MiR-200b and miR-155 as predictive biomarkers for the efficacy of chemoradiation in locally advanced head and neck squamous cell carcinoma.

BACKGROUND: The predictive value of microRNAs (miRNAs) in tumour cells and infiltrating immune cells for the efficacy of chemoradiation (CRTX) in locally advanced head and neck squamous cell carcinoma (HNSCC) was evaluated. METHODS: Formalin-fixed, paraffin-embedded tumour material was collected from patients with locally advanced HNSCC treated within the ARO-0401 phase III trial with radiotherapy in combination with either 5-fluorouracil/cisplatin (CDDP-CRTX) or 5-fluorouracil/mitomycin C (MMC-CRTX). MiRNA and immune profiles were established in a test cohort of 48 oropharyngeal carcinoma (OPSCC) cases by Affymetrix miRNA microarrays and the nanoString PanCancer Immune Panel, respectively. Expression of miRNA candidates was measured in 149 HNSCC patients by real-time PCR. Interference of miRNA profiles with CRTX efficacy was determined by Kaplan-Meier and Cox regression analysis. RESULTS: Expression levels of five miRNAs (miR-27b, -130b, -200b, -451 and -532-5p) were significantly associated with overall survival after MMC-CRTX. Six different miRNAs (miR-125b, -146a, -150, -155, -187 and -342-5p) were correlated with overall survival after CDDP-CRTX. Validation by real-time PCR confirmed the predictive value of miR-200b and miR-155 in OPSCC, which was absent in hypopharyngeal carcinomas. MiR-146a was revealed as a prognostic marker for both CRTX regimens. MiR-200b expression was mainly associated with distant metastasis, whereas miR-155 correlated with local recurrence. MiR-155 and miR-146a were identified as surrogate markers for tumour-infiltrating lymphocytes. CONCLUSIONS: MiR-200b and miR-155 were established as potential markers for personalised treatment selection of two standard regimens of CRTX. The predictive role of miR-155 deserves further investigation, especially within the framework of clinical trials of CRTX/immune checkpoint inhibitor combinations.

Optimization of translation profiles enhances protein expression and solubility.

mRNA is translated with a non-uniform speed that actively coordinates co-translational folding of protein domains. Using structure-based homology we identified the structural domains in epoxide hydrolases (EHs) and introduced slow-translating codons to delineate the translation of single domains. These changes in translation speed dramatically improved the solubility of two EHs of metagenomic origin in Escherichia coli. Conversely, the importance of transient attenuation for the folding, and consequently solubility, of EH was evidenced with a member of the EH family from Agrobacterium radiobacter, which partitions in the soluble fraction when expressed in E. coli. Synonymous substitutions of codons shaping the slow-transiting regions to fast-translating codons render this protein insoluble. Furthermore, we show that low protein yield can be enhanced by decreasing the free folding energy of the initial 5'-coding region, which can disrupt mRNA secondary structure and enhance ribosomal loading. This study provides direct experimental evidence that mRNA is not a mere messenger for translation of codons into amino acids but bears an additional layer of information for folding, solubility and expression level of the encoded protein. Furthermore, it provides a general frame on how to modulate and fine-tune gene expression of a target protein.

Expression of M6 and M7 lysin in Mytilus edulis is not restricted to sperm, but occurs also in oocytes and somatic tissue of males and females.

Sperm proteins of marine sessile invertebrates have been extensively studied to understand the molecular basis of reproductive isolation. Apart from molecules such as bindin of sea urchins or lysin of abalone species, the acrosomal protein M7 lysin of Mytilus edulis has been analyzed. M7 lysin was found to be under positive selection, but mechanisms driving the evolution of this protein are not fully understood. To explore functional aspects, this study investigated the protein expression pattern of M7 and M6 lysin in gametes and somatic tissue of male and female M. edulis. The study employs a previously published monoclonal antibody (G26-AG8) to investigate M6 and M7 lysin protein expression, and explores expression of both genes. It is shown that these proteins and their encoding genes are expressed in gametes and somatic tissue of both sexes. This is in contrast to sea urchin bindin and abalone lysin, in which gene expression is strictly limited to males. Although future studies need to clarify the functional importance of both acrosomal proteins in male and female somatic tissue, new insights into the evolution of sperm proteins in marine sessile invertebrates are possible. This is because proteins with male-specific expression (bindin, lysin) might evolve differently than proteins with expression in both sexes (M6/M7 lysin), and the putative function of both proteins in females opens the possibility that the evolution of M6/M7 lysin is under sexual antagonistic selection, for example, mutations beneficial to the acrosomal function that are less beneficial the function in somatic tissue of females.