Knock-down of USP22 by small interfering RNA interference inhibits HepG2 cell proliferation and induces cell cycle arrest

The Ubiquitin--specific protease 22 (USP22) is a new putative cancer stem cell marker, which plays a significant role in tumorigenesis and cell--cycle progression. However, little is known about the impact of USP22 knock--down on the growth of human hepatoma cell lines. In this study, elevated expression of USP22 was observed in the human HepG2 hepatic cancer cell line compared to the normal human hepatocyte Chang liver cell line. Subsequently, we used siRNA specifically suppressing expression of USP22 and observed that the knock--down of USP22 could effectively induce cell cycle arrest and inhibit HepG2 cell proliferation. Furthermore, our results showed that USP22 deletion caused down--regulation of cyclin D2 expression and up--regulation of p15 and p21 expression. Collectively, Our findings indicate that USP22 may be responsible for HepG2 cell growth and USP22 regulates the cell cycle via the c--Myc/cyclin D2 pathway and down--regulating p15 and p21 expression in HepG2 cell.

pH and temperature dual-sensitive liposome gel based on novel cleavable mPEG-Hz-CHEMS polymeric vaginal delivery system

Background

In this study, a pH and temperature dual-sensitive liposome gel based on a novel cleavable hydrazone-based pH-sensitive methoxy polyethylene glycol 2000-hydrazone-cholesteryl hemisuccinate (mPEG-Hz-CHEMS) polymer was used for vaginal administration.

Methods

The pH-sensitive, cleavable mPEG-Hz-CHEMS was designed as a modified pH-sensitive liposome that would selectively degrade under locally acidic vaginal conditions. The novel pH-sensitive liposome was engineered to form a thermogel at body temperature and to degrade in an acidic environment.

Results

A dual-sensitive liposome gel with a high encapsulation efficiency of arctigenin was formed and improved the solubility of arctigenin characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry. The dual-sensitive liposome gel with a sol-gel transition at body temperature was degraded in a pH-dependent manner, and was stable for a long period of time at neutral and basic pH, but cleavable under acidic conditions (pH 5.0). Arctigenin encapsulated in a dual-sensitive liposome gel was more stable and less toxic than arctigenin loaded into pH-sensitive liposomes. In vitro drug release results indicated that dual-sensitive liposome gels showed constant release of arctigenin over 3 days, but showed sustained release of arctigenin in buffers at pH 7.4 and pH 9.0.

Conclusion

This research has shed some light on a pH and temperature dual-sensitive liposome gel using a cleavable mPEG-Hz-CHEMS polymer for vaginal delivery.

Effects of a novel pH-sensitive liposome with cleavable esterase-catalyzed and pH-responsive double smart mPEG lipid derivative on ABC phenomenon

BACKGROUND

The ABC phenomenon is described as a syndrome of accelerated clearance of polyethylene glycol (PEG)-modified liposomes from the bloodstream when repeatedly injected, with their increased accumulation in the liver and spleen.

METHODS

To clarify this immune response phenomenon, we evaluated a novel modified pH-sensitive liposome with a cleavable double smart PEG-lipid derivative (mPEG-Hz-CHEMS).

RESULTS

The ABC phenomenon in mice was brought about by repeated injection of conventional PEG-PE liposomes and was accompanied by a greatly increased uptake in the liver. However, a slight ABC phenomenon was brought about by repeated injection of mPEG-CHEMS liposomes and was accompanied by only a slightly increased uptake in the liver, and repeated injection of mPEG-Hz-CHEMS liposomes did not induce the ABC phenomenon and there was no increase in liver accumulation. This finding indicates that the cleavable mPEG-Hz-CHEMS derivative could lessen or eliminate the ABC phenomenon induced by repeated injection of PEGylated liposomes.

CONCLUSION

This research has shed some light on a solution to the ABC phenomenon using a cleavable PEG-Hz-CHEMS derivative encapsulated in nanoparticles.

Effects of poly(amidoamine) dendrimers on ocular absorption of puerarin using microdialysis

PURPOSE

The purpose of this study was to investigate the effects of poly(amidoamine) (PAMAM) dendrimers on ocular absorption of puerarin.

