Therapeutic Potential of Medicinal Plant Proteins: Present Status and Future Perspectives.

Biologically active molecules obtained from plant sources, mostly including secondary metabolites, have been considered to be of immense value with respect to the treatment of various human diseases. However, some inevitable limitations associated with these secondary metabolites like high cytotoxicity, low bioavailability, poor absorption, low abundance, improper metabolism, etc., have forced the scientific community to explore medicinal plants for alternate biologically active molecules. In this context, therapeutically active proteins/peptides from medicinal plants have been promoted as a promising therapeutic intervention for various human diseases. A large number of proteins isolated from the medicinal plants have been shown to exhibit anti-microbial, anti-oxidant, anti-HIV, anticancerous, ribosome-inactivating and neuro-modulatory activities. Moreover, with advanced technological developments in the medicinal plant research, medicinal plant proteins such as Bowman-Birk protease inhibitor and Mistletoe Lectin-I are presently under clinical trials against prostate cancer, oral carcinomas and malignant melanoma. Despite these developments and proteins being potential drug candidates, to date, not a single systematic review article has documented the therapeutical potential of the available biologically active medicinal plant proteome. The present article was therefore designed to describe the current status of the therapeutically active medicinal plant proteins/peptides vis-à-vis their potential as future protein-based drugs for various human diseases. Future insights in this direction have also been highlighted.

Ten-Day Quadruple Therapy Comprising Low-Dose Rabeprazole, Bismuth, Amoxicillin, and Tetracycline Is an Effective and Safe First-Line Treatment for Helicobacter pylori Infection in a Population with High Antibiotic Resistance: a Prospective, Multicenter, Randomized, Parallel-Controlled Clinical Trial in China.

The objective of this study was to investigate the efficacy and safety of 10-day bismuth quadruple therapy with amoxicillin, tetracycline, or clarithromycin and different doses of rabeprazole for first-line treatment of Helicobacter pylori infection. This multicenter, randomized, parallel-controlled clinical trial was conducted between March 2013 and August 2014. A total of 431 H. pylori-infected patients with duodenal ulcers were enrolled and randomized into four treatment groups (1:1:1:1) for 10 days, as follows: (i) a group receiving a low dose of rabeprazole of 10 mg twice a day (b.i.d.) (LR dose) plus bismuth, amoxicillin, and clarithromycin (LR-BAC); (ii) a group receiving LR plus bismuth, amoxicillin, and tetracycline (LR-BAT); (iii) a group receiving a high dose of rabeprazole of 20 mg b.i.d. (HR dose) plus bismuth, amoxicillin, and clarithromycin (HR-BAC); and (iv) a group receiving HR-BAT. Antimicrobial susceptibility was assessed by the Etest method. The primary outcome was H. pylori eradication at 4 weeks after the treatment. The per-protocol (PP) eradication rates in the LR-BAC, LR-BAT, HR-BAC, and HR-BAT groups were 94.1%, 91.9%, 94.8%, and 91.9%, respectively, while the intention-to-treat (ITT) eradication rates in those groups were 87.2%, 87.2%, 87.7%, and 86%, respectively. There was no significant difference between the four groups in PP analysis (P = 0.799) and ITT analysis (P = 0.985). The efficacies of four-treatment therapy were not affected by antibiotic resistance. The adverse events in the four treatment groups were similar; central nervous system (CNS) and gastrointestinal symptoms were the most common reported. Bismuth-containing quadruple therapy with low-dose rabeprazole, amoxicillin, and tetracycline is a good option for first-line treatment of H. pylori infection in a population with high antibiotic resistance. (This study is registered at Chinese Clinical Trials Registry [www.chictr.org.cn] under number ChiCTR1800014832.).

Linezolid Dose That Maximizes Sterilizing Effect While Minimizing Toxicity and Resistance Emergence for Tuberculosis.

