METTL3 facilitates multiple myeloma tumorigenesis by enhancing YY1 stability and pri-microRNA-27 maturation in m6A-dependent manner.

Multiple myeloma (MM) is a pernicious plasma cell disorder and has a poor prognosis. N6-methyladenosine (m6A) is an abundant epigenetic RNA modification and is important in cancer progression. Nevertheless, the function of m6A and its regulator METTL3 in MM are rarely reported. Here, we identified the m6A "writers", METTL3, was enhanced in MM and found that Yin Yang 1 (YY1) and primary-miR-27a-3p were the potential target for METTL3. METTL3 promoted primary-miR-27a-3p maturation and YY1 mRNA stability in an m6A manner. YY1 also was found to facilitate miR-27a-3p transcription. METTL3 affected the growth, apoptosis, and stemness of MM cells through accelerating the stability of YY1 mRNA and the maturation of primary-miR-27a-3p in vitro and in vivo. Our results reveal the key function of the METTL3/YY1/miR-27a-3p axis in MM and may provide fresh insights into MM therapy.

Evaluation of herb-drug interaction of ambrisentan with shikonin based on UPLC-MS/MS.

CONTEXT: Ambrisentan is an oral endothelin-receptor antagonist (ERA). However, there is no report on the interaction between ambrisentan and shikonin. OBJECTIVE: To investigate the effect of shikonin on ambrisentan metabolism in vivo and in vitro. MATERIALS AND METHODS: This study developed an ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for simultaneous determination of ambrisentan and (S)-4-hydroxymethyl ambrisentan in rat plasma. Twelve male Sprague-Dawley (SD) rats were divided into two groups (n = 6): the control group and shikonin (20 mg/kg) group. The pharmacokinetics of ambrisentan (2.5 mg/kg) were investigated after 30 min. Additionally, human and rat liver microsomes were used to investigate the herb-drug interaction. RESULTS: The UPLC-MS/MS method was shown to be accurate, precise and reliable, and was successfully applied to the herb-drug interaction study of ambrisentan with shikonin. When co-administrated with 20 mg/kg shikonin, the Cmax and AUC(0-∞) of ambrisentan were significantly increased by 44.96 and 16.65%, respectively (p < 0.05). In addition, there were modest decreases in (S)-4-hydroxymethyl ambrisentan Cmax and AUC(0-∞) in the presence of shikonin (p < 0.05), which indicated that these results were in accordance with the inhibition of shikonin on ambrisentan metabolism. Moreover, enzyme kinetic study indicated that shikonin had an inhibitory effect on human and rat microsomes where the IC50 values of shikonin were 5.865 and 6.358 µM, respectively. CONCLUSIONS: Our study indicated that shikonin could inhibit ambrisentan metabolism. Further studies need to be carried out to verify whether similar interaction truly apply in humans and whether this interaction has clinical significance.

Liquid chromatography-tandem mass spectrometric method for the quantification of eliglustat in rat plasma and the application in a pre-clinical study.

Eliglustat is an oral substrate reduction therapy drug and has been approved as a first-line treatment for adults with Gaucher disease type 1 (GD 1). In the present study, we aimed to develop and establish an accurate and simple ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the measurement of eliglustat concentration in rat plasma. The goal of chromatographic separation of eliglustat and the internal standard (bosutinib) was finished on an Acquity BEH C18 (2.1 mm × 50 mm, 1.7 µm) column. Acetonitrile and 0.1% formic acid in water were employed as the mobile phase in a mode of gradient elution with the 0.40 mL/min flow rate. The detection was carried out on a XEVO TQ-S triple quadrupole tandem mass spectrometer coupled with electrospray ionization (ESI) interface in the positive-ion mode. Multiple reaction monitoring (MRM) was used to monitor the precursor-to-product ion transitions of m/z 405.4 → 84.1 for eliglustat and m/z 530.2 → 141.2 for bosutinib (IS), respectively. It was found that the linearity of the method in the range of 1-500 ng/mL was good for eliglustat. The values of intra- and inter-day accuracy and precision were all within the acceptance limits, and no matrix effect was found in this method. The current developed method was further performed to support in vivo pharmacokinetic study of eliglustat after oral treatment with 10 mg/kg eliglustat to rats.

Determination of four omega-3 polyunsaturated fatty acids by UPLC-MS/MS in plasma of hyperlipidemic and normolipidemic subjects.

