Seema Gupta

Phase I safety trial of intravenous ascorbic acid in patients with severe sepsis.

BackgroundParenterally administered ascorbic acid modulates sepsis-induced inflammation and coagulation in experimental animal models. The objective of this randomized, double-blind, placebo-controlled, phase I trial was to determine the safety of intravenously infused ascorbic acid in patients with severe sepsis.MethodsTwenty-four patients with severe sepsis in the medical intensive care unit were randomized 1:1:1 to receive intravenous infusions every six hours for four days of ascorbic acid: Lo-AscA (50xa0mg/kg/24xa0h, nu2009=u20098), or Hi-AscA (200xa0mg/kg/24xa0h, nu2009=u20098), or Placebo (5% dextrose/water, nu2009=u20098). The primary end points were ascorbic acid safety and tolerability, assessed as treatment-related adverse-event frequency and severity. Patients were monitored for worsened arterial hypotension, tachycardia, hypernatremia, and nausea or vomiting. In addition Sequential Organ Failure Assessment (SOFA) scores and plasma levels of ascorbic acid, C-reactive protein, procalcitonin, and thrombomodulin were monitored.ResultsMean plasma ascorbic acid levels at entry for the entire cohort were 17.9u2009±u20092.4xa0μM (normal range 50-70xa0μM). Ascorbic acid infusion rapidly and significantly increased plasma ascorbic acid levels. No adverse safety events were observed in ascorbic acid-infused patients. Patients receiving ascorbic acid exhibited prompt reductions in SOFA scores while placebo patients exhibited no such reduction. Ascorbic acid significantly reduced the proinflammatory biomarkers C-reactive protein and procalcitonin. Unlike placebo patients, thrombomodulin in ascorbic acid infused patients exhibited no significant rise, suggesting attenuation of vascular endothelial injury.ConclusionsIntravenous ascorbic acid infusion was safe and well tolerated in this study and may positively impact the extent of multiple organ failure and biomarkers of inflammation and endothelial injury.Trial registrationClinicalTrials.gov identifier NCT01434121.

Low-Dose Fractionated Radiation Potentiates the Effects of Cisplatin Independent of the Hyper-Radiation Sensitivity in Human Lung Cancer Cells

In this study, the role of hyper-radiation sensitivity (HRS) in potentiating the effects of cisplatin by low-dose fractionated radiation (LDFRT) was evaluated in four human non–small cell lung cancer cell lines. Presence of HRS and cisplatin enhancement ratio (CER) by LDFRT/2 Gy was assessed using colony-forming and apoptotic assays. Cell-cycle disturbances were studied by flow cytometry. Expression of genes involved in apoptosis was assessed using real-time reverse transcriptase PCR arrays. H-157 cells showed a distinct HRS region, followed by UKY-29 and A549 cells, whereas it was absent in H460 cells, which when lack HRS showed maximum CER with LDFRT (4 × 0.5 Gy) both by clonogenic inhibition and by apoptosis compared with single fraction of 2 Gy whereas the most radioresistant A549 cells had the least CER, with no significant differences between LDFRT or 2 Gy. Interestingly, in H-157 cells, a more pronounced CER was observed with LDFRT when assessed by apoptosis but clonogenic inhibition-CER was higher with 2 Gy than with LDFRT. Excluding H-157 cells, the CER by LDFRT was inversely proportional to radioresistance [(determined by D0, the dose to reduce survival by 67% from any point on the linear portion of the survival curve or surviving fraction (SF) at 2 Gy (SF2)] of the cells. LDFRT alone or in combination with cisplatin induced larger number of proapoptotic genes than 2 Gy or cisplatin + 2 Gy in cells showing HRS when compared to H460 cells that lack HRS. These findings indicate that chemopotentiation by LDFRT is correlated more with the intrinsic radiation sensitivity of the non–small lung cancer cells than the HRS phenomenon whereas the mode of cell killing is both through apoptosis and clonogenic inhibition. Mol Cancer Ther; 10(2); 292–302. ©2011 AACR.

