It takes two (IL-2) to Tango! Melanoma..Jim Breitfeller

Immune responses involve multiple cell-cell interactions within lymphoid tissues, the
trafficking of activated cells to sites of effector function, and the migration of such effector cells within peripheral tissues. To gain a more detailed appreciation of the dynamics of such cell behavior and the relationship between cell dynamics and function, I have put together a series of events that take place during the activation phase of the immune response.


We know based on research that once the CD4+ T cell is activated, within two hours the IL-2 expression and IL-2 receptor are unregulated. IL-2 is secreted 45 minutes into this activation phase.



Experimental work has shown that IL-2 signaling in the first 10 hours is critical for the proliferation decision of T cells in culture. The spacial resolution of the Tregs and the T helper cells during this phase plays a major part in the immune response.
Secreted IL-2 is competed for by the Tregs and the activated CD4+ and CD8+ T-cells. If the Tregs are in close proximity of the T effector cells that are secreting the IL-2, the Tregs will create an IL-2 sink in the microenvironment. This will cause the proliferation and survival of the Tregs which suppresses the effector cell function. The IL-2 sink is where all the IL-2 that is secreted by the T helper cells is adsorbed by the IL-2 receptors on the Treg cells. Tregs don’t have the capability to produce IL-2 so they must scavenge the IL-2 out of the microenvironment of the CD4+ T helper cells. In Treg cells, the IL-2 gene is silenced and IL-2Rα is constitutively expressed through the action of the Treg-lineage-specifying transcription factor FoxP3.

The model proposed by Dr. Dorothea Busse and colleages predicts that the IL-2 secretion rate must exceed a threshold value Theta (θ) to switch IL-2Rα expression to the activated state and permit extensive autocrine IL-2 signaling.

This is just like the three little bears. You need the microenviroment conditions just right to activate T Helper cells.




As you can see in the above diagram, you don’t need high concentration of IL-2, you need spacial distance from one cell to the other. That can be achieved by Anti-CTLA-4 Blockage. By blocking the CTLA-4 receptors, the spacial distance between the T helper cell and the Treg cells increases and it also helps to differentiate the niave CD4+ T cells into Th17 cells.

IL-2 is mainly captured by the Treg cell, whereas autocrine reuptake by the T helper cells predominates when the cells are further apart. So we want to introduce IL-2 before the tumor recruites the Tregs to the Tumor Microenviroment and or when the Treg population is in the contration phase of the CD4+ T-cell cycle.




Cellular signal response is potentially controlled by ratio between ligand (IL-2)
number and surface receptor (IL-2R) number per cell.

Ligand n. An ion, a molecule, or a molecular group that binds to another chemical entity to form a larger complex.
.

Suboptimal amounts of IL-2 during priming promoted apoptosis, little proliferation and cell cycling, yet the CD8+ effectors generated produced high levels of cytokines and proliferated autonomously. Although IL-2 deprivation caused apoptosis and little proliferation initially, the effectors generated under these conditions possessed optimal effector functions. This low IL-2 concentration, allows the T help cell to activate and proliferate.
This is the reason why it takes a while for the tumors to begin to shrink because of little proliferation at first. It takes time for the immune system to assemble an army of Cytotoxic T Lymphocytes.


So how can we minimize the proliferation of the Tregs which are a subset of CD4+ T-cell subset without doing a full blown depletion of the CD4+ T-cells?

1. Anti-CTLA-4 Blockage
2. Local IL-21 Promotes the Therapeutic Activity of Effector T cells by
Decreasing Regulatory T Cells Within the Tumor Microenvironment
3. Anti-PD-1 Blockage
4. A combination of the above three.



This is the future of Melanoma Therapy, Combinatorial Therapy.




“It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.”
~Charles Darwin~

Take Care,
Jimmy B

The missing third signal "The Danger Signal"Melanoma..Jim Breitfeller

Th17 Cells Secrete IL-17 in the Tumor Microenvironment causing inflammatory symptoms "The Danger Signal"improves Survival in a Murine Model of Pancreatic Cancer and in Melanoma also.

