Exploring the possibility of drug repurposing for cancer therapy targeting human lactate dehydrogenase A: a computational approach.

Human lactate dehydrogenase A (LDHA) is an anaerobic glycolytic enzyme involved in the inter-conversion of pyruvate to lactate. The level of LDHA in various types of cancer cells is found to be elevated and the dependence of cancer cells on anaerobic glycolysis is viewed as the reason for this elevation. Moreover, inhibition of LDHA activity has been shown to be effective in impairing the growth of tumors, making the LDHA as a potential target for cancer therapy. In this computational study, we have performed a pharmacophore based screening of approved drugs followed by a molecular docking based screening to find a few potential LDHA inhibitors. Molecular dynamics simulations have also been performed to examine the stability of the LDHA-drug complexes as obtained from the docking study. The result of the study showed that darunavir, moxalactam and eprosartan can bind to the active site of LDHA with high affinity in comparison to two known synthetic inhibitors of LDHA. The results of the molecular dynamics simulation showed that these drugs can bind stably with the enzyme through hydrogen bond and hydrophobic interactions. Hence, it is concluded that darunavir, moxalactam and eprosartan may be considered as potential inhibitors of LDHA and can be used for cancer therapy after proper validation of their effectiveness through in vitro, in vivo and clinical trials.Communicated by Ramaswamy H. Sarma.

Latamoxef induced a severe coagulation disorder in older patients in China: Two case reports.

WHAT IS KNOWN AND OBJECTIVE: We present two cases of severe coagulation disorders induced by latamoxef, thereby revealing risk factors of coagulation disorder in latamoxef-treated patients. CASE SUMMARY: Two very elderly patients developed haemorrhage, and coagulation tests showed a longer prothrombin time (PT), activated partial thromboplastin time (APTT) and a high international normalized ratio (INR). Latamoxef was thought to be responsible for the coagulopathy in these patients, and coagulation disorder was relieved after vitamin-K intake. WHAT IS NEW AND CONCLUSION: We report on two cases of coagulopathy in patients given latamoxef. Advanced age, deficiency in vitamin-K intake, poor nutritional status, abnormal coagulation history, ongoing anti-coagulation/anti-aggregation therapy, renal dysfunction and polypharmacy are possible contributory factors, and should be looked out for when prescribing latamoxef.

The combination of salvianolic acid A with latamoxef completely protects mice against lethal pneumonia caused by methicillin-resistant Staphylococcus aureus.

Staphylococcus aureus (S. aureus), especially methicillin-resistant Staphylococcus aureus (MRSA), is a major cause of pneumonia, resulting in severe morbidity and mortality in adults and children. Sortase A (SrtA), which mediates the anchoring of cell surface proteins in the cell wall, is an important virulence factor of S. aureus. Here, we found that salvianolic acid A (Sal A), which is a natural product that does not affect the growth of S. aureus, could inhibit SrtA activity (IC50 = 5.75 µg/ml) and repress the adhesion of bacteria to fibrinogen, the anchoring of protein A to cell wall, the biofilm formation, and the ability of S. aureus to invade A549 cells. Furthermore, in vivo studies demonstrated that Sal A treatment reduced inflammation and protected mice against lethal pneumonia caused by MRSA. More significantly, full protection (a survival rate of 100%) was achieved when Sal A was administered in combination with latamoxef. Together, these results indicate that Sal A could be developed into a promising therapeutic drug to combat MRSA infections while limiting resistance development.

Lysis-deficient bacteriophage therapy decreases endotoxin and inflammatory mediator release and improves survival in a murine peritonitis model.

