Cytotoxicity In Lung Cancer Research Articles

Development and characterization of a novel pH-Responsive nanocarrier for enhanced quercetin delivery and cytotoxicity in lung cancer

Quercetin (QC) is a potent polyphenol with numerous health benefits, but its use is limited due to its low bioavailability and high toxicity. Accordingly, a pH-responsive nanocarrier was created using chitosan (CS), halloysite nanotubes (HNTs), and graphene quantum dots (GQDs). It was found that LE and EE values of the CS/GQDs nanocomposites were 32.0% and 69.0%, respectively, increasing to 44.25% and 85.5% upon HNTs addition. The QC release study of pH-responsive CS/HNTs/GQDs nanocomposite in buffer environments showed that with the presence of GQDs in the CS/HNTs composite, the release rate increased from 73% and 54% at pH 5.4 and 7.4 to 97.5% and 67%. Examining the release data with kinetic models showed that the data corresponded to the first-order model, which indicates concentration-dependent drug release. In this study, the cytotoxicity of CS/HNT, CS/HNTs/GQDs, and CS/HNTs/GQDs@QC nanocomposites against L929 and A549 lung cell lines was investigated. The results showed that CS/HNTs/GQDs@QC had the highest cytotoxicity and had a more profound effect on A549 cells. The proportion of apoptotic cells in the CS/HNTs/GQDs@QC group was also higher than in the control group, with early and late apoptosis of 74.4% and 5.15%, respectively.

Epigenetic modulation of immune synaptic-cytoskeletal networks potentiates \u03b3\u03b4 T cell-mediated cytotoxicity in lung cancer

γδ T cells are a distinct subgroup of T cells that bridge the innate and adaptive immune system and can attack cancer cells in an MHC-unrestricted manner. Trials of adoptive γδ T cell transfer in solid tumors have had limited success. Here, we show that DNA methyltransferase inhibitors (DNMTis) upregulate surface molecules on cancer cells related to γδ T cell activation using quantitative surface proteomics. DNMTi treatment of human lung cancer potentiates tumor lysis by ex vivo-expanded Vδ1-enriched γδ T cells. Mechanistically, DNMTi enhances immune synapse formation and mediates cytoskeletal reorganization via coordinated alterations of DNA methylation and chromatin accessibility. Genetic depletion of adhesion molecules or pharmacological inhibition of actin polymerization abolishes the potentiating effect of DNMTi. Clinically, the DNMTi-associated cytoskeleton signature stratifies lung cancer patients prognostically. These results support a combinatorial strategy of DNMTis and γδ T cell-based immunotherapy in lung cancer management.

Inhibition of disheveled-2 resensitizes cisplatin-resistant lung cancer cells through down-regulating Wnt/β-catenin signaling

Cisplatin (CDDP) is currently recommended as the front-line chemotherapeutic agent for lung cancer. However, the resistance to cisplatin is widespread in patients with advanced lung cancer, and the molecular mechanism of such resistance remains incompletely understood. Disheveled (DVL), a key mediator of Wnt/β-catenin, has been linked to cancer progression, while the role of DVL in cancer drug resistance is not clear. Here, we found that DVL2 was over-expressed in cisplatin-resistant human lung cancer cells A549/CDDP compared to the parental A549 cells. Inhibition of DVL2 by its inhibitor (3289-8625) or shDVL2 resensitized A549/CDDP cells to cisplatin. In addition, over-expression of DVL2 in A549 cells increased the protein levels of BCRP, MRP4, and Survivin, which are known to be associated with chemoresistance, while inhibition of DVL2 in A549/CDDP cells decreased these protein levels, and reduced the accumulation and nuclear translocation of β-catenin. In addition, shβ-catenin abolished the DVL2-induced the expression of BCRP, MRP4, and Survivin. Furthermore, our data showed that GSK3β/β-catenin signals were aberrantly activated by DVL2, and inactivation of GSK3β reversed the shDVL2-induced down-regulation of β-catenin. Taken together, these results suggested that inhibition of DVL2 can sensitize cisplatin-resistant lung cancer cells through down-regulating Wnt/β-catenin signaling and inhibiting BCRP, MRP4, and Survivin expression. It promises a new strategy to chemosensitize cisplatin-induced cytotoxicity in lung cancer.