Linezolid has an excellent sterilizing effect in tuberculosis patients but high adverse event rates. The dose that would maximize efficacy and minimize toxicity is unknown. We performed linezolid dose-effect and dose-scheduling studies in the hollow fiber system model of tuberculosis (HFS-TB) for sterilizing effect. HFS-TB units were treated with several doses to mimic human-like linezolid intrapulmonary pharmacokinetics and repetitively sampled for drug concentration, total bacterial burden, linezolid-resistant subpopulations, and RNA sequencing over 2 months. Linezolid-resistant isolates underwent whole-genome sequencing. The expression of genes encoding efflux pumps in the first 1 to 2 weeks revealed the same exposure-response patterns as the linezolid-resistant subpopulation. Linezolid-resistant isolates from the 2nd month of therapy revealed mutations in several efflux pump/transporter genes and a LuxR-family transcriptional regulator. Linezolid sterilizing effect was linked to the ratio of unbound 0- to 24-h area under the concentration-time curve (AUC0-24) to MIC. Optimal microbial kill was achieved at an AUC0-24/MIC ratio of 119. The optimal sterilizing effect dose for clinical use was identified using Monte Carlo simulations. Clinical doses of 300 and 600 mg/day (or double the dose every other day) achieved this target in 87% and >99% of 10,000 patients, respectively. The susceptibility breakpoint identified was 2 mg/liter. The simulations identified that a 300-mg/day dose did not achieve AUC0-24s associated with linezolid toxicity, while 600 mg/day achieved those AUC0-24s in <20% of subjects. The linezolid dose of 300 mg/day performed well and should be compared to 600 mg/day or 1,200 mg every other day in clinical trials.

Linezolid: a promising option in the treatment of Gram-positives.

Linezolid, an oxazolidinone antimicrobial agent that acts by inhibiting protein synthesis in a unique fashion, is used in the treatment of community-acquired pneumonia, skin and soft-tissue infections and other infections caused by Gram-positive bacteria including VRE and methicillin-resistant staphylococci. Currently, linezolid resistance among these pathogens remains low, commonly <1.0%, although the prevalence of antibiotic resistance is increasing in many countries. Therefore, the development of resistance by clinical isolates should prompt increased attention of clinical laboratories to routinely perform linezolid susceptibility testing for this important agent and should be taken into account when considering its therapeutic use. Considering the importance of linezolid in the treatment of infections caused by Gram-positive bacteria, this review was undertaken to optimize the clinical use of this antibiotic.

Fusidic Acid: A Bacterial Elongation Factor Inhibitor for the Oral Treatment of Acute and Chronic Staphylococcal Infections.

Fusidic acid is an oral antistaphylococcal antibiotic that has been used in Europe for more than 40 years to treat skin infections as well as chronic bone and joint infections. It is a steroidal antibiotic and the only marketed member of the fusidane class. Fusidic acid inhibits protein synthesis by binding EF-G-GDP, which results in the inhibition of both peptide translocation and ribosome disassembly. It has a novel structure and novel mode of action and, therefore, there is little cross-resistance with other known antibiotics. Many mutations can occur in the FusA gene that codes for EF-G, and some of these mutations can result in high-level resistance (minimum inhibitory concentration [MIC] > 64 mg/L), whereas others result in biologically unfit staphylococci that require compensatory mutations to survive. Low-level resistance (<8 mg/L) is more common and is mediated by fusB, fusC, and fusD genes that code for small proteins that protect EF-G-GDP from binding fusidic acid. The genes for these proteins are spread by plasmids and can be selected mostly by topical antibiotic use. Reports of resistance have led to combination use of fusidic acid with rifampin, which is superseded by the development of a new dosing regimen for fusidic acid that can be used in monotherapy. It consists of a front-loading dose to decrease the potential for resistance development followed by a maintenance dose. This dosing regimen is now being used in clinical trials in the United States for skin and refractory bone and joint infections.

Clarithromycin regresses endometriotic implants in rat endometriosis model.

