I am still not sure whether this is going to be a good review or a bad review. It may shake out one way or another as I write it.
We do a lot of signaling as we work on a intracellular signaling scaffold which functions in a lot of different pathways, so I always pay attention to new email from SABiosciences/Qiagen on their new PCR and luciferase arrays. Upon reading about it the Cignal Finder 45-pathway array seemed to provide an awesome way to apply very sensitive luciferase assays to test 45 pathways in a single shot.
It is a 96 well plate with 45 reporters in duplicates and 3 positive and negative controls that you can use to test you drug, siRNA, over expression plasmid on your cell line of choice. The protocol is simple and straightforward: the DNA is in the wells, you add the cells and transfection reagent and the next day you test for luciferase and renilla activity. At $1,600 for a 10 plate pack, plus dual-luciferase assay reagents, it can run around $200-300 per plate, which in triplicates for 2 conditions can be almost $2,000 per experiment. But screening 45-pathways at once could be totally worth it and SABiosciences always run some kind of deal on the plates (and you can use a fraction of the luciferase reagent recommended in the Promega protocol).
We know our protein of interest would really strongly activate NF-kappaB and we have done it with a different reporter, so that was our positive control. The first plate was amazing! There were very clear difference between reporters, the duplicates looked very consistent and a whole bunch of interesting pathways lit up in addition to NF-kappaB in our experimental condition. The dynamic range of response was incredible with some reporters with intensity in the 2,000,000 intensity units and some in the 2,000. And so we embarked in a huge study with over expression and siRNA...and ordered another 10-pack. Qiagen provided us with a handy Excel file for analysis where we just needed to plug the results of luciferase and renilla for each plate and everything would be calculated and plotted for us.
I was intrigued by some of the results and started paying a lot of attention to the intensity measurements, and that is when things started getting ugly. We had noticed that some of the duplicates were asymmetric in intensity when a low intensity reporter was next to a very high intensity one. I had had similar problems in the past with white plates in our luminometer, where we noticed spillover of fluorescence in neighboring wells. Some people say it's the fluorescence passing trough the white walls, others that the detector is far from the plate and the fluorescence spills over from above like a halo. Also instead of looking at the results in the Qiagen spreadsheet where they are in linear format, I analyzed everything in plate format, where I could see which well was above, below, left and right of any particular reporter. That is when half of our hits became uninterpretable because they could simply be due to spillover from the strong hit next door. Qiagen recommended to half the amount of lysate, but that didn't help much as the results were basically identical. So we were stuck with the option of spending $500 per troubleshooting attempt or find some other solution....
They said it must be our luminometer, which is a possibility, but that's the machine we have in the department and their product should work even for older machines. They gave us 2 plates for free for testing, which was nice, but still leaves for $500 per troubleshooting for each one of the other variables (machine, reagents, lysate amount). Right now I am faced with a conundrum: I have some data I believe from the array and some data I do not believe, which I think is due to spillover. I cannot publish the whole array because I would have to explain it is a problematic product and I have requested for a sample of the 6-8 reporters that are iffy, but I was told I had to buy them individually, which I am not inclined to do at this time, since I do not want to waste my grant money to troubleshoot their product for them.
At the same time, their reporters work beautifully and the data we have is very robust, though for us it was more a 30-pathway array than a 45-pathway because of the issues.....I am open to suggestions from other people who may have tried the product and who may have other ideas. Also, I am not entirely satisfied with the way they recommend to analyze the reporters and I'd love input on that also.
We do a lot of signaling as we work on a intracellular signaling scaffold which functions in a lot of different pathways, so I always pay attention to new email from SABiosciences/Qiagen on their new PCR and luciferase arrays. Upon reading about it the Cignal Finder 45-pathway array seemed to provide an awesome way to apply very sensitive luciferase assays to test 45 pathways in a single shot.
It is a 96 well plate with 45 reporters in duplicates and 3 positive and negative controls that you can use to test you drug, siRNA, over expression plasmid on your cell line of choice. The protocol is simple and straightforward: the DNA is in the wells, you add the cells and transfection reagent and the next day you test for luciferase and renilla activity. At $1,600 for a 10 plate pack, plus dual-luciferase assay reagents, it can run around $200-300 per plate, which in triplicates for 2 conditions can be almost $2,000 per experiment. But screening 45-pathways at once could be totally worth it and SABiosciences always run some kind of deal on the plates (and you can use a fraction of the luciferase reagent recommended in the Promega protocol).
We know our protein of interest would really strongly activate NF-kappaB and we have done it with a different reporter, so that was our positive control. The first plate was amazing! There were very clear difference between reporters, the duplicates looked very consistent and a whole bunch of interesting pathways lit up in addition to NF-kappaB in our experimental condition. The dynamic range of response was incredible with some reporters with intensity in the 2,000,000 intensity units and some in the 2,000. And so we embarked in a huge study with over expression and siRNA...and ordered another 10-pack. Qiagen provided us with a handy Excel file for analysis where we just needed to plug the results of luciferase and renilla for each plate and everything would be calculated and plotted for us.
I was intrigued by some of the results and started paying a lot of attention to the intensity measurements, and that is when things started getting ugly. We had noticed that some of the duplicates were asymmetric in intensity when a low intensity reporter was next to a very high intensity one. I had had similar problems in the past with white plates in our luminometer, where we noticed spillover of fluorescence in neighboring wells. Some people say it's the fluorescence passing trough the white walls, others that the detector is far from the plate and the fluorescence spills over from above like a halo. Also instead of looking at the results in the Qiagen spreadsheet where they are in linear format, I analyzed everything in plate format, where I could see which well was above, below, left and right of any particular reporter. That is when half of our hits became uninterpretable because they could simply be due to spillover from the strong hit next door. Qiagen recommended to half the amount of lysate, but that didn't help much as the results were basically identical. So we were stuck with the option of spending $500 per troubleshooting attempt or find some other solution....
They said it must be our luminometer, which is a possibility, but that's the machine we have in the department and their product should work even for older machines. They gave us 2 plates for free for testing, which was nice, but still leaves for $500 per troubleshooting for each one of the other variables (machine, reagents, lysate amount). Right now I am faced with a conundrum: I have some data I believe from the array and some data I do not believe, which I think is due to spillover. I cannot publish the whole array because I would have to explain it is a problematic product and I have requested for a sample of the 6-8 reporters that are iffy, but I was told I had to buy them individually, which I am not inclined to do at this time, since I do not want to waste my grant money to troubleshoot their product for them.
At the same time, their reporters work beautifully and the data we have is very robust, though for us it was more a 30-pathway array than a 45-pathway because of the issues.....I am open to suggestions from other people who may have tried the product and who may have other ideas. Also, I am not entirely satisfied with the way they recommend to analyze the reporters and I'd love input on that also.