Hypoxia and anaerobic metabolism relate with immunologically cold breast cancer and poor prognosis.

PURPOSE: Hypoxia-Inducible Factor HIF1α and lactate dehydrogenase LDHA drive anaerobic tumor metabolism and define clinical aggressiveness. We investigated their expression in breast cancer and their role in immune response and prognosis of breast cancer. METHODS: Tissue material from 175 breast cancer patients treated in a prospective study were analyzed with immunohistochemistry for HIF1α and LDH5 expression, in parallel with the tumor-infiltrating lymphocyte TIL-density and tertiary lymphoid structure TLS-density. RESULTS: High LDH5 expression was noted in 48/175 tumors, and this was related to HIF1α overexpression (p < 0.0001), triple-negative TNBC histology (p = 0.01), poor disease-specific survival (p < 0.007), metastasis (p < 0.01), and locoregional recurrence (p = 0.03). High HIF1α expression, noted in 39/175 cases, was linked with low steroid receptor expression (p < 0.05), her2 overexpression (p = 0.01), poor survival (p < 0.04), and high metastasis rates (p < 0.004). High TIL-density in the invading tumor front (TILinv) was linked with low LDH5 and HIF expression (p < 0.0001) and better prognosis (p < 0.02). High TIL-density in inner tumor areas (TILinn) was significantly linked with TNBC. Multivariate analysis showed that PgR-status (p = 0.003, HR 2.99, 95% CI 1.4-6.0), TILinv (p = 0.02, HR 2.31, 95% CI 1.1-4.8), LDH5 (p = 0.01, HR 2.43, 95% CI 1.2-5.0), N-stage (p = 0.04, HR 2.42, 95% CI 1.0-5.8), T-stage (p = 0.04, HR 2.31, 95% CI 1.0-5.1), and her2 status (p = 0.05, HR 2.01, 95% CI 1.0-4.2) were independent variables defining death events. CONCLUSION: Overexpression of LDH5, an event directly related to HIF1α overexpression, characterizes a third of breast tumors, which is more frequent in TNBC. Both HIF1α and LDH5 define cold breast cancer microenvironment and poor prognosis. A rational is provided to study further whether metabolic manipulations targeting HIF and LDH5 may enhance the antitumor immune response in breast cancer.

Ectonucleotidase CD73 and CD39 expression in non-small cell lung cancer relates to hypoxia and immunosuppressive pathways.

AIMS: Adenosine triphosphate (ATP) is released at a high concentration in the tumor microenvironment. The overexpression of ectonucleotidases in non-small-cell lung cancer (NSCLC), metabolizing ΑΤP to the immunosuppressive adenosine, is studied. MATERIALS AND METHODS: We examined the expression of the ectonucleotidases CD73 and CD39 in NSCLC in parallel with immunological parameters and markers of hypoxia and anaerobic metabolism. In vitro experiments with A549 and H1299 lung cancer cell lines were also conducted. RESULTS: CD73 and CD39 were not expressed by normal bronchial and alveolar epithelium. In contrast, these were overexpressed by cancer cells, cancer-associated fibroblasts (CAFs), and tumor-infiltrating lymphocytes (TILs). High CD73 cancer cell expression was directly linked with lactate dehydrogenase LDH5 and with hypoxia-inducible factor HIF1α expression by cancer cells. The expression of CD39 by CAFs was directly linked with PD-L1 expression by cancer cells. A significant abundance of FOXP3+ and PD-1+ TILs was noted in tumors with high CD73 and CD39 stroma expression. In in vitro experiments, hypoxia and acidity induced CD73 mRNA and protein levels in cancer cell lines. Exposure of cancer cell lines to adenosine induced the expression of PD-L1 and LDHA mRNA and protein levels. CONCLUSION: Ectonucleotidases are up-regulated in cancer cells, CAFs, and TILs in lung tumors. Such overexpression is linked with regulatory TIL-phenotype and PD-L1 up-regulation by cancer cells. Overexpression of LDH5 is up-regulated by adenosine, creating a vicious cycle, as the high amounts of ATP produced by LDH5-mediated anaerobic glycolysis promote the production of adenosine by a tumor microenvironment rich in ectonucleotidases.

