ENZYMES AS TARGETS FOR CANCER THERAPY

ENZYMES AS TARGETS FOR CANCER THERAPY

Shiwani Patil and N. Saraswathy^*

Shobhaben Pratapbhai Patel School of Pharmacy and Technology Management, SVKM`s NMIMS, Vile Parle (W), Mumbai - 400056, Maharashtra, India.

ABSTRACT: Cancer is a deliberating disease affecting people worldwide. Treatment of cancer has become a number one priority among medical specialists and different modes of treatment are being pursued. Various factors are involved in the proliferation of cancer thereby complicating its treatment. Certain enzymes or protein products within the cell can be up-regulated or down-regulated as the cancer progresses inside the tissue. In order to treat cancer, enzymes which play a key role in the disease can be targeted. These enzymes include cysteine cathepsins and matrix metalloproteinases. Cysteine cathepsins are a group of enzymes that are involved in degradation of the surrounding cell environment of cancer cells. The surrounding healthy cells are thereby invaded and destroyed by cancer cells. Hence they cause localized spreading and growth of cancer cells. Matrix metalloproteinase are mainly involved in metastasis of these cancer cells. They help in angiogenesis surrounding the cancer tissue thus providing nutrition to cells and proliferation via the blood stream. Hence both enzymes has a vital role in proliferation of cancer cells into body. These enzymes can be targeted for treatment of cancer and can act as a supplementary process to the cancer Containment, which in turn can increase the chances of survival. Various drugs are under trial for this form of therapy.

Cancer, Tumour, Matrix metalloproteinase, Cysteine cathepsins, Metastasis, Angiogenesis

INTRODUCTION: Cancer is a group of disease, where there is abnormal cell growth which have the potential to invade other parts of the body. Cancer cells can form a tumour which invades the local tissue and cancer has been one of the leading causes of death. The most common cancers are breast cancer, lung and bronchus cancer, prostate cancer, colon and rectum cancer, bladder cancer, melanoma of the skin, non-Hodgkin lymphoma, thyroid cancer, kidney and renal pelvis cancer, leukaemia, endometrial cancer, and pancreatic cancer.

There are over 100 different known cancers that affect humans ¹. In 2012 about 14.1 million new cases of cancer occurred globally. It caused about 8.2 million deaths or 14.6% of all human deaths ². The cells of a tumour descend from a common ancestral cell that at some point became mutant. This program of multiple mutations, accumulate throughout the life of the host and each mutation is passed on to the daughter cells. For cancer to rise, a series of critical mutations must occur, usually through mutations in specific classes.

To control normal functioning of a cell, regulatory functions are required. However in a cancer cell, these regulatory functions are diminished or lost altogether. Because of their altered regulation, the cells have distinguished features other than that of normal cells and produce different proteins altogether. The loss of such regulation is mainly due to gene alteration in these cells.

These mutations can arise from various factors such as viruses, oncogenes, mutagenic chemical exposure, carcinogens and environmental factors. It is because of such mutations that the formation and regulation of certain proteins can be altered leading to higher levels of same in a cancer cell. Various proteins involved in cancer include matrix metalloproteinase, cysteine cathepsins and serine proteases.

Matrix Metalloproteinase: The MMPs are a family of zinc-containing endopeptidases that degrade various components of the extracellular matrix (ECM) ³. They are part of larger family of proteases ⁴. MMPs include the requirement of zinc in their catalytic site for activity and their synthesis as inactive zymogens that generally needed to be proteolytically cleaved to be active. Normally the MMPs are expressed only when and where needed for tissue remodelling. MMP expression and activity are regulated at several levels. In most cases, MMPs are not synthesized by the cell until needed. Transcription can be induced by various signals including cytokines, growth factors, and mechanical stress ³. However, uncharacteristic expression of various MMPs has been correlated with pathological conditions such as periodontitis, rheumatoid arthritis tumour cell invasion and metastasis ⁵.

20 different members of the MMP family have been identified, and they are sub-grouped based on their structures ³. Each member consists at least of a signal peptide, prodomain, band catalytic domain. MMPs containing only the minimal domain are referred to as matrilysins (MMP-7 and -26). They are classified based on the presence of different domains. The most common structures for secreted MMPs are collagenases, and stromelysins (MMP-1, -3, -8, -10, -12, -13, -19, and -20) and the gelatinases (MMP-2 and -9) ⁶.

MMPs participate in angiogenesis by degrading basement membrane and other ECM components, allowing endothelial cells to detach and migrate into new tissue. In addition, MMP degradation of ECM components generates fragments with accessible integrin binding sites, triggering integrin intracellular signalling. By directly binding to 3, MMP-2 may itself initiate integrin signalling and thereby contributing to endothelial cell survival and proliferation ⁷. MMPs have both pro- and antiangiogenic functions. On the whole, however, MMPs are required for angiogenesis ⁸.

