An enzyme called tryptophan 2,3-dioxygenase or (TDO) enables tumors to avoid detection and rejection by the immune system..Melanoma .Jim Breitfeller

An enzyme called tryptophan 2,3-dioxygenase or (TDO) enables tumors to avoid detection and rejection by the immune system





NEW YORK, NY, May 3, 2012 – The Ludwig Institute for Cancer Research (LICR) announced today the launch of a private biotechnology enterprise, iTeos Therapeutics SA, to develop a novel pre-clinical pipeline of immunomodulators to stimulate the immune system's ability to attack cancer


iTeos co-founder and CEO Michel Detheux, Ph.D. "We now know that combination treatments are likely to be more effective than single therapies in controlling and eventually eliminating cancer. iTeos will pursue this approach by combining existing vaccines with new immunodulatory compounds based on research that has just emerged from the Ludwig Institute."

Cancer immunotherapy

— leveraging the body’s own immune system to attack and destroy tumors — is emerging as a promising method for cancer treatment. Clinical testing of several immunotherapeutic approaches has shown variable success. Tumors often develop survival mechanisms to prevent the attack from the immune system. Researchers are now looking to evaluate the mechanisms that enable these tumors to escape detection by the immune system.

Previously, Brussels scientists from LICR and the de Duve Institute at the Université catholique de Louvain (UCL) studied one enzyme that proved to do just that. It is known as indoleamine 2,3 dioxygenase or IDO1 for short. IDO1 is expressed in many cancers, including prostate, colon, pancreas and cervical tumors. IDO1 blocks the immune system’s ability to reject those tumors, by depriving immune cells of tryptophan. Tryptophan is one of the essential amino acids for the body.

Tryptophan is an amino acid needed for normal growth in infants and for nitrogen balance in adults. It is an essential amino acid, which means your body cannot produce it -- you must get it from your diet.

Tryptophan can be found in:

• Cheese
•Chicken
• Eggs
• Fish
• Milk
• Nuts
• Peanut butter
• Peanuts
• Pumpkin seeds
• Sesame seeds
• Soy
• Tofu
• Turkey
Scientists from the Ludwig Institute for Cancer Research (LICR) in Brussels identified a new target for cancer therapy, an enzyme which prevents the immune system from recognizing and destroying certain types of tumors. Called tryptophan 2,3-dioxygenase or TDO, the enzyme works by depriving immune cells of tryptophan, an amino acid essential to their activity. TDO is produced by a significant number of human tumors including melanomas.

The Ludwig Institute is now applying this knowledge and now is investigating inhibitors of these two enzymes (IDO and TDO).

“Little is known about the TDO enzyme and its ability to trick the immune system and prevent it from destroying deadly tumors” said study lead investigator, Benoit J. Van den Eynde, M.D., Ph.D., Brussels Branch Director at LICR.

The (Belgium) team of scientists then developed an active compound to inhibit TDO enzymatic activity. “Our study showed quite beautifully that the TDO inhibitor restored the ability of mice to reject tumors despite the presence of TDO in tumor cells,” said Dr. Van den Eynde

Cancer research is like analyzing an onion; you pull one layer off at a time and discover another layer of suppression from the tumor’s microenvironment. We are forever gaining knowledge about the immune system. The CURE will come from 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 Devil is in the Details.. All in the Timing and concentration of the Interluekin-2..Melanoma ..Jim Breitfeller

The Devil is in the Details.. All in the Timing and concentration of the Interluekin-2

This short paper is dedicated to all the Melanoma Patients that didnot get a complete response with IL-2 Therapy.

“Administration of (IL-2) Interluekin-2 during the initial phase of the response, clonal expansion and development of the effector function had no effect on the number of (CTL) Cytotoxic T Lymphocytes generated or control of tumor growth. In contrast, a short two day times course of low dose IL-2 at the peak of clonal expansion or at later times resulted in prolonged and expanded responses by the OT-1 CTL, with concomitant decrease in tumor load (Shrinkage) and extension of Survival.”1

An antigen (Ag) recognition event is not predetermined. T-cells that are stimulated by self Ag generally fails to proliferate effectively and undergo induced Apoptosis (programmed cell death) or develop clonal anergy (lack of energy leading to inactivity).