Current trends in cancer immunotherapy: a literature-mining analysis.

Cancer immunotherapy is a rapidly growing field that is completely transforming oncology care. Mining this knowledge base for biomedically important information is becoming increasingly challenging, due to the expanding number of scientific publications, and the dynamic evolution of this subject with time. In this study, we have employed a literature-mining approach that was used to analyze the cancer immunotherapy-related publications listed in PubMed and quantify emerging trends. A total of 93,033 publications published in 5055 journals have been retrieved, and 141 meaningful topics have been identified, which were further classified into eight distinct categories. Statistical analysis indicates a mean annual increase in the number of published papers of approximately 8% in the last 20 years. The research topics that exhibited the highest trends included "immune checkpoint inhibitors," "tumor microenvironment," "HPV vaccination," "CAR T-cells," and "gene mutations/tumor profiling." The top identified cancer types included "lung," "colorectal," and "breast cancer," and a shift in popularity from hematological to solid tumors was observed. As regards clinical research, a transition from early phase clinical trials to randomized control trials was recorded, indicating that the field is entering a more advanced phase of development. Overall, this mining approach provided an unbiased analysis of the cancer immunotherapy literature in a time-conserving and scale-efficient manner.

Ghrelin Levels in Basal Conditions and During Glucose Tolerance Test in Prediabetic and Diabetic Patients.

Ghrelin is associated with glucose homeostasis but its' possible relevance with glucose levels in physiological and pathological conditions has so far been poorly investigated. The aim of the present study was to evaluate circulating ghrelin levels in prediabetic and diabetic patients in basal conditions and in response to oral glucose tolerance test (OGTT). A total of 90 male adults aged 40 - 73 years old were enrolled in our study. Fasting and postprandial plasma ghrelin, insulin and glucose levels were measured at 0, 60, 120 and 180 min following an OGTT in 40 patients with type 2 diabetes mellitus (T2DM), 20 with impaired glucose tolerance (IGT) and 30 controls. Incremental and total area under response curve were determined and calculated for glucose, insulin and ghrelin. Fasting plasma ghrelin concentrations were significantly lower in the T2DM group than IGT and control group patients (p<0.01) but not between healthy subjects and IGT group (p=0.746). In the diabetics' group ghrelin levels showed a statistically significant negative correlation with insulin and a positive correlation with HbA1c and glucose. At all time points after the OGTT ghrelin concentrations were significantly lower in the T2DM group compared to IGT group and controls. Plasma ghrelin concentrations are lower in male diabetic patients at the fasting state and remain lower at all time points after an OGTT while minor differences were found between normal and IGT subjects. Ghrelin might play a role in insulin and glucose metabolism in diabetic patients but not in patients with IGT.

Increased Soluble PD-L1 Levels in the Plasma of Patients with Epithelial Ovarian Cancer Correlate with Plasma Levels of miR34a and miR200.

BACKGROUND: Recently, programmed cell death protein 1 (PD1) blocking and anti-programmed death-ligand 1 (PD-L1) agents were approved for the treatment of various human malignancies. MATERIALS AND METHODS: Our study examined the expression of PD-L1 in neoplastic tissue (17 patients) and the plasma soluble (s)PD-L1 of 32 patients with ovarian carcinoma, in parallel with the levels of specific microRNAs (miRs), using immunohistochemistry, enzyme-linked immunosorbent assay (ELISA) and real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR), respectively. RESULTS: PD-L1 levels were significantly higher in the plasma of patients with ovarian cancer compared to healthy women (p=0.01). High miR200 levels were related to high sPD-L1 levels (p=0.03), whilst high miR34a levels were associated with low sPD-L1 levels (p=0.02). Immunohistochemical expression of PD-L1 by cancer cells was not related to plasma miR levels, nor to the level of sPD-L1. CONCLUSION: As well as cancer cell expression of PD-L1, a high sPD-L1 level characterizes a subset of patients with ovarian cancer. The value of this latter feature as a biomarker for the administration of anti-PD-L1/PD1 therapy needs further evaluation. Micro-RNAs, such as miR34a and miR200, may have a role in the efficacy of immunotherapy.