Role of Matrix Metalloproteinase in Cancer: During development of cancer, tumour cells interact with the tumour microenvironment in ECM, such as the growth factors and cytokines associated with ECM, as well as surrounding endothelial cells ⁹. Four traits of cancer that include migration, invasion, metastasis and angiogenesis are dependent on this surrounding microenvironment. MMPSs play an important role as they degrade various cell adhesion molecules, thereby increasing cell–cell and cell–ECM interactions.

Expression of MMPs has been found to be upregulated in all type of human cancer and correlates with advanced stage, invasive and metastatic ^{10, 11}. Different MMPs have different roles at various stages of cancer. For cancer cells to continue to grow and start migrating, it is necessary to form new blood vessels. The first step in this process is to eliminate the physical barriers by ECM degradation and, subsequently, to generate pro-angiogenic factors. Up-regulation of MMP expression, in particular the gelatinases, degrade basement membrane components, thereby permitting the tumour cells to invade into the adjacent stroma and to break down the basement membranes associated with capillaries and lymphatic vessels allowing tumour cells to enter the circulation ¹². MMPs are involved in cell migration by removing sites of adhesion which exposes new binding sites by cleaving cell-cell or cell-matrix receptors ⁶¹. MMP-9 participates in the angiogenic switch because it increases the bioavailability of important factors in this process, such as the vascular endothelial growth factor (VEGF), which is the most potent mediator of tumour vasculature, and basic fibroblast growth factor (bFGF), by degradation of extracellular components, such as collagen type IV, XVIII and perlecan, respectively ^{13, 14}.

Members of the MMP and ADAM families can release the cell-membrane- precursors of several growth factors, such as insulin-like growth factors (IGFs) and the epidermal growth factor receptor (EGFR) ligands that promote proliferation. Several MMPs (MMP-1, -2, -3, -7, -9 -11 and -19) and ADAM12 cleave IGF-binding proteins that regulate the bioavailability of the growth factor ¹⁵. EGFR, mediator of cell proliferation, is implicated in cancer progression because it is over expressed in more than one-third of all solid tumours ¹⁶.

Matrix-degrading enzymes confer both apoptotic and anti-apoptotic actions. MMPs and ADAMs, especially MMP-7 and ADAM10, confer anti-apoptotic signals to cancer cells by cleaving Fas ligand, a transmembrane stimulator of the death receptor Fas, from the cell surface. This proteolytic activity inactivates Fas receptor and induces resistance to apoptosis and chemo-resistance to the cancer cells or promotes apoptosis to the neighbouring cells depending on the system ¹⁷.

Moreover, proteolytic shedding of tumour associated major histocompatibility proteins complex class-I related proteins by ADAM17 may suppress natural killer (NK) cell-mediated cytotoxicity toward cancer cells ¹⁸. Notably, MMPs may contribute to the anti-apoptotic effect by activating indirectly the serine ⁄ threonine kinase Akt ⁄ protein kinase B through the signalling cascades of EGFR and IGFR ^{16, 17}. MMPs also promote apoptosis, most likely indirectly by changing the ECM composition; for example, by cleaving laminin, which influences integrin signalling ¹⁹.

Cysteine Cathepsins: Cysteine cathepsins are enzymes which belong to the papain subfamily of cysteine proteases ²⁰. They function at a lower pH and are distinguished by their structure, catalytic mechanism, and which proteins they cleave. They are mostly endopeptidases located in endolsysomal vesicles intracellularly.

However some do function extracellularly like cathepsins K which is secreted into the resorptive pit between osteoclasts and bone ²¹. There are 11 human cysteine cathepsins, which primarily function as endopeptidases within endolysosomal compartments. Specific cysteine cathepsins have extracellular functions, for example, cathepsin S in MHC (major histocompatibility complex) class II antigen presentation ²². Multiple mechanisms increase cysteine cathepsin expression in tumours, including amplification of the cathepsin B gene and alternative splicing of cathepsin L and B transcripts. Increases in expression occur both in tumour cells and tumour-associated cells such as macrophages, endothelial cells and myo-epithelial cells. In tumours these enzymes can be secreted, bind to specific regions on the cell membrane and are localized in endolysosomal vesicles. Their substrates and functions differ depending on their location. Causal roles for cysteine cathepsins in cancer have been demonstrated by pharmacological and genetic techniques.

This includes functional down regulation of cysteine cathepsin activity by increasing expression of endogenous inhibitors and administration of small-molecule cysteine protease inhibitors. Contributory roles of cysteine cathepsins in cancer have also been identified in regard to intracellular matrix degradation following endocytosis of collagens by urokinase plasminogen activator receptor-associated protein (uPARAP). Contributory roles for specific cysteine cathepsins in cancer have been demonstrated by down regulating their expression or crossing mouse models of cancer with mice in which the cysteine cathepsin has been genetically ablated. These studies have identified roles for cysteine cathepsins in both tumour cells and tumour-associated cells such as endothelial cells and macrophages ²³.

