Killing Of Lung Cancer Cells Research Articles

Minimizing the potential of cancer recurrence and metastasis by the use of graphene oxide nano-flakes released from smart fiducials during image-guided radiation therapy

An increasing number of studies show that cancer stem cells become more invasive and may escape into blood stream and lymph nodes before they have received a lethal dose during radiation therapy. Recently, it has been found that graphene oxide (GO) can selectively inhibit the proliferative expansion of cancer stem cells across multiple tumor types. In this study, we investigate the feasibility of using GO during radiotherapy to synergistically inhibit cancer stem cells, and lower the risk of cancer metastasis and recurrence. We hypothesize that graphene oxide nano-flakes (GONFs) released from newly-designed radiotherapy biomaterials (fiducial) can reach targeted tumor cells within 14–21 days. These are the typical time periods between the implantation of the fiducial and the start of image-guided radiation therapy. To test this hypothesis, the spatial-temporal diffusion of GONFs in soft tissue is investigated as a function of different particle sizes. Toxicity of GONFs to normal (HUVEC) and cancer (A549) cells has been assessed using the MTT assay. In addition, the survival fraction of A549 cells treated with GONFs is determined via clonogenic assay during radiotherapy. The diffusion study shows that only GONFs sizes of 50 and 200 nm could achieve the desired concentration of 50 μg/mL for 2 cm diameter tumor after 14 and 21 days respectively. The clonogenic and the MTT assay confirm the additional benefit of GONFs in killing lung cancer cells during radiotherapy. This work avails ongoing in vivo studies that use GONFs to enhance the treatment outcome for cancer patients during radiation therapy.

Mesoporous Carbon Nanospheres with ZnO Nanolids for Multimodal Therapy of Lung Cancer.

To improve therapeutic efficacy, we designed novel poly(ethylene glycol) (PEG)-modified oxidized mesoporous carbon nanospheres (OMCNPs) that were loaded with the therapeutic drug doxorubicin (DOX) and targeted with ligand hyaluronic acid (HA) to kill lung cancer cells. ZnO quantum dots (ZnO QDs) were introduced not only to cap OMCNP-based carriers but also to chelate with DOX, which exhibited a high drug-loading capacity. Upon cellular uptake, the pH-sensitive ZnO lids dissolved to Zn2+ in tumor cells, resulting in dissociation of the Zn2+-DOX complex and controlled release of DOX. Moreover, the novel OMCNP-based system could generate hyperthermia and facilitate the release of loaded DOX with near-infrared (NIR) irradiation. The combined chemo-/photothermal-targeted therapy exhibited significant advantages superior to single chemotherapy or photothermal therapy. This technology provided an excellent lung cancer cell-targeted drug delivery system, integrating chemotherapy with photothermal therapy. This chemo-/photothermal therapy effectively improved the therapeutic efficacy with lower adverse effects to normal tissues.

Rocaglamide enhances NK cell-mediated killing of non-small cell lung cancer cells by inhibiting autophagy

ABSTRACTTargeting macroautophagy/autophagy is a novel strategy in cancer immunotherapy. In the present study, we showed that the natural product rocaglamide (RocA) enhanced natural killer (NK) cell-mediated lysis of non-small cell lung cancer (NSCLC) cells in vitro and tumor regression in vivo. Moreover, this effect was not related to the NK cell recognition of target cells or expressions of death receptors. Instead, RocA inhibited autophagy and restored the level of NK cell-derived GZMB (granzyme B) in NSCLC cells, therefore increasing their susceptibility to NK cell-mediated killing. In addition, we further identified that the target of RocA was ULK1 (unc-51 like autophagy activating kinase 1) that is required for autophagy initiation. Using firefly luciferase containing the 5´ untranslated region of ULK1, we found that RocA inhibited the protein translation of ULK1 in a sequence-specific manner. Taken together, RocA could block autophagic immune resistance to NK cell-mediated killing, and our data suggested that RocA was a promising therapeutic candidate in NK cell-based cancer immunotherapy.

Verteporfin-Loaded Poly(ethylene glycol)-Poly(beta-amino ester)-Poly(ethylene glycol) Triblock Micelles for Cancer Therapy.

