A phase II study of the tolerability and activity of weekly vincristine sulfate liposomes injection (VSLI) in adults with Philadelphia chromosome-negative (Ph-) acute lymphoblastic leukemia (ALL) in second relapse or progressing following two antileukemia treatment lines

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Background: VSLI (Marqibo) is a nanoparticle formulation of vincristine sulfate (VCR) encapsulated in sphingomyelin/cholesterol liposomes called Optisomes. The optisomal formulation lends itself to an improved pharmacokinetic profile and enhanced tumor penetration and concentration. Preclinical studies of VSLI showed enhanced efficacy versus standard VCR in a variety of solid and hematologic malignancies. VSLI has a maximum tolerated dose of 2.25 mg/m2 with no dose cap, while conventional VCR is dosed at 1.4 mg/m2 with a 2 mg dose cap. A previous study in relapsed ALL showed a complete response rate of 19%, warranting further study. Methods: Eligible adult subjects received single agent intravenous VSLI at a dose of 2.25 mg/m2 weekly with no dose cap. This international, multicenter, single-arm study will enroll approximately 56 subjects. Major endpoints include response rate and overall survival (OS). An interim analysis was planned following enrollment of 29 evaluable subjects. Results: 29 heavily pretreated subjects received ≥ 1 dose of VSLI. To date, at least 9 of 29 subjects had clearing of leukemic blasts and achievement of an M1 bone marrow. Based on preliminary data, the median OS is estimated to be 7.5 months (95% CI: 4.7–10.5) using the Kaplan-Meier method. The most frequent related adverse event (AE) was peripheral neuropathy (PN) (48%), half of which was grade 3. No grade 4 PN was reported. Six subjects had 8 treatment-associated grade 4 AEs of neutropenia (4), thrombocytopenia (2), anemia (1), and inappropriate antidiuretic hormone secretion (1). Conclusions: These results are encouraging, as VSLI was given as a single agent to a heavily pretreated patient population who nearly universally received prior VCR. This population typically has a very low response rate to anti-leukemia therapies. Early OS data compares favorably to an historical median OS of ∼ 2 months (8.7 weeks) in a second salvage population (data on file, M. D. Anderson). VSLI was well tolerated in these patients in the context of universal prior vincristine treatment.

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A common variant in MTNR1B, encoding melatonin receptor 1B, is associated with type 2 diabetes and fasting plasma glucose in Han Chinese individuals

AIMS/HYPOTHESIS

Recently, three groups independently reported that variation in MTNR1B, the gene encoding melatonin receptor 1B, was associated with an increased risk of type 2 diabetes, increased fasting plasma glucose and impaired insulin secretion in populations of European ancestry. In the present study, we investigated whether a single MTNR1B polymorphism was associated with type 2 diabetes in Han Chinese individuals, to elucidate whether this is a cross-populational effect.

METHODS

The MTNR1B variant rs10830963 was genotyped in 1,165 type 2 diabetic patients and 1,105 normoglycaemic control individuals of southern Han Chinese ancestry who were residents of the metropolitan area of Shanghai. The risk of developing type 2 diabetes was calculated using a logistic regression model adjusted for age, sex and BMI. A possible association with fasting plasma glucose was analysed in the normoglycaemic control individuals using a multiple linear regression analysis with adjustments for age, sex and BMI.

RESULTS

The genetic variant rs10830963 was associated with an increased risk of type 2 diabetes in our Han Chinese cohort (OR 1.16, 95% CI 1.03-1.31, p = 0.015). As previously described, the risk variant was also associated with increased fasting plasma glucose, showing an increase of 0.068 mmol/l (95% CI 0.036-0.100, p = 4 x 10(-5)) per risk allele.

CONCLUSIONS/INTERPRETATION

A common variant in the MTNR1B gene is associated with an increased risk of type 2 diabetes and increased fasting plasma glucose in Han Chinese, suggesting an important role for this polymorphism in populations of different ethnic and environmental backgrounds.

