Rapamycin induces p53-independent apoptosis through the mitochondrial pathway in non-small cell lung cancer cells

Bioprospecting hydroxylated chalcones in in vitro model of ischemia-reoxygenation and probing NOX4 interactions via molecular docking

Ischemia/reperfusion injury (I/R) is a leading cause of acute kidney injury (AKI) in conditions like kidney transplants, cardiac surgeries, and nephrectomy, contributing to high global mortality and morbidity. This study aimed to analyze the protective effects of 2'-hydroxychalcones in treating I/R-induced AKI by targeting key pathological pathways. Considering strong antioxidant action along with other pharmacological roles of chalcone derivatives, six 2'-hydroxychalcones were synthesized via Claisen-Schmidt condensation and analyzed for their protective effects in an I/R induced AKI model using HK-2 cells. Among six 2'-hydroxychalcones, chalcone A4 significantly increased the HK-2 cells viability compared to I/R group. Chalcone A4 reduced the cell death events by reducing generation of cytoplasmic ROS and mitochondrial transmembrane potential. It also increased GSH and SOD activity while reducing TBARS levels, indicating strong antioxidant action. Scanning electron microscope images showed that chalcone A4 reversed I/R-induced morphological changes in HK-2 cells, including apoptotic blebbing and cytoplasmic fragmentation. Furthermore, in silico studies revealed interactions with NADPH oxidase 4, further supporting its protective role in I/R-induced AKI. These results showed that chalcone A4 possess potential protective action against I/R induced cellular damage possibly due to its strong antioxidant action and potential interaction with NOX4 subunit of NADPH oxidase.

Practical immunomodulatory landscape of glioblastoma multiforme (GBM) therapy

Glioblastoma multiforme (GBM) is the most common harmful high-grade brain tumor with high mortality and low survival rate. Importantly, besides routine diagnostic and therapeutic methods, modern and useful practical techniques are urgently needed for this serious malignancy. Correspondingly, the translational medicine focusing on genetic and epigenetic profiles of glioblastoma, as well as the immune framework and brain microenvironment, based on these challenging findings, indicates that key clinical interventions include immunotherapy, such as immunoassay, oncolytic viral therapy, and chimeric antigen receptor T (CAR T) cell therapy, which are of great importance in both diagnosis and therapy. Relatively, vaccine therapy reflects the untapped confidence to enhance GBM outcomes. Ongoing advances in immunotherapy, which utilizes different methods to regenerate or modify the resistant body for cancer therapy, have revealed serious results with many different problems and difficulties for patients. Safe checkpoint inhibitors, adoptive cellular treatment, cellular and peptide antibodies, and other innovations give researchers an endless cluster of instruments to plan profoundly in personalized medicine and the potential for combination techniques. In this way, antibodies that block immune checkpoints, particularly those that target the program death 1 (PD-1)/PD-1 (PD-L1) ligand pathway, have improved prognosis in a wide range of diseases. However, its use in combination with chemotherapy, radiation therapy, or monotherapy is ineffective in treating GBM. The purpose of this review is to provide an up-to-date overview of the translational elements concentrating on the immunotherapeutic field of GBM alongside describing the molecular mechanism involved in GBM and related signaling pathways, presenting both historical perspectives and future directions underlying basic and clinical practice.

p53 modulates kinase inhibitor resistance and lineage plasticity in NF1-related MPNSTs

Malignant peripheral nerve sheath tumors (MPNSTs) are chemotherapy resistant sarcomas that are a leading cause of death in neurofibromatosis type 1 (NF1). Although NF1-related MPNSTs derive from neural crest cell origin, they also exhibit intratumoral heterogeneity. TP53 mutations are associated with significantly decreased survival in MPNSTs, however the mechanisms underlying TP53-mediated therapy responses are unclear in the context of NF1-deficiency. We evaluated the role of two commonly altered genes, MET and TP53, in kinome reprograming and cellular differentiation in preclinical MPNST mouse models. We previously showed that MET amplification occurs early in human MPNST progression and that Trp53 loss abrogated MET-addiction resulting in MET inhibitor resistance. Here we demonstrate a novel mechanism of therapy resistance whereby p53 alters MET stability, localization, and downstream signaling leading to kinome reprogramming and lineage plasticity. Trp53 loss also resulted in a shift from RAS/ERK to AKT signaling and enhanced sensitivity to MEK and mTOR inhibition. In response to MET, MEK and mTOR inhibition, we observed broad and heterogeneous activation of key differentiation genes in Trp53-deficient lines suggesting Trp53 loss also impacts lineage plasticity in MPNSTs. These results demonstrate the mechanisms by which p53 loss alters MET dependency and therapy resistance in MPNSTS through kinome reprogramming and phenotypic flexibility.