Third, inflammatory cytokines, including IL-1, IL-6, IL-12, and IFN-γ provide a third signal that acts directly on T cells, referred to as the “danger signal”. This signal was found to optimally activate TH1 differentiation and lead to clonal expansion of T cells.

"Th17 cells and IL-17 participate in antitumor immunity by facilitating T cell recruitment to the tumor site and CD8+ T cell priming and effector differentiation suggests a new avenue for developing Th17 cell-based therapy."

~S. A. Rosenberg~


"Using in vitro and in vivo approaches, we determined that under neutral conditions, simultaneous activation of Tregs and naive CD4+ conventional T cells in the presence of APCs resulted in conversion of Tregs into IL-17–producing cells, and endogenous IL-1β was mandatory in this process" according to Vassiliki A. Boussiotis et al



Thus, the addition of IL-6 and IL-1β to the tumor microenvironment skews the balance toward Th17 cells in a murine model of pancreatic cancer and Melanoma.

So we need to suppress the Tregs and generate Th17 T-cells to initiate the right immune response.




“It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.”
~Charles Darwin~
Take Care,
Jimmy B

The Orchestration of an Immune Response Unrehearsed! Melanoma..Jim Breitfeller

February 4 is World Cancer Day—a global day of awareness created by the International Union Against Cancer. With cancer set to become the #1 killer in the world this year, the day brings us together to highlight the growing personal and economic impact of the disease. On this day it’s critical that each organization—and each individual—share responsibility for sending a powerful message about cancer prevention.





















Melanoma And the Magic Bullet (monoclonal Antibodies



Take Care,

Jimmy B

Eureka!!!!!! A possible cure for Melanoma, the Deadly Skin Cancer..Jim Breitfeller

Eureka!!!!!! A possible cure for Melanoma, the Deadly Skin Cancer.
Jim Breitfeller, a patient/survivor/researcher of Matastatic Melanoma has so far beaten the odds of survival. After years of researching his own treatment, he has scientifically figured out why his treatment has worked. Jim explains it like this:

“You need the tumor specific antigens, (The Keys), you need the (Spark Plug) Anti-CTLA-4 and you need the (Gas) IL-2. Without these three key components your car won’t run.”

CTLA4 Role in Immune Function
Cytotoxic T Lymphocyte-Associated Antigen 4 (CTLA4) is a protein involved in T-cell expansion or replication and activation in response to an immune event. Following T-cell stimulation, T-cell proliferation is up-regulated. Following successful response, CLTA4 is also up-regulated, which then sends an inhibitory signal to down-regulate or decrease T-cell proliferation and IL-2 production. This is one of the brakes associated with immune system so it won’t go into overdrive and create a possible autoimmune event.
In the presence of the tumor’s microenvironment, the CTLA4 molecule is upregulated on the T-Cells with the help of TGF-beta, a suppressive Cytokine secreted by the tumor cells. TGF-beta requires CTLA-4 early after T-Cell Activation to Induce FoxP3 and generates adaptive CD4+CD25+ Regulatory Cells. et al Song Guo Zheng and colleagues.





If you add the combination of IL-2 and TGF- beta at the beginning of the treatment, it induces naive or total CD4+CD25– cells to develop strong suppressive effects both in vitro and in vivo according to Horwitz et al 2001. The T-Cell differentiation is pushed towards developing Treg suppressive immune cells.





Anti-CTLA4 monoclonal antibodies block the ability of CTLA4 molecule to down-regulate T cell proliferation. The theory behind this therapy is that by decreasing the inhibitory signal, there will be a subsequent increase in the number of activated T-cells available, to improve the ability of the T-cells to recognize melanoma cells as non-self.
Tregs show remarkably suppressive activities on different components of the immune system, including T lymphocytes and dendritic cells, suggesting they act both at the initiation phase (DC) and at the effector phase (activated T cells) of the immune response. Interestingly, temporal depletion of Treg has been shown to enhance anti-tumor immune responses and in case of prolonged absence of Treg even autoimmunity.





