Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

L-asparaginase (EC 3.5.1.1) was purified to homogeneity from Thermus thermophilus. The apparent molecular mass of L-asparaginase was found to be 33 kDa by SDS-PAGE, whereas by Sephacryl S-300 superfine column it was found to be 200 kDa, indicating that the enzyme in the native stage acts as hexamer. It is a thermostable enzyme and keeps all of its activity at 80 degrees C for 10 min. The antiproliferative activity of the purified L-asparaginase from T. thermiphilus was tested against the following human cell lines: K-562 (chronic myelogenous leukemia), Raji (Burkitt's lymphoma), SK-N-MC (primitive neuroectodermal tumor), HeLa (cervical cancer), BT20 and MCF7 (breast cancers), HT-29 (human colon cancer), and OAW-42 (ovarian cancer). The antiproliferative activity of T. thermophilus enzyme was compared with Erwinase, the commercially available L-asparaginase from Erwinia corotovora. The potency difference between the two L-asparaginases was greater in HeLa and SK-N-MC than in other cell lines. The fact that L-asparaginase from T. thermophilus does not hydrolyse L-glutamine makes it advantageous for future clinical trials.
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PMID:Antitumor activity of L-asparaginase from Thermus thermophilus. 1126 87

Serological identification of tumor antigens by cDNA expression cloning is a technique used to isolate cDNAs encoding tumor antigens that are recognized by IgG antibodies in sera from cancer patients. It is also useful for the isolation of tumor antigens recognized by T cells. We applied this method to identify melanoma antigens recognized by the serum from a patient with a good prognosis who had T-cell-infiltrated melanoma and vitiligo. By screening a lambda phage cDNA library constructed from a highly pigmented melanoma cell line, SKmel23, with the patient's serum, 50 positive cDNA clones consisting of 26 distinct antigens were isolated. Of these, 20 encoded known proteins, and 6 encoded previously uncharacterized ones. The most frequently isolated clone, which we named KU-MEL-1, was unknown previously but was homologous to partial cDNA sequences registered in the expressed sequence tag database. Reverse transcription-PCR and Northern blot analysis demonstrated that KU-MEL-1 was strongly expressed in most melanoma cell lines, melanoma tissue samples, and cultured melanocytes and weakly expressed in cell lines derived from other types of tumors, as well as in some normal tissues, including testis. Western blot analysis with polyclonal murine antibody generated by immunization with the recombinant KU-MEL-1 protein demonstrated that the KU-MEL-1 protein was preferentially expressed in melanoma cells and melanocytes. IgG antibodies against KU-MEL-1 were detected in the sera from 9 of 26 melanoma patients and from some patients with other cancers, including brain tumor, esophageal cancer, colon cancer, and chronic myelogenous leukemia, but were not detected in sera from 30 healthy individuals. Although the IgG specific for KU-MEL-1 was not detected in sera from 12 vitiligo patients, it was detected in sera from 7 of 11 patients with Vogt-Koyanagi-Harada disease that is thought to be an autoimmune disease against melanocytes. These results suggest that KU-MEL-1 may be a useful target for the development of diagnostic and therapeutic methods for patients with various cancers, particularly with melanoma, as well as patients with autoimmune diseases against melanocytes.
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PMID:Tumor antigens isolated from a patient with vitiligo and T-cell-infiltrated melanoma. 1218 44

