RB1CC1-enhanced autophagy facilitates PSCs activation and pancreatic fibrogenesis in chronic pancreatitis.

Chronic pancreatitis (CP) is described as a progressive fibro-inflammatory disorder of the exocrine disease, which eventually leads to damage of the gland. Excessive activation of pancreatic stellate cells (PSCs) is a critical participant in the initiation of CP. Autophagy is involved in multiple degeneration and inflammation in acute pancreatitis and CP. In our study, we report that retinoblastoma coiled coil protein 1 (RB1CC1) expression and the autophagic level are elevated in activated PSCs. RB1CC1 is positively correlated with pancreatic fibrogenesis in tissues and plasma of CP patients. Knockdown of RB1CC1 restrains alpha smooth muscle actin (α-SMA) and collagen expressions, and autophagy in activated PSCs in vitro. Furthermore, we show that RB1CC1 induces PSC activation via binding to ULK1 promoter and the direct interaction with ULK1 protein. These suppress ULK1 expression and its kinase activity. In mice, knockdown of RB1CC1 blocks autophagy and then inhibits the pancreatic duct ligation-induced pancreatic fibrosis. Consequently, our study highlights that RB1CC1-mediated autophagy is a key event for the activation of PSCs. Inhibition of RB1CC1 alleviates autophagy, which plays a critical role in anti-fibrotic activation in PSCs and CP progression. RB1CC1 could be a novel strategy for the treatment of pancreatic fibrosis.

Role of piwi-interacting RNA-651 in the carcinogenesis of non-small cell lung cancer.

Piwi-interacting RNAs (piRNAs/piRs) are small non-coding RNAs that can serve important roles in genome stability by silencing transposable genetic elements. piR651, one of these novel piRNAs, regulates a number of biological functions, as well as carcinogenesis. Previous studies have reported that piR651 is overexpressed in human gastric cancer tissues and in several cancer cell lines, including non-small cell lung cancer (NSCLC) cell lines. However, the role of piRNAs in carcinogenesis has not been clearly defined. In the present study, a small interfering RNA inhibitor of piR651 was transfected into the NSCLC A549 and HCC827 cell lines to evaluate the effect of piR651 on cell growth. The association between piR651 expression and apoptosis was evaluated by flow cytometry and western blot analysis. Wound-healing and Transwell migration and invasion assays were used to determine the effect of piR651 on the migration and invasion of NSCLC cell lines. The results revealed that inhibition of piR651 inhibited cell proliferation and significantly increased the apoptotic rate compared with the negative control (NC), as well as altering the expression of apoptosis-associated proteins. There were fewer migrating and invading cells in the piR651-inhibited group than in the NC group in the Transwell assays. Furthermore, in the wound-healing assay, the wound remained wider in the piR651 inhibitor group, suggesting decreased cell migration compared with that in the NC group. The results of the present study demonstrate that piR651 potentially regulates NSCLC tumorigenic behavior by inhibiting cell proliferation, migration and invasion and by inducing apoptosis. Therefore, piR651 is a potential cancer diagnosis marker.

Plasma and tumor levels of Linc-pint are diagnostic and prognostic biomarkers for pancreatic cancer.

Long intergenic non-protein coding RNA, p53 induced transcript (Linc-pint) is a long noncoding RNA (lncRNA) that regulates tumor cell viability and proliferation. We used qRT-PCR and RNA FISH analysis to evaluate Linc-pint levels in the plasma and tumor tissues of pancreatic cancer (PCa) patients. Our data demonstrate that Linc-pint expression is lower in plasma samples from PCa patients than from healthy individuals, and indicate that plasma Linc-pint levels are more sensitive than CA19-9 for detecting PCa. Our data also show that Linc-pint levels are lower in PCa tumors than in adjacent tissues, carcinoma of the ampulla of Vater (CAV) and cholangiocarcinoma (CCA), and suggest that Linc-pint could be used for distinguishing the cause of malignant obstructive jaundice. Low plasma Linc-pint levels correlate with tumor recurrence, while low tumor Linc-pint levels correlate with poor prognosis for PCa patients after pancreatectomy. These results thus indicate that low plasma Linc-pint expression could serve as a minimally invasive biomarker for early PCa detection, and that low Linc-pint levels in PCa tumors could be used for predicting patient prognosis.

