Nucleic acid simultaneously inhibiting expression of mTOR gene and STAT3 gene

Abstract

The present invention relates to a nucleic acid molecule simultaneously inhibiting the expression of mTOR gene and STAT3 gene, and an anticancer pharmaceutical composition comprising the same. More specifically, base-paired siRNA or shRNA of the present invention, designed to simultaneously inhibit the expression of cancer-related mTOR gene and STAT3 gene in order to surmount the problem that siRNA or shRNA does not achieve high therapeutic effects due to the target specificity thereof, has the effect of promoting the death of cancer cells. In addition, the nucleic acid has the effect of synergistically enhancing the apoptosis of cancer cells when used in combination with an anticancer agent, finding useful applications as an anticancer composition or anticancer aid against various carcinomas.

Claims

1. A siRNA or shRNA simultaneously inhibiting the expression of mammalian target of rapamycin (mTOR) gene and signal transducer and activator of transcription 3 (STAT3) gene, wherein the siRNA or shRNA comprises the sequences represented by SEQ ID NOs: 1 and 2; SEQ ID NOS: 3 and 4; SEQ ID NOS: 5 and 6; SEQ ID NOS: 7 and 8; SEQ ID NOS: 9 and 10; SEQ ID NOS: 11 and 12; SEQ ID NOS: 13 and 14; SEQ ID NOS: 15 and 16; or SEQ ID NOs: 17 and 18.

2. The siRNA or shRNA of claim 1, wherein the sequences represented by SEQ ID NOS: 1, 3, 5, 7, 9, 11, 13, 15 and 17 inhibit the mTOR gene expression by RNA interference.

3. The siRNA or shRNA of claim 1, wherein the sequences represented by SEQ ID NOS: 2, 4, 6, 8, 10, 12, 14, 16 and 18 inhibit the STAT3 gene expression by RNA interference.

4. A nucleic acid molecule encoding a shRNA which simultaneously inhibits the expression of mammalian target of rapamycin (mTOR) gene and signal transducer and activator of transcription 3 (STAT3) gene, the nucleotide sequence comprises the sequence of SEQ ID NO: 20 or SEQ ID NO: 21.

5. A recombinant expression vector expressing the siRNA or shRNA of claim 1.

6. A recombinant microorganism into which the recombinant expression vector of claim 5 is transfected.

7. A pharmaceutical composition for anticancer, the composition comprising the siRNA or shRNA of claim 1 as an active ingredient.

8. The pharmaceutical composition of claim 7, wherein the composition further comprises an anticancer agent.

9. The pharmaceutical composition of claim 8, wherein the anticancer agent is at least one anticancer agent selected from the group consisting of cisplatin, paclitaxel, 5-fluorouracil (5-FU), methotrexate, doxorubicin, daunorubicin, cytosine arabinoside, etoposide, melphalan, chlorambucil, cyclophosphamide, vindesine, mitomycin, bleomycin, tamoxifen, and taxol.

Description

DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a view showing a vector map for expressing shRNAs in a cell, in which the shRNAs include a double-stranded siRNA sequence of the present invention together with a loop sequence in one strand.

(2) FIG. 2 is a view showing the effect of the double-stranded siRNA of the double target of the present invention to inhibit the expression of mTOR or STAT3 gene.

(3) FIG. 3 is a view showing the expression level of mTOR and STAT3 by treating mTOR gene or STAT3 gene with siRNA, respectively or together, in order to verify mutual influence of expression of mTOR gene and STAT3 gene (nc2 is a control siRNA; simTOR is a siRNA targeting the only mTOR; siSTAT3 is a siRNA targeting the only STAT3; and simTOR & STAT3 is co-treated with siRNA targeting mTOR and siRNA targeting STAT3).

(4) FIG. 4 is a view showing the cell survival rate of A549 cells, human lung cancer cell line, when the double target siRNA of the present invention simultaneously inhibits mTOR and STAT3.

(5) FIG. 5 is a view showing the cell survival rate of A549 cells, human lung cancer cell line, when the double target siRNA of the present invention simultaneously inhibits mTOR and STAT3 after treating with cisplatin.

(6) FIG. 6 is a view showing the cell survival rate of A549 cells, human lung cancer cell line, when the double target siRNA of the present invention simultaneously inhibits mTOR and STAT3 after treating with paclitaxel.

(7) FIG. 7 is a view showing the cell survival rate of A549 cells, human lung cancer cell line, when the double target siRNA of the present invention simultaneously inhibits mTOR and STAT3 after treating with 5-fluorouracil (5-FU).

(8) FIG. 8 is a view showing the expression amount of mTOR and STAT3 according to the DNA amount of shRNA by a vector including TTGGATCCAA loop shRNA sequence represented by SEQ ID NO: 20 or TTCAAGAGAG loop shRNA represented by SEQ ID NO: 21.