The green boxes show possible Therapeutic Intervention,



By blocking the CTLA-4 receptor, you keep the T-cell activated, you push the T-cell differentiation towards the TH17 cells and you now have that the Third signal, (The inflammatory signal) that is needed to induce an Immune response. et al Ribas






By adding the HD IL-2 after the expansion of the T-cells, IL-2 therapy was highly beneficial during the death phase, resulting in increased proliferation and survival of tumor-specific T cells. IL-2 treatment also increased proliferation of resting memory T cells. et al Wherry


CTLA-4 blockade in cancer immunotherapy.


Dendritic cells can sample tumor antigens and present them to T cells. (A) Although activation of dendritic cells may result in upregulation of B7.1/B7.2, the potentially responsive T cells expressing reactive TCR may be inhibited from effector function by inhibitory signaling via CTLA-4 and PD-1.


Blockade of CTLA-4 signaling may allow unopposed CD28 costimulation, resulting in recruitment of these T cells as antitumor effectors, either directly or as helpers of CD8-mediated T cells responses. Activated cytotoxic T cells can then affect antitumor responses. CTLA-4 expressing regulatory T cell populations may still be locally active in suppressing antitumor responses. Their activity could also be directly downregulated by CTLA-4 blockade, although the relative importance of CTLA-4 expression to their function remains controversial.


Recent research by Probst et al reveal that resting dendritic cells induce peripheral CD8+ T-cell tolerance through the PD-1 and the CTLA-4 molecule/surface receptor. Blocking the costimulatory molecule CTLA-4 resulted in breaking the tolerance.



When you put the Melanoma Puzzle together, this is what you get,


A well Orchestrated Event, your immune system in action.








The Perfect Storm, the Orchestration of an Immune Response Unrehearsed







• Early after the CD4+ T-cells are activated, the CTLA-4 receptors are upregulated according to the research.

• TGF- beta requires CTLA-4 upregulation early after T Cell Activation to Induce FoxP3 and generate adaptive CD4+CD25+ Regulatory Cells. Song Guo Zheng et al and colleagues.

• By blocking the CTLA-4 receptor, you keep the T-cell activated, you push the T-cell differentiation towards the TH17 cells and you now have that the Third signal, (The inflammatory signal) that is needed to induce an Immune response. Ribas et al

• If you add the combination of IL-2 and TGF- beta at the beginning of the treatment,it induces naive or total CD4+CD25– cells to develop strong suppressive effects both in vitro and in vivo according to Horwitz et al in 2001.

• By adding the The HD IL-2 after the expansion of the T-cells, IL-2 therapy was highly beneficial during the death phase, resulting in increased proliferation and survival of tumor-specific T cells. IL-2 treatment also increased proliferation of resting memory T cells. Wherry et al




Here are some other papers I have written that puts the Melanoma Therapy into perspective.

Melanoma and the Magic Bullet [Monoclonal Antibodies]


The Making of an Immune Response by Combinatorial Therapy using Anti-CTLA-4 Blockade and Interluekin-2


Déjà vu Blame it on the tregs]



The Missing Link in T-cell Activation


Take Care,

Jimmy B

Signs, signs everywhere there are signs!!!! Melanoma ..Jim Breitfeller

"Depletion of TREG cells using CD25-specific (mAbs) monoclonal antibodies has been shown to promote rejection of several transplantable murine tumour cell lines, including melanoma, fibrosarcoma, leukaemia and colorectal carcinoma. These studies imply that TREG cells normally inhibit the generation of effective T cell-dependent anti-tumour immune responses. These finding have been confirmed in the clinical setting, where the prevalence of TREG cells was found to be increased in the peripheral blood and tumour microenvironment of cancer patients."

We just need to break the imbalance and generate an immune response.



"IL-2 has been shown to be essential for the generation of TREG cells in the thymus and their survival, expansion and suppressive function in
the periphery [69]. IL-2-, and IL-2R-deficient mice develop T-cell lympho-proliferation and lethal autoimmunity, very probably due to lack of
activation-induced cell death (AICD) and lack of T REG cells. Furthermore, in vivo IL-2 neutralisation by use of an IL-2 blocking antibody also induces autoimmune diseases in mice. The detailed molecular mechanisms of the effects of IL-2 in the homeostasis and suppressive function of TREG cells have still to be clarified."