T-cells that are activated with non-self Antigen (Tumor specific antigen) undergo robust clonal expansion that leads to a large generation of effector T-cells, clearance of the foreign antigen-tumors, as well as development of memory cells.

A new cell growth model: IL-2 T-cell system has been postulated by K A Smith and colleagues. In their model, they show that three factors are critical for T-cell cycle progression.

1. Interleukin-2 concentration
2. Interleukin-2 receptor density on the T-cells
3. The duration of the interleukin-2 receptor interaction

Since we only have somewhat of control over Interleukin-2 concentration, the rest of the paper will focus on IL-2 concentration.

By limiting the exogenous IL-2 at the initial response phase, the T-cells in particular, the CD4 + and the CD8 + T-cells have to compete for the IL-2 that is secreted from the cells after activation. It is generally accepted that the T-cells must secrete IL-2 to aid in the expansion and survival of the T-cells. With this clonal expansion of the CD4 + T-cells also generates more subsets including the T-Regulatory foxp3 (CD4+ CD25+ FoxP3).
Tregs cells are notorious for suppressing an immune response. The Tregs cells make up
only 2-5 percent of the overall population of the CD4 + T-cells.

It has been shown that a 4-6 hour window of time was enough time to program the CD4 + T-cells to proliferate even after the separation of the antigen bearing presentation cell (APC). This activation time reflects the time needed to up-regulate the high affinity IL-2 receptor and secrete IL-2, thus facilitation of the IL-2 dependent expanding CD4 + T-cells.

It has been indicated Mueller et al that sustained (TCR) T-cell receptor and CD28 signaling is necessary to maintain an optimal rate of cell division in the presents of IL-2.
Once the antigen is cleared (used up) the CD4 + T-cells stop proliferating. So if you don’t have enough tumor specific antigens that are shed from the tumor, the expansion halts.
In a paper entitled “IL-2 Regulates Expansion of the CD4 + T-cell population by affecting Cell death, Ganusov and colleagues reported that the Il-2 has the most profound effect on the death rate of dividing CD4 + T-cells, specifically that the death rate increases with division number. Division number is the number of times the cells divide.

At the lowest IL-2 concentration, the CD4 + T-cells have the highest death rate over the divisions. They reported at the first cell division they encountered 20% of the cells dying. At the sixth division, the death rate increased to 90 %.





With the T-cells competing for IL-2, the consumption of the Interluekin-2 by the dividing CD4 + T-cells may cause the overall concentration in ones body to decrease causing a premature death to the T-cells. Without CD4 + helper cells, the CD8 + T-cells won’t get cross primed and activated. These CD4+ cells, called helper T cells, bind to antigen presented by B cells. The result is the development of clones of plasma cells secreting antibodies against the antigenic material.

As you can see it is a delicate balancing act. It is like the three bears, you need it just right. To little IL-2 will induce cell death and to much can cause a change in the feedback response loop causing the Tregs to undergo robust clonal expansion shutting down any chance of an immune response.

By increasing IL-2 concentration at the maximum propagation of the CD8+ T-cells, you actually extend the survival and the effector function of the CD8+ T-cells to mature into
Cytoxic T. Lymphocytes (CTLs).

The Interluekin-2 plays another role in this Melanoma Maze. In a study by Janas et al, IL-2 increases the expressions of the perforin and granzyme A, B and C genes in the CD8+ T-cells. This increase expression causes the CD8+ T-cells to mature into Cytoxic T Lymphocytes (CTLs). The exogenous IL-2 is required for the granzyme proteins. As stated previously, CTLs have cytoplasmic granules that contain the proteins perforin and granzymes. 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. Once in the tumor cell, these enzymes are able to breakup (lyse) the cell and destroy it. This is the beginning of the end for the cancer cells.


