Safety and clinical activity of autologous RNA chimeric antigen receptor T-cell therapy in myasthenia gravis (MG-001): a prospective, multicentre, open-label, non-randomised phase 1b/2a study.

BACKGROUND: Chimeric antigen receptor (CAR) T cells are highly effective in treating haematological malignancies, but associated toxicities and the need for lymphodepletion limit their use in people with autoimmune disease. To explore the use of CAR T cells for the treatment of people with autoimmune disease, and to improve their safety, we engineered them with RNA (rCAR-T)-rather than the conventional DNA approach-to target B-cell maturation antigen (BCMA) expressed on plasma cells. To test the suitability of our approach, we used rCAR-T to treat individuals with myasthenia gravis, a prototypical autoantibody disease mediated partly by pathogenic plasma cells. METHODS: MG-001 was a prospective, multicentre, open-label, phase 1b/2a study of Descartes-08, an autologous anti-BCMA rCAR-T therapy, in adults (ie, aged ≥18 years) with generalised myasthenia gravis and a Myasthenia Gravis Activities of Daily Living (MG-ADL) score of 6 or higher. The study was done at eight sites (ie, academic medical centres or community neurology clinics) in the USA. Lymphodepletion chemotherapy was not used. In part 1 (phase 1b), participants with Myasthenia Gravis Foundation of America (MGFA) disease class III-IV generalised myasthenia gravis received three ascending doses of Descartes-08 to determine a maximum tolerated dose. In part 2 (phase 2a), participants with generalised myasthenia gravis with MGFA disease class II-IV received six doses at the maximum tolerated dose in an outpatient setting. The primary objective was to establish safety and tolerability of Descartes-08; secondary objectives were to assess myasthenia gravis disease severity and biomarkers in participants who received Descartes-08. This trial is registered with clinicaltrials.gov, NCT04146051. FINDINGS: We recruited 16 individuals for screening between Jan 7, 2020 and Aug 3, 2022. 14 participants were enrolled (n=3 in part 1, n=11 in part 2). Ten participants were women and four were men. Two individuals did not qualify due to low baseline MG-ADL score (n=1) or lack of generalised disease (n=1). Median follow-up in part 2 was 5 months (range 3-9 months). There was no dose-limiting toxicity, cytokine release syndrome, or neurotoxicity. Common adverse events were headache (six of 14 participants), nausea (five of 14), vomiting (three of 14), and fever (four of 14), which resolved within 24 h of infusion. Fevers were not associated with increased markers of cytokine release syndrome (IL-6, IL-2, and TNF). Mean improvements from baseline to week 12 were -6 (95% CI -9 to -3) for MG-ADL score, -7 (-11 to -3) for Quantitative Myasthenia Gravis score, -14 (-19 to -9) for Myasthenia Gravis Composite score, and -9 (-15 to -3) for Myasthenia Gravis Quality of Life 15-revised score. INTERPRETATION: In this first study of an rCAR-T therapy in individuals with an autoimmune disease, Descartes-08 appeared to be safe and was well tolerated. Descartes-08 infusions were followed by clinically meaningful decreases on myasthenia gravis severity scales at up to 9 months of follow-up. rCAR-T therapy warrants further investigation as a potential new treatment approach for individuals with myasthenia gravis and other autoimmune diseases. FUNDING: Cartesian Therapeutics and National Institute of Neurological Disorders and Stroke of the National Institutes of Health.

Preclinical evaluation of CD8+ anti-BCMA mRNA CAR T cells for treatment of multiple myeloma.

