小蘖鹼為一種異喹啉生物鹼，存在於小蘖科植物的根、莖或樹皮中，具有抗心律不整及抗腫瘤的功效。為了找出小蘖鹼在 HER2/neu 過表現細胞中的化學預防分子作用機制，我們分析數個不同 p185HER2/neu 蛋白質表現量的細胞株，結果發現相較於正常 HER2/neu 表現量的細胞株，小蘖鹼會針對 HER2/neu 過表現的細胞株有較高抑制細胞存活率的效果。此外小蘖鹼在 HER2/neu 過表現的細胞株會有依劑量及依時間抑制 p185HER2/neu 蛋白質表現量的情形。進一步觀察發現小蘖鹼會抑制 p185HER2/neu 的活性及其下游 Akt 與 ERK 的活性。此外我們發現小蘖鹼會抑制 p185HER2/neu 過表現的卵巢癌細胞 (SKOV3) 的轉移能力。另外也證明了 EGF 會回覆藉由小蘖鹼所抑制的 MMP2 的活性，而 PI3K 的抑制劑會抑制由 EGF 所回覆的 MMP2 活性。綜合所有的實驗結果可說明，小蘖鹼會促進 p185HER2/neu 蛋白質降解而造成 HER2/neu 過表現細胞的損壞，並藉由抑制PI3K/Akt 訊號路徑進而減弱了由 p185HER2/neu 所調控的轉移情形。

Berberine, an isoquinoline alkaloid, present in the roots, rhizome and stem bark of Berberis species, has been shown to possess potent anti-arrhythmic and anti-turmor properties. To explore the molecular mechanism of the chemopreventive effects of berberine in the HER2/neu-overexpressing cancer cells, we examined several human cancer cell lines having different levels p185HER2/neu expression and found that berberine exhibited much more growth-inhibitory activity in the HER2/neu-overexpressing cancer cells than those cells expressing basal levels of p185HER2/neu. Depletion of p185HER2/neu was also observed in HER2/neu-overexpressing cancer cells in a dose- and time-dependant manner. We also demonstrate that berberine can downregulate the activated form of p185HER2/neu as well as Akt and ERK, downstream substrates of p185HER2/neu. Furthermore, we found that berberine is potent in suppressing transformation phenotype of SKOV3 cells (HER2/neu-overexpressing ovarian cancer cell) including metastasis-associated properties. We also elucidate that EGF specifically restores the activation of MMP2 after its activity was reduced by berberine; the restoration of MMP2 activity was also inhibited by PI3K inhibitor. These finding suggest that berberine can cause HER2/neu-overexoressing cancer cell damage by inducing degradation of p185HER2/neu, and then inhibiting the PI3K/Akt-signaling pathway to attenuate the p185HER2/neu mediated metastasis.

目錄
謝誌---------------------------------------------------------------------------------I
中文摘要-------------------------------------------------------------------------III
英文摘要--------------------------------------------------------------------------V
目錄------------------------------------------------------------------------------VII
圖目錄-----------------------------------------------------------------------------X
表目錄----------------------------------------------------------------------------XI
附錄目錄------------------------------------------------------------------------XII
縮寫表--------------------------------------------------------------------------XIII
第一章、前言-----------------------------------------------------------------------1
   第一節、實驗緣起與目的---------------------------------------------------1
第二章、序論-----------------------------------------------------------------------2
   第ㄧ節、小蘖鹼---------------------------------------------------------------2
       壹、小蘖鹼簡介 --------------------------------------------------------2
       貳、小蘖鹼的生理功能------------------------------------------------2
   第二節、癌細胞的生長------------------------------------------------------3
       壹、簡介------------------------------------------------------------------3
       貳、細胞增生------------------------------------------------------------3
       参、癌細胞的轉移------------------------------------------------------4
       肆、血管新生------------------------------------------------------------4
   第三節、神經膠原致癌基因 (HER2/neu)--------------------------------5