Autophagic flux response and glioblastoma sensitivity to radiation.

OBJECTIVE: Glioblastoma is the most common primary brain tumor in adults and one of the most lethal human tumors. It constitutes a unique non-metastasizing human tumor model with high resistance to radiotherapy and chemotherapy. The current study investigates the association between autophagic flux and glioblastoma cell resistance. METHODS: The expression kinetics of autophagy- and lysosome-related proteins following exposure of two glioblastoma cell lines (T98 and U87) to clinically relevant radiation doses was examined. Then, the response of cells resistant to radiotherapy and chemotherapy was investigated after silencing of LC3A, LC3B, and TFEB genes in vitro and in vivo. RESULTS: Following irradiation with 4 Gy, the relatively radioresistant T98 cells exhibited enhanced autophagic flux. The more radiosensitive U87 cell line suffered a blockage of autophagic flux. Silencing of LC3A, LC3B, and TFEB genes in vitro, significantly sensitized cells to radiotherapy and temozolomide (U87: P < 0.01 and < 0.05, respectively; T98: P < 0.01 and < 0.01, respectively). Silencing of the LC3A gene sensitized mouse xenografts to radiation. CONCLUSIONS: Autophagy in cancer cells may be a key factor of radio-resistance and chemo-resistance in glioblastoma cells. Blocking autophagy may improve the efficacy of radiochemotherapy for glioblastoma patients.

The Notch Pathway in Breast Cancer Progression.

OBJECTIVE: Notch signaling pathway is a vital parameter of the mammalian vascular system. In this review, the authors summarize the current knowledge about the impact of the Notch signaling pathway in breast cancer progression and the therapeutic role of Notch's inhibition. METHODS: The available literature in MEDLINE, PubMed, and Scopus, regarding the role of the Notch pathway in breast cancer progression was searched for related articles from about 1973 to 2017 including terms such as "Notch," "Breast Cancer," and "Angiogenesis." Results. Notch signaling controls the differentiation of breast epithelial cells during normal development. Studies confirm that the Notch pathway has a major participation in breast cancer progression through overexpression and/or abnormal genetic type expression of the notch receptors and ligands that determine angiogenesis. The cross-talk of Notch and estrogens, the effect of Notch in breast cancer stem cells formation, and the dependable Notch overexpression during breast tumorigenesis have been studied enough and undoubtedly linked to breast cancer development. The already applied therapeutic inhibition of Notch for breast cancer can drastically change the course of the disease. CONCLUSION: Current data prove that Notch pathway has a major participation and multiple roles during breast tumor progression. Inhibition of Notch receptors and ligands provides innovative therapeutic results and could become the therapy of choice in the next few years, even though further research is needed to reach safe conclusions.

SMER28 is a mTOR-independent small molecule enhancer of autophagy that protects mouse bone marrow and liver against radiotherapy.

Effective cytoprotectors that are selective for normal tissues could decrease radiotherapy and chemotherapy sequelae and facilitate the safe administration of higher radiation doses. This could improve the cure rates of radiotherapy for cancer patients. Autophagy is a cytoplasmic cellular process that is necessary for the clearance of damaged or aged proteins and organelles. It is a strong determinant of post-irradiation cell fate. In this study, we investigated the effect of the mTOR-independent small molecule enhancer of autophagy (SMER28) on mouse liver autophagy and post-irradiation recovery of mouse bone marrow and liver. SMER28 enhanced the autophagy flux and improved the survival of normal hepatocytes. This effect was specific for normal cells because SMER28 had no protective effect on hepatoma or other cancer cell line survival in vitro. In vivo subcutaneous administration of SMER28 protected mouse liver and bone marrow against radiation damage and facilitated survival of mice after lethal whole body or abdominal irradiation. These findings open a new field of research on autophagy-targeting radioprotectors with clinical applications in oncology, occupational, and space medicine.

