Inhibitory interactions of the 2,3-dihydro-6,7-dihydroxy-1H-isoindol-1-one scaffold with Bunyavirales cap-snatching endonucleases expose relevant drug design features

The World Health Organization (WHO) identifies several bunyaviruses as significant threats to global public health security. Developing effective therapies against these viruses is crucial to combat future outbreaks and mitigate their impact on patient outcomes. Here, we report the synthesis of some isoindol-1-one derivatives and explore their inhibitory properties over an indispensable metal-dependent cap-snatching endonuclease (Cap-ENDO) shared among evolutionary divergent bunyaviruses. The compounds suppressed RNA hydrolysis by Cap-ENDOs, with IC50 values predominantly in the lower μM range. Molecular docking studies revealed the interactions with metal ions to be essential for the 2,3-dihydro-6,7-dihydroxy-1H-isoindol-1-one scaffold activity. Calorimetric analysis uncovered Mn2+ ions to have the highest affinity for sites within the targets, irrespective of aminoacidic variations influencing metal cofactor preferences. Interestingly, spectrophotometric findings unveiled sole dinuclear species formation between the scaffold and Mn2+. Moreover, the complexation of two Mn2+ ions within the viral enzymes appears to be favourable, as indicated by the binding of compound 11 to TOSV Cap-ENDO (Kd = 28 ± 3 μM). Additionally, the tendency of compound 11 to stabilize His+ more than His- Cap-ENDOs suggests exploitable differences in their catalytic pockets relevant to improving specificity. Collectively, our results underscore the isoindolinone scaffold's potential as a strategic starting point for the design of pan-antibunyavirus drugs.

Dosimetric and radiobiological comparison of IMRT, VMAT, and helical tomotherapy planning techniques in hippocampal sparing whole brain radiotherapy with simultaneous integrated boost for multiple brain metastases

To compare treatment planning and dosimetric outcomes for hippocampal sparing whole brain radiotherapy (WBRT) with the simultaneous integrated boost (SIB) in brain metastasis (BM) patients using tumour control probability (TCP) and normal tissue complication probability (NTCP) formalism between IMRT, VMAT, and HT techniques. In this retrospective study, the treatment data of 20 BM patients who typically received whole brain radiation with SIB treatment were used. Prescription doses of 30 Gy and 36 Gy was delivered in 10 fractions for WBRT and SIB, respectively. Niemierko and LKB models were applied for calculating TCP and NTCP. All the plans were evaluated for the RTOG 0933 protocol criteria and found acceptable. Additionally, the homogeneity of the PTV boost is 0.07 ± 0.01, 0.1 ± 0.04, and 0.08 ± 0.02 for IMRT, VMAT, and HT, respectively (P < 0.05). The percentage of TCP for the PTV boost was 99.99 ± 0.003, 99.98 ± 0.004, and 99.99 ± 0.002 of IMRT, VMAT, and HT, respectively, (P < 0.005). The NTCP value of the lenses was higher with the VMAT plan as compared to IMRT and HT Plans. The hippocampal NTCP values are equal in all three planning proficiencies. The techniques like IMRT, VMAT, and HT can reduce the dose received by hippocampus to the dosimetric threshold during the delivery of WBRT with hippocampal sparing and can simultaneously boost multiple metastases. Overall, the high-quality dose distribution, TCP, and NTCP comparison between all three planning techniques show that the HT technique has better results when compared to the VMAT and IMRT techniques.

The Life Cycle of Aurelia aurita Depends on the Presence of a Microbiome in Polyps Prior to Onset of Strobilation