Enhancement of radiation and chemotherapeutic drug responses by 2-deoxy-D-glucose in animal tumors

The development of an approach based on the energy-linked modification of DNA repair and cellular recovery processes using 2-deoxy-D-glucose (2-DG; inhibitor of glycolytic ATP production) has shown promising results in a number of model systems of cancer. Following encouraging results on the tolerance and toxicity (acute as well as late effects) of the combination (2-DG and hypofractionated radiotherapy) in Phase I and II clinical trials, its efficacy is currently under evaluation in Phase III clinical trials for glioma patients. Since heterogeneous physiologic and metabolic status in tumors as well as host-tumor interactions influence the local tumor control, which coupled with systemic disturbances could determine the cure (long-term tumor free survival), investigations on the in vivo responses of tumors to the combined treatment have received considerable attention. This communication provides a brief overview on the in vivo studies related to radio- and chemosensitization of tumors by 2-DG, besides the normal tissue toxicity induced by the combined treatment of 2-DG and radiation or chemotherapeutic drugs.

In vitro and in vivo targeted delivery of photosensitizers to the tumor cells for enhanced photodynamic effects

BACKGROUNDnEfficacy of photodynamic therapy can be enhanced by improving uptake, localization, and sub-cellular localization of sensitizers at the sensitive targets.nnnMATERIALS AND METHODSnUptake, localization, and photodynamic effects of hematoporphyrin derivative (HpD, Photosan-3; PS-3) and disulfonated aluminum phthalocyanine (AlPcS₂) were studied either encapsulated in liposomes or conjugated to a monoclonal antibody to carcinoembryonic antigen (anti-CEA) in a brain glioma cell line, BMG-1.nnnRESULTSnAlthough the total uptake with encapsulated or conjugated sensitizers was less than the free sensitizers, photodynamic efficiency was higher due to the localization of the sensitizer at the sensitive targets. Biodistribution of intravenously administered technetium (⁹⁹m Tc)-labeled PS-3 analyzed by gamma camera imaging showed maximum accumulation in the liver followed by tumor. Tumor/muscle (T/N) ratio of free PS-3 was higher compared to encapsulated or conjugated PS-3 but the accumulation of PS-3 significantly reduced in brain and cutaneous tissue following modulated delivery. Pharmacokinetics suggested faster accumulation of encapsulated and conjugated PS-3 in the tumor.nnnCONCLUSIONnLocalization of sensitizers at sensitive targets and reduced accumulation in normal tissues with liposome encapsulation and antibody conjugation suggest that these two delivery systems can potentially enhance the efficacy of photodynamic treatment.

A Realistic Utilization of Nanotechnology in Molecular Imaging and Targeted Radiotherapy of Solid Tumors

Precise dose delivery to malignant tissue in radiotherapy is of paramount importance for treatment efficacy while minimizing morbidity of surrounding normal tissues. Current conventional imaging techniques, such as magnetic resonance imaging (MRI) and computerized tomography (CT), are used to define the three-dimensional shape and volume of the tumor for radiation therapy. In many cases, these radiographic imaging (RI) techniques are ambiguous or provide limited information with regard to tumor margins and histopathology. Molecular imaging (MI) modalities, such as positron emission tomography (PET) and single photon-emission computed-tomography (SPECT) that can characterize tumor tissue, are rapidly becoming routine in radiation therapy. However, their inherent low spatial resolution impedes tumor delineation for the purposes of radiation treatment planning. This review will focus on applications of nanotechnology to synergize imaging modalities in order to accurately highlight, as well as subsequently target, tumor cells. Furthermore, using such nano-agents for imaging, simultaneous coupling of novel therapeutics including radiosensitizers can be delivered specifically to the tumor to maximize tumor cell killing while sparing normal tissue.

