Invented by Le Sun, Ginette Serrero, Joe Corvera, Yudong Hu, A&G Pharmaceutical Inc
The A&G Pharmaceutical Inc invention works as followsNovel monoclonal antibody and binding fragments of them specific to breast cancer in humans, lung cancer, and colon cancer. Monoclonal antibodies do not bind the normal cell surfaces of human tissues. A cancer-specific antibody with an apparent molecular weight of approximately 150 kD, polynucleotides that encode the antigen as well as the CDR region of the antibodies are also disclosed. These antibodies are tumor-specific and can be used for imaging, detection, diagnosis, therapy and monitoring. Cancer-specific antigens that are recognized by antibodies can be used as targets to detect, diagnose, inhibit or kill cancer cells.
Background for Monoclonal Antibody 7H11 Reactive with Human Cancer
Antibodies as magic bullets” Paul Ehrlich proposed the idea of delivering toxins to cancerous cells over a hundred years ago. Since then, targeted immunotherapy has attracted the interest of many researchers. In 1975, the technology to produce monoclonal antibody (MoAbs) was developed (G. Kohler & C. Milstein 1975, Nature 256:495-497; see also Herzenberg & Milstein Handbook of Exerimental Immunology ed. Weir, Blackwell Scientific, London, 1979, pp. It seemed as if a successful antibody therapy would be imminent (see 25.1?25.7). Early trials revealed that monoclonal antibody therapy was not without its obstacles. Initial clinical experience revealed immune rejection of murine polyclonal antibody and low efficacy (Kwak, et. al. 1995, Clinical Applications of Monoclonal Antibodies, in: Biologic Treatment of Cancer, Eds. V. T. DeVita, Jr., S. Hellman, and S. A. Rosenberg, J. B. Lippincott Co. Philadelphia, Pa. 553?565).
Ideally, an antibody for cancer treatment should have a strong affinity for its antigen and a good unconjugated antibodies should work in synergy with the immune system effector mechanism of the host. The use of therapeutic antibodies to induce anti-cancer mechanisms, such as ADCC (antibody-dependent cell cytotoxicity) and complement-dependent lympholysis (Waldman, et. al., Ann. Oncol, 5 Suppl. Oncol, 5 Suppl.
Nearly every monoclonal antibody that recognizes antigens in human cancer cells also binds to normal human cells expressing those same antigens (Jurcic et. al., 1996. Cancer Chemotherapy & Biological Response Modifiers, Annual, Eds. Pinedo et al. pp. 168?188). Cross-reactivity can compromise therapeutic efficacy and cause toxicity. This has led to a continued interest in the definition of antigenic targets unique to tumor cells. The preparation of cancer-specific antibodies and the development of cancer-specific antigens is highly desirable. Identification of cancer antigens allows for the development of selective immunotherapy against neoplastic disease. It is possible to use a determinant expressed exclusively by tumor cells or cancer cells but not in normal tissues and cells. This allows for the elimination of neoplastic tissue and cells while protecting the viability of normal cells. Colcher et. al., 1981. Proc. Natl. Acad. Sci. 78:3199?3203.
The process of discovering unique antigens for cancer is long, tedious, and complex. It involves a thorough weeding-out of antigens that are expressed both on cancer cells or tumor tissues and normal tissue (see, e.g. U.S. Pat. Nos. Nos. Malignant cells are similar to their normal counterparts. Cancer cells are often ‘low-visible’. The majority of cancer antigens, which are also expressed in normal cells, are autoantigens and self-antigens. “Often, the cancer-associated antigen is identical with the normal antigen, but it’s expressed at higher levels. It may also have a small mutation that is not enough to distinguish it from the self antigen.
Despite the obstacles mentioned above, the present invention provides novel and specific monoclonal antibody which are immunoreactive to a cancer-specific surface antigen, and which can be useful in immunotherapy and diagnostic, imaging and monitoring methodologies.
The monoclonal antigen 7H11 is used to diagnose, treat, and prognosis cancers, including lung and breast cancers. The antibody reacts only with tumor cells of human cancer cells, but not with normal tissues.
The invention relates generally to a monoclonal antigen, or binding fragment thereof, that binds to an antigen found in breast cancers, colon cancers, esophage cancers, liver cancers, lung cancers, and ovary tumors. The antigen (i) is a polypeptide with a molecular mass of approximately 150 kDa, as determined by SDS PAGE under reducing condition; (ii), absent from breast, colon, liver, esophagus and lung tissue cells.
