Whole Cell Profiling

  1. Researchers have seen that whether a tumor was a breast tumor, prostate tumor, lung tumor or colon tumor, it didn't correlate to how the cancers interacted with standard anticancer drugs. Their findings suggest that traditional cancer treatments, which have established different drug regimens for lung, prostate or ovarian cancer, for example, should be replaced with therapies that use drugs deemed to be of highest benefit based on the tumor's pharmacologic profile. Treatment choice would be determined by how each patient's tumor reacts to anticancer drugs, regardless of the tumor's anatomical origin.

    The drug effect is independent of where the tumor came from in the body. Under current treatment selection methods virtually no chemotherapeutic drug has been successful in more than 50 percent of patients with advanced cancer. But instead of considering a drug that works only ten percent of the time a failure, it would be better to consider such a drug effective for one in ten tumors and to search for the agents among the current arsenal of chemotherapeutic drugs that will work for the rest. Having a good tumor-drug match not only would improve survival rates, it would be cost-effective, and the high cost of the newer cancer therapies reinforces the necessity of choosing the right therapy the first time around.

    The introduction of new "targeted" drugs has not been accompanied by specific predictive tests allowing for a rational and economical use of the drugs. Given the technical and conceptual advantages of Cell Culture Assays together with their performance and the modest efficicay of therapy prediction on analysis of genome expression, there is reason for a renewal in the interest for these for optimized use of medical treatment of malignant disease.

    Clinical study results published at the annual meeting of the American Society of Clinical Oncology (ASCO) show that a new laboratory test, called EGFRx, has accurately identified patients who would benefit from treatment with the molecularly-targeted anti-cancer therapies. The finding is important because the EGFRx test, which can also be applied to many emerging targeted cancer drugs, could help solve the growing problem of knowing which patients should receive costly, new treatments that can have harmful side-effects and which work for some but not all cancer patients who receive them. The test can discriminate between the activity of different targeted drugs and identify situations in which it is advantageous to combine the targeted drugs with other types of cancer drugs.

    The new test relies upon what is called "Functional Profiling" in which living tumor cells are removed from an individual cancer patient and exposed in the laboratory to the new drugs. A variety of metabolic and apoptotic measurements are then used to determine if a specific drug was successful at killing the patient's cancer cells. The whole cell profiling method differs from other tests in that it assesses the activity of a drug upon combined effect of all cellular processes, using combined metabolic and morphologic endpoints. Other tests, such as those which identify DNA or RNA sequences or expression of individual proteins often examine only one component of a much larger, interactive process.

    The whole cell profiling method makes the statistically significant association between prospectively reported test results and patient survival. Using the EGFRx Assay and the "functional profiling" method, can correlate test results which are obtained in the lab and reported to physicians prior to patient treatment, with significantly longer or shorter overall patient survival depending upon whether the drug was found to be effective or ineffective at killing the patient's tumor cells in the laboratory.

    Over the past few years, researchers have put enormous efforts into genetic profiling as a way of predicting patient response to targeted therapies. However, no gene-based test has been described that can discriminate differing levels of anti-tumor activity occurring among different targeted therapy drugs. Nor can an available gene-based test identify situations in which it is advantageous to combine a targeted drug with other types of cancer drugs. So far, only whole cell profiling has demonstrated this critical ability.

    Not only is this an important predictive test that is available "today," but it is also a unique tool that can help to identify newer and better drugs, evaluate promising drug combinations, and serve as a "gold standard" correlative model with which to develop new DNA, RNA, and protein-based tests that better predict for drug activity.

    These "targeting" drugs are expensive, costing patients and insurance carriers $5,000 to $7,000 or more per month of treatment. Patients, physicians, insurance carriers, and the FDA are all calling for the discovery of predictive tests that allow for rational and cost-effective use of these drugs.

    The whole cell profiling approach, holds the key to solving some of the problems confronting a healthcare system that is seeking ways to best allocate available resources while accomplishing the critical task of matching individual patients with the treatments most likely to benefit them.

    Genomic testing is not the answer, without cell culture analysis. In developing a program to discover gene expression microarrays, which predict for responsiveness to drug therapy, the way to identify informative gene expression patterns is to have a gold standard and that cell culture assays are by far the most powerful, efficient, useful gold standard to have.

    The assay is the only assay that involves direct visualization of the cancer cells at endpoint. This allows for accurate assessment of drug activity, discriminates tumor from non-tumor cells, and provides a permanent archival record, which improves quality, serves as control, and assesses dose response in vitro (includes newly-emergent drug combinations).


    Last edit by gdpawel on Nov 12, '07 : Reason: update
  2. 2 Comments

  3. by   gdpawel
    Research has shown that controlling production of new blood vessels can restrict tumor growth, often prolonging the life of the cancer patient. Perhaps the most widely-used anti-angiogenic agent to emerge to date is a drug called Avastin. Avastin was approved by the FDA for use in combination with intravenous 5-fluorouracil-based chemotherapy for first-line treatment of patients with metastatic colorectal cancer. However, Avastin has also shown activity in many other solid tumor types such as breast, lung, and ovarian cancers. As with most targeted-therapy drugs, Avastin does not necessarily benefit every patient and it is expensive. Further, no test currently exists that shows reliably who will benefit from it.