       壹、簡介------------------------------------------------------------------5
   第四節、p185HER2/neu 與癌細胞生長、轉移及血管新生之關係-------7
       壹、p185HER2/neu 與癌細胞生長之關係-----------------------------7
       貳、p185HER2/neu 與癌細胞轉移之關係-----------------------------8
       参、p185HER2/neu 與癌細胞血管新生之關係----------------------11
   第五節、研究目標-----------------------------------------------------------12
第三章、材料與方法------------------------------------------------------------13
   第一節、實驗材料-----------------------------------------------------------13
       壹、細胞株 (Cell lines)-----------------------------------------------13
       貳、抗體 (Antibodies)------------------------------------------------14
       参、化學藥品與試劑 (Chemicals and reagents)------------------14
       肆、主要儀器與器材--------------------------------------------------16
   第二節、實驗方法-----------------------------------------------------------17
       壹、小蘖鹼配置方法--------------------------------------------------17
       貳、錐藍排除分析 (Trypan blue dye exclusion assay)----------17
       参、西方墨點法 (Western blotting)--------------------------------18
       肆、細胞傷痕試驗 (Scratch-wound assay)------------------------19
       伍、細胞穿膜實驗 (Transwell assay)------------------------------20
       陸、酶譜法 (Zymography)-------------------------------------------20
第四章、實驗結果---------------------------------------------------------------22
       壹、小蘖鹼有效抑制 p185HER2/neu 過表現細胞株的存活率--22
       貳、小蘖鹼抑制 p185HER2/neu 蛋白質是經由蛋白質的降解路徑--------------------------------------------------------------------23
       参、小蘖鹼對 p185HER2/neu 下游 PI3K/Akt 與 ERK 路徑的影響--------------------------------------------------------------------24
       肆、小蘖鹼抑制 SKOV3細胞的轉移能力-----------------------25
       伍、小蘖鹼藉由 HER2/PI3K/Akt 路徑抑制 MMP2 酵素的活性--------------------------------------------------------------------26
第五章、討論---------------------------------------------------------------------28
第六章、結論---------------------------------------------------------------------34
第七章、參考文獻---------------------------------------------------------------35
圖-----------------------------------------------------------------------------------46
表-----------------------------------------------------------------------------------53
附錄--------------------------------------------------------------------------------58



圖目錄
圖 1. 小蘖鹼 (Berberine) 的結構圖及分子量---------------------------46
圖 2. 小蘖鹼有效抑制 p185HER2/neu 過表現細胞株的存活率---------47
圖 3. 小蘖鹼抑制 p185HER2/neu 蛋白質是經由蛋白質的降解路徑---48
圖 4. 小蘖鹼對 p185HER2/neu 下游 PI3K/Akt 與 ERK 路徑的影響49
圖 5. 小蘖鹼抑制 SKOV3細胞的轉移能力------------------------------50
圖 6. 小蘖鹼藉由 HER2/PI3K/Akt 路徑抑制 MMP2 酵素的活性-51
圖 7. 小蘖鹼抑制 SKOV3 細胞的增生與轉移之路徑-----------------52















表目錄
表1. 細胞株基本資料---------------------------------------------------------53
表2. 西方墨點法之抗體資料------------------------------------------------54
表 3. 化學藥品及試劑 (Chemicals and reagents)------------------------55




















附錄目錄
附錄 1. 細胞培養使用之緩衝液--------------------------------------------58
附錄 2. 西方墨點法 (Western blotting) 使用之緩衝液----------------59

Abidi P, Zhou Y, Jiang JD and Liu J, 2005. Extracellular Signal-Regulated Kinase–Dependent Stabilization of Hepatic Low-Density Lipoprotein Receptor mRNA by Herbal Medicine Berberine. Arterioscler. Thromb. Vasc. Biol. 25, 2170-2176
Allgayer H, Babic R, Gruetzner KU, Tarabichi A , Schildberg FW and Heiss MM, 2000. c-erbB-2 Is of Independent Prognostic Relevance in Gastric Cancer and Is Associated With the Expression of Tumor-Associated Protease Systems. Journal of Clinical Oncology 18(11), 2201-2209 