EF24 inhibits tumor growth and metastasis via suppressing NF-kappaB dependent pathways in human cholangiocarcinoma.

A synthetic monoketone analog of curcumin, termed 3, 5-bis (2-flurobenzylidene) piperidin-4-one (EF24), has been reported to inhibit the growth of a variety of cancer cells both in vitro and in vivo. However, whether EF24 has anticancer effects on cholangiocarcinoma (CCA) cells and the mechanisms remain to be investigated. The aim of our study was to evaluate the molecular mechanisms underlying the anticancer effects of EF24 on CCA tumor growth and metastasis. Cell proliferation, apoptosis, migration, invasion, tumorigenesis and metastasis were examined. EF24 exhibited time- and dose-dependent inhibitory effects on HuCCT-1, TFK-1 and HuH28 human CCA cell lines. EF24 inhibited CCA cell proliferation, migration, and induced G2/M phase arrest. EF24 induced cell apoptosis along with negative regulation of NF-κB- X-linked inhibitor of apoptosis protein (XIAP) signaling pathway. XIAP inhibition by lentivirus mediated RNA interference enhanced EF24-induced apoptosis, while XIAP overexpression reduced it in CCA cells. In vivo, EF24 significantly suppressed the growth of CCA tumor xenografts and tumor metastasis while displaying low toxicity levels. Our findings indicate that EF24 is a potent antitumor agent that inhibits tumor growth and metastasis by inhibiting NF-κB dependent signaling pathways. EF24 may represent a novel approach for CCA treatment.

Long Noncoding RNA MALAT1 Promotes Aggressive Pancreatic Cancer Proliferation and Metastasis via the Stimulation of Autophagy.

Recently, pancreatic ductal adenocarcinoma (PDAC) has emerged as one of the most aggressive malignant tumors with the worst prognosis. Previous studies have demonstrated that long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is increased in pancreatic cancer and is identified as a diagnostic biomarker. Nonetheless, the molecular mechanism of elevated MALAT1 levels and tumor aggressiveness remains unknown. In this study, MALAT1 was found to be highly expressed in PDAC tissues, and elevated expression was associated with poorer prognoses. In addition, MALAT1 was positively linearly correlated with the expression of LC3B mRNA. Furthermore, several molecules involved in cellular autophagic flux were modulated following the downregulation of MALAT1, including LC3, P62, and LAMP-2. Mechanistically, we found that MALAT1 interacted with RNA binding protein HuR, and silencing of MALAT1 greatly enhanced the posttranscriptional regulation of TIA-1 and had further effects on inhibiting autophagy. MALAT1 was speculated to regulate tumorigenesis via HuR-TIA-1-mediated autophagic activation. Hence, we investigated the biological properties of MALAT1 in terms of tumor proliferation and metastasis by promoting autophagy in vitro In brief, these data demonstrate that MALAT1 could facilitate the advanced progression of tumors in vivo Our study highlights the new roles of MALAT1 on protumorigenic functioning and anticancer therapy via activating autophagy in pancreatic cancer. Mol Cancer Ther; 15(9); 2232-43. ©2016 AACR.

Protective Effects of Hydrogen Gas on Experimental Acute Pancreatitis.