Metabolic Cooperation and Competition in the Tumor Microenvironment: Implications for Therapy

The tumor microenvironment (TME) is an ensemble of non-tumor cells comprising fibroblasts, cells of the immune system, and endothelial cells, besides various soluble secretory factors from all cellular components (including tumor cells). The TME forms a pro-tumorigenic cocoon around the tumor cells where reprogramming of the metabolism occurs in tumor and non-tumor cells that underlies the nature of interactions as well as competitions ensuring steady supply of nutrients and anapleoretic molecules for the tumor cells that fuels its growth even under hypoxic conditions. This metabolic reprogramming also plays a significant role in suppressing the immune attack on the tumor cells and in resistance to therapies. Thus, the metabolic cooperation and competition among the different TME components besides the inherent alterations in the tumor cells arising out of genetic as well as epigenetic changes supports growth, metastasis, and therapeutic resistance. This review focuses on the metabolic remodeling achieved through an active cooperation and competition among the three principal components of the TME—the tumor cells, the T cells, and the cancer-associated fibroblasts while discussing about the current strategies that target metabolism of TME components. Further, we will also consider the probable therapeutic opportunities targeting the various metabolic pathways as well as the signaling molecules/transcription factors regulating them for the development of novel treatment strategies for cancer.

Influence of Cell Cycle Checkpoints and p53 Function on the Toxicity of Temozolomide in Human Pancreatic Cancer Cells

Background: Though an increased efficacy of carmustine and temozolomide (TMZ) has been demonstrated by inactivation of O6-methylguanine-DNA methyltransferase (MGMT) with O6-benzyl-guanine (BG) in human pancreatic tumors refractive to alkylating agents, the regulatory mechanisms have not been explored. Methods: The effects of TMZ and BG on apoptosis, cell growth, the mitotic index, cell cycle distribution, and protein expression were studied by TUNEL, cell counting, flow cytometry, and Western blot analysis, respectively. Results: The wt-p53 human pancreatic tumor cell line Capan-2 and p53-efficient mouse embryonic fibroblasts (MEFs) were more responsive to treatment with TMZ + BG than mutant p53 Capan-1 and p53-null MEFs. S phase delay with a subsequent G2/M arrest was observed in Capans in response to BG + TMZ. The G1-to-S transition delay in Capan-2 was associated with p53-dependent apoptosis and was distinctly different from the presumed mismatch repair (MMR) killing operative during the G2/M arrest. The effect of p53 on BG + TMZ toxicity was supported by a marked change in apoptosis when p53 function was restored/inactivated. There was an early induction of MMR proteins in p53-efficient lines. Conclusion: p53 provokes a classic proapoptotic response by delaying G1-to-S progression, but it may also facilitate cell killing by enhancing MMR-related cell cycle arrest and cell death.

Improved Targeting of Photosensitizers by Intratumoral Administration of Immunoconjugates

Biodistribution of technetium (99m Tc) labeled hematoporphyrin derivative (HpD, Photosan-3) conjugated to a monoclonal antibody to carcinoembryonic antigen (anti-CEA) was compared following intravenous (i.v.) and intratumoral (i.t.) administration in solid Ehrlich ascites tumor bearing mice. Images of mice at different time intervals were acquired after injection of radiolabeled PS-3 in either conjugated or unconjugated forms. Quantitative estimation of the radiolabel in different tissues was performed by selecting the different region of interests (ROIs). Maximum accumulation of both free and antibody conjugated PS-3 following i.v. administration was observed in liver followed by tumor. Tumor/muscle (T/N) ratio was more with free PS-3 compared to conjugated PS-3. Pharmacokinetics of free and conjugated PS-3 was also different with faster accumulation of conjugated PS-3 in the tumor. With intratumoral administration of anti-CEA-PS-3-99m Tc, specific accumulation and retention of the sensitizer was observed in the tumor tissue. Since, direct injection of antibody conjugated photosensitizer into the tumor resulted in longer retention of the dye in the tumor with no accumulation in the normal tissues, the present results imply that the toxicity to normal tissues could be reduced significantly with selective destruction of the tumor following photodynamic treatment with the use of i.t. administration of specific antibodies conjugated to photosensitizers.