METHODS

The samples of rabbits' aqueous humor were collected by in vivo microdialysis. The ocular pharmacokinetic properties of puerarin were measured to evaluate the effects of PAMAM dendrimers on ocular absorption of puerarin.

RESULTS

In the pharmacokinetic studies, the AUC(0∼∞) values of puerarin solution with 0.2% (w/v) PAMAM dendrimers (G3.0, G4.0, G5.0) were greater than those in the control group by 2.3-, 3.5-, and 2.1-folds, respectively. The C(max) values of puerarin solution with 0.2% (w/v) PAMAM dendrimers were 1.5, 2.5, and 1.3 times the values of the control group and the t(1/2) values were significantly longer than that of control group.

CONCLUSIONS

Using PAMAM dendrimers might be a promising strategy to enhance the absorption of puerarin. The generation of PAMAM dendrimers may play a key role in increasing the ocular absorption of puerarin.

[Ocular pharmacokinetics of puerarin in anesthetic rabbits by microdialysis]

OBJECTIVE

To establish the model of microdialysis, and study the ocular pharmacokinetics of puerarin in anesthetic rabbits.

METHOD

Implanted the probe into anterior chamber of anesthetic rabbit by surgery. After balanced for 2 h, 1% puerarin eye drop (100 microL) was applied into the cul-de-sac with micropipette. Immediately the dialysate was collected at different time and detected by HPLC with the detection wavelength of 249 nm. The mobile phase was methanol and 0.1% citric acid solution (30:70); the flow rate was 1.0 mL x min(-1).

RESULT

After the administration, puerarin can be absorbed into aqueous humor quickly. The peak concentration of puerarin appeared at about 1 h and then reduced gradually. The peak concentration(C(max)) is (2.52 +/- 0.31) mg x L(-1). The other lower peak was shown at 3.5 h during the eliminate phase. This might be attributed to the inhibition of aqueous humor production by the puerarin and resulted in a high drug concentration. The area under concentration-time curve (AUC(0-t)) is (5.04 +/- 0.21) mg x h x L(-1) and the eliminate half life (t1/2) is (0.38 +/- 0.13) h.

CONCLUSION

The microdialysis technique can be used to detect the ocular pharmacokinetics of puerarin, and support the valuable pharmacokinetics parameter for the clinical applications of puerarin eye drop.

Impact of JAK2V617F mutation on thrombosis and myeloid transformation in essential thrombocythemia: a multivariate analysis by Cox regression in 141 patients

OBJECTIVE

To perform a multivariate analysis by Cox proportional hazard model of the impact of JAK2 V617F mutation on thrombosis and myeloid transformations in patients with essential thrombocythemia (ET).

PATIENTS AND METHODS

The clinicopathologic features and outcome of a cohort of Chinese ET patients were retrospectively reviewed. JAK2 V617F mutation was detected by allele-specific polymerase chain reaction. Potential risk factors including JAK2 V617F that might impact on thrombosis and outcome were studied by multivariate analysis with Cox proportional hazard model.

RESULTS

Of 141 patients studied, JAK2 V617F was found in 80 cases (57%). JAK2 V617F was positively correlated with hemoglobin and leukocyte count at diagnosis. Univariate analysis showed significant thrombotic risks to be JAK2 V617F (P=0.006), hemoglobin >13 g/dl (P=0.015), and age >55 years (P=0.011). However, in multivariate analysis, only age and hemoglobin were independent risk factors. JAK2 V617F was unrelated to survival or leukemic/myelofibrotic transformation.

CONCLUSION

In Chinese patients with ET, JAK2 V617F was positively associated with age, hemoglobin, and leukocyte count, but was not an independent risk for thrombosis.

Methylation of cyclin-dependent kinase inhibitors, XAF1, JUNB, CDH13 and soluble Wnt inhibitors in essential thrombocythaemia

BACKGROUND

Methylation of genes regulating cell-cycle check-point (INK4 cyclin-dependent kinase inhibitors), apoptosis (XAF1), adhesion (CDH13), JUNB and Wnt signalling (soluble Wnt inhibitors) has been implicated in pathogenesis of haematological and epithelial cancers.

