Physiological and molecular mechanisms underlying salicylic acid-mitigated mercury toxicity in lemon balm (Melissa officinalis L.).

Mercury (Hg) is one of the most toxic heavy metals with strong negative effects on the plant growth and functions. Salicylic acid (SA) is an important signaling molecule which confers tolerance to metal toxicities but little is known about the mechanisms of SA-mediated alleviation of Hg stress. Here, physiochemical and molecular responses of Hg-stressed lemon balm (Melissa officinalis L.) to exogenous SA were investigated to reveal SA-induced tolerance mechanisms. The CHLG gene of lemon balm which encodes chlorophyll synthase was also partly isolated and sequenced for the first time. Hg stress markedly decreased growth, relative water content (RWC) and photosynthetic pigments of the plant. However, exogenous SA significantly mitigated the toxic effects of mercury on the growth and RWC and enabled plant to maintain chlorophylls to the similar levels of unstressed plants. Hg-induced oxidative damage was also reduced following treatment with SA and treated plants showed the lower extent of lipid peroxidation which was accompanied with the higher free proline and phenolics contents and elevation of the antioxidant capacity as evidenced by DPPH radical scavenging and FRAP assays. Moreover, SA treatment resulted in up-regulation of CHLG and phenylalanine ammonia-lyase (PAL) genes as key components of chlorophyll and phenylpropanoid routes, respectively. Our results collectively indicate the ameliorative effects of exogenous SA in mercury toxicity through coordinated alternations in plant metabolic processes which provide insights to better understand mechanisms of Hg tolerance in lemon balm plant.

Critical microRNAs in Lung Cancer: Recent Advances and Potential Applications.

BACKGROUND: MicroRNAs (miRNAs) play an important role in the regulation of various genes involved in cell growth, development and the maintenance of body homeostasis. They are closely linked to different human diseases, particularly in cancers. Amplification and overexpression of some miRNAs that are called 'oncomiRs' or down-regulation of tumor suppressor miRNAs are associated with genetic alterations that are sufficient to drive tumorigenesis in humans. Lung cancer is the leading cause of cancer-related deaths worldwide. The high mortality rate of lung cancer is not changed even with recent advances in cancer treatment. Several studies demonstrated that miRNAs are involved in the pathogenesis of lung cancer that they negatively or positively regulate gene and protein expression by acting as oncogenes or tumor suppressors. OBJECTIVE: This article reviewed the current knowledge on the role of miRNAs and their target genes in lung cancer and discussed the potential use of some miRNAs as novel therapeutic agents in lung cancer. METHOD: Firstly, we collected and summarized all research and review and research articles in databases including Scopus and PubMed. Then, we used related keywords that are important to lung cancer target therapy and their diagnostic and prognostic values. RESULTS: Based on collected articles and research, recognizing critical microRNA and controlling the expression of this microRNA by antagonist oligonucleotides like antagomiRs or anti-miRs and microRNA mimicking will have a remarkable role in treating lung cancer. CONCLUSION: Many research studies have shown that a combination of chemotherapy plus knockdown or mimicking microRNA is effective and useful in the cancers treatment like lung cancer.