Pharmacological, nutraceutical, and nutritional properties of flaxseed (Linum usitatissimum): An insight into its functionality and disease mitigation

Flaxseed (Linum usitatissimum L.) is derived from the flax plant, an annual herb. The primary relevance of flaxseed is in the human nutrition sector, where it is emerging as a significant functional food component due to its high level of active chemicals, which have been linked to health benefits. Flaxseed may be consumed in numerous forms, including milled, oil, and bakery items. The phytochemicals that are present in flaxseed have greatly drawn interest as bioactive molecules beneficial for health. It is naturally enriched with alpha-linolenic acid, omega-3 fatty acid, lignin, secoisolariciresinol diglucoside, and fiber which are physiologically active in the protection of some chronic illnesses such as cancer, diabetes, cardiovascular disease, and cerebrovascular stroke. Furthermore, the benefits of flaxseed eating have been demonstrated in the animal nutrition industry, resulting in healthier food from animal origin. In reality, the fatty acid profile of meat and fat in swine and poultry is directly impacted by the source of fat in the diet. Feeding omega-3-enriched diets with flaxseed will improve the omega-3 content in eggs and meat, enriching the products. The current study focuses on the latest evidence on the chemical makeup of flaxseed and its positive benefits.

BPR0C261, An Analogous of Microtubule Disrupting Agent D-24851 Enhances the Radiosensitivity of Human Non-Small Cell Lung Cancer Cells via p53-Dependent and p53-Independent Pathways

(1) Destabilization of microtubule dynamics is a primary strategy to inhibit fast growing tumor cells. The low cytotoxic derivative of microtubule inhibitor D-24851, named BPR0C261 exhibits antitumor activity via oral administration. In this study, we investigated if BPR0C261 could modulate the radiation response of human non-small cell lung cancer (NSCLC) cells with or without p53 expression. (2) Different doses of BPR0C261 was used to treat human NSCLC A549 (p53+/+) cells and H1299 (p53-/-) cells. The cytotoxicity, radiosensitivity, cell cycle distribution, DNA damage, and protein expression were evaluated using an MTT assay, a colony formation assay, flow cytometry, a comet assay, and an immunoblotting analysis, respectively. (3) BPR0C261 showed a dose-dependent cytotoxicity on A549 cells and H1299 cells with IC₅₀ at 0.38 μM and 0.86 μM, respectively. BPR0C261 also induced maximum G₂/M phase arrest and apoptosis in both cell lines after 24 h of treatment with a dose-dependent manner. The colony formation analysis demonstrated that a combination of low concentration of BPR0C261 and X-rays caused a synergistic radiosensitizing effect on NSCLC cells. Additionally, we found that a low concentration of BPR0C261 was sufficient to induce DNA damage in these cells, and it increased the level of DNA damage induced by a fractionation radiation dose (2 Gy) of conventional radiotherapy. Furthermore, the p53 protein level of A549 cell line was upregulated by BPR0C261. On the other hand, the expression of PTEN tumor suppressor was found to be upregulated in H1299 cells but not in A549 cells under the same treatment. Although radiation could not induce PTEN in H1299 cells, a combination of low concentration of BPR0C261 and radiation could reverse this situation. (4) BPR0C261 exhibits specific anticancer effects on NSCLC cells by the enhancement of DNA damage and radiosensitivity with p53-dependent and p53-independent/PTEN-dependent manners. The combination of radiation and BPR0C261 may provide an important strategy for the improvement of radiotherapeutic treatment.

Aspiletrein A Induces Apoptosis Cell Death via Increasing Reactive Oxygen Species Generation and AMPK Activation in Non-Small-Cell Lung Cancer Cells

Lung cancer remains a leading cause of death in cancer patients, and deregulation of apoptosis is a serious concern in clinical practice, even though therapeutic intervention has been greatly improved. Plants are a versatile source of biologically active compounds for anticancer drug discovery, and aspiletrein A (AA) is a steroidal saponin isolated from Aspidistra letreae that has a potent cytotoxic effect on various cancer cell lines. In this study, we investigated and determined the underlying molecular mechanism by which AA induces apoptosis. AA strongly induced apoptosis in NSCLC cells by mediating ROS generation and thereby activating AMP-activated protein kinase (AMPK) signaling. Consequently, downstream signaling and levels of phosphorylated mTOR and Bcl-2 were significantly decreased. Pretreatment with either an antioxidant, N-acetylcysteine, or an AMPK inhibitor, compound C, could reverse the apoptosis-inducing effect and counteract the effect of AA on the AMPK signaling pathway. Decreased levels of Bcl-2 were due to AA-mediating Bcl-2 degradation via a ROS/AMPK/mTOR axis-dependent proteasomal mechanism. Consistently, the apoptotic-inducing effect of AA was also observed in patient-derived malignant lung cancer cells, and it suppressed an in vitro 3D-tumorigenesis. This study identified the underlying mechanism of AA on lung cancer apoptosis, thereby facilitating potential research and development of this compound for further clinical implications.

The PI3K/Akt/mTOR pathway in lung cancer; oncogenic alterations, therapeutic opportunities, challenges, and a glance at the application of nanoparticles

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Lung cancer is the most common and deadliest human malignancies.

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The alterations of PI3K/Akt/mTOR pathway are related to lung cancer progression.

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PI3K axis regulates proliferation, apoptosis, metastasis, and EMT of lung cancer.

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Agents inhibiting components of PI3K axis diminish lung tumor growth and invasion.

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Low efficacy and off-target toxicity could be improved by nanoparticle application.