The aim of this study was to investigate the effect of clarithromycin in rat endometriosis and its association with matrix metalloproteinase-9 (MMP-9) expression. After surgical induction of endometriosis, 27 rats were randomised into three groups. Size of endometriotic implants were evalutated and rats in group I (n = 9) were given 100 mg/kg/day of oral clarithromycin, rats in group II (n = 9) were given single 1 mg/kg s.c. injection of leuprolide acetate and rats in group III (n = 9) were not given any medication for 21 days. At the end of 21 days of medication, remaining 23 rats were sacrificed to evaluate morphological and histological features of implants. There was a significant difference between the groups in implant volumes (p = 0.004) before and after medication. Regression of implants were significantly higher in groups I and II than that in control group (p = 0.009 and p = 0.011, respectively). After medication, in group I the implant volume decreased from 62 (12-166) mm(3) to 26 (3-87) mm(3) (p = 0.012) and in group II the volume decreased from 224 (76-1135) mm(3) to 62 (26-101) mm(3) (p = 0.028). There was a significant difference between groups in histopathological score (p = 0.024). The epithelial immunohistochemical score of MMP-9 was significantly lower in group II than that in control group (p = 0.014). In conclusion, clarithromycin regresses endometriotic implants in rats, but not via MMP-9.

RX-P873, a Novel Protein Synthesis Inhibitor, Accumulates in Human THP-1 Monocytes and Is Active against Intracellular Infections by Gram-Positive (Staphylococcus aureus) and Gram-Negative (Pseudomonas aeruginosa) Bacteria.

The pyrrolocytosine RX-P873, a new broad-spectrum antibiotic in preclinical development, inhibits protein synthesis at the translation step. The aims of this work were to study RX-P873's ability to accumulate in eukaryotic cells, together with its activity against extracellular and intracellular forms of infection by Staphylococcus aureus and Pseudomonas aeruginosa, using a pharmacodynamic approach allowing the determination of maximal relative efficacies (Emax values) and bacteriostatic concentrations (Cs values) on the basis of Hill equations of the concentration-response curves. RX-P873's apparent concentration in human THP-1 monocytes was about 6-fold higher than the extracellular one. In broth, MICs ranged from 0.125 to 0.5 mg/liter (S. aureus) and 2 to 8 mg/liter (P. aeruginosa), with no significant shift in these values against strains resistant to currently used antibiotics being noted. In concentration-dependent experiments, the pharmacodynamic profile of RX-P873 was not influenced by the resistance phenotype of the strains. Emax values (expressed as the decrease in the number of CFU from that in the initial inoculum) against S. aureus and P. aeruginosa reached more than 4 log units and 5 log units in broth, respectively, and 0.7 log unit and 2.7 log units in infected THP-1 cells, respectively, after 24 h. Cs values remained close to the MIC in all cases, making RX-P873 more potent than antibiotics to which the strains were resistant (moxifloxacin, vancomycin, and daptomycin for S. aureus; ciprofloxacin and ceftazidime for P. aeruginosa). Kill curves in broth showed that RX-P873 was more rapidly bactericidal against P. aeruginosa than against S. aureus. Taken together, these data suggest that RX-P873 may constitute a useful alternative for infections involving intracellular bacteria, especially Gram-negative species.

Management of hepatic encephalopathy in the hospital.

