Does trypsin with with phenol harm MCF7 cells?

We experience from time to time that in cultured wild boar lung cells foci appear 1-2 days after propagation in which cells are apparently dead (circle in left picture). One day later, nearly the entire culture is affected (right picture). Trypsinization of these cells results in normal cell cultures in which this effect may sometimes appear for one or two further passages  but then the effect disappears. Although the cells appear infected, virus or bacteria are not involved.Transfer of affected cells to nonaffected cells does not lead to spread. In the lab we call this effct Lemming effect because we feel that individual cells are triggered to die and then ask their neighbours to join them. Would be very happy if someone could explain what happens and may perhaps have a solution.

Best,

Günther

We plated cells from nasal brushes on fibroblast. We are now trying to do single cell sequencing on these cells. We have used trypsin EDTA, filters, etc and they still seem to clump and we can not run single cell. Any recommendations please.

the question is technical, for example using cell scraper or trypsinization...etc.

I've been working on MCF7 cell lines for nearly 7 months now. Today while checking one of the flasks, I found its media color dark green and all cells floating dead.

I've trypsinized this flask 3 days ago and transferred the cells to a new T25 flask. I changed the media the following day and the cells were super healthy and fine (40% confluent). Today, I was about to change the media but I found its color dark greenish.

I wonder what might be the cause this to avoid it in the future.

P.S. Water bath and incubator were cleaned 5 days before the incident. Media has penstrip (1x). No obvious micro-organisms were noted under the microscope.

I am checking the mRNA expression of estrogen receptor along with other genes following estrogen treatment in MCF-7 cells. But I am treating cells with 100nM E2. Is it a very high concentration for 1 x 106 cell density? Also I am culturing MCF-7 cells in phenol containing media first and after 24h, changing the media to phenol red free media  + 5% charcoal stripped FBS for 6h followed by treatment with E2. Am I doing appropriately? So far I am not able to see a significant change in the mRNA expression of ESR and other genes as well as no change in proliferation rate when compared to untreated cells. Please suggest. Thanks.

I am confused about this, and maybe is a silly question, but...

In the lab I am working they store the freezing media at 4 C degrees. The freezing media contains 5% DMSO + 95% FBS. It is right to store at 4 C degrees, or is better at -20 C degrees? I made a new freezing media last week, following the same protocol they used (I only have one year in the lab). Should I keep the freezing media at 4C degrees or store it at -20 C degrees?

I am culturing Human Aortic Endothelial Cells from ThermoFisher (Cat #: C0065C). I am doing it with the media and supplements they sell for it, which are called M200 and LVES respectively. Despite the version of the media I am using containing phenol red, I have never seen cell media change color. Although they do not change color, I very often observe round, refractive particles that look really similar to cells when I add trypsin to them which leads me to believe these particles are unattached cells. I am guessing these unattached cells are dead cells, but I am not sure why they are dying. If the media was exhausted, there would be a shift in pH and thus in color, right? If there was not meant to be any shift in color with these cells I do not see why the company would sell a version of this media with phenol red in it.

I have been testing different times to change media, but it seems to fluctuate. Sometimes they will last three days and still be fine, but sometimes I see those refractive particles just two days after I have changed media.

Any suggestions? Perhaps this is normal and nothing to worry about.