Lung cancer is the leading cause of cancer-related mortality worldwide. Although the PI3K/Akt/mTOR signaling pathway has recently been considered as one of the most altered molecular pathways in this malignancy, few articles reviewed the task. In this review, we aim to summarize the original data obtained from international research laboratories on the oncogenic alterations in each component of the PI3K/Akt/mTOR pathway in lung cancer. This review also responds to questions on how aberrant activation in this axis contributes to uncontrolled growth, drug resistance, sustained angiogenesis, as well as tissue invasion and metastatic spread. Besides, we provide a special focus on pharmacologic inhibitors of the PI3K/Akt/mTOR axis, either as monotherapy or in a combined-modal strategy, in the context of lung cancer. Despite promising outcomes achieved by using these agents, however, the presence of drug resistance as well as treatment-related adverse events is the other side of the coin. The last section allocates a general overview of the challenges associated with the inhibitors of the PI3K pathway in lung cancer patients. Finally, we comment on the future research aspects, especially in which nano-based drug delivery strategies might increase the efficacy of the therapy in this malignancy.

Optimization and Pharmacokinetic Evaluation of Synergistic Fenbendazole and Rapamycin Co-Encapsulated in Methoxy Poly(Ethylene Glycol)-b-Poly(Caprolactone) Polymeric Micelles

Purpose

We aimed to develop a nanocarrier formulation incorporating fenbendazole (FEN) and rapamycin (RAPA) with strong efficacy against A549 cancer cells. As FEN and RAPA are poorly soluble in water, it is difficult to apply them clinically in vivo. Therefore, we attempted to resolve this problem by encapsulating these drugs in polymeric micelles.

Methods

We evaluated drug synergy using the combination index (CI) values of various molar ratios of FEN and RAPA. We formed and tested micelles composed of different polymers. Moreover, we conducted cytotoxicity, stability, release, pharmacokinetic, and biodistribution studies to investigate the antitumor effects of FEN/RAPA-loaded mPEG-b-PCL micelles.

Results

We selected mPEG-b-PCL-containing FEN and RAPA at a molar ratio of 1:2 because these particles were consistent in size and had high encapsulation efficiency (EE, %) and drug loading (DL, %) capacity. The in vitro cytotoxicity was assessed for various FEN, RAPA, and combined FEN/RAPA formulations. After long-term exposures, both the solutions and the micelles had similar efficacy against A549 cancer cells. The in vivo pharmacokinetic study revealed that FEN/RAPA-loaded mPEG-b-PCL micelles had a relatively higher area under the plasma concentration–time curve from 0 to 2 h (AUC_{0–2 h}) and 0 to 8 h (AUC_{0–8 h}) and plasma concentration at time zero (C_o) than that of the FEN/RAPA solution. The in vivo biodistribution assay revealed that the IV injection of FEN/RAPA-loaded mPEG-b-PCL micelles resulted in lower pulmonary FEN concentration than the IV injection of the FEN/RAPA solution.

Conclusion

When FEN and RAPA had a 1:2 molar ratio, they showed synergism. Additionally, using data from in vitro cytotoxicity, synergism between a 1:2 molar ratio of FEN and RAPA was observed in the micelle formulation. The FEN/RAPA-loaded mPEG-b-PCL micelle had enhanced bioavailability than the FEN/RAPA solution.

Protein binding studies with human serum albumin, molecular docking and in vitro cytotoxicity studies using HeLa cervical carcinoma cells of Cu(ii)/Zn(ii) complexes containing a carbohydrazone ligand

The interaction of two binuclear mixed ligand Cu(ii) complexes [Cu(o-phen)LCu(OAc)] (1) and [Cu(o-phen)LCu(o-phen)](OAc) (2) (H3L = o-HOC6H4C(H)[double bond, length as m-dash]N-NH-C(OH)[double bond, length as m-dash]N-N[double bond, length as m-dash]C(H)-C6H4OH-o) and a new mononuclear Zn(ii) complex [Zn(HL)(o-phen)(H2O)](OAc)·H2O (3) (H2L = o-HOC6H4-C(H)[double bond, length as m-dash]N-NH-C([double bond, length as m-dash]O)-NH-N[double bond, length as m-dash]C(H)-C6H4OH-o, o-phen = 1,10-phenanthroline, and OAc = CH3COO-) with human serum albumin (HSA) was studied using fluorescence quenching, synchronous and 3D fluorescence measurements and UV-vis spectroscopy. 3D fluorescence studies showed that the HSA structure was altered at the secondary and tertiary levels upon binding with the complexes. This was further supported by the electronic absorption spectral studies of HSA in the absence and presence of the compounds. The average binding distance (r) between HSA and the complexes was obtained by Förster's resonance energy transfer theory. Complex 3 was structurally characterized by X-ray crystallography. Molecular docking studies indicated that all three complexes primarily bind to HSA in subdomain IIA with amino acid residues such as Arg218 and Lys199 which are located at the entrance of Sudlow's site I. The in vitro cytotoxicities of complexes 1-3 against HeLa cells showed promising anticancer activity (IC50 = 3.5, 3.9 and 16.9 μM for 1, 2 and 3, respectively). Live cell time lapse imaging for 1 was done to capture the dynamic behavior of the cells upon treatment with the complex. Cell cycle analysis by flow cytometry with HeLa cells indicated that 1 and 2 induced cell cycle arrest in the G2/M phase while 3 induced arrest in the G0/G1 phase leading to cell death. Compounds 1 and 2 but not 3 induced apoptosis through the mitochondrial pathway as suggested from the relative p53, caspase3 and bcl2 mRNA levels measured by real-time quantitative PCR analysis.