Hepatic encephalopathy (HE) develops in up to 50% of patients with cirrhosis and is a feature of decompensated cirrhosis. With the goal of reviewing the evidence for treatment and prevention of overt hepatic encephalopathy, pubmed was searched using search terms hepatic encephalopathy AND treatment, limited to human studies from January 1, 2003, through December 1, 2013, and supplemented by key references. The inpatient incidence of HE is approximately 23,000 annually, and management of these patients is common for internists and subspecialists. Treatment of the hospitalized patient with HE has changed in recent years. Treatment entails 2 phases: induction and maintenance of remission. Most cases of significant HE are precipitated by infection, gastrointestinal bleeding, medications, or other culprits. All patients should be evaluated for secondary triggers of HE, and treatment should be initiated with a nonabsorbable disaccharide (ie, lactulose) in most patients. Rifaximin (off label) can be added in patients not responding to lactulose. Neomycin is a less preferred alternative to rifaximin owing to its adverse effect profile. Other therapies, including zinc, L-ornithine-L-aspartate, and branched-chain amino acids, can be considered for patients not responding to disaccharides and nonabsorbable antibiotics. Large portosystemic shunts may be embolized in patients with medically refractory recurrent or severe HE with otherwise well-compensated cirrhosis. Molecular Adsorbent Recirculating System is now available for patients with severe HE who do not respond to medical therapy. It is critically important that patients hospitalized with significant HE continue maintenance therapy at the time of dismissal to prevent further episodes. Patients with a first-time episode of HE can be administered lactulose, and careful instructions should be provided to patients and caregivers about dose titration to achieve 3 bowel movements daily. Patients with recurrent HE episodes despite lactulose use benefit from the addition of rifaximin, which decreases the frequency of recurrent HE episodes and related hospitalizations. Last, patients and their families should be counseled about the risk of motor vehicle accidents, which require mandatory reporting to the Department of Motor Vehicles in some states.

Will new antimicrobials overcome resistance among Gram-negatives?

The spread of resistance among Gram-positive and Gram-negative bacteria represents a growing challenge for the development of new antimicrobials. The pace of antibiotic drug development has slowed during the last decade and, especially for Gram-negatives, clinicians are facing a dramatic shortage in the availability of therapeutic options to face the emergency of the resistance problem throughout the world. In this alarming scenario, although there is a shortage of compounds reaching the market in the near future, antibiotic discovery remains one of the keys to successfully stem and maybe overcome the tide of resistance. Analogs of already known compounds and new agents belonging to completely new classes of antimicrobials are in early stages of development. Novel and promising anti-Gram-negative antimicrobials belong both to old (cephalosporins, carbapenems, ß-lactamase inhibitors, monobactams, aminoglycosides, polymyxin analogues and tetracycline) and completely new antibacterial classes (boron-containing antibacterial protein synthesis inhibitors, bis-indoles, outer membrane synthesis inhibitors, antibiotics targeting novel sites of the 50S ribosomal subunit and antimicrobial peptides). However, all of these compounds are still far from being introduced into clinical practice. Therefore, infection control policies and optimization in the use of already existing molecules are still the most effective approaches to reduce the spread of resistance and preserve the activity of antimicrobials.

Management of suppurative cervical lymphadenitis in a healthy 24-year-old man.

Unilateral suppurative cervical lymphadenitis is characterized by acute onset of 1 or more tender cervical lymph nodes and can lead to fever, cellulitis, abscess formation, and bacteremia. This form of lymphadenitis is usually caused by gram-positive bacteria. The present case details the treatment of a previously healthy 24-year-old man who presented with an acutely inflamed cervical lymph node. The patient did not respond to antibiotic monotherapy or combination antibiotics but recovered rapidly after methylprednisolone and osteopathic manipulative treatment were added to his care.

The therapeutic potential of fungal ribotoxins.

Ribotoxins constitute a family of toxic extracellular fungal RNases that exert a highly specific activity on a conserved region of the larger molecule of rRNA, known as the sarcin-ricin loop. This cleavage of a single phosphodiester bond inactivates the ribosome and leads to protein synthesis inhibition and cell death. In addition to this ribonucleolytic activity, ribotoxins can cross lipid membranes in the absence of any known protein receptor. This ability is due to their capacity to interact with acid phospholipid-containing membranes. Both activities together explain their cytotoxic character, being rather specific when assayed against some transformed cell lines. The determination of high-resolution structures of some ribotoxins, the characterization of a large number of mutants, and the use of lipid model vesicles and transformed cell lines have been the tools used for the study of their mechanism of action at the molecular level. The present knowledge suggests that wild-type ribotoxins or some modified variants might be used in human therapies. Production of hypoallergenic mutants and immunotoxins designed against specific tumors stand out as feasible alternatives to treat some human pathology in the mid-term future.