Amphiphilic polymers can be used to form micelles to deliver water-insoluble drugs. A biodegradable poly(ethylene glycol) (PEG)-poly(beta-amino ester) (PBAE)-PEG triblock copolymer was developed that is useful for drug delivery. It was shown to successfully encapsulate and pH-dependently release a water-insoluble, small molecule anticancer drug, verteporfin. PEG-PBAE-PEG micelle morphology was also controlled through variations to the hydrophobicity of the central PBAE block of the copolymer in order to evade macrophage uptake. Spherical micelles were 50 nm in diameter, while filamentous micelles were 31 nm in width with an average aspect ratio of 20. When delivered to RAW 264.7 mouse macrophages, filamentous micelles exhibited a 89% drop in cellular uptake percentage and a 5.6-fold drop in normalized geometric mean cellular uptake compared to spherical micelles. This demonstrates the potential of high-aspect-ratio, anisotropically shaped PEG-PBAE-PEG micelles to evade macrophage-mediated clearance. Both spherical and filamentous micelles also showed therapeutic efficacy in human triple-negative breast cancer and small cell lung cancer cells without requiring photodynamic therapy to achieve an anticancer effect. Both spherical and filamentous micelles were more effective in killing lung cancer cells than breast cancer cells at equivalent verteporfin concentrations, while spherical micelles were shown to be more effective than filamentous micelles against both cancer cells. Spherical and filamentous micelles at 5 and 10 μM respective verteporfin concentration resulted in 100% cell killing of lung cancer cells, but both micelles required a higher verteporfin concentration of 20 μM to kill breast cancer cells at the levels of 80% and 50% respectively. This work demonstrates the potential of PEG-PBAE-PEG as a biodegradable, anisotropic drug delivery system as well as the in vitro use of verteporfin-loaded micelles for cancer therapy.

Efficacy and mechanism of steep pulse irreversible electroporation technology on xenograft model of nude mice: a preclinical study

BackgroundSteep pulse therapy can irreversible electrically brackdown of tumor membrance and cause cell death. In previous studies, we investigated the effect of steep pulsed electroporation on the killing of large cell lung cancer cell line L981- in vitro, and determined the best parameters for killing lung cancer cells by steep pulse technology. But the optimal parameters and the mechanisms of steep pulse irreversible electroporation technology on nude mouse tumor model are unclear.MethodsThree settings of steep pulse therapy parameters were applied to the nude mouse model. An in vivo imaging system was employed to observe the effect of different parameters on the mouse model. The pathological changes of the tumor tissue and immunofluorescence data on Caspase-3 protein expression were recorded.ResultsUnder the in vivo imaging system, the steep pulse had an obvious inhibitory effect on the transplanted tumor in the nude mouse model. Pathological tests showed that occurrence of necrosis and apoptosis and expression of Caspase-3 protein in the tumor tissue were increased compared to those in the normal tissue.ConclusionsSteep pulse irreversible electroporation technology showed a promising antitumor effect in the nude mouse tumor model. With splint-type electrode, the best treatment parameters determined for the nude mouse tumor model were voltage amplitude 2000 V/cm, pulse width 100 μs, pulse frequency 1 Hz, pulse number 60, and repeat time 3. Moreover, steep pulse induced coagulative necrosis of tumor tissue by cell apoptosis.

Klebsiella pneumoniae disassembles microtubules and kills vinca alkaloid resistant lung cancer cells