Gemcitabine and Rapamycin Exhibit Additive Effect against Osteosarcoma by Targeting Autophagy and Apoptosis

The overall prognosis for sarcoma-based cancer patients has remained largely unchanged over the past 10 years. Because there is no effective anticancer drug for patients with chemoresistant osteosarcoma (OS), novel approaches are needed to improve the prognosis. Here, we investigated whether rapamycin (Rapa) could enhance the anti-tumor effects of gemcitabine (Gem) in OS. Gem dose-dependently killed the OS cells, but exhibited much lower cytotoxicity on osteoblasts. Treatment with a combination Gem and Rapa was much more effective than that of either single agent with respect to reducing cell viability, cell invasion, cell migration, and vascular endothelial growth factor production in vitro. Moreover, the combination of these agents suppressed tumor growth, angiogenesis, and lung metastasis in allograft and xenograft murine models of OS with minimal adverse effects. Overall, the combination therapy prolonged the overall survival of tumor-bearing mice. Mechanistically, Gem induced apoptosis and increased the levels of cleaved caspases, while Rapa induced autophagy and microtubule-associated protein light chain 3 (LC3)-I/LC3-II expression both in vitro and in vivo. Our findings suggest that chemotherapy using Gem combined with Rapa may be a novel and promising therapeutic approach for the treatment of OS.

The anti-cancer effect of flaxseed lignan derivatives on different acute myeloid leukemia cancer cells

Flaxseeds have been known for their anti-cancerous effects due to the high abundance of lignans released upon ingestion. The most abundant lignan, secoisolariciresinol diglucoside (SDG), is ingested during the dietary intake of flax, and is then metabolized in the gut into two mammalian lignan derivatives, Enterodiol (END) and Enterolactone (ENL). These lignans were previously reported to possess anti-tumor effects against breast, colon, and lung cancer. This study aims to investigate the potential anti-cancerous effect of the flaxseed lignans SDG, END and ENL on acute myeloid leukemia cells (AML) in vitro and to decipher the underlying molecular mechanism. AML cell lines, (KG-1 and Monomac-1) and a normal lymphoblastic cell line were cultured and treated with the purified lignans. ENL was found to be the most promising lignan, as it exhibits a significant selective dose- and time-dependent cytotoxic effect in both AML cell lines, contrary to normal cells. The cytotoxic effects observed were attributed to apoptosis induction, as revealed by an increase in Annexin V staining of AML cells with increasing ENL concentrations. The increase in the percentage of cells in the pre-G phase, in addition to cell death ELISA analysis, validated cellular and DNA fragmentation respectively. Analysis of protein expression using western blots confirmed the activation of the intrinsic apoptotic pathway upon ENL treatment. This was also accompanied by an increase in ROS production intracellularly. In conclusion, this study demonstrates that ENL has promising anti-cancer effects in AML cell lines in vitro, by promoting DNA fragmentation and the intrinsic apoptotic pathway, highlighting the protective health benefits of flax seeds in leukemia.

Rapamycin inhibits AR signaling pathway in prostate cancer by interacting with the FK1 domain of FKBP51

Reactivation of the androgen receptor signaling pathway in the emasculated environment is the main reason for the occurrence of castration-resistant prostate cancer (CRPC). The immunophilin FKBP51, as a co-chaperone protein, together with Hsp90 help the correct folding of AR. Rapamycin is a known small-molecule inhibitor of FKBP51, but its effect on the FKBP51/AR signaling pathway is not clear. In this study, the interaction mechanism between FKBP51 and rapamycin was investigated using steady-state fluorescence quenching, X-ray crystallization, MTT assay, and qRT-PCR. Steady-state fluorescence quenching assay showed that rapamycin could interact with FKBP51. The crystal of the rapamycin-FKBP51 complex indicated that rapamycin occupies the hydrophobic binding pocket of FK1 domain which is vital for AR activity. The residues involving rapamycin binding are mainly hydrophobic and may overlap with the AR interaction site. Further assays showed that rapamycin could inhibit the androgen-dependent growth of human prostate cancer cells by down-regulating the expression levels of AR activated downstream genes. Taken together, our study demonstrates that rapamycin suppresses AR signaling pathway by interfering with the interaction between AR and FKBP51. The results of this study not only can provide useful information about the interaction mechanism between rapamycin and FKBP51, but also can provide new clues for the treatment of prostate cancer and castration-resistant prostate cancer.

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Rapamycin occupies the hydrophobic binding pocket of FK1 domain of FKBP51.

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Rapamycin suppresses the AR signaling pathway by interacting with FKBP51.

