanghai, China). DharmaFECT transfection reagent was obtained from Thermo Fisher Scientific (Shanghai, China). FSHR antibody and gro-α antibody were purchased from Abcam Ltd. (San Francisco, USA). The gro-α ELISA kit was purchased from R&D Systems Inc. (Minneapolis, USA). The cDNA synthesis kit was purchased from Fermentas Inc. (Canada). The Cell Counting Kit-8 (CCK-8) was purchased from Dojindo Laboratories (Kumamoto, Japan).
The human serous ovarian carcinoma cell line SKOV-3 and human ovarian clear cell carcinoma cell line ES-2 were purchased from the Cell Bank of the Chinese Academy of Science (Shanghai, China). SKOV-3 cells were grown in McCoy”s 5A Medium, and ES-2 cells were grown in RPMI 1640 medium. Medium was supplemented with 10% fetal bovine serum, and cells were cultured at 37°C in a 5% CO2 environment.
To screen for an effective siRNA sequence targeting gro-α, ES-2 cells were seeded in 24-well plates at a density of 1 × 105 cells per well and cultured to reach 60% confluence. Then, 1.5 μg of siRNA-1, siRNA-2, siRNA-3, siRNA-4 or siRNA-NC along with DharmaFECT transfection reagent were diluted and added to the corresponding wells according to the manufacturer’s instructions. After incubation for 4 h, the medium containing siRNA was replaced with fresh medium containing 10% fetal bovine serum. After 24 h or 48 h, the cell lysates were collected for reverse transcription-polymerase chain reaction (RT-PCR), and cell supernatants were collected for enzyme-linked immunosorbent assay (ELISA).
To detect the suppression efficiency of gro-α by nanoparticle complexes, the same procedures were performed as above, except that the cells were incubated with serum-free medium containing 1.5 μg of gro-α siRNA-loaded nanoparticles without the transfection reagents.
Preparation and characterization of FSH β 33–53 peptide-conjugated gro-α siRNA-loaded NPs
The gro-α siRNA4-loaded nanoparticle complexes with or without FSH β 33–53 peptide modification were prepared as previously described . Briefly, the solutions containing FSH β 33–53 peptide and Mal-PEG were mixed and magnetically stirred for 6 h at room temperature. Then, 46.5 mg of this product, FSH33-PEG, was added to 10 mL of 2 mg/mL PEI solution and magnetically stirred for 24 h at room temperature. The product, FSH33-PEG-PEI, was dissolved and added into the same volume of plasmid DNA (pDNA) (containing gro-α siRNA4) solution drop by drop with magnetically stirring. The molar ratio of nitrogen from PEI to phosphate from pDNA (N/P) was 25. The final complex, FSH33-PEG-PEI-pDNA, was freeze-dried. The PEG-PEI-pDNA complex without FSH peptide was prepared by the same method.
The encapsulating efficiencies of the complexes were determined by gel retardation assay. The morphologies of the complexes were examined using the Joel Jem 2100 F transmission electron microscope (JEOL Ltd., Japan). Particle size and zeta potential were determined using the Malvern Zetasizer autosize 4700 (Malvern Instruments Ltd., Malvern, UK).
To detect the expression of FSHR and gro-α, immunocytochemistry was used. After fixation with 4% paraformaldehyde, cells were incubated with FSHR antibody (1:500) or gro-α antibody (1:500) overnight, and then incubated with peroxidase-conjugated anti-rabbit IgG for 30 min. The staining reaction was performed with diaminobenzidine. The cells were counter-stained with hematoxylin to detect nuclei, and imaged by light microscopy (Olympus, Tokyo, Japan).