Acute pancreatitis (AP) is an inflammatory disease mediated by damage to acinar cells and pancreatic inflammation. In patients with AP, subsequent systemic inflammatory responses and multiple organs dysfunction commonly occur. Interactions between cytokines and oxidative stress greatly contribute to the amplification of uncontrolled inflammatory responses. Molecular hydrogen (H2) is a potent free radical scavenger that not only ameliorates oxidative stress but also lowers cytokine levels. The aim of the present study was to investigate the protective effects of H2 gas on AP both in vitro and in vivo. For the in vitro assessment, AR42J cells were treated with cerulein and then incubated in H2-rich or normal medium for 24 h, and for the in vivo experiment, AP was induced through a retrograde infusion of 5% sodium taurocholate into the pancreatobiliary duct (0.1 mL/100 g body weight). Wistar rats were treated with inhaled air or 2% H2 gas and sacrificed 12 h following the induction of pancreatitis. Specimens were collected and processed to measure the amylase and lipase activity levels; the myeloperoxidase activity and production levels; the cytokine mRNA expression levels; the 8-hydroxydeoxyguanosine, malondialdehyde, and glutathione levels; and the cell survival rate. Histological examinations and immunohistochemical analyses were then conducted. The results revealed significant reductions in inflammation and oxidative stress both in vitro and in vivo. Furthermore, the beneficial effects of H2 gas were associated with reductions in AR42J cell and pancreatic tissue damage. In conclusion, our results suggest that H2 gas is capable of ameliorating damage to the pancreas and AR42J cells and that H2 exerts protective effects both in vitro and in vivo on subjects with AP. Thus, the results obtained indicate that this gas may represent a novel therapy agent in the management of AP.

Artesunate Protects Against Sepsis-Induced Lung Injury Via Heme Oxygenase-1 Modulation.

Artesunate, a derivative of artemisinin, has anti-inflammatory properties and exerts protective roles in sepsis. Heme oxygense-1 (HO-1) inhibits the inflammatory response through reduction of proinflammatory cytokines and leukocyte influx into tissues. The present study investigated the effects of artesunate on HO-1 and septic lung injury. Cecal ligation and puncture (CLP) was employed to induce septic lung injury. Mice pretreated with artesunate (AS) (15 mg/kg) exhibited decreased sepsis-induced mortality and lung injury and alleviated lung pathological changes and neutrophil infiltration. In addition, AS lowered the levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the serum and bronchoalveolar lavage fluid (BALF) and inhibited cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase isoform (iNOS) expression and NF-κB activation in lung tissue. In addition, AS enhanced NF-E2-related factor-2 (Nrf2) activation and HO-1 expression and enzymatic activity in lung tissue. However, the protective effects of AS on sepsis-induced lung injury were eliminated by ZnPP IX, an HO-1 competitive inhibitor. Therefore, AS plays protective roles in septic lung injury related to the upregulation of HO-1. These findings suggest an effective and applicable treatment to sepsis-induced lung injury and provide new insights into the molecular mechanisms and actions of AS.

The activation of c-Jun NH2-terminal kinase is required for dihydroartemisinin-induced autophagy in pancreatic cancer cells.

BACKGROUND: c-Jun NH2-terminal kinases (JNKs) are strongly activated by a stressful cellular environment, such as chemotherapy and oxidative stress. Autophagy is a protein-degradation system in which double-membrane vacuoles called autophagosomes are formed. The autophagy-related gene Beclin 1 plays a key role in this process. We previously found that autophagy was induced by dihydroartemisinin (DHA) in pancreatic cancer cells. However, little is known about the complex relationship between ROS, JNK activation, autophagy induction, and Beclin 1 expression. METHODS: Cell viability and CCK-8 assays were carried out to determine the cell proliferation; small interfering RNAs (siRNAs) were used to knockdown c-Jun NH2-terminal kinases (JNK1/2) genes; western blot was performed to detect the protein expression of LC3, JNK, Beclin 1, caspase 3 and ß-actin; production of intracellular ROS was analyzed using FACS flow cytometry; autophagy induction was confirmed by electron microscopy. RESULTS: In the present study, we explored the role of DHA and Beclin 1 expression in autophagy. DHA-treated cells showed autophagy characteristics, and DHA also activated the JNK pathway and up-regulated the expression of Beclin 1. Conversely, blocking JNK signaling inhibited Beclin 1 up-regulation. JNK activation was found to primarily depend on reactive oxygen species (ROS) resulting from the DHA treatment. Moreover, JNK pathway inhibition and Beclin 1 silencing prevented the induction of DHA-induced autophagy. CONCLUSIONS: These results suggest that the induction of autophagy by DHA is required for JNK-mediated Beclin 1 expression.

Sphere-forming tumor cells possess stem-like properties in human fibrosarcoma primary tumors and cell lines.