Chimeric antigen receptor (CAR) T-cell therapy remains limited to select centers that can carefully monitor adverse events. To broaden use of CAR T cells in community clinics and in a frontline setting, we developed a novel CD8+ CAR T-cell product, Descartes-08, with predictable pharmacokinetics for treatment of multiple myeloma. Descartes-08 is engineered by mRNA transfection to express anti-BCMA CAR for a defined length of time. Descartes-08 expresses anti-BCMA CAR for 1 week, limiting risk of uncontrolled proliferation; produce inflammatory cytokines in response to myeloma target cells; and are highly cytolytic against myeloma cells regardless of the presence of myeloma-protecting bone marrow stromal cells, exogenous a proliferation-inducing ligand, or drug resistance including IMiDs. The magnitude of cytolysis correlates with anti-BCMA CAR expression duration, indicating a temporal limit in activity. In the mouse model of aggressive disseminated human myeloma, Descartes-08 induces BCMA CAR-specific myeloma growth inhibition and significantly prolongs host survival (p < 0.0001). These preclinical data, coupled with an ongoing clinical trial of Descartes-08 in relapsed/refractory myeloma (NCT03448978) showing preliminary durable responses and a favorable therapeutic index, have provided the framework for a recently initiated trial of an optimized/humanized version of Descartes-08 (i.e., Descartes-11) in newly diagnosed myeloma patients with residual disease after induction therapy.

Global variability of the human IgG glycome.

Immunoglobulin G (IgG) is the most abundant serum antibody which structural characteristics and effector functions are modulated through the attachment of various sugar moieties called glycans. Composition of the IgG N-glycome changes with age of an individual and in different diseases. Variability of IgG glycosylation within a population is well studied and is known to be affected by both genetic and environmental factors. However, global inter-population differences in IgG glycosylation have never been properly addressed. Here we present population-specific N-glycosylation patterns of IgG, analyzed in 5 different populations totaling 10,482 IgG glycomes, and of IgG's fragment crystallizable region (Fc), analyzed in 2,579 samples from 27 populations sampled across the world. Country of residence associated with many N-glycan features and the strongest association was with monogalactosylation where it explained 38% of variability. IgG monogalactosylation strongly correlated with the development level of a country, defined by United Nations health and socioeconomic development indicators, and with the expected lifespan. Subjects from developing countries had low levels of IgG galactosylation, characteristic for inflammation and ageing. Our results suggest that citizens of developing countries may be exposed to environmental factors that can cause low-grade chronic inflammation and the apparent increase in biological age.

Combining 2-deoxy-D-glucose with fenofibrate leads to tumor cell death mediated by simultaneous induction of energy and ER stress.

Unregulated growth and replication as well as an abnormal microenvironment, leads to elevated levels of stress which is a common trait of cancer. By inducing both energy and endoplasmic reticulum (ER) stress, 2-Deoxy-glucose (2-DG) is particularly well-suited to take advantage of the therapeutic window that heightened stress in tumors provides. Under hypoxia, blocking glycolysis with 2-DG leads to significant lowering of ATP resulting in energy stress and cell death in numerous carcinoma cell types. In contrast, under normoxia, 2-DG at a low-concentration is not toxic in most carcinomas tested, but induces growth inhibition, which is primarily due to ER stress. Here we find a synergistic toxic effect in several tumor cell lines in vitro combining 2-DG with fenofibrate (FF), a drug that has been safely used for over 40 years to lower cholesterol in patients. This combination induces much greater energy stress than either agent alone, as measured by ATP reduction, increased p-AMPK and downregulation of mTOR. Inhibition of mTOR results in blockage of GRP78 a critical component of the unfolded protein response which we speculate leads to greater ER stress as observed by increased p-eIF2α. Moreover, to avoid an insulin response and adsorption by the liver, 2-DG is delivered by slow-release pump yielding significant anti-tumor control when combined with FF. Our results provide promise for developing this combination clinically and others that combine 2-DG with agents that act synergistically to selectively increase energy and ER stress to a level that is toxic to numerous tumor cell types.

The role of hypoxia in pancreatic cancer: a potential therapeutic target?