BACKGROUND: Lysis-deficient (LyD) bacteriophages (phages) kill bacteria without endotoxin (Et) release. This may minimize systemic cytokine responses and limit inflammation in bacterial sepsis. We determined the effects of t amber A3 T4 LyD and virulent wild-type (WT) phages on mouse bacterial peritonitis. METHODS: Balb/c mice were injected with B40sul Escherichia coli, treated intraperitoneally with LyD, WT, or a beta-lactam antibiotic [latamoxef sodium (LMOX)], and followed for survival. We measured Et release, tumor necrosis factor (TNF)-alpha and interleukin (IL)-6, as well as bacterial counts and peritoneal exudative cells (PECs) in peritoneal lavage fluid at 6 and 12 hours after infection. RESULTS: LyD mice showed significantly greater survival compared with other groups. Et levels were significantly lower in the LyD mice at 6 and 12 hours after infection. TNF-alpha and IL-6 levels were lower in LyD mice compared with control (untreated) mice at 12 hours. Compared with controls, bacteria counts in peritoneal lavage fluid were lower in all treatment groups (LyD, WT, or LMOX) at 6 and 12 hours. PEC counts were highest in LyD mice at 6 hours but significantly lower than that in WT phage- and LMOX-treated mice at 12 hours. CONCLUSIONS: LyD phage therapy significantly improves survival and attenuates the systemic effects of bacterial sepsis by minimizing Et release and pro-inflammatory mediators in murine bacterial peritonitis. Further studies may find phage therapy useful in treating peritonitis and multidrug-resistant bacterial infections.

Inactivation of Aeromonas hydrophila metallo-beta-lactamase by cephamycins and moxalactam.

Incubation of moxalactam and cefoxitin with the Aeromonas hydrophila metallo-beta-lactamase CphA leads to enzyme-catalyzed hydrolysis of both compounds and to irreversible inactivation of the enzyme by the reaction products. As shown by electrospray mass spectrometry, the inactivation of CphA by cefoxitin and moxalactam is accompanied by the formation of stable adducts with mass increases of 445 and 111 Da, respectively. The single thiol group of the inactivated enzyme is no longer titrable, and dithiothreitol treatment of the complexes partially restores the catalytic activity. The mechanism of inactivation by moxalactam was studied in detail. Hydrolysis of moxalactam is followed by elimination of the 3' leaving group (5-mercapto-1-methyltetrazole), which forms a disulfide bond with the cysteine residue of CphA located in the active site. Interestingly, this reaction is catalyzed by cacodylate.

Methicillin-resistant Staphylococcus aureus proliferation in the rat gut is influenced by gastric acid inhibition and the administration of antibiotics.

The author studied methicillin-resistant Staphylococcus aureus (MRSA) proliferation in the rat gut which was influenced by gastric acid inhibition and the administration of antibiotics. When male Wistar rats were bred by total parenteral nutrition (TPN), and were continuously administered famotidine 4 mg/kg per day, the gastric acidity was observed to decrease to pH 6.4+/-0.1. However, when they were bred by TPN, and histamine 4 mg/kg per hour was continuously administered, the gastric acidity was observed to increase to pH 1.9+/-0.4. MRSA was thus able to cross over to the small intestine only during the famotidine medication. If rats were intravenously administered latamoxef (LMOX) after an oral inoculation of MRSA, then the viable MRSA counts in the stomach, small intestine, and large intestine all decreased on day 4. In contrast, if the gastric acidity decreased and the rats were treated by an oral administration of kanamycin and metronidazole before an oral inoculation of MRSA and thereafter were administered LMOX, then the MRSA count significantly increased. It is thus concluded that a suppression of gastric acid and a great disorder of the intestinal flora is indispensable for the colonization of MRSA into the small intestine, while in vitro the propagation of MRSA requires a continuity of suppression absent in the bacterial flora.

Protein carbonyl formation in blood plasma by cephalosporins.