Cysteine cathepsins were thought to function intracellularly within lysosomal vacuoles. However cathepsin K, B and L are found to be present both intracellularly and extracellularly. Studies on mice that are deficient in these 3 cathepsins have shown that all three function, both extracellularly and intracellularly to liberate thyroglobulin ²⁴.

Functions of these cysteine cathepsinsin cancers are not yet well defined nor are their roles in tumour cells and the tumour-associated cells that contribute to neoplastic progression are known Since cysteine cathepsins are secreted and localized in lysosomal vesicles their enzymatic substrates and functions might change along with their localization. Cysteine cathepsins are used cleavage of extracellular matrix proteins such as laminin ^{25, 26}, type IV collagen62 and tenascin C64, cell-adhesion proteins such as E-cadherin ²⁷, activation of pro-enzymes such as pro-urokinase plasminogen activator (prouPA) ^{28, 29}. Degradation of extracellular matrix protein such as collagens ^{30, 31} also occurs intracellularly.

Up Regulation During Cancer: As the genes coding for various proteins get mutated in cancer various proteins get up regulated while others get down regulated. Gene amplifications may take place for the gene coding of cysteine cathepsin, for example over expression of cathepsin B in adenocarcinomas of the oesophagus ³² and gastric cardia ³³.

Transcript variants are tumour cells for cathepsins B and L, arising from the use of alternative promoters ^{34, 35} and alternative splicing ^{36, 37}. In these cells shorter transcripts are formed which are easily translated and hence lead to their over expression ^{38, 39}. These transcripts are however regulated by various factors and require further study. For example low levels of expression of cathepsin L in a B-cell lymphoma line are due to methylation of a CpG island in the cathepsin L promoter ⁴⁰.

However up regulation mechanism is not known for all types of cathepsins. Higher levels of cathepsin V is used as a diagnosis tool for detection of breast carcinomas ⁴¹. The over expression of a certain cysteine cathepsins is different in different types of cell. This over expression is found mostly in tumour cells and tumour associated cells. For example high levels of cysteine cathepsins in myoepithelial cells, associated with ductal carcinoma in situ, for cathepsins F, K and L ⁴², and in the endothelial cells for cathepsin B ⁴³.

Role of Cysteine Cathepsins within Cells: Cysteine cathepsins are mainly involved in proteolysis. However in neoplastic progression it is known that pericellular proteolysis occurs. Inactive precursor forms of a number of cysteine cathepsins are secreted from both transformed and tumour cells ^{44, 45}. Active forms are also released from cells ⁴⁶ and activated macrophages ^{47, 48}. Proteolysis by such cathepsins leads to tumour invasion to neighbouring cells. Intracellular proteolysis in tumour cells, just like pericellular proteolysis, involves both cysteine cathepsins and uPA/uPAR. The two proteolytic systems are networked through uPARAP (urokinase plasminogen activator receptor-associated protein)/Endo180, a member of the macrophage mannose receptor family ⁴⁹ uPARAP forms a trimolecular complex with pro-uPA and uPAR and is essential for the cellular uptake of collagen and its subsequent degradation in lysosomes by cysteine cathepsins ^{50, 51}. This is an important pathway of extracellular matrix degradation during mammary tumour progression ³¹. Intracellular degradation of collagens in tumours has also been observed within tumour cell lysosomes, for example, in colon tumour cells ⁵².

Individual cathepsin is found in higher levels in different tumour cells ⁵³. For example, cathepsin B has been shown to be assisting in migration and invasion of human osteosarcoma and glioblastoma cells ^{54, 55}. Cathepsin L is found to have a role in migration and invasion of human osteosarcoma cells ⁵⁶ and cathepsin X in migration of human gastric carcinoma cells ⁵⁷.

These indicate role of cathepsin B in tumour development and progression ⁵⁸, but also indicate smaller roles of cathepsin L and X. Cathepsins B and S have shown to affect the ability of tumours to induce angiogenesis. This has been shown for cathepsin B in glioblastomas ⁵⁹, cathepsins B and S in RIP1–Tag2 pancreatic tumours ^{60, 61} and cathepsin S in brain tumor ⁶².

Cysteine cathepsins also have roles in tumour associated cells. Genetic ablation of various cathepsins has been found to contribute to metastasis. Genetic ablation of cathepsin B in the MMTV-PyMT model revealed a role for macrophage cathepsin B in experimental lung metastasis of these tumours ⁶³.

Functional down regulation of cysteine cathepsin activity by increasing the expression of the endogenous inhibitors of these enzymes has confirmed roles proteases in cancer. Studies in which cystatin C, cystatin M and stefin/cystatin A were over expressed in tumour cell lines ^{64, 65} have shown that cysteine cathepsins have functional roles in growth, invasion and metastasis of tumour cells of epithelial and mesenchymal origins. Alternatively, silencing expression of inhibitor cystatin M in a metastatic oral cancer cell line results in increased migration and invasion as it caused increase in cysteine cathepsin activity ⁶⁶. These studies indicate   the proteolytic activity of the cysteine cathepsin family is involved in the malignant phenotype of tumour cells and tumour-associated endothelial cells.

