A549 Lung Cancer Xenograft Model Research Articles

Au4 cluster inhibits human thioredoxin reductase activity via specifically binding of Au to Cys189

Studies have shown that Au triggers tumor cell apoptosis by directly inhibiting human thioredoxin reductase (hTrxR), thus making Au potential drugs for cancer treatment. However, the exact molecular mechanism of Au inhibiting hTrxR has never been demonstrated via experimental and theoretical studies. Here, we synthesized an Au4 cluster coated by an artificial RGD peptide. This gold cluster can bind with hTrxR (KD: ∼1.74 µM) in vitro, and significantly inhibit hTrxR activity in tumor cells. To analyze the underlying mechanism, we established hTrxR-overexpressing tumor cells and fished Au-hTrxR adducts from tumor cells previously treated by Au clusters. Using single-particle cryo-electron microscopy (Cryo-EM) and mass spectra (MS), we found unexpectedly that, Au (I) ion, metabolism of Au cluster, specifically binds to the Cys189 of hTrxR. Molecular dynamic simulation revealed such specific Au-Cys189 binding effectively broke the electron transfer from Sec498 of hTrxR to Cys32 of thioredoxin. This inhibition of hTrxR activity by Au4 cluster induced ROS-regulated tumor cell apoptosis and significantly suppressed tumor growth in an A549 lung cancer xenograft model. In summary, this study revealed the structural mechanism of Au inhibiting hTrxR activity and shed light to the design and application of novel hTrxR-inhibitory anti-tumor nanodrugs.

TCTP protein degradation by targeting mTORC1 and signaling through S6K, Akt, and Plk1 sensitizes lung cancer cells to DNA-damaging drugs

Translationally controlled tumor protein (TCTP) is expressed in many tissues, particularly in human tumors. It plays a role in malignant transformation, apoptosis prevention, and DNA damage repair. The signaling mechanisms underlying TCTP regulation in cancer are only partially understood. Here, we investigated the role of mTORC1 in regulating TCTP protein levels, thereby modulating chemosensitivity, in human lung cancer cells and an A549 lung cancer xenograft model. The inhibition of mTORC1, but not mTORC2, induced ubiquitin/proteasome-dependent TCTP degradation without a decrease in the mRNA level. PLK1 activity was required for TCTP ubiquitination and degradation and for its phosphorylation at Ser46 upon mTORC1 inhibition. Akt phosphorylation and activation was indispensable for rapamycin-induced TCTP degradation and PLK1 activation, and depended on S6K inhibition, but not mTORC2 activation. Furthermore, the minimal dose of rapamycin required to induce TCTP proteolysis enhanced the efficacy of DNA-damaging drugs, such as cisplatin and doxorubicin, through the induction of apoptotic cell death in vitro and in vivo. This synergistic cytotoxicity of these drugs was induced irrespective of the functional status of p53. These results demonstrate a new mechanism of TCTP regulation in which the mTORC1/S6K pathway inhibits a novel Akt/PLK1 signaling axis and thereby induces TCTP protein stabilization and confers resistance to DNA-damaging agents. The results of this study suggest a new therapeutic strategy for enhancing chemosensitivity in lung cancers regardless of the functional status of p53.

The RXR Agonist MSU42011 Is Effective for the Treatment of Preclinical HER2+ Breast Cancer and Kras-Driven Lung Cancer.