[Linezolid: antibacterial activity, clinical efficacy and resistance]. / Le linézolide: activité antibactérienne, intérêts cliniques et résistance.

Linezolid is a synthetic antibiotic, the first available agent in a new class of antibiotic called the oxazolidinones, whose particular mechanism of action consists in inhibiting the initiation of protein synthesis. Its spectrum of in vitro and in vivo activity includes staphylococci, streptococci, enterococci, corynebacteria and some anaerobic bacteria (Peptostreptococcus, Clostridium, and Fusobacterium). The first therapeutic results were very encouraging, leading to the marketing of the product in France in 2002. Linezolid is indicated in the treatment of pneumonia and the complicated infections of the skin. Pharmacocinetics studies have shown that linezolid has an excellent bioavailability allowing a fast relay per os. However, failures of treatment under linezolid were reported and resistant strains of staphylococci and enterococci were obtained in vitro and in vivo after therapeutic use of this antibiotic. Changes in the domain V of 23S rRNA were found in the site of fixation, the most frequent was (G out of U) in position 2576 (numbering E. coli). In a context where resistance to traditional treatments in enterococci, pneumococci and S. aureus do not cease to increase, linezolid can be regarded as a therapeutic alternative to treat the infections with Gram-positive cocci.

Wogonin sensitizes resistant malignant cells to TNFalpha- and TRAIL-induced apoptosis.

TNFalpha has previously been used in anticancer therapy. However, the therapeutic application of TNFalpha was largely limited due to its general toxicity and the fact that it activates the NF-kappaB-family transcription factors, which are proinflammatory and antiapoptotic. To overcome this problem in vitro, specific NF-kappaB inhibitors or transcription or protein synthesis inhibitors such as actinomycin D and cycloheximide are usually used in combination to increase TNFalpha killing of tumor cells. However, these agents also cause harmful side effects in vivo. We show here that wogonin, derived from the popular Chinese herb Huang-Qin, attenuates NF-kappaB activity by shifting TNFalpha-induced free radical .O(2)(-) to a more reduced nonradical product, H(2)O(2), and thereby sensitizes TNFalpha-resistant leukemia cells to TNFalpha-induced apoptosis. Importantly, wogonin does not affect the viability of normal peripheral blood T cells. Wogonin also sensitizes TRAIL-induced apoptosis. Our data suggest a potential use of wogonin as a TNFalpha or TRAIL adjuvant for cancer treatment. Our data also demonstrate how a herbal compound enhances killing of tumor cells with reduced side effects compared with other treatments.

RNA therapeutics directed to the non coding regions of APP mRNA, in vivo anti-amyloid efficacy of paroxetine, erythromycin, and N-acetyl cysteine.

Lead compounds directed to the 5' leader of the Amyloid Precursor Protein transcript (i.e., paroxetine (SSRI), N-acetyl cysteine (antioxidant), and erythromycin (macrolide antibiotic)) were employed in a pilot study to evaluate their anti-amyloid efficacy in the TgCRND8 transgenic mouse model for Alzheimer's Disease (AD). The relative levels of Abeta peptide were reduced after exposure of mice to paroxetine (N=5), NAC (N=7), and erythromycin (N=7) relative to matched placebo counterparts. Paroxetine limited the levels of APP holoprotein and total Abeta peptide levels (measurements of Abeta were performed at two separate sites by quantitative western blotting and ELISA assay). The paroxetine data provided proof-of-concept for our strategy for further screening the APP 5'UTR target to identify novel drugs that exhibit anti-amyloid efficacy in vivo. Erythromycin and azithromycin were macrolide antibiotics that markedly changed the cleavage of the APP C-Terminal Fragment (CTF) in SH-SY5Y cells. Erythromycin provided orally to TgCRND8 mice consistently (100%) reduced brain Abeta(1-42) levels. These data demonstrated a highly statistically significant anti-amyloid trend for paroxetine, NAC and erythromycin. The potential for conducting further studies with these compounds using larger cohorts of TgCRND8 mice is discussed, particularly since erythromycin has recently been exposed to mice for a further 6 months (N=6). It will be possible to employ the chemical structures of paroxetine and erythromycin as starting points for drug design and development for AD therapeutics.

