Correlation is not causation, and neither Pearson nor Spearman correlation can give you that, and in particular it cannot give you a direction of the interaction per se. If you are interested in analysis of transcription factors (TF) from RNA-seq data however, you could look into regulatory impact factor (RIF) analysis. We have done RIF analysis, among other things, in a recent paper on our non-model organism. You could try to replicate what we did there if you have enough and suitable measurements.