Fibrosarcoma is a malignant soft tissue tumor of mesenchymal origin. Despite advances in medical and surgical treatment, patient survival rates have remained poor. According to the cancer stem cell hypothesis, tumors are comprised of heterogeneous cell populations that have different roles in tumor formation and growth. Cancer stem cells are a small cell subpopulation that exhibits stem-like properties to gain aggressiveness and recurrence. These cells have been identified in a variety of cancerous tumors, but not in human fibrosarcoma. In this study, we observed that HT1080 cells and primary fibrosarcoma cells formed spheres and showed higher self-renewal capacity, invasiveness and drug resistance compared with their adherent counterparts. Moreover, we demonstrated that the cells showed higher expression of the embryonic stem cell-related genes Nanog, Oct3/4, Sox2, Sox10 and their encoding proteins, as well as greater tumorigenic capacity in nude mice. In conclusion, our data suggest the presence of a stem-like cell population in human fibrosarcoma tumors, which provides more evidence for the cancer stem cell hypothesis and assistance in designing new therapeutic strategies against human fibrosarcoma.

Dihydroartemisinin enhances Apo2L/TRAIL-mediated apoptosis in pancreatic cancer cells via ROS-mediated up-regulation of death receptor 5.

BACKGROUND: Dihydroartemisinin (DHA), a semi-synthetic derivative of artemisinin, has recently shown antitumor activity in various cancer cells. Apo2 ligand or tumor necrosis factor-related apoptosis-inducing ligand (Apo2L/TRAIL) is regarded as a promising anticancer agent, but chemoresistance affects its efficacy as a treatment strategy. Apoptosis induced by the combination of DHA and Apo2L/TRAIL has not been well documented, and the mechanisms involved remain unclear. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report that DHA enhances the efficacy of Apo2L/TRAIL for the treatment of pancreatic cancer. We found that combined therapy using DHA and Apo2L/TRAIL significantly enhanced apoptosis in BxPC-3 and PANC-1 cells compared with single-agent treatment in vitro. The effect of DHA was mediated through the generation of reactive oxygen species, the induction of death receptor 5 (DR5) and the modulation of apoptosis-related proteins. However, N-acetyl cysteine significantly reduced the enhanced apoptosis observed with the combination of DHA and Apo2L/TRAIL. In addition, knockdown of DR5 by small interfering RNA also significantly reduced the amount of apoptosis induced by DHA and Apo2L/TRAIL. CONCLUSIONS/SIGNIFICANCE: These results suggest that DHA enhances Apo2L/TRAIL-mediated apoptosis in human pancreatic cancer cells through reactive oxygen species-mediated up-regulation of DR5.

Escin augments the efficacy of gemcitabine through down-regulation of nuclear factor-κB and nuclear factor-κB-regulated gene products in pancreatic cancer both in vitro and in vivo.

PURPOSE: Pancreatic cancer is an aggressive malignancy, which generally develops resistance to chemotherapy. Agents that are safe and can sensitize cancer to chemotherapy are urgently needed. Escin, a natural mixture of triterpene saponins isolated from Aesculus wilsonii Rehd, has been demonstrated to possess anti-cancer activity both in vitro and in vivo. The anti-cancer activity of escin could be, in part, due to the inactivation of nuclear factor-κB (NF-κB). In contrast, chemotherapy including gemcitabine could activate NF-κB and lead to chemoresistance. Here, for the first time, we investigated whether escin, via the inactivation of NF-κB, would potentiate the antitumor activity of gemcitabine in pancreatic cancer. METHODS: Cell viability and proliferation, apoptosis, NF-κB activity and the expression of NF-κB-linked genes were all examined in vitro. The antitumor effect of escin with or without gemcitabine in pancreatic cancer was also assessed using BxPC-3 xenografts subcutaneously established in BALB/c nude mice. RESULTS: Escin not only potentiated the proliferation-inhibiting and apoptosis-inducing effect of gemcitabine in both BxPC-3 and PANC-1 cell lines in vitro, but also dramatically enhanced its suppressive effect on tumor growth in nude mice. The mechanism is at least partially due to the inhibition of NF-κB activity and consequent inhibition of c-Myc, COX-2, Cyclin D1, Survivin, Bcl-2 and Bcl-xL, and the activation of caspase-3. CONCLUSION: These data suggest that escin, via inactivation of NF-κB, could potentiate the efficacy of gemcitabine in combating pancreatic cancer, which could be a novel and potentially important therapeutic approach for the treatment for pancreatic cancer.