The c-kit tyrosine kinase inhibitor STI571 exhibits a substantial therapeutic activity in patients with chronic myeloid leukemia and gastrointestinal stromal tumors respectively associated with constitutive activation of the BCR-ABL and c-kit tyrosine kinases. Human colorectal tumors also express the c-kit proto-oncogene. The present study focuses on the anticancer activity of STI571 in human colorectal tumor cells in vitro and in vivo. The c-kit receptor was identified as a M(r) 145,000 immunoreactive band in human colon cancer cells HT29, HCT8/S11, and HCT116. Cellular invasion induced by 10 ng/ml stem cell factor (EC(50) = 3 ng/ml) in HT29 cells was blocked by 1 micro M STI571 (IC(50) = 56 nM) and pharmacological inhibitors of several oncogenic signaling pathways, namely, phosphatidylinositol 3-kinase (LY294002), Rho GTPases (Clostridium botulinum exoenzyme C3 transferase), and Rho-kinase (Y27632). STI571 inhibited HT29 cell proliferation (IC(50) = 6 micro M) and induced apoptosis in vitro. These cellular effects were associated with a decrease in tumor growth. We also demonstrated that stem cell factor is a proangiogenic factor in vivo and in vitro. These encouraging results warrant further preclinical investigations and clinical trials on the use of the c-kit inhibitor STI571 as a chemotherapeutic agent in colon cancer prevention and in treatment of advanced colorectal cancers associated with liver metastases.
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PMID:The c-kit tyrosine kinase inhibitor STI571 for colorectal cancer therapy. 1220 34

Between 1990 and 2001, altogether 28 new anticancer drugs were approved for use in Israel. The new agents include cytotoxic drugs, biologic compounds, and hormone therapies. Among the cytotoxic agents introduced, the taxanes, vinorelbine, gemcitabine, irinotecan, topotecan and temozolomide, represent important new drugs active in a range of solid malignancies including lung, breast, ovarian, bladder, pancreatic, and colon cancer as well as brain tumors. Epirubicin, idarubicin, and liposomal doxorubicin offer less toxic and in some instances more effective alternatives to older anthracylines for leukemia, breast cancer, ovarian cancer and other diseases. New oral agents are offering a chance for disease palliation without the need for burdensome intravenous access. Rituximab and trastuzumab have introduced monoclonal antibody therapy to the clinic, substantially improving the treatment of patients with lymphoma and breast cancer, respectively. The first tyrosine kinase inhibitor, a molecularly targeted therapy, imatinib, was approved for use in chronic myeloid leukemia and has also shown remarkable activity in gastrointestinal stromal tumors. A variety of aromatase inhibitors have provided less toxic and more effective hormone therapy for the treatment of breast cancer. The challenge for clinicians is to optimize the use of the new available agents for their patients' benefit, and the challenge for health policy-makers in Israel is to integrate the new anticancer pharmaceuticals into the basic health benefits package mandated for all citizens.
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PMID:New drugs for the treatment of cancer, 1990-2001. 1251 6

Imatinib mesylate is a small molecule inhibitor of the c-Abl, platelet-derived growth factor (PDGF) receptor and c-Kit tyrosine kinases that is approved for the treatment of Philadelphia chromosome-positive chronic myeloid leukemia (CML) and gastrointestinal stromal tumors. Glioblastoma multiforme is a highly malignant primary brain tumor that is usually treated with surgery and/or radiotherapy. Previous studies implicate an autocrine loop caused by high expression of PDGF and its receptor, PDGFR, in the proliferation of some glioblastomas. Here, we demonstrate that pretreatment of a human glioblastoma cell line, RuSi RS1, with imatinib significantly enhanced the cytotoxic effect of ionizing radiation. This effect was not seen in human breast cancer (BT20) and colon cancer (WiDr) cell lines. Whereas c-Abl and c-Kit were expressed about equally in the three cell lines, RuSi RS1 cells showed significantly higher expression of PDGFR-beta protein in comparison to BT20 and WiDr. Imatinib treatment of RuSi RS1 cells decreased overall levels of cellular tyrosine phosphorylation and specifically inhibited phosphorylation of PDGFR-beta, while c-Abl was not prominently activated in these cells. These results suggest that imatinib may have clinical utility as a radiosensitizer in the treatment of human glioblastoma, possibly through disruption of an autocrine PDGF/PDGFR loop.
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PMID:Imatinib mesylate radiosensitizes human glioblastoma cells through inhibition of platelet-derived growth factor receptor. 1572 3