Cephalosporin antibiotics caused the formation of carbonyl groups in the plasma proteins both in vivo and in vitro. After the administration of either moxalactam (3 g/day) or cefotaxime (2 g/day) to patients for 7 days, the carbonyl contents in the plasma proteins increased markedly as determined by the 2,4-dinitrophenylhydrazine (DNPH) method. The increase in protein carbonyl groups was also visualized by the conjugation of plasma proteins with fluorescein thiosemicarbazide (FTSC) and subsequent electrophoresis. When blood plasma was incubated with cephalosporins, most of the cephalosporins tested caused the carbonyl formation in plasma proteins to significant degrees in a concentration-dependent manner. Although a number of plasma proteins and other nonplasma proteins could be modified by cephalosporins in vitro, the plasma albumin was most markedly modified in vivo as well as in vitro. The protein carbonyl formation by cephalosporins was inhibited by ascorbic acid, reduced glutathione, and cysteine, but it was not affected by FeSO4, CuSO4, desferrioxamine, EDTA, catalase, superoxide dismutase, uric acid, alpha-tocopherol, and mannitol. Sodium borohydride, when applied to moxalactam-treated plasma proteins, markedly reduced the reactivities of the protein with FTSC or DNPH, indicating that the observed reactivities of the cephalosporin-treated proteins toward FTSC or DNPH are actually due to the protein carbonyl groups. These data suggest that cephalosporins can oxidatively modify proteins in blood plasma and other tissues and that the oxidative modification of proteins may be involved in the adverse reactions observed frequently following cephalosporin therapy.

Inhibitory effects of antibiotics on platelet aggregation in vitro.

1. We evaluated in vitro inhibitory effects of six types of antibiotic, aztreonam (AZT), cefamandole (CMD), cefmetazole (CMZ), cefotiam (CTM), flomoxef (FMOX) and latamoxef (LMOX), on platelet aggregation, using healthy volunteers' blood. Four types--FMOX, LMOX, CTM and CMD--inhibited, in concentration of 2500 micrograms/ml, the secondary aggregation induced by 3.0 microM adenosine diphosphate (ADP), and also inhibited the aggregation induced by 0.5 micrograms/mi collagen. AZT in the same concentration, did not inhibit the aggregation induced by collagen, and it inhibited only ADP-induced aggregation. CMZ, in the same concentration, inhibited neither of the two aggregations. 2. The inhibitory effects of the antibiotics on collagen-induced aggregation were dependent on the concentration of respective antibiotics. When classified by the strength of inhibitory action, LMOX and FMOX were strong, followed by CTM and CMD. The action of AZT and CMZ was weak. In particular, LMOX showed a 32% inhibitory effect at concentration of 50 micrograms/ml, a level near the blood concentration obtained with clinical usual dose. 3. No relationship was observed between inhibitory effects of antibiotics on ADP- or collagen-induced aggregation and the presence or absence of carboxyl group and/or N-methyltetrazolethiol group in the chemical structure.

Hemophagocytic syndrome associated with Bacteroides fragilis infection in a patient with acute monoblastic leukemia.

The HS has been associated with malignant hemopathies. We report here a case of HS related to Bacteroides fragilis during the course of acute monoblastic leukemia. Evolution was fatal despite remission of the leukemia process and response of the infection to appropriate antibiotic therapy.

E5531, a pure endotoxin antagonist of high potency.

Shock due to Gram-negative bacterial sepsis is a consequence of acute inflammatory response to lipopolysaccharide (LPS) or endotoxin released from bacteria. LPS is a major constituent of the outer membrane of Gram-negative bacteria, and its terminal disaccharide phospholipid (lipid A) portion contains the key structural features responsible for toxic activity. Based on the proposed structure of nontoxic Rhodobacter capsulatus lipid A, a fully stabilized endotoxin antagonist E5531 has been synthesized. In vitro, E5531 demonstrated potent antagonism of LPS-mediated cellular activation in a variety of systems. In vivo, E5531 protected mice from LPS-induced lethality and, in cooperation with an antibiotic, protected mice from a lethal infection of viable Escherichia coli.

Ceftriaxone versus latamoxef in febrile neutropenic patients: empirical monotherapy in patients with solid tumours.

