Figure 4

From: Par6G suppresses cell proliferation and is targeted by loss-of-function mutations in multiple cancers

Figure 4

Identification of gene deficiencies, which break epithelial cell cycle proliferation. (a) Analysis of proliferative activity in the presence of acute Myc activation and indicated shRNAs. Acinar structures were allowed to form in Matrigel for 15 days to reach quiescence and thereafter Myc was activated for 3 days. The acini containing 1 Ki-67-positive cells were scored as positive. The Ki-67 positivity corresponding to the effect of indicated shRNA without Myc (Myc OFF) was normalized to 1 and the relative values corresponding to the effects of indicated shRNAs with Myc are presented. Dashed line indicates the 1.2-fold change (cutoff limit). (b) Proliferative activity in day-18 acini expressing the indicated shRNAs with or without acute Myc activation. Mean and s.d. are from three independent experiments and P-values by Student’s t-test. (c) Proliferative activity in day-18 acini expressing Myc (+ 4-hydroxytamoxifen (+4-OHT)) with shRNAs targeting either PARD6B or PARD6G. Note that silencing of PARD6G perturbs establishment of epithelial cell cycle restriction (Ki-67 in the absence and presence of Myc), whereas, in contrast, silencing of PARD6B allows cells to enter quiescence (Ki67 negative without Myc) but enables escape from the quiescence with Myc (Ki67 positivity with Myc). Scale bar 20 μm. (d) Comparison of the effects of PARD6B, PARD6G and LKB1 knockdowns on the proliferative activity of acini expressing acutely activated Myc (shPARD6B data are derived from the results presented in graph B). At least 50 acini were counted in each experiment. *P<0.5; **P<0.05; ***P<0.005. NS, not significant.