MODES OF THE INVENTION

(9) The present invention provides a nucleic acid molecule that simultaneously inhibits the expression of mTOR and STAT3 gene.

(10) The nucleic acid molecule may include the nucleotide sequence represented by SEQ ID NOS: 1 and 2; SEQ ID NOS: 3 and 4; SEQ ID NOS: 5 and 6; SEQ ID NOS: 7 and 8; SEQ ID NOS: 9 and 10; SEQ ID NOS: 11 and 12; SEQ ID NOS: 13 and 14; SEQ ID NOS: 15 and 16 or SEQ ID NOs: 17 and 18.

(11) In an embodiment, the nucleotide sequence represented by SEQ ID NOS: 1, 3, 5, 7, 9, 11, 13, 15 and 17 may inhibit the mTOR gene expression by RNA interference, and the nucleotide sequence represented by SEQ ID NOS: 2, 4, 6, 8, 10, 12, 14, 16 and 18 may inhibit the STAT3 gene expression by RNA interference and thus the nucleic acid molecule of the present invention may simultaneously inhibit the expression of mTOR and STAT3 gene.

(12) In an embodiment, it was confirmed that SEQ ID NOS: 1 and 2; SEQ ID NOS: 3 and 4; SEQ ID NOS: 5 and 6; SEQ ID NOS: 7 and 8; SEQ ID NOS: 9 and 10; SEQ ID NOS: 11 and 12; SEQ ID NOS: 13 and 14; SEQ ID NOS: 15 and 16; and SEQ ID NOS: 17 and 18, respectively, are designed to be partially complementarily linked to form a double-stranded siRNA, and the double-stranded siRNA targets each of mTOR gene and STAT3 gene to inhibit their expression, thereby verifying that they are double target siRNA set.

(13) In the present invention, the siRNA targeting mTOR or STAT3 has 100% complementary sequence with a part of the mTOR gene or the STAT3 gene of human (Homo sapiens) and may degrade mRNA of mTOR gene or STAT3 gene or inhibit its translation.

(14) As used herein, the term “inhibition of expression” means to lead decline in the expression or translation of a target gene, and preferably means that accordingly the expression of the target gene becomes undetectable or resultantly exists at the meaningless level.

(15) As used herein, the term, “small interfering RNA (siRNA)” means short double-stranded RNA capable of inducing RNA interference (RNAi) phenomenon by cleavage of a specific mRNA. Generally, the siRNA consists of a sense RNA strand having a sequence homologous to the mRNA of the target gene and an antisense RNA strand having a complementary sequence thereof. However, in the double-stranded siRNA of the present invention, the sense RNA strand is siRNA (antisense strand to the mTOR gene) consisting of the nucleotide sequences represented by SEQ ID NOS: 1, 3, 5, 7, 9, 11, 13, 15 and 17, and the antisense RNA strand is siRNA (antisense strand to the STAT3 gene) consisting of the nucleotide sequences represented by SEQ ID NOS: 2, 4, 6, 8, 10, 12, 14, 16 and 18 so that the double-stranded siRNA may simultaneously inhibit the expression of the mTOR and the STAT3 gene, respectively. Thus, it can be provided as an efficient method of gene knock-down or gene therapy.

(16) In an embodiment, 17mer of 21mers in siRNA represented by SEQ ID NOS: 1 and 2 of Set 1, 16mer of 20mer in siRNA represented by SEQ ID NOS: 3 and 4 of Set 2, 15mer of 19mer in siRNA represented by SEQ ID NOS: 5 and 6 of Set 3, 14mer of 18mer in siRNA represented by SEQ ID NOS: 7 and 8 of Set 4, and 16mer of 17mer in siRNA represented by SEQ ID NOS: 9 and 10 of Set 5 are complementarily linked. Further, 17mer of 20mer in siRNA represented by SEQ ID NOS: 11 and 12 of Set 6, 16mer of 19mer in siRNA represented by SEQ ID NOS: 13 and 14 of Set 7, 15mer of 18mer in siRNA represented by SEQ ID NOS: 15 and 16 of Set 8, and 15mer of 17mer in siRNA represented by SEQ ID NOS: 17 and 18 of Set 9 are complementarily linked.

(17) Variants of the above nucleotide sequences are included within the scope of the present invention. The nucleic acid molecule of the present invention, which simultaneously inhibits the mTOR and STAT3 gene expression, is used as a concept that includes a functional equivalent of a nucleic acid molecule constituting the nucleic acid molecule, for example, the variant which is capable of performing same function to the nucleic acid molecule although it is modified by the deletion, substitution, or insertion of partial nucleotide sequences of the nucleic acid molecule. Specifically, the gene may include the nucleotide sequence having at least 70%, more preferably at least 80%, even more preferably at least 90%, most preferably at least 95% sequence homology with each nucleotide sequence represented by SEQ ID NOS: 1 to 18. The term “sequence homology percent” to a nucleic acid molecule is determined by comparing the two optimally arranged sequences with the comparison region, and some of the nucleic acid molecule sequences in the comparison region may include addition or deletion (e.g., gap) compared with the reference sequence (without addition or deletion) to the optimal arrangement of the two sequences.