Source:http://www.smw.ch/docs/pdf200x/2007/45/smw-11916.PDF

"CD4+CD25+Foxp3+ regulatory T cells: frombasic research to potential therapeutic use"

Christian Motteta, Dela Golshayanb
a Division of Gastroenterology & Hepatology, BH-10N-545, Centre Hospitalier Universitaire
Vaudois (CHUV), Lausanne, Switzerland
b Division of Nephrology & Transplantation Centre, Centre Hospitalier Universitaire Vaudois
(CHUV), Lausanne, Switzerland

Take care


Jimmy B

Cellular Immunotherapy I (Supressive cells in Cancer Patients) Melanoma ..Jim Breitfeller

In my research, I ran across this powerpoint presentation on Cellular Immunotherapy. I gave me a better understanding on what may be happening to Us cancer Patients.

It is from Tumor Genetics, Clinic I Internal Medicine
Center for Molecular Medicine Cologne Germany.

Please take time to Review it.
Source:http://www.zmmk.uni-koeln.de/content/seminare/lmm_08/common/lecture_cellular_immunotherapy_I.pdf

Cellular Immunotherapy I

Take care

Jimmy B

Tumors Evading Detection!!!!! Melanoma.. Jim Breitfeller

Tumors Evading Detection
Lack of costimulation:

Many Melanoma tumor cells do not have the B7 protein on their surface so this co-stimulatory second signal cannot take place. Theoretically, they should cause an immune response but they do not stimulate an effective anti-tumor immune response. The first signal originates from the binding of the T cell receptor (TCR) to its antigen-MHC, and provides the specificity of the interaction. Without this signal, the cell enters anergic state and can act as a T reg cell. Expression of B7 on the surface of a cell is the costimulatory signal necessary to allow for the cytolytic CD8+ T cell attack on the tumor. B7 display renders tumor cells capable of effective antigen presentation, leading to their eventual eradication.

Secretion of immunosuppressive cytokines:

Another way tumors evade detection is by secretion of certain cytokines. They are low-molecular weight proteins that use their communication ability to regulate the immune response. Cytokines can act upon either the cells secreting them (autocrine) or on neighboring cells (paracrine) to generate activities in the targeted cells. This means they can act as light switches for on and off immune responses. For example, interleukin-2 activates a cell-mediated immune response, while interleukin-10 suppresses cell-mediated responses. Many types of cancer, including Melanoma, take advantage of this ability to down regulate this appropriate immune response to help extend their survival and proliferation. This causes cancer patients to fail in mounting a successful attack on the tumors. Immunosuppressive cytokines secreted by cancer cells include transforming growth factor-beta (TGF-beta), interleukin-10 (IL-10) and vascular endothelial growth factor (VEGF).

TGF-beta is one of the most potent immunosuppressive cytokines characterized to date. It is capable of affecting the proliferation, activation and differentiation of cells participating in both the innate and acquired immune response.TGF-beta inhibits the profilation T-cells, B cells, Natural killer cells (NK), and macrophages.TGF-beta also converts T-cells, which normally attack cancer with an inflammatory (immune) reaction, into regulatory (suppressor) T-cells, which turn off the inflammatory reaction. Another of TGF-beta's affect is on cytotoxic T lymphocytes (CTLs) This is very important for anti-tumor immunity because of their cytotoxic effects. TGF-beta down-regulates many of the processes necessary for CTL activation. Without this activation, there is no assault on the tumor cells from the CTLs. In addition to suppressing proliferation, TGF-beta has been shown to induce apoptosis (cell death) in B and T cells.

Another immunosuppressive cytokine is IL-10. It is capable of inhibiting the prodction of of pro-inflammatory cytokines like IFN-gamma, IL-2, and GM-CSF made by cells such as macrophages and T helper cells. IL-10 also displays potent abilities to suppress the antigen presentation capacity of antigen presenting cells. Secretion of IL-10 in the vicinity of a tumor can render the tumor totally insensitive to CTL-mediated lysis. It is most likely that the tumor’s microenvironment is altered enough to block or turn off the discharge granules that would lyses the tumor cell. However, it is also stimulatory towards certain T cells, mast cells and B cells. It enhances B cell survival, proliferation, and antibody production. As you can see, IL-10 has many rolls to play when it come to the immune system.

