BRAF/MEK Trial – Original tumors nearly gone BUT he has new tumors???

Hi

Maybe the lump to just a reaction to BRAK/MEK drug.

How is Eric's infection?

Stay strong.

Jan

Hi

Maybe the lump to just a reaction to BRAK/MEK drug.

How is Eric's infection?

Stay strong.

Jan

I wonder if its possible these tumors have different pathways other than braf/mek or if those tumors are just resistant to the braf/mek inhibitors?  Hopefully someone with some experience can reply with their input.  Wishing you guys the best.

-patrick

I wonder if its possible these tumors have different pathways other than braf/mek or if those tumors are just resistant to the braf/mek inhibitors?  Hopefully someone with some experience can reply with their input.  Wishing you guys the best.

-patrick

Sad to say, yes. 

Dr. Keith Flaherty spoke of this.

"When exposed to the drugs, the cells died off dramatically only to grow back again. In fact, cells that became resistant to one type of drug became resistant to all of them, which suggests that the cells were biochemically "rewired" in such a way that they no longer needed BRAF to form tumors.

"Knocking out mutant BRAF shuts a major pathway down, but if some cells can use an alternate pathway, then they can survive."

To find out which alternate pathways the drug-resistant cells use, Villanueva and her colleagues looked for signs of increased activation among proteins along the pathways BRAF uses, as well as other pathways.

Their hunt turned up two paths that worked together to aid survival. First, they found that resistant cells used a protein similar to BRAF to carry the signal down the chain. Second, they found these cells received an additional boost from the IGF-1 receptor, a protein that sits on the surface of cells and sends signals that prevent cells from being killed. The resistant cells re-route the signal around BRAF by switching to an alternate protein (CRAF or ARAF), which promotes tumor cell growth, while IGF-1R signaling promotes survival of the resistant cells.

Fortunately, there are a number compounds in clinical development that could block signals along both these pathways. So-called MEK inhibitors target a protein along the same pathway as BRAF, and IGF-1 receptor inhibitors (and inhibitors of P13K, a protein that can be activated by the IGF-1 receptor pathway) block the cancer-enabling survival signal. To test these drug combinations in the BRAF-inhibitor resistant cells, the Herlyn laboratory used a tool they developed to simulate the real-world environment of human cells: 3-D melanoma tumor spheroids. Their 3-D tissue cultures allow melanoma cells to grow in all directions, much like a new melanoma tumor would grow after metastasis. As predicted, a combination of these two inhibitors killed BRAF-resistant melanoma cells in the Wistar 3-D model.

Moreover, the Herlyn laboratory confirmed in tissue samples from patients in the PLX4032 trial — taken both before treatment and after they developed resistance — that an increased expression of the IGF-1 receptor is associated with resistance to BRAF inhibitors. None of the laboratory-generated cell lines or the post-relapse patient's tumor samples analyzed had new mutations in the BRAF, NRAS, or c-Kit genes.

Additionally, the researchers noted an association between the loss of a tumor suppressor called PTEN, and resistance to BRAF inhibitors in melanoma cell lines. The scientists found that the relapsed tumor of one patient included in the study lost the PTEN gene, even though it was present before treatment. These findings suggest that loss of PTEN could be an additional way that melanoma cells gain resistance to BRAF inhibitors. The Wistar group continues to investigate these and other mechanisms of resistance, as they expect that several will likely arise given the heterogeneous nature of melanoma.

"Tumors are efficient engines of evolution — they are going to find a way around most treatments, so we want to kill all the malignant cells from the very beginning," said Villanueva. "By targeting both pathways simultaneously you hit these cells with two punches from which they cannot recover."

"If you do this at the outset of treatment, we reason, it will prevent melanoma survival and hopefully improve patient outcomes," Villanueva added.

Support for this study was provided by grants from the National Cancer Institute and the Dr. Miriam and Sheldon G. Adelson Medical Research Foundation.

Wistar co-authors in this study include Adina Vultur, Ph.D.; John T. Lee, Ph.D.; Rajasekharan Somasundaram, Ph.D.; Mizuho Fukunaga-Kalabis, M.D., Ph.D.; Angela K. Cipolla; James E. Hayden; and Ademi E. Santiago-Walker, Ph.D. University of Pennsylvania School of Medicine co-authors include Katherine L. Nathanson, M.D.; Xiaowei Xu, M.D., Ph.D.; Phyllis A. Gimotty, Ph.D.; Bradley Wubbenhorst; Richard Letrero; Kurt D'Andrea; and Anitha Pushparajan. Other authors included Grant A. McArthur, M.B., B.S., Ph.D.; and Damien Kee, MBBS, FRACP, of the Peter MacCallum Cancer Centre in Victoria, Australia; Jeffrey A. Sosman, M.D., and Kimberly Dahlman Brown of the Vanderbilt University Medical Center; and Sylvie Laquerre, Ph.D., of GlaxoSmithKline's division of Oncology Biology in Collegeville, Pa.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

Source:http://www.sciencemagnews.com/killing-drug-resistant-melanoma-requires-combination-therapy.html

Sad to say, yes. 

