Long non-coding RNA (FALEC) promotes malignant behaviors of gastric cancer cells by regulating miR-203b/PIM3 axis.

Background: Existing research shows that long non-coding RNAs (lncRNAs) have important regulatory effects in gastric cancer (GC). In recent years, focally amplified lncRNA on chromosome 1 (FALEC) has been repeatedly reported to have carcinogenic effects in thyroid carcinoma, colorectal cancer, and endometrial cancer, etc. While the role and mechanism of FALEC during GC tumorigenesis remains unclear. Methods: The levels of FALEC, microRNA-203b (miR-203b), and Recombinant Pim-3 Oncogene (PIM3) were confirmed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Cell autophagy, proliferation, apoptosis, migration, and invasion were estimated using western blot, transmission electron microscopy (TEM), cell counting kit-8 (CCK-8), flow cytometer, and Transwell assays. The interaction between miR-203b and FALEC or PIM3 was verified using a dual-luciferase reporter assay. Moreover, the involvement of miR-203b and PIM3 in the regulatory effects of FALEC on GC was determined with rescue experiments. Results: The results showed that FALEC and PIM3 were highly expressed, while miR-203b was lowly expressed, in GC. FALEC knockdown repressed GC cell proliferation, migration, and invasion, and promoted apoptosis and autophagy in vitro. Meanwhile, FALEC knockdown prevented growth and induced GC autophagy in vivo. This shows that FALEC upregulated PIM3 by sponging miR-203b in GC cells. Besides, FALEC induced the malignant behaviors of GC cells by regulating the miR-203b/PIM3 axis. Conclusions: The FALEC/miR-203b/PIM3 axis might be a promising therapeutic target for therapy in GC patients.

TIP30 overcomes gefitinib resistance by regulating cytoplasmic and nuclear EGFR signaling in non-small-cell lung cancer.

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) (eg, gefitinib) exert potent therapeutic efficacy in non-small-cell lung cancer (NSCLC) harboring EGFR-activating mutations. However, the resistance to EGFR TKIs limits their clinical therapeutic efficacy. TIP30, a newly identified tumor suppressor, appears to be involved in the regulation of cytoplasmic and nuclear EGFR signaling in NSCLC. Our previous study demonstrated that TIP30 regulated EGF-dependent cyclin D1 transcription in human lung adenocarcinoma and suppressed tumorigenesis. In the present study, the involvement of TIP30 in combating gefitinib resistance in NSCLC was determined for the first time in vitro and in vivo. Gain and loss of function studies showed that overexpression of TIP30 effectively sensitized cells to gefitinib in vitro, whereas TIP30 inhibition promoted gefitinib cell resistance. Moreover, TIP30 negatively regulated the activation of the p-AKT and p-MEK signaling pathways in PC9/GR. Importantly, PC9/GR harbored high levels of nuclear EGFR, and overexpression of TIP30 restored irregular EGFR trafficking and degradation from early endosomes to the late endosomes, decreasing the nuclear accumulation of EGFR, which may partly or totally inhibit EGFR-mediated induction of c-Myc transcription. Xenographic tumors induced by overexpression of TIP30 by PC9/GR cells in nude mice were suppressed compared with their original counterparts. Overall, it was revealed that TIP30 overexpression restored gefitinib sensitivity in NSCLC cells and attenuated the cytoplasmic and nuclear EGFR signaling pathways and may be a promising biomarker in gefitinib resistance in NSCLC.

Aspirin inhibits hypoxia-mediated lung cancer cell stemness and exosome function.