One of the key factors that correlates with poor survival of patients with pancreatic cancer is the extent of hypoxic areas within the tumor tissue. The adaptation of pancreatic cancer cells to limited oxygen delivery promotes the induction of an invasive and treatment-resistant phenotype, triggering metastases at an early stage of tumor development, which resist in most cases adjuvant therapies following tumor resection. In this article, the authors summarize the evidence demonstrating the significance of hypoxia in pancreatic cancer pathogenesis and discuss the possible hypoxia-induced mechanisms underlying its aggressive nature. We then conclude with promising strategies that target hypoxia-adapted pancreatic cancer cells.

Elevating the Horizon: Emerging Molecular and Genomic Targets in the Treatment of Advanced Urothelial Carcinoma.

Despite recent advances in the identification of genomic alterations that lead to urothelial oncogenesis in vitro, patients with advanced urothelial carcinomas continue to have poor clinical outcomes. In the present review, we focus on targeted therapies that have yielded the most promising results alone or combined with traditional chemotherapy, including the antiangiogenesis agent bevacizumab, the human epidermal growth factor receptor 2 antibody trastuzumab, and the tyrosine kinase inhibitor cabozantinib. We also describe ongoing and developing clinical trials that use innovative approaches, including dose-dense scheduling of singular chemotherapy combinations, prospective screening of tumor tissues for mutational targets and biomarkers to predict chemosensitivity before the determination of the therapeutic regimen, and novel agents that target proteins in the immune checkpoint regulation pathway (programmed cell death protein 1 [PD-1] and anti-PD-ligand 1) that have shown significant potential in preclinical models and early clinical trials. New agents and targeted therapies, alone or combined with traditional chemotherapy, will only be validated through accrual to developing clinical trials that aim to translate these therapies into individualized treatments and improved survival rates in urothelial carcinoma.

Identification of active chemotherapy regimens in advanced biliary tract carcinoma: a review of chemotherapy trials in the past two decades.

Biliary tract carcinoma is a rare malignancy. We performed a comprehensive analysis of published prospective clinical trials in advanced biliary tract carcinoma in an attempt to identify active regimens in this setting. We searched PubMed and abstracts presented at the American Society of Clinical Oncology, Gastrointestinal Cancer Symposium, European Society of Medical Oncology and European Cancer Organization conferences for clinical trials in this disease. We found 83 trials. The effect of gemcitabine on overall survival benefit showed a strong trend (p = 0.014) and an improvement in progression-free survival (p = 0.003). Gemcitabine-based regimens containing 5-fluorouracil showed a trend toward an improved overall survival (p = 0.047) relative to platinum agents. Our findings support gemcitabine as the chemotherapy backbone for the treatment of patients with cholangiocarcinoma. Gemcitabine plus 5-fluorouracil combinations warrant further investigations.

The wonders of 2-deoxy-D-glucose.

Through the eons of time, out of all possible configurations, nature has selected glucose not only as a vital source of energy to sustain life but also as the molecule who's structure supplies the appropriate elements required for a cell to grow and multiply. This understanding, at least in part, explains the profound effects that the analog of glucose, 2-deoxy-d-glucose, has been shown to have on as common and widespread diseases as cancer, viral infection, aging-related morbidity, epilepsy, and others. This review is confined to summarizing some of the salient findings of this remarkable compound as they relate mainly to cancer.

Targeting cisplatin-resistant human tumor cells with metabolic inhibitors.

