[Cardiac pacemaker deprogramming by electrocautery. An update]

Novel approaches in cancer treatment: preclinical and clinical development of small non-coding RNA therapeutics

Short or small interfering RNAs (siRNAs) and microRNA (miRNAs) are molecules similar in size and function able to inhibit gene expression based on their complementarity with mRNA sequences, inducing the degradation of the transcript or the inhibition of their translation.

siRNAs bind specifically to a single gene location by sequence complementarity and regulate gene expression by specifically targeting transcription units via posttranscriptional gene silencing. miRNAs can regulate the expression of different gene targets through their imperfect base pairing.

This process - known as RNA interference (RNAi) - modulates transcription in order to maintain a correct physiological environment, playing a role in almost the totality of the cellular pathways.

siRNAs have been evolutionary evolved for the protection of genome integrity in response to exogenous and invasive nucleic acids such as transgenes or transposons. Artificial siRNAs are widely used in molecular biology for transient silencing of genes of interest. This strategy allows to inhibit the expression of any target protein of known sequence and is currently used for the treatment of different human diseases including cancer.

Modifications and rearrangements in gene regions encoding for miRNAs have been found in cancer cells, and specific miRNA expression profiles characterize the developmental lineage and the differentiation state of the tumor. miRNAs with different expression patterns in tumors have been reported as oncogenes (oncomirs) or tumor-suppressors (anti-oncomirs). RNA modulation has become important in cancer research not only for development of early and easy diagnosis tools but also as a promising novel therapeutic approach.

Despite the emerging discoveries supporting the role of miRNAs in carcinogenesis and their and siRNAs possible use in therapy, a series of concerns regarding their development, delivery and side effects have arisen.

In this review we report the biology of miRNAs and siRNAs in relation to cancer summarizing the recent methods described to use them as novel therapeutic drugs and methods to specifically deliver them to cancer cells and overcome the limitations in the use of these molecules.

Long transcripts minus touchdown qPCR (LTMT-qPCR): a simplified and convenient method for the screening and quantification of microRNA profiles

Due to the short length and differences in abundance of microRNAs, microRNA profile screening and quantification is challenging. In this study, we found that size selection magnetic beads could be employed to easily and efficiently remove long RNA transcripts. After removing the long transcripts, the remaining small RNAs could be concentrated and then reverse-transcribed using universal stem-loop primers (USLP), with six randomized nucleotides at the 3' end region. The efficiency of reverse transcription decreased when the number of randomized nucleotides was reduced. In addition, we found that touchdown qPCR improved microRNA profile detection, with lower C_T values and better detection efficiency than the regular qPCR protocol, especially for those low-abundance microRNAs. Finally, we incorporated these observations to create a new protocol we named long transcripts minus touchdown qPCR (LTMT-qPCR). We performed a side-by-side comparison of LTMT with USLP and traditional stem-loop primer (TSLP) protocols. We found that LTMT has higher detection efficiency than USLP, especially for the detection of low-abundance microRNAs. Although LTMT was equivalent to TSLP in terms of microRNA profile detection, LTMT is more convenient, user-friendly, and cost-effective. Taken together, the present data indicate that LTMT is a simple, rapid, and user-friendly approach that has higher precision, accuracy, and sensitivity than the previously described methods, making it more suitable for microRNA profile screening and quantification.

Bronchoscopic ablation techniques in the management of lung cancer

Central airway involvement is a common manifestation of lung cancer during the disease course. Some patients will require bronchoscopic therapeutic interventions to palliate symptoms, or less commonly to provide more definitive therapy of airway involvement. We describe an overview specifically of bronchoscopic ablative techniques that are available for use in malignant airway obstruction. Techniques that are more commonly used include bronchoscopic application of laser, electrocautery, argon plasma coagulation (APC), cryotherapy and mechanical debulking techniques. Less commonly employed are brachytherapy and photodynamic therapy. These techniques may be applied via flexible or rigid bronchoscopy depending upon the clinical scenario. The choice of technique depends on available tools and expertise, the urgency of the clinical scenario, and whether the lesion is predominately endobronchial, extrinsic compression, or a combination of both. Malignant airway obstruction is a common finding in lung cancer and there are a number of effective bronchoscopic ablative techniques that may be employed safely to palliate patients with a significant symptom burden.