Studying the Anti-Tumor Effects of siRNA Gene Silencing of Some Metabolic Genes in Pancreatic Ductal Adenocarcinoma.

BACKGROUND: Earlier diagnosis and advances in treatment strategies have increased the average survival of cancer patients over the last decades. Despite the increased number of new anti- neoplastic agents, there has been no adequate therapy for intricate malignancies, such as pancreatic cancer. Cancer metabolism is the main building block standing behind cancer promotion and progression, even in the presence of a harsh environment. Targeting metabolic pathways, such as glycolysis and pentose phosphate pathway, are regarded as a promising new strategy for cancer treatment. OBJECTIVE: The current study aimed to investigate the effects of knocking-down pancreatic cancer glycolytic and pentose phosphate pathway's regulators (HIF-1α, ARNT, PFKFB4, and RBKS) on cell's viability and resistance to Gemcitabine and Doxorubicin, using small interference RNA. METHODOLOGY: The human pancreatic ductal adenocarcinoma cell line, Panc-1, was used to study the anti-proliferative activity of targeting HIF-1α, ARNT, PFKFB4, and RBKS mRNAs by transfection with small interference RNAs, alone and in combination. The transfected cells were also treated with Doxorubicin and Gemcitabine to study the relationship between the concerned genes and the resistance of Panc-1 cells to these drugs. The effect on cell proliferation was determined using a colorimetric assay and Inhibitory Concentration ((IC50) calculation. A cross-talk study was done to investigate the silencing effect of one of the above genes on the expression of others using Real Time-Polymerase Chain Reaction. RESULTS: In vitro transfection with small interference-RNAs, siHIF-1α, siPFKFB4, and siARNT decreased tumor cell proliferation with a maximum effect shown by siPFKFB4; but there was no anti- proliferative effect with RBKS silencing. Suppression of transcription of HIF-1α, ARNT, PFKFB4, and RBKS sensitize pancreatic cancer cells, Panc-1, to Doxorubicin and Gemcitabine. CONCLUSION: This study demonstrated the major tumor-promoting and progressive effects of PFKFB4, while HIF-1α and ARNT had modulator effects in pancreatic cancer cells (Panc-1). RBKS had a chemo-resistant role, justifying its enhanced expression in Panc-1 cells, but not a proliferative one. Silencing of all genes of interest decreased Doxorubicin and Gemcitabine's resistance and improved their antitumor effect Din the pancreatic cancer cell line, Panc-1.

Aqueous core microcapsules as potential long-acting release systems for hydrophilic drugs.

We have previously optimized the internal phase separation process to give rise to aqueous core microcapsules with polymeric shells composed of poly(lactide-co-glycolide) (PLGA) or poly(lactide) (PLA). In this study, the ability of these microcapsules to act as controlled release platforms of the model hydrophilic drug phenobarbital sodium was tested. Furthermore, the effect of the initial amounts of drug and water added to the system during microcapsule synthesis was investigated. Finally, the effect of varying polymer properties such as end functionalities, molecular weights, and lactide to glycolide ratios, on the characteristics of the produced microcapsules was studied. This was done by utilizing seven different grades of the polyester polymers. It was demonstrated that, within certain limits, drug loading is nearly proportional to the initial amounts of drug and water. Furthermore, drug encapsulation studies demonstrated that ester termination and increases in polymeric molecular weight result in lower drug loading and encapsulation efficiency. Moreover, drug release studies demonstrated that ester termination, increases in molecular weight, and increases in the lactide to glycolide ratio all result in slower drug release; this grants the ability to tailor the drug release duration from a few days to several weeks. In conclusion, such minor variations in polymer characteristics and formulation composition can result in dramatic changes in the properties of the produced microcapsules. These changes can be fine-tuned to obtain desirable long-acting microcapsules capable of encapsulating a variety of hydrophilic drugs which can be used in a wide range of applications.