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Rapamycin inhibits the growth of prostate cancer cells via the AR signaling pathway.

Effect of Cetuximab and EGFR Small Interfering RNA Combination Treatment in NSCLC Cell Lines with Wild Type EGFR and Use of KRAS as a Possible Biomarker for Treatment Responsiveness

Background

The epidermal growth factor receptor (EGFR) is a therapeutic target for patients with non-small cell lung cancer (NSCLC). Cetuximab is an anti-EGFR monoclonal antibody that inhibits EGFR signaling and proliferation of colorectal cancer and head and neck cancers. Since only few NSCLC patients benefit from cetuximab therapy, we evaluated a novel combination treatment using cetuximab and EGFR small interfering RNA (siRNA) to strongly suppress EGFR signaling and searched for a biomarker in NSCLC cell lines harboring wild-type EGFR.

Methods

Alterations in EGFR and its downstream genes in five NSCLC cell lines (A549, Lu99, 86-2, Sq19 and Ma10) were assessed through sequencing. The protein expression levels of these molecules were assessed through western blotting. The effect of combination treatment was determined through cell proliferation assay, caspase-3/7 assay, invasion assay, and migration assay.

Results

All cell lines were harboring wild-type EGFR, whereas KRAS, PTEN, TP53 and TP53 were mutated in A549 and Lu99; Lu99 and Sq19; Lu99, 86-2, Sq19 and Ma10; and A549, 86-2, and Sq19 cell lines, respectively. PTEN was not expressed in Sq19, and LKB1 was not expressed in both A549 and Sq19. TP53 was not expressed in both A549 and Lu99. The combination of cetuximab and EGFR siRNA significantly suppressed cell proliferation in 86-2, Sq19 and Ma10, which express wild-type KRAS. It induced apoptosis in A549, 86-2 and Ma10 cells, which express wild type PTEN. The combination treatment had no effect either on cell invasion nor migration in all cell lines.

Conclusion

EGFR targeted therapy using the combination of cetuximab and EGFR siRNA is effective in NSCLC cell lines harboring wild-type EGFR. Wild-type KRAS may act as a potential biomarker for response to combination treatment by the induction of apoptosis in cells with wild-type PTEN.

Two Active Compounds from Caesalpinia sappan L. in Combination with Cisplatin Synergistically Induce Apoptosis and Cell Cycle Arrest on WiDr Cells

Purpose: The aim of this study is to observe the synergistic effect of two active compounds of secang, brazilin and brazilein, combined with cisplatin on WiDr colon cancer cells.

Methods: Cytotoxic activities of brazilin (Bi) and brazilein (Be) in single and in combination with cisplatin (Cisp) were examined by MTT assay. Synergistic effect was analyzed by combination index (CI) parameter. Apoptosis and cell cycle profiles were observed by using flow cytometry.

Results: The result of MTT assay showed that IC₅₀ value of brazilin and brazilein on WiDr cancer cells were 41 µM and 52 µM respectively. The combination of ½ IC50 of Bi-Cisp reduced cells viability up to 64% and showed synergistic effect with CI value less than 1 (CI = 0.8). The combinations of ½ IC₅₀ of Be-Cisp also reduced cells viability up to 78% and showed synergistic effect (CI=0.65). Combination of Bi-Cisp and Be-Cisp induced apoptosis higher than the single treatments. Further analysis on the cell cycle progression showed that single treatment of ½ IC₅₀ of Be and Bi induced S-phase and G2/M-phase accumulation, while combination of Be-Cisp and Bi-Cisp enhanced S-phase accumulation.

Conclusion: Both combination of Bi-Cisp and Be-Cisp showed synergistic effect on WiDr cells through induction of apoptosis and halted the cell cycle progression, thus, WiDr cells growth were significantly reduced.

Synergistic activity of sorafenib and betulinic acid against clonogenic activity of non-small cell lung cancer cells

The highly selective multi‐targeted agent sorafenib is an inhibitor of a number of intracellular signaling kinases with anti‐proliferative, anti‐angiogenic and pro‐apoptotic effects in various types of tumors, including human non‐small cell lung cancer (NSCLC). Betulin displays a broad spectrum of biological and pharmacological properties, including anticancer and chemopreventive activity. Combination of drugs with different targets is a logical approach to overcome multilevel cross‐stimulation among key signaling pathways in NSCLC progression. NSCLC cell lines, A549, H358 and A427, with different KRAS mutations, and normal human peripheral blood lymphocyte cells, were treated with sorafenib and betulinic acid alone and in combination. We examined the effect of different combined treatments on viability (MTS test), proliferation and apoptotic susceptibility based on flow cytometry, alterations in signaling pathways by western blotting and colony‐forming ability. The combination of sorafenib with betulinic acid had a strong effect on the induction of apoptosis of different NSCLC cell lines. In addition, this combination was not toxic for human peripheral blood lymphocytes. Combination treatment changed the expression of proteins involved in the mitochondrial apoptosis pathway and induced apoptotic death by caspase activation. Importantly, combination treatment with low drug concentrations tremendously reduced the colony‐forming ability of A549, H358 and A427 cells, as compared to both compounds alone. In this study, we showed that combination therapy with low concentrations of sorafenib and betulinic acid had the capacity to induce high levels of cell death and abolish clonogenic activity in some NSCLC cell lines regardless of KRAS mutations.

