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Abstract Background The atherogenic index of plasma (AIP) is composed of triglycerides and high-density lipoprotein cholesterol and is a novel marker for assessing the risk of atherogenicity and cardiometabolic health. An association between AIP and greater frequency of major adverse cardiovascular events (MACEs) in patients with type 2 diabetes mellitus and high cardiovascular (CV) disease risk has been reported. However, only few studies have examined the correlation between AIP and CV risk in general populations. We thus aimed to evaluate the relationship between AIP and CV diseases using a large-scale population dataset from the Korean National Health Insurance Service-National Health Screening Cohort (NHIS-HEALS). Methods A total of 514,866 participants were enrolled from the NHIS-HEALS and classified according to the AIP quartiles. We performed univariate and multivariate Cox proportional hazards regression analyses to determine the association between AIP and MACEs, CV events, and CV mortality. Results During follow-up, we documented 12,133, 11,055, and 1942 cases of MACEs, CV events, and CV mortality, respectively. The multivariate-adjusted hazard ratios [HRs; 95% confidence interval (CI)] for MACEs gradually and significantly increased with the AIP quartiles [1.113 (1.054–1.175) in Q2, 1.175 (1.113–1.240) in Q3, and 1.278 (1.209–1.350) in Q4], following an adjustment for the conventional CV risk factors, including age, sex, body mass index, smoking, alcohol drinking, physical activities, household income, fasting glucose, systolic blood pressure, low-density lipoprotein cholesterol, and estimated glomerular filtration rate. In subgroup analyses, the association of AIP with MACEs and CV events was particularly outstanding in patients with diabetes. Conclusions AIP was significantly associated with CV risks after adjusting for the traditional risk factors. Therefore, it may be used as an effective mass screening method to identify patients at a high risk of CV events.

The effect of the dipeptidyl peptidase-IV inhibitor gemigliptin alone or in combination with the heat shock protein 90 inhibitor NVP-AUY922 (AUY922) on survival of thyroid carcinoma cells was elucidated. The SW1736 and TPC-1 human thyroid carcinoma cells were used. Cell viability, the percentage of viable cells, cytotoxic activity, the percentage of apoptotic cells, and mitochondrial membrane potential were measured. To evaluate the combined effect of gemigliptin with AUY922, the interactions were estimated by calculating combination index. Gemigliptin led to cell death in conjunction with overexpression of the phosphorylated protein levels of Akt, extracellular signal–regulated kinase 1/2, and adenosine monophosphate–activated protein kinase. In gemigliptin-treated cells, wortmannin augmented cell death, whereas AZD6244 and compound C did not affect cell survival. Wortmannin decreased phosphorylated adenosine monophosphate–activated protein kinase protein levels, and AZD6244 increased phosphorylated Akt protein levels. Meanwhile, cotreatment of both gemigliptin and AUY922, compared with treatment of AUY922 alone, potentiated cell death. All the combination index values were lower than 1.0, suggesting synergistic cytotoxicity of gemigliptin with AUY922. In treatment of both gemigliptin and AUY922, compared with AUY922 alone, the protein levels of total and phosphorylated Akt, phosphorylated extracellular signal–regulated kinase 1/2, and phosphorylated adenosine monophosphate–activated protein kinase increased without alteration in those of total extracellular signal–regulated kinase 1/2 and total adenosine monophosphate–activated protein kinase. The percentage of apoptotic cells increased. The protein levels of Bax and cleaved poly (ADP-ribose) polymerase increased, whereas Bcl2 protein levels were unchanged, resulting in increment of Bax/Bcl2 ratio. Transfection of Bax small interfering RNA did not cause any variation in cell viability, the percentage of viable cells and cytotoxic activity. Our results demonstrate that gemigliptin exerts a cytotoxic activity with concomitant alterations in expression of Akt, extracellular signal–regulated kinase 1/2, and adenosine monophosphate–activated protein kinase in thyroid carcinoma cells. Furthermore, gemigliptin synergizes with AUY922 in induction of cytotoxicity via regulation of Akt, extracellular signal–regulated kinase 1/2, and adenosine monophosphate–activated protein kinase as well as involvement of Bcl2 family proteins in thyroid carcinoma cells.

