Keyhole limpet hemocyanin potentiates standard immunotherapy for melanoma

Therapeutic potential of marine peptides in malignant melanoma

Malignant melanoma is the most dangerous type of skin cancer. It is becoming more common globally and is increasingly resistant to treatment options. Despite extensive research into its pathophysiology, there are still no proven cures for metastatic melanoma. Unfortunately, current treatments are frequently ineffective and costly, and have several adverse effects. Natural substances have been extensively researched for their anti-MM capabilities. Chemoprevention and adjuvant therapy with natural products is an emerging strategy to prevent, cure or treat melanoma. Numerous prospective drugs are found in aquatic species, providing a plentiful supply of lead cytotoxic chemicals for cancer treatment. Anticancer peptides are less harmful to healthy cells and cure cancer through several different methods, such as altered cell viability, apoptosis, angiogenesis/metastasis suppression, microtubule balance disturbances and targeting lipid composition of the cancer cell membrane. This review addresses marine peptides as effective and safe treatments for MM and details their molecular mechanisms of action.

Formulation of abalone hemocyanin with high antiviral activity and stability

Hemocyanin has been shown to have potential antiviral activity against herpes simplex virus type-1. However, current liquid formulations have short shelf life and high risk of bacterial contamination. The aim of our study was to develop a stable functional formulation. Analytical techniques (nano-differential scanning calorimetry and spectroscopy) and biological assays (cytotoxicity and plaque reduction) were employed to measure the effect of sugar addition on the physical properties and shelf life of the solid formulated hemocyanin. Sucrose improved thermal stability significantly by both increasing the aggregation onset temperature (70°C to>78 °C) and enhancing the activation energy (18%). Lyophilisation without trehalose caused degradation and unfolding of the α-helices of hemocyanin. However, the addition of an optimal proportion of trehalose:protein (5:1 by weight) prevented the degradation and unfolding during lyophilisation, hence maintained the protein solubility. The estimated ED50 values of the formulated solid (0.43±0.1) and liquid samples (0.37±0.06) were similar in magnitude, and were significantly lower than the respective controls; thus, confirming enhanced antiviral activity of the formulation. Formulated compounds were stable for six months at 5 °C storage. The enhanced shelf life and stable antiviral activity of the formulation offers its significant potential as effective therapeutic agent in future clinical applications.

Involvement of glycan chains in the antigenicity of Rapana thomasiana hemocyanin

Functional unit (FU) RtH2-e from Rapana thomasiana hemocyanin (Hc) was degraded into small fragments with chymotrypsin. The glycopeptides were separated from the non-glycosylated peptides by chromatography on Concanavalin-A-Sepharose and characterized by mass spectrometry. The glycan part of the glycopeptides (all with common peptide stretch of 14 amino acids) consists of the classical trimannosyl-N,N-diacetylchitobiose core for N-glycosylation, predominantly extended with a unique tetrasaccharide that is branched on fucose. In inhibition ELISA experiments, the glycopeptides interfered in the complex formation between FU RtH2-e and rabbit antibodies against Rapana Hc (about 30% of inhibition). The inhibition also was retained after treatment of the glycopeptides with pronase in order to completely destroy the peptide part. The inhibitory effect of the non-glycosylated peptides, on the other hand, was very low. This study thus demonstrates that the glycans attached to FU RtH2-e contribute to the antigenicity of Rapana Hc.