Comparison of the effect of the antiandrogen apalutamide (ARN-509) versus bicalutamide on the androgen receptor pathway in prostate cancer cell lines.

Apalutamide (ARN-509) is an antiandrogen that binds selectively to androgen receptors (AR) and does not show antagonist-to-agonist switch like bicalutamide. We compared the activity of ARN versus bicalutamide on prostate cancer cell lines. The 22Rv1, PC3, and DU145 cell lines were used to study the effect of ARN and bicalutamide on the expression cytoplasmic/nuclear kinetics of AR, AR-V7 variant, phosphorylated AR, as well as the levels of the AR downstream proteins prostate-specific antigen and TMPRSS2, under exposure to testosterone and/or hypoxia. The effects on autophagic flux (LC3A, p62, TFEB, LAMP2a, cathepsin D) and cell metabolism-related enzymes (hypoxia-inducible factor 1α/2α, BNIP3, carbonic anhydrase 9, LDHA, PDH, PDH-kinase) were also studied. The 22Rv1 cell line responded to testosterone by increasing the nuclear entry of AR, AR-V7, and phosphorylated AR and by increasing the levels of prostate-specific antigen and TMPRSS2. This effect was strongly abrogated by ARN and to a clearly lower extent by bicalutamide at 10 µmol/l, both in normoxia and in hypoxia. ARN had a stronger antiproliferative effect than bicalutamide, which was prominent in the 22Rv1 hormone-responsive cell line, and completely repressed cell proliferation at a concentration of 100 µmol/l. No effect of testosterone or of antiandrogens on autophagy flux, hypoxia-related proteins, or metabolism enzyme levels was noted. The PC3 and DU145 cell lines showed poor expression of the proteins and were not responsive to testosterone. On the basis of in-vitro studies, evidence has been reported that ARN is more potent than bicalutamide in blocking the AR pathway in normoxia and in hypoxia. This reflects a more robust, dose-dependent, repressive effect on cell proliferation.

Amifostine Protects Mouse Liver Against Radiation-induced Autophagy Blockage.

BACKGROUND/AIM: Amifostine is the only selective normal tissue cytoprotector, approved for the protection against platinum toxicities and radiotherapy-induced xerostomia. Free radical scavenger and DNA repair activities have been attributed to the drug. MATERIALS AND METHODS: We investigated the effect of amifostine on autophagy, lysosomal biogenesis and lipophagy of normal mouse liver exposed to clinically relevant doses of radiation. RESULTS: The study provides evidence that ionizing radiation blocks autophagy activity and lysosomal biogenesis in normal mouse liver. Amifostine, protects the liver autophagic machinery and induces lysosomal biogenesis. By suppressing autophagy, ionizing radiation induces lipid droplet accumulation, while pre-treatment with amifostine protects lipophagy and up-regulates the TIP47 protein and mRNA levels, showing a maintenance of lipid metabolism in the liver cells. CONCLUSION: It is concluded that amifostine, aside to DNA protection activity, exerts its cytoprotective function by preventing radiation-induced blockage of autophagy, lysosomal biogenesis and lipophagy.

Inhibition of IKK-NFκB pathway sensitizes lung cancer cell lines to radiation.

