Polo­like kinase 1 selective inhibitor BI2536 (dihydropteridinone) disrupts centrosome homeostasis via ATM­ERK cascade in adrenocortical carcinoma.

Adrenocortical carcinoma (ACC) is a rare but malignant tumor. Surgical removal, radiotherapy and combined chemotherapy are commonly used to treat ACC. Despite efforts for several decades, the mortality rate of ACC remains high after treatments. Therefore, identifying a novel therapeutic molecule is important to increase the survival rate of patients with ACC. The centrosome is a microtubule organizing center, and it also functions as a signaling hub to coordinate cell cycle progression. Deficiencies in the regulation of centrosome copy numbers may cause cell cycle arrest or even apoptosis. BI2536 is a polo like kinase 1­selective inhibitor and has been tested for the treatment of several types of cancer, including lung, oral and gastric cancer. However, to the best of our knowledge, its effects on ACC have not yet been examined. The present study revealed that BI2536 inhibited Y1 ACC cell proliferation in a time­ and dose­dependent manner. BI2536 blocked cell cycle progression and also induced cell apoptosis as shown by flow cytometry. Furthermore, following BI2536 treatment, centrosome amplification was induced, which resulted in aberrant mitosis. In terms of the mechanism, BI2536 induced DNA damage as evidenced by γH2AX staining and comet assay, followed by activation of ATM serine/threonine kinase­ERK signaling to promote centrosome amplification. Therefore, the present study suggested that BI2536 could be used as an adjuvant therapy in the treatment of ACC, and also revealed the underlying molecular mechanism.

Therapeutic potential of nanoceria pretreatment in preventing the development of urological chronic pelvic pain syndrome: Immunomodulation via reactive oxygen species scavenging and SerpinB2 downregulation.

Urological chronic pelvic pain syndrome (UCPPS) manifests as pelvic pain with frequent urination and has a 10% prevalence rate without effective therapy. Nanoceria (cerium oxide nanoparticles [CNPs]) were synthesized in this study to achieve potential long-term pain relief, using a commonly used UCPPS mouse model with cyclophosphamide-induced cystitis. Transcriptome sequencing analysis revealed that serpin family B member 2 (SerpinB2) was the most upregulated marker in mouse bladder, and SerpinB2 was downregulated with CNP pretreatment. The transcriptome sequencing analysis results agreed with quantitative polymerase chain reaction and western blot analysis results for the expression of related mRNAs and proteins. Analysis of Gene Expression Omnibus (GEO) datasets revealed that SerpinB2 was a differentially upregulated gene in human UCPPS. In vitro SerpinB2 knockdown downregulated proinflammatory chemokine expression (chemokine receptor CXCR3 and C-X-C motif chemokine ligand 10) upon treatment with 4-hydroperoxycyclophosphamide. In conclusion, CNP pretreatment may prevent the development of UCPPS, and reactive oxygen species (ROS) scavenging and SerpinB2 downregulation may modulate the immune response in UCPPS.

Etoposide Triggers Cellular Senescence by Inducing Multiple Centrosomes and Primary Cilia in Adrenocortical Tumor Cells.

Etoposide (ETO) has been used in treating adrenocortical tumor (ACT) cells. Our previous study showed that ETO inhibits ACT cell growth. In the present study, we show that ETO treatment at IC50 (10 µM) inhibited ACT cell growth by inducing cellular senescence rather than apoptosis. Several markers of cellular senescence, including enlarged nuclei, activated senescence-associated ß-galactosidase activity, elevated levels of p53 and p21, and down-regulation of Lamin B1, were observed. We further found that ETO induced multiple centrosomes. The inhibition of multiple centrosomes accomplished by treating cells with either roscovitine or centrinone or through the overexpression of NR5A1/SF-1 alleviated ETO-induced senescence, suggesting that ETO triggered senescence via multiple centrosomes. Primary cilia also played a role in ETO-induced senescence. In the mechanism, DNA-PK-Chk2 signaling was activated by ETO treatment; inhibition of this signaling cascade alleviated multiple ETO-induced centrosomes and primary cilia followed by reducing cellular senescence. In addition to DNA damage signaling, autophagy was also triggered by ETO treatment for centrosomal events and senescence. Importantly, the inactivation of DNA-PK-Chk2 signaling reduced ETO-triggered autophagy; however, the inhibition of autophagy did not affect DNA-PK-Chk2 activation. Thus, ETO activated the DNA-PK-Chk2 cascade to facilitate autophagy. The activated autophagy further induced multiple centrosomes and primary cilia followed by triggering senescence.

Mechanistic and compositional studies of the autophagy-inducing areca nut ingredient.

BACKGROUND/PURPOSE: We previously found that the partially purified 30-100 kDa fraction of areca-nut-extract (ANE 30-100K) induces autophagy in different types of cells including oral carcinoma OECM-1 cells. This study was to analyze the composition and possible mechanisms of ANE 30-100K-induced autophagy (AIA). MATERIALS AND METHODS: Phenol-sulfuric acid method and high performance anion exchange chromatography were utilized to analyze the composition of ANE 30-100K. OECM-1 and esophageal CE81T/VGH cells were taken as the experimental models. Microscope and transmission electron microscope were used to observe morphological changes. Cell viability and specific proteins were respectively measured by XTT and Western bot assay. shRNA and chemical inhibitors were applied to assess the involvement of Atg5, caveolin, and proteasome in AIA. RESULTS: ANE 30-100K contains ∼67% carbohydrate, which is composed of fucose (5.938%), arabinose (24.631%), glucosamine (8.066%), galactose (26.820%), glucose (21.388%), and mannose (13.157%). After ANE 30-100K stimulation, CE81T/VGH cells showed intracellular vacuoles, acidic vesicles, double-membrane vacuoles, and elevated LC3-II level. ANE 30-100K-induced cytotoxicity and LC3-II accumulation were significantly inhibited by Atg5 knockdown. Furthermore, the endocytosis inhibitor (methyl-ß-cyclodextrin) and two caveolin shRNAs, as well as two proteasome inhibitors (lactacystin and epoxomicin), were shown to significantly attenuate ANE 30-100K-induced cytotoxicity and LC3-II accumulation in both OECM-1 and CE81T/VGH cells. CONCLUSION: The major components of ANE 30-100K are carbohydrates. CE81T/VGH also exhibited autophagic responses to ANE 30-100K. Caveolin-mediated endocytosis and proteasome are involved in AIA. This study may have provided new knowledges of the action mechanisms and compositions of ANE 30-100K.