FIG. 1: THE FIGURE DENOTE THE WORKING OF THE TWO ENZYMES IN CONJUNCTION IN A TISSUE AND HOW THEY PROMOTE CANCER. CATHEPSINS DISSOLVE THE SURROUNDING CELLS AND OCCUPY THEIR PLACE. METALLOPROTEINASE ENSURE THE PROLIFERATION AND RELEASED IN BLOOD VESSELS TO INCREASE THE BLOOD FLOW TO CANCER TISSUE BY ANGIOGENESIS

Current Strategies for Treatment: All the enzymes mentioned can be targeted for treatment of cancer. Although it would be ineffective as sole treatment, but when provided as secondary treatment it can increase the chances of survival. Currently there need to be more study available on such treatment regimes. Recent advances in these fields seem promising.

Several generations of synthetic MMPIs were tested in phase III clinical trials in humans, including peptidomimetics, nonpeptidomimetics inhibitors and tetracycline derivatives, which target MMPs in the extracellular space ⁶⁷. In addition, various natural compounds have been identified as inhibiting MMPs ⁶⁸. The first generation of MMPIs introduced comprised the peptidomimetic. These pseudopeptide derivatives mimic the structure of collagen at the MMP cleavage site, functioning as competitive inhibitors, and chelating the zinc ion present at the activation site ¹¹. These include drugs like batimastat and marismastat. To improve specificity and oral bioavailability, the nonpeptidomimetic MMPIs were synthesized which include prinomastat. However musculoskeletal toxicity has also been reported in clinical trials with the drug ⁶⁹. Another generation of MMPIs, tetracycline derivatives, inhibit both the enzymatic activity and the synthesis of MMPs via blocking gene transcription.

Currently only Food and Drug Administration approved MMPI are used for the prevention of periodontitis, whereas metastat has entered phase II trials for Kaposi’s sarcoma and brain tumors ⁷⁰.

Merck and Co., has developed a Cathepsin K inhibitor which is currently in Phase 3 clinical trials by the name of Odanacatib⁷¹. Velcura Therapeutics, Inc. has also developed a highly selective cathepsin K inhibitor named VEL-0230, which is in on-going trials in humans and rats ⁷². Folkman and colleagues have targeted intracellular cathepsin B in neovessels endothelial cells in order to increase the efficacy of angiogenesis inhibitors ⁷³.

Therapeutic agents designed for activation at the tumour cell surface by cathepsin B have proved efficacious. Two groups have conjugated cathepsin B-cleavable linkers to pore-forming toxins from staphylococcal α-haemolysin ⁷⁴ and a sea anemone ⁷⁵. A similar strategy has been used to develop prodrugs of doxorubicin ⁷⁶.

CONCLUSION: Although there is no definitive treatment option available for cancer, different options are available. Targeting of these enzymes alone cannot help treat the cancer. However these treatment options can be used in conjunction with current treatment options to provide higher chances of cure and recovery. These enzymes show a promising target for cancer treatment and can be used effectively. However further testing needs to be done to understand the underlying mechanism of the enzymes. Data and research need to be generated on the safety and efficacy of the drugs using this route. With greater efforts the future of cancer treatment can be brighter.

ACKNOWLEDGEMENT: The authors are thanking the authorities of SPPSPTM, NMIMS for valuable support and facilities provided.

CONFLICT OF INTEREST: the authors report no conflict of interest.

REFERENCES:

