Since then, several rapamycin analogs known as mTOR (mammalian target of rapamycin) inhibitors have been tested in clinical trials for the treatment of various types of cancer.
But despite promising early results, mTOR inhibitors have proven less successful than originally expected.
Now research led by scientists at Beth Israel Deaconess Medical Center (BIDMC) identifies a previously unrecognized problem faced by these agents when it comes to attacking cancers. Reported in the August 21 advance on-line issue of The Journal of Clinical Investigation (JCI), the new findings show that at the same time that rapamycin analogs are halting tumor growth by inhibiting the mTOR protein complex 1 (mTORC1), they are activating the MAPK (mitogen-activated protein kinase) pathway -- thereby encouraging cancer cell survival.
"Anticancer research is aimed at understanding the molecular pathways that can be selectively targeted to halt tumor growth," explains senior author Pier Paolo Pandolfi, MD, PhD, Director of Basic Research of the Cancer Center at BIDMC and Professor of Medicine at Harvard Medical School. "We know that the mTOR pathway is activated in many cancers, and therefore, is a good target for fighting a wide array of tumors."
The mTOR pathway controls cell growth and angiogenesis through a series of mechanisms that integrate signaling from nutrients and other growth-promoting pathways. Activation of mTOR, therefore, promotes the proliferation of tumor cells, while inhibition of mTOR counters this action. However, because the mTOR signaling pathway is extremely complex, scientists have focused their efforts on identifying other agents that could be successfully combined with mTOR inhibitors to halt cancer growth.
The new findings shine a light on MAPK, a signaling pathway also known for its role in sensing growth factors to promote cell survival and proliferation.
"We analyzed tissue from human biopsies, as well as cancer cell lines and genetically engineered mouse models of cancer," explains the study's first author Arkaitz Carracedo, PhD, a postdoctoral fellow in the Pandolfi laboratory. "These experiments all pointed to the MAPK pathway."
From there, Carracedo and his coauthors went on to test a group of MAPK inhibitor agents to find out if, in combination with mTOR inhibitors, the agents would act to counter any pro-survival activity. And they did.
"This study inserts a new piece of information into the puzzle of the effects of mTORC1 inhibitors in cell signaling," says Pandolfi. "Furthermore, because there are inhibitors of MAPK pathway already approved for the treatment of cancer, it provides us with the rationale for using combinations of mTORC1 and MAPK inhibitors in attacking tumors, thereby offering cancer patients another treatment option with immediate applicability."
Bonnie Prescott | EurekAlert!
Turning carbon dioxide into liquid fuel
06.08.2020 | DOE/Argonne National Laboratory
Tellurium makes the difference
06.08.2020 | Friedrich-Schiller-Universität Jena
Scientists at the Fraunhofer Institute for Laser Technology ILT have come up with a striking new addition to contact stamping technologies in the ERDF research project ScanCut. In collaboration with industry partners from North Rhine-Westphalia, the Aachen-based team of researchers developed a hybrid manufacturing process for the laser cutting of thin-walled metal strips. This new process makes it possible to fabricate even the tiniest details of contact parts in an eco-friendly, high-precision and efficient manner.
Plug connectors are tiny and, at first glance, unremarkable – yet modern vehicles would be unable to function without them. Several thousand plug connectors...
An international research team has found a new approach that may be able to reduce bone loss in osteoporosis and maintain bone health.
Osteoporosis is the most common age-related bone disease which affects hundreds of millions of individuals worldwide. It is estimated that one in three women...
Traditional single-cell sequencing methods help to reveal insights about cellular differences and functions - but they do this with static snapshots only...
“Core-shell” clusters pave the way for new efficient nanomaterials that make catalysts, magnetic and laser sensors or measuring devices for detecting electromagnetic radiation more efficient.
Whether in innovative high-tech materials, more powerful computer chips, pharmaceuticals or in the field of renewable energies, nanoparticles – smallest...
An international research team with Prof. Cornelia Denz from the Institute of Applied Physics at the University of Münster develop for the first time light fields using caustics that do not change during propagation. With the new method, the physicists cleverly exploit light structures that can be seen in rainbows or when light is transmitted through drinking glasses.
Modern applications as high resolution microsopy or micro- or nanoscale material processing require customized laser beams that do not change during...
23.07.2020 | Event News
21.07.2020 | Event News
07.07.2020 | Event News
06.08.2020 | Earth Sciences
06.08.2020 | Power and Electrical Engineering
06.08.2020 | Life Sciences