RESUMO
Paclitaxel has been used widely to treat breast cancer and other types of cancer. However, resistance is a major cause of failure for treatment and results in cancer progression. The present study investigated the association between paclitaxel resistance and the mesenchymal phenotype, using a model of primary breast cancer cells and employing four different cultures, two with an epithelial phenotype (MBCDF and MBCD17) and two with a mesenchymal phenotype (MBCDF-D5 and MBCD3). Epithelial-mesenchymal markers were evaluated by western blotting; MBCDF and MBCD17 cells expressed E-cadherin, SNAIL, Slug, and Twist, low levels of N-cadherin, but not vimentin. MBCDF-D5 and MBCD3 cells expressed N-cadherin, vimentin, and higher levels of SNAIL, and low levels of E-cadherin, Slug, and Twist. Cell viability was evaluated using a crystal violet assay after paclitaxel treatment; primary breast cancer cells with mesenchymal phenotype were resistant to paclitaxel compared with the epithelial primary breast cancer cells. Furthermore, using western blotting, it was revealed that mesenchymal cells had elevated levels of nuclear factor-κΒ (NF-κB) p65 and IκB kinase (IKK). Additionally, it was demonstrated that paclitaxel-induced degradation of the inhibitor of NF-κB, activation of NF-κB in a dose-dependent manner, and Bcl-2 and Bcl-xL upregulation. Finally, employing western blotting and crystal violet assays, the effects of the proteasome inhibitor ALLN were assessed. ALLN inhibited paclitaxel-induced NF-κB activation and restored the sensitivity to paclitaxel. Together, these data suggest that targeting the NF-κB/IKK axis might be a promising strategy to overcome paclitaxel resistance.
RESUMO
BACKGROUND: Immunotherapy has demonstrated an improved overall survival (OS) and progression-free survival (PFS) as second-line treatment and subsequent lines compared with chemotherapy. MATERIALS & METHODS: This was a retrospective review among eight medical centers comprising 100 patients with a confirmed diagnosis of non-small-cell lung carcinoma, in their second-line treatment or beyond with immune checkpoints inhibitors treatment. The current study aimed to analyze effectiveness of immunotherapy in second-line treatment or further in the Mexican population, using PFS rate, OS rate and the best objective response to treatment by RECIST 1.1 as a surrogate of effectiveness. RESULTS: In total, 100 patients met the criteria for enrollment in the current study. From the total study population, 49 patients (49.0%) were male and 51 (51.0%) were female, with an average age of 60 years and stage IV as the most prevalent clinical stage at the beginning of the study. A total of 61 patients (61.0%) had partial response; 11 (11.0%) stable disease; 2 (2.0%), complete response, 4 (4.0%), progression; and 22 (22.0%) were nonevaluable. We found a median PFS of 4 months (95% CI: 3.2-4.7 months) and an OS of 9 months (95% CI: 7.2-10.7 months). CONCLUSION: The response to immunotherapy is similar, with an improvement in OS and PFS, independent of which drug is used. Patients using nivolumab had a better survival, although that was not statistically significant.