PURPOSE: Although cisplatin is the drug of choice in treating lung cancer patients, relapse and resistance is a common drawback to its clinical effectiveness. Based on cisplatin's reported ability to interfere with numerous cellular components, including mitochondria, we probed alterations in metabolism in cisplatin-resistant tumor cell lines to reveal targets for overcoming this important form of resistance. METHODS: Cisplatin-resistant lung and ovarian cancer cell lines were used to evaluate the efficacy of metabolic inhibitors for selectively targeting cisplatin-resistant cells under varying oxygen conditions. RESULTS: Three cisplatin-resistant cancer cell lines expressed lower HKII protein when compared to the respective cisplatin-sensitive cancer cell lines from which they were derived. Under anaerobic and hypoxic conditions, treatment with the glycolytic inhibitors 2-deoxyglucose (2-DG) and 2-fluorodeoxyglucose (2-FDG) correlated with increased cytotoxicity and more pronounced decreases in lactate production in cisplatin-resistant cells, indicating a greater blockage of glycolysis. Knockdown of HKI or HKII with siRNA in the parental lung cancer cell lines led to increased 2-FDG-induced cell death under anaerobic conditions. Under normal oxygen conditions, blockage of either fatty acid oxidation or deprivation of glutamine resulted in cell death in cisplatin-resistant lung cancer cell lines. CONCLUSIONS: Altered hexokinase levels in cisplatin-resistant cancer cell lines leads to increased sensitivity to glycolytic inhibition under anaerobic conditions, whereas under normoxic conditions, blockage of either fatty acid oxidation or deprivation of glutamine leads to cell death. These findings may be clinically applicable when considering cisplatin resistance.

Increased sensitivity to glucose starvation correlates with downregulation of glycogen phosphorylase isoform PYGB in tumor cell lines resistant to 2-deoxy-D-glucose.

BACKGROUND: As tumors evolve, they upregulate glucose metabolism while also encountering intermittent periods of glucose deprivation. Here, we investigate mechanisms by which pancreatic cancer cells respond to therapeutic (2-deoxy-D-glucose, 2-DG) and physiologic (glucose starvation, GS) forms of glucose restriction. METHODS: From a tumor cell line (1420) that is unusually sensitive to 2-DG under normoxia, low (14DG2)- and high (14DG5)-dose resistant cell lines were selected and used to probe the metabolic pathways involved with their response to different forms of glucose deprivation. RESULTS: Muted induction of the unfolded protein response was found to correlate with resistance to 2-DG. Additionally, 14DG2 displayed reduced 2-DG uptake, while 14DG5 was cross-resistant to tunicamycin, suggesting it has enhanced ability to manage glycosylation defects. Conversely, 2-DG-resistant cell lines were more sensitive than their parental cell line to GS, which coincided with lowered levels of glycogen phosphorylase (PYGB) and reduced breakdown of glycogen to glucose in the 2-DG-resistant cell lines. Moreover, by inhibiting PYGB in the parental cell line, sensitivity to GS was increased. CONCLUSIONS: Overall, the data demonstrate that the manner in which glucose is restricted in tumor cells, i.e., therapeutic or physiologic, leads to differential biological responses involving distinct glucose metabolic pathways. Moreover, in evolving tumors where glucose restriction occurs, the identification of PYGB as a metabolic target may have clinical application.

Conversion of 2-deoxyglucose-induced growth inhibition to cell death in normoxic tumor cells.

BACKGROUND: Inhibition of glucose metabolism has recently become an attractive target for cancer treatment. Accordingly, since 2-deoxyglucose (2-DG) competes effectively with glucose, it has come under increasing scrutiny as a therapeutic agent. The initial response of tumor cells to 2-DG is growth inhibition, which is thought to conserve energy and consequently protect cells from its ATP-lowering effects as a glycolytic inhibitor. However, since 2-DG also mimics mannose and thereby interferes with N-linked glycosylation, the question is raised of how this sugar analog inhibits tumor cell growth and whether the mechanism by which it protects cells can be manipulated to convert 2-DG-induced growth inhibition to cell death. METHODS: Cell growth and death were measured via counting viable and dead cells based on trypan blue exclusion. Markers of ATP reduction and the unfolded protein response (UPR) were detected by Western blot. Protein functions were manipulated through chemical compounds, siRNA and the use of gene-specific wild-type and knock-out mouse embryonic fibroblasts (MEFs). RESULTS: At 2-DG concentrations that can be achieved in human plasma without causing significant side effects, we find (a) It induces growth inhibition predominantly by interference with glycosylation, which leads to accumulation of unfolded proteins in the endoplasmic reticulum activating the UPR; (b) Inhibition of PERK (but not ATF6 or IRE1), a major component of the UPR, leads to conversion of 2-DG-induced growth inhibition to cell death and (c) secondarily to PERK, inhibition of GCN2, a kinase that is activated in response to low intracellular glutamine, increases 2-DG's cytotoxic effects in PERK -/- MEFs. CONCLUSIONS: Overall, these findings present a novel anticancer strategy that can be translated into therapeutic gain as they uncover the metabolic target PERK, and to a lesser degree GCN2, that when inhibited convert 2-DG's static effect to a toxic one in tumor cells growing under normoxia.