Aurelia aurita's intricate life cycle alternates between benthic polyp and pelagic medusa stages. The strobilation process, a critical asexual reproduction mechanism in this jellyfish, is severely compromised in the absence of the natural polyp microbiome, with limited production and release of ephyrae. Yet, the recolonization of sterile polyps with a native polyp microbiome can correct this defect. Here, we investigated the precise timing necessary for recolonization as well as the host-associated molecular processes involved. We deciphered that a natural microbiota had to be present in polyps prior to the onset of strobilation to ensure normal asexual reproduction and a successful polyp-to-medusa transition. Providing the native microbiota to sterile polyps after the onset of strobilation failed to restore the normal strobilation process. The absence of a microbiome was associated with decreased transcription of developmental and strobilation genes as monitored by reverse transcription-quantitative PCR. Transcription of these genes was exclusively observed for native polyps and sterile polyps that were recolonized before the initiation of strobilation. We further propose that direct cell contact between the host and its associated bacteria is required for the normal production of offspring. Overall, our findings indicate that the presence of a native microbiome at the polyp stage prior to the onset of strobilation is essential to ensure a normal polyp-to-medusa transition. IMPORTANCE All multicellular organisms are associated with microorganisms that play fundamental roles in the health and fitness of the host. Notably, the native microbiome of the Cnidarian Aurelia aurita is crucial for the asexual reproduction by strobilation. Sterile polyps display malformed strobilae and a halt of ephyrae release, which is restored by recolonizing sterile polyps with a native microbiota. Despite that, little is known about the microbial impact on the strobilation process's timing and molecular consequences. The present study shows that A. aurita's life cycle depends on the presence of the native microbiome at the polyp stage prior to the onset of strobilation to ensure the polyp-to-medusa transition. Moreover, sterile individuals correlate with reduced transcription levels of developmental and strobilation genes, evidencing the microbiome's impact on strobilation on the molecular level. Transcription of strobilation genes was exclusively detected in native polyps and those recolonized before initiating strobilation, suggesting microbiota-dependent gene regulation.

Anti-tumor activity against multiple myeloma by combination of KW-2478, an Hsp90 inhibitor, with bortezomib

Heat shock protein 90 (Hsp90) is a promising target for anti-tumor therapy. We previously reported the anti-tumor activity of a novel Hsp90 inhibitor, KW-2478, in multiple myeloma (MM) as a single agent. In this study, we examined the combinational effect of KW-2478 and bortezomib, a proteasome inhibitor, in vitro and in vivo. In vitro, KW-2478 enhanced bortezomib-induced cell growth inhibition, both in MM cell lines and primary patient MM cells. The combination of KW-2478 and bortezomib also induced caspase activation in MM cell lines. Interestingly, the combination synergistically enhanced the expression of Hsp70B, a homolog of Hsp70, in human MM cells and peripheral blood mononuclear cells, indicating Hsp70B could be a surrogate biomarker for the combination of Hsp90 and proteasome inhibitors. In vivo, the combination of KW-2478 with bortezomib showed synergistic anti-tumor activity without significant body weight loss in a subcutaneously inoculated human myeloma model. Furthermore, the combination also showed synergistic reduction of tumor burden in bone marrow in an orthotopic myeloma model. Our results strongly suggest that combination of KW-2478 with bortezomib could exhibit enhanced anti-tumor activity against human myeloma.

The activity of methylated and non-methylated selenium species in lymphoma cell lines and primary tumours

BACKGROUND

Diffuse large B-cell lymphoma patients with low serum selenium concentration at presentation have a lower response rate and overall survival than patients with higher serum selenium. The co-administration of selenium with conventional chemotherapy may be useful in these patients.

PATIENTS AND METHODS

We investigated the activity of two selenium species, methylseleninic acid (MSA) and selenodiglutathione (SDG) in a panel of human lymphoma cell lines and in a primary lymphoma culture system.

RESULTS

Both compounds demonstrated cytostatic and cytotoxic activity with EC(50) values in the range 1.0-10.2 microM. Cell death was associated with an increase in the sub-G1 (apoptotic) fraction by flow cytometry and was not preceded by any obvious cell cycle arrest. SDG, but not MSA, resulted in marked increases in intracellular ROS, particularly in CRL2261 and SUD4 cells in which the cytotoxic activity of SDG was partly, or completely, inhibited by n-acetyl cysteine, suggesting a dependence on ROS for activity in some cells. Both MSA and SDG showed a concentration dependent reduction in percentage viability after a 2-day exposure in primary lymphoma cultures, with EC(50) values in the range 39-300 microM and 9-28 microM, respectively.

CONCLUSION

The selenium compounds MSA and SDG induce cell death in lymphoma cell lines and primary lymphoma cultures, which with SDG may be partly attributable to the generation of ROS.

Pharmacokinetically guided phase I trial of topotecan and etoposide phosphate in recurrent ovarian cancer

