Inhibiting LOX expression decreases tumor cell invasion & mets

[Rich66]

Researchers uncover 'relocation' plan of metastatic cancer cells
http://www.physorg.com/pdf150383375.pdf

Few things are as tiresome as house hunting and moving. Unfortunately, metastatic cancer cells have the relocation process down pat. Tripping nimbly from one abode to another, these migrating cancer cells often prove far more deadly than the original tumor. Although little has been known about how these rogue cells choose where to put down roots, researchers at the Stanford University School of Medicine have now learned just how nefarious they are.
"Metastasis is not a passive process," said cancer biologist Amato Giaccia, PhD. "Cells don't just break off the primary tumor and lodge someplace else. Instead the cells actually secrete substances to precondition target tissue and make it more amenable to subsequent invasion."
In other words, the cells plan ahead by first sending molecular emissaries to orchestrate a breach in the body's natural defenses. Blocking this cascade of events in mice hobbled the cells' migration and prevented the metastatic cancer that developed in control animals. The researchers are hopeful that a similar tactic will be equally successful in humans.
Giaccia, the Jack, Lulu and Sam Willson Professor and professor of radiation oncology at Stanford, is the senior author of the research, which will be published in the Jan. 6 issue of Cancer Cell. Giaccia is also a member of the Stanford Cancer Center.
Scientists have known for some time that certain primary cancers metastasize preferentially to other organs — breast cancer often spreads to the lungs, for example. This is in part due to the patterns of blood flow in the body. They also knew that such future colonization sites, called pre-metastatic niches, harbor large numbers of cells derived from the bone marrow that somehow facilitate the cancer cells' entry. What they didn't know is how the bone-marrow-derived cells were summoned, and what, if any, role the primary tumor cells played in site selection.
Giaccia and his colleagues turned their attention to a substance that they had previously shown to be involved in metastasis: a protein called lysyl oxidase, or LOX. In healthy people, LOX works to strengthen developing connective tissue by modifying collagen and elastin, which are components of the extracellular matrix surrounding many organs. LOX expression increases in cancer cells deprived of oxygen — a condition called hypoxia that begins to occur when blood vessels fail to reach the inner cells of a growing tumor mass. Inhibiting LOX expression decreases tumor cell invasion and metastasis in the lungs of mice implanted with human breast cancer cells.
The researchers wanted to know how LOX affected metastasis. In the current study, they found that blocking LOX expression in the mice not only prevented metastases, it also kept the bone-marrow-derived cells necessary for niche formation from flocking to the site. When LOX was present, it accumulated in the lungs of the mice and was associated with one particular type of bone-marrow-derived cell known as a CD11b cell. CD11b cells, in turn, secreted a protein that breaks apart collagen and provides a handy entry point for the soon-to-arrive cancer cells.
"We've never really understood before how normal tissues are modified to allow metastases to target and successfully invade them," said Giaccia, who is hoping to devise a clinical trial to study the effect of blocking LOX activity in humans with primary cancers. "Now we know that LOX goes to the target tissue and attracts CD11b and other bone-derived cells to the pre-metastatic niche. If the mouse data is transferable to humans, and we have reasons to think it will be, we really believe way may have found an effective way to treat human disease."
Source: Stanford University Medical Center

[Rich66]

Cancer Cell. 2009 Jan 6;15(1):35-44.
Hypoxia-induced lysyl oxidase is a critical mediator of bone marrow cell recruitment to form the premetastatic niche.

Erler JT, Bennewith KL, Cox TR, Lang G, Bird D, Koong A, Le QT, Giaccia AJ.
Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA.
Tumor cell metastasis is facilitated by "premetastatic niches" formed in destination organs by invading bone marrow-derived cells (BMDCs). Lysyl oxidase (LOX) is critical for premetastatic niche formation. LOX secreted by hypoxic breast tumor cells accumulates at premetastatic sites, crosslinks collagen IV in the basement membrane, and is essential for CD11b+ myeloid cell recruitment. CD11b+ cells adhere to crosslinked collagen IV and produce matrix metalloproteinase-2, which cleaves collagen, enhancing the invasion and recruitment of BMDCs and metastasizing tumor cells. LOX inhibition prevents CD11b+ cell recruitment and metastatic growth. CD11b+ cells and LOX also colocalize in biopsies of human metastases. Our findings demonstrate a critical role for LOX in premetastatic niche formation and support targeting LOX for the treatment and prevention of metastatic disease.

