I am trying a clonogenic assay with PC3 (prostate cancer) cells. Since I am trying to standardize the conditions for the assay first, I am not using any treatment at this point; instead I am trying to observe the colony forming ability of the cells, and testing different conditions like optimal plating density, media, optimal number of days for incubation etc. We maintain these cells in RPMI-1640 with 10% FBS, and 1% each of Penn Strep and Non-essential amino acid. But, I am also testing out one set of conditions where I am adding 15% of human methyl-cellulose base media from R& D biosystems (HSC002). Does anyone here have experience working with this media for clonogenic assay particularly? These cells are adherent, so once the cells adhere, can I change the media? Do you usually recommend a PBS wash in between changing the media? Thank you.