A new hexapeptide from the leader peptide of rMnSOD enters cells through the oestrogen receptor to deliver therapeutic molecules.

A 24-amino acid leader peptide of a new human recombinant manganese superoxide dismutase can enter cells and carry molecules. Here, we demonstrated that six of the 24 amino acids penetrate cells through a particular gate represented by a specific amino acid sequence of the oestrogen receptor (ER). We analysed the internalization of the synthetic hexapeptide and the cytotoxic activity of the hexapeptide conjugated to cisplatin on a cell line panel. In most cell lines, the hexapeptide delivered an amount of cisplatin that was 2 to 8 times greater than that released by cisplatin when the drug was used alone. This increased delivery increases the therapeutic index of cisplatin and reduces side effects caused by a high dosage or long-term treatment times. We may consider this hexapeptide a new molecular carrier to deliver molecules with therapeutic activity into ER(+) cells for diagnostic purposes and clinical or immune therapy.

CDK/CCN and CDKI alterations for cancer prognosis and therapeutic predictivity.

The regulation of cell growth and division occurs in an accurate sequential manner. It is dictated by the accumulation of cyclins (CCNs) and cyclin-dependent kinases (CDKs) complexes and degradation of CCNs. In human tumors, instead, the cell cycle is deregulated, causing absence of differentiation and aberrant cell growth. Oncogenic alterations of CCNs, CDKs, and CDKIs have been reported in more than 90% of human cancers, and the most frequent are those related to the G1 phase. Several molecular mechanisms, including gene overexpression, chromosomal translocations, point mutations, insertions and deletions, missense and frame shift mutation, splicing, or methylation, may be responsible for these alterations. The cell cycle regulators are involved in tumor progression given their association with cancers characterized by higher incidence of relapses and chemotherapy resistance. In the last decade anticancer drug researches focused on new compounds, able to target molecules related to changes in genes associated with tumor status. Recently, the studies have focused on the restoration of cell cycle control modulating molecular targets involved in cancer-cell alterations. This paper aims to correlate alterations of cell cycle regulators with human cancers and therapeutic responsivity.

The functional role of MnSOD as a biomarker of human diseases and therapeutic potential of a new isoform of a human recombinant MnSOD.

Reactive oxygen species (ROS) are generated as a consequence of metabolic reactions in the mitochondria of eukaryotic cells. This work describes the role of the manganese superoxide dismutase (MnSOD) as a biomarker of different human diseases and proposes a new therapeutic application for the prevention of cancer and its treatment. The paper also describes how a new form of human MnSOD was discovered, its initial application, and its clinical potentials. The MnSOD isolated from a human liposarcoma cell line (LSA) was able to kill cancer cells expressing estrogen receptors, but it did not have cytotoxic effects on normal cells. Together with its oncotoxic activity, the recombinant MnSOD (rMnSOD) exerts a radioprotective effect on normal cells irradiated with X-rays. The rMnSOD is characterized by the presence of a leader peptide, which allows the protein to enter cells: this unique property can be used in the radiodiagnosis of cancer or chemotherapy, conjugating radioactive substances or chemotherapic drugs to the leader peptide of the MnSOD. Compared to traditional chemotherapic agents, the drugs conjugated with the leader peptide of MnSOD can selectively reach and enter cancer cells, thus reducing the side effects of traditional treatments.

A molecular carrier to transport and deliver cisplatin into endometrial cancer cells.

The leader peptide of a recombinant manganese superoxide dismutase (rMnSOD-Lp) acts as a molecular carrier. Clonogenic tests on normal (MRC-5) and endometrial adenocarcinoma cells (HTB-112) were carried out in the presence of rMnSOD-Lp, cisplatin alone (CC) or cisplatin conjugated to the rMnSOD-Lp (rMnSOD-Lp-CC). The platinum delivered into the cells was measured by atomic spectrophotometric absorbance. The treatments on tumor and normal cells were finally evaluated by LM and TM microscopy. Tumor cell death in the case of 0.5 µM cisplatin on its own was minimal, while in the presence of 0.5 µM rMnSOD-Lp-CC, no tumor cells survived. Atomic absorbance analysis showed that rMnSOD-Lp-CC delivered approximately four times more cisplatin into HTB-112 cells than the amount delivered using cisplatin alone. By LM observation, the cells treated with rMnSOD-Lp-CC showed signs of nuclear and cytoplasmic fragmentation, that is, apoptosis induced by the treatment. The therapeutic effect of rMnSOD-Lp-CC on endometrial cancer cells was significant, while on the normal cells it showed only a minimal toxicity. We believe that rMnSOD-Lp deserves to be considered as a molecular carrier to deliver cisplatin directly into tumor cells, thus transforming its antireplicative activity into a specific and selective antitumor agent.

The leader peptide of a human rec. MnSOD as molecular carrier which delivers high amounts of Cisplatin into tumor cells inducing a fast apoptosis in vitro.

The leader peptide of a recombinant MnSOD (rMnSOD-Lp) constitutes the carrier that allows rMnSOD to penetrate tumor cells. A synthetic preparation of rMnSOD-Lp was 68Ga labeled (rMnSOD-Lp- 68Ga) and injected into animals bearing spontaneous mammary cancers, followed by PET examinations, which demonstrated unambiguously the tumor sites in all the animals, suggesting that if rMnSOD-Lp was able to transport the radioisotope into tumor cells, it would also be able to deliver cytotoxic molecules. The rMnSOD-Lp was, therefore, conjugated to cisplatin (rMnSOD-Lp-CC) and added to cultured tumor cells. Equal concentrations of cisplatin were used for the tests. After treating the ovarian cancer cells with 11.1 µg of cisplatin alone, analysis by atomic absorbance spectrophotometry was able to detect only 6 ng of platinum, whereas when the same cells were treated with the same amount of cisplatin conjugated to leader peptide rMnSOD, 387 ng of platinum were detected, i.e., an amount 80 times greater. Only the tumor cells died following treatment with rMnSOD-Lp-CC; molecular analysis revealed that its addition generated an increasing expression of Erk-2 and Bax products, which could be inhibited only by a selective MAP/ERK kinase inhibitor (PD98059), revealing that rMnSOD-Lp-CC has an apoptotic function, exactly as occurs when using the cisplatin alone. Data are statistically significant and indicate that by using rMnSOD-Lp-CC, the cisplatin can be transformed from an agent with antireplicative activity into a specific and selective antitumor molecule, increasing its therapeutic index. We think that rMnSOD-Lp-CC deserves to be considered as a new antitumor agent.