OBJECTIVE: : Cancer cell radioresistance is a stumbling block in radiation therapy. The activity in the nuclear factor kappa B (NFκB) pathway correlates with anti-apoptotic mechanisms and increased radioresistance. The IKK complex plays a major role in NFκB activation upon numerous signals. In this study, we examined the interaction between ionizing radiation (IR) and different members of the IKK-NFκB pathway, as well as upstream activators, RAF1, ERK, and AKT1. METHODS: : The effect of 4 Gy of IR on the expression of the RAF1-ERK-IKK-NFκB pathway was examined in A549 and H1299 lung cancer cell lines using Western blot analysis and confocal microscopy. We examined changes in radiation sensitivity using gene silencing or pharmacological inhibitors of ERK and IKKß. RESULTS: : IKKα, IKKγ, and IκBα increased upon exposure to IR, thereby affecting nuclear levels of NFκB (phospho-p65). ERK inhibition or siRNA-mediated down-regulation of RAF1 suppressed the post-irradiation survival of the examined lung cancer cell lines. A similar effect was detected on survival upon silencing IKKα/IKKγ or inhibiting IKKß. CONCLUSIONS: : Exposure of lung cancer cells to IR results in NFκB activation via IKK. The genetic or pharmacological blockage of the RAF1-ERK-IKK-NFκB pathway sensitizes cells to therapeutic doses of radiation. Therefore, the IKK pathway is a promising target for therapeutic intervention in combination with radiotherapy.

Metabolic cooperation between co-cultured lung cancer cells and lung fibroblasts.

Cooperation of cancer cells with stromal cells, such as cancer-associated fibroblasts (CAFs), has been revealed as a mechanism sustaining cancer cell survival and growth. In the current study, we focus on the metabolic interactions of MRC5 lung fibroblasts with lung cancer cells (A549 and H1299) using co-culture experiments and studying changes of the metabolic protein expression profile and of their growth and migration abilities. Using western blotting, confocal microscopy and RT-PCR, we observed that in co-cultures MRC5 respond by upregulating pyruvate dehydrogenase (PDH) and the monocarboxylate transporter MCT1. In contrast, cancer cells increase the expression of glucose transporters (GLUT1), LDH5, PDH kinase and the levels of phosphorylated/inactivated pPDH. H1299 cells growing in the same culture medium with fibroblasts exhibit a 'metastasis-like' phenomenon by forming nests within the fibroblast area. LDH5 and pPDH were drastically upregulated in these nests. The growth rate of both MRC5 and cancer cells increased in co-cultures. Suppression of LDHA or PDK1 in cancer cells abrogates the stimulatory signal from cancer cells to fibroblasts. Incubation of MRC5 fibroblasts with lactate resulted in an increase of LDHB and of PDH expression. Silencing of PDH gene in fibroblasts, or silencing of PDK1 or LDHA gene in tumor cells, impedes cancer cell's migration ability. Overall, a metabolic cooperation between lung cancer cells and fibroblasts has been confirmed in the context of direct Warburg effect, thus the fibroblasts reinforce aerobic metabolism to support the intensified anaerobic glycolytic pathways exploited by cancer cells.

Blocking LDHA glycolytic pathway sensitizes glioblastoma cells to radiation and temozolomide.

PURPOSE: Up-regulation of lactate dehydrogenase LDHA, is a frequent event in human malignancies and relate to poor postoperative outcome. In the current study we examined the hypothesis that LDHA and anaerobic glycolysis, may contribute to the resistance of glioblastoma to radiotherapy and to temozolomide. METHODS AND MATERIALS: The expression of LDH5 isoenzyme (fully encoded by the LDHA gene) was assessed in human glioblastoma tissues. Experimental in vitro studies involved the T98 and U87 glioblastoma cell lines. Their sensitivity to radiotherapy and to temozolomide, following silencing of LDHA gene or following exposure to the LDHA chemical inhibitor 'oxamate' and to the glycolysis inhibitor '2-deoxy-d-glucose' (2DG), was studied. RESULTS: Glioblastoma tissues showed strong cytoplasmic and nuclear LDH5 expression in 0-90% (median 20%) of the neoplastic cells. T98 and U87 cell lines showed that blocking glycolysis, either with LDHA gene silencing or exposure to oxamate (30 mM) and blockage of glycolysis with 2DG (500 µM), results in enhanced radiation sensitivity, an effect that was more robust in the T98 radioresistant cell line. Furthermore, all three glycolysis targeting methods, significantly sensitized both cell lines to Temozolomide. CONCLUSIONS: The current study provides evidence that a large subgroup of human glioblastomas are highly glycolytic, and that inhibitors of glycolysis, like LDHA targeting agents, may prove of therapeutic importance by enhancing the efficacy of radiotherapy and temozolomide against this lethal disease.