Nuclear factor-κB-dependent epithelial to mesenchymal transition induced by HIF-1α activation in pancreatic cancer cells under hypoxic conditions.

BACKGROUND: Epithelial to mesenchymal transition (EMT) induced by hypoxia is one of the critical causes of treatment failure in different types of human cancers. NF-κB is closely involved in the progression of EMT. Compared with HIF-1α, the correlation between NF-κB and EMT during hypoxia has been less studied, and although the phenomenon was observed in the past, the molecular mechanisms involved remained unclear. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report that hypoxia or overexpression of hypoxia-inducible factor-1α (HIF-1α) promotes EMT in pancreatic cancer cells. On molecular or pharmacologic inhibition of NF-κB, hypoxic cells regained expression of E-cadherin, lost expression of N-cadherin, and attenuated their highly invasive and drug-resistant phenotype. Introducing a pcDNA3.0/HIF-1α into pancreatic cancer cells under normoxic conditions heightened NF-κB activity, phenocopying EMT effects produced by hypoxia. Conversely, inhibiting the heightened NF-κB activity in this setting attenuated the EMT phenotype. CONCLUSIONS/SIGNIFICANCE: These results suggest that hypoxia or overexpression of HIF-1α induces the EMT that is largely dependent on NF-κB in pancreatic cancer cells.

Oxalate impairs aminophospholipid translocase activity in renal epithelial cells via oxidative stress: implications for calcium oxalate urolithiasis.

PURPOSE: We evaluated the possible involvement of phospholipid transporters and reactive oxygen species in the oxalate induced redistribution of renal epithelial cell phosphatidylserine. MATERIALS AND METHODS: Madin-Darby canine kidney cells were labeled with the fluorescent phospholipid NBD-PS in the inner or outer leaflet of the plasma membrane and then exposed to oxalate in the presence or absence of antioxidant. This probe was tracked using a fluorescent quenching assay to assess the bidirectional transmembrane movement of phosphatidylserine. Surface expressed phosphatidylserine was detected by annexin V binding assay. The cell permeable fluorogenic probe DCFH-DA was used to measure the intracellular reactive oxygen species level. RESULTS: Oxalate produced a time and concentration dependent increase in phosphatidylserine, which may have resulted from impaired aminophospholipid translocase mediated, inward directed phosphatidylserine transport and from enhanced phosphatidylserine outward transport. Adding the antioxidant N-acetyl-L-cysteine significantly attenuated phosphatidylserine externalization by effectively rescuing aminophospholipid translocase activity. CONCLUSIONS: To our knowledge our findings are the first to show that oxalate induced increased reactive oxygen species generation impairs aminophospholipid translocase activity and decreased aminophospholipid translocase activity has a role in hyperoxaluria promoted calcium oxalate urolithiasis by facilitating phosphatidylserine redistribution in renal epithelial cells.

Dihydroartemisinin inhibits angiogenesis in pancreatic cancer by targeting the NF-κB pathway.

PURPOSE: Dihydroartemisinin (DHA) has recently shown antitumor activity in human pancreatic cancer cells. However, its effect on antiangiogenic activity in pancreatic cancer is unknown, and the mechanism is unclear. This study was aimed to investigate whether DHA would inhibit angiogenesis in human pancreatic cancer. METHODS: Cell viability and proliferation, tube formation of human umbilical vein endothelial cells (HUVECs), nuclear factor (NF)-κB DNA-binding activity, expressions of vascular endothelial growth factor (VEGF), interleukin (IL)-8, cyclooxygenase (COX)-2, and matrix metalloproteinase (MMP)-9 were examined in vitro. The effect of DHA on antiangiogenic activity in pancreatic cancer was also assessed using BxPC-3 xenografts subcutaneously established in BALB/c nude mice. RESULTS: DHA inhibited cell proliferation and tube formation of HUVECs in a time- and dose-dependent manner and also reduced cell viability in pancreatic cancer cells. DHA significantly inhibited NF-κB DNA-binding activity, so as to tremendously decrease the expression of NF-κB-targeted proangiogenic gene products: VEGF, IL-8, COX-2, and MMP-9 in vitro. In vivo studies, DHA remarkably reduced tumor volume, decreased microvessel density, and down-regulated the expression of NF-κB-related proangiogenic gene products. CONCLUSIONS: Inhibition of NF-κB activation is one of the mechanisms that DHA inhibits angiogenesis in human pancreatic cancer. We also suggest that DHA could be developed as a novel agent against pancreatic cancer.

