Aptamers are oligonucleotide sequences with a length of about 25−80 bases which have abilities to bind to specific target molecules that rival those of monoclonal antibodies. They are attracting great attention in diverse clinical translations on account of their various advantages, including prolonged storage life, little batch-to-batch differences, very low immunogenicity, and feasibility of chemical modifications for enhancing stability, prolonging the half-life in serum, and targeted delivery. In this Review, we demonstrate the emerging aptamer discovery technologies in developing advanced techniques for producing aptamers with high performance consistently and efficiently as well as requiring less cost and resources but offering a great chance of success. Further, the diverse modifications of aptamers for therapeutic applications including therapeutic agents, aptamer−drug conjugates, and targeted delivery materials are comprehensively summarized.

Autophagy enables cells to recycle long-lived proteins or damaged organelles. Beclin 1 plays important roles in autophagy, differentiation, apoptosis and the development and progression of cancer, but the expression of Beclin 1 and its possible role in primary intrahepatic cholangiocarcinoma (ICC) has not been reported yet. This study aimed to investigate Beclin 1 expression and its prognostic significance in ICC. First, we assessed the expression levels of Becn1 by real-time PCR in 50 ICC samples and found Becn1 mRNA expression was markedly increased in 78% (39 of 50) samples compared with normal bile duct epithelium. Beclin 1 protein expression in 108 tumor specimens from patients diagnosed with ICC was examined by immunohistochemistry and the correlation between Beclin 1 expression and clinicopathological factors were investigated. Immunopositivity for Beclin 1 was found in 72.2% (78 of 108) samples and low Beclin 1 expression was significantly associated with lymph node metastasis. The correlation between Beclin 1 expression and metastasis was validated in 46 ICC samples with lymph node metastasis. In survival analysis, low Beclin 1 expression was associated with worse overall survival (OS; p = 0.025) and disease-free survival (DFS; p = 0.027). In multivariate analysis, Beclin 1 expression, intrahepatic metastasis, lymph node metastasis and tumor size were found to be independent prognostic factors of OS. Thus, our results suggested the expression of Beclin 1 was correlated with progression and metastasis of ICC and it might serve as a novel prognostic marker for patients with ICC.

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Intrahepatic cholangiocellular carcinomas (ICCs) are usually fatal neoplasms originating from bile duct epithelia. However, many cholangiocarcinoma cells are shown to be resistant to chemotherapeutic drugs, which induce cell apoptosis. The role of autophagy and the therapeutic value of autophagy-associated genes are largely unknown in ICC. Here, we showed that autophagy was activated in nutrient starvation and xenograft cholangiocarcinoma cells. Furthermore, expression of autophagic genes and their autophagic activity were higher in clinical ICC specimens than that in normal cholangiocytes separated by laser capture microdissection. Inhibition of autophagy by autophagy inhibitors or siRNA, cholangiocarcinoma cells showed detention of proliferation and increase of apoptosis during nutrient starvation. In addition, autophagy inhibitor treatment or knockdown of beclin 1 suppressed tumor growth and sensitized ICC cells to chemotherapeutic agent-induced cell death. In conclusion, our data showed that autophagy is activated in ICC, and inactivation of autophagy may lead to cell apoptosis and enhance chemotherapy sensitivity. Intrahepatic cholangiocellular carcinoma (ICC) is a malignant neoplasm originating from epithelium of the biliary tree with high mortality. 1 ICC accounts for 5-30% of all primary liver malignancies, and its incidence has been increasing over the last several decades. 2 The mortality from intrahepatic cholangiocarcinoma is very high, with the 5-year survival rates being o15-20% in most series. 3,4 However, the exact molecular mechanisms of biliary epithelium malignant transformation are not well understood. Despite improved diagnostic and operative techniques, the prognosis of ICC remains poor. 5 Indeed, ICC is a type of cancer highly resistant to conventional antineoplastic medicines, 4 which is partially attributed to the property of insensitivity to cell death induced by cytotoxic agents. It is well known that the avoidance of apoptosis is one of the hallmarks of cancer cells, 6 and that failure to induce apoptosis by anticancer treatments contributes to chemotherapeutic failure and tumor progression. Although autophagy, an alternative caspase-independent cell death program, 7 is thought to be used for cancer treatment, its underlying molecular mechanism is still controversial in antineoplastic therapy and also in tumor progression.Autophagy is a conserved catabolic process by which cells themselves digest their organelles. 8 Autophagy has emerged as a homeostatic mechanism regulating the turnover of long-lived or damaged proteins and organelles, and buffering metabolic stress induced under starvation conditions by recycling intracellular constituents. 9 Autophagosomes engulfing organelles then fuse with lysosomes and mature into autolysosomes. Autophagic processes have been well characterized in yeast, and 430 autophagy-related genes that encode the proteins executing autophagy have been identified in the field of yeast genetics. 6,7 The amino acids and fatty acids generated by autophagic degr...

Purpose: The correlation of the hedgehog signaling pathway with the progression, prognosis, and therapeutics of intrahepatic cholangiocellular carcinoma (ICC) has not been well documented. The study aimed to investigate the expression, prognostic significance, and therapeutic value of hedgehog components in ICC.Experimental Design: Two independent cohorts of 200 patients with ICC were enrolled. By real-time PCR and immunohistochemistry assay, hedgehog components expression was evaluated. The prognostic values of hedgehog proteins were identified and verified. Cyclopamine or siRNA-targeting Gli was used to block the hedgehog signaling. Cell proliferation and apoptosis were observed by CCK8, cell cycle, and annexin V staining assays. In vivo murine tumor model was used to evaluate the role of hedgehog in ICC.Results: In ICC tissues, the Gli1 nuclear immune-intensity was associated with intrahepatic metastasis and the expression of Gli2 was associated with intrahepatic metastasis, venous invasion, and Unio Internationale Contra Cancrum (UICC) pT characteristics. In survival analysis, high Gli1 or Gli2 expressers had an unfavorable overall survival (OS) prognosis and a shorter disease-free survival (DFS) than those with low expression. In multivariate analysis, Gli1 expression was found to be an independent prognostic factor of OS, which was validated by another independent cohort. Furthermore, blocking the hedgehog signaling by cyclopamine or siRNA-targeting Gli1 resulted in apoptosis and growth inhibition in ICC cells.Conclusions: This study shows, for the first time, activation of hedgehog pathway associated with the progression and metastasis in ICC, which may provide prognostic and therapeutic values for this tumor.