Conclusion:
The devil is in the details!!!
Interluekin-2 concentration and timing of the addition of the exogenous IL-2 has a critical role to play in The Orchestration of an Inmmune Response.

Lastly, I am going to leave you with my graphical representation of my therapy that has save my life. Study it. I willing to bet that this graph is medical history in the making base on the science research that I did.






Reference

1. Opposing Effects of IL-2 in Tumor Immunotherapy: Promoting CD8 T Cell Growth and Inducing Apoptosis1
Protul Shrikant2 and Matthew F. Mescher3
Center for Immunology, Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455 The Journal of Immunology, 2002, 169: 1753-1759.
http://www.jimmunol.org/cgi/content/full/169/4/1753


Take Care,

Jimmy B

“CD4+ T-regulatory cells: toward therapy for human diseases”Melanoma ..Jim Breitfeller

“CD4+ T-regulatory cells: toward therapy for human diseases”

Thanks to Dr. Megan Levings for taking time out of her busy schedule to email me her research paper on Tregs cells. In my research, I have come to the conclusion that that major barrier to initiating an immune response is over coming the Treg suppression. Remember I said “BLAME IT ON THE TREGS”, well most of the research finding are supporting this piece of the Melanoma Puzzle.

“T-regulatory cells (Tregs) have a fundamental role in the establishment and maintenance of peripheral tolerance. There is now compelling evidence that deficits in the numbers and/or function of different types of Tregs can lead to autoimmunity, allergy, and graft
rejection, whereas an over-abundance of Tregs can inhibit anti-tumor and anti-pathogen immunity.”

“Several different types of Tregs exist in humans, including specialized subsets of CD4+, CD8+, double negative CD3+ CD4-CD8-, alpha /gamma T cells, and natural killer T (NKT) cells. While it is likely that these different types of Tregs work together in a network to maintain immune homeostasis, the majority of current research is focused on defining the normal function of CD4+ Tregs, because these cells mediate dominant, long-lasting, and transferable tolerance in experimental models.”

Levings and colleagues want to harness the Tregs to develop adoptive cellular therapy protocols that would be used in autoimmunity and inflammation. So they wanted to grow the population of Tregs. We on the other hand want to deplete/suppress them, to push the balance towards an immune response.

The Tregs constitute only 1-2 % of the peripheral CD4+ T cells in humans, but is enough to keep the immune system in check. In in-vitro culture conditions, they can expand rapidly when stimulated with an antigen. If you throw Il-2 into the mix, It can increase the cell population by 5-6 fold. This means that the Treg population when activated and Il-2 is secreted or added like (HD IL-2), is now at 10 to 12 % of the population. This can quickly shut down the immune response. So the Takeaway is that one must plan when to introduce the Il-2 to the therapy. So Lets follow nature. Il-2 Is secreted after the CD4+ T cells are activated. THIS MEANS TIMING OF THE IL-2 IS CRUCIAL TO GENERATING A RESPONSE. How Long do we want to hold off before inoculation of the IL-2? We need the growth profiles of each of the CD4+ T cells.

Based on the data gather by Itoh and Colleagues we want to add the Il-2 at the Maximum propagation of the CD8+ T cells. I t has been reported that when the CD8+ T-cells are grown in the presence of Il-2 , they develop in to (CTL) Cytotoxic T Lymphocytes. That is just what we wanted.

This is where Itoh and Colleagues come in:

In 1988, a paper was published “Autologous Tumor Specific Cytotoxic Lymphocytes in the Infiltrate of Human Metastatic Melanomas Activation by Interleukin 2 and Autologous Tumor Cells, and Involvement of the T Cell Receptor “ by Itoh and Colleagues. In their studies, they propagated (TILs) Tumor infiltrate lymphocytes cells from 12 Metastatic Melanoma patients. They preformed kinetic growth studies in IL-2 and even broke it down three Surface markers (CD3, CD4 and CD8).