1. https://www.cancer.gov/about-cancer/understanding/what-is-cancer - National Cancer Institute. Retrieved, 2016.
2. World Health Organization: World Cancer Report 2014. World Health Organization, 2014.
3. Overall C. M., and Lopez-Otın, C: Strategies for MMP inhibition in cancer: Innovations for the post-trial era. Nat. Rev. Cancer 2002; 2: 657–672.
4. Page-McCaw, A.; Ewald, A. J.; Werb, Z: Matrix metalloproteinase and the regulation of tissue remodelling. Nature Rev. Mol. Cell Biol. 2007; 8: 221-233.
5. Woessner, J. F., Jr.: Matrix metalloproteinases and their inhibitors in connective tissue remodelling. FASEB J. 1991; 5: 2145–2154.
6. Joyce E. Rundhaug,: Matrix Metalloproteinases, Angiogenesis, and Cancer: Commentary re: A. C. Lockhart et al., Reduction of Wound Angiogenesis in Patients Treated with BMS-275291, a Broad Spectrum Matrix Metalloproteinase Inhibitor. Clin. Cancer, Res. 2003; 9(2): 551-554.
7. Stetler-Stevenson WG: Matrix metalloproteinases in angiogenesis: a moving target for therapeutic intervention. J. Clin. Investig. 1999; 103: 1237–1241.
8. Naglich, J. G., Jure-Kunkel, M., Gupta, E., Fargnoli, J., Henderson, A. J., Lewin, A. C., Talbott, R., Baxter, A., Bird, J., Savopoulos, R., Wills, R., Kramer, R. A., and Trail, P. A.: Inhibition of angiogenesis and metastasis in two murine models by the matrix metalloproteinase inhibitor. BMS-275291. Cancer Res. 2001; 61: 8480–8485.
9. Murphy G: The ADAMs signalling scissors in the tumour microenvironment. Nat Rev Cancer 2008; 8: 932– 941.
10. Coussens, L. M., Fingleton, B., and Matrisian, L. M.: Matrix metalloproteinase inhibitors and cancer: trials and tribulations. Science (Wash. DC) 2002; 295: 2387–2392.
11. Egeblad, M., and Werb, Z.: New functions for the matrix metalloproteinases in cancer progression. Nat. Rev. Cancer 2002; 2: 161–174.
12. Chambers, A. F., and Matrisian, L. M.: Changing views of the role of matrix metalloproteinases in metastasis. J. Natl. Cancer Inst. (Bethesda) 1997; 89: 1260–1270.
13. Bergers G, Brekken R, McMahon G, Vu TH, Itoh T, Tamaki K, Tanzawa K, Thorpe P, Itohara S, Werb Z et al.: Matrix metalloproteinase-9 triggers the angiogenic switch during carcinogenesis. Nat Cell Biol. 2000; 2: 737–744.
14. Iozzo RV, Zoeller JJ and Nystro¨m A: Basement membrane proteoglycans: modulators par excellence of cancer growth and angiogenesis. Mol Cells, 2009; 27: 503–513.
15. Loechel F, Fox JW, Murphy G, Albrechtsen R and Wewer UM; ADAM 12-S Cleaves IGFBP-3 and IGFBP-5 and Is Inhibited by TIMP-3. Biochem Biophys Res Commun. 2000; 278(3): 511-5.
16. Gialeli CH, Kletsas D, Mavroudis D, Kalofonos HP, Tzanakakis GN and Karamanos NK: Targeting epidermal growth factor receptor in solid tumors: critical evaluation of the biological importance of therapeutic monoclonal antibodies. Curr Med Chem. 2009; 16: 3797–3804.
17. Strand S, Vollmer P, Van De Abeelen L, Gottfried D, Alla V, Heid H, Kuball J, Theobald M, Galle PR and Strand D: Cleavage of CD95 by matrix metalloproteinase- 7 induces apoptosis resistance in tumor cells. Oncogene. 2004; 23: 3732–3736.
18. Waldhauer I, Goehlsdorf D, Gieseke F, Weinschenk T, Wittenbrink M, Ludwig A, Stevanovic S, Rammensee HG and Steinle A: Tumor associated MICA is shed by ADAM proteases. Cancer Res 2008; 68: 6368–6376.
19. Sympson CJ, Talhouk RS, Alexander CM, Chin JR, Clift SM, Bissell MJ and Werb Z: Targeted expression of stromelysin-1 in mammary gland provides evidence for a role of proteinases in branching morphogenesis and the requirement for an intact basement membrane for tissue specific gene expression. J Cell Biol. 1994; 125: 681–693.
20. Rawlings, N. D., Morton, F. R. and Barrett, A. J.: MEROPS the peptidase database. Nucleic Acids Res. 2006; 34: D270–D272.
21. Xia L,Kilb J, Wex H, Li Z, Lipyansky A, Breuil V, Stein L, Palmer JT, Dempster DW, and Brömme D.: Localization of rat cathepsin K in osteoclasts and resorption pits: inhibition of bone resorption and cathepsin K-activity by peptidyl vinyl sulfones. Biol. Chem. 1999; 380: 679–687.
22. Shi GP,Villadangos JA, Dranoff G, Small C, Gu L, Haley KJ, Riese R, Ploegh HL, Chapman HA.: Cathepsin S required for normal MHC class II peptide loading and germinal center development. Immunity 1999; 10:197–206.
23. Mohamed M M and Bonnie F. Sloane: Cysteine cathepsins: multifunctional enzymes in cancer. Nature Reviews Cancer. 2006; 6:764-775.
24. Friedrichs B,Tepel C, Reinheckel T, Deussing J, Von Figura K, Herzog V, Peters C, Saftig P, Brix K.: Thyroid functions of mouse cathepsins B, K, and L. J. Clin. Invest. 2003; 111: 1733–1745.
25. Buck, M. R., Karustis, D. G., Day, N. A., Honn, K. V. and Sloane, B. F.: Degradation of extracellular-matrix proteins by human cathepsin B from normal and tumour tissues. Biochem J. 1992; 282: 273–278.
26. Ishidoh, K. and Kominami, E.: Procathepsin L degrades extracellular matrix proteins in the presence of glycosaminoglycans in vitro. Biochem. Biophys. Res. Commun. 1995; 217: 624–631.
27. Vasilena Gocheva,Wei Zeng,  Danxia Ke, David Klimstra, Thomas Reinheckel, Christoph Peters, Douglas Hanahan, and Johanna A. Joyce: Distinct roles for cysteine cathepsin genes in multistage tumorigenesis. Genes Dev. 2006; 20: 543–556.
28. Hiroshi Kobayashi, Nobuhiko Moniwa, Motoi Sugimura, Hiromitsu Shinohara, Hidekazu Ohi and Toshhiniko Terao: Effects of membrane-associated cathepsin B on the activation of receptor-bound prourokinase and subsequent invasion of reconstituted basement membranes. Biophys. Acta. 1993; 1178: 55–62.
29. Reiners, J. J. Jr.: Phorbol ester activation of a proteolytic cascade capable of activating latent transforming growth factor-βL a process initiated by the exocytosis of cathepsin B. J. Biol. Chem. 2002; 277: 14829–14837.
30. Behrendt, N.: The urokinase receptor (uPAR) and the uPAR-associated protein (uPARAP/Endo180): membrane proteins engaged in matrix turnover during tissue remodeling. Biol. Chem. 2004; 385: 103–136.
31. Alejandro C. Curino,Lars H. Engelholm, Susan S. Yamada, Kenn Holmbeck, Leif R. Lund, Alfredo A. Molinolo, Niels Behrendt, Boye Schnack Nielsen and Thomas H. Bugge:Intracellular collagen degradation mediated by uPARAP/Endo180 is a major pathway of extracellular matrix turnover during malignancy. J. Cell Biol. 2005; 169: 977–985.
32. Hughes S J, Glover T W, Zhu X X, Kuick R, Thoraval D, Orringer M B, Beer D G, Hanash S: A novel amplicon at 8p22–23 results in overexpression of cathepsin B in esophageal adenocarcinoma. Proc. Natl Acad. Sci. USA 95 1998; 12410–12415.
33. Lin Lin, Sanjeev Aggarwal, ThomasW. Glover Mark Orringer, Samir Hanash and David G. Beer:A minimal critical region of the 8p22–23 amplicon in esophageal adenocarcinomas defined using sequence tagged site-amplification mapping and quantitative polymerase chain reaction includes the GATA-4 gene. Cancer Res. 2000; 60: 1341–1347.