Simple SummaryBreast and lung cancers are the most diagnosed cancers in the United States. Despite advances in treatment, over 176,000 deaths are expected in 2021, highlighting the need for new therapies. We evaluated MSU42011, a new RXR receptor activator, in murine models of breast and lung cancer, and this agonist reduced the tumor burden in both models. The tumor microenvironment is composed of numerous immune cells that can inhibit or promote tumor growth. MSU42011 modulated T cells within the tumor, reducing tumor-promoting immune cells and increasing tumor-killing cells. MSU42011 in combination with immunotherapy (anti-PDL1 and anti-PD1 antibodies) also decreased tumor burden when compared with individual treatments in the lung cancer model.(1) Background: Notwithstanding numerous therapeutic advances, 176,000 deaths from breast and lung cancers will occur in the United States in 2021 alone. The tumor microenvironment and its modulation by drugs have gained increasing attention and relevance, especially with the introduction of immunotherapy as a standard of care in clinical practice. Retinoid X receptors (RXRs) are members of the nuclear receptor superfamily and upon ligand binding, function as transcription factors to modulate multiple cell functions. Bexarotene, the only FDA-approved RXR agonist, is still used to treat cutaneous T-cell lymphoma. (2) Methods: To test the immunomodulatory and anti-tumor effects of MSU42011, a new RXR agonist, we used two different immunocompetent murine models (MMTV-Neu mice, a HER2 positive model of breast cancer and the A/J mouse model, in which vinyl carbamate is used to initiate lung tumorigenesis) and an immunodeficient xenograft lung cancer model. (3) Results: Treatment of established tumors in immunocompetent models of HER2-positive breast cancer and Kras-driven lung cancer with MSU42011 significantly decreased the tumor burden and increased the ratio of CD8/CD4, CD25 T cells, which correlates with enhanced anti-tumor efficacy. Moreover, the combination of MSU42011 and immunotherapy (anti-PDL1 and anti-PD1 antibodies) significantly (p < 0.05) reduced tumor size vs. individual treatments. However, MSU42011 was ineffective in an athymic human A549 lung cancer xenograft model, supporting an immunomodulatory mechanism of action. (4) Conclusions: Collectively, these data suggest that the RXR agonist MSU42011 can be used to modulate the tumor microenvironment in breast and lung cancer.

Suppression of c-Met-Overexpressing Tumors by a Novel c-Met/CD3 Bispecific Antibody.

IntroductionOverexpression of c-Met, or hepatocyte growth factor (HGF) receptor, is commonly observed in tumor biopsies and often associated with poor patient survival, which makes HGF/c-Met pathway an attractive molecular target for cancer therapy. A number of antibody-based therapeutic strategies have been explored to block c-Met or HGF in cancers; however, clinical efficacy has been very limited, indicating that blockade of c-Met signal alone is not sufficient. Thus, an alternative approach is to develop an immunotherapy strategy for c-Met-overexpressing cancers. c-Met/CD3 bispecific antibody (BsAb) could bridge CD3-positive T lymphocytes and tumor cells to result in potent tumor cell killing.Materials and MethodsA bispecific antibody, BS001, which binds both c-Met and CD3, was generated using a novel BsAb platform. Western blotting and T cells-mediated killing assays were utilized to evaluate the BsAb’s effects on cell proliferation, survival and signal transduction in tumor cells. Subcutaneous tumor mouse models were used to analyze the in vivo anti-tumor effects of the bispecific antibody and its combination therapy with PD-L1 antibody.ResultsBS001 showed potent T-cell mediated tumor cells killing in vitro. Furthermore, BS001 inhibited phosphorylation of c-Met and downstream signal transduction in tumor cells. In A549 lung cancer xenograft model, BS001 inhibited tumor growth and increased the proportion of activated CD56+ tumor infiltrating lymphocytes. In vivo combination therapy of BS001 with Atezolizumab (an anti-programmed cell death protein1-ligand (PD-L1) antibody) showed more potent tumor inhibition than monotherapies. Similarly, in SKOV3 xenograft model, BS001 showed a significant efficacy in tumor growth inhibition and tumor recurrence was not observed in more than half of mice treated with a combination of BS001 and Pembrolizumab.Conclusionc-Met/CD3 bispecific antibody BS001 exhibited potent anti-tumor activities in vitro and in vivo, which was achieved through two distinguished mechanisms: through antibody-mediated tumor cell killing by T cells and through inhibition of c-Met signal transduction.

Mono-PEGylation of a Thermostable Arginine-Depleting Enzyme for the Treatment of Lung Cancer.