The results are as follows:
The Total average maximum propagation was 43 days. (N=12)
The average maximum propagation for (lung, Axilla) was 40 days (n=3)

The average maximum propagation for (CD3) was 78 +/- 11 days (n=12)

The average maximum propagation for (CD4) was 33 +/- 10 days (n=12)
The average maximum propagation for CD4 (lung, Axilla) was 26 days (n=3)

The average maximum propagation for (CD8) was 49 +/- 17 days (n=12)
The average maximum propagation for CD8 (lung, Axilla) was 57 days (n=3)

Base on the above data, it would take about 49 days for my activated CD8+ T cells to reach maximum propagation. Then add the IL-2.

The Orchestration of an Inmmune Response Unrehearsed

Source: All Quotes are excerpts from Dr. Megan Levings’s Paper

So now if you put a clinical trial together and follow the timelines,

So now lets see My actual timeline.


They Always said Timing is Everything!!!!!


Take Care,

Jimmy B

A Vaccine Offers Instant Immunity!!! Melanoma Jim Breitfeller

Technolony Published by MIT Review
Tuesday, March 03, 2009

A new approach primes antibodies to instantly attack cancers, HIV, and other diseases.

By Jennifer Chu

"Now researchers at the Scripps Research Institute have developed preprogrammed chemicals that bind to antibodies and tell them how to recognize part of a pathogen, known as its epitope. In experiments, the team found that such chemicals prompted a therapeutic immune response that inhibited the growth of two types of tumors in mice. The researchers published their findings in the latest issue of the Proceedings of the National Academies of Science."

"We used a chemistry-based approach that wouldn't induce antibodies that might be wasted," says Carlos Barbas, a professor of molecular biology and lead investigator on the paper. "[This approach] could focus an immune response on functional epitopes of the pathogen, be it cancer or a virus."

"Howard Kaufman, director of the Mount Sinai Melanoma and Sarcoma Program, studies cancer's immunosuppressive mechanisms, particularly in melanoma, and is beginning phase I clinical trials to test a melanoma vaccine. Kaufman says that Barbas's vaccine technique represents a new way to treat cancer and other diseases. "It's appealing as an approach," says Kaufman. "It's a way to get instant immunization as opposed to waiting for kinetics to develop T cell responses."


Source:http://www.technologyreview.com/biomedicine/22243/
A Vaccine Offers Instant Immunity






Take Care

Jimmy B

Dr. Polly Matzinger Danger!! Danger!! Melanoma..Jim Breitfeller

Danger signals
"In a 1994 article entitled "Tolerance, Danger and the Extended Family", Matzinger went several steps further by laying out the idea that antigen-presenting cells respond to "danger signals" - most notably from cells undergoing injury, or stress or "bad cell death" (as opposed to apoptosis, controlled cell death). The alarm signals released by these cells let the immune system know that there is a problem requiring an immune response. She argued that T-cells and the immune response they orchestrate occurs not because of a neonatal definition of "self", as in the previous model, nor because of ancient definitions of pathogens, as in Janeway's argument, but due to a dynamic and constantly-updated response to danger as defined by cellular damage."


The Danger Model

The self-non-self model, the predominant model in immunology since the 1950s, began to encounter problems in the late 1980s when immunologists began to recognize that T-cells depend on other cells to pick up and then present the things to which they will respond — and that the T-cell response depends on whether the other cell (known as antigen-presenting cells) is sending activation signals to the T-cells.

In 1989, drawing on the ideas of Thomas Kuhn, Charles Janeway proposed that the old immunological paradigm had reached the limits of its usefulness--or, as he described it, the asymptote of the increase in knowledge which it had brought. Janeway argued that the innate immune system was the real gatekeeper of whether the immune system responded or did not respond. He also argued that the innate immune system used ancient pattern-recognition receptors to make these decisions - recognizing a pathogen by its unchanging characteristics.

Source:Wikipedia

Part of my Research

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