(18) Further, the present invention provides a recombinant expression vector including the nucleic acid molecule.

(19) In order to appropriately transcript the double-stranded siRNA targeting mTOR and STAT3 in target cells in the present invention, it is preferable that the siRNA-containing shRNA, particularly shRNA having a partially modified nucleotide sequence, which is represented by SEQ ID NOS: 1 to 18, is at least operatively linked to the promoter. The promoter may be any one which is capable of functioning in eukaryotic cells. In order to efficiently transcript double-stranded siRNA or shRNA targeting mTOR and STAT3, regulatory sequences may be further included as needed, in which the regulatory sequences include leader sequences, polyadenylation sequences, promoters, enhancers, upstream activation sequences, signal peptide sequences and transcription termination factors. The shRNA may be represented by the nucleotide sequence represented by SEQ ID NO: 20 or 21.

(20) As used herein, the term “short hairpin RNA (shRNA)” means RNA in which single-stranded RNA may partially contain nucleotide sequences having palindrome to form a double-stranded structure in the 3′-region, thereby having a hairpin-like structure, and after expression in cells, it may be cleaved by dicer, which is one type of RNase present in cells to be converted into siRNA. The length of the double-stranded structure is not particularly limited, but is preferably 10 nucleotides or more, and more preferably 20 nucleotides or more. In the present invention, the shRNA may be included in a vector.

(21) As used herein, the term “vector” means a means for expressing a target gene in a host cell, in which it may include plasmid vectors; phagemid vectors; cosmid vectors; and viral vectors such as bacteriophage vectors, adenovirus vectors, retroviral vectors, and adeno-associated viral vectors.

(22) According to a preferred embodiment of the present invention, the gene in the vector of the present invention is operatively linked to a promoter.

(23) As used herein, the term “operably linked” refers to a functional linkage between a gene expression regulatory sequence (e.g., an array of binding site of promoter, signal sequence, or transcription factor) and different gene sequences, and accordingly, the regulatory sequence regulates the transcription and/or translation of the different gene sequences.

(24) The vector system of the present invention may be constructed by various manners known in the art, and these specific manners are disclosed in Sambrook et al. (2001), Molecular Cloning, A Laboratory Manual, Cold Spring Harbor Laboratory Press, and this document is incorporated herein by reference.

(25) The vector of the present invention may typically be constructed as a cloning vector or as an expression vector. Further, the vector of the present invention may be constructed by using a prokaryotic cell or eukaryotic cell as a host. When the vector of the present invention is an expression vector, and a prokaryotic cell is used as a host, it generally includes a strong promoter capable of promoting transcription (e.g., tac promoter, lac promoter, lacUV5 promoter, lpp promoter, pLλ promoter, pRλ promoter, rac5 promoter, amp promoter, recA promoter, SP6 promoter, trp promoter and T7 promoter), a ribosome binding site for initiation of translation and a transcription/translation termination sequence. When E. coli. (e.g., HB101, BL21, DH5α) is used as a host cell, the promoter and operator site of the E. coli tryptophan biosynthetic pathway (Yanofsky, C. (1984), J. Bacteriol., 158: 1018-1024) and the left promoter of phage λ (pLλ promoter, Herskowitz, I. and Hagen, D. (1980), Ann Rev. Genet., 14: 399-445) may be used as a regulatory site.

(26) Meanwhile, the vector that may be used for the present invention can be manufactured by manipulating a plasmid (for example, pSC101, pGV1106, pACYC177, ColE1, pKT230, pME290, pBR322, pUC8/9, pUC6, pBD9, pHC79, pIJ61, pLAFR1, pHV14, pGEX series, pET series, pUC19, and the like), a phagemid (for example, pComb3X), a phage or a virus (for example, SV40 or the like) often used in the art.

(27) Meanwhile, when the vector of the present invention is an expression vector, and a eukaryotic cell is used as a host, a promoter derived from a genome of a mammalian cell (for example, a metallothionein promoter) or a promoter derived from a mammalian virus (for example, adenovirus late promoter, vaccinia virus 7.5K promoter, SV40 promoter, cytomegalovirus promoter and HSV tk promoter) can be used, and it generally contains a polyadenylation sequence as a transcription termination sequence.

(28) In order to readily purify protein, the vector of the present invention may be fused with other sequences as needed. The fusion sequence includes, for example, glutathione S-transferase (Pharmacia, USA), maltose binding protein (NEB, USA), FLAG (IBI, USA), and 6×His (hexahistidine; Quiagen, USA), but is not limited thereto. Further, the expression vector of the present invention may include an antibiotic resistance gene commonly used in the art as a selection marker, and the resistance gene includes, for example, resistance genes against ampicillin, gentamycin, carbenicillin, chloramphenicol, streptomycin, kanamycin, geneticin, neomycin and tetracycline.