Abstract 257: PARP inhibitor induces cytotoxicity in primary lung cancer through caspase induction

Abstract Considering the fact that lung cancer has a high incidental rate among all cancer types, our investigation was aimed to see if PJ34, a PARP inhibitor, could independently exert cytotoxicity in primary lung cancer cells. In the past this PARP inhibitor has been used in combination with other DNA targeted chemotherapeutics or in patients with DNA repair defects (e.g. BRCA mutation), however, based on our published findings we hypothesize that PJ34 can target lung cancer using alternative mechanisms where defects in DNA repair or synthetic lethality are not required. Additionally, we wanted to reveal the specific mechanisms of PARP inhibitor mediated cytotoxicity in lung cancer cells. Anti-cancerous effects of PJ34 were evaluated on six non-small cell lung cancer cell lines developed from surgically resected tissue. Using WST-1 dye and BrdU assay, 30uM (ED50) of PJ34 treatment showed a variable amount of cell survival and DNA synthesis among cultures used herein. Cellular morphological changes in response to the PJ34 treatment were investigated using annexin-V expression, nuclear fragmentation staining, and PARP specific protein in Western blot. Mitochondrial membrane potential changes were measured through JC-1 dye staining and indicated increased stress upon PJ34 treatment. The abundance of Caspase-9 further proves the role of mitochondrial stress in PJ34 treated cells. Immunofluorescent staining for Caspase-3 clearly showed changes towards apoptosis under PJ34 treated vs. untreated conditions. Additionally, a Caspase-3 specific protein band in PJ34 treated cells indicates the possibility of apoptosis through a caspase dependent pathway. Furthermore, lower expressions of PAR in PJ34 treated cells were indicative of PARP inhibition. This study has brought a new paradigm for using PJ34 as a potential therapeutic against lung cancer because of its ability to work regardless of a patient's genetic makeup as well as the possibility of using this group of compounds as independent chemotherapeutic agents. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 257. doi:1538-7445.AM2012-257

Abstract 3222: Metformin enhances cisplatin cytotoxicity of lung cancer through Stat3 pathway

Abstract The antitumorigenic effects of metformin were mostly interpreted as attributing to the activation of LKB1-AMPK pathway and the studies investigating the AMPK-independent mechanism of metformin remained limited. In lung cancer, cisplatin-based chemotherapy remained the first line regimen for advanced lung cancer patients especially those without EGFR mutation. Previous study demonstrated the linkage between IL6-Stat3 autocrine and chemoresistance. In this study, we first showed that lung cancer line S3C (PC14PE6/AS2 cells with expressing plasmids containing constitutively-active Stat3) was more resistant to cisplatin than PC14PE6/AS2 cell. Treating lung cancer cells with Stat3 inhibitor (JSI-124) or metformin combined with cisplatin, the proliferation of cancer cells were inhibited additionally. And metformin inhibited Stat3 phosphorylation in PC14PE6/AS2 and A549 cells. To investigate the upstream mechanism associated Stat3 phosphorylation, we examined the secretion of IL-6 which was inhibited by metformin. And VEGF secretion, representing Stat3 downstream pathway, was inhibited by metformin in vitro and in vivo. Conversely, the secretion of VEGF was not inhibited in S3C cells after metformin treatment. However, using another AMPK activator-AICAR, the enhancement of cisplatin cytotoxicity is not obvious. In contrast to metformin, AICAR induced AMPK phosphorylation but Stat3 phosphorylation was not inhibited. To verify the LKB-AMPK independent effect of metformin on Stat3 phosphorylation, PC14PE6/AS2 cells were transfected with siRNA targeting LKB1 or AMPK. We demonstrated the inhibition of Stat3 phosphorylation of metformin even under the knockdown of LKB1-AMPK pathway. We also found that MTOR downstream signal including P70S6K and 4EBP1 were inhibited by metformin. Though previous study demonstrated MTOR pathway modulated Stat3 pathway, we found P70S6K and 4EBP1 phosphorylation were inhibited after treatment with metformin at 8hr and Stat3 phosphorylation change was detected after 24hr. Using MTOR inhibitor (rapamycin), the Stat3 tyrosine phosphorylation was not inhibited. Finally, we used subcutaneous tumor xenografts to evaluate the effect of combination of metformin with cisplatin in vivo. Body weight, blood sugar, and tumor volume were recorded in four groups including control, metformin, cisplatin, and metformin combined with cisplatin. Body weights and blood sugar were not different between combination treatment group and control group. In combination group, tumor stopped growing at 18th day and the tumor sizes were obvious less than the other three groups. Immunohistochemical staining of ki67 verified the lower proliferation in combination group. Our study demonstrated that metformin, independent of LKB1-AMPK pathway, inhibits Stat3 phosphorylation which contributes the enhancement of cisplatin cytotoxicity in lung cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3222. doi:1538-7445.AM2012-3222