The cytokine VEGF is produced by most tumors.
Vascular endothelial growth factor (VEGF) is a cytokine that is produced by most tumors. This growth factor enables the tumor to expand vascularly when is in its growth phase. VEGF production can be induced in tumor cells that are not receiving enough oxygen.

Regulatory T-cells (Tregs) (suppressor T cells) are a specialized subpopulation of T cells that act to suppress activation of the immune system and thereby maintain immune system homeostasis and tolerance to self-antigens.1

Tumor Growth kinetics

The cell cycle has four stages:

1. G1 phase when the cell increases in size and gets ready to replicate its DNA.
2. S phase when the cell synthesizes or copies its chromosomes
3. G2 phase in which the cell prepares to divide
4. M phase when mitosis occurs.

When the various growth inhibitory proteins and checkpoint controls which regulate this cycle become disabled due to mutations characteristic of cancerous cells, the cell cycle is no longer under tight regulation. Tumor cells are capable of proliferating so quickly that the immune response is not fast enough to keep their growth in check. The growth of the tumor cells outpaces the immune response and escape the detection of the immune system. Lack of cell cycle controls leads to excessive proliferation of tumor cells.





I am getting closer!!!!

Take care

Jimmy B

Hand and Hand Tumor Rejection ..Melanoma ..Jim Breitfeller

This diagram goes with the "Tumor Rejection Piece"


Tumor Rejection!!!!!!

To cause the rejection of the tumors cells, The immune system must orchestrate a chain of events mediated by several types of Leukocytes including Dendtric cells (DC), Natuaral Killer cells (NK), CD4+ and CD8+ lymphocytes and others. This orchestration has many players in it including the T-Regs, sercreted cytokines, and Monoclonal antibodies (mAb’s) and complexes. It is a delicate balance between self and non-self.

At the Lymph Node drainage area, the lymphocytes (CD4+ and CD8+) with their T-cell receptors (TCRs) are able to scan the Dendtric cells (DC’s) for antigen-MHC molecules. (ag-MHC) major histocompatability complex (class I or II). Based on the two signal model, a second signal from CD28 molecule is needed to activate the T-cells (T-lymphocytes). If communcation breaksdown, and the TCR signal only happens, it can lead to tolerance by means of fuctional paralysis of the (APCs) Antigen presenting cells (Anergy) or by the induction of clonal deletion (apoptosis). Anergic cells can act as regulatory T cells by competing at the sites of antigen presentation and adsorbing out stimulatory cytokines such as IL-2. This can halt the activation of the T- lymphocytes and no immune response is initiated.

Once activated fully, the CD4+ T-cells can mobilize to where the event will take place and usually sends out a “danger signal” inflammation. The activated CD4+ T-cells can secrete many different cytokines including IL-4, IL-2 and activate the TH2 cells which are a subset of the CD4+ cells. The TH2 cells stimulate the B cells to mature into plasma cells that secrete antibodies. These antibodies that are produced are the cell-destructive kinds that have anti-tumor behavior. The CD4+ can also cross-prime CD8+ T-cells in the presence of IL-2 and are called (CTLs)Cytotoxic T Lymphocytes. Cross-priming is another name for cross-presentation. The role of the CD8+ T cells is to monitor all the cells of the body, ready to destroy any that express foreign antigen fragments in their class I molecules.

Some CD4+ T cells can develop into CTLs, but they can attack only those cell types (e.g. B cells, macrophages, dendritic cells) that express class II MHC molecules. Virtually every cell in the body expresses class I MHC molecules, so CD8+ CTLs are not limited in the targets they can attack. CTLs have cytoplasmic granules that contain the proteins perforin and granzymes. When the CTL binds to its target, the contents of the granules are discharged. A dozen or more perforin molecules insert themselves into the plasma membrane of target cells forming a pore that enables granzymes to enter the cell. Granzymes are serine proteases. The serine proteases are a family of enzymes that cut certain bonds in other proteins. It is similar to what is in your laundry detergent. They are known as detergent enzymes. They break the bond between the dirt and the fabric. By breaking up these proteins, they start destroying the intracellular workings of the tumor cells.