BACKGROUND: Epidemiological studies have illustrated that regular aspirin consumption may decrease the risk of non-small cell lung cancer (NSCLC). The present study aims to investigate the mechanism of aspirin-induced inhibition of NSCLC development during hypoxia. METHODS: A549 cells were pre-treated with the vehicle control or aspirin and then subjected to hypoxic culture. Cell viability was monitored by CCK-8 assay, and flow cytometry was performed to detect cell cycle distributions, apoptosis, and proportion of cancer stem cells (CSCs). Flow cytometric cell sorting was used to separate CSCs. Quantitative reverse transcription-polymerase chain reaction and Western blot were used to detect the mRNA and protein levels of stem cell markers and the related signaling molecules. The abundance of prostaglandin E2 was detected by enzyme-linked immunosorbent assay. Exosomes in the cell culture medium were isolated using ExoQuick, and the number of exosomes was quantified by the EXOCET exosome quantification assay kit. Cell migration and angiogenesis were monitored by transwell migration assay and in vitro angiogenesis experiments. RESULTS: Aspirin inhibited cell proliferation and induced G2/M cell cycle arrest in hypoxic A549 cells; it also inhibited hypoxia-enhanced stemness in both A549 and ALDH+ cells. The drug reduced hypoxia-enhanced numbers of exosomes in A549 cells and exerted negative effects on the hypoxia-mediated up-regulation of exosomal HIF-1α/COX-2 and expression of exosomal miR-135b and miR-210. While hypoxic-induced exosomes can promote the proliferation, migration, and angiogenesis of other A549 cells, aspirin can weaken this promotion by reducing the amount of exosome secreted and changing exosome contents. CONCLUSIONS: Aspirin inhibits the hypoxia-induced stemness, hypoxic-mediated exosome release, and malignant paracrine effects of A549 cells.

Apogossypolone induces apoptosis and autophagy in nasopharyngeal carcinoma cells in an in vitro and in vivo study.

Nasopharyngeal carcinoma (NPC) has a high incidence and mortality rate, particularly in Southern China. Apogossypolone (ApoG2) is a novel derivative of gossypol with antitumor activity and less toxicity. The human NPC CNE-2 cell line was studied in the in vitro model; whilst 4 week-old male nude mice (BALB/c-nu) were inoculated subcutaneously with CNE-2 cells, and xenograft tumors were studied in the in vivo model. Graded concentrations of ApoG2 were used in treatment studies. In ApoG2-treated and control in vitro and in vivo tumor cells, cell apoptosis, and autophagy were evaluated and quantified using fluorescent and transmission electron microscopy and flow cytometry. Hoechst-33258 fluorescence staining was used to evaluate apoptosis in treated and non-treated cell culture and xenograft NPC cells. Western blotting was performed on lysed tumor cells using primary antibodies to B-cell lymphoma-2 (Bcl-2), beclin-1, and ß-actin, and flow cytometry results indicated cell apoptosis rates of 3.90±0.34 and 19.52±1.18% in the control and ApoG2-treated cells, respectively (F=485.294, P<0.001). Western blot analysis showed that ApoG2 significantly decreased expression of the Bcl-2 protein in CNE-2 cells, when compared with control cells (F=68.909, P=0.001) and flow cytometry showed cell autophagy rates of 0.92±3.10% of control cells compared with 28.24±7.35% of ApoG2-treated cells (F=31.035, P=0.003). ApoG2 treatment significantly increased beclin-1 protein expression in CNE-2 cells (F=497.906, P<0.001). ApoG2 treatment inhibited NPC xenograft tumor growth by 65.49% (P<0.05). In conclusion, these results support a role for ApoG2 in inhibiting the growth of human NPC cells by inducing apoptosis and autophagy. Future controlled clinical studies could be planned, to define safety, efficacy and dosing regimens for ApoG2 as a potential treatment for patients with NPC.

Laparoscopic versus open surgery for rectal cancer: a meta-analysis of 3-year follow-up outcomes.

PURPOSE: We wished to evaluate the effectiveness of laparoscopic and open surgery for patients with rectum cancer through a meta-analysis. METHODS: We searched PubMed, EMBASE, and Cochrane database until June 30, 2015, to identify eligible studies. Randomized controlled trials comparing laparoscopic with open surgery for rectum cancer were included. Meta-analysis was performed using the search strategy following the requirement of the Cochrane Library Handbook. Three-year overall survival (OS) and disease-free survival (DFS) were the main endpoints. RESULTS: Eight randomized controlled trials comprising 3145 patients matched the selection criteria. Meta-analysis showed no significant difference between laparoscopic and open surgery in 3-year overall survival (OS) and disease-free survival (DFS) (hazard ratio (HR)3-year OS = 0.83, 95 % CI [0.68-1.01]; P = 0.06; HR3-year DFS = 0.89, 95 % CI [0.75,1.05]; P = 0.16). No evidence of publication bias was observed. CONCLUSION: Our meta-analysis supported the notion that based on the 3-year DFS and OS, oncological outcomes are comparable after laparoscopic and open surgery for rectal cancer.