Differential effect of hypoxia and acidity on lung cancer cell and fibroblast metabolism.

This study examined the metabolic response of lung cancer cells and normal lung fibroblasts to hypoxia and acidity. GLUT1 and HXKII mRNA/protein expression was up-regulated under hypoxia in the MRC5 fibroblasts and in the A549 and H1299 lung cancer cell lines, indicating intensified glucose absorption and glycolysis. Under hypoxia, the LDHA mRNA and LDH5 protein levels increased in the cancer cells but not in the fibroblasts. Acidity suppressed the above-mentioned hypoxia effect. PDH-kinase-1 (PDK1 mRNA and protein) and inactive phosphorylated-PDH protein levels were induced under hypoxia in the cancer cells, whereas these were reduced in the MRC5 lung fibroblasts. In human tissue sections, the prevalent expression patterns supported the contrasting metabolic behavior of cancer cells vs. tumor fibroblasts. The monocarboxylate/lactate transporter 1 (MCT1) was up-regulated in all the cell lines under hypoxic conditions, but it was suppressed under acidic conditions. The mitochondrial DNA (mtDNA) content per cell decreased significantly in the A549 cancer cell line under hypoxia, but it increased in the MRC5 fibroblasts. Taking into account these findings, we suggest that, under hypoxia, cancer cells intensify the anaerobic direction in glycolysis, while normal fibroblasts prefer to seek energy by intensifying the aerobic use of the available oxygen.

A pilot study on plasma levels of micro-RNAs involved in angiogenesis and vascular maturation in patients with breast cancer.

Micro-RNAs (miRNAs) have a complex role in carcinogenesis and tumour progression. Several miRNAs, such as miR-221, miR-27b and miR-132, have been implicated in the regulation of VEGF tumour angiogenic activity. In this pilot study, we assessed angiogenesis and DLL4+ vascular maturation index (VMI) in breast cancer tissues, in parallel with the plasma levels of the above-mentioned miRNAs. Significantly higher than control samples pre-operative levels were recorded in 10/11, 7/11 and 9/11 cases for the miR-221, miR-27b and miR-132, respectively. Seven days after surgery, a significant reduction of these miRNAs was noted in 6/11, 3/11 and 2/11 cases, respectively. High pre-operative levels of miR-27b were linked with node metastasis (p = 0.04). High pre-operative levels of miR-132 were linked with small tumours (p = 0.03) and her2 overexpression (p = 0.003). The DLL4+ VMI ranged from 26 to 69% (median 45%). Patients with poor DLL4+ VMI had significantly high pre-operative and post-operative levels of miR-221 (p = 0.01 and 0.02, respectively) and high post-operative levels of miR-132 (p = 0.02). It is concluded that angiogenesis-related miRs as detected in the plasma of patients may prove of a useful tool in the identification of patients with poor vascular maturation and high risk to develop metastasis. Whether such miRs may identify patients who would benefit from vascular normalization policies is a hypothesis that emerges from the current study.

Normal tissue radioprotection by amifostine via Warburg-type effects.

The mechanism of Amifostine (WR-2721) mediated radioprotection is poorly understood. The effects of amifostine on human basal metabolism, mouse liver metabolism and on normal and tumor hepatic cells were studied. Indirect calorimetric canopy tests showed significant reductions in oxygen consumption and of carbon dioxide emission in cancer patients receiving amifostine. Glucose levels significantly decreased and lactate levels increased in patient venous blood. Although amifostine in vitro did not inhibit the activity of the prolyl-hydroxylase PHD2, experiments with mouse liver showed that on a short timescale WR-1065 induced expression of the Hypoxia Inducible Factor HIF1α, lactate dehydrogenase LDH5, glucose transporter GLUT2, phosphorylated pyruvate dehydrogenase pPDH and PDH-kinase. This effect was confirmed on normal mouse NCTC hepatocytes, but not on hepatoma cells. A sharp reduction of acetyl-CoA and ATP levels in NCTC cells indicated reduced mitochondrial usage of pyruvate. Transient changes of mitochondrial membrane potential and reactive oxygen species ROS production were evident. Amifostine selectively protects NCTC cells against radiation, whilst HepG2 neoplastic cells are sensitized. The radiation protection was correlates with HIF levels. These findings shed new light on the mechanism of amifostine cytoprotection and encourage clinical research with this agent for the treatment of primary and metastatic liver cancer.