PMID: 19111879 [PubMed - indexed for MEDLINE]




Int J Mol Med. 2010 Feb;25(2):271-80.
Influence of LOX/COX inhibitors on cell differentiation induced by all-trans retinoic acid in neuroblastoma cell lines.

Redova M, Chlapek P, Loja T, Zitterbart K, Hermanova M, Sterba J, Veselska R.
Laboratory of Tumor Biology and Genetics, Institute of Experimental Biology, School of Science, Masaryk University, 61137 Brno, Czech Republic.
We investigated the possible modulation by LOX/ COX inhibitors of all-trans retinoic acid (ATRA)-induced cell differentiation in two established neuroblastoma cell lines, SH-SY5Y and SK-N-BE(2). Caffeic acid, as an inhibitor of 5-lipoxygenase, and celecoxib, as an inhibitor of cyclooxygenase-2, were chosen for this study. The effects of the combined treatment with ATRA and LOX/COX inhibitors on neuroblastoma cells were studied using cell morphology assessment, detection of differentiation markers by immunoblotting, measurement of proliferation activity, and cell cycle analysis and apoptosis detection by flow cytometry. The results clearly demonstrated the potential of caffeic acid to enhance ATRA-induced cell differentiation, especially in the SK-N-BE(2) cell line, whereas application of celecoxib alone or with ATRA led predominantly to cytotoxic effects in both cell lines. Moreover, the higher sensitivity of the SK-N-BE(2) cell line to combined treatment with ATRA and LOX/COX inhibitors suggests that cancer stem cells are a main target for this therapeutic approach. Nevertheless, further detailed study of the phenomenon of enhanced cell differentiation by expression profiling is needed.

PMID: 20043138 [PubMed - in process]

[Rich66]

J Biol Chem. 2009 May 29;284(22):15206-14. Epub 2009 Mar 18.
Inhibition of tumor cell motility by the interferon-inducible GTPase MxA.

Mushinski JF, Nguyen P, Stevens LM, Khanna C, Lee S, Chung EJ, Lee MJ, Kim YS, Linehan WM, Horisberger MA, Trepel JB.
Laboratory of Cancer Biology and Genetics, Medical Oncology Branch, Pediatric Oncology Branch, and Urologic Oncology Branch, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA.
To identify pathways controlling prostate cancer metastasis we performed differential display analysis of the human prostate carcinoma cell line PC-3 and its highly metastatic derivative PC-3M. This revealed that a 78-kDa interferon-inducible GTPase, MxA, was expressed in PC-3 but not in PC-3M cells. The gene encoding MxA, MX1, is located in the region of chromosome 21 deleted as a consequence of fusion of TMPRSS2 and ERG, which has been associated with aggressive, invasive prostate cancer. Stable exogenous MxA expression inhibited in vitro motility and invasiveness of PC-3M cells. In vivo exogenous MxA expression decreased the number of hepatic metastases following intrasplenic injection. Exogenous MxA also reduced motility and invasiveness of highly metastatic LOX melanoma cells. A mutation in MxA that inactivated its GTPase reversed inhibition of motility and invasion in both tumor cell lines. Co-immunoprecipitation studies demonstrated that MxA associated with tubulin, but the GTPase-inactivating mutation blocked this association. Because MxA is a highly inducible gene, an MxA-targeted drug discovery screen was initiated by placing the MxA promoter upstream of a luciferase reporter. Examination of the NCI diversity set of small molecules revealed three hits that activated the promoter. In PC-3M cells, these drugs induced MxA protein and inhibited motility. These data demonstrate that MxA inhibits tumor cell motility and invasion, and that MxA expression can be induced by small molecules, potentially offering a new approach to the prevention and treatment of metastasis.