A phase I dose-escalation trial of 2-deoxy-D-glucose alone or combined with docetaxel in patients with advanced solid tumors.

PURPOSE: This phase I trial was initiated to evaluate the safety, pharmacokinetics (PK) and maximum tolerated dose (MTD) of the glycolytic inhibitor, 2-deoxy-D-glucose (2DG) in combination with docetaxel, in patients with advanced solid tumors. METHODS: A modified accelerated titration design was used. 2DG was administered orally once daily for 7 days every other week starting at a dose of 2 mg/kg and docetaxel was administered intravenously at 30 mg/m(2) for 3 of every 4 weeks beginning on day 1 of week 2. Following the completion of dose escalation, cohorts of patients were then treated with 2DG for 21 days or every day of each 4-week cycle for up to 12 cycles. RESULTS: Thirty-four patients were enrolled: 21 on every other week, 6 on a 21 of 28-day cycle and 7 on the continuous 2DG dosing schedule. There were no dose-limiting toxicities which met the MTD criteria. The most common adverse events were fatigue, sweating, dizziness and nausea mimicking the hypoglycemic symptoms expected from 2DG administration. Therefore, 63 mg/kg was selected as the clinically tolerable dose. The most significant adverse effects noted at 63-88 mg/kg doses were reversible hyperglycemia (100 %), gastrointestinal bleeding (6 %) and reversible grade 3 QTc prolongation (22 %). Eleven patients (32 %) had stable disease, 1 patient (3 %) partial response and 22 patients (66 %) progressive disease as their best response. There was no PK interaction between 2DG and docetaxel. CONCLUSION: The recommended dose of 2DG in combination with weekly docetaxel is 63 mg/kg/day with tolerable adverse effects.

Activation of the unfolded protein response by 2-deoxy-D-glucose inhibits Kaposi's sarcoma-associated herpesvirus replication and gene expression.

Lytic replication of the Kaposi's sarcoma-associated herpesvirus (KSHV) is essential for the maintenance of both the infected state and characteristic angiogenic phenotype of Kaposi's sarcoma and thus represents a desirable therapeutic target. During the peak of herpesvirus lytic replication, viral glycoproteins are mass produced in the endoplasmic reticulum (ER). Normally, this leads to ER stress which, through an unfolded protein response (UPR), triggers phosphorylation of the α subunit of eukaryotic initiation factor 2 (eIF2α), resulting in inhibition of protein synthesis to maintain ER and cellular homeostasis. However, in order to replicate, herpesviruses have acquired the ability to prevent eIF2α phosphorylation. Here we show that clinically achievable nontoxic doses of the glucose analog 2-deoxy-d-glucose (2-DG) stimulate ER stress, thereby shutting down eIF2α and inhibiting KSHV and murine herpesvirus 68 replication and KSHV reactivation from latency. Viral cascade genes that are involved in reactivation, including the master transactivator (RTA) gene, glycoprotein B, K8.1, and angiogenesis-regulating genes are markedly decreased with 2-DG treatment. Overall, our data suggest that activation of UPR by 2-DG elicits an early antiviral response via eIF2α inactivation, which impairs protein synthesis required to drive viral replication and oncogenesis. Thus, induction of ER stress by 2-DG provides a new antiherpesviral strategy that may be applicable to other viruses.