Curcumin enhances the antitumor effect of ABT-737 via activation of the ROS-ASK1-JNK pathway in hepatocellular carcinoma cells.

At present, the therapeutic treatment strategies for patients with hepatocellular carcinoma (HCC) remain unsatisfactory, and novel methods are urgently required to treat this disease. Members of the B cell lymphoma (Bcl)-2 family are anti­apoptotic proteins, which are commonly expressed at high levels in certain HCC tissues and positively correlate with the treatment resistance of patients with HCC. ABT-737, an inhibitor of Bcl-2 anti-apoptotic proteins, has been demonstrated to exhibit potent antitumor effects in several types of tumor, including HCC. However, treatment with ABT-737 alone also activates certain pro-survival signaling pathways, which attenuate the antitumor validity of ABT-737. Curcumin, which is obtained from Curcuma longa, is also an antitumor potentiator in multiple types of cancer. In the present study, the synergistic effect of curcumin and ABT-737 on HCC cells was investigated for the first time, to the best of our knowledge. It was found that curcumin markedly enhanced the antitumor effects of ABT-737 on HepG2 cells, which was partially dependent on the induction of apoptosis, according to western blot analysis and flow cytometric apoptosis analysis. In addition, the sustained activation of the ROS-ASK1-c-Jun N-terminal kinase pathway may be an important mediator of the synergistic effect of curcumin and ABT-737. Collectively, these results indicated that the combination of curcumin and ABT-737 can efficaciously induce the death of HCC cells, and may offer a potential treatment strategy for patients with HCC.

Role of taxane and anthracycline combination regimens in the management of advanced breast cancer: a meta-analysis of randomized trials.

The clinical benefits provided by using combined taxanes and anthracyclines in first-line chemotherapy for metastatic breast carcinoma (MBC) remain uncertain. This meta-analysis compares the benefits of using a combination of anthracyclines along with taxanes versus using single-agent-based chemotherapeutic regimens in the treatment of MBC.Relevant clinical trials as well as abstracts from articles presented at major cancer conferences were searched in various databases including PubMed, Embase, and Cochrane Library. The relevant studies had a primary endpoint of overall survival (OS) and secondary endpoints that included progression-free survival (PFS), time-to-treatment failure (TTF), time to progression (TTP), objective response rate (ORR), disease control rate (DCR), and safety. The hazard ratios of OS, PFS, TTF, and TTP, the odds ratios of ORR and DCR, and the risk ratios (RRs) for grades 1-2 and 3-4 toxicities were extracted from the retrieved studies and analyzed using various statistical methods. Meta-analytic estimates were derived from a random-effect model.Fifteen trials were included in the final meta-analysis, and the results suggest that chemotherapy with combined anthracyclines and taxanes does not significantly improve the OS of MBC patients when compared with the OS achieved using separate taxane or anthracycline-based regimens. Compared with taxane-based regimens, combined taxane along with anthracycline regimens failed to significantly improve TTP, ORR, or DCR, but did significantly improve TTP and ORR when compared with anthracycline-based regimens. Furthermore, both individual taxane-based and anthracycline-based regimens produced fewer toxic reactions compared to combined taxane along with anthracycline regimens. Taxane-based regimens had lower RRs for side effects of neutropenia, infection/febrile neutropenia, nausea, and vomiting, whereas patients receiving anthracycline-based regimens had lower RRs for neutropenia, infection/febrile neutropenia, anorexia, stomatitis/mucosal inflammation, diarrhea, and sensory neuropathy. In contrast, patients receiving taxane-based regimens were at higher RRs for hand-foot syndrome and diarrhea, whereas patients receiving anthracycline-based regimens had higher RRs for nausea and vomiting.A taxane-based treatment regimen may be a better option than a combined taxane/anthracycline regimen for managing patients with advanced breast cancer, as it produces equivalent clinical outcomes and has less toxicity compared to other similar regimens.

Apogossypolone induces autophagy and apoptosis in breast cancer MCF-7 cells in vitro and in vivo.