Microtubules play an important role in maintaining cell shape, protein and organellar transport, and cell division. The integrity of the microtubule network is crucial for the viability of mammalian cells. Consequently, the cell has evolved many regulatory mechanisms to ensure the proper regulation of microtubules, especially during the cell cycle. The katanin family of microtubule severing proteins maintain microtubule lengths during interphase. When mitosis occurs, these katanins are recruited to the microtubule organizing centers (MTOCs) to facilitate DNA separation. Previously, we have shown that the microtubules networks in lung epithelia were disassembled by the bacterial pathogen Klebsiella pneumoniae. Because the microtubules were targeted by disease‐causing proteins originating from K. pneumoniae, we hypothesized that K. pneumoniae has devised strategies to manipulate the katanin microtubule severing enzymes to ultimately cause cell cycle arrest. To test this hypothesis, we infected A549 lung cells with K. pneumoniae and immunolocalized the katanin proteins ‐ katanin catalytic subunit A1 protein (KATNA1), katanin catalytic subunit like protein A1 like protein (KATNAL1), katanin regulatory subunit B1 (KATNB1), and katanin regulatory subunit B1 like protein (KATNBL1). In uninfected cells, these proteins immunolocalized to the MTOCs and the cleavage furrow during cell division, but in infected dividing cells, these proteins were absent. This suggested that mitosis was halted. Thus, we examined if these infected cells were still viable and able to proliferate. Using a live/dead staining kit, we found that at this point of the infections, the cells were non‐viable and cell death has occurred. Given that host cells could be killed by the microbes and that microtubules were disassembled during the infections, we investigated whether microtubules could be destroyed in vincristine‐ and vinblastine‐resistant H69AR lung cancer epithelial cells. Microtubule disassembly occurred in these H69AR cells and taken together, we have identified a potent mechanism for destroying the microtubule cytoskeleton and ultimately killing lung cancer cells that are resistant to conventional therapeutics.Support or Funding InformationThis study was funded by SFU institutional funds.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Cytokine-induced killer cells as a feasible adoptive immunotherapy for the treatment of lung cancer

Most of the patients with lung cancer are diagnosed at advanced stage, and they often lose the opportunity of surgical therapy, most of whom fail to reach good prognosis after chemotherapy. Recently, a few clinical studies have confirmed the role of adoptive T-cell transfer in the maintenance therapy of cancer patients. Here, we provided statistical insights into the role of CIKs in advanced lung cancer from three different levels, cell model (in vitro co-culture system), mice model (in situ lung cancer), and clinical research (in lung cancer patients of different progression stages). We optimized the components of supplements and cytokines on activating and expanding CIK cells. Based on this, we explored a new serum-free medium for in vitro activation and expansion of CIK cells. Moreover, we found that activated CIK cells could efficiently kill lung cancer cells in cell-to-cell model in vitro and significantly reduce the tumor growth in mice. For the clinical research, the OS rates of patients received combination of chemotherapy and CIK treatment were significantly improved compared to the OS rates of patients only received chemotherapy. Additionally, CIK therapy represented good toleration in our study. All the results suggested that combination of immunotherapy with traditional therapy will be a feasible and promising method for the treatment of lung cancer.

Ablative Hypofractionated Radiation Therapy Enhances Non-Small Cell Lung Cancer Cell Killing via Preferential Stimulation of Necroptosis In Vitro and In Vivo

Toinvestigate how necroptosis (ie, programmed necrosis) is involved in killing of non-small cell lung cancer (NSCLC) after ablative hypofractionated radiation therapy (HFRT). Deoxyribonucleic acid damage, DNA repair, and the death form of NSCLC cells were assessed after radiation therapy. The overexpression and silencing of receptor-interacting protein kinases 3 (RIP3, a key protein involved activation of necroptosis)-stable NSCLC cell lines were successfully constructed. The form of cell death, the number and area of colonies, and the regulatory proteins of necroptosis were characterized after radiation therapy invitro. Finally, NSCLC xenografts and patient specimens were used to examine involvement of necroptosis after ablative HFRT invivo. Radiation therapy induced expected DNA damage and repair of NSCLC cell lines, but ablative HFRT at ≥10Gy per fraction preferentially stimulated necroptosis in NSCLC cells and xenografts with high RIP3 expression, as characterized by induction and activation of RIP3 and mixed-lineage kinase domain-like protein and release of immune-activating chemokine high-mobility group box 1. In contrast, RNA interference of RIP3 attenuated ablative HFRT-induced necroptosis and activation of its regulatory proteins. Among central early-stage NSCLC patients receiving stereotactic body radiation therapy, high expression of RIP3 was associated with improved local control and progression-free survival (all P<.05). Ablative HFRT at ≥10Gy per fraction enhances killing of NSCLC with high RIP3 expression via preferential stimulation of necroptosis. RIP3 may serve as a useful biomarker to predict favorable response to stereotactic body radiation therapy.