Reverse transcription-polymerase chain reaction
RNA was isolated from cells, and 1 μg of total RNA was reverse-transcribed using a cDNA synthesis kit according to the manufacturer’s instructions. The primers for detecting the gro-α gene were 5′-AAGAATGGGCGGAAAGC-3′ (forward) and 5′-CTCCTAAGCGATGCTCAAAC-3′ (reverse). The primers for the β-actin gene (ACTB) were 5′-TCCTTCCTGGGCATGGAGT-3′ (forward) and 5′-CAGGAGGAGCAATGATCTTGAT-3′ (reverse). PCR was performed as follows: 35 cycles consisting of denaturing at 95°C for 30 s, annealing at 55°C for 30 s, and extension at 72°C for 30 s with an initial denaturation of 5 min at 95°C and final extension of 5 min at 72°C. The PCR products were separated on a 1% agarose gel and analyzed using a UV imaging system.
For real-time quantitative RT-PCR (qRT-PCR), gro-α mRNA levels were determined with SYBR Green detection in a two-step reaction using the Eppendorf Mastercycler ep Realplex RT-PCR system (Eppendorf, Hamburg, Germany) as described previously . Relative expression levels were calculated using the 2-ΔΔCT method and were normalized to untreated control.
Enzyme-linked immunosorbent assay
To investigate the gro-α levels secreted by cells, cell supernatants were collected after treatment and examined using a gro-α ELISA kit according to the manufacturer’s instructions. Briefly, samples and standards were added to ELISA microplates and incubated for 1.5 h at room temperature. After washing, samples were incubated with gro-α conjugate for 1 h at 4°C, and then with substrate solution for 15 min at room temperature. The reaction was stopped using stop solution. The optical density (OD) of final products was measured using a microplate reader (Thermo Fisher Scientific, Shanghai, China) at 450 nm wavelength.
Cell proliferation analysis
Cells were seeded into 96-well plates at a density of 1 × 104 cells per well and incubated overnight. Cells were incubated with serum-free medium containing 1.5 μg of gro-α siRNA-NP or FSH33-gro-α siRNA-NP for 4 h. Medium was then replaced with fresh medium containing 10% fetal bovine serum. At 24 h, 48 h, 72 h and 96 h, 10 μl of CCK-8 solution was added and the cells incubated for 1 h. The OD values were measured using a microplate reader at 450 nm wavelength. The inhibition rate was calculated relative to untreated cells.
Cell migration assay
To study the effects of gro-α siRNA-loaded NPs on cell migration, a cell scratch assay was used. Cells in 24-well plates were treated as described above. After 72 h, the confluent cell monolayer was scraped with a 10 μl pipette tip. The cells were washed twice with medium and then cultured with serum-free medium. The cells were examined and photographed under light microscopy at 12 h and 36 h after scraping. The distances between one side of a scratch and the other were measured to evaluate cell migration ability.
Cell invasion assay
A transwell migration assay was used to determine the effects of gro-α siRNA-loaded NPs on cell invasion. Cells in 24-well plates were treated as described above. After 24 h, cells were harvested and seeded into the upper chambers of transwell plates pre-coated with matrigel at a density of 1 × 104 cells per well. After incubation for 24 h, cells were fixed by submerging the chambers in 4% paraformaldehyde for 30 min, and then stained with hematoxylin for 15 min. A cell count of migrated cells was determined by examining the chambers under light microscopy.
Statistical analyses were performed using Student’s t test by SPSS software. The data were expressed as the mean ± SD, and a P < 0.05 was considered significant.
Expression of FSHR and gro-α
Screening of siRNA sequences targeted to gro-α
Characterization of FSH β 33–53 peptide-conjugated gro-α siRNA-loaded NPs
Down-regulation of gro-α expression by FSH β 33–53 peptide-conjugated gro-α siRNA-loaded NPs
Suppression of aggressive biological behaviors of ES-2 cells by FSH β 33–53 peptide-conjugated gro-α siRNA-loaded NPs
To find an effective targeted therapy strategy for ovarian cancer and a stable delivery system for siRNA, we developed an active targeted gene delivery system mediated by FSHR and showed its promising effects for down-regulating the target gene and suppressing ovarian cancer cells.