L-arginine (L-Arg) depletion induced by randomly PEGylated arginine deiminase (ADI-PEG20) can treat arginosuccinate synthase (ASS)-negative cancers, and ADI-PEG20 is undergoing phase III clinical trials. Unfortunately, ASS-positive cancers are resistant to ADI-PEG20. Moreover, the yield of ADI production is low because of the formation of inclusion bodies. Here, we report a thermostable arginine-depleting enzyme, Bacillus caldovelox arginase mutant (BCA-M: Ser161->Cys161). An abundant amount of BCA-M was easily obtained via high cell-density fermentation and heat treatment purification. Subsequently, we prepared BCA-M-PEG20, by conjugating a single 20 kDa PEG monomer onto the Cys161 residue via thio-chemistry. Unlike ADI-PEG20, BCA-M-PEG20 significantly inhibited ASS-positive lung cancer cell growth. Pharmacodynamic studies showed that a single intraperitoneal injection (i.p). administration of 250 U/mouse of BCA-M-PEG20 induced low L-Arg level over 168 h. The mono-PEGylation of BCA-M prolonged its elimination half-life from 6.4 to 91.4 h (a 14-fold increase). In an A549 lung cancer xenograft model, a weekly administration of 250 U/mouse of BCA-M-PEG20 suppressed tumor growth significantly. We also observed that BCA-M-PEG20 did not cause any significant safety issue in mouse models. Overall, BCA-M-PEG20 showed excellent results in drug production, potency, and stability. Thereby, it has great potential to become a promising candidate for lung cancer therapy.

Design, synthesis, and biological evaluation of novel trimethoxyindole derivatives derived from natural products

Piperlongumine, a natural alkaloid, is reported to possess various biological activities. In this study, six analogs with indole moiety have been designed and synthesized using scaffold hopping strategy. They exhibited better antitumor activities than the parent piperlongumine without apparent toxicity in normal cells. Among them, 3-chloro-1-(5,6,7-trimethoxy-1-methyl-1H-indole-2-carbonyl)-5,6-dihydropyridin-2(1H)-one showed the best in vitro antitumor activity with the IC50 value improved in 4–8-fold against four cancer cell lines. In an A549 lung cancer xenograft model, it exhibited a tumor growth inhibition of 54.6%, which is much higher than that of parent piperlongumine (38.3%) and comparable to the positive drug doxorubicin (53.3%). The indole–piperlongumine provides a novel lead compound for anticancer drug discovery.

Role of dalteparin sodium on the growth of cancer cells and tumor-associated angiogenesis in A549 human lung cancer cell line and grafted mouse model.

To investigate the effects of dalteparin sodium on the expression of vascular endothelial growth factor (VEGF), VEGF receptor (VEGFR), and hypoxia-inducible factor 1α (HIF-1α) in A549 human lung cancer (LC) cell line and a human A549-grafted nude mouse model. A549 human lung adenocarcinoma cell line was divided into control group, treated using normal saline (NS); and dalteparin sodium groups, receiving 5, 15, 50, and 150 IU/ml of dalteparin sodium, respectively. Human A549-grafted nude mouse was induced through subcutaneous (SC) injection of A549 (5 × 106/0.2 ml) into the right armpit, and randomly assigned into control group (n = 6) receiving intraperitoneal (i.p.) injection of NS, cisplatin (DDP) group (n = 6, 3 mg/kg DDP alone, i.p., for 3 days), low molecular weight heparin (LMWH) group (n = 6) receiving SC injection of 1500 IU/kg dalteparin sodium for 35 days, and DDP plus LMWH group (n = 6, 3 mg/kg DDP, i.p., for 3 days, followed by SC injection of 1500 IU/kg dalteparin sodium for 35 days). Significant difference was noted in the messenger RNA expression of VEGF, VEGFR, and HIF-1α after treating with heparin with a concentration of 15, 50, or 150 IU/ml in the A549 cell line at 24 and 48 h, respectively. In the human A549-grafted nude mouse model, a significant reduction was noted in the expression of VEGF, VEGFR, and HIF-1α in the tumor mass harvested from the mice receiving administration of dalteparin sodium plus DDP. Dalteparin sodium had the inhibitory effects on the growth of human LC A549 cells in vitro and A549 LC xenograft model, which could be enhanced when administrated together with DDP.

