Search

Insearch of a unique and reliable contrast agent targeting pancreaticadenocarcinoma, new multifunctional nanoparticles (MnMEIO-silane-NH2-(MUC4)-mPEG NPs) were successfully developed in this study.Mucin4-expression levels were determined through different imagingstudies in a panel of pancreatic tumor cells (HPAC, BxPC-3, and Panc-1)both in vitro and in vivo studies. The in vitro T2-weighted MR imaging study in HPAC and Panc-1 tumor cellstreated with NPs showed −89.1 ± 5.7% and −0.9 ±0.2% contrast enhancement, whereas in in vivo study, it is found tobe −81.5 ± 4.5% versus −19.6 ± 5.2% (24 hpostinjection, 7.0 T), respectively. The T2-weighted MR and optical imaging studies revealed that the novelcontrast agent can specifically and effectively target to mucin4-expressingtumors in nude mice. Hence, it is suggested that MnMEIO-silane-NH2-(MUC4)-mPEG NPs are able to provide an efficient and targeteddelivery of MUC4 antibodies to mucin4-expressing pancreatic tumors. [ABSTRACT FROM AUTHOR]

Purpose: Sonic hedgehog (Shh) signaling is critical to embryogenesis and resistance to chemotherapy. We aimed to examine the role of Shh signaling in the response to radiation of human hepatocellular carcinoma (HCC) cells. Methods and Materials: Response to ionizing radiation therapy (RT) was evaluated by clonogenic assay. Quantitative RT—polymerase chain reaction for patched-1 (PTCH-1) expression was performed. Cytosolic accumulation of Shh and nuclear translocation of Gli-1 were assessed by immunofluorescence. Gli-1 knockdown was done by RNA interference (RNAi). Immunoprecipitation was performed to detect Shh ligand in conditioned medium. Immunofluorescent stain for γ-H2AX was used as an index of DNA double strand breaks (DSB). Expression of proteins related to DNA damage repair was assessed by Western blotting. Results: We found that Shh ligand could protect human HCC HA22T and Sk-Hep1 cells against RT. In HA22T cells, Shh ligand activated the Shh signaling with upregulation of Shh, PTCH-1, and Gli-1 expression. The nuclear translocation of Gli-1 further supports the activation of Gli-1. The radioprotection by Shh ligand was partly blocked by Shh antibody neutralization and was abolished by Gli-1 RNAi, suggesting a critical role of Shh signaling in radiation resistance. Furthermore, we noted that soluble factors secreted into conditioned medium, either constitutively or responding to radiation, by HA22T or Sk-Hep1 cells protected subsequent culturing cells against RT. Immunoprecipitation shows the presence of Shh peptide in conditioned medium. Intriguingly, antibody neutralization of Shh ligand or knockdown of Gli-1 reversed the radioprotective effect of conditioned medium. Furthermore, Shh ligand reduced the RT-induced phosphorylation of checkpoint kinase 1 and impaired the repair of DNA DSB. Conclusions: Activation of Shh signaling protects HCC cells against ionizing radiation in an autocrine manner. Impairment of DNA damage repair might involve mechanism of Shh-induced radioresistance. Targeting Shh signaling pathway may be a novel strategy to enhance the radioresponse of human HCC cells. [Copyright &y& Elsevier]

A clerodane diterpene compound 16-hydroxycleroda-3,13-dien-15,16-olide (CD) is considered a therapeutic agent with pharmacological activities. The present study investigated the mechanisms of CD-induced apoptosis in T24 human bladder cancer cells. CD inhibited cell proliferation in a concentration and time-dependent manner. CD-induced overproduction of reactive oxygen species and reduced mitochondrial membrane potential, associated with reduced expression of Bcl-2 and increased levels of cytosolic cytochrome c, cleaved PARP-1 and caspase-3. In addition, CD treatment led to cell cycle arrest at the G0/G1 phase and inhibited expression of cyclin D1 and cyclin-dependent kinases 2 and 4 and led to increased levels of p21, p27Kip1 and p53. All of these events were accompanied with a reduction of pEGFR, pMEK1/2, pERK1/2, pAkt, pmTOR, pP70S6K1, HIF-1α, c-Myc and VEGF. RNAseq-based analysis revealed that CD-induced cell death was characterised by an increased expression of stress and apoptotic-related genes as well as inhibition of the cell cycle-related genes. In summary, CD induces apoptosis in T24 bladder cancer cells through targeting multiple intracellular signaling pathways as a result of oxidative stress and cell cycle arrest. [ABSTRACT FROM AUTHOR]