121 patients with 132 febrile episodes were randomised to ceftriaxone or latamoxef monotherapy in order to compare antibiotic efficacy in neutropenic patients treated with cytotoxic chemotherapy for solid tumours. In 80 evaluable episodes no significant differences were observed between the two groups with respect to efficacy and fatal failure rates. Of episodes treated with ceftriaxone, 67% showed a favourable clinical response vs. 61% in the latamoxef group. The clinical response rates in episodes with documented bacterial infections were 67 and 56% in the two treatment groups. In 18% of the episodes with documented initial infections the patients died of presumably uncontrolled infection. The convenient once daily dosage schedule combined with fewer severe adverse reactions favours the use of ceftriaxone instead of latamoxef. Although a relative high degree of response was seen, empirical antibiotic monotherapy apparently does not offer a sufficient antibacterial cover in infections in this type of patient with defective host immunity.

Detection of antibiotic-induced platelet dysfunction in whole blood using flow cytometry.

Using flow cytometry and activation-dependent monoclonal antibodies, we have developed a technique based on forward angle-light scatter (FALS) and immunofluorescence that simultaneously detects human platelet activation, secretion, and aggregation in whole blood. To detect the effects of cefotetan and latamoxef, both of which contain an N-MTT side chain, and of free N-MTT and cefoxitin, which does not contain the N-MTT side chain, on platelet activation and secretion, platelets were stained by the indirect method using a murine-produced platelet specific activation-dependent monoclonal antibody, S12, and a goat anti-mouse IgG fluorescein-conjugated antibody. S12 binds to a 140kd alpha granule membrane protein (GMP-140) that is expressed during secretion. Single parameter, 256 channel, log integrated green fluorescence histograms were generated, and negative and positive fluorescent populations were defined. Latamoxef and cefotetan reduced the number of platelets expressing S12 by more than 43%. In contrast, cefoxitin reduced the number of platelets expressing S12 by only 13.5%. The inhibition of GMP-140 expression per platelet was calculated by converting the log data to linear fluorescence intensity. Latamoxef and cefotetan inhibited expression of GMP-140 by 88% and 87% respectively. Free N-MTT inhibited its expression by 68%. In contrast cefoxitin reduced GMP-140 expression per platelet by only 45%.

A randomized trial comparing imipenem/cilastatine alone with latamoxef plus tobramycin in febrile neutropenic patients with lung cancer.

We conducted a randomized trial to compare the efficacy of imipenem/cilastatine (IPM/CS) monotherapy with that of a combination of latamoxef (LMOX) and tobramycin (TOB) in the initial management of fever and neutropenia in patients with lung cancer. Leukocytopenic febrile patients (less than 3,000 leukocytes per microliters; temperature greater than 38 degrees C) with lung cancer given induction therapy were randomly assigned to receive intravenous treatment with either 1 g IPM/CS twice daily or 2 g LMOX plus 90 mg TOB twice daily. A total 101 febrile episodes were studied. Fifty-one episodes were treated with IPM/CS and 50 with LMOX+TOB. Fifty-nine of the febrile episodes were bacteriologically confirmed, while an organism could not be isolated despite the presence of obvious clinical infection in the remaining 42. The response rate was 82% with IPM/CS and 80% with combination therapy. This difference was not statistically significant. The response rate regarding gram-negative infections was 10 out of 14 (71%) in the IPM/CS group and seven out of 12 (58%) in the LMOX+TOB group. This difference was also not significant (P = 0.484). The response rate in severely neutropenic patients (neutrophils less than 100/microliters) was low (P = 0.078). Three patients in the IPM/CS group were withdrawn from the study due to skin rash and vomiting. Therapy with IPM/CS monotherapy was as effective as a combination regimen.

[Acquired coagulopathy caused by administration of parenteral broad-spectrum antibiotics].