Our group previously reported that an active targeted nanoparticle drug delivery system mediated by FSHR has a high selectivity for FSHR-positive ovarian cancer cells, and that the nanoparticles modified with FSH β 33–53 or β 81–95 peptide deliver more chemotherapeutic drugs into ovarian cancer cells and significantly enhance the antitumor efficacy of chemotherapeutic drugs [8, 9, 23]. Thus, FSH β 33–53 peptide was used as a targeting moiety in this gene delivery system.
However, the chemotherapeutic drugs we used before, such as paclitaxel, target ovarian cancer cells themselves rather than the whole tumor tissue. Tumors are well-organized tissues rather than a cluster of cancer cells. Tumor-associated stroma plays an important role as a niche for cancer cells and is not a passive bystander during the process of oncogenesis [24–26]. The stroma surrounding cancer epithelial cells not only provides a supportive and nutritive microenvironment for cancer cells, but it also assists in the development and progression of cancer [27–29]. The radiation-induced mammary stroma has been shown the potential to promote the neoplastic progression of non-tumorigenic mammary epithelial cells . Thus, the therapeutic approaches that only aim at cancer epithelial cells could not destroy the well-organized tumor tissue thoroughly. The remaining cancer cells or premalignant epithelium could proliferate again with the support of their surrounding stromal cells including inflammatory cells, endothelial cells and fibroblasts.
In order to create a favorable microenvironment, cancer cells might have a cross-talk with their surrounding stroma. Blocking the cross-talk network could suppress the development and progression of cancer. Recent studies have reported that pro-inflammatory cytokines such as gro-α, interleukin 6 (IL-6) and interleukin 8 (IL-8) have the potential to modulate stroma and promote tumor growth [20, 31, 32]. A model was hypothesized by Liu to describe the inflammatory network bridging senescent stroma and tumorigenesis . In this model, both initiated epithelium and senescent stroma can produce some molecules such as gro-α, IL-6 and IL-8, and then, they can promote further tumorigenesis and senescence by paracrine signaling. Gro-α and its receptor have been found to be overexpressed in ovarian cancers and play critical roles in the development and progression of ovarian cancer . Therefore, siRNA to silence gro-α was introduced into the FSHR-mediated delivery system and its antitumor effects were further evaluated in this study.
High levels of gro-α are essential for malignant transformation of normal ovarian epithelial cells and can promote the proliferation of tumor cells [20, 34]. It has been reported that the continuous expression of gro-α, -β, or -γ in immortalized melanocytes results in nearly 100% tumor formation in SCID mouse models. Antibodies to gro proteins are able to slow or inhibit the formation of tumors and suppress the angiogenic response . Silencing of gro-α with RNAi technology also results in a 20% decrease in esophageal cancer cell proliferation . In our study, the proliferation of the ovarian clear cell carcinoma cell line ES-2 was inhibited after gro-α was silenced with gro-α siRNA-loaded NPs. Compared with gro-α siRNA-loaded NPs without FSH peptide modification, gro-α siRNA-loaded NPs modified with FSH β 33–53 peptide showed an enhanced inhibitive effect to ES-2 cells. It could be due to the peptide fragments specifically binding to FSHR on ovarian cancer cells, thus greatly improving cell uptake by receptor-mediated endocytosis and internalization.
Gro-α over-expression is also involved in tumor cell migration and invasion, and ultimately promotes cancer metastasis [16, 19, 37]. Gro-α might be an independent predictor for bladder cancer metastasis . U251 glioma cells transfected with gro-α express high levels of several proteins associated with migratory behavior and exhibit stronger motility and invasiveness. The implantation of gro-α glioma clones into the brains of nude mice form larger intracerebral tumors and cause the early death of mice . In addition, CXC chemokines (including gro-α) that are secreted by endothelial cells can induce tumor cell invasion, whereas the blockade of the gro-α receptor CXCR2 can inhibit the invasion of oral squamous cell carcinoma-3 and Kaposi’s sarcoma cells into endothelial cells . Similarly, the invasion and migration of breast cancer cells is markedly reduced after treatment with anti-gro antibody . In colorectal cancer liver metastases, down-regulation of gro-α results in the inhibition of cell viability, invasion and proliferation in vitro and almost completely prevented tumor growth in vivo . We examined the migration and invasion activities of ES-2 cells by cell scratch and transwell migration assays. The data showed that silencing gro-α expression markedly inhibited cell migration and invasion. Compared to gro-α siRNA-loaded NPs, the complex modified with a targeting moiety had an enhanced suppressive effect on ES-2 cells, which indicated that targeting moieties such as receptor-binding peptides could improve the intake of siRNAs carried by NPs and could enhance the effect of RNA interference.
