The Role Of Cathepsin Biology Essay

The biological environment in which malignant neoplastic disease arises plays a critical function in suppressing tumour development ; conversely it can besides be manipulated by cancerous cells into supplying factors that support tumor patterned advance. In recent old ages, there has been heightened involvement in the functional function of the microenvironment and modulators of this tumour niche on tumorigenesis, distant metastasis and drug opposition. The interaction, inhibitory and stimulatory ordinance of assorted tumour bed associated elements, with increased focal point on the specific functions of proteolytic enzymes, malignant neoplastic disease associated fibroblast ( CAF ) , tumour associated macrophage ( TAM ) , and para-tumor cytokines, have besides received attending. Our long-run aim is to understand the molecular XT between tumour and the stromal cells, and to find the mechanisms by which host tissues are co-opted to ease malignant neoplastic disease patterned advance.

Cathepsin S ( Cat S ) , a cysteine peptidase with documented endoproteolytic activity and wide pH profile, is up-regulated in many human and murine malignant neoplastic diseases and its increased look is associated with malignant patterned advance and hapless patient forecast. Despite the accentuated involvement and increasing volume of work sing the mechanism of Cat S-induced loss of tissue architectural form or devastation, and malignant neoplastic disease patterned advance, the specific molecular mechanisms by which they facilitate tumour aggressiveness and mediate stemness are still inadequately defined. In this survey, attending is drawn to a cysteine peptidase, secreted about entirely by endotheliocytes and antigen presenting cells, particularly macrophages, which has an immunosuppressive consequence and problematic anti-apoptotic activities in assorted cell types, including TAM and transformed cells.

This proposal focuses on the part of the Cat S to tumor-host molecular interactions, tumour ‘malignantization ‘ and its putative function as a marker of malignant neoplastic disease stemness. Our hypothesis is that Cat S is important for distinguishable stairss in geting each distinguishable ‘hallmark capableness ‘ of malignant neoplastic disease, and phenotypic features of malignant neoplastic disease root cell in colorectal carcinoma ( CRC ) . We will look into by what signalling pathway Cat S modulates tumor patterned advance. We will prove the hypothesis that Cat S non merely promotes tumor invasion by a molecular mechanism necessitating the extracellular cleavage of E-cadherin, and facilitate angiogenesis through the debasement and release of vascular cellar membrane proteins, but besides that Cat S is a marker of stemness in CRC. We will besides find if the cellular beginnings and substrates of Cat S in the neoplastic microenvironment are necessary for its pro-tumorigenic maps and clonigenicity. To accomplish these purposes, we will analyse Cat S with a combination of our lab-designed novel cell co-culture system, biochemical and pharmacological experiments.

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These surveies will supply critical penetrations into the biological science of Cat S in malignant neoplastic disease, the function of the microenvironment in tumour patterned advance, and enable the development and application of curative malignant neoplastic disease schemes based on surveies in this pre-clinical co-culture system theoretical account.


Cathepsin, Cathepsin S, Proteases, Cysteine proteinases, Proteolytic enzymes, Cancer root cells, Tumor originating cells, Stemness, Tumor associated macrophages, Microenvironment, Macrophage, Colon, CRC, Malignant, Tumor, Invasion

Project Generic Title:

A Prospective Survey of Proteolytic Factors as Surrogate Markers in Human Malignant Diseases

Undertaking Title ( 1 ) :

The Role of Cathepsin S in Malignant Colon Carcinoma Progression, Stemness and its Regulation Mechanism

Problem Definition:

In recent old ages, globally and more peculiarly in resource-limited communities, malignances are going a common diagnosing with great economic, emotional and physical effect. This is likely non because it is a fresh wellness status occupying the universe but instead due to increased consciousness, better diagnostic efforts and improved backing of institutionalised Orthodox medical installations. However, it is unfortunate that many turn to orthodox medical specialty at advanced or end phase, owing mostly to unavailability to available installations and/or high cost of Orthodox medical assistance in these resource-limited communities.

The World Health Organization 2008 mortality factsheet shows that approximately 70 % of all malignant neoplastic disease related deceases occurred in low- and middle-income states, and undertakings that malignant neoplastic disease deceases worldwide would go on to lift to over 13.1 million in 2030. ( 1 ) Therefore, this underscores the magnitude of the malignant neoplastic disease load, and the demand for more matter-of-fact attack to unknoting an advanced, cheap, readily available and accessible malignant neoplastic disease testing tool in these hapless communities.

