Antennapedia-derived positively-charged peptide faces multiple problems upon their usage as targeting ligand for liposomal doxorubicin.

The positively-charged peptide antp derived from Antennapedia transcription protein is demonstrated to mediate the liposome translocation across the cell membrane. In the current investigation, we prepared a stable liposomal doxorubicin (Dox) formulation and targeted it with the antp peptide from 0 to 200 ligand/liposome. These antp-containing liposomes were investigated in terms of physical stability on storage in the refrigerator and upon incubation in blood. Also, other features like cell binding, uptake, biodistribution, and treatment efficiency were evaluated in C26 colon carcinoma BALB/c mice. The Antp in liposomes resulted in enhanced particle growth with the development of the enormously large liposomes from 2000 to 6000 nm. Upon incubation in blood, these large liposomes were removed. The antp also enhanced the cell binding affinity and cell uptake rate of the liposomes and resulted in the restriction of the cancer cell proliferation, but it failed to improve the chemotherapeutic property of the Dox-liposome. The i.v. injection of antp-liposomes (15 mg Dox/kg) caused severe body weight loss and early death incidence due to probably increased toxicity. The antp targeting offered no advantage to the Dox-liposome in the delivery of Dox to the tumor, and failed to enhance the treatment efficiency of the liposomes.

Nanoliposomal vaccine containing long multi-epitope peptide E75-AE36 pulsed PADRE-induced effective immune response in mice TUBO model of breast cancer.

The main goal of peptide-based cancer vaccines is to induce the immune system and activation of effective T cell responses against cancerous cells. Nevertheless, the potency of peptide vaccines is insufficient in most of cases and had limited clinical success. Therefore, the optimization of peptide-based cancer vaccine is essential to achieve powerful therapeutic outcomes. One strategy to enhanced potency of peptide vaccines and induce strong immune responses is the preparation of multi-epitope peptide formulation containing both Th- and cytotoxic T lymphocyte-induced responses epitope using suitable delivery system. For this reason, we studied the effect of Dioleoylphosphatidylethanolamine-containing liposomal vaccine composed of a mixture of short peptides AE36 and E75 (HER2/neu-derived peptides) and long multi-epitope peptide E75-AE36 (linkage of short peptides) in combination with a Pan HLA-DR epitope (PADRE) peptide. These formulations were examined using a series of subcutaneously injection to HER-2+ TUBO-tumoured mice in prophylactic and therapeutic model. We observed that mice vaccinated with liposomal long peptide in combination with PADRE resulted in the superior induction of CD4+ and CD8+ T cells responses and significantly enhanced production of IFN-γ compared with liposomal short peptides and non-liposomal peptides formulations. Moreover, liposome-long peptide with PADRE led to the considerable reduction of tumour growth and lifespan induction in mouse model. In conclusion, our study indicated that liposomal formulation containing long multi-epitope peptide E75-AE36 with PADRE could be used as an effective multi-epitope prophylactic/therapeutic vaccine to generate potent antigen-specific CD8+ T-cell immune response and may be introduced as a possible candidate peptide vaccine for breast cancer.

Preparation and characterization of stable nanoliposomal formulations of curcumin with high loading efficacy: In vitro and in vivo anti-tumor study.

Liposomal formulations were made using Solvent-assisted active loading technology (SALT). Two formulations composed of HSPC:DPPG:Chol:DSPE-mPEG2000 (PG-LipCUR) and HSPC:Chol:DSPE-mPEG2000 (LipCUR) demonstrated good colloidal properties and the CUR-encapsulation of 82% and 89% for PG-LipCUR and LipCUR, respectively. The results showed that both formulations were stable during 6 months storage at 4 °C. The release study showed that the PG-LipCUR and LipCUR formulations are relatively stable at pH 7.4. Both formulations had higher cytotoxicity on TUBO and 4T1 cell lines in compassion with normal cells. PG-LipCUR had the higher amounts of CUR cellular uptake than LipCUR. Biodistribution studies showed that both formulations could enhance the half-life of the CUR 2-3 times compared to free CUR. The tumor accumulation of PG-LipCUR was significantly higher than LipCUR. The antitumor activities of liposomes on 4T1 tumor model demonstrated the efficacy of both formulations compared to PBS and free CUR. PG-LipCUR also was more potent in tumor growth delay in comparison with LipCUR. However, combination of the Caelyx® and PG-LipCUR had the most antitumor properties among other treatments. Based on the results, PG-LipCUR could be a promising formulation for the delivery of CUR which also significantly increased the efficacy of Caelyx® and merits further investigation.

Cell cytotoxicity, immunostimulatory and antitumor effects of lipid content of liposomal delivery platforms in cancer immunotherapies. A comprehensive in-vivo and in-vitro study.

Liposome is one of the promising technologies for antigen delivery in cancer immunotherapies. It seems that the phospholipid content of liposomes can act as immunostimulatory molecules in cancer immunotherapy. In the present study, the immunological properties of different phospholipid content of liposomal antigen delivery platforms were investigated. To this aim, F1 to F4 naïve liposomes (without tumor-specific loaded antigens) of positively charged DOTAP/Cholesterol/DOPE (4/4/4 mol ratio), negatively charged DMPC/DMPG/Cholesterol/DOPE (15/2/3/5), negatively charged DSPC/DSPG/Cholesterol/DOPE (15/2/3/5) and PEGylated HSPC/mPEG2000-DSPE/Cholesterol (13/110) liposomal compositions were administered in mice bearing C26 colon carcinoma to assess tumor therapy. Moreover, In-vitro studies were conducted, including cytotoxicity assay, serum cytokines measurements, IFN-γ and IL-4 ELISpot assay, T cells subpopulation frequencies assay. The liposomes containing DOTAP and DOPE (F1 liposomes) were able to stimulate cytotoxic T lymphocytes signals such as IFN-γ secretions. In parallel, the aforementioned phospholipids stimulated secretion of IL-4 and IL-17 cytokines from T helper cells. However, these liposomes did not improve survival indices in mice. As conclusion, DOTAP and DOPE contained liposomes (F1 liposomes) stimulate a mixture of Th1 and Th2 immune responses in a tumor-specific antigens-free manner in mice bearing C26 colon carcinoma. Therefore, phospholipid composition of liposomes merits consideration in designing antigen-containing liposomes for cancer immunotherapy.

PNC27 anticancer peptide as targeting ligand significantly improved antitumor efficacy of Doxil in HDM2-expressing cells.

AIM: To investigate the potential of PNC27 peptide, 12-26 of p53 with high affinity for HDM2 protein, as targeting ligand for Doxil to improve its antitumor activity. MATERIALS & METHODS: Doxil postinserted with 25, 50, 100 and 200 PNC27 peptides per liposome. Flow cytometry and confocal analysis were performed on C26 colon carcinoma (HDM2 positive) and B16F0 melanoma (HDM2 negative) cells. In vivo studies were performed on BALB/c mice bearing C26 and C57BL/6 mice bearing B16F0 tumor models. RESULTS: PNC27-Doxil showed significant cellular uptake and cytotoxicity in C26 cells compared with Doxil. PNC27-Doxil (100 PNC27 peptide) significantly improved therapeutic efficacy of Doxil without compromising its biodistribution in C26 tumor. However, these results were not observed in B16F0 cells. CONCLUSION: PNC27 is a promising targeting ligand for Doxil against HDM2-positive cancers.