Dr. Keith Flaherty spoke of this.

"When exposed to the drugs, the cells died off dramatically only to grow back again. In fact, cells that became resistant to one type of drug became resistant to all of them, which suggests that the cells were biochemically "rewired" in such a way that they no longer needed BRAF to form tumors.

"Knocking out mutant BRAF shuts a major pathway down, but if some cells can use an alternate pathway, then they can survive."

To find out which alternate pathways the drug-resistant cells use, Villanueva and her colleagues looked for signs of increased activation among proteins along the pathways BRAF uses, as well as other pathways.

Their hunt turned up two paths that worked together to aid survival. First, they found that resistant cells used a protein similar to BRAF to carry the signal down the chain. Second, they found these cells received an additional boost from the IGF-1 receptor, a protein that sits on the surface of cells and sends signals that prevent cells from being killed. The resistant cells re-route the signal around BRAF by switching to an alternate protein (CRAF or ARAF), which promotes tumor cell growth, while IGF-1R signaling promotes survival of the resistant cells.

Fortunately, there are a number compounds in clinical development that could block signals along both these pathways. So-called MEK inhibitors target a protein along the same pathway as BRAF, and IGF-1 receptor inhibitors (and inhibitors of P13K, a protein that can be activated by the IGF-1 receptor pathway) block the cancer-enabling survival signal. To test these drug combinations in the BRAF-inhibitor resistant cells, the Herlyn laboratory used a tool they developed to simulate the real-world environment of human cells: 3-D melanoma tumor spheroids. Their 3-D tissue cultures allow melanoma cells to grow in all directions, much like a new melanoma tumor would grow after metastasis. As predicted, a combination of these two inhibitors killed BRAF-resistant melanoma cells in the Wistar 3-D model.

Moreover, the Herlyn laboratory confirmed in tissue samples from patients in the PLX4032 trial — taken both before treatment and after they developed resistance — that an increased expression of the IGF-1 receptor is associated with resistance to BRAF inhibitors. None of the laboratory-generated cell lines or the post-relapse patient's tumor samples analyzed had new mutations in the BRAF, NRAS, or c-Kit genes.

Additionally, the researchers noted an association between the loss of a tumor suppressor called PTEN, and resistance to BRAF inhibitors in melanoma cell lines. The scientists found that the relapsed tumor of one patient included in the study lost the PTEN gene, even though it was present before treatment. These findings suggest that loss of PTEN could be an additional way that melanoma cells gain resistance to BRAF inhibitors. The Wistar group continues to investigate these and other mechanisms of resistance, as they expect that several will likely arise given the heterogeneous nature of melanoma.

"Tumors are efficient engines of evolution — they are going to find a way around most treatments, so we want to kill all the malignant cells from the very beginning," said Villanueva. "By targeting both pathways simultaneously you hit these cells with two punches from which they cannot recover."

"If you do this at the outset of treatment, we reason, it will prevent melanoma survival and hopefully improve patient outcomes," Villanueva added.

Support for this study was provided by grants from the National Cancer Institute and the Dr. Miriam and Sheldon G. Adelson Medical Research Foundation.

Wistar co-authors in this study include Adina Vultur, Ph.D.; John T. Lee, Ph.D.; Rajasekharan Somasundaram, Ph.D.; Mizuho Fukunaga-Kalabis, M.D., Ph.D.; Angela K. Cipolla; James E. Hayden; and Ademi E. Santiago-Walker, Ph.D. University of Pennsylvania School of Medicine co-authors include Katherine L. Nathanson, M.D.; Xiaowei Xu, M.D., Ph.D.; Phyllis A. Gimotty, Ph.D.; Bradley Wubbenhorst; Richard Letrero; Kurt D'Andrea; and Anitha Pushparajan. Other authors included Grant A. McArthur, M.B., B.S., Ph.D.; and Damien Kee, MBBS, FRACP, of the Peter MacCallum Cancer Centre in Victoria, Australia; Jeffrey A. Sosman, M.D., and Kimberly Dahlman Brown of the Vanderbilt University Medical Center; and Sylvie Laquerre, Ph.D., of GlaxoSmithKline's division of Oncology Biology in Collegeville, Pa.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

Source:http://www.sciencemagnews.com/killing-drug-resistant-melanoma-requires-combination-therapy.html