Distribution of Bim determines Mcl-1 dependence or codependence with Bcl-xL/Bcl-2 in Mcl-1-expressing myeloma cells.

Dependence on Bcl-2 proteins is a common feature of cancer cells and provides a therapeutic opportunity. ABT-737 is an antagonist of antiapoptotic Bcl-2 proteins and therefore is a good predictor of Bcl-x(L)/Bcl-2 dependence. Surprisingly, analysis of Mcl-1-dependent multiple myeloma cell lines revealed codependence on Bcl-2/Bcl-x(L) in half the cells tested. Codependence is not predicted by the expression level of antiapoptotic proteins, rather through interactions with Bim. Consistent with these findings, acquired resistance to ABT-737 results in loss of codependence through redistribution of Bim to Mcl-1. Overall, these results suggest that complex interactions, and not simply expression patterns of Bcl-2 proteins, need to be investigated to understand Bcl-2 dependence and how to better use agents, such as ABT-737.

2-Deoxy-D-glucose activates autophagy via endoplasmic reticulum stress rather than ATP depletion.

PURPOSE: The glucose analog and glycolytic inhibitor 2-deoxy-D-glucose (2-DG), which is currently under clinical evaluation for targeting cancer cells, not only blocks glycolysis thereby reducing cellular ATP, but also interferes with N-linked glycosylation, which leads to endoplasmic reticulum (ER) stress and an unfolded protein response (UPR). Both bioenergetic challenge and ER stress have been shown to activate autophagy, a bulk cellular degradation process that plays either a pro- or anti-death role. Here, we investigate which pathway 2-DG interferes with that activates autophagy and the role of this process in modulating 2-DG-induced toxicity. METHODS: Pancreatic cancer cell line 1420, melanoma cell line MDA-MB-435 and breast cancer cell line SKBR3 were used to investigate the relationship between induction by 2-DG treatment of ER stress/UPR, ATP reduction and activation of autophagy. ER stress/UPR (Grp78 and CHOP) and autophagy (LC3B II) markers were assayed by immunoblotting, while ATP levels were measured using the CellTiter-Glo Luminescent Cell Viability Assay. Autophagy was also measured by immunofluorescence utilizing LC3B antibody. Cell death was detected with a Vi-Cell cell viability analyzer using trypan blue exclusion. RESULTS: In the three different cancer cell lines described earlier, we find that 2-DG upregulates autophagy, increases ER stress and lowers ATP levels. Addition of exogenous mannose reverses 2-DG-induced autophagy and ER stress but does not recover the lowered levels of ATP. Moreover, under anaerobic conditions where 2-DG severely depletes ATP, autophagy is diminished rather than activated, which correlates with lowered levels of the ER stress marker Grp78. Additionally, when autophagy is blocked by siRNA, cell sensitivity to 2-DG is increased corresponding with upregulation of ER stress-mediated apoptosis. Similar increased toxicity is observed with 3-methyladenine, a known autophagy inhibitor. In contrast, rapamycin which enhances autophagy reduces 2-DG-induced toxicity. CONCLUSIONS: Overall, these results indicate that the major mechanism by which 2-DG stimulates autophagy is through ER stress/UPR and not by lowering ATP levels. Furthermore, autophagy plays a protective role against 2-DG-elicited cell death apparently by relieving ER stress. These data suggest that combining autophagy inhibitors with 2-DG may be useful clinically.

Antiangiogenic activity of 2-deoxy-D-glucose.