34. Berquin, I. M., Cao, L., Fong, D. and Sloane, B. F.: Identification of two new exons and multiple transcription start points in the 5′-untranslated region of the human cathepsin-B-encoding gene. Gene 1995; 159:143–149.
35. Seth, P., Mahajan, V. S. and Chauhan, S. S.: Transcription of human cathepsin L mRNA species hCATL B from a novel alternative promoter in the first intron of its gene. Gene 2003; 321: 83–91.
36. Arora, S. and Chauhan, S. S.: Identification and characterization of a novel human cathepsin L splice variant. Gene 2002; 293: 123–131.
37. Yan, S. and Sloane, B. F.: Molecular regulation of human cathepsin B: implication in pathologies. Biol. Chem. 2003; 384: 845–854.
38. Gong, Q., Chan, S. J., Bajkowski, A. S., Steiner, D. F. Frankfater, A: Characterization of the cathepsin B gene and multiple mRNAs in human tissues: evidence for alternative splicing of cathepsin B pre-mRNA. DNA Cell Biol. 1993; 12: 299–309.
39. Zwicky, R., Muntener, K., Csucs, G., Goldring, M. B. and Baici, A.: Exploring the role of 5′ alternative splicing and of the 3′-untranslated region of cathepsin B mRNA. Biol. Chem. 2003; 384: 1007–1018.
40. Jean, D., Rousselet, N. and Frade, R.: Expression of cathepsin L in human tumour cells is under the control of distinct regulatory mechanisms. Oncogene 2006; 25: 1474–1784.
41. Paik S, Shak S, Tang G, Kim C, Baker J, Cronin M, Baehner FL, Walker MG, Watson D, Park T, Hiller W, Fisher ER, Wickerham DL, Bryant J, Wolmark N: A multigene assay to predict recurrence of tamoxifen-treated, node-negative breast cancer. N. Engl. J. Med. 2004; 351: 2817–2826.
42. Allinen M, Beroukhim R, Cai L, Brennan C, Lahti-Domenici J, Huang H, Porter D, Hu M, Chin L, Richardson A, Schnitt S, Sellers WR, Polyak K:: Molecular characterization of the tumour microenvironment in breast cancer. Cancer Cell 2004; 6: 17–32.
43. Mikkelsen T, Yan PS, Ho KL, Sameni M, Sloane BF, Rosenblum ML: Immunolocalization of cathepsin B in human glioma: implications for tumor invasion and angiogenesis. J. Neurosurg. 1995; 83:285–290.
44. Cavallo-Medved, D. and Sloane, B. F.: Cell-surface cathepsin B: understanding its functional significance. Curr. Top. Dev. Biol. 2003; 54: 313–341.
45. John Collette, Jeffrey P Bocock , Kyujeong Ahn , Richard L Chapman , Gene Godbold , Susan Yeyeodu and Ann Hart Erickson:Biosynthesis and alternate targeting of the lysosomal cysteine protease cathepsin L. Int. Rev. Cytol. 2004; 241:1–51.
46. Roshy, S., Sloane, B. F. and Moin, K.: Pericellular cathepsin B and malignant progression. Cancer Metastasis Rev. 2003; 22:271–286.
47. Reddy, V. Y., Zhang, Q. Y. and Weiss, S. J.: Pericellular mobilization of the tissue-destructive cysteine proteinases, cathepsins B, L, and S, by human monocyte-derived macrophages. Proc. Natl Acad. Sci. USA 1995; 92: 3849–3853.
48. Punturieri A, Filippov S, Allen E, Caras I, Murray R, Reddy V, Weiss SJ. Regulation of elastinolytic cysteine proteinase activity in normal and cathepsin K-deficient human macrophages. J. Exp. Med. 2000; 192: 789–799.
49. East, L. and Isacke, C. M.: The mannose receptor family. Biochim. Biophys. Acta 2002; 1572: 364–386.
50. Behrendt, N.: The urokinase receptor (uPAR) and the uPAR-associated protein (uPARAP/Endo180): membrane proteins engaged in matrix turnover during tissue remodeling. Biol. Chem. 2004; 385: 103–136.
51. Löser R, Pietzsch J.: Cysteine cathepsins: their role in tumor progression and recent trends in the development of imaging probes. Frontiers in Chemistry. 2015; 3:37.
52. Sameni, M., Dosescu, J., Moin, K. and Sloane, B. F.: Functional imaging of proteolysis: stromal and inflammatory cells increase tumor proteolysis. Mol. Imaging 2003; 2:159–175.
53. Sobotic B,Vizovisek, M, Vidmar R, Van Damme  P, Gocheva V, Joyce JA., Gevaert K, Turk B,  Fonovic, M: Proteomic identification of cysteine cathepsin substrates shed from the surface of cancer cells. Mol. Cell Proteom. 2015; 14:2213–2228.
54. Krueger, S., Haeckel, C., Buehling, F. and Roessner, A.: Inhibitory effects of antisense cathepsin B cDNA transfection on invasion and motility in a human osteosarcoma cell line. Cancer Res. 1999; 59:6010–6014.
55. Sanjeeva Mohanam, Sushma L Jasti, Sudha R Kondraganti, Nirmala Chandrasekar, Sajani S Lakka, Yoshiaki Kin, Gregory N Fuller, Alfred WK Yung, Anthanassios P Kyritsis, Dzung H Dinh, William C Olivero, Meena Gujrati, Francis Ali-Osman and Jasti S Rao.: Down-regulation of cathepsin B expression impairs the invasive and tumorigenic potential of human glioblastoma cells. Oncogene 2001; 20:3665–3673.
56. Sabine Krueger, Udo Kellner, Frank Buehling and Albert Roessner: Cathepsin L antisense oligonucleotides in a human osteosarcoma cell line: effects on the invasive phenotype. Cancer Gene Ther. 2001; 8:522–528.
57. Sabine Krueger, Thomas Kalinski , Tanja Hundertmark , Thomas Wex , Dörthe Küster , Ulrich Peitz , Matthias Ebert , Dorit K Nägler , Udo Kellner , Peter Malfertheiner, Michael Naumann , Christoph Röcken and Albert Roessner: Up-regulation of cathepsin X in Helicobacter pylori gastritis and gastric cancer. J. Pathol. 2005; 207: 32–42.