METHOD

The authors studied the methylation status of CDKN2A, CDKN2B, XAF1, CDH13, JUNB and a panel of soluble Wnt inhibitors including WIF1, DKK3, APC, SFRP1, SFRP2, SFRP4 and SFRP5 by methylation-specific PCR in 31 bone marrow and 21 peripheral blood samples of patients with essential thrombocythaemia.

RESULTS AND DISCUSSION

There was no evidence of hypermethylation of all these genes in both the BM and PB samples. Therefore, in contrast to myeloid leukaemias, methylation of these genes regulating the cell cycle, apoptosis, adhesion and Wnt signalling does not play an important role in the pathogenesis of myeloproliferative diseases. Whether differential methylation may occur in the progenitor or mature blood cell compartments remains to be verified. Our study contributes to the literature on methylation in chronic myeloproliferatve diseases.

Epigenetic inactivation of the miR-34a in hematological malignancies

miR-34a is a transcriptional target of p53 and implicated in carcinogenesis. We studied the role of miR-34a methylation in a panel of hematological malignancies including acute leukemia [acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL)], chronic leukemia [chronic lymphocytic leukemia (CLL) and chronic myeloid leukemia (CML)], multiple myeloma (MM) and non-Hodgkin's lymphoma (NHL). The methylation status of miR-34a promoter was studied in 12 cell lines and 188 diagnostic samples by methylation-specific polymerase chain reaction. miR-34a promoter was unmethylated in normal controls but methylated in 75% lymphoma and 37% myeloma cell lines. Hypomethylating treatment led to re-expression of pri-miR-34a transcript in lymphoma cells with homozygous miR-34a methylation. In primary samples at diagnosis, miR-34a methylation was detected in 4% CLL, 5.5% MM samples and 18.8% of NHL at diagnosis but none of ALL, AML and CML (P = 0.011). In MM patients with paired samples, miR-34a methylation status remained unchanged at progression. Amongst lymphoid malignancies, miR-34a was preferentially methylated in NHL (P = 0.018), in particular natural killer (NK)/T-cell lymphoma. In conclusion, amongst hematological malignancies, miR-34a methylation is preferentially hypermethylated in NHL, in particular NK/T-cell lymphoma, in a tumor-specific manner, therefore the role of miR-34a in lymphomagenesis warrants further study.

[Corneal penetration of PAMAM dendrimers-coated puerarin liposomes]

OBJECTIVE

To study the corneal penetration of PAMAM dendrimers-coated puerarin liposomes in rabbits.

METHOD

Evaluated PAMAM (G2, G3) dendrimers-coated puerarin liposomes were prepared and the in vitro transcorneal penetration were compared to puerarin drop solution and uncoated liposomes. The effect of different proportion of PAMAM to phospholipids in formulation on corneal penetration and the penetration parameters were investigated.

RESULT

The steady state fluxes and permeability coefficients of puerarin by PAMAM G2 (1.0%) and PAMAM G3 (0.5%) coated puerarin liposomes were greater than that by puerarin drop solution and uncoated liposomess (P < 0.01), meanwhile the PAMAM G2 (1.0%) and PAMAM G3 (0.5%) coated liposomes were better than other ratios of coated liposomes for improvement of corneal penetration (P < 0.01).

CONCLUSION

The PAMAM coated liposomes is able to enhance the corneal penetration of puerarin and promising as an ocular drug carriers.

Detection of the unusual magnetic orders in the pseudogap region of a high-temperature superconducting YBa2Cu3O6.6 crystal by muon-spin relaxation

We present muon-spin relaxation (muSR) measurements on a large YBa2Cu3O6.6 single crystal in which two kinds of unusual magnetic order have been detected in the pseudogap region by neutron scattering. A comparison is made to measurements on smaller, higher quality YBa2Cu3Oy single crystals. One type of magnetic order is observed in all samples, but does not evolve significantly with hole doping. A second type of unusual magnetic order is observed only in the YBa2Cu3O6.6 single crystal. This magnetism has an ordered magnetic moment that is quantitatively consistent with the neutron experiments, but is confined to just a small volume of the sample ( approximately 3%). Our findings do not support theories that ascribe the pseudogap to a state characterized by loop-current order, but instead indicate that dilute impurity phases are the source of the unusual magnetic orders in YBa2Cu3Oy.