(29) Further, the present invention provides a recombinant microorganism into which the recombinant expression vector is transfected.

(30) Any kind of a host cell known in the pertinent art can be used if stable and continuous cloning and expression of the vector of the present invention can be achieved by using it. Examples include a prokaryotic host cell including strains belonging to the genus Bacillus such as Escherichia coli, Bacillus subtilus and Bacillus thuringiensis, Streptomyces, Pseudomonas (for example, Pseudomonas putida), Proteus mirabilis or Staphylococcus (for example, Staphylococcus carnosus), but is not limited thereto. The host cell is preferably E. coli, and more preferably E. coli ER2537, E. coli ER2738, E. coli XL-1 Blue, E. coli BL21(DE3), E. coli JM109, E. coli DH series, E. coli TOP10, E. coli TG1 and E. coli HB101.

(31) Methods of transfecting the vector of the present invention into a host cell may be carried out by the CaCl2 method (Cohen, S N et al. (1973), Proc. Natl. Acac. Sci. USA, 9: 2110-2114), Hanahan's method (Cohen, S. N. et al. (1973), Proc. Natl. Acac. Sci. USA, 9:2110-2114; and Hanahan, D. (1983), J. Mol. Biol., 166:557-580), an electroporation method (Dower, W. J. et al. (1988), Nucleic Acids Res., 16: 6127-6145) and the like.

(32) Further, the present invention provides a pharmaceutical composition for anticancer, in which the composition includes the nucleic acid molecule as an active ingredient.

(33) The nucleic acid molecule may further include an anticancer agent, for example, acivicin, aclarubicin, acodazole, achromycin, adozelesin, alanosine, aldesleukin, allopurinol sodium, altretamine, aminoglutethimide, amonafide, ampligen, amsacrine, androgens, anguidine, aphidicolin glycinate, asaley, asparaginase, 5-azacitidine, azathioprine, Bacillus Calmette-Guerin (BCG), Baker's antifol, β-2-deoxythioguanosine, bisantrene HCl, bleomycin sulfate, busulfan, buthionine sulfoximine, BWA 773U82, BW 502U83.HCl, BW 7U85 mesylate, ceracemide, carbetimer, carboplatin, carmustine, chlorambucil, chloroquinoxaline-sulfonamide, chlorozotocin, chromomycin A3, cisplatin, cladribine, corticosteroids, Corynebacterium parvum, CPT-11, crisnatol, cyclocytidine, cyclophosphamide, cytarabine, cytembena, dabis maleate, dacarbazine, dactinomycin, daunorubicin HCl, deazauridine, dexrazoxane, dianhydrogalactitol, diaziquone, dibromodulcitol, didemnin B, diethyldithiocarbamate, diglycoaldehyde, dihydro-5-azacytidine, doxorubicin, echinomycin, dedatrexate, edelfosine, eflornithine, Elliott's solution, elsamitrucin, epirubicin, esorubicin, estramustine phosphate, estrogens, etanidazole, ethiofos, etoposide, fadrazole, fazarabine, fenretinide, filgrastim, finasteride, flavone acetic acid, floxuridine, fludarabine phosphate, 5′-fluorouracil, Fluosol™, flutamide, gallium nitrate, gemcitabine, goserelin acetate, hepsulfam, hexamethylene bisacetamide, homoharringtonine, hydrazine sulfate, 4-hydroxyandrostenedione, hydrozyurea, idarubicin HCl, ifosfamide, 4-ipomeanol, iproplatin, isotretinoin, leucovorin calcium, leuprolide acetate, levamisole, liposome daunorubicin, liposome-encapsulated doxorubicin, lomustine, lonidamine, maytansine, mechlorethamine hydrochloride, melphalan, menogaril, merbarone, 6-mercaptopurine, mesna, methanol extraction of Bacillus Calmette-Guerin, methotrexate, N-methylformamide, mifepristone, mitoguazone, mitomycin-C, mitotane, mitoxantrone hydrochloride, monocyte/macrophage colony-stimulating factor, nabilone, nafoxidine, neocarzinostatin, octreotide acetate, ormaplatin, oxaliplatin, paclitaxel, pala, pentostatin, piperazinedione, pipobroman, pirarubicin, piritrexim, piroxantrone hydrochloride, PIXY-321, plicamycin, porfimer sodium, prednimustine, procarbazine, progestins, pyrazofurin, razoxane, sargramostim, semustine, spirogermanium, spiromustine, streptonigrin, streptozocin, sulofenur, suramin sodium, tamoxifen, taxotere, tegafur, teniposide, terephthalamidine, teroxirone, thioguanine, thiotepa, thymidine injection, tiazofurin, topotecan, toremifene, tretinoin, trifluoperazine hydrochloride, trifluridine, trimetrexate, tumor necrosis factor (TNF), uracil mustard, vinblastine sulfate, vincristine sulfate, vindesine, vinorelbine, vinzolidine, Yoshi 864, zorubicin, cytosine arabinoside, etoposide, melphalan, taxol and mixtures thereof. It includes preferably cisplatin, paclitaxel, 5-fluorouracil (5-FU), methotrexate, doxorubicin, daunorubicin, cytosine arabinoside, etoposide, melphalan, chlorambucil, cyclophosphamide, vindesine, mitomycin, bleomycin, tamoxifen, and taxol, and more preferably cisplatin, paclitaxel, 5-fluorouracil (5-FU), but is not limited thereto in order to achieve the object of showing a synergistic effect on the anticancer effect by co-treating with the nucleic acid molecule of the present invention.