58. Bonnie F. Sloane, Shiqing Yan,Izabela Podgorski, Bruce E. Linebaugh, Michael L. Cher, Jianxin Mai, Dora Cavallo-Medved, Mansoureh Sameni, Julie Dosescu, Kamiar Moin: Cathepsin B and tumor proteolysis: contribution of the tumor microenvironment. Semin. Cancer Biol. 2005; 15:149–157.
59. Niranjan Yanamandra, Krishna V Gumidyala, Kevin G Waldron, Meena Gujrati, William C Olivero, Dzung H Dinh, Jasti S Raoand Sanjeeva Mohanam: Blockade of cathepsin B expression in human glioblastoma cells is associated with suppression of angiogenesis. Oncogene 2004; 23: 2224–2230.
60. Vasilena Gocheva, Wei Zeng, Danxia Ke, David Klimstra, Thomas Reinheckel, Christoph Peters,Douglas Hanahan and Johanna A. Joyce: Distinct roles for cysteine cathepsin genes in multistage tumorigenesis. Genes Dev. 2006; 20: 543–556.
61. Wang B, Sun J, Kitarmoto s, Yang M, Grubb A, Chapman H.A., Kalluri R, and Shi G.P., Cathepsin S controls angiogenesis and tumor growth via matrix-derived angiogenic factors. J. Biol. Chem. 2005; 281(9): 6020-9.
62. Sevenich L, Bowman RL, Manson SD, Qual DF, Rapaport F, Elie BT, Brogi E, Brastianos PK, Hahn WC, Holsinger LJ, Massague J, Leslie CS, Joyce JA: Analysis of tumour- and stroma-supplied proteolytic networks reveals a brain-metastasis-promoting role for cathepsin S. Nat. Cell Biol. 2014; 16: 876–888.
63. Vasiljeva O, Papazoglou A, Krüger A, Brodoefel H, Korovin M, Deussing J, Augustin N, Nielsen BS, Almholt K, Bogyo M, Peters C, Reinheckel T.: Tumor cell-derived and macrophage-derived cathepsin B promotes progression and lung metastasis of mammary cancer. Cancer Res. 2006; 66: 5242–5250.
64. Sokol, J. P. and Schiemann, W. P.: Cystatin C antagonizes transforming growth factor beta signaling in normal and cancer cells. Mol. Cancer Res. 2004; 2:183–195.
65. Wendong Li, Fang Ding, Liyong Zhang, Zhongmin Liu, Yu Wu, Aiping Luo, Min Wu, Mingrong Wang, Qimin Zhan and Zhihua Liu: Over expression of stefin A in human esophageal squamous cell carcinoma cells inhibits tumor cell growth, angiogenesis, invasion, and metastasis. Clin. Cancer Res. 2005; 11: 8753–8762.
66. Mannello F, Tonti G and Papa S: Matrix metalloproteinase inhibitors as targets of anticancer therapeutics. Curr Cancer Drug Targets 2005; 5: 285–298.VigneswaranN, Wu J, Nagaraj N, James R, Zeeuwen P, Zacharias W: Silencing of cystatin M in metastatic oral cancer cell line MDA-686Ln by siRNA increases cysteine proteinases and legumain activities, cell proliferation and in vitro Life Sci. 2006; 78: 898–907.