BACKGROUND: During tumor angiogenesis, endothelial cells (ECs) are engaged in a number of energy consuming biological processes, such as proliferation, migration, and capillary formation. Since glucose uptake and metabolism are increased to meet this energy need, the effects of the glycolytic inhibitor 2-deoxy-D-glucose (2-DG) on in vitro and in vivo angiogenesis were investigated. METHODOLOGY/PRINCIPAL FINDINGS: In cell culture, 2-DG inhibited EC growth, induced cytotoxicity, blocked migration, and inhibited actively forming but not established endothelial capillaries. Surprisingly, 2-DG was a better inhibitor of these EC properties than two more efficacious glycolytic inhibitors, 2-fluorodeoxy-D-glucose and oxamate. As an alternative to a glycolytic inhibitory mechanism, we considered 2-DG's ability to interfere with endothelial N-linked glycosylation. 2-DG's effects were reversed by mannose, an N-linked glycosylation precursor, and at relevant concentrations 2-DG also inhibited synthesis of the lipid linked oligosaccharide (LLO) N-glycosylation donor in a mannose-reversible manner. Inhibition of LLO synthesis activated the unfolded protein response (UPR), which resulted in induction of GADD153/CHOP and EC apoptosis (TUNEL assay). Thus, 2-DG's effects on ECs appeared primarily due to inhibition of LLOs synthesis, not glycolysis. 2-DG was then evaluated in two mouse models, inhibiting angiogenesis in both the matrigel plug assay and the LH(BETA)T(AG) transgenic retinoblastoma model. CONCLUSIONS/SIGNIFICANCE: In conclusion, 2-DG inhibits endothelial cell angiogenesis in vitro and in vivo, at concentrations below those affecting tumor cells directly, most likely by interfering with N-linked glycosylation rather than glycolysis. Our data underscore the importance of glucose metabolism on neovascularization, and demonstrate a novel approach for anti-angiogenic strategies.

A novel functional CT contrast agent for molecular imaging of cancer.

The purpose of this study was to investigate the feasibility of using a 2-deoxy-d-glucose (2-DG) labeled gold nanoparticle (AuNP-2-DG) as a functionally targeted computed tomography (CT) contrast agent to obtain high-resolution metabolic and anatomic information of tumor in a single CT scan. Gold nanoparticles (AuNPs) were fabricated and were conjugated with 1-DG or 2-DG. 1-DG provides an excellent comparison since it is known to interfere with the ability of the glucose transporter to recognize the sugar moiety. The human alveolar epithelial cancer cell line, A-549, was chosen for the in vitro cellular uptake assay. Three groups of cell samples were incubated with the 1-DG or 2-DG labeled AuNP and the unlabeled AuNP. Following the incubation, the cells were washed with sterile phosphate buffered saline to remove the excess AuNPs and spun using a centrifuge. The cell pellets were imaged using a microCT scanner immediately after the centrifugation. Internalization of AuNP-2-DG is verified using transmission electron microscopy imaging. Significant contrast enhancement in the cell samples incubated with the AuNP-2-DG with respect to the cell samples incubated with the unlabeled AuNP and the AuNP-1-DG was observed in multiple CT slices. Results from our in vitro experiments suggest that the AuNP-2-DG may be used as a functional CT contrast agent to provide high-resolution metabolic and anatomic information in a single CT scan. These results justify further in vitro and in vivo experiments to study the feasibility of using the AuNP-2-DG as a functional CT contrast agent in radiation therapy settings.

AuNP-DG: deoxyglucose-labeled gold nanoparticles as X-ray computed tomography contrast agents for cancer imaging.

