Related Experiment Video

Updated: Oct 7, 2026

RhoC GTPase Activation Assay
09:58

RhoC GTPase Activation Assay

Published on: August 22, 2010

Small GTP-binding protein, Rho, both increased and decreased cellular motility, activation of matrix

Y Matsumoto1, K Tanaka, K Harimaya

  • 1Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan.

Japanese Journal of Cancer Research : Gann
|May 11, 2001
PubMed

Insights

Lysophosphatidic acid (LPA) exhibits a dual role in osteosarcoma cell invasion, with low concentrations promoting motility and invasion, while high concentrations inhibit these processes by modulating the Rho-ROCK pathway.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Cancer Research

Background:

  • Rho GTPases and their effector ROCK are crucial for tumor cell invasion.
  • Lysophosphatidic acid (LPA) signaling through Rho and ROCK influences cell behavior, but its effect on tumor invasion is debated.
  • Osteosarcoma is a bone cancer where understanding invasion mechanisms is critical.

Purpose of the Study:

  • To investigate the concentration-dependent effects of LPA on human osteosarcoma cell invasion.
  • To elucidate the role of the Rho-ROCK pathway in LPA-mediated osteosarcoma cell invasion.
  • To determine how LPA affects extracellular matrix degradation and focal adhesion kinase (FAK) phosphorylation in osteosarcoma cells.

Main Methods:

  • Treatment of human osteosarcoma cells with varying concentrations of LPA.
  • Inhibition of Rho and ROCK pathways using C3 and Y27632, respectively.
  • Assessment of cell motility, invasion, matrix metalloproteinase 2 (MMP2) activation, and tyrosine phosphorylation of FAK.

Main Results:

  • Low LPA concentrations enhanced osteosarcoma cell motility and invasion, while high LPA concentrations reduced them.
  • LPA's effects were mediated through the Rho-ROCK pathway, as confirmed by inhibitor studies.
  • High LPA suppressed MMP2 activation by down-regulating MT1-MMP and TIMP2, and reduced FAK tyrosine phosphorylation, while low LPA enhanced it.

Conclusions:

  • Rho exhibits a dual role in osteosarcoma cell invasion, dependent on LPA concentration.
  • The Rho-ROCK pathway is a key regulator of LPA's effects on cell motility, ECM degradation, and FAK phosphorylation in osteosarcoma.
  • Targeting the Rho-ROCK pathway could offer therapeutic strategies for osteosarcoma by modulating invasion.

More Related Videos

Detection of Small GTPase Prenylation and GTP Binding Using Membrane Fractionation and GTPase-linked Immunosorbent Assay13:51

Detection of Small GTPase Prenylation and GTP Binding Using Membrane Fractionation and GTPase-linked Immunosorbent Assay

Published on: November 11, 2018

Induction of Mesenchymal-Epithelial Transitions in Sarcoma Cells11:42

Induction of Mesenchymal-Epithelial Transitions in Sarcoma Cells

Published on: April 7, 2017

Related Concept Videos

Small GTPases - Ras and Rho01:24

Small GTPases - Ras and Rho

Ras and Rho are small monomeric GTPases that act downstream of receptor tyrosine kinase (RTK) and regulate various cellular processes. These GTPases switch between active and inactive states by binding to guanine nucleotides.
Three regulatory proteins control their activity:
Cell Polarization by Rho Proteins01:21

Cell Polarization by Rho Proteins

Cell polarity is the asymmetric distribution of cellular and membrane components, making one side of the cell different from the other. This polarity is essential to many processes such as embryogenesis, axon migration, glucose transport across epithelial cells, and directional cell migration. A migrating cell responds to intracellular or extracellular signals via molecular cascades that reorganize the actin cytoskeleton to establish this polarity. In these cells, the Rho family proteins Cdc42,...
The Ras Gene02:38

The Ras Gene

The Ras-gene-encoded proteins are regulators of signaling pathways controlling cell proliferation, differentiation, or cell survival. The Ras-gene family in humans constitutes three primary members—the HRas, NRas, and KRas. These genes code for four functionally distinct yet closely related proteins—the HRas, NRas, KRas4A, and KRas4B. The involvement of mutant Ras genes in human cancer was first discovered in 1982 and is among the most common causes of human tumorigenesis.
Ras is a superfamily...
mTOR Signaling and Cancer Progression03:03

mTOR Signaling and Cancer Progression

The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
Activation and Inactivation of G Proteins01:22

Activation and Inactivation of G Proteins

Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high affinity and are together...
GTPases and their Regulation02:14

GTPases and their Regulation

Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell signaling, vesicular transport, and the regulation of cell shape and motility. Mutation or dysfunction of these proteins can lead to disease. There are around 40,000 known G-proteins that can broadly be classified into two groups ‒  small G-proteins consisting of a single domain and large multi-domain G-proteins.
Large G-proteins, also known...