Undertaking Background:

Colorectal malignant neoplastic disease ( CRC ) , a mostly preventable disease, presents an tremendous socio-economic and clinical challenge, being the 2nd ( 2nd ) most prevailing malignant morbidity amongst females, 3rd ( 3rd ) , amongst males and the 4th ( 4th ) major cause of mortality worldwide. Most recent published figures from WHO showed that planetary malignant neoplastic disease mortality was 7.6 million with CRC accounting for approximately 8.5 % of this mortality – a unreassuring 647 121 deceases ( 2 ) , and an one-year incidence of over one million freshly diagnosed instances with about no discriminatory gender favoritism.

Colorectal malignant neoplastic disease, like many other human malignances, is non mono-etiological in pathogenesis ; it is instead a merchandise of a combination of assorted familial, epigenetic, bodily, environmental and endogenous factors. CRC is an epithelial-cell-derived GI malignance get downing with benign adenomatous precursors ( polyps ) and is best appreciated in visible radiation of the conventional adenoma-carcinoma sequence. Characterized by dazedly progressive dysplastic epithelial giantism, impaired distinction reflected as an enlargement of nascent cells with matching depletion of mature cells, and increasing invasive cell venue, CRC is a multi-seriate pathology fuelled by aberrances that serially enhance malignant traits.

It is pertinent at this occasion to province that the writer does non see CRC to be a simplistic monoclonal or homogeneous assembly of mutant cells. Pulling from tremendous organic structure of grounds, we view colorectal carcinoma, like most other types of human malignances, to be a composite tissue system characterized by deregulated entropic growing, modulated by a little intra-tumor fold of mutant malignant cells with an built-in capacity for self-renewal, and care of post-differentiation phenotypic heterogeneousness, every bit good as, an acquired aggressive and hyper-proliferative leaning. The writer addresses this later.

The passage from normal epithelial tissue to benign adenomatous polyps and later to the malignant phase takes one to three decennaries, accompanied by a overplus of epigenetic and familial changes and is frequently accelerated in the confines of a permissive tumour bed. By tumour bed, we refer to the neoplastic microenvironment made up of the transformed cells and their surrounding back uping surroundings. The support construction is a dramatis personae of normal non-cancerous matrix stroma cells ( epithelial cells, fibroblasts, adipocytes ) , vascular elements ( endothelial cells, pericytes ) , immune and inflammatory constituents ( T-lymphocytes, B-lymphocytes, natural slayer and dendritic cells, mast cells, monocytes / macrophages ) , every bit good as the legion associated chemokines and cytokines.

Communication between the colonic tumour cells and their microenvironment helps drive the procedure of tumour growing and development. Tumor patterned advance is dependent on what happens around the tumour cells, every bit much as what takes topographic point within them, therefore, tissue architecture with a malignant phenotype is necessary for colonic tumour cell endurance and care. Enhanced angiogenic activity and increased invasiveness – two ( 2 ) key trademarks of tumour patterned advance, are really microenvironment-dependent. Tumor masses produce substances capable of pulling a changeless inflow of pro – and anti-inflammatory cells. These cells one time in the tumour bed or microenvironment as it is conventionally called, are polarized towards an alternate stimulation and get down to heighten cellular proliferation, stroma remodelling and tumour patterned advance. ( 3, 4, 5 ) Though controversial, many surveies show that CRC sensitivity is positively regulated by the infiltration and colonisation of the tumour bed by immune cells, particularly, macrophages. ( 3 )

The immune-inflammatory constituent of the tumour bed, peculiarly the so called tumour associated macrophages ( TAMs ) , plays no little function in the elaboration of tumor-susceptibility. Despite general cognition that the immune system plays a critical function in the designation and subsequent riddance of transformed cells, a map termed ‘cancer immunosurveillance ‘ , it is nevertheless, non all perpetrators that are prosecuted, as some tumour cells frequently escape the immunosurveillance machinery. Having evaded acknowledgment and riddance by the activated Natural slayers ( NKs ) and other T lymph cells, these tumour cells now have their growing facilitated by the one time ‘hostile ‘ immune system. How? Via the TAM mediated neovascularisation tract. ( 6, 7 )

As first line of defense mechanism in most neoplastic terrain, macrophages, due to their characteristic capacity for rapid infiltration and colonisation of lesion sites, in add-on to their ability to bring forth cytokines which attract and activate NKs and dendritic cells ( DCs ) , are considered really of import in tumour pathogenesis and development ; ( 8 ) howbeit, the ‘law enforcement agent ‘ frequently clip may turn out as an ‘accomplice ‘ .