Tumor growth affects the metabonomic phenotypes of multiple mouse non-involved organs in an A549 lung cancer xenograft model

The effects of tumorigenesis and tumor growth on the non-involved organs remain poorly understood although many research efforts have already been made for understanding the metabolic phenotypes of various tumors. To better the situation, we systematically analyzed the metabolic phenotypes of multiple non-involved mouse organ tissues (heart, liver, spleen, lung and kidney) in an A549 lung cancer xenograft model at two different tumor-growth stages using the NMR-based metabonomics approaches. We found that tumor growth caused significant metabonomic changes in multiple non-involved organ tissues involving numerous metabolic pathways, including glycolysis, TCA cycle and metabolisms of amino acids, fatty acids, choline and nucleic acids. Amongst these, the common effects are enhanced glycolysis and nucleoside/nucleotide metabolisms. These findings provided essential biochemistry information about the effects of tumor growth on the non-involved organs.

Synergistic effect of KIOM-CRC#BP10A, an ethanol extract of two medicinal herbs, with cisplatin in A549 lung cancer xenograft model

Synergistic effect of KIOM-CRC#BP10A, an ethanol extract of two medicinal herbs, with cisplatin in A549 lung cancer xenograft model

The Anti-Tumor Activity of Succinyl Macrolactin A Is Mediated through the β-Catenin Destruction Complex via the Suppression of Tankyrase and PI3K/Akt.

Accumulated gene mutations in cancer suggest that multi-targeted suppression of affected signaling networks is a promising strategy for cancer treatment. In the present study, we report that 7-O-succinyl macrolactin A (SMA) suppresses tumor growth by stabilizing the β-catenin destruction complex, which was achieved through inhibition of regulatory components associated with the complex. SMA significantly reduced the activities of PI3K/Akt, which corresponded with a decrease in GSK3β phosphorylation, an increase in β-catenin phosphorylation, and a reduction in nuclear β-catenin content in HT29 human colon cancer cells. At the same time, the activity of tankyrase, which inhibits the β-catenin destruction complex by destabilizing the axin level, was suppressed by SMA. Despite the low potency of SMA against tankyrase activity (IC50 of 50.1 μM and 15.5 μM for tankyrase 1 and 2, respectively) compared to XAV939 (IC50 of 11 nM for tankyrase 1), a selective and potent tankyrase inhibitor, SMA had strong inhibitory effects on β-catenin-dependent TCF/LEF1 transcriptional activity (IC50 of 39.8 nM), which were similar to that of XAV939 (IC50 of 28.1 nM). In addition to suppressing the colony forming ability of colon cancer cells in vitro, SMA significantly inhibited tumor growth in CT26 syngenic and HT29 xenograft mouse tumor models. Furthermore, treating mice with SMA in combination with 5-FU in a colon cancer xenograft model or with cisplatin in an A549 lung cancer xenograft model resulted in greater anti-tumor activity than did treatment with the drugs alone. In the xenograft tumor tissues, SMA dose-dependently inhibited nuclear β-catenin along with reductions in GSK3β phosphorylation and increases in axin levels. These results suggest that SMA is a possible candidate as an effective anti-cancer agent alone or in combination with cytotoxic chemotherapeutic drugs, such as 5-FU and cisplatin, and that the mode of action for SMA involves stabilization of the β-catenin destruction complex through inhibition of tankyrase and the PI3K/Akt signaling pathway.

