Targeting the MAP kinase pathway in astrocytoma cells using a recombinant anthrax lethal toxin as a way to inhibit
Saleh Al-Dimassi1, Gilbert Salloum1, Bechara Saykali1
1Department of Natural Sciences, The Lebanese American University, Beirut 1102 2801, Lebanon.
Abstract:
Malignant astrocytomas are highly invasive into adjacent and distant regions of the normal brain. Understanding and targeting cancer cell invasion is an important therapeutic approach. Cell invasion is a complex process that replies on many signaling pathways including the mitogen-activated protein (MAP) kinase (MAPK). In many cell lines, the use of MAPK-targeted drugs proved to be a potential method to inhibit cancer cell motility. In the present study, we use a recombinant anthrax lethal toxin (LeTx), which selectively inhibits the MAPK pathway, in order to target invasion. LeTx proved ineffective on cell survival in astrocytoma (as well as normal cells). However, astrocytoma cells that were treated with LeTx showed a significant decrease in cell motility as seen by wound healing as well as random 2D motility in serum. The cells also showed a decrease in invasion across a collagen matrix. The effect of LeTx on cell migration was mediated though the deregulation of Rho GTPases, which play a role in cell motility. Finally, the effect of LeTx on cell migration and Rho GTPases was mimicked by the inhibition of the MAPK pathway. In this study, we describe for the first time the effect of the LeTx on cancer cell motility and invasion not cell survival making it a potentially selective brain tumor invasion inhibitor.
Insights
Anthrax lethal toxin (LeTx) selectively inhibits the mitogen-activated protein (MAP) kinase pathway, reducing malignant astrocytoma cell invasion and motility without affecting cell survival. This offers a potential new strategy for brain tumor treatment.
Area of Science:
- Neuro-oncology
- Molecular Biology
- Cancer Therapeutics
Background:
- Malignant astrocytomas exhibit high invasiveness, posing a significant challenge in brain tumor treatment.
- Targeting cancer cell invasion is a crucial therapeutic strategy.
- The mitogen-activated protein (MAP) kinase (MAPK) pathway is implicated in cancer cell motility and invasion.
Purpose of the Study:
- To investigate the effect of anthrax lethal toxin (LeTx) on malignant astrocytoma cell invasion and motility.
- To determine if LeTx can selectively target cancer cell invasion without impacting cell survival.
Main Methods:
- Utilized recombinant anthrax lethal toxin (LeTx) to selectively inhibit the MAPK pathway in astrocytoma cells.
- Assessed cell motility using wound healing and random 2D motility assays.
- Evaluated cell invasion across a collagen matrix.
- Investigated the role of Rho GTPases in LeTx-mediated effects.
- Compared LeTx effects with direct MAPK pathway inhibition.
Main Results:
- LeTx did not affect the survival of astrocytoma or normal cells.
- LeTx treatment significantly decreased astrocytoma cell motility and invasion across a collagen matrix.
- LeTx-induced inhibition of cell migration was mediated by the deregulation of Rho GTPases.
- The observed effects of LeTx on migration and Rho GTPases were consistent with MAPK pathway inhibition.
Conclusions:
- Anthrax lethal toxin (LeTx) effectively inhibits malignant astrocytoma cell invasion and motility.
- LeTx demonstrates selectivity by targeting invasion pathways rather than cell survival.
- LeTx represents a potential novel therapeutic agent for selective brain tumor invasion inhibition.