Non-monotonic changes in clonogenic cell survival induced by disulphonated aluminum phthalocyanine photodynamic treatment in a human glioma cell line

BackgroundPhotodynamic therapy (PDT) involves excitation of sensitizer molecules by visible light in the presence of molecular oxygen, thereby generating reactive oxygen species (ROS) through electron/energy transfer processes. The ROS, thus produced can cause damage to both the structure and the function of the cellular constituents resulting in cell death. Our preliminary investigations of dose-response relationships in a human glioma cell line (BMG-1) showed that disulphonated aluminum phthalocyanine (AlPcS2) photodynamically induced loss of cell survival in a concentration dependent manner up to 1 μM, further increases in AlPcS2concentration (>1 μM) were, however, observed to decrease the photodynamic toxicity. Considering the fact that for most photosensitizers only monotonic dose-response (survival) relationships have been reported, this result was unexpected. The present studies were, therefore, undertaken to further investigate the concentration dependent photodynamic effects of AlPcS2.MethodsConcentration-dependent cellular uptake, sub-cellular localization, proliferation and photodynamic effects of AlPcS2 were investigated in BMG-1 cells by absorbance and fluorescence measurements, image analysis, cell counting and colony forming assays, flow cytometry and micronuclei formation respectively.ResultsThe cellular uptake as a function of extra-cellular AlPcS2 concentrations was observed to be biphasic. AlPcS2 was distributed throughout the cytoplasm with intense fluorescence in the perinuclear regions at a concentration of 1 μM, while a weak diffuse fluorescence was observed at higher concentrations. A concentration-dependent decrease in cell proliferation with accumulation of cells in G2+M phase was observed after PDT. The response of clonogenic survival after AlPcS2-PDT was non-monotonic with respect to AlPcS2 concentration.ConclusionsBased on the results we conclude that concentration-dependent changes in physico-chemical properties of sensitizer such as aggregation may influence intracellular transport and localization of photosensitizer. Consequent modifications in the photodynamic induction of lesions and their repair leading to different modes of cell death may contribute to the observed non-linear effects.

Prognostics of Cyclin-D1 expression with chemoradiation response in patients of locally advanced oral squamous cell carcinoma.

OBJECTIVEnCyclin-D1 has been strongly implicated in cell cycle proliferation particularly in the G1/S checkpoint in the cell cycle, and prognosis in many human malignancies. The present study evaluates its prognostic significance with chemoradiation response in patients of locally advanced oral squamous cell carcinoma (OSCC).nnnMATERIALS AND METHODSnA total of 97 OSCC patients (females = 19 and males = 78), aged 20-67 years and stage III/IV were recruited. Treatment response was assessed according to World Health Organization criteria. Cyclin-D1 expression in tumor tissue was estimated by immunohistochemical method and quantified as percentage positive nuclei.nnnRESULTSnThe Cyclin-D1 expression showed significant (P < 0.01 or P < 0.001) association with tumor size, lymph node status, and clinical stage. After chemoradiation, there were 53.6% complete response (CR) and 34.0% partial response (PR) in primary tumor, and 49.5% CR and 39.2% PR in lymph node; giving an overall response rate of 85.6%. Further, the mean Cyclin-D1 expression showed significant (P < 0.05 or P < 0.001) and inverse association with chemoradiation responses (tumor size, lymph node status and overall treatment response). The 2-year progression-free and overall survival (OS) was 95.89% and 83.31% respectively. Multivariate Cox regression analysis found site of primary tumor, clinical stage, and Cyclin-D1 expression the significant (P < 0.05 or P < 0.01) and independent prognostic markers of OS and among these Cyclin-D1 expression showed the worst prognosis. The high Cyclin-D1 expression (>50%) also showed significantly lower survival in OSCC patients when compared with those had low (<10%) and moderate expressions (10-50%) (Logrank test: χ(2) = 44.42, P < 0.001).nnnCONCLUSIONnThe high Cyclin-D1 expression may serve as a poor prognostic marker in OSCC.