Anis KV, Rajeshkumar NV and Kuttan R, 2001. Inhibition of chemical carcinogenesis by berberine in rats and mice. J Pharmacy Pharmacol 53(5), 763-768
Bando H, 2007. Vascular Endothelial Growth Factor and Bevacitumab inBreast Cancer. Breast Cancer 14(2), 163-173, Review
Ben-Av P, Crofford LJ, Wilder RL and Hla T, 1995. Induction of vascular endothelial growth factor expression in synovial fibroblasts by prostaglandin E and interleukin-1: a potential mechanism for inflammatory angiogenesis. FEBS Lett. 372, 83-87
Bergman MR, Cheng S, Honbo N, Piacentini L, Karliner JS, and Lovett DH, 2003. A functional activating protein 1 (AP-1) site regulates matrix metalloproteinase 2 (MMP-2) transcription by cardiac cells through interactions with JunB-Fra1 and JunB-FosB heterodimers. Biochem j. 369(Pt 3), 485-496
Berney CR, Yang J, Fisher RJ, Russell PJ and Crowe PJ, 1998. Correlates of urokinase-type plasminogen activator in colorectal cancer: positive relationship with nm23 and c-erbB-2 protein expression. Oncol Res. 10(1), 47-54
Bogenrieder T and Herlyn M, 2003. Axis of evil: molecular mechanisms of cancer metastasis. Oncogene 22, 6524-6536
Bosc DG, Goueli BS and Janknecht R, 2001, HER2/Neu-mediated activation of the ETS transcription factor ER81 and its target gene MMP-1. Oncogene 20(43), 6215-6224
Cai W, Niu G and Chen, 2008. Multimodality imaging of the HER-kinase axis in cancer. Eur J Nucl Med Mol Imaging. 35(1), 186-208
Casimiro M, Rodriguez O, Pootrakul L, Aventian M, Lushina N, Cromelin C, Ferzli G, Johnson K, Fricke S, Diba F, Kallakury B, Ohanyerenwa C, Chen M, Ostrowski M, Hung M-C, Rabbani S A, Datar R, Cote R, Pestell R and Albanese C, 2007. ErbB-2 induces the cyclin D1 gene in prostate epithelial cells in vitro and in vivo. Cancer Res. 67(9), 4364-72
Chiang CT, Way TD, Tsai SJ and Lin JK, 2007. Diosgenin, a naturally occurring steroid, suppresses fatty acidsynthase expression in HER2-overexpressing breast cancer cells through modulating Akt, mTOR and JNK phosphorylation. FEBS Letters 581, 5735-5742
Chuang TC, Lee YJ, Liu JY, Lin YS, Li JW, Wang VC, Law SL,h and Kao MC, 2003. EBNA1 may prolong G2/M phase and sensitize HER2/neu-overexpressing ovarian cancer cells to both topoisomerase II-targeting and paclitaxel drugs. Biochemical and Biophysical Research Communications 307, 653-659
Chuang TC, Liu JY, Lin CT, Tang YT, Yeh MH, Chang SC, Lig JW and Kao MC, 2007. Human manganese superoxide dismutase suppresses HER2/neu-mediated breast cancer malignancy. FEBS Letters 581, 4443-4449
Chuang TC, Yu YH, Lin YS, Wang SS and Kao MC, 2002. The N-terminal domain of SV40 large T antigen represses the HER2/neumediated transformation and metastatic potential in breast cancers. FEBS Letters 511, 46-50
Curran T, Franza, BR Jr., 1988. Fos and Jun: the AP-1 connection. Cell 55, 395-397
Dohadwala M, Luo J, Zhu L, Lin Y, Dougherty GJ, Sharma S, Huang M, Pold M, Batra RK and Dubinett SM, 2001. Non-small cell lung cancer cyclooxygenase-2-dependent invasion is mediated by CD44. J. Biol. Chem. 276, 20809-20812
Duffy MJ, Maguire TM, Hill A, McDermott E and O’Higgins N, 2000. Metalloproteinases: role in breast carcinogenesis, invasion and metastasis. Breast Cancer Res. 2(4), 252-257
Fleming IN, Hogben M, Frame S, McClue SJ and Green SR, 2008. Synergistic inhibition of ErbB signaling by combined treatment with seliciclib and ErbB-targeting agents. Clin. Cancer Res. 14(13), 4326-4335
