KEMAJEMUKAN BUDAYA, DEMOKRASI, KOMUNIKASI, DAN INTEGRASI NASIONAL

Masalah integrasi nasional pun akhir-akhir ini kembali hangat diperbincangkan dan dipertanyakan. Orang pun bertanya-tanya tentang sebab-sebab dari konflik yang tak berkesudahan di Indonesia, sejak tahun-tahun terakhir pemerintahan Orde Baru (mulai sekitar tahun 1996), hingga sekarang. Apakah provokator pendukung rezim yang lama yang terus bekerja merongrong masyarakat kita? Atau memang sebenarnya masyarakat kita telah memendam benihbenih perselisihan tersebut sejak lama? Adakah yang salah dalam hubungan antarsuku, kelompok, agama dan golongan di negeri kita

Systemic delivery of E6/7 siRNA using novel lipidic particles and its application with cisplatin in cervical cancer mouse models

Small interfering RNA (siRNA) shows great promise in cancer therapy, but its effectiveness in vivo still remains a crucial issue for its transition into the clinics. Although the successful use of polyethylene glycol (PEG)ylated lipidic delivery systems have already been reported, most of the formulation procedures used are labour intensive and also result in unstable end products. We have previously developed a simple yet efficient hydration-of-freeze-dried- matrix (HFDM) method to entrap siRNA within lipid particles, in which the products exhibited superior stability. Here, we show that these HFDM-formulated particles are stable in the presence of serum and can deliver siRNA efficiently to tumours after intravenous administration. Using these particles, around 50% knockdown of the target gene expression was observed in tumours. With the use of siRNA targeting the E6/7 oncogenes expressed in cervical cancer, we showed a 50% reduction in tumour size. This level of tumour growth suppression was comparable to that achieved from cisplatin at the clinically used dose. Overall, our results demonstrate the feasibility of using HFDM-formulated particles to systematically administer E6/7-targeted siRNA for cervical cancer treatment. The simplicity of preparation procedure along with superior product stability obtained from our method offers an innovative approach for the in vivo delivery of siRNA

Flexibility of short-strand RNA in aqueous solution as revealed by molecular dynamics simulation:are A′-RNA and A-RNA distinct conformational structures?

We use molecular dynamics simulations to compare the conformational structure and dynamics of a 21-base pair RNA sequence initially constructed according to the canonical A-RNA and A'-RNA forms in the presence of counterions and explicit water. Our study aims to add a dynamical perspective to the solid-state structural information that has been derived from X-ray data for these two characteristic forms of RNA. Analysis of the three main structural descriptors commonly used to differentiate between the two forms of RNA namely major groove width, inclination and the number of base pairs in a helical twist over a 30 ns simulation period reveals a flexible structure in aqueous solution with fluctuations in the values of these structural parameters encompassing the range between the two crystal forms and more. This provides evidence to suggest that the identification of distinct A-RNA and A'-RNA structures, while relevant in the crystalline form, may not be generally relevant in the context of RNA in the aqueous phase. The apparent structural flexibility observed in our simulations is likely to bear ramifications for the interactions of RNA with biological molecules (e.g. proteins) and non-biological molecules (e.g. non-viral gene delivery vectors)

Inhibition of cervical cancer cell growth in vitro and in vivo with dual shRNAs

RNA interference (RNAi)-based gene silencing is widely used in laboratories for gene function studies and also holds a great promise for developing treatments for diseases. However, in vivo delivery of RNAi therapy remains a key issue. Lentiviral vectors have been employed for stable gene transfer and gene therapy and therefore are expected to deliver a stable and durable RNAi therapy. But this does not seem to be true in some disease models. Here, we showed that lentivirus delivered short-hairpin RNA (shRNA) against human papillomavirus (HPV) E6/E7 oncogenes were effective for only 2 weeks in a cervical cancer model. However, using this vector to carry two copies of the same shRNA or two shRNAs targeting at two different but closely related genes (HPV E6 and vascular endothelial growth factor) was more effective at silencing the gene targets and inhibiting cell or even tumor growth than their single shRNA counterparts. The cancer cells treated with dual shRNA were also more sensitive to chemotherapeutic drugs than single shRNA-treated cells. These results suggest that a multi-shRNA strategy may be a more attractive approach for developing an RNAi therapy for this cancer. Cancer Gene Therapy (2011) 18, 219-227; doi: 10.1038/cgt.2010.72; published online 19 November 201