    The Weisenthal Cancer Group has developed an assay for microvasacular viability (M.V.V.) to identify potential responders to Avastin, Nexavar, Sutent, and other anti-angiogenic drugs and to assess previously unanticipated direct and potentiating anti-angiogenic effects of targeted therapy drugs such as Tarceva and Iressa. Prior to development of the M.V.V. assay it was thought that the lack of an intact tumor micro-vasculature would prevent in vitro drug studies in disaggregated tissues. However, it was discovered that endothelial cells are present in tumor microclusters and it appears that drug effect upon these cells can be assessed in the M.V.V. assay.

    The M.V.V. assay is being offered currently to selected Weisenthal Cancer Group clients on a research basis and as an adjunct to either a Weisenthal Cancer Group standard CytoRxTM assay or an EGFRx tyrosine kinase assay.


    Last edit by gdpawel on Nov 12, '07 : Reason: update
  4. by   globalRN
    Quote from gdpawel
    While some types of cancer remain localized for many years and never spread to other organs, others are systemic disease at the time the patient first became aware of the primary tumor. Localized tumors can be dealt with by surgeons with successful (curative) results. However, tumors which have spread (metastasized) to other organs are virtually impossible to remove and will eventually kill the patient unless they respond to systemic treatment (chemotherapy), which is designed to kill tumor cells.

    Cancer occurs when cells lose the molecular mechanisms that control their growth and death, resulting in uncontolled cell proliferation and form tumors. These molecular mechanisms are contolled by genes encoded in the DNA of the cell, and acquired mutations or other changes in these genes lead to loss of control. Therefore, cancers are genetic diseases. But, each individual tumor, even those of the same general type will have different mutations, the consequences of which may be altered by the tissue environment, which can in turn be influenced by the external environment. The result is that cancers are even more different from each other than the individuals affected.

    This heterogeneity means that a particular drug will rarely be effective against all tumors of a particular type, and the degree of efficacy will vary between patients. Also, as a result of their original mutations, many tumor cells acquire the ability to adapt rapidly to changes in their environment, sometimes by further mutation, often by molecular changes which induce resistance to the drugs used to treat them. Further courses of chemotherapy then select for resistant cells, and the treatment eventually fails to control the tumor.

    To overcome the problems of heterogeneity and prevent rapid cellular adaptation, oncologists are able to tailor chemotherapy to individual patients. This is done by testing the tumor cells to see if they are susceptible to particular drugs, before giving them to the patient.

    Many hope that molecular tests may hold the key to success, particularly as more specific drugs are designed to hit the molecular changes that are responsible for the uncontrolled growth of cancer cells. Like testing breast cancer for the presence of hormone receptors and over-expression of growth factor receptors. However, most drugs cannot be looked at in this way and tests that are now in use have limited predictive accuracy of around 65%.

    So how about exposing cancer cells to the drug and testing their effect? You need to expose the cancer cells to the drugs without altering their behavior from the original tumor. It is not possible to remove the non-cancer cells from the tumor without doing this. But certain assay culture methods can get rid of the non-cancer cells before the end of the culture period.

    These cell culture assays have contributed to the molecular understanding of chemosensitivity and resistance.

    An international study published in the August 5, 2004 issue of the New England Journal of Medicine reported that cell culture assay tests with a cell-death endpoint are effective in identifying gene expression patterns that correlate with clinical drug resistance. The study, titled "Gene Expression Patterns in Drug Resistant Acute Lymphoblastic Leukemia Cells and Response to Treatment" employed the cell-death assay to examine drug resistance at the molecular level.

    The investigators exposed cells to drugs and cultured in a 96 hour suspension cell culture drug resistance assay (MTT) to define sensitivity and resistance. They used the data to define gene expression patterns associated with sensitivity and resistance to each of 4 drugs commonly used in the treatment of childhood leukemia. They were able to show that the gene expression definitions of sensitivity and resistance were significantly and independently associated with treatment outcome.

    This work could not have been done without prior work in more than a thousand cell culture drug resistance test assays from children with leukemia to define sensitivity and resistance for each of the four drugs. Cell culture assays are the Rosetta Stone which allows for identification of clinically relevant gene expression patterns which correlate with clinical drug resistance for different drugs in specific diseases.

    In an accompanying editorial, a review of the study findings indicated that the observed gene expression profiles represent fundamental biochemical features and suggests that gene expression profiles could be used to alter therapy instead of in vitro sensitivity testing. They go on to state that there is no single gene whose expression accurately predicts therapy outcome, emphasizing that cancer is a complex disease and needs to be attacked on many fronts.

    A number of cell culture assay labs across the country have data from tens of thousands of fresh human tumor specimens, representing virtually all types of human solid and hematologic neoplasms, in which were tested a median of 17 drugs and/or drug combinations under very similar conditions to that of this acute lymphoblastic leukemia study. Cells were exposed to drugs and cultured in suspension for 96 hours and tested simultaneously with two different assays (MTT and DISC). What this means is that these cell culture assay labs have the Rosetta Stone database necessary to define sensitivity and resistance for virtually all of the currently available drugs in virtually all types of human solid and hematologic neoplasms.

    Improving cancer patient diagnosis and treatment through a combination of cellular and gene-based testing will offer predictive insight into the nature of an individual's particular cancer and enable oncologists to prescribe treatment more in keeping with the heterogeneity of the disease. The biologies are very different and the response to given drugs is very different.
    I think it is very exciting....can tailor the tx to the patient

    -no need to waste your time on tx that wouldn't help you....can spend that
    time doing other more important things...enjoying what time you have left

    - oncologist can more correctly predict which therapy would give you the
    most likelihood of a response/cure