Total RNA was isolated from tumours or cells using the
RNeasy plus kit (Qiagen) according to the manufacturer’s instructions. cDNA was synthesized from 1 μg of RNA using the
SuperScript VILO cDNA synthesis kit (Thermo). qPCR was performed in triplicates with 2 μl of diluted cDNA (1:10) using
PerfeCTa SYBR Green FastMix (Thermo) on a Bio-Rad
iCycler RT–PCR detection system. Expression was normalized to
Actb or
Gapdh. All oligonucleotides used in this study are listed in
Supplementary Data Table 4. All qPCR experiments were reproduced using at least three biological replicates.
Alternatively, a Mouse WNT Signaling Pathway RT
2 Profiler PCR Array (Qiagen) was used according to manufacturer’s instructions. Raw expression values were thresholded to drop non-detected and lowly expressed genes (maximum
Ct value set to 33; 0 values set to 33). Array position to gene-name mapping details were retrieved from the manufacturer’s website (
www.pcrdataanalysis.sabiosciences.com). Expression values for all genes per array were normalized to the expression of the housekeeping gene
Gusb. Three replicates of stroma samples and three replicates of tumour samples were compared to calculate log2 fold-change and differential expression significance values (2-sided
t-test).
Tammela T., Sanchez-Rivera F.J., Cetinbas N.M., Wu K., Joshi N.S., Helenius K., Park Y., Azimi R., Kerper N.R., Wesselhoeft R.A., Gu X., Schmidt L., Cornwall-Brady M., Yilmaz Ö.H., Xue W., Katajisto P., Bhutkar A, & Jacks T. (2017). A Wnt-producing niche drives proliferative potential and progression in lung adenocarcinoma. Nature, 545(7654), 355-359.