HLA associations, microsatellite instability and epigenetic changes in thyroid lymphoma in Chinese

In Chinese, autoimmune thyroid disease (AITD) is very common but lymphoma of the thyroid is a rare disease. Southern Chinese AITD is common in females and is strongly linked to the HLA haplotype A2B46DR9. We studied the HLA association, aberration p15, p16 and p73 promoter methylation and microsatellite instability in Chinese primary thyroid lymphoma patients to elucidate their relationship with AITD and the relationship between thyroid diffuse large cell lymphoma (DLCL) and marginal zone lymphomas (MZL). Despite a female preponderance (8:1) and the finding of cases with histological and immunological evidence of AITD, a significant HLA association was not found. MSI was absent, but aberrant promoter methylation was found in both thyroid MZL and DLCL and p73 methylation was unexpectedly common.

Tumor necrosis factor alpha promoter polymorphism and the risk of chronic lymphocytic leukemia and myeloma in the Chinese population

The -308 GA promoter polymorphism of tumor necrosis factor alpha (TNFalpha) has been reported to be associated with an increased risk of lymphoid malignancies in Caucasians. We studied the incidence and prognostic significance of this polymorphism in Chinese patients with plasma cell myeloma (PCM), chronic lymphocytic leukemia (CLL) and lymphomas. Despite a far lower incidence of PCM and CLL in the Chinese population compared with Caucasians, the rates of TNFalpha-308A were similar to those in Caucasians, both in the study and control populations. Similarly, there was no increased rate of TNFalpha-308A in all the lymphomas studied, irrespective of lineage. However, TNFalpha-308A is significantly associated with female CLL cases and confers a strong negative prognostic impact for Chinese CLL. These argue for a possible biological role for increased TNFalpha production in CLL progression in low-risk individuals.

[Rosiglitazone and all-trans retinoic acid inhibit human myeloma cell proliferation via apoptosis signaling pathway modulation]

OBJECTIVE

To investigate the effects of artificial ligand of peroxisome proliferators activated receptors (PPARs), rosiglitazone (RGZ) and all trans-retinoic acid (ATRA) on human myeloma cell line growth in vitro and in vivo.

METHODS

U266 and RPMI 8226 cells were treated with different concentration of RGZ in the presence or absence of ATRA and the results were studied by 3H-TdR thymidine incorporation (for cells proliferation), Annexin V-PI staining and caspase-3 activity assay (for cells apoptosis), RT-PCR (for FLIP, XIAP and survivin mRNA expression), and tumor formation test in BALB/c nude mice.

RESULTS

Exposure to RGZ induced proliferation inhibition in a dose-dependent manner in both U266 (r = 0.991, P < 0.01) and RPMI 8226 cells (r = 0.961, P < 0.01). A combination of RGZ with ATRA could enhance the inhibition effect (P < 0.001 in U266, P < 0.01 in RPMI8226). 10 micromol/L of RGZ induced apoptosis of (9.8 +/- 1.7)% in U266 cells and (10.7 +/- 3.3)% in RPMI8226 cells, in a time and dose dependent manner and combined with ATRA intensified the apoptosis induction effects (P < 0.01 in both cell lines). The FLIP, XIAP and survivin mRNAs were expressed in both cell lines and their levels decreased significantly after cultured with RGZ. The addition of RGZ + ATRA in the culture further decreased the levels. Caspase-3 activity increased substantially with the increase of RGZ concentration and the addition of RGZ + ATRA in the culture medium showed similar synergism effect on caspase-3 activation (P < 0.01). The xenograft of U266 cells in BALB/c nude mice were inhibited by RGZ and so did more by the combination of RGZ and ATRA (P < 0.01).

CONCLUSION

The down-regulation of FLIP, XIAP and Survivin induced by RGZ can activate caspase-3, whereby induced apoptosis and proliferation inhibition in myeloma cells. ATRA can enhance these effects of RGZ.