PMID: 19297326 [PubMed - indexed for MEDLINE]




J Neurooncol. 2007 Mar;82(1):91-3. Epub 2006 Sep 26.

A lipoxygenase inhibitor in breast cancer brain metastases.(Boswellia serrata)

PDF(3pgs): http://www.springerlink.com/content/...2/fulltext.pdf

Flavin DF.
Foundation for Collaborative Medicine and Research, Greenwich, CT 06831, USA. Dana_FK@hotmail.com
The complication of multiple brain metastases in breast cancer patients is a life threatening condition with limited success following standard therapies. The arachidonate lipoxygenase pathway appears to play a role in brain tumor growth as well as inhibition of apoptosis in in-vitro studies. The down regulation of these arachidonate lipoxygenase growth stimulating products therefore appeared to be a worthwhile consideration for testing in brain metastases not responding to standard therapy.
Boswellia serrata, a lipoxygenase inhibitor was applied for this inhibition. Multiple brain metastases were successfully reversed using this method in a breast cancer patient who had not shown improvement after standard therapy. The results suggest a potential new area of therapy for breast cancer patients with brain metastases that may be useful as an adjuvant to our standard therapy.

PMID: 17001517 [PubMed - indexed for MEDLINE]

Quote:

The patient was started on capecitabine and given radiation therapy of 44 Gy with no improvement seen for the first 2 weeks. The severity and inoperability of
her condition made using an additional therapy a consideration. An oxidoreductase [plant lipoxygenases (LOX)] inhibitor was applied (Boswellia serrata) which has no known major side effects. The enzyme, LOX, arachidonate: oxygen oxidoreductase (form mammalian LOX) is thought to be responsible for edema in primary brain tumors and present ongoing studies on LOX inhibitors in Germany indicate an overall improvement in response to radiation therapy as well as a decrease in some primary brain tumors seen even without radiation. Although it was not known if LOX inhibitors would be helpful in breast cancer brain metastases it was worth considering in this case since she had not only several large tumors but also additional extremely small tumors scattered throughout the brain. She was immediately placed on a LOX inhibitor. Following 10 weeks of therapy, the patient was scheduled for a new CT since her CEA and Ca 15–3 tumor markers had increased. The CT results showed a complete disappearance of all signs of metastases in her brain (Fig. 2a, b).
The patient has been maintained on the LOX inhibitor,

Boswellia serrata, 3 · 800 mg/day

with no new signs of cerebral involvement of her breast cancer for over 4 years, however, there have recently been skeletal metastases which most likely indicates LOX has a limited skeletal tissue involvement in cancer.


J Immunol. 2006 Mar 1;176(5):3127-40.
Acetyl-11-keto-beta-boswellic acid potentiates apoptosis, inhibits invasion, and abolishes osteoclastogenesis by suppressing NF-kappa B and NF-kappa B-regulated gene expression.

Takada Y, Ichikawa H, Badmaev V, Aggarwal BB.
Cytokine Research Section, Department of Experimental Therapeutics, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA.
Acetyl-11-keto-beta-boswellic acid (AKBA), a component of an Ayurvedic therapeutic plant Boswellia serrata, is a pentacyclic terpenoid active against a large number of inflammatory diseases, including cancer, arthritis, chronic colitis, ulcerative colitis, Crohn's disease, and bronchial asthma, but the mechanism is poorly understood. We found that AKBA potentiated the apoptosis induced by TNF and chemotherapeutic agents, suppressed TNF-induced invasion, and inhibited receptor activator of NF-kappaB ligand-induced osteoclastogenesis, all of which are known to require NF-kappaB activation. These observations corresponded with the down-regulation of the expression of NF-kappaB-regulated antiapoptotic, proliferative, and angiogenic gene products. As examined by DNA binding, AKBA suppressed both inducible and constitutive NF-kappaB activation in tumor cells. It also abrogated NF-kappaB activation induced by TNF, IL-1beta, okadaic acid, doxorubicin, LPS, H2O2, PMA, and cigarette smoke. AKBA did not directly affect the binding of NF-kappaB to the DNA but inhibited sequentially the TNF-induced activation of IkappaBalpha kinase (IKK), IkappaBalpha phosphorylation, IkappaBalpha ubiquitination, IkappaBalpha degradation, p65 phosphorylation, and p65 nuclear translocation. AKBA also did not directly modulate IKK activity but suppressed the activation of IKK through inhibition of Akt. Furthermore, AKBA inhibited the NF-kappaB-dependent reporter gene expression activated by TNFR type 1, TNFR-associated death domain protein, TNFR-associated factor 2, NF-kappaB-inducing kinase, and IKK, but not that activated by the p65 subunit of NF-kappaB. Overall, our results indicated that AKBA enhances apoptosis induced by cytokines and chemotherapeutic agents, inhibits invasion, and suppresses osteoclastogenesis through inhibition of NF-kappaB-regulated gene expression.