Esophageal cancer prognosis remains poor in current clinical practice. We previously reported that moscatilin can induce apoptosis and mitotic catastrophe in esophageal cancer cells, accompanied by upregulation of polo-like kinase 1 (Plk1) expression. We aimed to validate in vitro activity and Plk1 expression in vivo following moscatilin treatment and to examine the treatment's radiosensitizing effect. Human esophageal cancer cells were implanted in nude mice. Moscatilin was intraperitoneally (i.p.) injected into the mice. Tumor size, body weight, white blood cell counts, and liver and renal function were measured. Aberrant mitosis and Plk1 expression were assessed. Colony formation was used to measure survival fraction after radiation. Moscatilin significantly suppressed tumor growth in mice bearing human esophageal xenografts without affecting body weight, white blood cell counts, or liver and renal function. Moscatilin also induced aberrant mitosis and apoptosis. Plk1 expression was markedly upregulated in vivo. Moreover, moscatilin pretreatment enhanced CE81T/VGH and BE3 cell radioresponse in vitro. Moscatilin may inhibit growth of human esophageal tumors and sensitize esophageal cancer cells to radiation therapy. [ABSTRACT FROM AUTHOR]

6-(methylsulfinyl) hexyl isothiocyanate (6-MITC) is a naturally occurring compound isolated from Wasabia japonica (wasabi). The synthetic derivatives, 6-(methylsulfenyl) hexyl isothiocyanate (I7447) and 6-(methylsulfonyl) hexyl isothiocyanate (I7557), were derived from 6-MITC with the deletion and addition of oxygen, respectively. We aimed to evaluate the effect of these synthetic compounds on human oral cancer cells, SAS and OECM-1. All three compounds (I7447, 6-MITC, and I7557) inhibited the viability of SAS and OECM-1 cells using MTT assay. Morphological observations showed various proportions of mitotic arrest and apoptosis in cells treated with these compounds. Cell cycle analysis revealed relatively abundant G2/M arrest in 6-MITC and I7557-treated cells, whereas sub-G1 accumulation was found in I7447-treated cells. In using phosphorylated histone H3 as a marker for mitosis, the addition of 6-MITC and I7557 (excluding I7447) could be shown to arrest cells during mitosis. In contrast, I7447 induced more prominent apoptosis than the 6-MITC or I7557 compounds. The down-regulated expression of the phosphorylated form of CHK1 and Cdc25c was noted in 6-MITC and I7557-treated cells. I7557 could sensitize SAS cells to death by radiation. The wasabi compound, 6-MITC, and its chemical derivatives with different numbers of oxygen may have differential pharmacological effects on human oral cancer cells. [ABSTRACT FROM AUTHOR]

Innate or acquired drug resistance and consequent tumor relapse in lung cancer patients have been linked to activities of cancer stem cells (CSCs). Therefore, targeting CSCs is suggested as an effective approach for non-small cell lung cancer (NSCLC) therapy. In this study, we demonstrated that garcinol, a polyisoprenylated benzophenone isolated from fruiting bodies of Garcinia indica, and possessing anti-inflammatory, antioxidant, acetyltransferase inhibitory, and anticancer activities, modulates activities of lung CSCs (LCSCs) and their associated aggressiveness. Herein, we demonstrated the inhibitory effect of garcinol on the LCSC phenotype of human NSCLC cells using analytical drug cytotoxicity or cell viability, flow cytometric, and functional assay approaches. Garcinol significantly diminished the ability of the H441 and A549 NSCLC cell lines to form spheres. In parallel assays, garcinol inhibited differentiated lung cancer cell and LCSC viability in dose-dependent manners. Consistent with these observations, flow cytometric data showed that garcinol reduced the putative LCSC pool, evidenced by the dose-dependent decreasing proportion of side-population (SP) cells and associated ALDH activity in garcinol-treated H441 cells, compared to the control group. Additionally, functional assays showed that garcinol markedly diminished the ability of H441 and A549 cells to form colonies. Mechanistically, garcinol impaired phosphorylation of LRP6, a co-receptor of Wnt and STAT3. In the same assay, garcinol down-regulated β-catenin, Dvl2, Axin2, and cyclin D1 expressions in NSCLC-generated spheres, suggesting its ability to regulate the Wnt/β-catenin signaling pathway. The results were further verified in vivo using H441 LCSC mouse xenograft model where administration of garcinol significantly inhibited tumor growth. Taken together, we demonstrated herein that garcinol modulates the LCSC phenotype via regulation of Wnt/β-catenin signaling and inactivation of STAT3, thus showing that garcinol may be a putative novel anti-LCSC therapeutic agent. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: Human WWOX gene encoding WW domain-containing oxidoreductase, named WWOX, FOR, or WOX1, has been studied in various types of cancer cells and shown to be a tumor suppressor with pro-apoptotic properties. Mutation or gain-of-function of p53 in glioma cells is associated with resistance to radiation therapy and poor prognosis. In this study, we overexpressed WOX1 to examine the pro-apoptotic activity against human glioblastoma cells harboring mutant p53. Methods: Overexpression of WOX1 in glioblastoma cell lines and apoptosis-related assays were performed. Results: Our results showed that overexpressed WOX1 induced apoptosis of glioblastoma U373MG harboring mutant p53 by causing hypoploidy and DNA fragmentation. However, ectopic WOX1 had no effect with U87MG possessing wild type p53. Unlike temozolomide, WOX1 induced apoptosis of U373MG cells via a mitochondria-independent and caspase-3-independent pathway. Conclusions: Overexpression of WOX1 preferentially inhibited viability and induced apoptosis in human glioblastoma cells expressing mutant p53 via a mechanism independent of the intrinsic apoptotic pathway. Conceivably, the survival of human glioblastoma cells depends upon interactions between the gain-of-function of p53 and WOX1. This suggests that modulation of WOX1 expression may be a novel strategy for treating human glioblastoma cells with mutant p53. [Copyright &y& Elsevier]

