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gdpawel · 06-27-2010, 08:21 AM

Cell-based chemoresponse assays test fresh "live" cells in their three dimensional (3D), floating clusters (in their natural state), not passaged cells (cell-lines). Established cell-line is not reflective of the behavior of "fresh" tumor cells in primary culture in the lab, much less in the patient. Solid tumor specimens are cultured in concical polypropylene microwells for 96 hours to increase the proportion of tumor cells, relative to normal cells.

Polypropylene is a slippery material which prevents the attachment of fibroblasts and epithelial cells and encourages the tumor cells to remain in the form of three dimensional (3D), floating clusters. Real life 3D analysis makes chemoresponse assays indicative of what will happen in the body.

One of the problems with genetic tests is in evaluating the data which exists to validate the predictive accuracy of them. Generally, a large number of archival specimens are batch processed together, within a very narrow time frame, by the same research team, so all the technical variables are minimized, which makes it much easier to get good results than in a "real world" setting, where specimens are tested over a period of weeks, months, years, by different people, with different laboratory reagents, as occurs in the "real world."

Evaluating "real world" data, requires specimens that are tested as they are logged into the lab in question, in "real time." No one is publishing "real world" studies, except private laboratories performing cell-based chemoresponse assays, which can only do "real world" studies, because their studies require fresh, viable specimen, which must be accessioned and tested in "real time," under "real world" conditions.

The "cell-death" assays are not growing anything. They are testing a drug or combinations of drugs with cells that are in their natural state (live or fresh). Three dimensional tumor cell clusters. Clusters maintain natural cell-cell interactions. This makes the assays indicative of what will happen in the body. The protocol takes "fresh" patient tumor cells and floats them in newer 3D cell suspensions.

As the researchers at Johns Hopkins and Washington University have found out, our body is 3D, not 2D in form, undoubtedly, this novel step better replicates that of the human body. Traditionally, in-vitro (in lab) cell-lines have been studied in 2 dimensions (2D) which has inherent limitations in applicability to real life 3D in-vivo (in body) states. Recently, other researchers have pointed to the limitations of 2D cell line study and chemotherapy to more correctly reflect the human body.

Literature Citation:
Functional profiling with cell culture-based assays for kinase and anti-angiogenic agents Eur J Clin Invest 37 (suppl. 1):60, 2007
Functional Profiling of Human Tumors in Primary Culture: A Platform for Drug Discovery and Therapy Selection (AACR: Apr 2008-AB-1546)

06-27-2010, 08:21 AM	#4
gdpawel Senior Member Join Date: Aug 2006 Location: Pennsylvania Posts: 1,080	Cells In 3-D Do Reveal Cancer Targets Cell-based chemoresponse assays test fresh "live" cells in their three dimensional (3D), floating clusters (in their natural state), not passaged cells (cell-lines). Established cell-line is not reflective of the behavior of "fresh" tumor cells in primary culture in the lab, much less in the patient. Solid tumor specimens are cultured in concical polypropylene microwells for 96 hours to increase the proportion of tumor cells, relative to normal cells. Polypropylene is a slippery material which prevents the attachment of fibroblasts and epithelial cells and encourages the tumor cells to remain in the form of three dimensional (3D), floating clusters. Real life 3D analysis makes chemoresponse assays indicative of what will happen in the body. One of the problems with genetic tests is in evaluating the data which exists to validate the predictive accuracy of them. Generally, a large number of archival specimens are batch processed together, within a very narrow time frame, by the same research team, so all the technical variables are minimized, which makes it much easier to get good results than in a "real world" setting, where specimens are tested over a period of weeks, months, years, by different people, with different laboratory reagents, as occurs in the "real world." Evaluating "real world" data, requires specimens that are tested as they are logged into the lab in question, in "real time." No one is publishing "real world" studies, except private laboratories performing cell-based chemoresponse assays, which can only do "real world" studies, because their studies require fresh, viable specimen, which must be accessioned and tested in "real time," under "real world" conditions. The "cell-death" assays are not growing anything. They are testing a drug or combinations of drugs with cells that are in their natural state (live or fresh). Three dimensional tumor cell clusters. Clusters maintain natural cell-cell interactions. This makes the assays indicative of what will happen in the body. The protocol takes "fresh" patient tumor cells and floats them in newer 3D cell suspensions. As the researchers at Johns Hopkins and Washington University have found out, our body is 3D, not 2D in form, undoubtedly, this novel step better replicates that of the human body. Traditionally, in-vitro (in lab) cell-lines have been studied in 2 dimensions (2D) which has inherent limitations in applicability to real life 3D in-vivo (in body) states. Recently, other researchers have pointed to the limitations of 2D cell line study and chemotherapy to more correctly reflect the human body. Literature Citation: Functional profiling with cell culture-based assays for kinase and anti-angiogenic agents Eur J Clin Invest 37 (suppl. 1):60, 2007 Functional Profiling of Human Tumors in Primary Culture: A Platform for Drug Discovery and Therapy Selection (AACR: Apr 2008-AB-1546)