Contrary to the by and large accepted anti-pathogenic or pathogenocidal function of macrophages, increasing grounds reveal that TAMs under the changing transition of several enzymes, cytokines and chemokines, possess a M1 & lt ; M2 ( M1/M2 & lt ; 1 ) polarisation ratio and as such display an immunosuppressive, pro-angiogenesis and pro-neoplastic leaning.

This self-contradictory function of TAM in tumour development is progressively being supported by grounds from assorted plants. Alberto Mantovani, finely showed in his work on TAM ‘s function in patterned advance of tumor, how a friendly macrophage ( M1 phenotype ) set uping tumour rejection could besides move as enemy ( M2 phenotype ) advancing tumour proliferation, angiogenesis and metastasis ( 9 ) , speculating that this pluriphenotypic and multifunctional nature of TAM relies on the province of its microenvironment, since their activation and map is modulated by local stimulations. ( 10 )

Macrophage enlisting and migration to tumor mass is mediated by chemokine ( C-C motive ) ligand 2 ( CCL2 ) besides known as monocyte chemotactic protein-1 ( MCP-1 ) and chemokine ( C-C motive ) ligand 5 ( CCL5 ) known besides as RANTES ( regulated and normal T cell expressed and secreted ) . The measure of macrophage recruited is independent of CCL2, yet, macrophage-associated angiogenesis is extremely dependent on it. Aside CCL2 and RANTES, other chemokines such as CCL3, CCL4, CCL8, CXCL8, CCL22 and CCL18 have been implicated in tumour mass colonisation by TAM, nevertheless, the precise extent of their engagement needs more elucidation. ( 11 – 16 )

The function of cytokines on TAM activity can non be overstated. Colony exciting factor 1 ( CSF-1 ) , which is produced by monocytes, macrophages and a figure of other cells, stimulates the enlisting, proliferation, distinction and endurance of monocytes/macrophages in the tumour mass. Elevated degree of CSF 1 activates and upregulates the tumour bed macrophage content ; these in bend positively modulate angiogenesis via VEGF mediation and therefore enhances tumour proliferation. Vasculo-endothelial growing factor ( VEGF ) have been shown to trip go arounding myeloid cells homing in grownup neovascularisation sites and they sustain the endurance of recruited paravascular cells via CXCL12 stroma cell derived factor-1 look.

Of great relevancy in the malignant neoplastic disease biological science is the function of proteolytic enzymes, and more specifically, the cysteine proteases. ( 17 – 23 ) Based on available groundss from significant organic structure of literature, this group of peptidases are facilitators of several stairss in malignant neoplastic disease patterned advance. Several cysteine peptidases have been implicated in tumour growing, tumour cell invasion, metastasis, and more late, in tumor-related angiogenesis, therefore, of no less significance in tumour induction, patterned advance, and putative stemness acquisition, is the function played by the well-known cysteine peptidase with an germinating structural, functional and regulative word picture, Cathepsin S ( Cat S ) . ( 17, 18 )

Cat S, a potent elastin and collagen degrading enzyme, with a restricted or tissue-specific look form and about 30 kDa molecular mass, ( 17, 24 ) belong to the cysteine proteinases household ( CA1 ) of the Papain ace household, comprising of other peptidases such as cathepsins B, L, C and H. ( 25 ) In add-on to its noteworthy spacial association with antigen processing, and peptide presentation in immunocytes, particularly the professional antigen-presenting cells ( APCs ) and its function in bio-reparative procedures such as lesion healing and bone remodelling, ( 26 ) the plausible work of Guo-Ping Shi et al. , on the word picture of Cat S in 1994, and the 1995 Vivek Reddy et Al. presentation of the pericellular mobilisation of Cat S by human monocyte-derived macrophages ( hMDM ) , an immunocyte, and a non-redundant component of the tumour niche, aroused involvement in their function in tumour development, ensuing in mounting grounds implicating Cat S in tumour induction and patterned advance via its mitogenic, anti-apoptotic, pro-invasion, pro-epithelial-mesenchymal transmutation, powerful angiogenic and pro-osteogenesis activities. ( 17, 25, 26, 27 )

Predominantly expressed in certain cellular constituents of the tumour microenvironment, Cat S is upregulated in several presymptomatic theoretical accounts of assorted malignances, with a positive correlativity between their grade of look, and/or, secernment, and increased tumour cell aggressiveness semen ‘malignantization ‘ . ( 28 )