Between October 1988 and May 1989, four cancer patients treated by broad-spectrum antibiotics developed a hemorrhagic diathesis induced by vitamin k (VK) deficiency. Activated partial thromboplastin time (APTT), prothrombin time (PT), factor II (FII) and protein induced by vitamin k absence of antagonist-II (PIVKA-II) were measured after administration of antibiotics and VK in all 4 patients. All these patients had been receiving intravenous hyperalimentation (IVH) and antibiotics for various infections. But all or them developed hemorrhagic diathesis within five days after the initiation of broad-spectrum cephem antibiotics (LMOX or CMNX). The abnormalities were 1) marked decrease of F II (6-18%), 2) prolongation of APTT (58.4-200 seconds), 3) prolongation of PT (7-21%), 4) marked increase of PIVKA-II (17-80 less than AU/ml). After being treated by intravenous administration of VK, hemorrhagic diathesis and abnormalities of coagulation tests except for PIVKA-II were corrected quickly in three evaluated patients. The measurement of PIVKA-II seemed to be useful to diagnose the hemorrhagic diathesis caused by VK deficiency in the patients during administration of antibiotics.

Single dose prophylaxis in colorectal surgery.

Moxalactam disodium (Latamoxef), was evaluated as a single dose prophylactic antibiotic against wound infection in open colorectal surgery. One hundred and five consecutive patients admitted to the university department of surgery, Wellington Hospital, were studied. Twelve patients were excluded because either the antibiotic was not given or antibiotics were given for other reasons. Eleven patients developed early wound infections and one further patient developed a late infection, an overall wound infection rate of 13% (95% CI 7-19). Whilst this infection rate is higher than that previously reported from this unit using more prolonged (3 dose) antibiotic prophylaxis (9.8%, 95% CI 9.6-10) the difference is not likely to be significant because the patient groups were not matched, and the comparisons were sequential. On the basis of the present study it is concluded that 1 g of moxalactam disodium administered at the induction of anaesthesia in open colorectal surgery is inexpensive, is associated with a low incidence of side effects and its further use in colorectal surgery would seem to be justified.

Inhibition of platelet aggregation by moxalactam and free N-methylthiotetrazole.

The effects of moxalactam and free N-methylthiotetrazole (N-MTT) in vitro on platelet aggregation induced by adenosine diphosphate (ADP), arachidonic acid, collagen, epinephrine, or ristocetin were determined. Moxalactam at concentrations of 1.9 mM and 5.7 mM inhibited platelet aggregation induced by ADP, arachidonic acid, epinephrine, and ristocetin. Although the aggregatory activity of collagen was not inhibited with 1.9 mM moxalactam, an increase in the concentration of moxalactam to 5.7 mM significantly inhibited collagen-induced platelet aggregation. Inhibition of platelet aggregation by free N-MTT was also concentration dependent. The lowest concentration of N-MTT used in this study, 5.7 mM, inhibited platelet aggregation induced by both arachidonic acid and ristocetin. At a concentration of 28 mM, N-MTT inhibited aggregation induced by ADP, collagen, epinephrine, and ristocetin, but not by arachidonic acid. At 57 mM N-MTT, almost complete inhibition of platelet aggregation occurred for all five agonists tested.

[Postoperative changes in amount of granulocyte-elastase, alpha 1-antitrypsin and other acute phase reactants in blood in obstetrical and gynecological patients].

Postoperative changes in acute phase reactants (APR) upon administration of latamoxef (LMOX) were studied in 43 patients who underwent laparotomy (total hysterectomy, cesarean section or resection of ovarian tumor). The results obtained are summarized as follows. 1. Postoperative changes in APR, i.e., amount of granulocyte-elastase, alpha 1-antitrypsin (alpha 1-AT), alpha 1-acid glycoprotein, haptoglobin and CRP, in the maternal blood were determined. These 5 markers increased and tended to decrease at 7 days and 14 days after surgery, respectively, in the total hysterectomy group. The vital defense response to surgical invasion and the reaction occurring during the process of recovery show that changes in level of granulocyte-elastase, alpha 1-AT and CRP immediately reflect the resulting inflammatory reaction. The changes in elastase and alpha 1-AT levels upon cesarean section showed a similar tendency, but levels of these markers were high as a whole during pregnancy and postpartum. 2. There were no postoperative complications or subjective or objective side effects of the LMOX treatment in any of the studied patients, suggesting that LMOX is useful for the prevention of postoperative infection.