(34) The cancer may be any one selected from the group consisting of colon cancer, breast cancer, uterine cancer, cervical cancer, ovarian cancer, prostate cancer, brain tumor, head and neck carcinoma, melanoma, myeloma, leukemia, lymphoma, gastric cancer, lung cancer, pancreatic cancer, non-small cell lung cancer, liver cancer, esophageal cancer, small intestine cancer, anal cancer, fallopian tube cancer, endometrial cancer, vaginal cancer, vulva cancer, Hodgkin lymphoma, bladder cancer, kidney cancer, ureter cancer, kidney cell carcinoma, kidney pelvic carcinoma, bone cancer, skin cancer, head cancer, cervical cancer, skin melanoma, choroidal melanoma, endocrine gland cancer, thyroid carcinoma, parathyroid gland cancer, adrenal cancer, soft tissue sarcoma, urethral cancer, penile cancer, central nervous system (CNS) tumor, primary CNS lymphoma, spinal cord tumor, polymorphic glioblastoma and pituitary adenoma.

(35) The pharmaceutical composition of the present invention may further include an adjuvant in addition to the single domain antibody. The adjuvant can be used without limitation as long as it is known in the art. However, it can include, for example, Freund's complete or incomplete adjuvants to enhance its effectiveness

(36) The pharmaceutical composition according to the present invention may be produced in the form of incorporation of an active ingredient into a pharmaceutically acceptable carrier. In this regard, the pharmaceutically acceptable carrier includes a carrier, excipient and diluent commonly used in the pharmaceutical field. Pharmaceutically acceptable carriers for use in the pharmaceutical compositions of the present invention include, but are not limited to, lactose, dextrose, sucrose, sorbitol, mannitol, xylitol, erythritol, maltitol, starch, acacia rubber, alginate, gelatin, calcium phosphate, calcium silicate, cellulose, methylcellulose, polyvinylpyrrolidone, water, methyl hydroxybenzoate, propyl hydroxybenzoate, talc, magnesium stearate and mineral oil.

(37) The pharmaceutical composition of the present invention may be formulated in the form of oral preparations such as powder, granule, tablet, capsule, suspension, emulsion, syrup or aerosol, external preparation, suppositories or sterilized injection solutions according to each conventional method.

(38) Formulations can be prepared by using generally used excipients or diluents such as fillers, extenders, binders, wetting agents, disintegrating agents and surfactant. Solid formulations for oral administration include tablets, pills, powders, granules and capsules. These solid formulations are prepared by mixing one or more excipients such as starch, calcium carbonate, sucrose, lactose and gelatin to active ingredients. Except for the simple excipients, lubricants, for example magnesium stearate, and talc can be used. Liquid formulations for oral administrations include suspensions, solutions, emulsions and syrups, and the above-mentioned formulations can contain various excipients such as wetting agents, sweeteners, aromatics and preservatives in addition to generally used simple diluents such as water and liquid paraffin. Formulations for parenteral administration include sterilized aqueous solutions, water-insoluble excipients, suspensions, emulsions, lyophilized preparations and suppositories. Water-insoluble excipients and suspensions can include propylene glycol, polyethylene glycol, vegetable oil like olive oil, injectable ester like ethylolate, etc. Suppositories can include witepsol, tween 61, cacao butter, laurin butter, glycerogelatin, etc.

(39) The pharmaceutical composition according to the present invention may be administered to a subject by various routes. All modes of administration may be expected, for example, by oral, intravenous, intramuscular, subcutaneous, intraperitoneal injection.

(40) The administration amount of the pharmaceutical composition according to the present invention is selected in consideration of the age, weight, sex, physical condition, etc. of the subject. It is apparent that the concentration of the single domain antibody included in the pharmaceutical composition may be variously selected depending on the subject. It is preferably included in the pharmaceutical composition at a concentration of 0.01 μg/ml to 5,000 μg/ml. When the concentration is less than 0.01 μg/ml, the pharmaceutical activity may not be exhibited. When the concentration is more than 5,000 μg/ml, it may be toxic to the human body.

(41) The pharmaceutical composition of the present invention may be used for preventing or treating cancer and complications thereof and can also be used as an anticancer adjuvant.