Induction of death receptor 5 and suppression of survivin contribute to sensitization of TRAIL-induced cytotoxicity by quercetin in non-small cell lung cancer cells

The natural flavonoid quercetin has been suggested by epidemiological studies to have preventive activity against lung cancer; however, the mechanism of which has not been well elucidated. In this report, we demonstrate that quercetin significantly enhances tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced cytotoxicity in non-small cell lung cancer (NSCLC) cells. Quercetin increased expression of death receptor (DR) 5, whereas it had no effect on that of other components of the death-inducing signaling complex. Conversely, the expression of survivin was potently inhibited by quercetin. We further determined that Protein Kinase C (PKC) is essential for DR5 induction but is dispensable for suppression of survivin expression. In contrast, the blockage of the serine/threonine kinase Akt activity by quercetin is important for inhibition of survivin expression but not induction of DR5. These results suggest the pathways for regulation of DR5 and survivin expression by quercetin are distinct. Importantly, suppression of survivin-sensitized TRAIL-induced cell death and blockage of DR5 expression suppressed the synergistic cytotoxicity induced by quercetin and TRAIL co-treatment. On the whole, our data show that quercetin sensitizes TRAIL-induced cytotoxicity in lung cancer cells through two independent pathways: induction of DR5 and suppression of survivin expression, which may underlie the mechanism of the lung cancer preventive activity of quercetin. The potentiation of TRAIL-induced NSCLC cell death could be implicated in lung cancer therapy and prevention.

Heterogeneous response patterns of alveolar macrophages from patients with lung cancer by stimulation with interferon-gamma.

Macrophages are considered to play an important role in the host defense against malignant tumors. In this study, cytotoxic activity of alveolar macrophages (AM) derived from 32 patients with lung cancer was investigated. AM were aseptically obtained by lavage from resected lung and subsequently tested for cytolytic activity against QG56, a lung squamous cell line, following treatment with recombinant interferon-gamma (IFN-gamma). In seven patients (21.9%), AM showed no cytotoxicity even though AM were incubated with IFN-gamma. In 20 (62.5%), AM showed substantial cytotoxicity in response to IFN-gamma in a dose-dependent manner. In the other five (15.6%), relatively strong cytotoxicity was observed even without preincubation with IFN-gamma. Such a heterogeneous profile of the cytotoxicity of AM might be a reflection of various activated states of AM since the potential of cytotoxicity and that of IL-1 secretion were almost parallel. Both IFN-gamma dependent and -independent cytotoxicity were partially blocked either by anti-tumor necrosis factor-alpha (TNF-alpha) antibody or by the inhibitor of nitric oxide synthesis. However, those activities were completely abrogated by both treatments. Since the supernatant of AM culture exhibited TNF-alpha-mediated but not NO-mediated cytolysis, TNF-alpha could mediate a bystander killing whereas NO acts in close contact with tumor cells. The AM have anti-tumor cytotoxicity in lung cancer although the cytolytic potential is heterogeneous and that the tumor lysis by AM is mediated by both TNF-alpha and NO production.