Translation efficiency driven by CNOT3 subunit of the CCR4-NOT complex promotes leukemogenesis

Protein synthesis is frequently deregulated during tumorigenesis. However, the precise contexts of selective translational control and the regulators of such mechanisms in cancer is poorly understood. Here, we uncovered CNOT3, a subunit of the CCR4-NOT complex, as an essential modulator of translation in myeloid leukemia. Elevated CNOT3 expression correlates with unfavorable outcomes in patients with acute myeloid leukemia (AML). CNOT3 depletion induces differentiation and apoptosis and delayed leukemogenesis. Transcriptomic and proteomic profiling uncovers c-MYC as a critical downstream target which is translationally regulated by CNOT3. Global analysis of mRNA features demonstrates that CNOT3 selectively influences expression of target genes in a codon usage dependent manner. Furthermore, CNOT3 associates with the protein network largely consisting of ribosomal proteins and translation elongation factors in leukemia cells. Overall, our work elicits the direct requirement for translation efficiency in tumorigenesis and propose targeting the post-transcriptional circuitry via CNOT3 as a therapeutic vulnerability in AML.

miR-148a-3p and DDX6 functional link promotes survival of myeloid leukemia cells

Regulation of gene expression at the RNA level is an important regulatory mechanism in cancers. However, post-transcriptional molecular pathways underlying tumorigenesis remain largely unexplored. In this study, we uncovered a functional axis consisting of microRNA (miR)-148a-3p, RNA helicase DDX6, and its downstream target TXNIP in Acute Myeloid Leukemia (AML). Using a DROSHA-knockout cell system to evaluate miR-mediated gene expression control, we comprehensively profiled putative transcripts regulated by miR-148a-3p and identified DDX6 as a direct target of miR-148a-3p in AML cells. DDX6 depletion induced cell cycle arrest, apoptosis, and differentiation while delaying leukemia development in vivo. Genome-wide assessment of DDX6 binding transcripts and gene expression profiling of DDX6-depleted cells revealed TXNIP, a tumor suppressor, as the functional downstream target of DDX6. Overall, our study identified DDX6 as a post-transcriptional regulator that is required for AML survival. We proposed the regulatory link between miR-148a-3p and DDX6 as a potential therapeutic target in leukemia.

Is there a correlation between dental caries and body mass index-for-age among adolescents in Iran?

AIM

Obesity in adolescents is a public health problem and is steadily increasing in many countries. The aim of this study was to investigate the association between age-and gender-specific body mass index (BMI-for-age) and dental caries among adolescents aged 12 -15 years in Rafsanjan, Iran.

MATERIALS AND METHODS

Following ethical approval, 747 students aged 12-15 years were randomly selected from 12 state and private secondary schools in Rafsanjan, Iran. The DMFT index (following World Health Organization criteria) was used to assess the subjects' previous and existing dental caries experience. The BMI (Body Mass Index) percentile was calculated using BMI-for-age criteria as underweight (< 5th percent), normal-weight (5th-85th percent), at risk of being overweight (> 85th and < 95th percent) and overweight (> or = 95th percent).

RESULTS

Of 353 males and 394 females examined, 7.5% were underweight, 72.8% were normal-weight, 13.8% were at risk of being overweight, and 5.9% were overweight. The mean DMFT was 2.83. There was no significant difference between DMFT scores amongst the BMI-for-age groups (underweight = 2.91, normal-weight = 2.92, at risk of overweight = 2.54, overweight = 2.34, p > 0.05). However, males were more likely to have caries than females (11% of males were caries-free, in comparison to 20.6% of females; p < 0.05).

CONCLUSION

Almost one in five adolescents (19.7%) examined were deemed to be at risk of being overweight, or were classified as overweight. There was no association between DMFT scores and BMI-for-age scores.