Construction of a fusion protein between N-terminal 153 peptide of thrombopoietin and erythropoietin

Thrombopoietin (TPO) functions as a regulator of megakaryocytes in their differentiation and maturation, and is a candidate pharmaceutical for the curing of thrombocytopenia. Erythropoietin (EPO) is a hematopoietic cytokine that regulates the level of red blood cell. It is widely used in renal anemia and tumor associated anemia, and is proved to be safe and effective. In order to study the possibility of using TPO-EPO fusion protein for the curing of anemia and thrombocytopenia induced by high dose chemotherapy, a fusion gene is constructed by linking TPO N-terminal 153 peptideand EPO mature peptide-coding region. The fusion gene is expressed in mammalian cells, revealing that the expression product can support the growth of TPO responsive Ba/F3-mpl cells and EPO dependent Bet-2 cells in the absence of any other stimulating cytokine. It also stimulates the formation of erythroid colonies and megakaryocytic colonies in semi-solid bone marrow cultures. These results indicate that the fusion protein has both thein vitro activities of TPO and EPO. The preliminaryin vivo experiment reveals that the TPO-EPO fusion protein containing cell supernatant raises the platelet level by 37 % in mice, while its function on erythroid hematopoiesis remains to be determined. These results indicate that the construction of TPO-EPO fusion protein and the further study of its use in high dose chemotherapy are possible.

The mTOR signaling network: insights from its role during embryonic development

Target of Rapamycin (TOR) signaling, originally discovered as the pathway affected by an antifungal macrolide, exemplifies the potential of medicinal chemistry as a discovery tool. Three decades from its identification, signaling involving the TOR kinase has evolved into a complex network with a crucial role in vertebrate growth control. Specifically, it integrates signals to coordinate cell growth (i.e., enhanced mass and size) and cell cycle progression with sufficiency of nutrients, energy, and growth factors. In this review, we discuss multiple aspects of TOR signaling, including cellular regulators and mediators, human diseases related to TOR dysregulation such as cancer, and signaling nodes in the pathway amenable to targeted drug inhibition. The functions and mechanisms of TOR during embryonic development highlight the dynamic role of TOR signaling and reveal additional functions beyond cell growth control. Embryonic TOR signaling has differential tissue-specific and temporal effects, and is involved in organogenesis, sexual differentiation, and epithelial-to-mesenchymal transition signaling. Molecular mechanisms that may contribute to embryonic-specific TOR functions are also examined here. Finally, this review discusses the complex signaling of mTOR in cancer and the development of mTOR inhibitors for cancer therapy.

Circadian modulation of light-induced locomotion responses in Drosophila melanogaster

The relationship between light and the circadian system has long been a matter of discussion. Many studies have focused on entrainment of light with the internal biological clock. Light also functions as an environmental stimulus that affects the physiology and behaviour of animals directly. In this study, we used light as an unexpected stimulus for flies at different circadian times. We found that wildtype flies showed circadian changes in light-induced locomotion responses. Elevation of locomotor activity by light occurred during the subjective night, and performance in response to light pulses declined to trough during the subjective day. Moreover, arrhythmic mutants lost the rhythm of locomotion responses to light, with promotion of activity by light in timeless(01)mutants and inhibition of activity by light in Clock(ar)mutants. However, neither ablation of central oscillators nor disturbance of the functional clock inside compound eyes was sufficient to disrupt the rhythm of light responses. We show that, compound eyes, which have been identified as the control point for normal masking (promotion of activity by light), are sufficient but not necessary for paradoxical masking (suppression of activity by light) under high light intensity. This, taken together with the clear difference of light responses in wildtype flies, suggests that two different masking mechanisms may underlie the circadian modulation of light-induced locomotion responses.

Auto-antibodies to receptor tyrosine kinases TrkA, TrkB and TrkC in patients with chronic Chagas' disease

The Chagas' disease parasite Trypanosoma cruzi promotes survival and differentiation of neurones by binding and activating nerve growth factor (NGF) receptor TrkA. The functional mimic of NGF in T. cruzi is a surface-bound and shed immunogenic protein [neurotrophic factor/trans-sialidase (TS)], which raised the possibility that immune response to T. cruzi in general and to neurotrophic factor/TS in particular leads to loss of immunological tolerance to host NGF and/or the NGF-binding partner TrkA. In testing this hypothesis, we found that sera of individuals with chronic Chagas' disease bear unique IgG2 autoantibodies that bind TrkA and TrkA family members TrkB and TrkC (ATA). Binding of ATA to Trk receptors is specific because the autoantibodies did not cross-react with five other growth factor receptors, NGF and other neurotrophins, and T. cruzi. Thus, individuals with chronic Chagas' disease produce unique antibodies that react with pan-Trk receptors, one of which (TrkA) T. cruzi exploits to inhibit host cell apoptosis and to promote cellular invasion.

Diagnostic potential of serum protein pattern in Type 2 diabetic nephropathy

AIMS

Microalbuminuria is the earliest clinical sign of diabetic nephropathy (DN). However, the multifactorial nature of DN supports the application of combined markers as a diagnostic tool. Thus, another screening approach, such as protein profiling, is required for accurate diagnosis. Surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) is a novel method for biomarker discovery. We aimed to use SELDI and bioinformatics to define and validate a DN-specific protein pattern in serum.

