A Critical Function for the Transcription Factors GLI1 and GLI2 in the Proliferation and Survival of Human Mast Cells.

Mast cell hyperactivity and accumulation in tissues are associated with allergy and other mast cell-related disorders. However, the molecular pathways regulating mast cell survival in homeostasis and disease are not completely understood. As glioma-associated oncogene (GLI) proteins are involved in both tissue homeostasis and in the hematopoietic system by regulating cell fate decisions, we sought to investigate the role for GLI proteins in the control of proliferation and survival of human mast cells. GLI1 transcripts were present in primary human mast cells and mast cell lines harboring or not activating mutations in the tyrosine kinase receptor KIT (HMC-1.1 and HMC-1.2, and LAD2 cells, respectively), while GLI2 transcripts were only present in HMC-1.1 and HMC-1.2 cells, suggesting a role for oncogenic KIT signaling in the regulation of GLI2. Reduction in GLI activity by small molecule inhibitors, or by shRNA-mediated knockdown of GLI1 or GLI2, led to increases in apoptotic cell death in both cultured human and murine mast cells, and reduced the number of peritoneal mast cells in mice. Although GLI proteins are typically activated via the hedgehog pathway, steady-state activation of GLI in mast cells occurred primarily via non-canonical pathways. Apoptosis induced by GLI silencing was associated with a downregulation in the expression of KIT and of genes that influence p53 stability and function including USP48, which promotes p53 degradation; and iASPP, which inhibits p53-induced transcription, thus leading to the induction of p53-regulated apoptotic genes. Furthermore, we found that GLI silencing inhibited the proliferation of neoplastic mast cell lines, an effect that was more pronounced in rapidly growing cells. Our findings support the conclusion that GLI1/2 transcription factors are critical regulators of mast cell survival and that their inhibition leads to a significant reduction in the number of mast cells in vitro and in vivo, even in cells with constitutively active KIT variants. This knowledge can potentially be applicable to reducing mast cell burden in mast cell-related diseases.

Applying the Noninferiority Paradigm to Assess Exposure-Response Similarity and Dose Between Pediatric and Adult Patients.

The use of extrapolation of efficacy in pediatric drug development programs is possible when disease progression and treatment response are similar in adult and pediatric populations. Historically, the exposure-response (E-R) similarity was assessed by visual inspection of 2 E-R curves to support pediatric extrapolation. The aim of this study was to develop a quantitative framework to describe the E-R relationship and the difference in E-R between pediatric and adult patients based on accumulated experience in pediatric drug development programs. Using clinical data for 8 drugs with either a linear or nonlinear E-R relationship, we adapted the methodology used in noninferiority testing to assess the E-R similarity between adult and pediatric patients at the targeted drug exposure. We implemented bootstrap-based and Bayesian-based methodologies to estimate the probability of concluding noninferiority of the E-R relationship. This approach provides objective criteria that can be applied to an assessment of E-R noninferiority in 2 populations to support extrapolation of efficacy in drug development programs from adults to pediatric populations.

Creatinine-Based Renal Function Assessment in Pediatric Drug Development: An Analysis Using Clinical Data for Renally Eliminated Drugs.

The estimated glomerular filtration rate (eGFR) equations based on serum creatinine (SCR) have been used for pediatric dose adjustment in drug labeling. This study evaluated the performance of those equations in estimating individual clearance of drugs that are predominantly eliminated by glomerular filtration, using clinical data from the renally eliminated drugs gadobutrol, gadoterate, amikacin, and vancomycin. The eGFR was compared with the observed drug clearance (CL) in 352 pediatric patients from birth to 12 years of age. Multiple eGFR equations overestimated the drug CL on average, including the original and bedside Schwartz equations, which showed an average eGFR/CL ratio between 1 and 3. Further analysis with bedside Schwartz equation showed a higher eGFR/CL ratio in the subjects with a lower SCR or CL. Supraphysiological eGFR as high as 380 mL/min/1.73 m2 was obtained using the bedside Schwartz equation for some of the subjects, most of whom are children < 2 years of age with SCR < 0.2 mg/dL. Excluding the subjects with supraphysiological eGFR from the analysis did not change the overall trend of overestimation. In conclusion, Schwartz equations led to an overestimation of drug clearance for the drugs evaluated. When greater precision is required in predicting eGFR for pediatric patients, such as in drug dosing, revised k constants for the Schwartz equation or new methods of glomerular filtration rate estimation may be necessary.

Corrected QT interval prolongation during anesthetic induction for laryngeal mask airway insertion with or without cisatracurium.

Objective This study was performed to observe the occurrence of corrected QT (QTc) interval prolongation during anesthetic induction for laryngeal mask airway insertion and the effects of cisatracurium administration on the QTc interval. Methods Eighty-eight patients were assigned to two groups: the cisatracurium administration group (n = 45) and non-cisatracurium administration group (n = 43). The QTc interval was continuously recorded by a 12-lead Holter electrocardiogram beginning in the hospital ward and continuing until after anesthetic induction. Results In the cisatracurium administration group, the QTc interval significantly increased from 417.9 ± 27.9 to 451.6 ± 32.5 ms after arrival in the operating room and significantly decreased to 432.4 ± 32.5 ms after a 15-minute rest; it significantly increased to 459.7 ± 23.8 ms again after propofol and fentanyl injection. However, the QTc interval decreased after cisatracurium injection. In the non-cisatracurium administration group, the QTc interval initially showed changes similar to those in the cisatracurium group until fentanyl and propofol were injected. Conclusions The QTc interval was significantly prolonged on arrival in the operating room and after propofol and fentanyl injection. The QTc interval did not significantly change by laryngeal mask airway insertion regardless of the administration of cisatracurium.