Abstract 5113: Rapid Cancer Imaging By GGT-targeted Fluorescence Probe For Primary Lung Cancer

Abstract Introduction Lung cancer is the leading cause of cancer death in Japan, however, it has been difficult to detect and diagnose precisely lung cancer with a diameter less than 1cm to date. The purpose of this study is to investigate clinical application of novel GGT-targeted fluorescence probe for detecting the primary lung cancer in an intraoperative manner. Methods As a fluorescence probe for γ-glutamyltranspeptidase (GGT), γ-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG) was used. gGlu-HMRG is non-fluorescent, but is converted to a highly fluorescent hydroxymethyl rhodamine green (HMRG) upon reaction with the enzyme, which tends to accumulate in GGT-overexpressing cancer cells. First, we examined GGT activity of lung cancer cell lines, A549, H460, H441, H82 and H226, by applying gGlu-HMRG and evaluating fluorescence intensities by confocal fluorescence microscopy. We also compared mRNA expression level of GGT1 (one of the subtypes of GGT) by qRT-PCR. Further, by transfecting siRNA targeted to GGT1, we investigated the target of gGlu-HMRG. Next we performed in vivo imaging of orthotopic A549 lung cancer xenograft model in nude mouse to confirm the validity of fluorescence imaging. Finally, we carried out ex vivo fluorescence imaging of 73 human lung cancers and normal lung tissues which were surgically resected, and the fluorescence intensities were analyzed by Receiver Operating Characteristics curve. Results A549, H460 and H441 cells with high GGT1 expression could be visualized with high fluorescence intensity after application of gGlu-HMRG within several minutes, whereas H82 and H226 cells with relatively low GGT1 expression could not. We ascertained that the target of gGlu-HMRG was GGT1 by fluorescence imaging and qRT-PCR with lung cancer cell lines transfected with siRNA for GGT1. In lung cancer xenograft model, pleural dissemination, hilar and mediastinal lymph node metastasis and the surface of lung cancer were clearly detected within 15 minutes after topical drip of gGlu-HMRG. We confirm that every fluorescent lesion was adenocarcinoma pathologically. In ex vivo human lung cancer fluorescence imaging, the sensitivity, specificity and accuracy were calculated to be 43.8% (32/73cases), 84.9% (62/73cases) and 64.4% (94/146), respectively. The adenocarcinomas, cancer of female or never smoker were more significantly detected by fluorescence imaging (p&amp;lt;0.05-0.001). Limited to 19 cases of adenocarcinomas, cancer of female and never smoker, sensitivity, specificity, and accuracy were 78.9% (15/19), 73.7% (14/19) and 76.3% (29/38), respectively. Conclusions We suggest that intraoperative application of gGlu-HMRG to detect pleural dissemination, small mediastinal lymph nodal metastasis, or other small foci of the lung cancer cells on surgical margin might be feasible when the cancer cells overexpress GGT. Intraoperative application of fluorescence probe is highly expected in near future. Citation Format: Haruaki Hino, Mitsuaki Kawashima, Tomonori Murayama, Junji Ichinose, Kentaro Kitano, Kazuhiro Nagayama, Jun-ichi Nitadori, Masaki Anraku, Tomohiro Murakawa, Kasue Mizuno, Sayaka Tanaka, Mako Kamiya, Nobuhiro Nishiyama, Kazunori Kataoka, Kohei Miyazono, Yasuteru Urano, Jun Nakajima. Rapid Cancer Imaging By GGT-targeted Fluorescence Probe For Primary Lung Cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5113. doi:10.1158/1538-7445.AM2015-5113

Anticancer activity of koningic acid and semisynthetic derivatives

A screening program aimed at discovering novel anticancer agents based on natural products led to the selection of koningic acid (KA), known as a potent inhibitor of glycolysis. A method was set up to produce this fungal sesquiterpene lactone in large quantities by fermentation, thus allowing (i) an extensive analysis of its anticancer potential in vitro and in vivo and (ii) the semi-synthesis of analogues to delineate structure–activity relationships. KA was characterized as a potent, but non-selective cytotoxic agent, active under both normoxic and hypoxic conditions and inactive in the A549 lung cancer xenograft model. According to our SAR, the acidic group could be replaced to keep bioactivity but an intact epoxide is essential.