Next Piece is how the tumor protects itself from the Killer T-cells through a microenviroment and Tregs.


Just plugging away!!

Jimmy B

Fewer, Smaller Skin Cancer Tumors After Blocking Protein Melanoma ..Jim Breitfeller

Main Category: Melanoma / Skin Cancer
Also Included In: Biology / Biochemistry; Vascular; Dermatology
Article Date: 18 Feb 2009 - 1:00 PST

New research suggests that blocking the activity of a protein in the blood could offer powerful protection against some skin cancers.

In the study, normal mice and mice that had a genetically engineered protein deficiency were exposed to almost a year of ultraviolet light that mimics chronic sun exposure. The mice that lacked the protein developed fewer, smaller, less aggressive and less vascular skin cancer tumors than did the normal mice.

Because a low-dose drug that blocks the protein's activity in the blood is currently under investigation by a Pennsylvania pharmaceutical company, the researchers hope that someday, a simple pill might help prevent or treat nonmelanoma skin cancer in people at highest risk for the disease.

Source:http://www.medicalnewstoday.com/articles/139335.php?nfid=76490

Micro RNA Plays A Key Role In Melanoma Metastasis..Jim Breitfeller

Adapted from materials provided by NYU Langone Medical Center / New York University School of Medicine.

ScienceDaily (Feb. 9, 2009) — Scientists have long wondered how melanoma cells travel from primary tumors on the surface of the skin to the brain, liver and lungs, where they become more aggressive, resistant to therapy, and deadly. Now, scientists from NYU Langone Medical Center have identified the possible culprit—a short strand of RNA called microRNA (miRNA) that is over-expressed in metastatic melanoma cell lines and tissues

Source:

RNA Plays A Key Role In Melanoma Metastasis


The new findings, published February 10, 2009 in the Proceedings of the National Academy of Sciences (PNAS), suggest that miRNA silencing to counteract or attack this mechanism may be an effective therapeutic strategy for metastatic melanoma, according to Eva Hernando, Ph.D., assistant professor in the Department of Pathology at NYU School of Medicine, and the lead author of the study. Dr. Hernando is also a member of the NYU Cancer Institute at NYU Langone Medical Center.

The highly aggressive character of melanoma, says Dr. Hernando, makes it an excellent model to probe the mechanisms underlying metastasis, the process by which cancer cells travel from the primary tumor to distant sites in the body. Though other researchers have found that altered miRNAs contribute to breast cancer metastasis, this is the first study to examine the role of miRNA in metastatic melanoma.

"Melanoma becomes deadly after the cells leave the primary tumor through the blood and metastasize in other organs where they are resistant to therapy," says Dr. Hernando, who notes that the average survival for patients after melanoma metastasis occurs is only nine months. "Normal cells are unable to travel and survive in alien locations, so we are very interested in understanding the invasive, adaptive, and resistant traits of the very aggressive melanoma cell." miRNAs are short pieces of RNA that block the expression of proteins that are encoded by messenger RNAs. They serve as regulators of protein expression, acting like the volume control on a radio. In recent years, miRNAs have been linked to the over- or under-expression of a variety of genes linked to cancer and other diseases.

Dr. Hernando's lab found a miRNA is over-expressed in metastatic melanoma cell lines and tissues. The lab found that the elevated expression of miRNA 182 turns it into an oncogene (a gene involved in cancer tumor initiation or progression), by increasing the invasive capacity of melanoma cells in vitro and stimulating the cell's metastatic potential in a mouse model.
In addition, the NYU scientists found that miRNA 182 also represses the expression of two tumor suppressors called FOXO3 and MITF, which normally prevent cells from becoming malignant. By repressing the suppressors, miRNA 182 permits melanoma cells to migrate and survive independently, two properties necessary for metastasis.

MiRNA 182 also belongs to a cluster located in a genomic region, chromosome 7q, that is frequently amplified in melanoma and contains two other oncogenes; BRAF and C-MET. The study found a correlation between genomic amplification and miRNA over expression, though it is unclear whether other molecular mechanisms play a role in this effect, according to Dr. Hernando.