microRNA expression alteration after arsenic trioxide treatment in HepG-2 cells.

BACKGROUND AND AIM: More and more microRNA (miRNA) are found to be involved in tumor genesis and progress. Arsenic trioxide has been an effective chemotherapeutic drug in cancer therapy for many years. In this study, we aimed to find the miRNA involved in the mechanisms of arsenic trioxide treatment in cancer therapy. METHODS: We detected the expression profile of miRNA by miRNA microarray and quantitative real-time polymerase chain reaction. Cell viability assay, flow cytometry analysis, prediction of miRNA targets, Western blot analysis and luciferase reporter assay were carried out to determine the role of one selected miRNA, namely mir-29a, in affecting the biological behaviors of HepG-2 cells. RESULTS: Among the 677 human miRNA in the microarray, five miRNA were upregulated and four were downregulated in HepG-2 cells treated with arsenic trioxide compared to their controls. If only changes above two folds were considered, four miRNA were identified, namely miR-24, miR-29a, miR-30a and miR-210, which were all upregulated. Among them, miR-29a showed a positive therapeutic effect in liver cancer cells by inhibiting cell growth and inducing cell apoptosis, and PPM1D was confirmed to be the target gene of miR-29a. Furthermore, a synergy effect was detected between miR-29a and arsenic trioxide. CONCLUSIONS: Arsenic trioxide altered miRNA expression profile in HepG-2 cells. Among the altered miRNA, miR-29a seemed to take a role in the mechanism of arsenic trioxide in liver cancer therapy. The synergy effect between miR-29a and arsenic trioxide may offer this drug a new chance in cancer therapy by decreasing its dose and toxic side-effects.

[Protection of CSE/H2S system in hepatic ischemia reperfusion injury in rats].

OBJECTIVE: To study the protective function and pathophysiology of cystathionine gamma-lyase (CSE)/hydrogen sulfide (H(2)S) system in hepatic ischemia-reperfusion injury (HIRI) in rats. METHODS: Wistar rats were randomly distributed into sham group (n = 18), ischemia-reperfusion (IR) group (n = 18), IR + NaHS group (n = 18) and IR + DL-propargylglycine (PAG) group (n = 18). The hepatic IR model was established by Pringle's hepatic vascular occlusion. At each of the indicated time points (1, 3 and 6 hours after IR), the serum levels of H(2)S and the hepatic CSE activity were measured. The serum levels of inflammatory factors, including TNF-α, IL-10 were determined by ELISA methods. The expression of apoptotic protein, TNF-α, in liver tissue was tested by Western blot assay, cell apoptosis was examined by TUNEL and the histological changes were examined in each group. RESULTS: The serum levels of H(2)S and CSE activity were significantly increased in group IR compared with group sham at all indicated time points (P < 0.05). The serum level of inflammatory factors (P < 0.01) and the hepatic expression of TNF-α protein (P < 0.05) were elevated obviously in group IR than that in group sham. Administration of NaHS could reduce the production of inflammatory factors in serum (P < 0.01), inhibit hepatic protein expression of TNF-α (P < 0.05) and attenuate the liver histological scores of IR injury (P < 0.05), whereas PAG aggravated them. CONCLUSION: The endogenous CSE/H(2)S system maybe involved in the pathogenesis of hepatic IR injury, which suggests that CSE/H(2)S system can protect liver from IR injury in rats by intervening in inflammatory reaction, attenuating the injury severity and inhibiting expression of apoptotic protein TNF-α.