OBJECTIVE: Apogossypolone (ApoG2), a new derivative of gossypol, is a potent cell-growth inhibitor. ApoG2 has been demonstrated to have superior anti-tumor activity than gossypol in Bcl-2 transgenic mice. The purpose of this study was to investigate the inhibitory effect of ApoG2 on breast cancer cell line MCF-7 in vitro and in vivo, and to investigate its anti-tumor mechanism. METHODS: MCF-7 cell line in culture was treated with ApoG2. The inhibitory effects of ApoG2 on cell growth were measured by MTT and colony-formation assay. The cell apoptotic rate and cell cycle were analyzed by use of flow cytometry (FCM). The ultrastructural changes were observed by transmission electron microscopy. Autophagy was detected by acridine orange staining. Expression of Bcl-2, Bax, and Beclin 1 proteins was measured by western blot analysis. RESULTS: The inhibitory effect of ApoG2 on MCF-7 cell proliferation was dose and time-dependent. The maximum effect was observed when cells were incubated for 72 h with 40 µM ApoG2. ApoG2 at 5 µM also inhibited colony formation. FCM assay indicated that ApoG2 induced cell apoptosis and caused cell arrest in the S phase and G2/M phase. Transmission electron microscopic examination and acridine orange staining showed that ApoG2 induced intracellular autolysosome formation. Furthermore, ApoG2 reduced Bcl-2 expression, and enhanced expression of Bax and Beclin 1. Xenografting of MCF-7 cells in mice can also be inhibited by ApoG2. CONCLUSION: ApoG2, a novel anti-apoptotic Bcl-2 agent, inhibits proliferation of breast cancer cell line MCF-7 by inducing cell apoptosis and autophagy.

Salinomycin inhibits proliferation and induces apoptosis of human nasopharyngeal carcinoma cell in vitro and suppresses tumor growth in vivo.

Salinomycin (Sal) is a polyether ionophore antibiotic that has recently been shown to induce cell death in various human cancer cells. However, whether salinomycin plays a functional role in nasopharyngeal carcinoma (NPC) has not been determined to date. The present study investigated the chemotherapeutic efficacy of salinomycin and its molecular mechanisms of action in NPC cells. Salinomycin efficiently inhibited proliferation and invasion of 3 NPC cell lines (CNE-1, CNE-2, and CNE-2/DDP) and activated a extensive apoptotic process that is accompanied by activation of caspase-3 and caspase-9, and decreased mitochondrial membrane potential. Meanwhile, the protein expression level of the Wnt coreceptor lipoprotein receptor related protein 6 (LRP6) and ß-catenin was down-regulated, which showed that the Wnt/ß-catenin signaling was involved in salinomycin-induced apoptosis of NPC cells. In a nude mouse NPC xenograft model, the anti-tumor effect of salinomycin was associated with the downregulation of ß-catenin expression. The present study demonstrated that salinomycin can effectively inhibit proliferation and invasion, and induce apoptosis of NPC cells in vitro and inhibit tumor growth in vivo, probably via the inhibition of Wnt/ß-catenin signaling, suggesting salinomycin as a potential candidate for the chemotherapy of NPC.

Intrapleural chemo- and hyperthermotherapies for malignant pleural effusion: a randomized prospective study.

OBJECTIVE: The current prospective randomized study was designed to evaluate the safety and efficacy of combined intrapleural cisplatin and OK-432 (picibanil) plus hyperthermotherapy in patients with malignant pleural effusion (MPE). METHODS: A total of 358 patients with MPE due to end-stage malignancies were enrolled and randomly divided into two groups, A and B: the intrapleural combination of cisplatin and OK-432 with hyperthermotherapy (n = 179) or without hyperthermotherapy (n = 179), respectively. Mild toxicities such as nausea, vomiting or anorexia, bone marrow depression, and pyrexia were similar in both groups. RESULT: Patients in Group A (with hyperthermotherapy) showed a significantly higher overall response (93.4%) compared to those in Group B (79.8%, χ(2) = 43.11, p < .05). The median survival time for patients in Group A and Group B were 8.9 and 6.2 months, respectively (p > .05). After treatment, the quality of life scores were significantly increased in both groups as compared to prior treatment (p < .05). CONCLUSION: In conclusion, our study suggests that combined intrapleural cisplatin and OK-432 followed by hyperthermotherapy are more effective in the control of MPE and improve patients' quality of life.

[Endostatin in different administration routes combined with adriamycin chemotherapy in the treatment of liver cancer xenograft in mice].