Organ-specific hemosiderosis and functional correlation in Chinese patients with thalassemia intermedia and hemoglobin H disease

We performed MRI assessment in 37 adult Chinese patients with thalassemia intermedia and hemoglobin H disease. Despite abnormal ferritin and liver T2*, only 5% of patients had cardiac hemosiderosis. The two patients with reduced ejection fraction had normal cardiac T2*. Half of the cases showed pituitary and pancreatic iron loading. Subclinical endocrine abnormalities (HOMA, insulin growth factor) showed correlation with pancreatic, pituitary, and cardiac MRI values. Prospective data with serial functional and imaging monitoring is needed to verify the utility for chelation to improve cardiac and endocrine function in this group of patients.

Inhomogeneous magnetic-field response of YBa2Cu3Oy and La2-xSrxCuO4 persisting above the bulk superconducting transition temperature

We report that in YBa2Cu3Oy and La2-xSrxCuO4 there is a spatially inhomogeneous response to the magnetic field for temperatures T extending well above the bulk-superconducting transition temperature Tc. An inhomogeneous magnetic response is observed above Tc even in ortho-II YBa2Cu3O6.50, which has highly ordered doping. The degree of the field inhomogeneity above Tc tracks the hole-doping dependences of both Tc and the density of the superconducting carriers below Tc, and therefore is apparently coupled to superconductivity.

Epigenetic dysregulation of the Wnt signalling pathway in chronic lymphocytic leukaemia

Background:

Wnt signalling has recently been implicated in the pathogenesis of cancer.

Methods:

This study investigated the activity of Wnt signalling in peripheral blood chronic lymphocytic leukaemia (CLL) lymphocytes, and the methylation status of seven soluble Wnt antagonist genes, including WIF1, DKK3, APC, SFRP1, SFRP2, SFRP4 and SFRP5, by using methylation-specific PCR in the peripheral blood CLL lymphocytes and bone marrow samples of patients with CLL at diagnosis.

Results:

In the peripheral blood CLL lymphocytes, constitutive activation of Wnt signalling was detected, associated with hypermethylation of the soluble Wnt inhibitor genes. In the diagnostic CLL marrow samples, methylation of the seven genes was detected in up to 36.4% of samples. Moreover, 23 (52.3%) patients had methylation of at least one of the seven genes, of whom 14 (60.8%) had methylation of two or more Wnt inhibitor genes. Apart from an association of advanced age with DKK3 methylation, there was no association of gene hypermethylation with either clinical characteristics (including age, gender, lymphocyte count at diagnosis, Rai stage and poor-risk karyotype) or survival.

Conclusion:

Wnt signalling is constitutively activated in CLL B lymphocytes in association with methylation of multiple soluble Wnt antagonist genes. Methylation of these soluble Wnt antagonist genes, occasionally multiple genes, in primary CLL marrow samples suggests an important role in CLL pathogenesis. Moreover, this study underscored the importance of studying methylation of a panel of, but not individual, genes regulating a cellular pathway.

Review article: current management of metastatic colorectal cancer - the evolving impact of targeted drug therapies

BACKGROUND

The field of colorectal cancer chemotherapy has been transformed by the advent of molecule-specific drugs. Combined use of such drugs enhances tumour response rates, but controlled data quantifying the relative efficacy and cost-effectiveness of different drug combinations on overall survival remain scarce.

AIM

To conduct an overview of published clinical trials in advanced colorectal cancer, with the objective of framing provisional approaches to current management.

METHODS

An NCBI/PubMed search was performed using the strings, 'colorectal cancer' ('metastatic' or 'advanced' or 'palliative') and ('chemotherapy' or 'drug therapy' or 'targeted' or 'target-specific' or 'molecularly-targeted').

RESULTS

Combinations of target-specific drugs (with or without the DNA-alkylating agent oxaliplatin) have substantially enhanced colorectal cancer time to progression over the last decade and have also expedited surgical resection of liver metastases. Disease-free survival, overall survival and quality of life are favourably influenced.

CONCLUSIONS

Target-specific drugs improve palliative efficacy in the setting of advanced colorectal cancer. However, key issues persist as to the cost-effectiveness of these newer drug treatments, and further controlled trials are needed to resolve this important debate.