Effect of hCLCA2 attenuation on cell proliferation and survival. Stable knockdown cell lines were generated by infection with lentiviruses expressing shRNAs (H2sh1; H2sh2; or NC, negative control), followed by puromycin selection. The extent of knockdown was measured by immunoblot (A, inset). To measure proliferation rate, identical numbers of cells were seeded in multiwell plates and counted at one day intervals on a Vi-cell instrument (A). B-C, surviving cell number after treatment with doxorubicin (B, 3 μM for 12h; C, 0.5 μM for 3 days) followed by medium change and recovery for 3 or 20 days.