OBJECTIVE: To study the antiangiogenetic and tumor inhibitory effects of endostatin (Es) by intratumoral versus intravenous administration combined with adriamycin (Adm) for treatment of transplanted tumor in mice. METHODS: Forty mice were subjected to subcutaneous implantation of H22 cells and randomly divided into 4 groups by the body weight when the tumor diameter reached 1 cm, namely the control group (with intratumoral and intravenous injection of normal saline), Es intratumoral group (with intratumoral injection Es and intraperitoneal Adm injection), Es vein group (with intravenous Es injection and intraperitoneal Adm injection), and Adm group (with intratumoral saline injection and intraperitoneal Adm injection). The tumor volumes and tumor inhibition rates were calculated, and the expression of vascular endothelial growth factor (VEGF) and the microvessel density (MVD) of the tumors were examined, with the survival time of the mice also observed. RESULTS: The tumor volume was smaller in Es intratumoral group than in the other groups (P<0.05). The expression of VEGF and M VD in Es intratumoral group was significantly decreased as compared with that in the other groups (P<0.05). The survival time was significantly longer in Es intratumoral group and Es vein group than in the other groups (P<0.05), but showed no significant difference between Es intratumoral group and Es vein group (P>0.05). CONCLUSION: In combination with Adm regimen, Es given intratumoral injection produces better effect than intravenous Es injection against angiogenesis and tumor growth, no significant difference can be found in the survival time between them.

[Effect of monoclonal antibodies against LI-cadherin on the proliferation of human hepatocellular carcinoma cells].

OBJECTIVE: To obtain monoclonal antibodies (mAb) against LI-cadherin and investigate their effects on the proliferation of human hepatocellular carcinoma cells. METHODS: Balb/c mice were immunized with recombinant LI-cadherin, and hybridoma cell lines secreting monoclonal antibodies against LI-cadherin were established with routine cell fusion and subcloning approach. The specificity of these mAbs was determined by enzyme-linked immunosorbent assay (ELISA) and Western blotting. The effect of the mAbs obtained on the growth of HepG2 cells was assessed using inverted microscope and MTT assay. RESULTS: Two hybridoma cell lines (F001 and F002) stably secreting specific mAbs were obtained. Western blot analysis showed that the two antibodies specifically recognized LI-cadherin antigen derived from human eucaryotic cells or tissue. Treatment of the HepG2 cells with the mAbs resulted in reduced viable cell number and changes in the cell morphologies, and the two mAbs inhibited the proliferation of HepG2 cells in a concentration-dependent manner (P<0.05). CONCLUSION: The two specific mAbs obtained can inhibit the proliferation of HepG2 cells in vitro, which facilitates further study of the relationship between LI-cadherin and tumors.

[Effect of KDR recombinant adenovirus containing double suicide gene on the proliferation of human colon adneocarcinoma SW620 cells].

OBJECTIVE: To study the effect of adenovirus (Ad)-mediated fusion gene system driven by the KDR promoter on the proliferation of human colon adenocarcinoma SW620 cells. METHODS: The KDR-expressing SW620 cells and LS174T cells not expressing KDR were both infected with AdEasy-KDR-CDglyTK followed by treatment with the prodrugs 5-FC and/or ganciclovir at different concentrations. The effect of the transfection on the cell proliferation was evaluated. RESULTS: The expression of green fluorescent protein (GFP) was observed in 95% of the infected SW620 and LS174T cells with a multiplicity of infection (MOI) of 100. Significant difference was not founded in the growth of SW620 and LS174T cells with or without the transfection. The infected SW620 cells exhibit high sensitivity to the prodrugs, but the infected LS174T cells did not (P<0.01). The CDglyTK fusion gene produced much stronger killing effect of on the target cells than either of the single suicide genes (P<0.01). CONCLUSION: CDglyTK fusion gene system driven by the KDR promoter selectively kills the KDR-CDglyTK SW620 cells and inhibits the cell proliferation.

[Synthesis and characterization of folic acid-conjugated chitosan nanoparticles as a tumor-targeted drug carrier].