A pharmacokinetically guided phase I study of topotecan and etoposide phosphate was conducted in recurrent ovarian cancer. The scheduling of the topoisomerase I and II inhibitors was determined using in vitro activity data. All patients had recurrent disease following prior platinum-containing chemotherapy. Patients had a World Health Organisation performance status of 0–2 and adequate bone marrow, renal and hepatic function. Treatment was with topotecan intravenously for 5 days followed immediately by a 5-day intravenous infusion of etoposide phosphate (EP), with pharmacokinetically guided dose adjustment. Plasma etoposide levels were measured on days 2 and 4 of the infusion. A total of 21 patients entered the study. In all, 48% were platinum resistant and 71% had received prior paclitaxel. The main toxicities were haematological, short lived and reversible. A total of 29% of patients experienced grade 4 thrombocytopenia and 66% grade 4 neutropenia after the first cycle. Neutropenia and thrombocytopenia was dose limiting. The maximum-tolerated dose was topotecan 0.85 mg m⁻² day⁻¹ days 1–5 followed immediately by a 5-day infusion of EP at a plasma concentration of 1 μg ml⁻¹. The response rate (RR) was 28% in 18 evaluable patients. There was marked interpatient variability in topoisomerase IIα levels measured from peripheral lymphocytes, with no observed increase following topotecan. This regimen of topotecan followed by EP demonstrated good activity in recurrent ovarian cancer and was noncrossresistant with paclitaxel. Both the toxicity and RR was higher than would be expected from the single agent data, in keeping with synergy of action.

Population pharmacokinetics of oral morphine and its glucuronides in children receiving morphine as immediate-release liquid or sustained-release tablets for cancer pain

OBJECTIVES

(1) To determine the pharmacokinetics of morphine, morphine-6-glucuronide (M6G), and morphine-3-glucuronide (M3G) in children with cancer receiving morphine as immediate-release morphine liquid or sustained-release tablets. (2) To determine differences with age within the group and from adults. (3) To explore relationships between plasma concentration and pain measurements.

STUDY DESIGN

Blood samples were collected and plasma analyzed by high-performance liquid chromatography with electrochemical and fluorescence detection. Population pharmacokinetic parameters were derived with the program P-PHARM.

RESULTS

Forty children with a median age of 11.4 years (range 1.7 to 18.7 years) received a median dose of 1.4 mg/kg/d (range 0.4 to 24.6 mg/kg/d). A median of 4 blood samples per child was collected. Plasma clearance of morphine was 23.1 mL/min per kg body weight. The volume of distribution was 5.2 L/kg. Molar ratios of M3G/morphine, M6G/morphine, and M3G/M6G were 21.1, 4.7, and 4.2, respectively. Children <11 years had significantly higher clearance and larger volume of distribution for morphine and its glucuronides than older children and adults. Regression analysis indicated average plasma morphine concentration equal to dose (mg/kg/d) x 8.6 (95% confidence interval 7.4 to 9.9). Significant pain was present in 30% of the children. Higher pain scores were recorded in children with average morphine concentrations <12 ng/mL (P <.01 MW).

CONCLUSION

Age differences in morphine pharmacokinetics exist within children and compared with adults. The study supports a starting dose of 1.5 to 2. 0 mg/kg/d to provide plasma morphine concentrations >12 ng/mL in children with cancer pain unrelieved by mild to moderate strength analgesia.

A randomised, concentration-controlled, comparison of standard (5-day) vs. prolonged (15-day) infusions of etoposide phosphate in small-cell lung cancer

PURPOSE

This randomised trial was designed to investigate the activity and toxicity of continuous infusion etoposide phosphate (EP), targeting a plasma etoposide concentration of either 3 micrograms/ml for five days (5d) or 1 microgram/ml for 15 days (15d), in previously untreated SCLC patients with extensive disease.

PATIENTS AND METHODS

EP was used as a single agent. Plasma etoposide concentration was monitored on days 2 and 4 in patients receiving 5d EP and on days 2, 5, 8 and 11 in patients receiving 15d EP, with infusion modification to ensure target concentrations were achieved. Treatment was repeated every 21 days for up to six cycles, with a 25% reduction in target concentration in patients with toxicity.

RESULTS

The study has closed early after entry of 29 patients (14 with 5d EP, 15 with 15d EP). Objective responses were seen in seven of 12 (58%, confidence interval (CI): 27%-85%) evaluable patients after 5d EP, and two of 14 (14%, CI: 4%-42%) evaluable patients after 15d EP (P = 0.038). Grade 3 or 4 neutropenia or leucopenia during the first cycle of treatment was observed in six of 12 patients after 5d EP and 0/14 patients after 15d EP (P = 0.004), with median nadir WBC count of 2.6 x 10(9)/1 after 5d and 5.0 x 10(9)/1 after 15d EP (P = 0.017). Only one of 49 cycles of 15d EP was associated with grade 3 or worse haematological toxicity, compared to 14 of 61 cycles of 5d EP.

CONCLUSIONS

Although the number of patients entered into this trial was small, the low activity seen at 1 microgram/ml in the 15d arm suggests that this concentration is below the therapeutic window in this setting. Further concentration-controlled studies with prolonged EP infusions are required.