[Experimental study of the function and mechanism combining dihydroartemisinin and gemcitabine in treating pancreatic cancer].

OBJECTIVE: To investigate the anti-tumor activity of combined gemcitabine with dihydroartemisinin, and the mechanism of the anti-tumor effect of gemcitabine enhanced by dihydroartemisinin on pancreatic cancer. METHODS: For cultured cells, cell growth was determined by the MTT assay and apoptosis was evaluated by flow cytometry analysis and confocal laser scanning microscope stained with Annexin V-FITC/PI. The nuclear extract for determining NF-kappaB DNA-binding activity was analyzed by EMSA, while nuclear P65 and its downstream gene expression was determined by Western blot assay. BxPC-3 cells were injected subcutaneously into nude mice to establish pancreatic xenograft tumors and the tumor volume was monitored after exposure to agents. TUNEL assay was used to assess tumor cell apoptosis in tumor tissue. RESULTS: After combination of gemcitabine and dihydroartemisinin treatment, the proliferative inhibition rates of pancreatic cancer cells BxPC-3 and Panc-1 reached up to (81.1 +/- 3.9)% and (76.5 +/- 3.3)%, and the apoptosis rates were up to (53.6 +/- 3.8)% and (48.3 +/- 4.3)%, the differences were significantly (P < 0.01) compared with gemcitabine [(24.8 +/- 2.9)% and (21.8 +/- 3.5)%]. All the treatment groups inhibited the growth of pancreatic xenograft tumors in nude mice. The tumor volume and apoptosis index were (262 +/- 37) mm(3) and (50 +/- 4)% respectively in the combined treatment, compared to those of [(384 +/- 56) mm(3) and (25 +/- 3)%] in gemcitabine, the differences were significantly (P < 0.05). EMSA showed that gemcitabine alone obviously enhanced its DNA-binding activity compared to control. However, dihydroartemisinin significantly reduced its DNA-binding activity, so that abrogated the inducing effect of gemcitabine on NF-kappaB activation. Western blot assay indicated that dihydroartemisinin downregulated expression of nuclear P65, and combined treatment not only downregulated the expression of Cyclin D1, Bcl-xL and Bcl-2 while upregulated Bax, thus reduced the Bcl-2/Bax ratio, but also increased the caspase-3 activation, all of which increased apoptosis in both BxPC-3 and Panc-1 cells. CONCLUSION: Dihydroartemisinin significantly abrogated the inducing effect of gemcitabine on NF-kappaB activation and downregulated the expression of NF-kappaB targeted gene products, which may be one possible mechanism by which dihydroartemisinin augments the anti-tumor effect of gemcitabine on pancreatic cancer.

[An experimental study of gemcitabine inducing pancreatic cancer cell apoptosis potentiated by nuclear factor-kappa B P65 siRNA].

OBJECTIVE: To investigate the effect and mechanism of NF-kappaB P65 gene silencing by small interference RNA on the apoptosis of human pancreatic cancer cells induced by gemcitabine in vitro and in vivo. METHODS: Human pancreatic cancer cells (BxPC-3 and PANC-1) were cultured and respectively divided into five groups: blank control group, negative control siRNA group, gemcitabine group, NF-kappaB P65 siRNA group and gemcitabine + P65 siRNA group. The ability of cell proliferation was analyzed by MTT; the expression of NF-kappaB P65 and the apoptosis related proteins were examined by Western blot assay; the apoptosis was evaluated by the flow cytometry and laser scanning confocal microscopy analysis stained with Annexin V-FITC/PI; the DNA binding activity of NF-kappaB was examined by electrophoretic mobility shift assay. BxPC-3 cells were injected subcutaneously into nude mice to establish pancreatic xenograft tumors. The tumor volume was monitored and TUNEL assay was used to assess the apoptosis index in tumor tissue after treatment. RESULTS: At 72 h after transfection, the combination with gemcitabine and p65 siRNA significantly decreased the cell viability index (P < 0.05), and down-regulated the expression of Bcl-2 and procaspase-3 and up-regulated the expression of Bax compared with other groups. The combined treatment significantly increased the rate of apoptosis compared with other groups (P < 0.05). EMSA assay indicated that the DNA binding activity of NF-kappaB significantly decreased in NF-kappaB P65 siRNA group and gemcitabine+P65 siRNA group compared with Control group. The combined therapy inhibited the growth of pancreatic xenograft tumors by apoptosis induction in nude mice (P < 0.01). CONCLUSIONS: The effect of gemcitabine inducing cell apoptosis may be potentiated through inhibiting the DNA binding activity of NF-kappaB and regulating the expression of apoptosis related proteins by NF-kappaB P65 siRNA, which can activate the mitochondria apoptosis pathway in pancreatic cancer in vitro and in vivo.

