AaTs-1: A Tetrapeptide from Androctonus australis Scorpion Venom,Inhibiting U87 Glioblastoma Cells Proliferation by p53 and FPRL-1 Up-Regulations

Glioblastoma is an aggressive cancer, against which medical professionals are still quite helpless, due to its resistance to current treatments. Scorpion toxins have been proposed as a promising alternative for the development of effective targeted glioblastoma therapy and diagnostic. However, the exploitation of the long peptides could present disadvantages. In this work, we identified and synthetized AaTs-1, the first tetrapeptide from Androctonus australis scorpion venom (Aa), which exhibited an antiproliferative effect specifically against human glioblastoma cells. Both the native and synthetic AaTs-1 were endowed with the same inhibiting effect on the proliferation of U87 cells with an IC₅₀ of 0.56 mM. Interestingly, AaTs-1 was about two times more active than the anti-glioblastoma conventional chemotherapeutic drug, temozolomide (TMZ), and enhanced its efficacy on U87 cells. AaTs-1 showed a significant similarity with the synthetic peptide WKYMVm, an agonist of a G-coupled formyl-peptide receptor, FPRL-1, known to be involved in the proliferation of glioma cells. Interestingly, the tetrapeptide triggered the dephosphorylation of ERK, p38, and JNK kinases. It also enhanced the expression of p53 and FPRL-1, likely leading to the inhibition of the store operated calcium entry. Overall, our work uncovered AaTs-1 as a first natural potential FPRL-1 antagonist, which could be proposed as a promising target to develop new generation of innovative molecules used alone or in combination with TMZ to improve glioblastoma treatment response. Its chemical synthesis in non-limiting quantity represents a valuable advantage to design and develop low-cost active analogues to treat glioblastoma cancer.     

Algebraic analysis of a RGB image encryption algorithm based on DNA encoding and chaotic map

Recently a new image encryption method based on DNA encoding and chaotic systems has been proposed. In this paper, several weaknesses of this cryptosystem are pointed out. Equivalent mathematical model of the cryptosystem is designed and algebraic analysis is given. Moreover reduction of the key space has been reached by finding equivalent keys. A recovering scheme is finally given with a lower complexity than the actual decryption scheme.