Effect of therapeutic moderate hypothermia on multi-drug resistance protein 1-mediated transepithelial transport of drugs.

To clarify the effect of therapeutic moderate hypothermia on drug distribution, transepithelial transport via multi-drug resistance protein 1 (MDR1) (also called P-glycoprotein or ABCB1) was evaluated at various temperatures in vitro using LLC-GA5-COL150 cells, which were established by transfecting human MDR1 complementary deoxyribonucleic acid into kidney epithelial LLC-PK(1) cells and express MDR1 on the apical membrane. MDR1 is expressed in the blood-brain barrier to limit drug distribution to the brain by exporting exogenous substances including calcium blockers and antiarrhythmic drugs. Digoxin was used as a typical substrate, as well as the non-substrate tetracycline and paracellular marker inulin. MDR1-mediated transport of digoxin decreased at lower temperatures. Transport of tetracycline also decreased at lower temperatures, probably due to changes in membrane fluidity. However, no change was found at over 32 degrees C, suggesting that passive diffusion does not change during moderate hypothermia. The distribution of MDR1 substrates should be considered during hypothermic conditions, as the clinical outcome could be affected.

Identification of candidate drugs for the treatment of ALS.

A consortium of investigators interested in neurodegenerative diseases collaborated to screen 1040 drugs in multiple neurodegenerative disease assays. One model of amyotrophic lateral sclerosis (ALS) pathogenesis in particular incorporated glutamate exposure in enriched primary rat motor neuron cultures. In this model 78 compounds decreased motor neuron death caused by 100 microM glutamate. Almost all these pharmacological agents act at one or more of the following cellular targets: 1) protein synthesis inhibition; 2) Cox inhibition; 3) regulation of anion flux; 4) modulation of GABA receptors; 5) antioxidant, and 6) cell cycle inhibition. The most prevalent mode of action was the regulation of intracellular calcium. These data extend the understanding of motor neuron degeneration and identify a number of cellular targets for the improvement of combined therapies for neurodegenerative disease.

[Evaluation of Helicobacter pylori susceptibility to rifaximin]. / Evaluación de la susceptibilidad de Helicobacter pylori a la rifaximina.

INTRODUCTION: Helicobacter pylori infection affects more than half the world's population. It is a major cause of chronic gastritis and there is a strong association with peptic ulceration and gastric adenocarcinoma. Rifaximin is a new nonabsorbable broad-spectrum antimicrobial agent that reaches high concentrations in the gastrointestinal tract. AIM: To evaluate the in vitro activity of rifaximin against H. pylori isolates. METHODS: Thirty-one H. pylori strains were analyzed by the agar dilution method. Clarithromycin was used as the control antibiotic. Staphylococcus aureus and Streptococcus pneumoniae were used as quality control strains. Plates were read at days 4 and 7 of incubation. The MIC50 and MIC90 of each antibiotic were calculated. Strains with a clarithromycin MIC of > 1 microg/ml were considered resistant. RESULTS: The MIC50 of clarithromycin at days 4 and 7 was 0.125 microg/ml and the MIC90 at days 4 and 7 ranged from 8 to 16 microg/ml, respectively. The MIC50 of rifaximin at days 4 and 7 ranged from 1 to 2 microg/ml, respectively, and the MIC90 was 4 microg/ml at both days 4 and 7. Twenty percent of H. pylori strains were resistant to clarithromycin. All clarithromycin-resistant strains were inhibited at a maximal rifaximin concentration of 4 microg/ml. CONCLUSION: These results indicate that this new antibiotic may be useful for eradication of H. pylori infection. Because rifaximin is active against H. pylori strains resistant to clarithromycin, it could be useful in combination with this drug or in the treatment of therapeutic failure.

FDA-preapproved drugs targeted to the translational regulation and processing of the amyloid precursor protein.