Role of Autophagy and Apoptosis in Non-Small-Cell Lung Cancer

Non-small-cell lung cancer (NSCLC) constitutes 85% of all lung cancers, and is the leading cause of cancer-related death worldwide. The poor prognosis and resistance to both radiation and chemotherapy warrant further investigation into the molecular mechanisms of NSCLC and the development of new, more efficacious therapeutics. The processes of autophagy and apoptosis, which induce degradation of proteins and organelles or cell death upon cellular stress, are crucial in the pathophysiology of NSCLC. The close interplay between autophagy and apoptosis through shared signaling pathways complicates our understanding of how NSCLC pathophysiology is regulated. The apoptotic effect of autophagy is controversial as both inhibitory and stimulatory effects have been reported in NSCLC. In addition, crosstalk of proteins regulating both autophagy and apoptosis exists. Here, we review the recent advances of the relationship between autophagy and apoptosis in NSCLC, aiming to provide few insights into the discovery of novel pathogenic factors and the development of new cancer therapeutics.

The effect of adenosine A1 receptor agonist and antagonist on p53 and caspase 3, 8, and 9 expression and apoptosis rate in MCF-7 breast cancer cell line

Adenosine receptor family especially A1 type is expressed in breast cancer cells in which P53 and caspase genes are wild-type. The aim of this study was to investigate the correlation between A1 receptor and either cell apoptosis or proliferation and also to recognize the relationship between this receptor and P53 and the expression of caspases 3, 8 and 9 in MCF-7 cell line. MCF-7 cells were treated intermittently with A1 receptor agonist N6-Cyclopentyladenosine (CPA) and A1 receptor antagonist 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) in different times to measure the expression of p53, caspase 3, 8 and 9 besides apoptosis and survival rate. Our findings indicated that DPCPX significantly induced apoptosis in MCF-7 cells while the cell viability was reduced specially 72 h after the treatment and the expression of p53 gene and caspase expressions was dramatically up-regulated. On the other hand, CPA increased the cell viability and reduced apoptosis in MCF-7 cells. Our results indicated a significant down-regulation in the MCF-7 mRNA expression of p53 and caspases 3, 8 and 9. Furthermore, DPCPX induced p53 and caspase 3, 8 and 9 expressions that consequently promotes the cell apoptosis in MCF-7 cells. Therefore, DPCPX can be considered as an anti-cancer drug.

Tuberous Sclerosis Complex Associated with Vascular Anomalies or Overgrowth

BACKGROUND

Dysregulation of the mammalian target of rapamycin pathway is the underlying pathogenic mechanism in tuberous sclerosis complex (TSC). Other syndromes caused by genetic alterations in this pathway frequently manifest as vascular anomalies or asymmetric overgrowth. Rarely, these features have been documented in TSC.

OBJECTIVE

To collate cases of TSC with vascular anomaly or overgrowth that have been published and to assemble additional recent cases, as this finding has been underreported.

METHODS

TSC cases from three pediatric dermatology referral centers on two continents were reviewed to identify individuals noted to have hemihypertrophy or vascular anomalies.

RESULTS

We report five additional cases of TSC associated with vascular anomalies or overgrowth that contribute to our understanding of some of the pathways and treatments involved in vascular anomalies.

CONCLUSION

Hemihypertrophy and vascular anomalies may be more frequent in the setting of TSC than previously appreciated. A common pathogenetic mechanism may tie these manifestations together.

Differential effects of the two amino acid sensing systems, the GCN2 kinase and the mTOR complex 1, on primary human alloreactive CD4⁺ T-cells

Amino acid deprivation activates general control nonderepressible 2 (GCN2) kinase and inhibits mammalian target of rapamycin (mTOR), affecting the immune response. In this study, the effects of GCN2 kinase activation or mTOR inhibition on human alloreactive CD4+ T-cells were evaluated. The mixed lymphocyte reaction, as a model of alloreactivity, the GCN2 kinase activator, tryptophanol (TRP), and the mTOR complex 1 inhibitor, rapamycin (RAP), were used. Both TRP and RAP suppressed cell proliferation and induced cell apoptosis. These events were p53-independent in the case of RAP, but were accompanied by an increase in p53 levels in the case of TRP. TRP decreased the levels of the Th2 signature transcription factor, GATA-3, as RAP did, yet the latter also decreased the levels of the Th1 and Th17 signature transcription factors, T-bet and RORγt, whereas it increased the levels of the Treg signature transcription factor, FoxP3. Accordingly, TRP decreased the production of interleukin (IL)-4, as RAP did, but RAP also decreased the levels of interferon-γ (IFN-γ) and IL-17. Both TRP and RAP increased the levels of IL-10. As regards hypoxia-inducible factor-1α (HIF-1α), which upregulates the Th17/Treg ratio, its levels were decreased by RAP. TRP increased the HIF-1α levels, which however, remained inactive. In conclusion, our findings indicate that, in primary human alloreactive CD4+ T-cells, the two systems that sense amino acid deprivation affect cell proliferation, apoptosis and differentiation in different ways or through different mechanisms. Both mTOR inhibition and GCN2 kinase activation exert immunosuppressive effects, since they inhibit cell proliferation and induce apoptosis. As regards CD4+ T-cell differentiation, mTOR inhibition exerted a more profound effect, since it suppressed differentiation into the Th1, Th2 and Th17 lineages, while it induced Treg differentiation. On the contrary, the activation of GCN2 kinase suppressed only Th2 differentiation.