In vitro testing of calcium channel blockers and cytotoxic chemotherapy in B-cell low-grade non-Hodgkin's lymphoma

The flux of calcium forms an important intracellular messenger system. The bcl-2 oncoprotein is thought to make cells resistant to a variety of insults, including cytotoxic drugs, by the suppression of apoptosis, which appears to involve the repartitioning of intracellular calcium. Three drugs that affect calcium pathways and may influence this repartitioning, i.e. dantrolene, azumolene (a water-soluble dantrolene analogue) and nimodipine, were studied in cell culture, using both a transformed follicle centre lymphoma cell line and primary culture of lymphoma cells in vitro in a manner that resulted in a growth pattern closely resembling that of the malignancy in vivo. Dantrolene and azumolene were potent inducers of cell death in both systems reducing the viable cell count by 70-90% in comparison with normal controls. Nimodipine, in comparison, appeared to have no significant effect. These results obtained in an in vitro setting suggest that further evaluation of dantrolene and azumolene for the treatment of low-grade non-Hodgkin's lymphoma is warranted.

Continuous infusional topotecan in advanced breast and non-small-cell lung cancer: no evidence of increased efficacy

Two open, phase II studies were performed to evaluate the activity and toxicity of infusional topotecan in patients with advanced non-small-cell lung carcinoma (NSCLC) and advanced breast cancer who had not received previous chemotherapy for metastatic disease. Twenty-five patients with an ECOG performance score < 2 were treated with infusional topotecan administered as a daily, continuous intravenous infusion starting at 0.6 mg m(-2) day(-1) (NSCLC) and 0.5 mg m(-2) day(-1) (breast cancer) for 21 days every 4 weeks. Three patients achieved a partial response as defined by WHO criteria: one with NSCLC (8%; 95% CI 0-39%) and two with advanced breast cancer (15%; 95% CI 2-45%). The major toxicities were neutropenia and thrombocytopenia, with one episode of neutropenic sepsis. These data suggest that topotecan delivered as a continuous intravenous infusion over 21 days as single-agent therapy does not appear to offer a clinical advantage over conventional 5-day schedules against advanced NSCLC and advanced breast cancer.

Etoposide pharmacokinetics in a jaundiced infant with letterer-siwe variant of langerhans cell histiocytosis

An infant with hepatocellular jaundice due to Langerhans cell histiocytosis was treated and responded well to intravenous etoposide. Pharmacokinetics demonstrated similar clearance and AUC data in both the jaundiced and non-jaundiced states but myelosuppression was greater when the infant was jaundiced. Children with hepatocellular jaundice require dose reductions of etoposide, despite the similar drag pharmacokinetics to the non-jaundiced state. The mechanisms involved are discussed.

The pharmacokinetics of morphine and morphine glucuronides in kidney failure

The pharmacokinetics of morphine and its glucuronide metabolites were investigated in three groups of patients with kidney failure (nondialyzed, receiving dialysis, and transplantation) and compared with a group of normal healthy volunteers. Patients in all three renal groups were undergoing surgical procedures (nondialyzed group undergoing arteriovenous fistula formation, dialysis group undergoing placement of a peritoneal dialysis catheter, and the transplant group undergoing live donor kidney transplant). A sensitive, specific high-performance liquid chromatographic assay was used to quantitate morphine, morphine-3-glucuronide, and morphine-6-glucuronide. Patients with kidney failure had a significantly increased morphine area under the curve (AUC) compared with control subjects. There was also an increase in the metabolites morphine-3-glucuronide and morphine-6-glucuronide that was severalfold greater than the increase in morphine AUC. This metabolite accumulation was reversed by kidney transplantation, providing an elegant confirmation on the role of the kidney in morphine pharmacology.

A double blind placebo controlled trial of medroxyprogesterone acetate (MPA) in cancer cachexia

