TUMOR CELLS CAUGHT IN THE ACT OF INVADING: THEIR STRATEGY FOR ENHANCED CELL MOTILITY

BY: WEIGANG WANG, SUMANTA GOSWAMI, ERIK SAHAI, JEFFREY B WYCKOFF, JEFFREY E. SEGALL AND JOHN S. CONDEELIS

Presented By: Lana Awad and Sebastian Lukjan

Motivation of research, why they did what they did… Understand steps that

cancer cells take to spread. Want to relate gene

expression pattern with likelihood of metastasis- diagnostics

Ultimate goal is to find strategies to slow spread of tumor cells - therapeutics

Current methods to study cancer metastasis had limitations

http://en.wikipedia.org/wiki/File:Secondary_tumor_deposits_in_the_liver_from_a_primary_cancer_of_the_pancreas.jpg#file

Analysis of Primary whole tumor

Problem: average expression patterns in all diverse tumor cells and isn’t indicative of invading cells.

Wang et al

Analysis of cells isolated from fixed tumorProblem: metastatic cells are identified by

morphological characteristics in fixed tissue

Wang et al

Analysis of metastases tumorProblem: Needs to be cell cultured and In vitro

conditions may affect gene conditions differently than in vivo conditions

Wang et al

Our Method, catching tumor cells red handed ….. while they are invading

using chemotaxis

Chemotaxis toward blood vessels enhances metastasis

Growth Factor concentration gradient directs invasive cells to blood vessels

Tumor cells express more EGF receptors and respond to this gradient better

Their Method:In vivo Invasion Assay Used chemotaxis

Chemotaxis to blood

vessels enhances metastasis Used a microneedle with

known chemo attractants for metastasis Then used microarrays to study gene

experssion patternsIn particular looked for change in gene regulation

with genes that affected motility

Paracrine Chemotaxis Carcinoma cells

(CC) produce CSF-1 to drive Tumor Associated Macrophages (TAM) to blood vessel

TAM procedures EGF to direct CC towards the blood vessel

Wang et al

Gene Expression Trends

mRNA levels for genes related to mobility affected

mRNA levels for genes related to cell polarity affected

A key Discrepancy in Cancer Models Gene expression results indicate the

possibility that metastasis can occur in early tumors

Lead to the questioning of current model of cancer

Hypothesis: Tumor Microenvironment Invasion Model

Wang et al

Key Hypothesis Facets

Novel :Transient gene expression changesMetastasis can occur at earlier or later timesMicroenvironments play a direct role in cell

invasion Hypothesis still needs to be tested

In situ hybridization

Significance to Cancer research

Potential therapeutic agents to prevent metastasis characterize behavior of metastatic tumors

on the cellular level.Utilize this understanding to create better

therapeutic agents

The End