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Gene silencing through RNA interference (RNAi) has revolutionized the study of gene function, particularly in non-model insects. However, in Lepidoptera (moths and butterflies) RNAi has many times proven to be difficult to achieve. Most of the negative results have been anecdotal and the positive experiments have not been collected in such a way that they are possible to analyze. In this review, we have collected detailed data from more than 150 experiments including all to date published and many unpublished experiments. Despite a large variation in the data, trends that are found are that RNAi is particularly successful in the family Saturniidae and in genes involved in immunity. On the contrary, gene expression in epidermal tissues seems to be most difficult to silence. In addition, gene silencing by feeding dsRNA requires high concentrations for success. Possible causes for the variability of success in RNAi experiments in Lepidoptera are discussed. The review also points to a need to further investigate the mechanism of RNAi in lepidopteran insects and its possible connection to the innate immune response. Our general understanding of RNAi in Lepidoptera will be further aided in the future as our public database at http://insectacentral.org/RNAi will continue to gather information on RNAi experiments., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

By using shotgun HPLC-ESI-MS proteomics approach, 2043 peptides were identified from the midgut of Spodoptera litura larvae at the sixth instar feeding stage, out of which 1489 (72.9%) were found to have their homologues in the public protein databases and 842 had identities of molecular functions. Seven-hundred forty-one peptides were annotated according to Gene Ontology Annotation in terms of molecular function, biological process, and cellular localization, with 336 and 251 peptides being related to catalytic activity and binding activity, respectively. Most of the catalytic proteins had activity of hydrolases, oxidoreductases and transferases and most of the binding proteins were involved in protein-binding activity. Among the annotated peptides, 487 were classified into different cellular processes and 490 were classified to locate in the cytoplasm. Nonredundant enzymes associated with the metabolisms of carbohydrates, lipids and fatty acids, amino acids and proteins, translation, transport, and stress resistance were identified. Presence and expression at high levels of numerous enzymes of glycolysis pathway, synthesis of proteins, and absorption and transport of fatty acids and lipids indicate that active metabolism processes of carbohydrates, proteins, and lipids occurred in the midgut of sixth instar feeding larvae of S. litura. The protein profile provides a basis for further study of the physiological events in the midgut of S. litura.

Interleukin-24 (IL-24)/melanoma differentiation associated gene-7 (mda-7) as a novel tumor-suppressor gene has potent antitumor activities in a broad spectrum of human cancers through the activation of various signaling pathways. However, the suppressive effect of adenovirus-mediated IL-24 (Ad-IL-24) expression on human laryngeal cancers is still elusive. In this study, we explored the therapeutic effect of Ad-IL-24 on human laryngeal cancers in vitro and in vivo in an athymic nude mouse model, using a Hep-2 human laryngocarcinoma cell line, and a WI-38 human diploid cell line served as a normal cell control. We demonstrated that Ad-IL-24 induced significant growth inhibition and apoptosis, upregulated the expression of P21, P27, and Bax, downregulated Bcl-2 expression, and activated caspase-3 in Hep-2 laryngeal tumor cells, while it exerted no direct effect on the in vitro proliferation of WI-38 normal diploid cells. Moreover, intratumoral injections of Ad-IL-24 in nude mice bearing Hep-2 tumors significantly suppressed the laryngeal xengrafted tumor growth and reduced microvessel density (MVD) and VEGF expression in tumors. This retarded tumor growth in vitro and in vivo elicited by Ad-IL-24 was closely associated with the upregulation of proliferation-related molecules P21 and P27, decrease in the ratio of anti- to proapoptotic molecules Bcl-2/Bax, followed by the activation of caspase-3, leading to apoptosis via intrinsic apoptotic pathways, and the reduced expression of proangiogenic factor VEGF involved in the inhibition of tumor angiogenesis. Thus, our results indicate that the potent, selective killing activity of Ad-IL-24 in laryngeal cancer cells, but not in normal cells, makes this vector a potential candidate for laryngeal cancer gene therapy.