TECHNICAL FIELD

This invention relates to treatment of cancers with agents that include a polypeptide.

BACKGROUND

Lung cancer, the leading cause of cancer-related death worldwide, will account for an estimated 157,000 deaths in the United States this year. Approximately 85 to 90% of all cases of lung cancer are non-small-cell lung cancer (NSCLC). There are three main forms of NSCLC, which are classified according to histological subtype: adenocarcinoma (accounting for 40% of lung cancers), squamous cell carcinoma (25%) and large-cell carcinomas (10%). Advanced-stage NSCLC is currently considered an incurable disease for which standard chemotherapy provides marginal improvement in overall survival at the expense of substantial morbidity and mortality. Furthermore, fewer than 30% of patients with metastatic NSCLC have a response to platinum-based chemotherapy, the most commonly used initial treatment in this stage of the disease. Although newer chemotherapeutic agents, such as bevacizumab, have been introduced, the median overall survival of patients with metastatic NSCLC remains approximately 1 year (Sandler et al., 2006, N. Engl. J. Med., 355:2542; Schiller et al., 2002, N. Engl. J. Med., 346:92), and only 3 to 4% of patients with metastatic NSCLC survive 5 years after diagnosis.

SUMMARY

This disclosure is based, in part, on the surprising discovery that, although previously believed to be active intracellularly (see, e.g., Tambe et al., Tambe et al. 2007, Carcinogenesis 28(4):777-784, especiallyFIG. 4B, which suggests that SRPX is localized to the endoplasmic reticulum), a secreted form of the Sushi-Repeat-containing Protein, X-linked (SRPX) protein induces senescence and/or apoptosis in cancer cells. Described herein are methods of diagnosing and treating tumors (e.g., cancers), inducing cellular apoptosis, inducing cellular senescence, and inhibiting cellular proliferation using SRPX agents, e.g., agents comprising SRPX polypeptides delivered to the extracellular surface of tumor cells, or comprising cells (e.g., autologous cells) expressing and secreting exogenous SRPX polypeptides and implanted into or near the tumor.

In one aspect, this application features methods of treating a tumor in a subject by identifying a subject having, at risk for, or suspected of having a tumor; and administering to the extracellular surface of tumor cells in the subject an effective amount of an SRPX agent, e.g., polypeptide or active fragment thereof, thereby treating the tumor. In some embodiments, the tumor is a cancer (e.g., a lung cancer (e.g., a non-small cell lung carcinoma, small-cell carcinoma, adenocarcinoma, or squamous cell carcinoma), a melanoma, carcinoma, breast cancer, ovarian cancer, pancreatic cancer, colorectal carcinoma, or papillary thyroid carcinoma). In some embodiments, the tumor comprises cells in which expression of SRPX is significantly reduced, e.g., undetectable, as compared to wild-type (normal) cells of the same tissue. In some embodiments, the methods include identifying a subject as having a tumor in which expression of SRPX is significantly reduced, e.g., by detecting expression of SRPX in a sample comprising cells from the tumor.

In another aspect, this application features methods of inducing senescence in a cell (e.g., a tumor cell or cancer cell) that include administering to the extracellular surface of the cell an effective amount of a SRPX agent, e.g., polypeptide or active fragment thereof. In some embodiments, the cell is a tumor cell.

In a further aspect, this application features methods of inducing apoptosis in a cell (e.g., a tumor cell or cancer cell) that include administering to the extracellular surface of the cell an effective amount of a SRPX agent, e.g., polypeptide or active fragment thereof.

In another aspect, this application features methods of inhibiting proliferation of a cell (e.g., a tumor cell or cancer cell) that include administering to the extracellular surface of the cell an effective amount of a SRPX agent, e.g., polypeptide or active fragment thereof.

In a further aspect, this application features methods of inhibiting growth (e.g., metastatic growth) in a subject of a tumor that include administering to the extracellular surface of cells of the tumor in the subject an effective amount of a SRPX agent, e.g., polypeptide or active fragment thereof.

In some embodiments, expression of SRPX is significantly reduced, e.g., undetectable, in the cell as compared to a wild-type (normal) cell of the same type/tissue type. In some embodiments, the methods include identifying a cell in which expression of SRPX is significantly reduced, e.g., by detecting expression of SRPX in a sample comprising cells from a tumor.

In another aspect, this application features the use of a SRPX agent in the preparation of a medicament for the treatment of a tumor or cancer (e.g., a lung cancer (e.g., a non-small cell lung carcinoma, small-cell carcinoma, adenocarcinoma, or squamous cell carcinoma), a melanoma, carcinoma, breast cancer, ovarian cancer, pancreatic cancer, colorectal carcinoma, or papillary thyroid carcinoma) in a subject. Compositions comprising a SRPX polypeptide or active fragment thereof are suitable for administration to the extracellular surface of cells in the tumor. In some embodiments, the tumor or cancer is metastatic.

In a further aspect, this application features an isolated SRPX agent for treating a tumor or cancer (e.g., a lung cancer (e.g., a non-small cell lung carcinoma, small-cell carcinoma, adenocarcinoma, or squamous cell carcinoma), a melanoma, carcinoma, breast cancer, ovarian cancer, pancreatic cancer, colorectal carcinoma, or papillary thyroid carcinoma) in a subject. Compositions comprising a SRPX polypeptide or active fragment thereof are suitable for administration to the extracellular surface of cells in the tumor. In some embodiments, the tumor or cancer is metastatic.