Finally, the scientists observed that in a significant fraction of metastatic melanomas, high miRNA 182 levels correlate with low levels of FOXO3 and MITF, supporting the relevance of this mechanism in human melanoma.

The study suggests that miRNA 182 is a novel therapeutic target. When it is inhibited, it impairs the invasive potential of melanoma cells and induces cell death. In theory, the administration of anti-miRNA 182 could block the growth or expansion of the primary melanoma tumor. Several academic laboratories and pharmaceutical companies are working to improve the delivery of anti-miRNAs by using chemical modification and nano particles to increase their stability, specificity, and ability to reach tumors in sufficient doses with low toxicity.
The NYU Cancer Institute is currently studying whether anti-miRNA will work on miRNA 182 to inhibit the growth or spread of primary melanoma in mice. Dr. Hernando says that even if the anti-miRNA cannot do this on its own, it might work in combination with conventional chemotherapy or novel targeted therapies.

This study is the result of an extensive collaboration between members of NYU's Interdisciplinary Melanoma Cooperative Group, led by Iman Osman, M.D. , one of the study's co-authors, which has a large biospecimen bank comprising human tissue, blood and patient clinico-pathological information.

"The existence of this bank permits us to validate our laboratory findings using human tissue," says Dr. Hernando. "In this study, we began looking at cell lines and then at melanoma tissue. Now that the mechanism has been proven using cell lines and mice, the next step will be to perform in-vitro studies with cell lines to assess the effect of anti-miRNA on cell death in both normal and melanoma cells. Once that study is completed, we can use this model for studies in mice to block the growth of the primary melanoma tumor or the metastasis by using anti-miRNA. All these steps will determine if this approach could be eventually applied to humans."

Jimmy B

Melanoma – A Look Down The Road Ahead!! Jim Breitfeller

By Ze’ev Ronai, PhD, Burnham Institute for Medical Research, La Jolla, USA www.ronailab.net


"Malignant melanoma is one of the most highly invasive and metastatic tumors. Correspondingly, the primary clinical barriers to effective melanoma treatment are the high propensity for tumors to metastasize and the strong resistance of tumors to available treatments.

A significant advance in understanding melanoma biology was made over recent years when genetic changes along the MAPK signaling pathway (B-Raf and N-Ras mutations) were identified. Identification of these types of mutations in many melanoma tumors has significantly increased our understanding of genetic changes underlying melanoma. Yet, it is critical to note that identical genetic changes do not always underlie different melanoma subtypes. For example, mutations seen in melanomas associated with sun exposure differ from those seen in other subtypes, and some melanoma subtypes exhibit mutations in signaling pathways other than MAPK kinase. For example, c-Kit mutations were found in about 30% of mucosal, acral and other melanomas developing on chronically sun-exposed skin, conditions in which mutations in MAPK pathway components were not seen. Thus, while we have greatly advanced our understanding melanoma as a cancer marked by deregulation of well-defined signaling pathways, it is now clear that changes in multiple pathways exist among melanoma subtypes. Understanding these differences will dictate how selective therapies are developed and applied.

Adding to the complexity is the growing recognition that pathways are re-wired in melanoma. In tumors, MAPK-related pathways intersect with and influence regulatory pathways not thought to be linked in normal cells. Thus, the molecular analysis of changes in melanoma will require extensive dissection of multiple pathways influenced by deregulated genes. For example, further understanding of mechanisms underlying deregulated AKT signaling in melanoma awaits characterization.

Equally important is the growing realization that central to the etiology of melanoma is a small but potent population of melanoma initiating (stem?) cells. This exciting topic is receiving growing attention and should provide important insight into the handful of cells capable of initiating a tumor. Although currently only a few groups are dedicating their efforts to this exciting observation, an emerging theme in cancer research is that melanoma initiating cells may be as complex as melanoma tumors are.

Understanding tumor microenvironment has been and will remain critical to our understanding of melanoma progression, given that a hallmark of melanoma is its metastatic potential. The development of mouse models and better technologies to study tumor microenvironment (from 3D cultures to lymph-angiogenesis) provides tools necessary for identifying mechanisms underlying melanoma metastasis and finding selective means to halt it, as well as models to assess possible therapeutic approaches."