(42) Further, the present invention provides a method of preventing and treating cancer, in which the method includes administering to a subject the nucleic acid molecule of claim 1 in a pharmaceutically effective amount.

(43) The pharmaceutical composition of the present invention is administered in therapeutically or pharmaceutically effective amounts. The term “pharmaceutically effective amount” means an amount sufficient to treat a disease at a reasonable benefit/risk ratio applicable to medical treatment. The effective dose level may be determined by factors such as the subject's species, severity, age, sex, drug activity, drug sensitivity, the time of administration, the route of administration, the rate of excretion, the duration of the treatment and co-administered drugs, and other factors well known in the medical arts. The present invention is described in more detail with reference to the following Examples. However, the following Examples are only for the purpose of illustrating the present invention, and therefore, the present invention is not limited thereto.

Example 1. Preparation of Double Target siRNA

(44) The double target siRNA (double strand) which is capable of simultaneously inhibiting signal transducer and activator of transcription 3 (STAT3) and mammalian target of rapamycin (mTOR) was prepared by sequences as shown in Table 1 below (Bioneer, Daejeon, Korea).

(45) TABLE-US-00001 TABLE 1  SEQ ID set siRNA Sequence Length NO. 1 antisense_mTOR (5′.fwdarw.3′) gacuguggcau 21 1 ccaccugcau antisense_STAT3 (5′.fwdarw.3′) cugacuccgcg 2 gauggacgua 2 antisense_mTOR (5′.fwdarw.3′) gacuguggcau 20 3 ccaccugca antisense_STAT3 (5′.fwdarw.3′) cugacuccgcg 4 gauggacgu 3 antisense_mTOR (5′.fwdarw.3′) gacuguggcau 19 5 ccaccugc antisense_STAT3 (5′.fwdarw.3′) cugacuccgcg 6 gauggacg 4 antisense_mTOR (5′.fwdarw.3′) gacuguggcau 18 7 ccaccug antisense_STAT3 (5′.fwdarw.3′) cugacuccgcg 8 gauggac 5 antisense_mTOR (5′.fwdarw.3′) caagcugcugu 17 9 ggcuga antisense_STAT3 (5′.fwdarw.3′) guucgacgaca 10 ucgacu 6 antisense_mTOR (5′.fwdarw.3′) ugcugggccgc 20 11 augcgcugc antisense_STAT3 (5′.fwdarw.3′) acgacccggcg 12 ucaccgacg 7 antisense_mTOR (5′.fwdarw.3′) gcugggccgca 19 13 ugcgcugc antisense_STAT3 (5′.fwdarw.3′) cgacccggcgu 14 caccgacg 8 antisense_mTOR (5′.fwdarw.3′) cugggccgcau 18 15 gcgcugc antisense_STAT3 (5′.fwdarw.3′) gacccggcguc 16 accgacg 9 antisense_mTOR (5′.fwdarw.3′) ugggccgcaug 17 17 cgcugc antisense_STAT3 (5′.fwdarw.3′) acccggcguca 18 ccgacg

(46) 17mer of 21mers in siRNA represented by SEQ ID NOS: 1 and 2 of Set 1, 16mer of 20mer in siRNA represented by SEQ ID NOS: 3 and 4 of Set 2, 15mer of 19mer in siRNA represented by SEQ ID NOS: 5 and 6 of Set 3, 14mer of 18mer in siRNA represented by SEQ ID NOS: 7 and 8 of Set 4, and 16mer of 17mer in siRNA represented by SEQ ID NOS: 9 and 10 of Set 5 are complementarily linked. Further, 17mer of 20mer in siRNA represented by SEQ ID NOS: 11 and 12 of Set 6, 16mer of 19mer in siRNA represented by SEQ ID NOS: 13 and 14 of Set 7, 15mer of 18mer in siRNA represented by SEQ ID NOS: 15 and 16 of Set 8, and 14mer of 17mer in siRNA represented by SEQ ID NOS: 17 and 18 of Set 9 are complementarily linked.

(47) Specifically, after two sequences of each set are introduced into cells in the form of a double strand, the siRNA of antisense_mTOR of each set is complementarily linked to the target site of mTOR mRNA (gi|206725550|ref|NM_004958.3| Homo sapiens mechanistic target of rapamycin (serine/threonine kinase) (MTOR), mRNA).

(48) Further, siRNA of antisense_STAT3 of each set is complementarily linked to the target site of STAT mRNA (gi|47080104|ref|NM_139276.2| Homo sapiens signal transducer and activator of transcription 3 (acute-phase response factor) (STAT3), transcript variant 1, mRNA), thereby inhibiting mTOR and STAT3 gene expression.