Taken together, this study indicated that silencing gro-α expression suppressed the proliferation, migration and invasion of ovarian clear cell carcinoma cells and that the FSHR-mediated nanoparticle delivery system provided a highly efficient delivery tool for gro-α siRNA into FSHR-expressing cells. Thus, silencing gro-α by a receptor-mediated targeted strategy is a potential choice for ovarian cancer treatment. However, further studies in vivo are required to investigate the therapeutic effects of this targeted complex in ovarian cancer.
Short interfering RNA
RNA interference technology
Follicle-stimulating hormone receptor
Growth regulated oncogene α
Cell counting kit-8
Enzyme-linked immunosorbent assay
Reverse transcription-polymerase chain reaction
Real-time quantitative RT-PCR
Gro-α siRNA-loaded NPs
FSH β 33–53 peptide-conjugated gro-α siRNA-loaded NPs
This work was supported by National Natural Sciences Foundation of China (30901588) awarded to XYZ and CJX, the Rising-Star Program of Shanghai Science and Technology Commission (10QA1401000) awarded to XYZ and CJX, the Youth Talent Foundation of Shanghai Health System (XYQ2011054) awarded to XYZ and CJX, and the Shanghai Talent Developing Foundation (2012047) awarded to XYZ.
- Twombly R: Cancer killer may be “silent” no more. J Natl Cancer Inst 2007, 99: 1359–1361. 10.1093/jnci/djm163PubMedView ArticleGoogle Scholar
- Tan DS, Kaye S: Ovarian clear cell adenocarcinoma: a continuing enigma. J Clin Pathol 2007, 60: 355–360.PubMed CentralPubMedView ArticleGoogle Scholar
- Kanasty R, Dorkin JR, Vegas A, Anderson D: Delivery materials for siRNA therapeutics. Nat Mater 2013, 12: 967–977. 10.1038/nmat3765PubMedView ArticleGoogle Scholar
- Shukla S, Sumaria CS, Pradeepkumar PI: Exploring chemical modifications for siRNA therapeutics: a structural and functional outlook. ChemMedChem 2010, 5: 328–349. 10.1002/cmdc.200900444PubMedView ArticleGoogle Scholar
- Patil ML, Zhang M, Betigeri S, Taratula O, He H, Minko T: Surface-modified and internally cationic polyamidoamine dendrimers for efficient siRNA delivery. Bioconjug Chem 2008, 19: 1396–1403. 10.1021/bc8000722PubMedView ArticleGoogle Scholar
- Yu B, Zhao X, Lee LJ, Lee RJ: Targeted delivery systems for oligonucleotide therapeutics. AAPS J 2009, 11: 195–203. 10.1208/s12248-009-9096-1PubMed CentralPubMedView ArticleGoogle Scholar
- Chen Y, Huang L: Tumor-targeted delivery of siRNA by non-viral vector: safe and effective cancer therapy. Expert Opin Drug Deliv 2008, 5: 1301–1311. 10.1517/17425240802568505PubMedView ArticleGoogle Scholar
- Zhang X, Chen J, Kang Y, Hong S, Zheng Y, Sun H, Xu C: Targeted paclitaxel nanoparticles modified with follicle-stimulating hormone beta 81–95 peptide show effective antitumor activity against ovarian carcinoma. Int J Pharm 2013, 453: 498–505. 10.1016/j.ijpharm.2013.06.038PubMedView ArticleGoogle Scholar