OBJECTIVE: To synthesize and characterize paclitaxel (PTX)-loaded folate-conjugated chitosan (FA-CTS/PTX) nanoparticles and evaluate its cytotoxicity in vitro. METHODS: CTS/PTX and FA-CTS/PTX nanoparticles were prepared using reductive amidation and ionic gelation of chitosan with tripolyphosphate anions (TPP). The particle size was determined by laser scattering and the morphology observed using transmission electron microscopy, and the PTX content in the nanoparticles was determined using ultraviolet spectrophotometer at 227 nm. The in vitro cytotoxicity of the nanoparticles against HeLa cells was evaluated by MTT assay. Fluorescence microscopy was used to observe the HeLa cells incubated with FA-chitosan nanoparticles in the presence or absence of folic acid in the culture medium. RESULTS: PTX loading did not cause adhesion of the FA-CTS nanoparticles, which presented with uniform spherical morphology with an average diameter of 282.8 nm. The loading and encapsulation efficiencies of FA-CTS/PTX were 9.0% and 75.4%, respectively. The FA-CTS nanoparticles showed a greater extent of intracellular uptake in the absence of folic acid, indicating that the cellular uptake of the nanoparticles occurred through endocytosis mediated by the folate receptors. The PTX-loaded FA-CTS nanoparticles exhibited potent cytotoxicity against HeLa cells, an effect 2- to 3-fold stronger than that of PTX-loaded CTS nanoparticles. CONCLUSION: FA-CTS can be a promising drug carrier with high efficiency in condensing drug, good tumor-targeting ability and low cytotoxicity.

[Preparation of long-circulating nolatrexed dihydrochloride liposomes and its antitumor activity].

OBJECTIVE: To prepare long-circulating liposome (LCL) for sustained release of nolatrexed dihydrochloride and evaluate the effect of this preparation against the growth of hepatocarcinoma cells in mice. METHODS: The long-circulating nolatrexed dihydrochloride liposome was prepared by film dispersion-extrusion combined with ammonium sulphate gradient method. Amphipathic polyethylene glycol-distearoyl phosphatidylethanolamine (PEG-DSPE) was added to modify the property of the liposome membrane. The drug entrapment efficiency of the nolatrexed dihydrochloride-containing liposome was determined using UV detector with Sephadex G50. Electron microscopy and laser particle analyzer were employed to determine the size of the nolatrexed dihydrochloride liposome. For in vivo evaluation of the effect of the liposomal preparation, H22 mouse hepatoma carcinoma cells were transplanted subcutaneouly in mice in the axillary region of the right hind limb to induce growth of solid tumors, which were evaluated for tumor weight inhibition rate and tumor volume changes after administration of the LCL preparations. RESULTS: The mean diameter of the long-circulating nolatrexed dihydrochloride liposomes was 109 nm, with an entrapment efficiency of 68.5%. In vivo antitumor experiment showed that both the common liposomal and LCL preparations of nolatrexed dihydrochloride produced antitumor effect in vivo, and the latter had weaker antitumor effect than free and common liposomal preparation of nolatrexed dihydrochloride, but in the long term, the LCL preparation showed stronger antitumor effect with a tumor weight inhibition rate of 41.68%. CONCLUSION: LCL allows sustained release of nolatrexed dihydrochloride in vivo, and may effectively lengthen the relatively short half life of this drug after administration.

Nonvariational time-dependent multiconfiguration self-consistent field equations for electronic dynamics in laser-driven molecules.

A time-dependent multiconfiguration self-consistent field (TDMCSCF) scheme is developed to describe the time-resolved electron dynamics of a laser-driven many-electron atomic or molecular system, starting directly from the time-dependent Schrodinger equation for the system. This nonvariational formulation aims at the full exploitations of concepts, tools, and facilities of existing, well-developed quantum chemical MCSCF codes. The theory uses, in particular, a unitary representation of time-dependent configuration mixings and orbital transformations. Within a short-time, or adiabatic approximation, the TDMCSCF scheme amounts to a second-order split-operator algorithm involving generically the two noncommuting one-electron and two-electron parts of the time-dependent electronic Hamiltonian. We implement the scheme to calculate the laser-induced dynamics of the two-electron H2 molecule described within a minimal basis, and show how electron correlation is affected by the interaction of the molecule with a strong laser field.

[Expression of DNA transcription- and repair-related genes in cisplatin-resistant human ovarian carcinoma cell line COC1/DDP].