METHODS

SELDI was used to obtain protein or polypeptide patterns from serum samples of 65 patients with DN and 65 non-DN subjects. From signatures of protein/polypeptide mass, a decision tree model was established for diagnosing the presence of DN. We estimated the proportion of correct classifications from the model by applying it to a masked group of 22 patients with DN and 28 non-DN subjects. The weak cationic exchange (CM10) ProteinChip arrays were performed on a ProteinChip PBS IIC reader.

RESULTS

The intensities of 22 detected peaks appeared up-regulated, whereas 24 peaks were down-regulated more than twofold (P < 0.01) in the DN group compared with the non-DN groups. The algorithm identified a diagnostic DN pattern of six protein/polypeptide masses. On masked assessment, prediction models based on these protein/polypeptides achieved a sensitivity of 90.9% and specificity of 89.3%.

CONCLUSION

These observations suggest that DN patients have a unique cluster of molecular components in serum, which are present in their SELDI profile. Identification and characterization of these molecular components will help in the understanding of the pathogenesis of DN. The serum protein signature, combined with a tree analysis pattern, may provide a novel clinical diagnostic approach for DN.

Performance and comparison of the Cockcroft-Gault and simplified Modification of Diet in Renal Disease formulae in estimating glomerular filtration rate in a Chinese Type 2 diabetic population

AIMS

Our aim was to assess performances of the Cockcroft-Gault and simplified Modification of Diet in Renal Disease (MDRD) formulae in estimating glomerular filtration rate (GFR) in Chinese diabetic populations and their association with vascular risks.

METHODS

A total of 1009 patients with Type 2 diabetes were categorized into low estimated GFR groups (GFR < 60 ml/min/1.73 m(2)) and control groups by the two equations. The performances of these formulae were assessed at different stages of kidney function. Carotid artery intima-media thickness (IMT) and the prevalence of diabetic retinopathy or albuminuria were compared among the groups. The ability of these formulae to identify established vascular risk markers using sensitivity, specificity, positive and negative predictive values were also compared.

RESULTS

The prevalence of low estimated GFR was 32.7% with the Cockcroft-Gault formula and 5.2% with the MDRD formula, respectively. In low estimated GFR subjects by the MDRD formula, IMT was significantly thicker than those by the Cockcroft-Gault formula (1.2 mm vs. 1.0 mm; P < 0.05), with a higher prevalence of albuminuria (78.4 vs. 52.8%, P < 0.05) and diabetic retinopathy (46.5 vs. 30.5%; P < 0.05). The Cockcroft-Gault formula gave a specificity of 71.7% and a sensitivity of 37.0%, and the MDRD formula gave a specificity of 96.6% and a sensitivity of 7.9% in estimating low GFR relevant for established vascular risks.

CONCLUSIONS

These formulae performed differently in Chinese diabetic populations. The simplified MDRD formula is minimally superior to the Cockcroft-Gault formula for its high specificity and positive predictive values in estimating low GFR relevant for vascular risks.

Fabrication and evaluation of calcium phosphate cement scaffold with controlled internal channel architecture and complex shape

The ability to have precise control over internal channel architecture, porosity, and external shape is essential for tissue engineering. The feasibility of using indirect stereo-lithography (SL) to produce scaffolds from calcium phosphate cement materials for bone tissue engineering has been investigated. The internal channel architecture of the scaffolds was created by removal of the negative resin moulds made with SL. Scanning electron microscopy (SEM) showed highly open, well-interconnected channel architecture. The X-ray diffraction examination revealed that the hydroxyapatite phase formed at room temperature in the cement was basically stable up to 850 °C. There was no phase decomposition of hydroxyapatite, although the crystallinity and grain size were different. The ability of resulting structure to support osteoblastic cells culture was tested in vitro. Cells were evenly distributed on exterior surfaces and grew into the internal channels of scaffolds. To exploit the ability of this technique, anatomically shaped femoral supracondylar scaffolds with 300-800 μm interconnected channels were produced and characterized.

T-cell death and cancer immune tolerance

Cancer patients mount adaptive immune responses against their tumors. However, tumor develops many mechanisms to evade effective immunosurveillance. T-cell death caused by tumor plays a critical role in establishing tumor immunotolerance. Chronic stimulation of T cells by tumors leads to activation-induced cell death. Abortive stimulation of T cells by tolerogenic antigen-presenting cells loaded with tumor antigens leads to autonomous death of tumor-specific T cells. Therapeutic approaches that prevent T-cell death in the tumor microenvironment and tumor draining lymph nodes, therefore, should boost adaptive immune responses against cancer.