Availability of aldo-keto reductase 1C3 and ATP-binding cassette B1 as therapeutic targets for alleviating paclitaxel resistance in breast cancer MCF7 cells.

Paclitaxel (PTX) is frequently utilized for the chemotherapy of breast cancer, but its continuous treatment provokes hyposensitivity. Here, we established a PTX-resistant variant of human breast cancer MCF7 cells and found that acquiring the chemoresistance elicits a remarkable up-regulation of aldo-keto reductase (AKR) 1C3. MCF7 cell sensitivity to PTX toxicity was increased by pretreatment with AKR1C3 inhibitor and knockdown of this enzyme, and decreased by its overexpression, inferring a crucial role of AKR1C3 in the development of PTX resistance. The PTX-resistant cells were much less sensitive to 4-hydroxy-2-nonenal and acrolein, cytotoxic reactive aldehydes derived from ROS-mediated lipid peroxidation, compared with the parental cells. Additionally, the resistant cells lowered levels of 4-hydroxy-2-nonenal formed during PTX treatment, which was mitigated by pretreating with AKR1C3 inhibitor, suggesting that AKR1C3 procures the chemoresistance through facilitating the metabolism of the cytotoxic aldehyde. The gain of PTX resistance additively promoted the aberrant expression of an ATP-binding cassette (ABC) transporter ABCB1 among the ABC transporter isoforms. The combined treatment with AKR1C3 and ABCB1 inhibitors overcame the PTX resistance and cross-resistance to another taxane-based drug docetaxel. Collectively, combined treatment with AKR1C3 and ABCB1 inhibitors may exert an overcoming effect of PTX resistance in breast cancer.

Effectiveness of distributing pocket cards in improving the behavior, attitude, and knowledge regarding proper medication use among junior high school students in Japan.

Objective: This study aimed to explore the effectiveness of distributing pocket cards with summaries of key information on appropriate medication usage after the implementation of a structured school-based medication education program for junior high school students in Japan. Methods: A total of 227 3rd-grade high school students participated in the intervention. Students who received the program without the provision of pocket cards in 2022 were included in the comparison group, and students who took the program with the provision of pocket cards in 2023 were included in the intervention group. After propensity score matching, the final sample of N = 116 comprised n = 58 comparison group participants and n = 58 intervention group participants. Questionnaires were administered at baseline, end-of-class, and 3-month follow-up to assess the changes in behavior, attitude, and knowledge scores. Results: The matched intervention group showed significantly lower scores at the 3-month follow-up than the matched comparison group. The results of the multiple linear regression analysis showed that for both groups, only the attitude scores were significantly correlated with the behavior scores. In addition, regardless of the baseline scores, the matched intervention group demonstrated smaller or negative changes in scores at the 3-month follow-up. Conclusion: Overall, the results of this study did not support the effectiveness of distributing pocket cards after in-class intervention. However, the usefulness of medication education intervention was confirmed. These results emphasize the need to explore other supplemental teaching tools to further enhance the impact of structured medication education programs.

Significance of aldo-keto reductase 1C3 and ATP-binding cassette transporter B1 in gain of irinotecan resistance in colon cancer cells.

Irinotecan (CPT11) is widely prescribed for treatment of various intractable cancers such as advanced and metastatic colon cancer cells, but its continuous treatment promotes the resistance development. In this study, we established CPT11-resistant variants of three human colon cancer (DLD1, RKO and LoVo) cell lines, and found that gain of the resistance elicited an up-regulation of aldo-keto reductase (AKR) 1C3 in the cells. Additionally, the sensitivity to CPT11 toxicity was decreased and increased by overexpression and knockdown, respectively, of the enzyme. Moreover, the resistant cells suppressed formation of reactive 4-hydroxy-2-nonenal by CPT11 treatment, and the suppressive effect was almost completely abolished by addition of an AKR1C3 inhibitor. These results suggest that up-regulated AKR1C3 contributes to promotion of the chemoresistance by detoxifying the reactive aldehyde. Western blot and real-time polymerase-chain reaction analyses and ATP-binding cassette (ABC) B1-functional assay revealed that, among three ABC transporters, ABCB1 was the most highly up-regulated by development of the CPT11 resistance, inferring a significant contribution of pregnane-X receptor-dependent signaling to the ABCB1 up-regulation. The combined treatment with inhibitors of AKR1C3 and ABCB1 potently sensitized the resistant cells to CPT11 and its active metabolite SN38. Taken together, our results suggest that combination of AKR1C3 and ABCB1 inhibitors is effective as adjuvant therapy to enhance CPT11 sensitivity of intractable colon cancer cells.