PURPOSE: To study the feasibility of using 2-deoxy-D-glucose (2-DG)-labeled gold nanoparticle (AuNP-DG) as a computed tomography (CT) contrast agent with tumor targeting capability through in vitro experiments. PROCEDURES: Gold nanoparticles (AuNP) were fabricated and were conjugated with 2-deoxy-D-glucose. The human alveolar epithelial cancer cell line, A-549, was chosen for the in vitro cellular uptake assay. Two groups of cell samples were incubated with the AuNP-DG and the unlabeled AuNP, respectively. Following the incubation, the cells were washed with sterile PBS to remove the excess gold nanoparticles and spun to cell pellets using a centrifuge. The cell pellets were imaged using a microCT scanner immediately after the centrifugation. The reconstructed CT images were analyzed using a commercial software package. RESULTS: Significant contrast enhancement in the cell samples incubated with the AuNP-DG with respect to the cell samples incubated with the unlabeled AuNP was observed in multiple CT slices. CONCLUSIONS: Results from this study demonstrate enhanced uptake of 2-DG-labeled gold nanoparticle by cancer cells in vitro and warrant further experiments to study the exact molecular mechanism by which the AuNP-DG is internalized and retained in the tumor cells.

High endoplasmic reticulum activity renders multiple myeloma cells hypersensitive to mitochondrial inhibitors.

Multiple myeloma (MM) cells continuously secrete large amounts of immunoglobulins that are folded in the endoplasmic reticulum (ER) whose function depend on the Ca(2+) concentration inside its lumen. Recently, it was shown that the ER membrane leaks Ca(2+) that is captured and delivered back by mitochondria in order to prevent its loss. Thus, we hypothesized that the highly active and abundant ER in MM cells results in greater Ca(2+)-regulation by mitochondria which would render them sensitive to mitochondrial inhibitors. Here, we indeed find that Ca(2+) leak is greater in 3 MM, when compared to 2 B-cell leukemia cell lines. Moreover, this greater leak in MM cells is associated with hypersensitivity to various mitochondrial inhibitors, including CCCP. Consistent with our hypothesis, CCCP is more potent in inducing the unfolded protein response marker, CHOP/GADD153 in MM versus B-cell leukemia lines. Additionally, MM cells are found to be significantly more sensitive to clinically used fenofibrate and troglitazone, both of which were recently shown to have inhibitory effects on mitochondrial function. Overall, our results demonstrate that the unusually high ER activity in MM cells may be exploited for therapeutic benefit through the use of mitochondrial inhibitors including troglitazone and fenofibrate.

GHRH antagonist causes DNA damage leading to p21 mediated cell cycle arrest and apoptosis in human colon cancer cells.

We investigated the mechanisms of inhibitory effect of growth hormone-releasing hormone (GHRH) antagonist JMR-132 on the growth of HT29, HCT-116 and HCT-15 human colon cancer cells in vitro and in vivo. High-affinity binding sites for GHRH and mRNA for GHRH and splice variant-1 (SV1) of the GHRH receptor were found in all three cell lines tested. Proliferation of HT-29, HCT-116 and HCT-15 cells was significantly inhibited in vitro by JMR-132. Time course studies revealed that the treatment of human HCT-116 colon cancer cells with 10 muM GHRH antagonist JMR-132 causes a significant DNA damage as shown by an increase in olive tail moment (OTM) and loss of inner mitochondrial membrane potential (Delta Psi m). Western blotting demonstrated a time-dependent increase in protein levels of phospho-p53 (Ser46), Bax, cleaved caspase-9, -3, cleavage of poly(ADP-ribose)polymerase (PARP) and a decrease in Bcl-2 levels. An augmentation in cell cycle checkpoint protein p21(Waf1/Cip1) was accompanied by a cell cycle arrest in S-phase. DNA fragmentation visualized by the comet assay and the number of apoptotic cells increased time dependently as determined by flow cytometric annexinV and PI staining assays. In vivo, JMR-132 decreased the volume of HT-29, HCT-116 and HCT-15 tumors xenografted into athymic mice up to 75% (p < 0.05) and extended tumor doubling time (p < 0.001). Our observations suggest that GHRH antagonist JMR-132 exerts its antiproliferative effect on experimental colon cancer cells through p21(Waf1/Cip1) mediated S-phase arrest along with apoptosis involving the intrinsic pathway.