Repression of the autophagic response sensitises lung cancer cells to radiation and chemotherapy.

BACKGROUND: The cellular autophagic response to radiation is complex. Various cells and tissues respond differentially to radiation, depending on both the dose of exposure and the time post irradiation. In the current study, we determined the autophagosomal and lysosomal response to radiation in lung cancer cell lines by evaluating the expression of the associated proteins, as well as the effect of relevant gene silencing in radio and chemosensitisation. Furthermore, tumour sensitisation was evaluated in in vivo autophagic gene silencing model after irradiation. METHODS: A549 and H1299 cell lines were utilised as in vitro cancer models. Both cell lines were transfected with various small-interfering RNAs, silencing auto-lysosomal genes, and irradiated with 4 Gy. Cell growth response was evaluated with AlamarBlue assay. Western blot and confocal microscopy were utilised for the characterisation of the auto-lysosomal flux. Also, the H1299 cell line was stable transfected with small-hairpin RNA of the MAP1LC3A gene, and the tumour radiosensitisation in Athymic Nude-Foxn1(nu) was evaluated. RESULTS: Following exposure to 4 Gy of radiation, A549 cells exhibited a significant induction of the autophagic flux, which was not supported by transcriptional activation of auto-lysosomal genes (LC3A, LC3B, p62, TFEB and LAMP2a), resulting in aggresome accumulation. Recovery of transcriptional activity and autophagy efficacy occurred 7 days post irradiation. Alternatively, H1299 cells, a relatively radio-resistant cell line, sharply responded with an early (at 2 days) transcriptional activation of auto-lysosomal genes that sustained an effective autophagosomal flux, resulting in adequate aggresome clearance. Subsequently, we tested the silencing of four genes (LC3A, LC3B, TFEB and LAMP2a), confirming a significant radiosensitisation and chemosensitisation to various chemotherapeutic agents, including cisplatin and taxanes. In mouse xenografts, exposure to radiation significantly reduced tumour growth (P<0.001), which was exacerbated among shLC3A-H1299 transfected tumours. CONCLUSIONS: The ability of lung cancer cells to survive after irradiation at 4 Gy depends on their ability to sustain a functional autophagic flux. Abrogation of such ability results in increased radiosensitivity and susceptibility to various chemotherapy agents. Selective inhibitors of cancer cell autophagic function may prove important for the eradication of lung cancer.

Genotoxic effect of tocolytic drug ritodrine in combination with smoking during pregnancy.

OBJECTIVE: Tocolytic drugs are used widely in order to prevent preterm birth. Ritodrine, is the only food and drug administration (FDA) approved drug for tocolytic use. We estimated the cytogenetic effect of ritodrine administered as maternal therapy, alone or in combination with smoking, in women and their neonates. METHODS: Lymphocyte and fibroblasts cultures were evaluated and three indices were analyzed; sister chromatid exchanges (SCEs), proliferation rate index (PRI) and mitotic index (MI) as well as average generation time (AGT) and population doubling time (PDT). Campothacin (CPT-11) was used as a positive control. RESULTS: Administration of ritodrine up to a month revealed significant reduction of SCEs/cell in neonates in the presence or absence of the mutagenic agent. A statistical significant increase on SCEs, for mothers and neonates, was noticed in neonate's lymphocytes when tocolytic therapy was over a month. Ritodrine revealed a cytoprotective action against smoking when the two factors were combined, but the synergistic action of ritodrine with smoking increased genotoxicity, cytostaticity and cytotoxicity of neonates after long administration (1-3 months). CONCLUSIONS: The time-depended genotoxic, cytostatic and cytotoxic action of ritodrine alone or in combination with smoking suggests that its administration should not exceed the time period of a month.