Bosellia serrata-induced apoptosis is related with ER stress and calcium release.

Cancer Res. 2009 Jul 15;69(14):5893-900. Epub 2009 Jun 30.
Acetyl-11-keto-beta-boswellic acid inhibits prostate tumor growth by suppressing vascular endothelial growth factor receptor 2-mediated angiogenesis.

Pang X, Yi Z, Zhang X, Sung B, Qu W, Lian X, Aggarwal BB, Liu M.
Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China.
The role of angiogenesis in tumor growth and metastasis is well established. Identification of a small molecule that blocks tumor angiogenesis and is safe and affordable has been a challenge in drug development. In this study, we showed that acetyl-11-keto-beta-boswellic acid (AKBA), an active component from an Ayurvedic medicinal plant (Boswellia serrata), could strongly inhibit tumor angiogenesis. AKBA suppressed tumor growth in the human prostate tumor xenograft mice treated daily (10 mg/kg AKBA) after solid tumors reached approximately 100 mm(3) (n = 5). The inhibitory effect of AKBA on tumor growth was well correlated with suppression of angiogenesis. When examined for the molecular mechanism, we found that AKBA significantly inhibited blood vessel formation in the Matrigel plug assay in mice and effectively suppressed vascular endothelial growth factor (VEGF)-induced microvessel sprouting in rat aortic ring assay ex vivo. Furthermore, AKBA inhibited VEGF-induced cell proliferation, chemotactic motility, and the formation of capillary-like structures from primary cultured human umbilical vascular endothelial cells in a dose-dependent manner. Western blot analysis and in vitro kinase assay revealed that AKBA suppressed VEGF-induced phosphorylation of VEGF receptor 2 (VEGFR2) kinase (KDR/Flk-1) with IC(50) of 1.68 micromol/L. Specifically, AKBA suppressed the downstream protein kinases of VEGFR2, including Src family kinase, focal adhesion kinase, extracellular signal-related kinase, AKT, mammalian target of rapamycin, and ribosomal protein S6 kinase. Our findings suggest that AKBA potently inhibits human prostate tumor growth through inhibition of angiogenesis induced by VEGFR2 signaling pathways.

[Rich66]

PLoS One. 2009;4(5):e5620. Epub 2009 May 19.
The lysyl oxidase inhibitor, beta-aminopropionitrile, diminishes the metastatic colonization potential of circulating breast cancer cells.

Bondareva A, Downey CM, Ayres F, Liu W, Boyd SK, Hallgrimsson B, Jirik FR.
Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada.
Lysyl oxidase (LOX), an extracellular matrix remodeling enzyme, appears to have a role in promoting breast cancer cell motility and invasiveness. In addition, increased LOX expression has been correlated with decreases in both metastases-free, and overall survival in breast cancer patients. With this background, we studied the ability of beta-aminopropionitrile (BAPN), an irreversible inhibitor of LOX, to regulate the metastatic colonization potential of the human breast cancer cell line, MDA-MB-231. BAPN was administered daily to mice starting either 1 day prior, on the same day as, or 7 days after intracardiac injection of luciferase expressing MDA-MB-231-Luc2 cells. Development of metastases was monitored by in vivo bioluminescence imaging, and tumor-induced osteolysis was assessed by micro-computed tomography (microCT). We found that BAPN administration was able to reduce the frequency of metastases. Thus, when BAPN treatment was initiated the day before, or on the same day as the intra-cardiac injection of tumor cells, the number of metastases was decreased by 44%, and 27%, and whole-body photon emission rates (reflective of total tumor burden) were diminished by 78%, and 45%, respectively. In contrast, BAPN had no effect on the growth of established metastases. Our findings suggest that LOX activity is required during extravasation and/or initial tissue colonization by circulating MDA-MB-231 cells, lending support to the idea that LOX inhibition might be useful in metastasis prevention.