Patients with breast cancer treated with MPA often report an improvement in appetite. Similar appetite stimulation is seen in patients treated with some corticosteroids, but MPA has a potential advantage over these drugs in that it does not exert a catabolic effect. MPA (100 mg tds orally) has therefore been compared with placebo in 60 patients with advanced malignant disease. Twenty-one patients in the MPA group and 20 in the placebo group were receiving chemotherapy. Patients were treated for 6 weeks and were assessed at weeks 0, 3 and 6 for appetite, energy, mood and pain using visual analogue scales. Nutritional status was assessed by the measurement of serum proteins and anthropometrics. Karnofsky score was recorded as a measure of performance status. There was a significant improvement in appetite in the MPA group between weeks 0 (pre-study) and 3 (P = 0.0002) and 0 and 6 (P = 0.015). There was no significant improvement in appetite in the placebo group. Supporting this finding was the significant increase in serum thyroid binding pre-albumin and retinol binding protein in the MPA group between weeks 0 and 3 and 0 and 6 (P = 0.023 and P = 0.039 respectively). These two parameters showed no significant change in the placebo group. There was no change in anthropometric measurements, weight, performance status, energy, mood or pain in either group. These data indicate that there was a significant increase in appetite in anorexic patients with advanced cancer treated with MPA which was reflected in increases in rapid turnover proteins reported to reflect nutritional status. However, this apparent increase in appetite did not result in improved weight, performance status, energy levels, mood or relief of pain. Further studies to investigate the effect of higher doses of MPA are indicated.

The analgesic activity of morphine-6-glucuronide

1. The pharmacokinetics, cardio-respiratory effects and analgesic effects of intravenous morphine-6-glucuronide were studied in 20 cancer patients with pain. Four different dose levels (0.5, 1, 2, and 4 mg 70 kg-1) were studied. Plasma concentrations of morphine-6-glucuronide were measured for 12 h after dosing. Pulse rate, respiratory rate and blood pressure were monitored, and pain relief was measured using two rating scales and a visual analogue scale. 2. The mean elimination half-life (+/- s.d.) of morphine-6-glucuronide was 3.2 +/- 1.6 h. The mean AUC standardised to a dose of 1 mg 70 kg-1 was 390 +/- 263 nmol l-1 h. Mean morphine-6-glucuronide clearance was 96 +/- 38 ml min-1. There was a direct relationship between morphine-6-glucuronide plasma clearance and calculated creatinine clearance (r = 0.81, P less than 0.001). 38 +/- 22% of the dose of morphine-6-glucuronide was recovered unchanged in the urine in 24 h. No morphine or morphine-3-glucuronide was detected in the plasma or urine of any patient after morphine-6-glucuronide treatment. 3. Morphine-6-glucuronide exerted a useful analgesic effect in 17/19 assessable patients for periods ranging between 2 and 24 h. No correlation was observed between dose or plasma morphine-6-glucuronide concentrations, and duration or degree of analgesia. No clinically significant changes in cardio-respiratory parameters were observed. No patients reported sedation or euphoria. Nausea and vomiting were notably absent in all cases. 4. Morphine-6-glucuronide is an effective and well-tolerated analgesic. It is likely that the majority of the therapeutic benefit of morphine is mediated by morphine-6-glucuronide.(ABSTRACT TRUNCATED AT 250 WORDS)

A phase I study on the reversal of multidrug resistance (MDR) in vivo: nifedipine plus etoposide

Multidrug resistance (MDR) is one of the mechanisms of resistance to multiple cytotoxic drugs and is mediated by the expression of a membrane pump called the P-glycoprotein. Nifedipine is one of the calcium channel blocking agents which reverses MDR in vitro. Fifteen patients with various malignancies received nifedipine at three dose levels: 40 mg, 60 mg and 80 mg orally twice daily for 6 days. Etoposide was administered intravenously on day 2 in a dose of 150-250 mg m-2 and orally 150-300 mg twice daily on days 3 and 4. Cardiovascular effects of nifedipine were dose limiting and the maximum tolerated dose was 60 mg bid. Mean area under the plasma concentration curve (AUC0-00) and plasma half-life (beta) of nifedipine and its major metabolite MI at the highest dose level were 7.87 microM.h, 7.97 h and 4.97 microM.h, 14.0 h respectively. Nifedipine did not interfere with the pharmacokinetics of etoposide.

Morphine and metabolite behavior after different routes of morphine administration: demonstration of the importance of the active metabolite morphine-6-glucuronide

The pharmacokinetic parameters of morphine, morphine-6-glucuronide, and morphine-3-glucuronide were studied after single-dose morphine administration by five different routes. The quantitative significance of the active metabolite morphine-6-glucuronide was assessed, and the effects of novel dosing forms on morphine metabolism and distribution were examined. After administration of intravenous morphine the morphine-6-glucuronide plasma AUC exceeded that of morphine. After administration of oral morphine very low morphine levels were observed--the morphine-6-glucuronide plasma AUC exceeded that of morphine by a factor of 9:1. Sublingual, buccal, and sustained-release buccal morphine tablet administration resulted in delayed absorption, with attenuation and delay of peak morphine and metabolite levels. Morphine bioavailability and morphine glucuronide production were not altered.