Mitochondrial targeted curcumin exhibits anticancer effects through disruption of mitochondrial redox and modulation of TrxR2 activity

Mitocurcumin is a derivative of curcumin, which has been shown to selectively enter mitochondria. Here we describe the anti-tumor efficacy of mitocurcumin in lung cancer cells and its mechanism of action. Mitocurcumin, showed 25–50 fold higher efficacy in killing lung cancer cells as compared to curcumin as demonstrated by clonogenic assay, flow cytometry and high throughput screening assay. Treatment of lung cancer cells with mitocurcumin significantly decreased the frequency of cancer stem cells. Mitocurcumin increased the mitochondrial reactive oxygen species (ROS), decreased the mitochondrial glutathione levels and induced strand breaks in the mitochondrial DNA. As a result, we observed increased BAX to BCL-2 ratio, cytochrome C release into the cytosol, loss of mitochondrial membrane potential and increased caspase-3 activity suggesting that mitocurcumin activates the intrinsic apoptotic pathway. Docking studies using mitocurcumin revealed that it binds to the active site of the mitochondrial thioredoxin reductase (TrxR2) with high affinity. In corroboration with the above finding, mitocurcumin decreased TrxR activity in cell free as well as the cellular system. The anti-cancer activity of mitocurcumin measured in terms of apoptotic cell death and the decrease in cancer stem cell frequency was accentuated by TrxR2 overexpression. This was due to modulation of TrxR2 activity to NADPH oxidase like activity by mitocurcumin, resulting in higher ROS accumulation and cell death. Thus, our findings reveal mitocurcumin as a potent anticancer agent with better efficacy than curcumin. This study also demonstrates the role of TrxR2 and mitochondrial DNA damage in mitocurcumin mediated killing of cancer cells.

119 - Penta-azamacrocyclic SOD Mimetics Enhance Pharmacological Ascorbate Oxidation and Anticancer effects in an H2O2-dependent Manner

Lung cancer accounts for approximately one-fourth of cancer deaths worldwide; new therapeutic approaches are desperately needed. An emerging adjuvant therapy currently in clinical trials is pharmacological ascorbate (P-AscH‒). The anti-cancer effects of P-AscH‒ are a result of its oxidation, resulting in increased flux and steady-state levels of H2O2 in tumors. P-AscH‒ oxidation can be catalyzed by transition metal ions. P-AscH‒ has been shown to reduce Mn(III)-porphyrin superoxide dismutase (SOD) mimetics, increasing the rate of P-AscH‒ oxidation and enhancing the anti-tumor effect of P-AscH‒. However, the ability of Mn(II)-containing SOD mimetics to enhance the anticancer effects of P-AscH‒ is unknown. The current study shows that Mn(II)-containing penta-azamacrocylic SOD mimetics GC4419 and GC4401 can enhance P-AscH‒ oxidation, as determined by increased oxygen consumption and steady-state concentrations of ascorbate radical in complete cell culture media. These mimetics also enhance the toxicity of P-AscH‒ in H292 and H1299 lung cancer cell lines. This enhanced P-AscH‒-induced lung cancer cell killing was shown to be dependent on the catalytic activity of the SOD mimics and the subsequent generation of H2O2, as determined using conditional overexpression of catalase in H1299 cells. GC4419 combined with P-AscH‒ was also capable of enhancing radiation-induced cancer cell killing in a manner that appears to be greater-than-additive. Since P-AscH‒ and GC4419 are both being tested in individual phase II cancer clinical trials in combination with radiation therapy, these results support the proposal that the combination of GC4419 and P-AscH‒ may provide an effective means by which to significantly enhance radiation responses.

High hydrostatic pressure affects antigenic pool in tumor cells: Implication for dendritic cell-based cancer immunotherapy

High hydrostatic pressure (HHP) can be used to generate dendritic cell (DC)-based active immunotherapy for prostate, lung and ovarian cancer. We showed here that HHP treatment of selected human cancer cell lines leads to a degradation of tumor antigens which depends on the magnitude of HHP applied and on the cancer cell line origin. Whereas prostate or ovarian cell lines displayed little protein antigen degradation with HHP treatment up to 300MPa after 2h, tumor antigens are hardly detected in lung cancer cell line after treatment with HHP 250MPa at the same time. On the other hand, quick reduction of tumor antigen-coding mRNA was observed at HHP 200MPa immediately after treatment in all cell lines tested. To optimize the DC-based active cellular therapy protocol for HHP-sensitive cell lines the immunogenicity of HHP-treated lung cancer cells at 150, 200 and 250MPa was compared. Lung cancer cells treated with HHP 150MPa display characteristics of immunogenic cell death, however cells are not efficiently phagocytosed by DC. Despite induction of the highest number of antigen-specific CD8+ T cells, 150 MPa-treated lung cancer cells survive in high numbers. This excludes their use in DC vaccine manufacturing. HHP of 200MPa treatment of lung cancer cells ensures the optimal ratio of efficient immunogenic killing and delivery of protein antigens in DC. These results represent an important pre-clinical data for generation of immunogenic killed lung cancer cells in ongoing NSCLC Phase I/II clinical trial using DC-based active cellular immunotherapy (DCVAC/LuCa).