Example 2. Preparation of Recombinant Expression Vectors Expressing shRNA Including Double Target siRNA

(49) In order to express the double target siRNA represented by SEQ ID NOS: 1 and 2 of Set 1 prepared in Example 1 in cells, nucleic acid molecules encoding shRNAs containing the siRNA double strand sequence and the loop sequence (UUGGAUCCAA loop shRNA and UUCAAGAGAG loop shRNA) were constructed (each nucleic acid molecule sequence is respectively shown in SEQ ID NOS: 20 and 21 of Table 2). Each nucleic acid molecule was placed following the U7 promoter (SEQ ID NO: 19) at the cleavage sites of the restriction enzymes Pst I and Eco RV of the pE3.1 vector (FIG. 1), thereby constructing recombinant expression vectors which are capable of expressing two shRNAs including double target siRNA targeting mTOR and STAT3 in the cells (each shRNA sequence is respectively shown in SEQ ID NOS: 26 and 27).

(50) TABLE-US-00002 TABLE 2  SEQ nucleic acid molecule ID shRNA sequence (5′.fwdarw.3′) NO. UUGGAUCCAA gactgtggcatccacctgcatTTGGATCCAA 20 loop shRNA atgcaggtaggcgcctcagtcTT UUCAAGAGAG gactgtggcatccacctgcatTTCAAGAGAG 21 loop shRNA atgcaggtaggcgcctcagtcTT

Experimental Example 1. Confirmation of mTOR and STAT3 Gene Expression Inhibitory Effect by Double Target siRNA

(51) Hela cells were seeded on a 12-well plate. Then, until the cell confluent reached 50%, the cells were cultured in RPMI medium (Hyclone) supplemented with 10% FBS (Hyclone) at 37° C. and 5% CO2. Then, the cells were transfected with the double target siRNA prepared in Example 1 using lipofectamine 3000 (Invitrogen, Carlsbad, Calif., USA) to perform the know-down of Bcl1, BI1, AR, mTOR and STAT3, simultaneously. After 48 hours of the transfection, the cells were disrupted, and total RNAs were extracted with GeneJET RNA Purification Kit (Invitrogen). The reverse transcription was performed with RevoScript™ RT PreMix (iNtRON BIOTECHNOLOGY) using the extracted total RNA as a template.

(52) 20 μl of a sample containing 25 to 200 ng of the reverse transcribed cDNA, AmpONE taq DNA polymerase (GeneAll) and TaqMan Gene Expression assays (Applied Biosystems) were used. They were reacted with MTOR (Hs00234522_m1), STAT3 (Hs01047580_m1) and GAPDH (Hs02758991_g1) using ABI PRISM 7700 Sequence Detection System and QS3 Real-time PCR (Biosystems). The real-time PCR reaction conditions were [2 minutes at 50° C., 10 minutes at 95° C., and two cycles of 15 seconds at 95° C. and 60 seconds at 60° C.], and the reaction was repeated in total 40 cycles. All reactions were repeated three times, and the mean value of these was obtained. The results were normalized to the mRNA values of the housekeeping gene GAPDH.

(53) As a result, it was confirmed that mTOR and STAT3 had 20% to 40% residual expression compared to the control by double target siRNAs of Sets 1 to 9, and it was found that the double target siRNA simultaneously inhibited expression of both genes (FIG. 2).

Experimental Example 2. Confirmation of Mutual Expression Influence of mTOR and STAT3 Genes

(54) As in Experimental Example 1, human lung cancer cell line A549 was transfected with mTOR siRNA (bioneer, 1058906) (SEQ ID NOs: 22 and 23), STAT3 siRNA (bioneer, 1145658) (SEQ ID NOS: 24 and 25) or both mTOR siRNA and STAT3 siRNA of the following Table 3 using lipofectamine 3000. After 48 hours of the transfection, the rate of decrease in mTOR and STAT3 gene expression was confirmed using Real-time PCR (Taqman) as in Experimental Example 1.

(55) TABLE-US-00003 TABLE 3  SEQ sequence (5′.fwdarw.3′) No. mTOR siRNA sense  GUGGAAACAGGACCCAUGA 22 strand (dTdT) antisense UCAUGGGUCCUGUUUCCAC 23 strand (dTdT) STAT3 siRNA sense  UGUUCUCUGAGACCCAUGA 24 strand (dTdT) antisense UCAUGGGUCUCAGAGAACA 25 strand (dTdT)

(56) TABLE-US-00004 TABLE 4 mTOR std dev STAT3 std dev nc2 1.0000 0.318658 1.0000 0.287738516 simTOR 0.1980 0.076805 1.0705 0.251995803 siSTAT3 1.0507 0.40253 0.6074 0.120361215 simTOR&STAT3 0.3174 0.046248 0.4022 6.7987E−17

(57) As a result, the mTOR and STAT3 expression were decreased by each siRNA. The result was compared with the case of co-treating with both siRNAs, indicating that the mTOR gene and STAT3 expression did not mutually affect (FIG. 3 and Table 4).

