TLR4 and colorectal adenocarcinoma: Another in vitro study revealed that Nigella sativa-derived melanin inhibited the proliferation of two colorectal adenocarcinoma cell lines (HT-29 and SW620), and exerted a pro-apoptotic effect by activating the intrinsic mitochondria-dependent apoptotic pathway, c-Jun N-terminal kinase (JNK) pathway, and caspase-3/-7, and by inhibiting the expression of B-cell lymphoma 2 (Bcl-2) family proteins, as well as the extracellular signal-regulated kinase (ERK) activity partially via toll-like receptor 4 (TLR4) [53].