The 5' untranslated region (5'UTR) of the transcript encoding the Alzheimer's amyloid precursor protein (APP) is a key regulatory sequence that determines the amount of intracellular APP holoprotein present in brain derived cells. Using neuroblastoma cells (SY5Y) we developed a transfection based screen of a library of FDA drugs to identify compounds that limited APP luciferase reporter expression translated from the APP 5'UTR. Paroxetine (Paxil trade mark ), dimercaptopropanol, phenserine, desferrioxamine, tetrathiolmobdylate, and azithromycin were six leads that were subsequently found to also suppress APP holoprotein levels or to alter APP cleavage (azithromycin). Since APP holoprotein levels are proportionate to Abeta peptide output in many systems we tested the efficacy of paroxetine and dimercaptopropanol to limit Abeta secretion as measured by ELISA assays. Paroxetine and dimercaptopropanol limited Abeta peptide secretion from lens epithelial cells (B3 cells). Interestingly, paroxetine changed the steady-state levels of transferrin receptor mRNAs. These data suggested that this serotonin reuptake inhibitor (SSRI) provided extra pharmacological action to chelate interacellular iron or change the intracellular iron distribution. An altered iron distribution would be predicted to indirectly limit APP holoprotein expression and Abeta peptide secretion.

Autologous blood cell transplantation in multiple myeloma: impact of CD34+ cell selection with long follow-up.

Positive CD34(+) selection to purge blood cell harvests is one way to attempt to reduce the high relapse risk after high-dose chemotherapy (HDT) supported by autologous blood cell transplantation (ABCT) in patients with multiple myeloma (MM). Until recently, however, the impact of CD34(+) selection, if any, on long-term clinical outcome in MM has remained obscure. We have analyzed engraftment kinetics, response to HDT, progression-free survival (PFS), and overall survival (OS) for 64 consecutive MM patients who have been treated with up-front HDT plus ABCT at our institution between 1993 and 1998. Nonrandomized comparisons were made between transplants with unselected (39 patients) and CD34(+)-selected (25 patients) grafts. The engraftment kinetics, need of blood product support, discharge time from hospital, and response to HDT were similar for both unselected and selected transplants. The median PFS was also similar (26 and 30 months, respectively) for the both groups. With a median follow-up time for the survivors of 67.5 months, the median OS (78 and 75 months, respectively) did not differ between transplants with unselected and selected grafts. In conclusion, this nonrandomized study suggests that positive CD34(+) selection has no beneficial impact on long-term outcome of patients with MM.

Sensitization of human colon cancer cells to TRAIL-mediated apoptosis.

TNF-related apoptosis-inducing ligand (TRAIL), a novel member of the tumor necrosis factor (TNF) family, is thought to induce apoptosis preferentially in cancer cells; however, increasing evidence suggests that a number of cancers are resistant to TRAIL treatment. FLICE-like inhibitory protein (FLIP), which structurally resembles caspase-8, can act as an inhibitor of apoptosis when expressed at high levels in certain cancer cells. The purpose of our present study was to determine whether human colon cancer cells are sensitive to TRAIL treatment and, if not, to identify potential mechanisms of resistance. Colon cancer cells of different metastatic potential (KM12C, KML4A, and KM20) were found to be resistant to the effects of TRAIL when used as a single agent. FLIP expression levels were increased in all three KM cell lines. Treatment with either actinomycin D (Act D;10 :g/ml) or cycloheximide (CHX; 10 :g/ml) decreased FLIP expression levels in all three cell lines. The decrease in cellular levels of FLIP was associated with sensitization to TRAIL-mediated apoptosis, as demonstrated by enhanced cell death and caspase-3 activity compared with either Act D or CHX alone. Our findings suggest that reduction of FLIP levels by Act D or CHX renders TRAIL-resistant human colon cancer cells sensitive to TRAIL-mediated apoptosis. The combination of TRAIL along with agents such as Act D or CHX, which target proteins that prevent cell death, may provide a more effective and less toxic regimen for treatment of resistant colon cancers.