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Cancer cell Migration during Invasion and

Metastasis

By Lokesh Patil

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Overview of cancer spreading stages

Primary tumor formation Local Invasion Intravasation

Transport and survival in through

circulation

Arrest at distant organ siteExtravasation

Micrometastasis formation

Metastatic colonization

Clinically detectable metastases

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Invasion-Metastasis cascade

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Tumor formation

• Because of failure in DNA replication of cells causing uncontrolled division

• Occurs at molecular level in the cell nucleus

• Cellullar instability->daughter cells interacting with environment

• At cellular level->dynamics have longer space scale and slower time scale that molecular level.

e.g, enzymatic degradation in ms whereas cell replication about a day Fig 1 : Comparison of normal and

Cancer cell division

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Local InvasionMMP(Matrix

Metalloproteinase) driven proteolysis causes loss of

BM barrier

Invasion of cancer cells into stromal compartment

Stroma becomes increasingly reactive

These Stromal cells enhance the aggressiveness

of cancer cells

Fig 2: Local Invasion(marked in circle)

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Intravasation• Entry of cancer cells into the lumina of blood vessel

or lymphatic vessel • Hematogenous circulation is the major mechanism for cancer cell dispersion• Facilitated by molecular changes • Strongly influenced by structural characteristics of tumor-associated blood vessels• Weak blood vessel-endothelial cells interactions promote intravasation Fig 3 : Tumor cell crossing the endothelial

cell barrier

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CTC(Circulating tumor cells) survival

• CTCs are anchorage dependent cells• CTCs(20-30um)• Luminal Dia. of capillaries(~8um)• Therefore CTCs spend short amount of time through circulation hence avoiding anoikis• CTCs also need to avoid hemodymic shear forces and predation by immune cells. They form emboli with platelets to avoid this.• Important clinical relevance

Fig 4: CTC pathway

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CTC arrest and Extravasation

• Still unknown whether specificity for sites is caused by vessel size restrictions or predetermined predilections

Tumor Metastasis: Molecular Insights and Evolving Paradigms Valastyan, Scott; Weinberg, Robert�A. Cell

doi:10.1016/j.cell.2011.09.024 (volume 147 issue 2 pp.275 - 292)

Fig 5: Metastasis tropism: Carcinomas originating from a particular epithelial tissue form detectablemetastases in only a limited subset of theoretically possible distant organ sites. Shown here are the most common sites of metastasis for six well-studied carcinoma types. Primary tumors are depicted in red. Thickness of black linesreflects the relative frequencies with which a given primary tumor type metastasizes to the indicated distant organ site.

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CTC arrest and ExtravasationSteps of Extravasation: 1) Transient Adhesion of TC(tumor cell) to EC(Endothelial cell)-involves endothelial adhesion molecules E and P selectins. This step is associated with rolling

2) This step causes even more firm adhesion

3) The TC slips through endothelial cell-cell junction

Fig 6: Simplistic mechanism of Extravasation

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In-vitro Extravasation model- Factors affecting TC transmigration

-48 well “flow migration” Boyden chamber used

Variables that are quantified:-PMN tethering freq is determined(which is normalized against cell flux on surface)-Total no. of tethered PMNs(polymorphonuclear neutrophils)-No. of collisions b/w TCs and tethered PMNs-Aggregation of TCs with tethered PMNs as a result of collisions-Final attachment of aggregates with EC

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Effect of PMN, ICAM-1 and E-selectin on cell migration

Fig 7 : All cases are at flow shear stress of 0.4 dyn/cm2 C8161, WM9, WM35 are type of cancer cells from cell lines ICAM 1- Intercellular adhesion molecule (a) Effect of addition of PMN to TC cell supension (b) Effect of blocking I-CAM1 and E-selectinDong, C., 2011. Adhesion and Signaling of Tumor Cells to Leukocytes and Endothelium in Cancer Metastasis Studies in Mechanobiology, Tissue Engineering and Biomaterials 4: 477-521

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Effect of fluid shear on tumor cell(TC) migration

• Either shear rate(ý) or shear stress (τ=μý) was kept constant, while other one varied by changing μ.

Dong, C., 2011. Adhesion and Signaling of Tumor Cells to Leukocytes and Endothelium in Cancer Metastasis Studies in Mechanobiology, Tissue Engineering and Biomaterials 4: 477-521

Fig 8 : (a)TC migration varies under constant shear stress but increasing shear rate [(b), (c)]migration does not change for changes in shear stress data

Conclusion:-PMN facilitated migration is affected by shear rate and not by shear stress

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Receptor-ligand mechanics

-kon governs the likelyhood of receptor to form bond with ligand on other cell

AL - available surface area for receptor on ligand bearing cellnL - no. of ligands of cellnB - no. of bonds already formedЄ – distance b/w two cellsk⁰on – Association rate for receptor-ligand binding under zero- force conditionσts – bond spring constantλ - equilibrium length

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Mathematical model for tissue invasion

Hybrid discrete-continuum model for tissue invasion

Assumptions-Invasion triggered by peripheral cancer cell-ECM

contact- Amount of molecules interacting is large enough - Cells are considered discrete particles About the model• Two scale approach-Intracellular environment

affects the extracellular environment• Continuum part of model describes chemical-ECM

interactions• The discrete part models the individual cells

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Chemical-ECM environmentCancer cells in contact

with the protein network release MMPs

ECM is modified by degradation[Fig 9 ]