Fukuda K, Hibiya Y, Mutoh M, Koshiji M, Akao S and Fujiwara H, 1999. Inhibition of activator protein 1 activity by berberine in human hepatoma cells. Planta Med. 65, 381-383
Giunciuglio D, Culty M, Fassina G, Masiello L, Melchiori A, Paglialunga G, Arand G, Ciardiello F, Basolo F, Thompson EW and Albini A, 1995. Invasive phenotype of MCF10A cells overexpressing c-Ha-ras and c-erbB-2 oncogenes. Int. J. Cancer 63, 1171-1185 
Goueli B S. and Janknecht R, 2004. Upregulation of the Catalytic Telomerase Subunit by the Transcription Factor ER81 and Oncogenic HER2/Neu, Ras, or Raf. Molecular and Cellular Biology 24(1), 25-35
Hanemaaijer R, Verheijen JH, Maguire TM, Visser H, Toet K, McDermott E, O’Higgins N and Duffy MJ, 2000.Increased gelatinase-A and gelatinase-B activities in malignant vs. benign breast tumors. Int. J. Cancer 86(2), 204-207
Hayashi H, Kimura M, Yoshimoto N, Tsuzuki M, Tsunoda N, Yamashita T and Iwata H, 2008. A case of HER2-positive male breast cancer with lung metastases showing a good response to trastuzumab and paclitaxel treatment. Breast Cancer
Hong RL, Spohn WH. and Hung MC, 1999. Curcumin Inhibits Tyrosine Kinase Activity of p185neu and Also Depletes p185neu. Clic Cancer Res. 5(7), 1884-1891
Hsu MC, Chang HC, Hung WC, 2006. HER-2/neu Represses the Metastasis Suppressor RECK via ERK and Sp Transcription Factors to Promote Cell Invasion. The Journal of Biological Chemistry 281(8), 4718-4725
Hwang JM, Kuo HC, Tseng TH, Liu JY and Chu CY, 2006. Berberine induces apoptosis through a mitochondria/caspases pathway in
human hepatoma cells. Arch Toxicol, 80, 62-73
Jia XS, Zhang DR and Sun AJ, 1994. The expression of c-Fos, c-Jun and phosphotyrosine gene products in lung cancer. Zhonghua Binglixue Zazhi 23, 264-266
Liabakk NB, Talbot I, Smith RA, Wilkinson K and Balkwill F, 1996. Matrix metalloprotease 2 (MMP-2) and matrix metalloprotease 9 (MMP-9) type IV collagenases in colorectal cancer. Cancer Res. 56, 190-196
Johnsen M, Lund LR, Romer J, Almholt K and Dano K, 1998. Cancer invasion and tissue remodeling: common themes in proteolytic matrix degradation, Curr. Opin. Cell Biol. 10, 667-671
Konecny G, Untch M, Arboleda J, Wilson C, Kahlert S, Boettcher B, Felber M, Beryt M, Lude S, Hepp H, Slamon D and Pegram M, 2001. HER-2/neu and Urokinase-Type Plasminogen Activator and Its Inhibitor in Breast Cancer. Clin. Cancer Res. 7, 2448-2457
Kuo CL, Chi CW, Liu TY, 2004. The anti-inflammatory potential of
berberine in vitro and in vivo. Cancer Lett, 203, 127-137
Kao MC, Liu GY, Chuang TC, Lin YS, Wuu JA and Law SL, 1998. The N-terminal 178-amino-acid domain only of the SV40 large T antigen acts as a transforming suppressor of the Her-2/neu oncogene. Oncogen 16, 547-554 
La Rocca G, PucciMI, MarrazzoA, Taormina P and Minafra, 2004. Zymographic detection and clinical correlations of MMP-2 and MMP9 in breast cancer sera. British Journal of Cancer 90, 1414-1421
Laughner E, Taghavi P, Chiles K, Mahon P C., and Semenza G L, 2001. HER2 (neu) Signaling Increases the Rate of Hypoxia-Inducible Factor 1α (HIF-1α) Synthesis: Novel Mechanism for HIF-1-Mediated Vascular Endothelial Growth Factor Expression. Molecular and Cellular Biology 21(12), 3995-4004
Lerdrup M, Bruun S, Grandal MV., Roepstorff K, Kristensen MM., Hommelgaard AM., and van DeursB, 2007. Endocytic Down-Regulation of ErbB2 Is Stimulated by Cleavage of Its C-Terminus. Mol Biol Cell. 18(9), 3656-3666
Li XK, Motwani M, Tong W, Bornmann W, and Schwartz GK, 2000. Huanglian, A Chinese Herbal Extract, Inhibits Cell Growth by Suppressing the Expression of Cyclin B1 and Inhibiting CDC2 Kinase Activity in Human Cancer Cells. Mol Pharmacol 58, 1287-1293