In add-on to its restricted tissue distribution, by exhibiting a important part of its proteolytic activity at impersonal pH, Cat S differs from other cysteine cathepsin isoforms in its leaning for secernment and extracellular bioactivity. ( 29 ) Cat S is an effectual go-between of the irreversible posttranslational alteration of protein via the contact action of the amide bond hydrolysis. The care of its proteolytic and associated properties even after long incubation at impersonal pH, undertakings the discriminatory suitableness of Cat S as powerful effecter of tissue disintegration and extracellular matrix ( ECM ) loss of architectural form in the non-acidic extracellular niche. ( 30 ) This ECM loss of structural unity or remodelling, and by illation, epithelial mesenchymal passage ( EMT ) is characteristic of the histopathologically defined CRC adenoma-carcinoma tumour patterned advance sequence and metastasis. Metastasis is the procedure by which tumour cells get an aggressive phenotype. It is a multiseriate procedure affecting the loss of cell-cell and cell-host bond, withdrawal of malignant cells and their invasion of the para-tumor tissues. Increasing grounds reveals that tumor metastasis and non the primary tumour is the chief cause of the surging mortality among CRC patients. In fact, depending on the tumour phase, an estimated 20 % to 70 % and 10 % to 20 % of CRC-related deceases are secondary to intrahepatic and intrapulmonary metastasis severally. ( 31 ) The high incidence of these metastatic instances and tumour return contribute to CRC ranking as one of the most frequent human malignant neoplastic disease with a forecast that remains hapless.

In several malignant neoplastic disease types, Cat S is translocated from its usual intracellular lysosomal home ground into the extracellular surroundings, where it is believed to advance ECM remodelling and finally, tumour invasion and patterned advance in the tumour niche. ( 32 ) Therefore, implicated as a perpetrator in matrix debasement, and by extension in the EMT and metastatic procedure, we will measure Cat S activity and look in CRC against fluctuations in epithelial and mesenchymal markers. Upregulation of mesenchymal markers such as N-cadherin, fibronectin, laminin, beta-tubulin, and vimentin, in contrast with, downregulation of epithelial markers such as cytokeratin, E-cadherin and beta-catenin, are specifying properties of EMT. E-cadherin has been shown to be a substrate of Cat S. The loss of E-cadherin, a cardinal constituent of the adherens junction, every bit good as a go-between of cell-cell adhesion and epithelial organisation, facilitates the adenoma – carcinoma sequence and therefore enhances tumour aggressiveness. ( 33, 34 )

Beyond its anti-apoptotic activity, ( 34 ) the endogenous look of Cat S by endothelial cells and tumor associated macrophages is speculated to quickly increased in response to nascent and sustained inflammatory stimulations. In certain malignant neoplastic disease types, such as CRC, where chronic redness precedes and enhances tumour formation, and many others, where inflammatory signal transduction is triggered by intrinsic tumour cell and tumour host/ microenvironment interaction, it is speculated that the upregulation of Cat S look in the tumour microenvironment may be declarative of Mantovani ‘s tumor-promoting ‘smouldering redness ‘ , which enhances non merely macrophage endurance, but the endurance, proliferation, angiogenesis, increased invasiveness and migratory capableness of malignant cells, while overthrowing adaptative unsusceptibility and changing tumour response to endocrines and chemotherapy. ( 35 )

In recent old ages, turning grounds show that local and distant airing of malignant cells, every bit good as malignant neoplastic disease return, is linked to the activities of a phenotypic little subpopulation of tumour cells believed to possess tumor-growth initiating abilities ; ( reviewed in 36 ) and our background cognition of the deduction of Cat S in epithelial disorganisation plus enhanced tumour cell aggressiveness ; We hypothesize that Cat S may non be an guiltless bystander in the malignant neoplastic disease stemness sphere. We speculate that Cat S is an active and non-redundant participant in the induction and/or care of this phenotypic subset of tumour cells, functionally referred to as malignant neoplastic disease root cells ( CSCs ) , or more sooner, tumour originating cells ( TICs ) . This subset of malignant cells is attributed with the capableness to bring forth tumour cells ( tumorigenicity ) which non merely keep a differentiated phenotype, but besides reproduce a complete phenotypic and structural heterogeneousness of the parental mutations ( clonogenicity ) . ( 37 ) This survey will therefore include an rating of the possible engagement of Cat S in the care of these malignant neoplastic disease stem-like ‘side-population ‘ ( SP ) cells in CRC cell lines, and their bad function in opposition to conventional chemotherapy and radiation therapy. Validation of our hypothesis on the engagement of Cat S in acquisition and/or care of tumour stemness would bespeak the possible clinical serviceability of Cat S, non merely as an effectual predictive tool, but besides as a powerful armory in get the better ofing chemoresistance secondary to the activities of the alleged malignant neoplastic disease root cells.

