Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Peptide containing doai
Patent
1995-06-01
1997-06-17
Krass, Frederick
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Peptide containing doai
530351, C07K 100, C07K 1400, C07K 1700
Patent
active
056397283
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a novel antineoplastic peptide.
BACKGROUND ART
Previously known antineoplastic peptides include TNF and lymphotoxin. TNF is problematic in that hypotension is a side effect and application in actual therapies is currently limited; likewise, lymphotoxin also has a hypotensive effect, and manufacture of recombinant lymphotoxin has drawbacks. Thus, at present, the research on lymphotoxin is not progressing well.
Heretofore, there have been various reports regarding derivatives comprising modified native-form lymphotoxin peptides. Examples include JP, A, S63-8398, JP, A, S63-8399, JP, A, S63-270698, JP, A, S64-6298, JP, A, S64-29399, JP, A, H3-184994, and JP, A, H4-45789.
However, such previously reported lymphotoxin derivatives (hereinafter referred to "LT derivatives") exhibit a hypotensive effect similar to that seen in TNF, and thus, in this respect, there is a problem to be solved.
As a result of extensive research involving various investigations on conventional LT derivatives, by means of the present invention, the present inventor succeeded in offering a novel peptide possessing an excellent antineoplastic effect.
DISCLOSURE OF THE INVENTION
The present invention offers a novel peptide possessing the amino acid sequence described by the following formula (I) (Provided, R indicates Met or H.). ##STR1## The present invention also concerns usage in an antitumor agent containing such a peptide as an active ingredient.
The novel peptide pertaining to the present invention shows no hypotensive effect at an effective quantity showing antitumor activity, and in terms of antitumor activity, said peptide is also known to manifest the exceptional value of the chemotherapeutic index, seven times that of TNF. Consequently, the novel peptide pertaining to the present invention is extremely useful from the standpoint that it can be used in a drug serving as an antitumor agent.
The novel antineoplastic peptide pertaining to the present invention is obtained by expressing the peptide by means of DNA prepared by incorporating the modified LT gene into an expression vector. The modified LT gene was prepared as follows. Starting from a native-form human lymphotoxin (LT) gene, the DNA of a 10 amino acid segment (30 bases) has been removed from the N-terminal end segment of this DNA sequence, and DNA corresponding to Met, Phe, Pro or Phe, Pro amino acid sequence has been added. This peptide, namely, a peptide wherein the above-noted Phe and Pro amino acid sequence has been incorporated, is hereinafter denoted by "FP.DELTA.10LT."
Specifically, the above-mentioned DNA can be assembled through the procedures shown in FIG. 1, for example. Through the method shown in FIG. 1, a vector expressing the peptide pertaining to the present invention can be assembled by cutting out a base sequence which codes the ribosome binding site (segment SD domain (gene 1)) and a base sequence which codes most of an LT structural gene (gene 2) from a well-known modified LT vector discussed hereafter, and ligating said sequences with a base sequence synthesized so as to include an initiator codon and an amino acid sequence (synthesis gene) and a vector (gene 3).
The modified LT vector (hereinafter referred to "pBtrp MLT") used in the procedures shown in FIG. 1 is essentially that developed by Seow et al. (Biotechnology 7, 363 [1989]) and somewhat modified by Morita et al. (JP, A, H4-45789). The use of this vector allows advantageous expression of lymphotoxins. This vector can be assembled by using a promoter in which the -10 region base sequence is TTAACT and the -35 region base sequence is TTGACA, establishing 13 bases between the SD domain (ribosome binding site) and the initiator codon (ATG). The lymphotoxin gene was then ligated to this DNA. The length of the vector DNA was 2.7-3.1 kb.
By using a modified LT vector obtained in the aforementioned manner to genetically transform a host microorganism according to a routine method, then culturing the genetically transformed microorganism
REFERENCES:
Biotechnology vol. 7, Apr. 1989, pp. 363-368.
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