Dihydroartemisinin inactivates NF-kappaB and potentiates the anti-tumor effect of gemcitabine on pancreatic cancer both in vitro and in vivo.

Gemcitabine is currently the best known chemotherapeutic option available for pancreatic cancer, but the tumor returns de novo with acquired resistance over time, which becomes a major issue for all gemcitabine-related chemotherapies. In this study, for the first time, we demonstrated that dihydroartemisinin (DHA) enhances gemcitabine-induced growth inhibition and apoptosis in both BxPC-3 and PANC-1 cell lines in vitro. The mechanism is at least partially due to DHA deactivates gemcitabine-induced NF-kappaB activation, so as to decrease tremendously the expression of its target gene products, such as c-myc, cyclin D1, Bcl-2, Bcl-xL. In our in vivo studies, gemcibabine also manifested remarkably enhanced anti-tumor effect when combined with DHA, as manifested by significantly increased apoptosis, as well as decreased Ki-67 index, NF-kappaB activity and its related gene products, and predictably, significantly reduced tumor volume. We concluded that inhibition of gemcitabine-induced NF-kappaB activation is one of the mechanisms that DHA dramatically promotes its anti-tumor effect on pancreatic cancer.

[Study on anticancer effect of dihydroartemisinin on pancreatic cancer].

OBJECTIVE: To investigate the anti-tumor activity of dihydroartemisinin in pancreatic cancer in vitro and in vivo. METHODS: For cultured cells, cell growth was determined by the MTT assay and apoptosis was evaluated by flow cytometry analysis stained with Annexin V-FITC/PI. The protein expression in BxPC-3 cells was analyzed by Western blot assay. BxPC-3 cells were injected subcutaneously into nude mice to establish pancreatic xenograft tumors and the tumor volume was monitored after exposure to dihydroartemisinin. Ki-67 staining and TUNEL assay were used to assess tumor cell proliferation and apoptosis in tumor tissue. RESULTS: After treatment by dihydroartemisinin in vitro, the proliferative inhibition rates of pancreatic cancer cells BxPC-3 and AsPC-1 reached up to (76.2 +/- 3.5)% and (79.5 +/- 2.9)%, and the apoptosis rates were up to (55.5 +/- 3.2)% and (40.0 +/- 3.5)%, the differences were significantly (P < 0.01) compared with control [(2.0 +/- 1.3)% and (0.9 +/- 0.4)%]. Dihydroartemisinin inhibited the growth of pancreatic xenograft tumors in nude mice. The proliferation index and apoptosis index were (49.1 +/- 3.9)% and (50.2 +/- 4.4)% respectively in dihydroartemisinin 50 mg/kg treatment group, compared to those of (72.1 +/- 3.3)% and (9.4 +/- 2.9)% in control, the differences were significantly (P < 0.01). Western blot assay indicated that dihydroartemisinin up-regulates expression of proliferation-associated protein p21(WAF1) and down-regulates expression of PCNA, increases expression of apoptosis-associated protein Bax and decreases expression of Bcl-2 and activates caspase-9 in BxPC-3 cells. CONCLUSIONS: Dihydroartemisinin exerts anti-tumor activity in pancreatic cancer both in vitro and in vivo by proliferation inhibition and apoptosis induction. Dihydroartemisinin can be used as a potential anti-tumor drug in pancreatic cancer.