Despite increased volume of work associating to cysteine cathepsins and malignant neoplastic disease biological science, yet, the molecular mechanism underlying Cat S secernment and over-expression has non been to the full elucidated, nor has the intrinsic relationship between the cysteine cathepsin look and tumour patterned advance, every bit good as stemness.

We project that by researching, qualifying and cataloguing the distinguishable function of Cat S in malignant neoplastic disease development and stemness, we would be adding to the organic structure of cognition by which the long-run end of set uping a malignant neoplastic disease testing tool that could be molecularly targeted, as an effectual oncoprophylaxis and anticancer curative scheme.

This survey seeks to derive penetration into the function of Cat S in the induction and patterned advance of malignances, particularly colorectal malignant neoplastic disease, look into the association of Cat S and tumour stemness, and effort to proffer an efficient curative scheme. The aim of this proposal is to clear up the molecular mechanism underlying Cat S- tumour advancing function. At this phase, this undertaking will concentrate on the usage of human colorectal malignant neoplastic disease cell lines.

Illustrations & A ; Charts:

( 38 )

( 38 )

( 39 )

In this undertaking, the specific aims are as follows:

Research Objectives & A ; Hypothesiss


To look into the endogenous look of Cat S in colorectal carcinoma ellipsoid of revolution cells

To measure the correlativity between Cat S look and tumour stage/progression

To look into the consequence of Cat S suppression on tumour originating cell activities

To formalize the potencies of Cat S as curative mark in chemoresistant CRC






Experimental Design:

A mated panel ( parental and spheroid ) of selected colorectal malignant neoplastic disease cell lines with changing grade of aggressiveness will be generated in conformity with our lab standardized protocol. Validation of the spheroid cells as CRC root cells will be done utilizing anti-EpCAM and anti-CD 44 antibodies. ( 40 ) Using the western blot/ immunoblotting check, endogenous look position of Cat S in the cells lines will be investigated and a comparative analysis of look degrees in matching brace done. Quantitative PCR ( q-PCR ) will be employed to measure correlativity between Cat S courier and protein degree. Our sister lab- generated cell co-culture system theoretical account will be used to prove the hypotheses and ascertain to what extent M2 and/or M1 macrophages and the programmed cell death inhibitor of macrophages ( AIM ) negatively modulate Cat S look. The function of Cat S in tumour patterned advance would be later validated utilizing the matrigel invasion, and wound mending checks. HUVEC angiogenesis check would besides be done to analyze angiogenic effects of Cat S activation and silencing. In vivo activities would be evaluated utilizing extremely malignant colon cell lines and CRC root cell lines xenograft surveies.

Materials and Methods

Choice and civilization of CRC cell lines

DLD-1, SW480, SW620, HCT-116, and HT 29 colorectal cell lines will be chosen for this survey

SP analysis and purification utilizing flow-cytometry

Culture of SP cells into tumour ellipsoid of revolution cells

Colony formation of SP and non-SP cells

Wound mending check to measure if and how EMT in lesion healing occurs under addition and loss of Cat S maps

Matrigel Invasion assay to measure the migration ability of the cell lines under addition and loss of Cat S maps

Western Blotting to corroborate Cathepsin S look in the panel of cell lines

Rearward RNA polymerase ( RT ) – and Real clip ( Q ) -PCR

Co-culture of Cat S showing CRC cell lines with THP-1 cell line

Data digest and statistical analysis

What this Survey will add to the field?

At the terminal of this survey, we look to demystify the presently ill-defined molecular mechanism underlying Cat S activities, its regulative function in the tumour microenvironment and how it enhances tumour patterned advance.

To the best of our cognition, this is the first survey with purpose to measure Cat S ability to bring on and/or maintain tumour stemness. No old survey has shown the relationship between Cat S look and alleged malignant neoplastic disease root cell activities.

Validating our hypothesis that Cat S activity promotes malignant neoplastic disease cell stemness would be a milepost in our journey towards fading of tumour aggressiveness and riddance of CSC-related chemo- and radio-therapy.


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