Change in adjacent stroma configuration

Protein network-cell interaction causing mitosis

via GF absorbtion in degraded ECM

Stimulates cells to migrate via chemotaxis and haptotaxis

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Chemical-ECM environmentEquations governing enzymes’ interactions with

adjacent stroma

2- Diffusion of enzymes in surrounding environment

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E(x,t) – Conc. Of MMPs/uPAs(Urokinase plasminogen actovator)

M(x,t)- Density of ECM

A(x,t) – Density of degraded ECM, in which cells can absorb GFsBє(x) - ball of radius є , centered at xi

1 - Instantaneous local enzyme production

Where N(x, t) is the no. of cellsat time t in surrounding neighbourhoodsuch that

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Chemical-ECM environment

Fig 9 : Change in ECM density as it is degraded by a single cell placed on a petri dish

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Chemical-ECM environment

Fig 10 : Plot of concentration profile overtime of chemoattractants and GFs as they are released from the ECM

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Cell modelling

Cells are assumed as free interacting particles in 2d space

• Two cells interact with each other according to a potential energy function(represents cell-cell adhesion)

• Potential energy of cell-cell bond at time t is given as

• h->capacity to bond

Ignacio Ramis-Conde, Mark A.J. Chaplain, Alexander R.A. Anderson, Mathematical modelling of cancer cell invasion of tissue, Mathematical and Computer Modelling, Volume 47, Issues 5-6, March 2008, Pages 533-545, ISSN 0895-7177, 10.1016/j.mcm.2007.02.034.

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Intercellular Adhesion as a Potential function

Fig 11 : (Left)Interaction energy between two cells separated by a distance x(scaled relative to radius of avg cancer cell. (Right) Interaction energy between two cells in a 2D domain

Ignacio Ramis-Conde, Mark A.J. Chaplain, Alexander R.A. Anderson, Mathematical modelling of cancer cell invasion of tissue, Mathematical and Computer Modelling, Volume 47, Issues 5-6, March 2008, Pages 533-545, ISSN 0895-7177, 10.1016/j.mcm.2007.02.034.

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Modelling cell movement

-Cells movement is governed by potential function

-In absence of any interaction with ECM motion is decided solely by

- Cells are assumed to move at constant speed

- In case of cell-ECM interactions, cell movement is also affected by chemoattractant gradients

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Cell mitosis

• Two causes-Autocrine stimulus and cell-GF interaction

R(xi , t) – Probability function for mitosis rateP0 – Mitosis rate caused solely by autocrine stimulus

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Tumor growth

Fig 12:Evolution of cancer cells as they invade the ECM

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References[1] Tumor Metastasis: Molecular Insights and Evolving Paradigms Valastyan, Scott; Weinberg, Robert A. Cell doi:10.1016/j.cell.2011.09.024 �[2] http://www.oncoursesystems.com/school/webpage.aspx?id=10845583&xpage=789375[3] http://theoncologist.alphamedpress.org/content/14/11/1070/F1.expansion[4] http://www.springerimages.com/Images/Biomedicine/1-10.1007_s12307-008-0007-2-4[5] Dong, C., 2011. Adhesion and Signaling of Tumor Cells to Leukocytes and Endothelium in Cancer

Metastasis Studies in Mechanobiology, Tissue Engineering and Biomaterials 4: 477-521[6] Ignacio Ramis-Conde, Mark A.J. Chaplain, Alexander R.A. Anderson, Mathematical modelling of cancer cell

invasion of tissue, Mathematical and Computer Modelling, Volume 47, Issues 5-6, March 2008, Pages 533-545, ISSN 0895-7177, 10.1016/j.mcm.2007.02.034.

[7] Subra Suresh, Biomechanics and biophysics of cancer cells, Acta Biomaterialia, Volume 3, Issue 4, July 2007, Pages 413-438, ISSN 1742-7061, 10.1016/j.actbio.2007.04.002.

[8] Yangjin Kim, Magdalena A. Stolarska, Hans G. Othmer, The role of the microenvironment in tumor growth and invasion, Progress in Biophysics and Molecular Biology, Volume 106, Issue 2, August 2011, Pages 353-379, ISSN 0079-6107, 10.1016/j.pbiomolbio.2011.06.006.

[9] Simone Spaderna, Otto Schmalhofer, Falk Hlubek, Geert Berx, Andreas Eger, Susanne Merkel, Andreas Jung, Thomas Kirchner, Thomas Brabletz, A Transient, EMT-Linked Loss of Basement Membranes Indicates Metastasis and Poor Survival in Colorectal Cancer, Gastroenterology, Volume 131, Issue 3, September 2006, Pages 830-840, ISSN 0016-5085, 10.1053/j.gastro.2006.06.016.

[10] Brian Elenbaas, Robert A. Weinberg, Heterotypic Signaling between Epithelial Tumor Cells and Fibroblasts in Carcinoma Formation, Experimental Cell Research, Volume 264, Issue 1, 10 March 2001, Pages 169-184, ISSN 0014-4827, 10.1006/excr.2000.5133.

[11] N. BELLOMO. ON THE FOUNDATIONS OF CANCER MODELLING: SELECTED TOPICS, SPECULATIONS, AND PERSPECTIVES. Mathematical Models and Methods in Applied Sciences Vol. 18, No. 4 (2008) 593–646°c World Scientific Publishing Company

[12] http://topnews.us/content/221000-pancreatic-cancer-and-circulating-tumor-cells-linked-each-other

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