Abstract: Purpose: Bcr-Abl fusion protein activates tyrosine kinase, resulting in the proliferation of leukemia cells, especially chronic myeloid leukemia (CML) cells. Imatinib (IM) effectively targets Bcr-Abl tyrosine kinase, but development of resistance to IM occurs with varying frequency. Methods: Elucidation of the common regulatory pathway upstream of Bcr-Abl in IM-sensitive and IM-resistant CML cells is important for developing novel therapeutics against CML. Results: This study demonstrated that IM preferentially inhibited the viability and Bcr-Abl expression in IM-sensitive K562 (K562) cells, but not in Bcr-Abl overexpressing IM-resistant K562 (K562R) cells. Both K562 and K562R cells expressed Shh preproprotein, cleaved Shh C-terminal and N-terminal peptides, as well as mRNA level of major Shh signaling molecules, including sonic hedgehog (Shh), patched (PTCH), smoothened (Smo) and Gli-1. Moreover, Gli-1 translocation into nucleus was evident in these two cell lines, suggesting that both K562 and K562R cells possess activated and major components of the Shh signaling pathway. Silencing of Gli-1 by interference RNA was accompanied by inhibition of Bcr-Abl protein expression. Pharmacological suppression of Bcr-Abl expression was restored by the Smo agonist purmorpharmine. Treatment of Shh peptide in both K562 and K562R cells not only increased Shh and Gli-1 expression, but also up-regulated Bcr-Abl expression. Resveratrol, a known Bcr-Abl inhibitor, reduced Gli-1 activation and inhibited the viability of CML cells. Conclusions: Shh signaling may regulate Bcr-Abl expression in human chronic myeloid leukemia cells. Novel compounds inhibiting both Shh signaling and Bcr-Abl expression, such as resveratrol, may have potential to be effective agents against CML independent of IM resistance. [Copyright &y& Elsevier]

Abstract: Resveratrol exerts functions relating apoptosis and differentiation; nonetheless, the mechanisms remain unclear. We examined the regulation of resveratrol on apoptosis and erythrocytic (E)-differentiation in leukaemia cells. The results showed that resveratrol treatment for 24h induced apoptosis in human leukaemia NB4, HL-60, and U937 cells. Resveratrol-treated K562 cells underwent erythrocyte (E)-differentiation and cell cycle arrest in S-phase, without apoptotic induction in the early stage, but with marked apoptosis in the later stages. Resveratrol-induced apoptosis could be accompanied by P38 downregulation, and E-differentiation could occur with PI3K/Akt upregulation. Downstream NF-κB was increased by resveratrol treatment for 24h, while luciferase activity was decreased by resveratrol treatment for 72h. Similar changes were discovered for nuclear levels and NF-κB-DNA binding activity. In conclusion, resveratrol induced differential responses through different signalling pathways, including PI3K/Akt and P38/MAPK, leading to opposing expressions of NF-κB. NF-κB could be a switch for regulating E-differentiation and apoptosis in resveratrol-stimulated K562 cells. [Copyright &y& Elsevier]