Glyoxalase I inhibition induces apoptosis in irradiated MCF-7 cells via a novel mechanism involving Hsp27, p53 and NF-κB

BACKGROUND

Glyoxalase I (GI) is a cellular defence enzyme involved in the detoxification of methylglyoxal (MG), a cytotoxic byproduct of glycolysis, and MG-derived advanced glycation end products (AGEs). Argpyrimidine (AP), one of the major AGEs coming from MG modifications of proteins arginines, is a pro-apoptotic agent. Radiotherapy is an important modality widely used in cancer treatment. Exposure of cells to ionising radiation (IR) results in a number of complex biological responses, including apoptosis. The present study was aimed at investigating whether, and through which mechanism, GI was involved in IR-induced apoptosis.

METHODS

Apoptosis, by TUNEL assay, transcript and protein levels or enzymatic activity, by RT-PCR, western blot and spectrophotometric methods, respectively, were evaluated in irradiated MCF-7 breast cancer cells, also in experiments with appropriate inhibitors or using small interfering RNA.

RESULTS

Ionising radiation induced a dramatic reactive oxygen species (ROS)-mediated inhibition of GI, leading to AP-modified Hsp27 protein accumulation that, in a mechanism involving p53 and NF-κB, triggered an apoptotic mitochondrial pathway. Inhibition of GI occurred at both functional and transcriptional levels, the latter occurring via ERK1/2 MAPK and ERα modulation.

CONCLUSIONS

Glyoxalase I is involved in the IR-induced MCF-7 cell mitochondrial apoptotic pathway via a novel mechanism involving Hsp27, p53 and NF-κB.

Temsirolimus and chloroquine cooperatively exhibit a potent antitumor effect against colorectal cancer cells

PURPOSE

Temsirolimus (TEM) is a novel, water-soluble mammalian target of rapamycin (mTOR) inhibitor that has shown activity against a wide range of cancers in preclinical models, but its efficacy against colorectal cancer (CRC) has not been fully explored.

METHODS

We evaluated the antitumor effect of TEM in CRC cell lines (CaR-1, HT-29, Colon26) in vitro and in vivo. In vitro, cell growth inhibition was assessed using a MTS assay. Apoptosis induction and cell cycle effects were measured using flow cytometry. Modulation of mTOR signaling was measured using immunoblotting. Antitumor activity as a single agent was evaluated in a mouse subcutaneous tumor model of CRC. The effects of adding chloroquine, an autophagy inhibitor, to TEM were evaluated in vitro and in vivo.

RESULTS

In vitro, TEM was effective in inhibiting the growth of two CRC cell lines with highly activated AKT, possibly through the induction of G1 cell cycle arrest via a reduction in cyclin D1 expression, whereas TEM reduced HIF-1α and VEGF in all three cell lines. In a mouse subcutaneous tumor model, TEM inhibited the growth of tumors in all cell lines, not only through direct growth inhibition but also via an anti-angiogenic effect. We also explored the effects of adding chloroquine, an autophagy inhibitor, to TEM. Chloroquine significantly potentiated the antitumor activity of TEM in vitro and in vivo. Moreover, the combination therapy triggered enhanced apoptosis, which corresponded to an increased Bax/Bcl-2 ratio.

CONCLUSIONS

Based on these data, we propose TEM with or without chloroquine as a new treatment option for CRC.

Genome-wide transcriptional analysis of apoptosis-related genes and pathways regulated by H2AX in lung cancer A549 cells

Histone H2AX is a novel tumor suppressor protein and plays an important role in apoptosis of cancer cells. However, the role of H2AX in lung cancer cells is unclear. The detailed mechanism and epigenetic regulation by H2AX remain elusive in cancer cells. We showed that H2AX was involved in apoptosis of lung cancer A549 cells as in other tumor cells. Knockdown of H2AX strongly suppressed apoptosis of A549 cells. We clarified the molecular mechanisms of apoptosis regulated by H2AX based on genome-wide transcriptional analysis. Microarray data analysis demonstrated that H2AX knockdown in A549 cells affected expression of 3,461 genes, including upregulation of 1,435 and downregulation of 2,026. These differentially expressed genes were subjected to bioinformatic analysis for exploring biological processes regulated by H2AX in lung cancer cells. Gene ontology analysis showed that H2AX affected expression of many genes, through which, many important functions including response to stimuli, gene expression, and apoptosis were involved in apoptotic regulation of lung cancer cells. Pathway analysis identified the mitogen-activated protein kinase signaling pathway and apoptosis as the most important pathways targeted by H2AX. Signal transduction pathway networks analysis and chromatin immunoprecipitation assay showed that two core genes, NFKB1 and JUN, were involved in apoptosis regulated by H2AX in lung cancer cells. Taken together, these data provide compelling clues for further exploration of H2AX function in cancer cells.