The rest of the article can be found at:

http://www.pigment.org/virtual.asp
Pigment Cell & Melanoma

Jimmy B

April 14, 2008 Pfizer Anti-CTLA4 antibody trial for melanoma stopped for futility ... Jim Breitfeller's point of View

April 14, 2008 Pfizer Anti-CTLA4 antibody trial for melanoma stopped for futility.

"The Data Safety Monitoring Board halted the Phase III randomized open label trial comparing the Pfizer anti-CTLA4 antibody, tremelimumab, to "standard" (and generally ineffective) chemotherapy for metastatic melanoma. The Board has reported that there is no statistical difference between the primary endpoint, overall survival, between the two study arms. Further, statistical analysis reportedly shows that further examination is "futile" or basically unlikely to ever show a statistical difference.

This is a major setback for the hopes of many investigators and patients who felt that the anti-CTLA4 antibodies represent an encouraging potential new therapy for metastatic melanoma, a disease for which there is no universally accepted or generally effective therapy.

Will this completely halt all efforts by Pfizer to develop this drug in melanoma?"

Authored by:
Eric Whitman, MD, is a Medical Director of the Office of Grants and Research for Atlantic Health System in Morristown, New Jersey

The A3671009 Phase III trial in 630 advanced melanoma patients was investigating tremelimumab compared to standard chemotherapy, consisting of dacarbazine and Schering-Plough's Temodar (temozolomide).

I for one, Believe it works but it must be in combination with Interluekin-2. See the Phase III trial was a administered as a single agent.

With my first hand experience, I did one cycle of CTLA-4 therapy and then switched to Interluekin-2. Base on the immune system pathway, the CTLA-4 blockage only activated one signal by attaching to the B7 receptor. It is all in the Medical literature. To get the Immune system to respond, it needs second signal (cell to cell). That is done with IL-2. It is my belief, that there must be time in between therapies to set the pathway and the microenvironment in motion.

I hope Pfizer doesn't give up on this therapy.


Jimmy B

Some Thing New I have found Out about Melanoma!!!! .. Jim Breitfeller

Excerpt from:

"Melanoma invasion – current knowledge and future
directions"


Cedric Gaggioli and Erik Sahai*
Tumour Cell Biology Laboratory, Cancer Research UK, London
Research Institute, London, UK
*Address correspondence to E. Sahai,
e-mail: erik.sahai@cancer.org.uk


"This has dramatic implications
for any attempts to translate any in vitro findings
regarding melanoma cell line invasion into the clinical
situation. The mode of invasion affects the sensitivity of
different cell lines to blockade of MMP function; generally
cells invading with a rounded morphology characteristic
of strong cortical acto-myosin contractility are not
sensitive to MMP inhibition because they can use force
mediated matrix remodelling in place of proteolysis
(Wyckoff et al., 2006)."

"However, cells that do not generate
such high levels of force may be more dependent on
MMP function. When this was directly tested using
WM266.4 cells it was observed that the cells actually
converted to a more rounded MMP independent mode
of invasion (Sahai and Marshall, 2003). Friedl and colleagues
have also demonstrated changes in the mode of
tumour cell invasion in response to blockade of either
protease or integrin beta 1 function (Hegerfeldt et al.,
2002; Wolf et al., 2003)."

"These studies strongly suggest that some melanoma cells can switch their mode of invasion in response to different environmental challenges.
The molecular basis of this plasticity is not well
understood, microarray analyses have demonstrated that
metastatic melanoma cells express genes associated
with a diverse range of cell lineages and this may in part
explain the diverse modes of motility that melanoma
cells can exhibit in vitro (Hendrix et al., 2001)."

" Analysis of clinical samples suggest that melanoma can invade
both collectively and as single cells; however, our understanding
of switching between modes of invasion and
the cytoskeletal regulators critical for the different
modes of invasion is still very limited."



Some Melanoma Cells can Adapt to their Environment. This has major implications based on Dr. Sahai findings.

This may be why Melanoma is so hard to treat.


Jimmy B