Her-2 directed systemic delivery of fatty acid synthase (FASN) siRNA with novel liposomal carrier systems in the breast cancer mouse model

Despite the current advancements in the gene silencing therapy in vitro, the systemic delivery of siRNA still remains a challenging task for its transition into clinics. We have previously developed the Her2-targeted fatty acid synthase (FASN) siRNA-encapsulating immunoliposomes (ILs) with a great stability in the presence of serum. We report here the therapeutic potential of the lipid-based novel formulations in the breast cancer mouse model. The growth inhibitory and gene silencing effects of various formulations were determined by measuring the size of the tumor, cell proliferation, apoptotic index and immunoassays against Her2-over expressed tumor xenografts in nude mice. The pegylated DSPC/Chol and DOPE/CHEMS immunoliposomes containing FASN-siRNA significantly decreased the tumor growth relative to non-targeted liposomes. They induced the 1.5-fold increase in cellular apoptosis and several fold decrease in proliferation as compared to non-targeted liposomal formulations of FASN-siRNA. Moreover, FASN-siRNA-ILs produced several fold increase in the ratios of p53/p21 and Bax/Bcl-2. The gene silencing effects of targeted FASN-liposomes were found significantly superior, resulting in 30%-40% downregulation in FASN as compared to non-targeted similar formulations. Both types of FASN immunoliposomes provided a highly efficient approach for targeted delivery in Her-2-expressed breast cancer and thus offered a promising anticancer strategy in the clinical therapy.

Fatty Acid Synthase (FASN) siRNA-Encapsulated-Her-2 Targeted Fab'-Immunoliposomes for Gene Silencing in Breast Cancer Cells

Purpose

The overexpression of Her-2 in 25–30% breast cancer cases and the crosstalk between Her-2 and fatty acid synthase (FASN) establishes Her-2 as a promising target for site-directed delivery. The present study aimed to develop the novel lipid base formulations to target and inhibit the cellular proliferation of Her-2-expressing breast cancer cells through the silencing of FASN. In order to achieve this goal, we prepared DSPC/Chol and DOPE/CHEMS immunoliposomes, conjugated with the anti-Her-2 fab’ and encapsulated FASN siRNA against breast cancer cells.

Methods

We evaluated the size, stability, cellular uptake and internalization of various formulations of liposomes. The antiproliferative gene silencing potential was investigated by the cell cytotoxicity, crystal violet, wound healing and Western blot analyses in Her-2⁺ and Her-2^¯ breast cancer cells.

Results

The data revealed that both nanosized FASN-siRNA-encapsulated liposomes showed significantly higher cellular uptake and internalization with enhanced stability. The cell viability of Her-2⁺ SK-BR3 cells treated with the targeted formulation of DSPC/Chol- and DOPE/CHEMS-encapsulating FASN-siRNA reduced to 30% and 20%, respectively, whereas it was found to be 45% and 36% in MCF-7 cells. The wounds were not only failed to close but they became broader in Her-2⁺ cells treated with targeted liposomes of siRNA. Consequently, the amount of FASN decreased by 80% in SK-BR3 cells treated with non-targeted liposomes and it was 30% and 60% in the MCF-7 cells treated with DSPC/Chol and DOPE/CHEMS liposomes, respectively.

Conclusion

In this study, we developed the formulation that targeted Her-2 for the suppression of FASN and, therefore, inhibited the proliferation of breast cancer cells.

Molecular characterization and susceptibility screening for methicillin-resistant Staphylococcus aureus reveals the dominant clones in a tertiary care hospital in Al Qassim, Saudi Arabia

OBJECTIVE

Staphylococcus aureus has become an important pathogen in hospitals worldwide. Despite its differentiation into human and animal lineages, common methods are used for genotyping. While these methods are useful, they are based on the stable genome, and hence, are insensitive to host-specific subtyping. The objectives of this study were to investigate the repeat-domain of the Clumping-Factor A gene (clfA- R) as an objective and adaptation-sensitive approach.