PMID: 19440335 [PubMed - indexed for MEDLINE]

[Rich66]

Planta Med. 2000 Mar;66(2):110-3.
Concentration-dependent potentiating and inhibitory effects of Boswellia extracts on 5-lipoxygenase product formation in stimulated PMNL.

Safayhi H, Boden SE, Schweizer S, Ammon HP.
Department of Pharmacology, University of Tuebingen, Germany. hasan.safayhi@uni-tuebingen.de
Preparations from the gum of Boswellia spec. have been used in the traditional medicine for the treatment of inflammatory diseases. Extracts from B. serrata gum were shown to inhibit leukotriene biosynthesis by impairing the 5-lipoxygenase (5-LO) activity. In order to identify the minimal effective concentrations of extracts in vitro we studied the effects of ethanolic extracts from commercially available resins from two regions (B. serrata gum from India and Olibanum in granis from Arabia) on the 5-LO product formation from endogenous substrate in calcium and ionophore stimulated neutrophils in a defined concentration range. Both extracts inhibited 5-LO product formation in vitro in concentrations greater than 10 to 15 micrograms/ml as reported previously for an ethanolic B. serrata extract. In contrast, lower concentrations of extracts (1 to 10 micrograms/ml) even potentiated 5-LO product formation, especially the biosynthesis of 5(S)-HETE. The in vitro data underline the major importance of drug standardization when Boswellia resin containing preparations are used for the treatment of diseases.

PMID: 10763581 [PubMed - indexed for MEDLINE]


Biochem Pharmacol. 2008 Jun 1;75(11):2112-21. Epub 2008 Mar 15.
Inhibitory effect of acetyl-11-keto-beta-boswellic acid on androgen receptor by interference of Sp1 binding activity in prostate cancer cells.

Yuan HQ, Kong F, Wang XL, Young CY, Hu XY, Lou HX.
Department of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan, Shandong 250012, China.
Androgen receptor (AR)-mediated signaling is crucial for the development and progression of prostate cancer (PCa). Naturally occurring phytochemicals that target the AR signaling offer significant protection against this disease. Acetyl-11-keto-beta-boswellic acid (AKBA), a compound isolated from the gum-resin of Boswellia carterii, caused G1-phase cell cycle arrest with an induction of p21(WAF1/CIP1), and a reduction of cyclin D1 as well in prostate cancer cells. AKBA-mediated cellular proliferation inhibition was associated with a decrease of AR expression at mRNA and protein levels. Furthermore, the functional biomarkers used in evaluation of AR transactivity showed suppressions of prostate-specific antigen promoter-dependent and androgen responsive element-dependent luciferase activities. Additionally, down-regulation of an AR short promoter mainly containing a Sp1 binding site suggested the essential role of Sp1 for the reduction of AR expression in cells exposed to AKBA. Interruption effect of AKBA on Sp1 binding activity but not Sp1 protein levels was further confirmed by EMSA and transient transfection with a luciferase reporter driven by three copies of the Sp1 binding site of the AR promoter. Therefore, anti-AR properties ascribed to AKBA suggested that AKBA-containing drugs could be used for the development of novel therapeutic chemicals.

PMID: 18430409 [PubMed - indexed for MEDLINE]

[Ellie F]

Hi
A lot of alternative practitioners recommend eating a diet rich in natural COX and LOX inhibiting foods.I suppose we are back to the whole question if synergy again?

Ellie