Interaction of polyacrylic acid coated and non-coated iron oxide nanoparticles with human neutrophils

Iron oxide nanoparticles (ION), with different coatings and sizes, have attracted extensive interest in the last years to be applied in drug delivery, cancer therapy and as contrast agents in imagiologic techniques such as magnetic resonance imaging. However, the safety of these nanoparticles is still not completely established, particularly to host defense systems that are usually recruited for their clearance from the body. In this paper, given the importance of neutrophils in the immune response of the organism to nanoparticles, the effect of polyacrylic acid (PAA)-coated and non-coated ION on human neutrophils was evaluated in vitro, namely their capacity to activate the oxidative burst and to modify their lifespan. The obtained results showed that the studied PAA-coated and non-coated ION triggered neutrophils' oxidative burst in a NADPH oxidase dependent manner, and that PAA-coated ION increased - while non-coated ION prevented - apoptotic signaling and apoptosis. These effects may have important clinical implications in biomedical applications of ION.

mTOR inhibition of cardamonin on antiproliferation of A549 cells is involved in a FKBP12 independent fashion

AIMS

Cardamonin has previously demonstrated that it had an antiproliferative effect on vascular smooth muscle cells by inhibiting the activity of mammalian target of rapamycin (mTOR). The antiproliferative effect and the possible mechanism of combining with mTOR of cardamonin were investigated on A549 cells.

MAIN METHODS

Cell proliferation, cell cycle and apoptosis were measured by methyl thiazolyl tetrazolium (MTT) and flow cytometry, respectively. mTOR and 12 kDa FK506 binding protein (FKBP12) were transfected into A549 cells by Lipofectamine. Western blots were used to examine the mTOR expressions and its activities, and the expressions of 70 kDa ribosomal S6 kinase (p70S6K), FKBP12 and Interleukin-2 (IL-2), respectively.

KEY FINDINGS

Treated with cardamonin, the proliferation of A549 cells was inhibited. Meanwhile, cell cycle was blocked and DNA synthesis was decreased whereas cell apoptosis was promoted, and the activation of mTOR and p70S6K was decreased by cardamonin. Transfected with mTOR or FKBP12, proliferation of A549 cells was increased. Rapamycin had a similar degree of effect on antiproliferation of both transfected cells. However, the antiproliferative effect of cardamonin on mTOR transfected cells was stronger than that on FKBP12 transfected cells. Both rapamycin and cardamonin decreased the phosphorylation of mTOR and p70S6K in two kinds of transfected cells. Cardamonin had no effect on the expression of FKBP12 and IL-2, whereas the expressions were decreased by rapamycin.

SIGNIFICANCE

Cardamonin inhibited proliferation and induced apoptosis of A549 cells via mTOR. It might directly interact with mTOR independently of binding with FKBP12.

Expression of set is downregulated by rapamycin in human colorectal cancer cells

The purpose of this study was to determine the mechanism through which rapamycin treatment affects the expression of the set gene in human colorectal adenocarcinoma cells. The effect of rapamycin treatment on set expression was evaluated by assessing the mRNA and protein expression of set in the SW480 and LoVo human colon carcinoma cell lines following treatment with rapamycin by quantitative polymerase chain reaction (qPCR) and western blot analysis, respectively. Our results demonstrated that the mRNA and protein levels of set were significantly decreased subsequent to rapamycin treatment in the two cell lines, indicating that set expression may be downregulated by rapamycin in human colorectal adenocarcinoma cells. Our findings suggested that the mammalian target of rapamycin signaling pathway may play a role in tumorigenesis through the regulation of the set gene.

Antitumor effects of rapamycin in pancreatic cancer cells by inducing apoptosis and autophagy

Rapamycin (Rapa), an inhibitor of mammalian target of Rapamycin (mTOR), is an immunosuppressive agent that has anti-proliferative effects on some tumors. This study aims to investigate the effects of Rapa suppressing proliferation of pancreatic carcinoma PC-2 cells in vitro and its molecular mechanism involved in antitumor activities. MTT assays showed that the inhibition of proliferation of PC-2 cells in vitro was in a time- and dose-dependent manner. By using transmission electron microscopy, apoptosis bodies and formation of abundant autophagic vacuoles were observed in PC-2 cells after Rapa treatment. Flow cytometry assays also showed Rapa had a positive effect on apoptosis. MDC staining showed that the fluorescent density was higher and the number of MDC-labeled particles in PC-2 cells was greater in the Rapa treatment group than in the control group. RT-PCR revealed that the expression levels of p53, Bax and Beclin 1 were up-regulated in a dose-dependent manner, indicating that Beclin 1 was involved in Rapa induced autophagy and Rapa induced apoptosis as well as p53 up-regulation in PC-2 cells. The results demonstrated that Rapa could effectively inhibit proliferation and induce apoptosis and autophagy in PC-2 cells.