The influence of celastrol alone or in combination with paclitaxel on survival of anaplastic thyroid carcinoma cells was investigated. In 8505C and SW1736 cells, after treatment of celastrol, cell viability decreased, and cytotoxic activity increased. The protein levels of heat shock protein (hsp) 90, hsp70, Bax, death receptor 5, cleaved caspase-3, cleaved poly (ADP-ribose) polymerase, phospho-extracellular signal-regulated kinase 1/2 (ERK1/2), and phospho-c-Jun N -terminal kinase (JNK) were elevated, and those of Bcl2, phospho-nuclear factor-kappaB (NF-κB), and total and phospho-Akt were reduced. The endoplasmic reticulum stress markers expression and reactive oxygen species production were enhanced. In celastrol-treated cells, N -acetylcysteine increased cell viability and phospho-NF-κB protein levels, and decreased reactive oxygen species production and cytotoxic activity. The protein levels of cyclooxygenase 2, phospho-ERK1/2, phospho-JNK and Bip were diminished. After treatment of both celastrol and paclitaxel, compared with paclitaxel alone, cell viability and the percentage of viable cells were reduced, and death rate and cytotoxic activity were elevated. The protein levels of phospho-ERK1/2, phospho-JNK, Bip, and cyclooxygenase 2, and reactive oxygen species production were enhanced. All of the Combination Index values calculated by Chou–Talalay equation were lower than 1.0, implying the synergism between celastrol and paclitaxel in induction of cell death. In conclusion, our results suggest that celastrol induces cytotoxicity through involvement of Bcl2 family proteins and death receptor, and modulation of phospho-NF-κB, Akt, and mitogen-activated protein kinase in association with endoplasmic reticulum stress and reactive oxygen species production in anaplastic thyroid carcinoma cells. Moreover, celastrol synergizes with paclitaxel in induction of cytotoxicity in anaplastic thyroid carcinoma cells.

In this study, the combined effect of doxorubicin with cucurbitacin B on survival of anaplastic thyroid carcinoma cells was evaluated. For experiments, 8505C and CAL62 human anaplastic thyroid carcinoma cells were used. Cell viability, the percentage of viable cells, and cytotoxic activity were measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, multiplexed cytotoxicity assay, and cytotoxicity assay, respectively. Reactive oxygen species production was measured. In experiments, doxorubicin and cucurbitacin B reduced cell viability in a dose- and time-dependent manner. Cotreatment of doxorubicin and cucurbitacin B, compared with treatment of doxorubicin alone, decreased the percentage of viable cells and increased cytotoxic activity. All of the combination index values were lower than 1.0, suggesting the synergism between doxorubicin and cucurbitacin B in induction of cytotoxicity. In cells treated with both doxorubicin and cucurbitacin B, compared with doxorubicin alone, the protein levels of cleaved poly(adenosine diphosphate-ribose) polymerase and cyclooxygenase 2 and reactive oxygen species production were enhanced. In contrast, the protein levels of B-cell chronic lymphocytic leukemia/lymphoma 2 and survivin and B-cell chronic lymphocytic leukemia/lymphoma 2/B-cell chronic lymphocytic leukemia/lymphoma 2–associated x protein ratio were diminished. The protein levels of Janus kinase 2 and signal transducer and activator of transcription 3 were reduced, while phospho-extracellular signal–regulated kinase 1/2 protein levels were elevated without change in total extracellular signal–regulated kinase 1/2 protein levels. These results suggest that doxorubicin synergizes with cucurbitacin B in induction of cytotoxicity in anaplastic thyroid carcinoma cells. Moreover, synergistic cytotoxicity of doxorubicin with cucurbitacin B is mediated by B-cell chronic lymphocytic leukemia/lymphoma 2 family proteins, survivin, and reactive oxygen species and modulated by Janus kinase 2/signal transducer and activator of transcription 3 and extracellular signal-regulated kinase 1/2 in anaplastic thyroid carcinoma cells.