Role of NKG2D in cytokine-induced killer cells against lung cancer.

It has been previously demonstrated that cytokine-induced killer (CIK) cells possess potent cytotoxicity against various cancer cells, including lung cancer cells. However, the mechanism by which CIK cells recognize lung cancer cells has not been understood. The interaction between killer cell lectin like receptor K1 (NKG2D) receptor and NKG2D ligands was demonstrated to serve an important role in target cell killing by natural killer cells. The present study investigated whether NKG2D receptor and NKG2D ligand interactions are involved in the CIK-directed killing of lung cancer cells. The expression of MICA and ULBP2 was detected in tumor and healthy tissue samples. The expression of MICA and ULBP2 in tumor tissue samples was higher compared with that in the healthy control tissue. The expression of NKG2D ligands was analyzed in A549 and Q56 cells through reverse transcription-quantitative polymerase chain reaction and flow cytometry. The results demonstrated that the lung cancer cell lines markedly expressed the NKG2D ligands. Furthermore, NKG2D ligand-expressing lung cancer cells were targeted by CIK cells, which was partially blocked by treating CIK cells with an antibody against NKG2D. The data of the current study has demonstrated that the NKG2D-NKG2D ligand interaction serves an essential role in mediating lung cancer cell killing by CIK cells.

Catalase-Modulated Heterogeneous Fenton Reaction for Selective Cancer Cell Eradication: SnFe2O4 Nanocrystals as an Effective Reagent for Treating Lung Cancer Cells.

Heterogeneous Fenton reactions have been proven to be an effective and promising selective cancer cell treatment method. The key working mechanism for this method to achieve the critical therapeutic selectivity however remains unclear. In this study, we proposed and demonstrated for the first time the critical role played by catalase in realizing the therapeutic selectivity for the heterogeneous Fenton reaction-driven cancer cell treatment. The heterogeneous Fenton reaction, with the lattice ferric ions of the solid catalyst capable of converting H2O2 to highly reactive hydroxyl radicals, can effectively eradicate cancer cells. In this study, SnFe2O4 nanocrystals, a recently discovered outstanding heterogeneous Fenton catalyst, were applied for selective killing of lung cancer cells. The SnFe2O4 nanocrystals, internalized into the cancer cells, can effectively convert endogenous H2O2 into highly reactive hydroxyl radicals to invoke an intensive cytotoxic effect on the cancer cells. On the other hand, catalase, present at a significantly higher concentration in normal cells than in cancer cells, remarkably can impede the apoptotic cell death induced by the internalized SnFe2O4 nanocrystals. According to the results obtained from the in vitro cytotoxicity study, the relevant oxidative attacks were effectively suppressed by the presence of normal physiological levels of catalase. The SnFe2O4 nanocrystals were thus proved to effect apoptotic cancer cell death through the heterogeneous Fenton reaction and were benign to cells possessing normal physiological levels of catalase. The catalase modulation of the involved heterogeneous Fenton reaction plays the key role in achieving selective cancer cell eradication for the heterogeneous Fenton reaction-driven cancer cell treatment.

Potential Combinational Anti-Cancer Therapy in Non-Small Cell Lung Cancer with Traditional Chinese Medicine Sun-Bai-Pi Extract and Cisplatin.