Experimental Example 3. Confirmation of Cancer Cell Death by Double Target siRNA

(58) In order to confirm effects on cancer cell death by double target siRNA of Sets 1 to 9 of the present invention, human lung cancer cell line A549 cells were seeded to 5×10.sup.3 cells/well in a 96-well plate, and then the cells were transfected with the double target siRNA (mTOR and STAT3 co-knock down) using lipofectamine 3000. After 48 hours of the transfection and additional 24 hours, the cells were treated with 5 mg/mL MTT (Promega, Ltd.) and incubated for 4 hours. Thereafter, the medium was removed, and the cells were treated with 150 μl of solubilization solution and stop solution and incubated at 37° C. for 4 hours. The absorbance of the reaction solution was measured at 570 nm, and the cell viability was calculated using the following equation.
Cell viability=absorbance of experimental group (570 nm)/absorbance of control group (570 nm)×100(%)  [Equation]

(59) As a result, it was confirmed that when mTOR and STAT3 were simultaneously inhibited by the double target siRNA of the present invention, the cell viability was significantly reduced as compared to the control group. Therefore, it was confirmed that the double target siRNA of Sets 1 to 9 of the present invention effectively led to the cancer cell death (FIG. 4).

Experimental Example 4. Confirmation of Cancer Cell Death by Co-Treatment with Double Target siRNA and Anticancer Agent

(60) 4-1. Co-Treatment with Cisplatin

(61) Human lung cancer cell line A549 cells were seeded at 5×10.sup.3 cells/well in 96-well plates. Then, the cells were transfected with each of the double target siRNAs (mTOR and STAT3 co-knock down) using lipofectamine 3000. After 48 hours of the transfection, the cells were treated with 5 μM of cisplatin and incubated for 10 hours. Thereafter, the MTT reaction was performed as in Experimental Example 3, and the absorbance thereof was measured at 570 nm to calculate the cell viability.

(62) As a result, it was confirmed that when mTOR and STAT3 were simultaneously inhibited by the double-target siRNA of Sets 1 to 9 of the present invention in combination with cisplatin, the cell viability was reduced to about 50% to 70%, and there was a significant difference compared to the control group. Therefore, it was confirmed that when the two genes were simultaneously inhibited even in combination with the anticancer agent, the cell death effect was significantly improved (FIG. 5).

(63) 4-2. Co-Treatment with Paclitaxel

(64) Human lung cancer cell line A549 cells were seeded at 5×10.sup.3 cells/well in 96-well plates. Then, the cells were transfected with each of the double target siRNAs (mTOR and STAT3 co-knock down) using lipofectamine 3000. After 48 hours of the transfection, the cells were treated with 5 μM of paclitaxel and incubated for 10 hours. Thereafter, the MTT reaction was performed as in Experimental Example 3, and the absorbance thereof was measured at 570 nm to calculate the cell viability.

(65) As a result, it was confirmed that when mTOR and STAT3 were simultaneously inhibited by the double-target siRNA of Sets 1 to 9 of the present invention in combination with paclitaxel, the cell viability was reduced to about 30% to 50%, and there was a significant difference compared to the control group. Therefore, it was confirmed that when the two genes were simultaneously inhibited even in combination with the anticancer agent, the cell death effect was significantly improved (FIG. 6).

(66) 4-3. Co-Treatment with 5-Fluorouracil (5-FU)

(67) Human lung cancer cell line A549 cells were seeded at 5×10.sup.3 cells/well in 96-well plates. Then, the cells were transfected with each of the double target siRNAs (mTOR and STAT3 co-knock down) using lipofectamine 3000. After 48 hours of the transfection, the cells were treated with 1 μM of 5-fluorouracil and incubated for 10 hours. Thereafter, the MTT reaction was performed as in Experimental Example 3, and the absorbance thereof was measured at 570 nm to calculate the cell viability.

(68) As a result, it was confirmed that when mTOR and STAT3 were simultaneously inhibited by the double-target siRNA of Sets 1 to 9 of the present invention in combination with 5-fluorouracil, the cell viability was reduced to about 30%, and there was a significant difference compared to the control group. Therefore, it was confirmed that when the two genes were simultaneously inhibited even in combination with the anticancer agent, the cell death effect was significantly improved (FIG. 7).

Experimental Example 5. mTOR and STAT3 Inhibitory Effect of shRNA Including Double Target siRNA

(69) A549 cells were transfected with 0, 1 and 2 μg of the vector containing the TTGGATCCAA loop shRNA sequence represented by SEQ ID NO: 20 or the TTCAAGAGAG loop shRNA represented by SEQ ID NO: 21 prepared in Example 2 using lipofectamine 3000. After 48 hours of the transfection, the decrease level in mTOR and STAT3 gene expression was confirmed using the real time PCR analysis method as described in Experimental Example 1.

(70) As a result, the expression of mTOR and STAT3 was decreased in both shRNAs containing the double target siRNA of the present invention, and the level showed a downward tendency to about 20% in proportion to the DNA amount of shRNA (FIG. 8).