BACKGROUND: Omega-3 polyunsaturated fatty acids (PUFAs), including alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and docosapentaenoic acid (DPA), play critical roles in numerous biochemical reactions. Our aim is to develop a rapid and sensitive method for simultaneous determination of ALA, EPA, DHA and DPA in the plasma of hyperlipidemic and normolipidemic subjects. METHODS: An ultra-high-performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method of ALA, EPA, DHA, and DPA was developed with chlorzoxazone as the internal standard (IS). The analytes were separated on an Acquity BEH C18 column (2.1 mm × 100 mm, 1.7 µm) with gradient elution by acetonitrile and 0.1% ammonia water. ALA, EPA, DHA, DPA, and IS were determined by negative electrospray ionization (ESI-) with multiple reaction monitoring (MRM) at m/z 277.42/259.05, 301.20/257.00, 327.30/283.40, 329.24/285.32, and 168.03/132.02. A total of 80 normolipidemic subjects and 83 hyperlipidemic subjects, who underwent testing for plasma lipids, liver and kidney functions, and blood routine blood test (BRT), were enrolled. RESULTS: There was good linearity for ALA within 1-10 µg/mL, and EPA, DHA and DPA were within 0.125-10 µg/mL. The relative standard deviation (RSD) of precision was below 15%. The concentrations of ALA, EPA, DHA and DPA were 3.47 ±â€¯2.58, 0.41 ±â€¯0.26, 2.93 ±â€¯1.39 and 0.25 ±â€¯0.21 µg/mL, respectively, in normolipidemic subjects, increasing to 4.14 ±â€¯3.71, 0.57 ±â€¯0.46, 3.43 ±â€¯2.13, 0.27 ±â€¯0.25 µg/mL, respectively in hyperlipidemic subjects. Among them, only the EPA concentration was significantly different between two groups. There was a high correlation between ALA, EPA, DHA and DPA. CONCLUSION: We developed a rapid and sensitive method for simultaneously determination of ALA, EPA, DHA and DPA in hyperlipidemic and normolipidemic subjects. In hyperlipidemic and normolipidemic subjects, concentrations of ALA were highest, followed by DHA, EPA and DPA; there were high degrees of correlation between each value.

Inhibition of autophagy enhances the targeted therapeutic effect of sorafenib in thyroid cancer.

The multi-target kinase inhibitor sorafenib has been approved for the treatment of patients with advanced differentiated thyroid cancer. However, different sensitivities to sorafenib have been observed, and few patients have benefited from sorafenib treatment in the long term. In the event of acquired resistance to sorafenib it is not beneficial to continue treatment in most patients. Autophagy can be induced in a variety of cancer treatments and plays an important role in cancer treatment. The role of autophagy in sorafenib treatment of thyroid cancer has not been fully demonstrated. The present study investigated whether autophagy is activated by sorafenib during the treatment of thyroid cancer, examined the underlying mechanisms, and explored potential strategies to enhance the therapeutic sensitivity of sorafenib. Chloroquine (CQ) is an autophagy inhibitor that has been reported to increase sensitivity to various cancer treatments. Thyroid cancer xenograft model mice were treated with sorafenib, CQ, or a combination of sorafenib and CQ. We observed that CQ or sorafenib treatment suppressed tumor growth, while mice treated with the combination of sorafenib and CQ displayed significantly reduced tumor growth compared with those treated with sorafenib or CQ alone. Western blotting results indicated that sorafenib concurrently inhibited the activities of the MAPK and AKT/mTOR pathways in thyroid cancer. Autophagy was activated by sorafenib in thyroid cancer, both in vitro and in vivo, which was at least in part due to suppression of the AKT/mTOR pathway. Combination treatment including CQ could inhibit the autophagic flux induced by sorafenib. Silencing the key autophagy gene ATG5 using small interfering RNA also increased the anticancer effect of sorafenib. In summary, the present study revealed that inhibition of autophagy enhances the anticancer effect of sorafenib, and the combination of CQ with sorafenib treatment represents a potential therapeutic strategy for treating advanced differentiated thyroid cancer.

Inhibition of the AKT/mTOR Pathway Augments the Anticancer Effects of Sorafenib in Thyroid Cancer.

BACKGROUND: Sorafenib is a multikinase inhibitor that has been approved for the treatment of patients with advanced 131iodine (131I) refractory differentiated thyroid cancer (DTC). However, the progression-free survival of patients with advanced 131I refractory DTC is short, and most DTC patients eventually acquire resistance to sorafenib. Therefore, new therapeutic strategies need to be developed. MATERIALS AND METHODS: The thyroid cancer cell lines 8505C and FTC133 were treated with sorafenib in the presence or absence of BEZ235 or small interfering RNA (siRNA) directed against AKT. A CCK8 kit was used to evaluate cell viability. Protein expression levels of relevant genes were determined by Western blotting analysis, whereas messenger RNA expression levels were determined by real-time PCR analysis. Flow cytometry was performed to assess the number of apoptotic cells. RESULTS: The results indicate that sorafenib simultaneously inhibited the activities of the MAPK and PI3K/AKT/mTOR pathways in thyroid cancer cells. Treatment of 8505C and FTC133 cells with NVP-BEZ235, siRNA against AKT, or sorafenib induced tumor cell apoptosis and led to reduced tumor cell proliferation. Sorafenib in combination with PI3K/AKT/mTOR inhibition by NVP-BEZ235 or AKT siRNA enhanced apoptosis and proliferation suppression. CONCLUSIONS: The evidence of this study suggests that a combinatorial approach that inhibits both the MAPK and PI3K/AKT/mTOR pathways exerts a greater antitumor effect than sorafenib alone in thyroid cancer cell lines.