Li YM., Pan Y, Wei Y, Cheng X, Zhou B P., Tan M, Zhou X, Weiya X, Hortobagyi G N., Yu D, and Hung MC, 2004. Upregulation of CXCR4 is essential for HER2-mediated tumor metastasis. Cancer Cell 6, 459-469
Lin JP, Yang JS, Lee JH, Hsieh WT, Chung JG, 2006. Berberine induces cell cycle arrest and apoptosis in human gastric carcinoma SNU-5 cell line.  World J Gastroenterol 12(1), 21-28
Lin YC, Peng JM and Wang WB, 2000. The N-terminal common domain of simian virus 40 large T and small t aitigens as a transformation suppressor of the HER-2/neu oncogene. Oncogene 19, 2704-2713
Liotta LA, 2001. An attractive force in metastasis. Nature 410(6824), 24-25
Luo J., Role of matrix metalloproteinase-2 in ethanol-induced invasion by breast cancer cells. 2006, J Gastroenterol Hepatol 21, 65-68, Review
Mantena SK., Sharma SD. and Katiyar SK, 2006a. Berberine inhibits growth, induces G1 arrest and apoptosis in human epidermoid carcinoma A431 cells by regulating Cdki–Cdk-cyclin cascade, disruption of mitochondrial membrane potential and cleavage of caspase 3 and PARP. Carcinogenesis 27, 2018-2027
Mantena SK, Sharma SD, and Katiyar SK, 2006b. Berberine, a natural product, induces G1-phase cell cycle arrest and caspase-3-dependent apoptosis in human prostate carcinoma cells. Mol Cancer Ther 5(2), 296-308
Matin A and Hung MC, 1993. Negative regulation of neu promoter by the SV40 large T antigen. Cell Growth Differ 4, 1051-1056
Matin A and Hung MC, 1994. The retinoblastoma gene product, Rb, represses neu expression through two regions within the neu regulatory sequence. Oncogene 9, 1333-1339
McKeage K, Lyseng-Williamson KA, 2008. Trastuzumab: a pharmacoeconomic review of its use in early breast cancer. Pharmacoeconomics 26(8), 699-719
Mimnaugh EG, Chavany C and Neckers L, 1996. Polyubiquitination and Proteasomal Degradation of the p185c-erbB-2 Receptor Protein-tyrosine Kinase Induced by Geldanamycin. J. Biol. Chem. 271, 22796-22801
Mizuguchi G, Kanei-Ishii C, Takahashi T, Yasukawa T, Nagase T, Horikoshi M, Yamamoto T and Ishii S, 1995. c-Myb repression c-erbB-2 transcription by direct binding to the c-erbB-2 promotor. J. Biol. Chem. 270, 9384-9389
Muller A, Homey B, Soto H, Ge N, Catron D, Buchanan ME, McClanahan T, Murphy E, Yuan W, Wagner SN, Barrera JL, Mohar A, Verastegui E and Zlotinik A, 2001. Involvement of chemokine receptors in breast cancer metastasis. Nature 410(6824), 50-56
Ou cc, Hsu SC, Hsieh YH, Tsou WL, Chuang TC, Liu JY and Kao MC, 2008. Downregulation of HER2 by RIG1 involves the PI3K/Akt pathway in ovarian cancer cells. Carcinogenesis 29(2), 299-306
Pellikainen JM, Ropponen KM, Kataja VV, Kellokoski JK, Eskelinen MJ and Kosma VM, 2004. Expression of matrix metalloproteinase (MMP)-2 and MMP-9 in breast cancer with a special reference to activator protein-2, HER2, and prognosis. Clin Cancer Res. 10(22), 7621-7628
Peng PL, Hsieh YS, Wang CJ, Hsu JL, Chou FP, 2006. Inhibitory effect of berberine on the invasion of human lung cancer cells via decreased productions of urokinase-plasminogen activator and matrix metalloproteinase-2. Toxicology and Applied Pharmacolog, 214, 8-15
Philip S and Kundu GC, 2003. Osteopontin Induces Nuclear FactorκB-mediated Promatrix Metalloproteinase-2 Activation through IκBα/IKK Signaling Pathways, and Curcumin (Diferulolylmethane) Down-regulates These Pathways. J. Biol. Chem. 278(16), 14487-14497