Traditional lung cancer treatments involve chemical or radiation therapies after surgical tumor removal; however, these procedures often kill normal cells as well. Recent studies indicate that chemotherapies, when combined with Traditional Chinese Medicines, may offer a new way to treat cancer. In vitro tests measuring the induction of autophagy and/or apoptosis were used to examine the cytotoxicity of SBPE, commonly used for lung inflammation on A549 cell line. The results indicated that intercellular levels of p62 and Atg12 were increased, LC3-I was cleaved into LC3-II, and autophagy was induced with SBPE only. After 24 hours, the apoptotic mechanism was induced. If the Cisplatin was added after cells reached the autophagy state, we observed synergistic effects of the two could achieve sufficient death of lung cancer cells. Therefore, the Cisplatin dosage used to induce apoptosis could be reduced by half, and the amount of time needed to achieve the inhibitory concentration of 50% was also half that of the original. In addition to inducing autophagy within a shortened period of time, the SBPE and chemotherapy drug combination therapy was able to achieve the objective of rapid low-dosage cancer cell elimination. Besides, SBPE was applied with Gemcitabine or Paclitaxel, and found that the combination treatment indeed achieve improved lung cancer cell killing effects. However, SBPE may also be less toxic to normal cells.

Hyaluronic Acid-Modified Multifunctional Q-Graphene for Targeted Killing of Drug-Resistant Lung Cancer Cells.

Considering the urgent need to explore multifunctional drug delivery system for overcoming multidrug resistance, we prepared a new nanocarbon material Q-Graphene as a nanocarrier for killing drug-resistant lung cancer cells. Attributing to the introduction of hyaluronic acid and rhodamine B isothiocyanate (RBITC), the Q-Graphene-based drug delivery system was endowed with dual function of targeted drug delivery and fluorescence imaging. Additionally, doxorubicin (DOX) as a model drug was loaded on the surface of Q-Graphene via π-π stacking. Interestingly, the fluorescence of DOX was quenched by Q-Graphene due to its strong electron-accepting capability, and a significant recovery of fluorescence was observed, while DOX was released from Q-Graphene. Because of the RBITC labeling and the effect of fluorescence quenching/restoring of Q-Graphene, the uptake of nanoparticles and intracellular DOX release can be tracked. Overall, a highly promising multifunctional nanoplatform was developed for tracking and monitoring targeted drug delivery for efficiently killing drug-resistant cancer cells.

Synthesis and Characterization of Inhalable Flavonoid Nanoparticle for Lung Cancer Cell Targeting

Current cancer treatments are not adequate to cure cancer disease, as most chemotherapeutic drugs do not differentiate between cancerous and non-cancerous cells; which lead to systemic toxicity and adverse effects. We have developed a promising approach to deliver a potential anti-cancer compound (curcumin) for lung cancer treatment through pulmonary delivery. Three different sizes of curcumin micellar nanoparticles (Cur-NPs) were fabricated and their cytotoxicity effects (proliferation, apoptosis, cell cycle progression) were evaluated against non-small-cell lung cancer, human lung carcinoma (A549) and human lung adenocarcinoma (Calu-3). The in vitro cytotoxicity assay showed that Cur-NPs were more effective to kill lung cancer cells compared to DMSO-solubilised raw curcumin. The potency of the anti-cancer killing activities was size-dependent. Both raw curcumin and Cur-NPs were not toxic to healthy lung cells (BEAS-2B). Smaller Cur-NPs accumulated within nucleus, membrane and cytoplasm. Cur-NPs also induced apoptosis and caused G2/M arrest in both A549 and Calu-3 cell lines. Compared to raw curcumin, Cur-NPs were more effective in suppressing the expression of the inflammatory marker, Interleukin-8 (IL8). The aerosol performance of Cur-NPs was characterized using the next generation impactor (NGI). All Cur-NPs showed promising aerosolization property with mass median aerodynamic diameter (MMAD) and geometric standard deviation (GSD) ranging between 4.8-5.2 and 2.0-2.1, respectively. This study suggests that inhaled curcumin nanoparticles could potentially be used for lung cancer treatment with minimal side effects.

Synergistic killing of human small cell lung cancer cells by the Bcl-2-inositol 1,4,5-trisphosphate receptor disruptor BIRD-2 and the BH3-mimetic ABT-263.