In some embodiments, the tumor comprises cells in which expression of SRPX is significantly reduced, e.g., undetectable, as compared to wild-type (normal) cells of the same tissue. In some embodiments, the methods include identifying a subject as having a tumor in which expression of SRPX is significantly reduced, e.g., by detecting expression of SRPX in a sample comprising cells from the tumor.

In some embodiments, the SRPX agent is a composition that includes a polypeptide having a sequence at least 80% identical (e.g., at least 85%, 90%, 95%, 98%, or 99% identical) to SEQ ID NO:1 or SEQ ID NO:2, or an active fragment of either. The polypeptide can be conjugated to a heterologous moiety (e.g., a heterologous polypeptide sequence). In some embodiments, the SRPX agent includes a functional fragment or domain of SEQ ID NO:1 or SEQ ID NO:2, or a fragment of either. The SRPX agent can be administered, e.g., topically, systemically, or locally (e.g., by a drug-releasing implant). The SRPX polypeptide is administered to the extracellular surface of cells in the tumor.

In some embodiments, the SRPX agent is administered by introducing into the subject a composition that induces the expression of SRPX or an active fragment or analog thereof, e.g., a nucleic acid encoding a polypeptide that includes a sequence at least 80% identical (e.g., at least 85%, 90%, 95%, 98%, or 99% identical) to SEQ ID NO:1 or SEQ ID NO:2, or a fragment of either. The nucleic acid can be in a vector, e.g., a viral vector (e.g., an adenovirus vector, an adeno-associated virus vector, a retrovirus vector, or a lentivirus vector). In some embodiments, the SRPX agent is administered by introducing into the subject a cell that includes a nucleic acid encoding a polypeptide that includes a sequence at least 80% identical (e.g., at least 85%, 90%, 95%, 98%, or 99% identical) to SEQ ID NO:1 or SEQ ID NO:2, or a fragment of either, and wherein the cell secretes the polypeptide.

In another aspect, the invention features methods for treating a tumor in a subject. The methods include identifying a subject having, at risk for, or suspected of having a tumor; and administering to the subject an effective amount of a population of cells expressing a nucleic acid encoding a polypeptide that is at least 95% identical to SEQ ID NO:1, wherein the cells are administered into or near the tumor, thereby treating the tumor.

An active or functional fragment is a portion of the SRPX protein that retains the ability to induce cancer cell senescence and/or apoptosis, e.g., is able to induce cancer cell death or senescence (e.g., lung cancer cell death or senescence) in a relevant assay known in the art, e.g., an assay described herein.

“Polypeptide” and “protein” are used interchangeably and mean any peptide-linked chain of amino acids, regardless of length or post-translational modification.

As used herein, a subject “at risk of developing cancer” is a subject that has a predisposition to develop cancer, i.e., a genetic or familial predisposition to develop cancer or has been exposed to conditions that can result in cancer. From the above it will be clear that subjects “at risk of developing cancer” are not all subjects.

A subject “suspected of having cancer” is one having one or more symptoms of cancer. Symptoms of cancer are well-known to those of skill in the art and include, without limitation, weight loss, weakness, excessive fatigue, difficulty eating, loss of appetite, unusual mole features, newly pigmented skin area, skin growths, skin ulcers, skin lumps, chronic cough, worsening breathlessness, breathing difficulty, enlarged lymph nodes, coughing up blood, blood in the urine, blood in stool, nausea, vomiting, liver metastases, lung metastases, bone metastases, breast or nipple changes, nipple discharge, abdominal fullness, bloating, fluid in peritoneal cavity, constipation, abdominal distension, perforation of colon, acute peritonitis (infection, fever, pain), vaginal bleeding, pain, vomiting blood, heavy sweating, fever, high blood pressure, anemia, diarrhea, jaundice, dizziness, chills, muscle spasms, colon metastases, lung metastases, bladder metastases, liver metastases, bone metastases, kidney metastases, pancreas metastases, difficulty swallowing, and the like. For example, a patient who has been diagnosed by a physician as having cancer is still suspected of having cancer.

The term “cancer” refers to cells having the capacity for autonomous growth. Examples of such cells include cells having an abnormal state or condition characterized by rapidly proliferating cell growth. The term is meant to include cancerous growths, e.g., tumors; oncogenic processes, metastatic tissues, and malignantly transformed cells, tissues, or organs, irrespective of histopathologic type or stage of invasiveness. Also included are malignancies of the various organ systems, such as respiratory, cardiovascular, renal, reproductive, hematological, neurological, hepatic, gastrointestinal, and endocrine systems; as well as adenocarcinomas which include malignancies such as most colon cancers, renal-cell carcinoma, prostate cancer and/or testicular tumors, non-small cell carcinoma of the lung, cancer of the small intestine, and cancer of the esophagus. Cancer that is “naturally arising” includes any cancer that is not experimentally induced by implantation of cancer cells into a subject, and includes, for example, spontaneously arising cancer, cancer caused by exposure of a patient to a carcinogen(s), cancer resulting from insertion of a transgenic oncogene or knockout of a tumor suppressor gene, and cancer caused by infections, e.g., viral infections. The term “carcinoma” is art recognized and refers to malignancies of epithelial or endocrine tissues. In some embodiments, the present methods can be used to treat a subject having an epithelial cancer, e.g., a solid tumor of epithelial origin, e.g., lung, breast, ovarian, prostate, renal, pancreatic, or colon cancer.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