- Zhang XY, Chen J, Zheng YF, Gao XL, Kang Y, Liu JC, Cheng MJ, Sun H, Xu CJ: Follicle-stimulating hormone peptide can facilitate paclitaxel nanoparticles to target ovarian carcinoma in vivo . Cancer Res 2009, 69: 6506–6514. 10.1158/0008-5472.CAN-08-4721PubMedView ArticleGoogle Scholar
- Dong C, Chen J, Zhang X, Xu C: Follicle stimulating hormone receptor mediated gene delivery to target ovarian carcinoma in vitro. Asian Biomed 2012, 6: 185–194.Google Scholar
- Iida N, Grotendorst GR: Cloning and sequencing of a new gro transcript from activated human monocytes: expression in leukocytes and wound tissue. Mol Cell Biol 1990, 10: 5596–5599.PubMed CentralPubMedGoogle Scholar
- Egesten A, Eliasson M, Olin AI, Erjefalt JS, Bjartell A, Sangfelt P, Carlson M: The proinflammatory CXC-chemokines GRO-alpha/CXCL1 and MIG/CXCL9 are concomitantly expressed in ulcerative colitis and decrease during treatment with topical corticosteroids. Int J Colorectal Dis 2007, 22: 1421–1427. 10.1007/s00384-007-0370-3PubMedView ArticleGoogle Scholar
- Rubie C, Frick VO, Wagner M, Schuld J, Graber S, Brittner B, Bohle RM, Schilling MK: ELR+CXC chemokine expression in benign and malignant colorectal conditions. Bmc Cancer 2008, 8: 178. 10.1186/1471-2407-8-178PubMed CentralPubMedView ArticleGoogle Scholar
- Vazquez-Martin A, Colomer R, Menendez JA: Her-2/neu-induced “cytokine signature” in breast cancer. Adv Exp Med Biol 2008, 617: 311–319. 10.1007/978-0-387-69080-3_29PubMedView ArticleGoogle Scholar
- Wen Y, Giardina SF, Hamming D, Greenman J, Zachariah E, Bacolod MD, Liu H, Shia J, Amenta PS, Barany F, et al.: GROalpha is highly expressed in adenocarcinoma of the colon and down-regulates fibulin-1. Clin Cancer Res 2006, 12: 5951–5959. 10.1158/1078-0432.CCR-06-0736PubMedView ArticleGoogle Scholar
- Dannenmann C, Shabani N, Friese K, Jeschke U, Mylonas I, Bruning A: The metastasis-associated gene MTA1 is upregulated in advanced ovarian cancer, represses ERbeta, and enhances expression of oncogenic cytokine GRO. Cancer Biol Ther 2008, 7: 1460–1467. 10.4161/cbt.7.9.6427PubMedView ArticleGoogle Scholar
- Lee Z, Swaby RF, Liang Y, Yu S, Liu S, Lu KH, Bast RC Jr, Mills GB, Fang X: Lysophosphatidic acid is a major regulator of growth-regulated oncogene alpha in ovarian cancer. Cancer Res 2006, 66: 2740–2748. 10.1158/0008-5472.CAN-05-2947PubMedView ArticleGoogle Scholar
- Divella R, Daniele A, Savino E, Palma F, Bellizzi A, Giotta F, Simone G, Lioce M, Quaranta M, Paradiso A, Mazzocca A: Circulating levels of transforming growth factor-betaeta (TGF-beta) and chemokine (C-X-C motif) ligand-1 (CXCL1) as predictors of distant seeding of circulating tumor cells in patients with metastatic breast cancer. Anticancer Res 2013, 33: 1491–1497.PubMedGoogle Scholar
- Loukinova E, Dong G, Enamorado-Ayalya I, Thomas GR, Chen Z, Schreiber H, Van Waes C: Growth regulated oncogene-alpha expression by murine squamous cell carcinoma promotes tumor growth, metastasis, leukocyte infiltration and angiogenesis by a host CXC receptor-2 dependent mechanism. Oncogene 2000, 19: 3477–3486. 10.1038/sj.onc.1203687PubMedView ArticleGoogle Scholar