Small cell lung cancer (SCLC) has an annual mortality approaching that of breast and prostate cancer. Although sensitive to initial chemotherapy, SCLC rapidly develops resistance, leading to less effective second-line therapies. SCLC cells often overexpress Bcl-2, which protects cells from apoptosis both by sequestering pro-apoptotic family members and by modulating inositol 1,4,5-trisphosphate receptor (IP3R)-mediated calcium signaling. BH3-mimetic agents such as ABT-263 disrupt the former activity but have limited activity in SCLC patients. Here we report for the first time that Bcl-2-IP3 receptor disruptor-2 (BIRD-2), a decoy peptide that binds to the BH4 domain of Bcl-2 and prevents Bcl-2 interaction with IP3Rs, induces cell death in a wide range of SCLC lines, including ABT-263-resistant lines. BIRD-2-induced death of SCLC cells appears to be a form of caspase-independent apoptosis mediated by calpain activation. By targeting different regions of the Bcl-2 protein and different mechanisms of action, BIRD-2 and ABT-263 induce cell death synergistically. Based on these findings, we propose that targeting the Bcl-2–IP3R interaction be pursued as a novel therapeutic strategy for SCLC, either by developing BIRD-2 itself as a therapeutic agent or by developing small-molecule inhibitors that mimic BIRD-2.

Targeting lung cancer through inhibition of checkpoint kinases.

Inhibitors of checkpoint kinases ATR, Chk1, and Wee1 are currently being tested in preclinical and clinical trials. Here, we review the basic principles behind the use of such inhibitors as anticancer agents, and particularly discuss their potential for treatment of lung cancer. As lung cancer is one of the most deadly cancers, new treatment strategies are highly needed. We discuss how checkpoint kinase inhibition in principle can lead to selective killing of lung cancer cells while sparing the surrounding normal tissues. Several features of lung cancer may potentially be exploited for targeting through inhibition of checkpoint kinases, including mutated p53, low ERCC1 levels, amplified Myc, tumor hypoxia and presence of lung cancer stem cells. Synergistic effects have also been reported between inhibitors of ATR/Chk1/Wee1 and conventional lung cancer treatments, such as gemcitabine, cisplatin, or radiation. Altogether, inhibitors of ATR, Chk1, and Wee1 are emerging as new cancer treatment agents, likely to be useful in lung cancer treatment. However, as lung tumors are very diverse, the inhibitors are unlikely to be effective in all patients, and more work is needed to determine how such inhibitors can be utilized in the most optimal ways.

Inhibition effect of a custom peptide on lung tumors.

Cecropin B is a natural antimicrobial peptide and CB1a is a custom, engineered modification of it. In vitro, CB1a can kill lung cancer cells at concentrations that do not kill normal lung cells. Furthermore, in vitro, CB1a can disrupt cancer cells from adhering together to form tumor-like spheroids. Mice were xenografted with human lung cancer cells; CB1a could significantly inhibit the growth of tumors in this in vivo model. Docetaxel is a drug in present clinical use against lung cancers; it can have serious side effects because its toxicity is not sufficiently limited to cancer cells. In our studies in mice: CB1a is more toxic to cancer cells than docetaxel, but dramatically less toxic to healthy cells.

Amphiphilic block copolymers bearing six-membered ortho ester ring in side chains as potential drug carriers: synthesis, characterization, and in vivo toxicity evaluation

A new type of amphiphilic block copolymers, poly(ethylene glycol)-block-poly(2-methyl-acrylicacid 2-methoxy-5-methyl-[1,3]dioxin-5-ylmethyl ester) (PEG-b-PMME), bearing acid-labile six-membered ortho ester rings in side chains was synthesized by reversible addition–fragmentation chain-transfer polymerization, and the influence of chain length of the hydrophobic PMME block on micelle properties was investigated. The PEG-b-PMME micelles were stable in aqueous buffer at physiological pH with a low critical micelle concentration. Nile Red as a model drug was encapsulated into the micelles to explore the release profiles. The Nile Red-loaded polymeric micelles showed rapid release of Nile Red in weakly acidic environments (pH 5) but slow release under physiological condition (pH 7.4), due to different hydrolysis rate of ortho ester side chains of PEG-b-PMME. The Paclitaxel (PTX)-loaded micelles retained potency in killing lung cancer cells (A549), compared with the free PTX. No obvious toxicity was found in vitro and in vivo after intraperitoneal injection of the micelles, which confirms that the PEG-b-PMME micelles with unique acid-labile characteristic have great potential as nano-scaled carriers for drug delivery.