Piyanuch R, Sukhthankar M, Wandee G, Baek S J, 2007. Berberine, a natural isoquinoline alkaloid, induces NAG-1 and ATF3 expression in human colorectal cancer cells. Cancer Letters 258, 230-240
Roskoski R, Jr., 2004. The ErbB/HER receptor protein-tyrosine kinases and cancer. Biochem Biophys Res Commun. 319(1), 1-11
Sato H, Takino T, Miyamori H, 2005. Roles of membrane-type matrix metalloproteinase-1 in tumor invasion and metastasis. Cancer Sci. 96, 212-217
Schiller LR., 1995. Review article: anti-diarrhoeal pharmacology and
therapeutics. Aliment Pharmacol Ther 9, 87-106
Sheng H, Shao J, Morrow JD, Beauchamp RD and DuBois RN, 1998. Modulation of apoptosis and Bcl-2 expression by prostaglandin E2 in human colon cancer cells. Cancer Res. 58, 362-366
Sheng H, Shao J, Washington MK and DuBois RN, 2001. Prostaglandin E2 increases growth and motility of colorectal carcinoma cells. J. Biol. Chem. 276, 18075-18081
Sounni NE, Janssen M and Foidart JM, 2003. Noel, Membrane type-1 matrix metalloproteinase and TIMP-2 in tumor angiogenesis. Matrix Biol. 22, 55-61
Subbaramaiah K, Norton L, Gerald W and Dannenberg AJ, 2002. Cyclooxygenase-2 is overexpressed in HER-2/neu-positive breast cancer: evidence for involvement of AP-1 and PEA3. J. Biol. Chem. 277, 18649-18657
Suen TC and Hung MC, 1991. c-myc reverses neu-induced transformed morphology by transcriptional repression. Mol. Cell. Biol. 11, 354-362
Tang FY, Chiang EP and Sun YC, 2008a.Resveratrol inhibits heregulin-β1-mediated matrix metalloproteinase-9 expression and cell invasion in human breast cancer cells. J Nutr Biochem 19(5), 287-294
Tang FY, Su YC, Chen NC, Hsieh HS and Chen KS, 2008b. Resveratrol inhibits migration and invasion of human breast-cancer cells. Mol. Nutr. Food Res. 52, 683-691
Tsujii M and DuBois RN, 1995. Alterations in cellular adhesion and apoptosis in epithelial cells overexpressing prostaglandin endoperoxide synthase 2. Cell 83, 493-501
Tsujii M, Kawano S and DuBois RN, 1997. Cyclooxygenase-2 expression in human colon cancer cells increases metastatic potential. Proc. Natl. Acad. Sci. U. S. A. 94, 3336-3340
Tsujii M, Kawano S, Tsuji S, Sawaoka H, Hori M and DuBois RN, 1998. Cyclooxygenase regulates angiogenesis induced by colon cancer cells. Cell 93, 705-716
Vadlamudi R, Mandal M, Adam L, Steinbach G, Mendelsohn J and Kumar R, 1999. Regulation of Cyclooxygenase-2 pathway by HER2 receptor. Oncogene 18, 305-314
Vihinen P and Kahari VM, 2002. Matrix metalloproteinases in cancer: prognostic markers and therapeutic targets. Int. J. Cancer 99, 157–166
Volm M, Drings P and Wodrich W, 1993. Probnostic significance of the expression of c-fos, c-jun and c-erbB-1 oncogen products in human squamouse cell lung carcinomas. J. Cancer Res. Clin. Oncol. 119, 507-510
Way TD, Kao MC and Lin JK, 2004. Apigenin Induces Apoptosis through Proteasomal Degradation of HER2/neu in HER2/neu-overexpressing Breast Cancer Cells via the Phosphatidylinositol 3-Kinase/Akt-dependent Pathway. J. Biol. Chem., 279(6), 4479-4489
Xu W., Mimnaugh E., Rosser M. F., Nicchitta C., Marcu M., Yarden Y., and Neckers L, 2001, Sensitivity of Mature ErbB2 to Geldanamycin Is Conferred by Its Kinase Domain and Is Mediated by the Chaperone Protein Hsp90. J. Biol. Chem. 276, 3702-3708
Yao J, Xiong S, Klos K, Nguyen N, Grijalva R, Li P and Yu D, 2001. Multiple signaling pathways involved in activation of matrix metalloproteinase-9 (MMP-9) by heregulin-β1 in human breast cancer cells. Oncogene 20(56), 8066-8074