Preferably the monoclonal antibodies, or binding fragments thereof, of the invention are produced by a hybridoma cellular line designated 7H11?” The American Type Culture Collection (ATCC), under the Budapest Treaty, has received the Patent Deposit Designation PTA 7443.
The monoclonal antibodies or binding fragments thereof may be Fab fragments (F(ab), F(ab), Fab? fragments, F(ab? F(ab? Fragments or Fv fragments. “It may also be anti-idiotypic antibodies.
Preferably the antibody of the present invention may be marked with a detectable moieties, such as a fluorescent moiety, a radionuclide or a chemiluminescent, bioluminescent, or a bioluminescent agents.
The hybridoma line according to the present invention is 7H11 cell line. The hybridoma line of the invention is 7H11 in a preferred embodiment.
The present invention also provides an antigen-recognized antigen that is present in breast cancers, colon cancers, esophage cancers, lung cancers, liver cancers, and ovarian cancers. This antigen (i) is a polypeptide with a molecular mass of approximately 150 kDa, as determined by SDS PAGE under reducing condition; and (ii), absent from breast, colons, esophagus and liver tissue cells. This antigen can be recognized by a monoclonal antibodies produced by 7H11 hybridoma cells (ATCC).
In a further embodiment of the invention, a method for inhibiting or killing tumour cells is provided. This comprises: providing a monoclonal anti-body, or binding fragment of it, to a patient who needs the treatment, in conditions and amounts sufficient to allow the binding of the antibody to the tumor cells. The immune cells of the patients then kill or inhibit the cancerous cells. The method is preferably used to treat breast cancer or colon cancer. It can also be used for esophagus, liver, lung, and ovary cancer. The monoclonal antibodies are preferably conjugated to a cytotoxic agent such as a photoactivated toxins, radioactive agents, a chemotherapeutic, or a photoactivated agent. The cytotoxic moiety is preferably a Ricin A-chain.
Also, provided is a monoclonal antigen of the invention or its binding fragment that is bound to solid matrix.
The present invention also provides a method of localizing cancer cells within a patient. This includes: (a), administering to the patients a detectably labeled monoclonal antigen or binding fragment of the invention; (b), allowing the detectably labeled (e.g. Radiolabeled, flurochrome-labeled, or enzyme-labeled monoclonal antibodies, or binding fractions thereof, bind to cancer cells in the patient. A method for detecting cancer in a person is also provided. This comprises determining the amount of antigen present in a sample or tissue section taken from the patient. The quantity of antigen can then be correlated with the extent and presence of the cancer. In a preferred embodiment of the method, the antigen can be detected by adding monoclonal antibodies 7H11, goat anti-mouse IgG conjugated with peroxidase, fixing with diaminobenzidene peroxide and examining the section or sample. A reddish brown colour indicates that cells contain the antigen. The method allows for monitoring the effectiveness a cancer therapy by measuring the changes in antigen levels in body fluid samples taken from patients undergoing treatment and correlating these changes with the efficacy of the therapy.
The present invention also relates to another embodiment of a method for diagnosing cancer in a person, which comprises: (a), measuring the levels in cells or tissues or body liquids of a patient; (b), comparing these measured levels with levels in cells or tissues or body fluids in a control human, wherein a rise in the measured antigen levels in the patient in comparison with the control human is associated with cancer. A method for imaging cancer in a person is also provided, which includes administering the antibody to the patient. The antibody can be detected by paramagnetic or radioisotope ions.
The present invention also provides a pharmaceutical formulation containing the monoclonal antibodies, or binding fragments thereof, according the invention, as well as a pharmaceutically accepted carrier, excipient or diluent.
Still, further provided is a method of downregulating HER2 levels on an SKBR-3 cell by contacting it with a monoclonal antigen of the invention. Also, a technique for sensitizing cancer cells to cisplatin and doxorubicin can be achieved by contacting a monoclonal antigen of the invention on the tumor cell. The antibody binds specifically to the extracellular region of a HER2 on the cell.
The present invention also relates to polynucleotides encoding antigens of the invention and polynucleotides encoding monoclonal antibodies of the invention.
The detailed description and examples in the following paragraphs will reveal other aspects of the invention to those who are skilled in the field.
The present invention provides monoclonal antibody fragments and antibodies that recognize and bind a cell surface protein expressed by different human cancer or tumor cells. Surface antigens are only present or highly expressed on cancer cells. They are absent or are less expressed or displayed on cells that are developmentally related and serve as controls. “The newly discovered cancer-specific antigens are targets for therapeutic interventions in cancers, as well for diagnostic and cell purity purposes.Click here to view the patent on Google Patents.