- Yang G, Rosen DG, Zhang Z, Bast RC Jr, Mills GB, Colacino JA, Mercado-Uribe I, Liu J: The chemokine growth-regulated oncogene 1 (Gro-1) links RAS signaling to the senescence of stromal fibroblasts and ovarian tumorigenesis. Proc Natl Acad Sci USA 2006, 103: 16472–16477. 10.1073/pnas.0605752103PubMed CentralPubMedView ArticleGoogle Scholar
- Yang G, Rosen DG, Liu G, Yang F, Guo X, Xiao X, Xue F, Mercado-Uribe I, Huang J, Lin SH, et al.: CXCR2 promotes ovarian cancer growth through dysregulated cell cycle, diminished apoptosis, and enhanced angiogenesis. Clin Cancer Res 2010, 16: 3875–3886. 10.1158/1078-0432.CCR-10-0483PubMed CentralPubMedView ArticleGoogle Scholar
- Furuya M, Suyama T, Usui H, Kasuya Y, Nishiyama M, Tanaka N, Ishiwata I, Nagai Y, Shozu M, Kimura S: Up-regulation of CXC chemokines and their receptors: implications for proinflammatory microenvironments of ovarian carcinomas and endometriosis. Hum Pathol 2007, 38: 1676–1687. 10.1016/j.humpath.2007.03.023PubMedView ArticleGoogle Scholar
- Zhang XY, Chen J, Gao XL, Sun H, Xu CJ: [Preparation and in vitro targeting of follicle stimulating hormone polypeptide modified nanoparticles]. Zhonghua Fu Chan Ke Za Zhi 2008, 43: 533–537.PubMedGoogle Scholar
- Qiu W, Hu M, Sridhar A, Opeskin K, Fox S, Shipitsin M, Trivett M, Thompson ER, Ramakrishna M, Gorringe KL, et al.: No evidence of clonal somatic genetic alterations in cancer-associated fibroblasts from human breast and ovarian carcinomas. Nat Genet 2008, 40: 650–655. 10.1038/ng.117PubMed CentralPubMedView ArticleGoogle Scholar
- Mueller MM, Fusenig NE: Friends or foes - bipolar effects of the tumour stroma in cancer. Nat Rev Cancer 2004, 4: 839–849.PubMedView ArticleGoogle Scholar
- Tlsty TD, Hein PW: Know thy neighbor: stromal cells can contribute oncogenic signals. Curr Opin Genet Dev 2001, 11: 54–59. 10.1016/S0959-437X(00)00156-8PubMedView ArticleGoogle Scholar
- Dutsch-Wicherek M: RCAS1, MT, and vimentin as potential markers of tumor microenvironment remodeling. Am J Reprod Immunol 2010, 63: 181–188. 10.1111/j.1600-0897.2009.00803.xPubMedView ArticleGoogle Scholar
- Yao Q, Qu X, Yang Q, Good DA, Dai S, Kong B, Wei MQ: Blockage of transdifferentiation from fibroblast to myofibroblast in experimental ovarian cancer models. Mol Cancer 2009, 8: 78. 10.1186/1476-4598-8-78PubMed CentralPubMedView ArticleGoogle Scholar
- Maffini MV, Soto AM, Calabro JM, Ucci AA, Sonnenschein C: The stroma as a crucial target in rat mammary gland carcinogenesis. J Cell Sci 2004, 117: 1495–1502. 10.1242/jcs.01000PubMedView ArticleGoogle Scholar
- Barcellos-Hoff MH, Ravani SA: Irradiated mammary gland stroma promotes the expression of tumorigenic potential by unirradiated epithelial cells. Cancer Res 2000, 60: 1254–1260.PubMedGoogle Scholar
- Kuilman T, Michaloglou C, Vredeveld LC, Douma S, van Doorn R, Desmet CJ, Aarden LA, Mooi WJ, Peeper DS: Oncogene-induced senescence relayed by an interleukin-dependent inflammatory network. Cell 2008, 133: 1019–1031. 10.1016/j.cell.2008.03.039PubMedView ArticleGoogle Scholar