Targeting antitumor effect of rhTNF-α fusion protein mediated by matrix metalloproteinase-2.

The aim of this study was to examine the tumor therapy, targeting effects and side effects of tumor-targeting rhTNF-α fusion protein mediated by matrix metalloproteinase-2 in an animal model in order to provide experimental data for future development of drugs. The median lethal dose (LD50) was obtained from acute toxicity experiments. The A549 lung cancer xenograft model was established, and then randomly divided into the saline, standard substance, and low-, middle- and high-dose fusion protein experiment groups. Each group was administered drugs for 18 days. The length and width of the xenografts were measured every three days, after which the xenograft growth curve was drawn. The mice were sacrificed in each group following treatment and the tumor volume and weight were measured. The targeting, effectiveness and toxicity of the transformed fusion protein, and pathological changes of tumor and organ tissues were examined by hematoxylin and eosin (H&E) staining. Additionally, biochemical markers were used to detect damage of various organs after protein processing. Cell apoptosis and angiogenesis were determined using terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling (TUNEL) testing and immunohistochemistry, respectively, in different dose groups. Tumor growth was markedly retarded in the high-dose experimental and standard hTNF-α groups with antitumor rates of 85.91 and 72.25%, respectively, as compared with the control group. Furthermore, the tumor tissue showed obvious apoptosis (the apoptotic index was 78.78 and 66.65%, respectively) and pathological changes in the high-dose experimental and standard hTNF-α groups. Tumor angiogenesis in each fusion protein group was inhibited (P<0.01) and the biochemical markers of various organs were greatly reduced in the high-dose experimental group (P<0.05). This finding indicated that slight toxic effects of fusion proteins were evident for the heart, liver and kidney. The reforming fusion protein can therefore target tumor tissues and efficiently kill tumor cells, with few side effects.

Enhanced antitumor efficacy of vitamin E TPGS-emulsified PLGA nanoparticles for delivery of paclitaxel

Nanoparticles are efficient delivery vehicles for cancer therapy such as paclitaxel (PTX). In this study, we formulated PTX into PLGA polymeric nanoparticles. Vitamin E TPGS was used as an emulsifier to stabilize the nanoparticle formulation. PTX was encapsulated in TPGS-emulsified polymeric nanoparticles (TENPs) by a nanoprecipitation method in ethanol–water system. The resultant PTX-TENPs showed a very uniform particle size (∼100nm) and high drug encapsulation (>80%). The cytotoxicity of PTX-TENPs was examined in A549 lung cancer cell line. Preferential tumor accumulation of TENPs was observed in the A549 lung cancer xenograft model. Tumor growth was significantly inhibited by intravenous injection of PTX-TENPs. Our results suggested that the modified nanoprecipitation method holds great potential for the fabrication of the PTX loaded polymeric nanoparticles. TPGS can be used in the manufacture of polymeric nanoparticles for the controlled release of PTX and other anti-cancer drugs.

Study on inhibitory effect of aqueous extract of Taxus chinensis var. mairei on growth of A549 lung cancer xenografts in nude mice and its mechanism

To study the effect of aqueous extract of Taxus chinensis var. mairei (AETC) on the growth of A549 lung cancer xenografts in nude mice and its mechanism. The A549 lung cancer xenograft model was established, and then randomly divided into the control group, and low, middle and high dose AETC experiment groups. After 24 hours, they were orally administered with normal saline and drugs of the same volume for seven weeks. The length and width of the xenografts were measured every three days, and the xenograft growth curve was drawn. The nude mice were sacrificed after the administration for seven weeks, and their xenografts were collected to cultivate the anti-tumor rate. Real-time PCR and Western-blot were adopted to detect mRNA and protein levels. All of AETC experiment groups showed a significant anti-tumor effect (P < 0.05). Compared with the control group, each experimental group showed notable reduction in EGFR and Survivin mRNA in xenograft tissues (P < 0.05), with no significant change in VEGF mRNA level. The analysis on gray value ratio showed that EGFR mRNA were down-regulated (P < 0.05) in xenograft tissues in all experimental groups, but with no statistical significance in difference, and Survivin and p-EGFR were significantly down-regulated. AETC has not significant effect on angiogenesis, but may have the inhibitory effect on xenograft growth by inhibiting Survivin protein and EGFR phosphorylation.