Treatment of cervical cancer using RNA-interference against human papillomavirus oncogenes

Human papillomavirus (HPV) is the infectious agent responsible for the development of cervical cancer, with type 16 responsible for 50% of all cases. Cervical cancer remains the number one cancer killer of women under 50 worldwide, resulting in more than 270,000 deaths each year. Tumours caused by human HPV infection are an ideal model system for RNA interference-based cancer therapies as the oncogenes which cause cervical cancer, E6 and E7, are only expressed in cervical cancer cells. Furthermore, E6 and E7 are absolutely required for the ongoing proliferation of cervical cancer cells, as it has been demonstrated that upon their suppression, cells undergo apoptosis or senescence. In this study, siRNAs were designed that were directed against the HPV E6 and E7 oncogenes that simultaneously targeted both E6 and E7 with a single siRNA. These siRNAs were shown to reduce E7 protein levels by 80%. Following siRNA treatment, it was observed that there was reactivation of the p53 tumour suppressor pathway. The loss of E6 and E7 in cervical cancer cell lines resulted in a reduction in cellular viability concurrent with the induction of cellular senescence. RNA interference was specific as no effect on HPV-negative cells was observed. It was also shown in this study that RNAi against E6 and E7 oncogenes enhances the chemotherapeutic effect of cisplatin in HeLa cells following a combined treatment, resulting in a four-fold increase in cytotoxicity for the combined treatment as compared to cisplatin alone. Upon co-treatment with cisplatin and shRNA expressed from a plasmid, a decrease in E7 expression was observed with a concurrent increase in p53 protein levels over that seen with either treatment alone. These results provide strong evidence that loss of E6 and E7 results in increased sensitivity to cisplatin, and that this effect may occur as a result of increased p53 protein levels. This research also investigated the potential for a liposome-based system to facilitate the delivery of siRNA to tumours in vivo. It was demonstrated that liposomes produced by a lyophilisation method entrap nucleic acids with high efficiency (greater than 60%), can fully protect nucleic acids from digestion with nucleases, and are taken up by more than 90% of cells in culture. It was also demonstrated that these liposomes are able to accumulate at tumour sites in vivo in immune-competent mice. Despite excellent cellular uptake, siRNAs entrapped within liposomes were not transfection-competent, suggesting an inability of siRNAs to dissociate from liposomes, localize in the cytoplasm and become available to the silencing machinery. This research lays the groundwork for further development of effective liposomes for the in vivo delivery of siRNA nucleotides

siRNA and shRNA as anticancer agents in a cervical cancer model

We describe the protocols of using siRNAs, or shRNAs delivered by a lentiviral vector, as a means to silence cancer-causing genes. We use cervical cancer as a model to demonstrate the inhibition of the human papillomavirus (HPV) oncogenes E6 and E7 in cervical cancer cells by RNAi and inhibition of the cell growth in vitro and tumor growth in mouse models. The protocols include methods on siRNA and shRNA design, production of lentiviral-vectored shRNA, transfection or transduction of cervical cancer cells with siRNA or shRNA, and detection of the inhibitory effects of siRNA or shRNA both in vitro and in vitro

CFD BASED PREDICTION OF AERODYNAMIC TORSION REDUCTION OF HALE UAV WING WITH WING CONTROL SURFACES

Hlm. 7-1

RNA interference for the treatment of cancer

RNA interference (RNAi) is the latest new technology in the field of genetic medicine in which specific genes can be turned off, or silenced, so as to affect a therapeutic outcome. It can be highly specific, works in the nanomolar range and is far more effective than the antisense approaches popular 10-15 years ago. Here we review the field and explore the potential role of RNAi in cancer therapy, highlighting recent progress and examining the hurdles that must be overcome before this promising technology is ready for clinical use. (C) 2006 Prous Science. All rights reserved