Embelin Enhances the Sensitivity of Renal Cancer Cells to Axitinib by Inhibiting HIF Signaling Pathway.

BACKGROUND: Renal cell carcinoma (RCC) is a common malignant tumor of the urinary system with a high recurrence rate and easy metastasis. Current clinical drugs for renal cell carcinoma include immunotherapies and targeted drugs. Axitinib is a clinically targeted drug for treating renal cell carcinoma, which has shortcomings such as unstable efficacy and easy drug resistance. Therefore, this study aims to determine whether embelin can enhance the sensitivity of renal cancer cells to axitinib and explore its regulatory pathways. METHODS: The enhancing effect of embelin on axitinib was detected using MTT, crystal violet staining, and annexin VFITC staining in two renal cancer cell lines. Western blot was performed to detect the expression of autophagy-related proteins under different conditions. Bioinformatic tools were used to predict the pathways through which embelin may act on renal cancer cells, and pharmacological methods were used to verify the results. RESULTS: Embelin enhanced the sensitivity of renal cancer cells to axitinib in the following aspects: enhancing the inhibition of cell proliferation by axitinib, and the induction of cell apoptosis. HIF was a potential pathway for embelin's action. After IOX2 regulated the HIF-1α pathway, the enhancing effect of embelin on axitinib was weakened. Moreover, after PT2977 regulated the HIF-2α pathway, the enhancing effect of embelin on axitinib was weakened. CONCLUSIONS: Embelin enhanced the sensitivity of A498 and 786-O renal cancer cells to axitinib by inhibiting the HIF pathway.

The A756T Mutation of the ERG11 Gene Associated With Resistance to Itraconazole in Candida Krusei Isolated From Mycotic Mastitis of Cows.

Candida krusei (C. krusei) has been recently recognized as an important pathogen involved in mycotic mastitis of cows. The phenotypic and molecular characteristics of 15 C. krusei clinical isolates collected from cows with clinical mastitis in three herds of Yinchuan, Ningxia, were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry. In addition to sequencing analysis, the ERG11 gene that encodes 14α-demethylases, the expression of the ERG11 gene, and efflux transporters ABC1 and ABC2 in itraconazole-susceptible (S), itraconazole-susceptible dose dependent (SDD), and itraconazole-resistant (R) C. krusei isolates was also quantified by a quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) assay. Sequencing analysis revealed three synonymous codon substitutions of the ERG11 gene including T939C, A756T, and T642C in these C. krusei clinical isolates. Among them, T642C and T939C mutations were detected in itraconazole-resistant and -susceptible C. krusei isolates, but the A756T substitution was found only in itraconazole-resistant isolates. Importantly, the expression of the ERG11 gene in itraconazole-resistant isolates was significantly higher compared with itraconazole-SDD and itraconazole-susceptible isolates (p = 0.052 and p = 0.012, respectively), as determined by the qRT-PCR assay. Interestingly, the expression of the ABC2 gene was also significantly higher in itraconazole-resistant isolates relative to the itraconazole-SDD and itraconazole-susceptible strains. Notably, the expression of ERG11 was positively associated with resistance to itraconazole (p = 0.4177 in SDD compared with S, p = 0.0107 in SDD with R, and p = 0.0035 in S with R, respectively). These data demonstrated that mutations of the ERG11 gene were involved in drug resistance in C. krusei. The A756T synonymous codon substitution of the ERG11 gene was correlated with an increased expression of drug-resistant genes including ERG11 and ABC2 in itraconazole-resistant C. krusei isolates examined in this study.