METHODOLOGY

We have used 113 isolates for susceptibility testing and genotyping by polymerase chain reaction amplification of the clfA- R regions. Of these, 105 were from King Fahad Specialist Hospital, Buraidah and eight were published sequences used as references. Isolates were further confirmed as S. aureus by the commercial Kits. Amplicon sizes were measured and the number of the 18-bp-repeating-units in each isolate was determined against that of methicillin-resistant S. aureus COL (MRSA) sequence.

RESULTS

Results showed that all 42 nasal screening isolates (100%) and all but six isolates from clinical specimens were MRSA with 37% of the former and 50% of the latter isolates showing community-acquired-MRSA susceptibility patterns. clfA-R analysis grouped 113 isolates into 14 repeat-genotypes. The two dominant types, D and X, represented the long- and short clfA-R types found in humans and animals, respectively. Linezolid, rifampicin, and vancomycin were the drugs of choice.

CONCLUSIONS

clfA-R was useful in rapid genotyping and implied host-specific phenotypic properties of the ClfA. It has been recommended that the approach used in regional laboratories for uniform strain-profiling. Future work will show more insights into the gene content and origins of clones .

The Possible Role of Helicobacter pylori in Gastric Cancer and Its Management

Helicobacter pylori (HP) is a facultative anaerobic bacterium. HP is a normal flora having immuno-modulating properties. This bacterium is an example of a microorganism inducing gastric cancer. Its carcinogenicity depends on bacteria-host related factors. The proper understanding of the biology of HP inducing gastric cancer offers the potential strategy in the managing of HP rather than eradicating it. In this article, we try to summarize the biology of HP-induced gastric cancer and discuss the current pharmacological approach to treat and prevent its carcinogenicity.

Liposomal formulation of glycosphingolipids from Sphingomonas paucimobilis induces antitumour immunity in mice

Natural Killer T (NKT) cells play an important role in host's anti-tumour immune response. Glycosphingolipids (GSLs) isolated from Sphingomonas paucimobilis have the ability to stimulate NKT cells. In this study, the activity of free GSLs or GSLs-incorporated liposomes (glycosphingosomes) was investigated against dimethyl-α-benzanthracene (DMBA)-induced tumours in mice. The anti-tumour immunity of GSLs- or glycosphingosomes-loaded bone marrow-derived dendritic cells (BMDCs) was investigated in tumour-bearing mice. The Immunotherapeutic potential of co-administration of liposomal doxorubicin (Lip-Dox) and GSLs or glycosphingosomes was assessed by measuring cytokine levels and VEGF in the tumour tissues. Pretreatment with glycosphingosomes significantly delayed the frequency of tumour formation. Immunotherapy with glycosphingosomes-loaded BMDCs increased serum IFN-γ level and survival rate in mice. The effect of immunotherapy was dependent on effector functions of NK cells because the depletion of NK cells abolished the effects of immunotherapy. There was reduced tumour growth with low expression of VEGF in the group of mice treated with glycosphingosomes and Lip-Dox combination. Moreover, the splenocytes secreted higher levels of IFN-γ, IL-12 and lower TGF-β level. The results of this study indicate that glycosphingosomes can induce better antitumour immunity and may be considered a novel formulation in antitumour therapy.

Combination of glycosphingosomes and liposomal doxorubicin shows increased activity against dimethyl-α-benzanthracene-induced fibrosarcoma in mice

The present study aimed to assess the antitumor effect of glycosphingolipid-incorporated liposomes (glycosphingosomes) in combination with liposomal doxorubicin (Lip-Dox) in a mouse model of fibrosarcoma. Glycosphingosomes were prepared by incorporating glycosphingolipids isolated from Sphingomonas paucimobilis into the liposomes of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, cholesterol, and cardiolipin. Tumors were induced by administering dimethyl-α-benzanthracene, and tumor-bearing mice were treated with various formulations of Dox, including free Dox, Lip-Dox, or glycosphingosomes + Lip-Dox. Mice were observed for 90 days to monitor their survival and tumor size. Free Dox, but not Lip-Dox or a combination of glycosphingosomes and Lip-Dox, caused the substantial depletion of leukocytes and significantly increased the levels of lactate dehydrogenase and creatinine kinase in mice. Tumor-bearing mice treated with a combination of glycosphingosomes and Lip-Dox showed restricted tumor growth and increased survival when compared to those treated with free Dox or Lip-Dox. The results of the present study suggest that a combination of glycosphingosomes and Lip-Dox may prove to be very effective in the treatment of tumors.