Vitamin D Enhances the Efficacy of Irinotecan through miR-627-Mediated Inhibition of Intratumoral Drug Metabolism.

Cytochrome P450 enzyme CYP3A4 is an important drug-metabolizing enzyme, and high levels of tumoral expression of CYP3A4 are linked to drug resistance. We investigated the function of vitamin D-regulated miR-627 in intratumoral CYP3A4 suppression and its role in enhancing the efficacy of chemotherapy. We found that miR-627 targets CYP3A4 and suppresses CYP3A4 expression in colon cancer cell lines. Furthermore, calcitriol (the active form of vitamin D) suppressed CYP3A4 expression by activating miR-627. As a result, calcitriol inhibited CYP3A4-mediated metabolism of irinotecan (a topoisomerase I inhibitor) in cancer cells. We show that calcitriol enhanced the efficacy of irinotecan in growth inhibition and apoptosis induction. When miR-627 is inhibited, calcitriol fails to enhance the activity of irinotecan. In addition, overexpression of miR-627 or siRNA knockdown of CYP3A4 enhanced the efficacy of irinotecan in growth inhibition and apoptosis induction. In contrast, overexpression of CYP3A4 abolished the effects of calcitriol on the activity of irinotecan. Using a nude mouse xenograft model, we demonstrated that calcitriol inhibited CYP3A4 and enhanced the in vivo antitumor activity of irinotecan without causing side effects. Our study identified a novel target for improving cancer therapy, i.e., modulating the intratumoral CYP3A4-mediated drug metabolism with vitamin D. This strategy could enhance the therapeutic efficacy without eliciting the side effects. Mol Cancer Ther; 15(9); 2086-95. ©2016 AACR.

Specific Delivery of MiRNA for High Efficient Inhibition of Prostate Cancer by RNA Nanotechnology.

Both siRNA and miRNA can serve as powerful gene-silencing reagents but their specific delivery to cancer cells in vivo without collateral damage to healthy cells remains challenging. We report here the application of RNA nanotechnology for specific and efficient delivery of anti-miRNA seed-targeting sequence to block the growth of prostate cancer in mouse models. Utilizing the thermodynamically ultra-stable three-way junction of the pRNA of phi29 DNA packaging motor, RNA nanoparticles were constructed by bottom-up self-assembly containing the anti-prostate-specific membrane antigen (PSMA) RNA aptamer as a targeting ligand and anti-miR17 or anti-miR21 as therapeutic modules. The 16 nm RNase-resistant and thermodynamically stable RNA nanoparticles remained intact after systemic injection in mice and strongly bound to tumors with little or no accumulation in healthy organs 8 hours postinjection, and subsequently repressed tumor growth at low doses with high efficiency.

MicroRNA-627 mediates the epigenetic mechanisms of vitamin D to suppress proliferation of human colorectal cancer cells and growth of xenograft tumors in mice.

BACKGROUND & AIMS: Vitamin D protects against colorectal cancer through unclear mechanisms. We investigated the effects of calcitriol (1α,25-dihydroxyvitamin D3; the active form of vitamin D) on levels of different microRNAs (miRNAs) in colorectal cancer cells from humans and xenograft tumors in mice. METHODS: Expression of miRNAs in colorectal cancer cell lines was examined using the Ambion mirVana miRNA Bioarray. The effects of calcitriol on expression of miR-627 and cell proliferation were determined by real-time polymerase chain reaction and WST-1 assay, respectively; growth of colorectal xenograft tumors was examined in nude mice. Real-time polymerase chain reaction was used to analyze levels of miR-627 in human colon adenocarcinoma samples and nontumor colon mucosa tissues (controls). RESULTS: In HT-29 cells, miR-627 was the only miRNA significantly up-regulated by calcitriol. Jumonji domain containing 1A (JMJD1A), which encodes a histone demethylase, was found to be a target of miR-627. By down-regulating JMJD1A, miR-627 increased methylation of histone H3K9 and suppressed expression of proliferative factors, such as growth and differentiation factor 15. Calcitriol induced expression of miR-627, which down-regulated JMJD1A and suppressed growth of xenograft tumors from HCT-116 cells in nude mice. Overexpression of miR-627 prevented proliferation of colorectal cancer cell lines in culture and growth of xenograft tumors in mice. Conversely, blocking the activity of miR-627 inhibited the tumor suppressive effects of calcitriol in cultured colorectal cancer cells and in mice. Levels of miR-627 were decreased in human colon adenocarcinoma samples compared with controls. CONCLUSIONS: miR-627 mediates tumor-suppressive epigenetic activities of vitamin D on colorectal cancer cells and xenograft tumors in mice. The messenger RNA that encodes the histone demethylase JMJD1A is a direct target of miR-627. Reagents designed to target JMJD1A or its messenger RNA, or increase the function of miR-627, might have the same antitumor activities of vitamin D without the hypercalcemic side effects.