- Sparmann A, Bar-Sagi D: Ras-induced interleukin-8 expression plays a critical role in tumor growth and angiogenesis. Cancer Cell 2004, 6: 447–458. 10.1016/j.ccr.2004.09.028PubMedView ArticleGoogle Scholar
- Shan W, Yang G, Liu J: The inflammatory network: bridging senescent stroma and epithelial tumorigenesis. Front Biosci (Landmark Ed) 2009, 14: 4044–4057.View ArticleGoogle Scholar
- Suzuki H, Mori M, Seto K, Shibata F, Nagahashi S, Kawaguchi C, Suzuki M, Matsui H, Watanabe K, Miura S, Ishii H: Rat CXC chemokine GRO/CINC-1 paradoxically stimulates the growth of gastric epithelial cells. Aliment Pharmacol Ther 2000,14(Suppl 1):94–100.PubMedView ArticleGoogle Scholar
- Luan J, Shattuck-Brandt R, Haghnegahdar H, Owen JD, Strieter R, Burdick M, Nirodi C, Beauchamp D, Johnson KN, Richmond A: Mechanism and biological significance of constitutive expression of MGSA/GRO chemokines in malignant melanoma tumor progression. J Leukoc Biol 1997, 62: 588–597.PubMedGoogle Scholar
- Wang B, Hendricks DT, Wamunyokoli F, Parker MI: A growth-related oncogene/CXC chemokine receptor 2 autocrine loop contributes to cellular proliferation in esophageal cancer. Cancer Res 2006, 66: 3071–3077. 10.1158/0008-5472.CAN-05-2871PubMedView ArticleGoogle Scholar
- Li A, Varney ML, Singh RK: Constitutive expression of growth regulated oncogene (gro) in human colon carcinoma cells with different metastatic potential and its role in regulating their metastatic phenotype. Clin Exp Metastasis 2004, 21: 571–579.PubMedView ArticleGoogle Scholar
- Kawanishi H, Matsui Y, Ito M, Watanabe J, Takahashi T, Nishizawa K, Nishiyama H, Kamoto T, Mikami Y, Tanaka Y, et al.: Secreted CXCL1 is a potential mediator and marker of the tumor invasion of bladder cancer. Clin Cancer Res 2008, 14: 2579–2587. 10.1158/1078-0432.CCR-07-1922PubMedView ArticleGoogle Scholar
- Zhou Y, Zhang J, Liu Q, Bell R, Muruve DA, Forsyth P, Arcellana-Panlilio M, Robbins S, Yong VW: The chemokine GRO-alpha (CXCL1) confers increased tumorigenicity to glioma cells. Carcinogenesis 2005, 26: 2058–2068. 10.1093/carcin/bgi182PubMedView ArticleGoogle Scholar
- Warner KA, Miyazawa M, Cordeiro MM, Love WJ, Pinsky MS, Neiva KG, Spalding AC, Nor JE: Endothelial cells enhance tumor cell invasion through a crosstalk mediated by CXC chemokine signaling. Neoplasia 2008, 10: 131–139. 10.1593/neo.07815PubMed CentralPubMedView ArticleGoogle Scholar
- Li J, Sidell N: Growth-related oncogene produced in human breast cancer cells and regulated by Syk protein-tyrosine kinase. Int J Cancer 2005, 117: 14–20. 10.1002/ijc.21074PubMedView ArticleGoogle Scholar
- Bandapalli OR, Ehrmann F, Ehemann V, Gaida M, Macher-Goeppinger S, Wente M, Schirmacher P, Brand K: Down-regulation of CXCL1 inhibits tumor growth in colorectal liver metastasis. Cytokine 2012, 57: 46–53. 10.1016/j.cyto.2011.10.019PubMedView ArticleGoogle Scholar
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.