67. Mannello F: Natural bio-drugs as matrix metalloproteinase inhibitors: new perspectives on the horizon? Recent Pat Anticancer Drug Discov. 2006; 1: 91–103.
68. Miller KD, Saphner TJ, Waterhouse DM, Chen TT, Rush-Taylor A, Sparano JA, Wolff AC, Cobleigh MA, Galbraith S and Sledge GW: A randomized phase II feasibility trial of BMS-275291 in patients with early stage breast cancer. Clin Cancer Res. 2004; 10: 1971–1975.
69. Sapadin AN and Fleischmajer R: Tetracyclines: nonantibiotic properties and their clinical implications. J Am Acad Dermatol. 2006; 54: 258–265.
70. Gauthier JY, Chauret N, Cromlish W, Desmarais S, Duong LT, Falgueyret JP, Kimmel DB, Lamontagne S, Leger S, LeRiche T, Li CS, Massé F, McKay DJ, Nicoll-Griffith DA, Oballa RM, Palmer JT, Percival MD, Riendeau D, Robichaud J, Rodan GA, Rodan SB, Seto C, ThérienM, Truong VL, Venuti MC, Wesolowski G, Young RN, Zamboni R, Black WC: The discovery of odanacatib (MK-0822), a selective inhibitor of cathepsin K. Bioorg. Med. Chem. Lett 2008; 18(3): 923–8.
71. AsagiriM, Hirai T, Kunigami T, Kamano S, Gober HJ, Okamoto K, Nishikawa K, Latz E, Golenbock DT, Aoki K, Ohya K, Imai Y, Morishita Y, Miyazono K, Kato S, Saftig P, Takayanagi H Cathepsin K-dependent toll-like receptor 9 signaling revealed in experimental arthritis. Science. 2008; 319(5863): 624-627.
72. Ronit Satchi-Fainaro, Mark Puder, John W Davies, Hai T Tran, David A Sampson, Arin K Greene, Gabriel Corfas and Judah Folkman: Targeting angiogenesis witha conjugate of HPMA copolymer and TNP-470. Nature Med. 2004; 10: 255–261.
73. Rekha G. Panchal, Evelyn Cusack, Stephen Cheley and  Hagan Bayley: Tumor protease-activated, pore-forming toxins from a combinatorial library. Nature Biotechnol. 1996; 14: 852–856.
74. Potrich C, Tomazzolli R, Dalla SerraM, Anderluh G, Malovrh P, Macek P, Menestrina G, Tejuca M: Cytotoxic activity of a tumor protease-activated pore-forming toxin. Bioconjug. Chem. 2005; 16: 369–376.
75. Bien S, Ritter CA, Kranz M, Scharf C, Steil L, Hummel M, Völker U, Cascorbi I, Kroemer HK: Influence of doxorubicin on gene expression and protein pattern in HeLa cells. Int. J. Clin. Pharmacol. Ther. 2004; 42: 640-641.
    

    ---

    How to cite this article:

    Patil S and Saraswathy N: Enzymes as targets for cancer therapy. Int J Pharm Sci Res 2017; 8(11): 4525-32.doi: 10.13040/IJPSR.0975-8232.8(11).4525-32.

    ---

    All © 2013 are reserved by International Journal of Pharmaceutical Sciences and Research. This Journal licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.

    ---