Published online Jun 24, 2022. doi: 10.5306/wjco.v13.i6.505
Peer-review started: December 27, 2021
First decision: February 15, 2022
Revised: February 24, 2022
Accepted: April 26, 2022
Article in press: April 26, 2022
Published online: June 24, 2022
Processing time: 176 Days and 21 Hours
Triple negative is the subtype of breast cancer with the worst prognosis, showing an increase in resistance to chemotherapy in smoking patients, who have high levels of nicotine in their blood. In lung cancer, it has been proposed that the activation of nicotinic acetylcholine receptors could be responsible for the modulation of several parameters of tumor biology and the loss of effectiveness of chemotherapeutic treatment, but it is not known what occurs in a nearby organ such as the breast.
Given that breast tumor-bearing patients have a low efficiency to antitumor therapy, knowledge of the signaling pathways involved in this phenomenon is important to generate new therapeutic targets that improve sensitivity to treatment.
This research aimed to determine the signaling pathways involved in the nicotinic modulation of the cytostatic effect of paclitaxel in human triple negative breast cancer cells.
The modulatory effect of nicotine on paclitaxel treatment was assessed by the 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The trypan blue exclusion assay was used to evaluate viable cells in response to different treatments. Protein expression levels were evaluated by Western blot assays and apoptosis was determined using immunofluorescence assays with annexin V and 7AAD.
Nicotine decreased paclitaxel’s inhibition of viability and apoptosis in MDA-MB-231 breast cancer cells. This modulation of viability is mediated by the activation of α7 and α9 nicotinic acetylcholine receptors and protein kinases PKC, Ras, MEK, ERK, p38MAPK and the NF-κB pathway. Cells surviving paclitaxel treatment in the presence of nicotine are less sensitive to another cycle with the chemotherapeutic agent probably due an increase in the protein expression of ATP binding cassette transporter G2.
Nicotine modulates the cytotoxic/apoptotic effects of paclitaxel and knowledge of its signaling pathway mediators could allow the development of better strategies to improve triple negative breast cancer therapy, such as nicotinic acetylcholine receptors blockage together with paclitaxel during chemotherapy administration to smoking patients.
Knowledge of the mediators that participate in the nicotinic modulation of paclitaxel’s effect will allow the development of new antitumor strategies that could be applied not only to other subtypes of mammary tumors, but also to tumors in other organs of smoking patients.