Coadministration of doxorubicin and etoposide loaded in camel milk phospholipids liposomes showed increased antitumor activity in a murine model

Small unilamellar vesicles from camel milk phospholipids (CML) mixture or from 1,2 dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) were prepared, and anticancer drugs doxorubicin (Dox) or etoposide (ETP) were loaded. Liposomal formulations were used against fibrosarcoma in a murine model. Results showed a very high percentage of Dox encapsulation (~98%) in liposomes (Lip) prepared from CML-Lip or DPPC-Lip, whereas the percentage of encapsulations of ETP was on the lower side, 22% of CML-Lip and 18% for DPPC-Lip. Differential scanning calorimetry curves show that Dox enhances the lamellar formation in CML-Lip, whereas ETP enhances the nonlamellar formation. Differential scanning calorimetry curves also showed that the presence of Dox and ETP together into DPPC-Lip produced the interdigitation effect. The in vivo anticancer activity of liposomal formulations of Dox or ETP or a combination of both was assessed against benzopyrene (BAP)-induced fibrosarcoma in a murine model. Tumor-bearing mice treated with a combination of Dox and ETP loaded into CML-Lip showed increased survival and reduced tumor growth compared to other groups, including the combination of Dox and ETP in DPPC-Lip. Fibrosarcoma-bearing mice treated with a combination of free (Dox + ETP) showed much higher tumor growth compared to those groups treated with CML-Lip-(Dox + ETP) or DPPC-Lip-(Dox + ETP). Immunohistochemical study was also performed to show the expression of tumor-suppressor PTEN, and it was found that the tumor tissues from the group of mice treated with a combination of free (Dox + ETP) showed greater loss of cytoplasmic PTEN than tumor tissues obtained from the groups of mice treated with CML-Lip-(Dox + ETP) or DPPC-Lip-(Dox + ETP).

Genotyping, morphology and molecular characteristics of a lytic phage of Neisseria strain obtained from infected human dental plaque

The lytic bacteriaphage (phage) A2 was isolated from human dental plaques along with its bacterial host. The virus was found to have an icosahedron-shaped head (60±3 nm), a sheathed and rigid long tail (∼175 nm) and was categorized into the family Siphoviridae of the order Caudovirales, which are dsDNA viral family, characterised by their ability to infect bacteria and are nonenveloped with a noncontractile tail. The isolated phage contained a linear dsDNA genome having 31,703 base pairs of unique sequence, which were sorted into three contigs and 12 single sequences. A latent period of 25 minutes and burst size of 24±2 particles was determined for the virus. Bioinformatics approaches were used to identify ORFs in the genome. A phylogenetic analysis confirmed the species inter-relationship and its placement in the family.

Anti-hepatitis B activity of isoquinoline alkaloids of plant origin

Hepatitis B virus (HBV) is the causative agent of B-type hepatitis in humans, a vaccine-preventable disease. Despite the availability of effective vaccines, globally, 2 billion people show evidence of past or current HBV infection, of which 350 million people are persistently infected, with an estimated annual increase of 1 million. There is no cure for chronic HBV infections, which are associated with cirrhotic liver failure and with an increased risk of developing hepatocellular carcinoma. Hepatitis antiviral research has focused primarily on the development of inhibitors of viral polymerase through the use of nucleoside analogues. Therefore, there is an urgent need for the development of non-nucleoside compounds to be used as an alternative or to complement the current therapy. To address this need, 18 isoquinoline alkaloids were evaluated for their potential antiviral activity against HBV in vitro.