Efficacy of RNAi targeting of pyruvate kinase M2 combined with cisplatin in a lung cancer model

Pyruvate kinase isoenzyme M2 (PKM2) is a key enzyme in aerobic glycolysis; inhibition of PKM2 leads to the tumor growth inhibition. In this study, the effects of combined treatment with cisplatin (DDP) and a plasmid that expresses a short hairpin RNA (shRNA) targeting PKM2 on the growth of human A549 xenograft lung cancer model were investigated. The expression of PKM2 in A549 cells was determined by immunofluorescence. PKM2 expression levels were evaluated by Western blot analysis. In a human A549 lung cancer xenograft model, the effects of treatment with shRNA, with or without cisplatin, on tumor volume were determined. Apoptosis and cell proliferation status were examined to determine the mechanisms of tumor growth inhibition. Expression of shRNA targeting PKM2 resulted in inhibition of PKM2 expression in A549 cells. In the lung cancer xenograft model, average tumor volume in the group treated with both cisplatin and shRNA was statistically lower than those of other groups (P < 0.05). The levels of apoptotic cells were significantly higher in samples from animals in the combined treatment group than those from untreated animals (P < 0.05). The cell proliferation rate, as determined by counting cells labeled with an anti-phospho-histone H3, a marker for mitosis, was lower in samples from animals treated with both cisplatin and shRNA than in samples from other groups (P < 0.05). Use of RNA interfering (RNAi) targeting PKM2 significantly inhibited tumor growth when combined with cisplatin in a human A549 lung cancer xenograft model. The enhanced antitumor activity of the combined treatment compared to treatment with shRNA alone may result in part from increased induction of apoptosis and augmented inhibition of cancer cell proliferation.

Improved therapeutic effectiveness by combining liposomal honokiol with cisplatin in lung cancer model

BackgroundHonokiol is a major bioactive compound extracted from Magnolia. The present study was designed to determine whether liposomal honokiol has the antitumor activity against human lung cancer as well as potentiates the antitumor activity of cisplatin in A549 lung cancer xenograft model, if so, to examine the possible mechanism in the phenomenon.Methodshuman A549 lung cancer-bearing nude mice were treated with liposomal honokiol, liposomal honokiol plus DDP or with control groups. Apoptotic cells and vessels were evaluated by fluorescent in situ TUNEL assay and by immunohistochemistry with an antibody reactive to CD31 respectively.ResultsThe present study showed that liposomal honokiol alone resulted in effective suppression of the tumor growth, and that the combined treatment with honokiol plus DDP had the enhanced inhibition of the tumor growth and resulted in a significant increase in life span. The more apparent apoptotic cells in the tumors treated with honokiol plus DDP was found in fluorescent in situ TUNEL assay, compared with the treatment with control groups. In addition, the combination of honokiol and DDP apparently reduced the number of vessels by immunolabeling of CD31 in the tissue sections, compared with control groups.ConclusionIn summary, our data suggest that honokiol alone had the antitumor activity against human lung cancer in A549 lung cancer xenograft model, and that the combination of honokiol with DDP can enhance the antitumor activity, and that the enhanced antitumor efficacy in vivo may in part result from the increased induction of the apoptosis and the enhanced inhibition of angiogenesis in the combined treatment. The present findings may be of importance to the further exploration of the potential application of the honokiol alone or the combined approach in the treatment of lung carcinoma.