Invasiveness vs. Metastasis in Cancer

Invasiveness refers to the ability of cancer cells to penetrate surrounding tissues, while metastasis involves the spread of cancer cells from the primary tumor site to distant organs or tissues, forming secondary tumors.

The key components include adhesion molecules like integrins and cadherins, the extracellular matrix (ECM), the actin cytoskeleton, and signaling molecules like Rho GTPases.

Integrins mediate cell-matrix interactions, anchoring cells to the ECM and enabling migration. Cadherins maintain cell-cell adhesions, contributing to tissue integrity and coordinated movement.

<p>Tumor cells often exhibit altered integrin profiles, enhancing motility and survival. Loss of E-cadherin, a type of cadherin, promotes epithelial-to-mesenchymal transition (EMT) and invasion.</p> Signup and view all the answers

<p>The ECM provides a substrate for cell movement and acts as a signaling platform, influencing cell behavior.</p> Signup and view all the answers

<p>Tumor cells can degrade the ECM using enzymes like matrix metalloproteinases (MMPs), creating invasive pathways and releasing growth factors bound to ECM components.</p> Signup and view all the answers

<p>The actin cytoskeleton drives protrusion and contractility, enabling cells to move forward and retract their rear ends.</p> Signup and view all the answers

<p>Lamellipodia are sheet-like protrusions that probe the environment and push the cell forward. Filopodia are finger-like projections that sense directional cues. Stress fibers generate contractile force and support cell rear retraction.</p> Signup and view all the answers

<p>Rho GTPases act as molecular switches regulating actin cytoskeleton dynamics, influencing cell shape, adhesion, and motility.</p> Signup and view all the answers

<p>Rac1 promotes lamellipodia formation, facilitating actin polymerization at the leading edge. RhoA regulates stress fiber formation and focal adhesion maturation, contributing to rear retraction. Cdc42 promotes filopodia formation, coordinating polarity during migration.</p> Signup and view all the answers

<p>The two main cell types are the parenchyma, which constitutes the tumor cells themselves, and the stroma, which includes surrounding connective tissue support cells, immune cells, and vasculature.</p> Signup and view all the answers

<p>Integrin binding to the ECM activates downstream signaling pathways, including the focal adhesion kinase (FAK) and the Src kinase, leading to increased cell survival, proliferation, and migration.</p> Signup and view all the answers

<p>MMPs are proteases that degrade the ECM, facilitating invasion and metastasis. TIMPs are inhibitors of MMPs, which can limit tumor cell invasion.</p> Signup and view all the answers

<p>This theory suggests that successful metastasis depends on a productive interaction between cancer cells (the seed) and the surrounding tissues (the soil) which provide appropriate growth factors and ECM components.</p> Signup and view all the answers

<p>EMT is a process where epithelial cells lose their epithelial characteristics and acquire mesenchymal features, such as motility and invasiveness. This transition is often associated with increased metastatic potential.</p> Signup and view all the answers

<p>Cancer cells often spread to specific sites based on factors such as venous and lymphatic drainage patterns, as well as the presence of body cavities that allow tumor cells to shed and metastasize.</p> Signup and view all the answers

<p>Challenges include difficulty in replicating human metastasis in animal models. To address this, experimental systems have been developed, such as using fragments of human bone implanted into immunocompromised mice for studying bone metastasis.</p> Signup and view all the answers

<p>Motility</p> Signup and view all the answers

<p>MMPs require zinc for activity</p> Signup and view all the answers

<p>B-catenin is a transcription factor involved in regulating gene expression. During EMT, loss of E-cadherin frees B-catenin, leading to increased levels of B-catenin and altered transcription of genes crucial for cell proliferation, differentiation, and other processes.</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>Expression of cadherins</p> Signup and view all the answers

<p>Implanting fragments of human bone into immunocompromised mice and injecting human prostate cancer cells</p> Signup and view all the answers

<p>Integrins = Mediate cell-matrix interactions Cadherins = Maintain cell-cell adhesions MMPs = Degrade the ECM TIMPs = Inhibit MMP activity</p> Signup and view all the answers