OBJECTIVE: To study the molecular mechanism underlying cisplatin resistance in ovarian carcinoma by detecting the expressions of DNA transcription- and repair-related genes in cisplatin-resistant human ovarian carcinoma COC1 cell line. METHODS: The differential expression of DNA transcription- and repair-related genes between the parental COC1 and cisplatin-resistant COC1/DDP cell line was determined using cDNA microarray. RESULTS AND CONCLUSION: Compared with COC1 cells, 143 genes in COC1/DDP cells showed significant differential expression, among which 20 were DNA transcription- and repair-related genes including 13 significantly up-regulated genes and 7 down-regulated ones. Abnormality of DNA transcription and repair might be involved in the development of cisplatin resistance in COC1/DDP cells.

[Expression of glucosylceramide synthase mRNA in vincristine-resistant KBV200 cell line in association with multidrug resistance].

OBJECTIVE: To investigate the relationship between the expression of glucosylceramide synthase (GCS) mRNA in vincristine-resistant KBV(200) human cancer cell line and multidrug resistance (MDR) of the cancer cells. METHODS: Reverse transcriptional polymerase chain reaction (RT-PCR) was employed to analyze the differential expression of GCS mRNA between KBV(200) and KB cell lines and the changes in the mRNA expressions of GCS and mdr1 gene in KBV(200) cells after reversion of MDR. The effects of de-phenyl-z-palmaitoylamino-3-morpholine-1-propanol (DL-PPMP) and verapamil in reversing MDR of the cells were evaluated by MTT assay. RESULTS: KBV(200) cells exhibited significantly increased expressions of GCS and mdr1 gene, whereas mdr1 gene failed to be detected in the parental KB cells. DL-PPMP within the concentrations ranging from 5 to 25 micromol/L could inhibit the expression of GCS gene, with the maximum inhibition achieved at 25 micromol/L. Verapamil at the concentration of 10 micromol/L was already sufficient to induce inhibition of GCS expression in KVB(200) cells, which was more manifest with the concentration of 15 micromol/L. DL-PPMP and verapamil were found to inhibit mdr1 gene expression in KBV(200) cells at the mRNA level, and complete inhibition occurred after a 48-hour DL-PPMP treatment at 25 micromol/L. CONCLUSION: The inhibition of GCS and mdr1 gene expressions is positively correlated with the concentrations of DL-PPMP and verapamil, which can reverse MDR by inhibiting synthesis of GCS and mdr1 gene, indicating the positive correlation between the expression of GCS gene and MDR in KBV(200) cells. GCS gene might play an important role in MDR during tumor progression.

[Morphological observation on NK/LAK cell-mediated lysis of human oral carcinoma cells].

OBJECTIVE: To understand the relation between cytotoxic activity of immunologic effector cells and multidrug resistance of the tumor cells. METHODS: Continuous observation of the morphological changes and MTT colorimetry were employed to evaluate the cytotoxic activity of lymphokine-activated killer (LAK) cells and natural killer (NK) cells against multidrug-resistant (MDR) human oral carcinoma cell line-KBV200 (before and after reversal of MDR) and parental drug-sensitive cell line KB. The morphologic changes of LAK cells and the 3 target cell lines were observed continuously under inverted microscope 3 h after co-culture of LAK cells with one of three target cell lines respectively. The lysis rates of three tumor cell lines in response to co-culture with LAK or NK cells were determined using MTT colorimetry. RESULTS: In comparison with the parental drug-sensitive cell line KB, both KBV200 and its reserved cell line by verapamil (KBVV) showed earlier adherence and greater number of cells lysed by LAK. In MTT colorimetry assay, the cytotoxicity of both LAK and NK cells against the 3 cell lines was associated with the effector-to-target (E/T) cell ratio; the lysis rates of KBV200 and reversed KBV200 cells by verapamil in response to LAK and NK cells were higher than that of KB cells (P<0.05), but KBV200 and KBVV did not significantly differ (P>0.05). At the same E/T ratio, LAK cells possessed stronger cytotoxicity than NK cells against all the tumor cell lines (P<0.05). CONCLUSIONS: Immunologic effector cells possess strong cytotoxic activity against multidrug-resistant cell line KBV200. Modulation of MDR does not decrease the cytotoxic activity of the immunologic effector cells. The results of this study suggest that adoptive cell immunotherapy with immunologic effector cells may be of value in controlling the progress of MDR tumors.