Autophagosome Proteins LC3A, LC3B and LC3C Have Distinct Subcellular Distribution Kinetics and Expression in Cancer Cell Lines.

LC3s (MAP1-LC3A, B and C) are structural proteins of autophagosomal membranes, widely used as biomarkers of autophagy. Whether these three LC3 proteins have a similar biological role in autophagy remains obscure. We examine in parallel the subcellular expression patterns of the three LC3 proteins in a panel of human cancer cell lines, as well as in normal MRC5 fibroblasts and HUVEC, using confocal microscopy and western blot analysis of cell fractions. In the cytoplasm, there was a minimal co-localization between LC3A, B and C staining, suggesting that the relevant autophagosomes are formed by only one out of the three LC3 proteins. LC3A showed a perinuclear and nuclear localization, while LC3B was equally distributed throughout the cytoplasm and localized in the nucleolar regions. LC3C was located in the cytoplasm and strongly in the nuclei (excluding nucleoli), where it extensively co-localized with the LC3A and the Beclin-1 autophagy initiating protein. Beclin 1 is known to contain a nuclear trafficking signal. Blocking nuclear export function by Leptomycin B resulted in nuclear accumulation of all LC3 and Beclin-1 proteins, while Ivermectin that blocks nuclear import showed reduction of accumulation, but not in all cell lines. Since endogenous LC3 proteins are used as major markers of autophagy in clinical studies and cell lines, it is essential to check the specificity of the antibodies used, as the kinetics of these molecules are not identical and may have distinct biological roles. The distinct subcellular expression patterns of LC3s provide a basis for further studies.

Survival Fraction at 2 Gy and γH2AX Expression Kinetics in Peripheral Blood Lymphocytes From Cancer Patients: Relationship With Acute Radiation-Induced Toxicities.

PURPOSE: Predictive assays for acute radiation toxicities would be clinically relevant in radiation oncology. We prospectively examined the predictive role of the survival fraction at 2 Gy (SF2) and of γH2AX (double-strand break [DSB] DNA marker) expression kinetics in peripheral blood mononuclear cells (PBMCs) from cancer patients before radiation therapy. METHODS AND MATERIALS: SF2 was measured with Trypan Blue assay in the PBMCs from 89 cancer patients undergoing radiation therapy at 4 hours (SF2[4h]) and 24 hours (SF2[24h]) after ex vivo irradiation. Using Western blot analysis and band densitometry, we further assessed the expression of γH2AX in PBMC DNA at 0 hours, 30 minutes, and 4 hours (33 patients) and 0 hour, 4 hours, and 24 hours (56 patients), following ex vivo irradiation with 2 Gy. Appropriate ratios were used to characterize each patient, and these were retrospectively correlated with early radiation therapy toxicity grade. RESULTS: The SF2(4h) was inversely correlated with the toxicity grade (P=.006). The γH2AX-ratio(30min) (band density of irradiated/non-irradiated cells at 30 minutes) revealed, similarly, a significant inverse association (P=.0001). The DSB DNA repair rate from 30 minutes to 4 hours, calculated as the relative RγH2AX-ratio (γH2AX-ratio(4h)/γH2AX-ratio(30min)) showed a significant direct association with high toxicity grade (P=.01). CONCLUSIONS: Our results suggest that SF2 is a significant radiation sensitivity index for patients undergoing radiation therapy. γH2AX Western blot densitometry analysis provided 2 important markers of normal tissue radiation sensitivity. Low γH2AX expression at 30 minutes was linked with high toxicity grade, suggesting that poor γH2AX repair activity within a time frame of 30 minutes after irradiation predicts for poor radiation tolerance. On the other hand, rapid γH2AX content restoration at 4 hours after irradiation, compatible with efficient DSB repair ability, predicts for increased radiation tolerance.