Two major transcripts of lymphoid enhancer factor-1 (LEF-1) have been described. The long isoform with b-catenin binding domain functions as a transcriptional enhancer factor. The short isoform derives from an intronic promoter and exhibits dominant negative activity. Recently, alterations of LEF-1 isoforms distribution have been described in colon cancer. In the current study we employed a quantitative real-time reverse transcription PCR method (TaqMan) to analyze expression of LEF-1 isoforms in a large cohort of human tumor (n = 304) and tumor-free control samples (n = 56). The highest expression level of LEF-1 was found in carcinoma samples whereas brain cancer samples expressed little. Expression of LEF-1 was different in distinct cancer types. For example, the mRNA level of LEF-1 was lower in testicular tumor samples compared with tumor-free control samples. Besides epithelial cancers, significant LEF-1 expression was also found in hematopoietic cells. In hematological malignancies, overall LEF-1 level was higher in lymphocytic leukemias compared with myeloid leukemias and normal hematopoiesis. However, acute myeloid leukemia and acute lymphocytic leukemia showed a significantly increased fraction of the oncogenic LEF-1 compared with chronic lymphocytic leukemia and chronic myeloid leukemia. Taken together, these data suggest that LEF-1 is abundantly expressed in human tumors and the ratio of the oncogenic and the dominant negative short isoform altered not only in carcinomas but also in leukemia.
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PMID:Alterations of lymphoid enhancer factor-1 isoform expression in solid tumors and acute leukemias. 1575 19

This study was conducted to determine the outcome of patients who develop a second neoplasm after radiotherapy (RT) for a childhood solid tumor. From 1956 to 1998, 429 children with a malignant solid tumor were treated at a single radiation oncology facility. The medical records and radiotherapy charts were reviewed to determine if the patient developed a secondary neoplasm after treatment for malignancy. Twenty-three (5.4%) patients developed a secondary neoplasm. There were 12 males and 11 females with a median age at RT of 6.6 years (range, 2 months to 20 years). There were 14 malignant neoplasms in 13 (3.0%) and 14 benign neoplasms in 11 patients (2.6%). The types of initial solid tumors treated with RT were Ewing sarcoma in 6, Wilms tumor in 6, medulloblastoma in 5, neuroblastoma in 3, and other in 3. Median RT dose was 45 Gy (range, 12.3 to 60 Gy) using 4 MV in 9, 1.25 MV in 8, 250 KV in 4, and 6 MV photons in 1 patient. One child was treated using 15-MeV electrons. Fourteen had chemotherapy. Median follow-up was 23.2 years (range, 5.3 to 44.4 years). For the 14 malignant neoplasms, the median time interval from initial tumor to second malignancy was 10.1 years. The 14 second malignant neoplasms (SMN) were osteosarcoma in 3, breast carcinoma in 2, melanoma in 2, malignant fibrous histiocytoma in 1, dermatofibrosarcoma in 1, leiomyosarcoma in 1, mucoepidermoid carcinoma in 1, colon cancer in 1, chronic myelogenous leukemia in 1, and basal cell carcinoma in 1. Ten of the 14 SMN (71%) were at the edge or inside the RT field. The 5- and 10-year overall survival rate after diagnosis of an SMN was 69.2%; it was 70% for children with a SMN at the edge or inside the RT field and 66.7% for those outside of the RT field. The 14 benign neoplasms appeared at a median time of 16.9 years and included cervical intraepithelial neoplasia in 3, osteochondroma in 3, thyroid adenoma in 1, duodenal adenoma in 1, lipoma in 1, cherry angioma in 1, uterine leiomyoma in 1, ovarian cystadenofibroma in 1, and giant cell tumor in 1. Only 5 (36%) of the 14 benign tumors occurred in the RT field, with osteochondroma being the most common. Of 189 deaths occurring in 429 patients, only 3 (1.6%) were secondary to radiation-induced malignancy. Not all SMN in children receiving RT occur in the irradiated field. More than two-thirds of children with a radiation-induced malignancy are alive 10 years after the diagnosis of a SMN.
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PMID:Secondary neoplasms after radiotherapy for a childhood solid tumor. 1580 94

The PARK2 gene, previously identified as a mutated target in patients with autosomal recessive juvenile parkinsonism (ARJP), has recently been found to be a candidate tumor suppressor gene in ovarian, breast, lung and hepatocellular carcinoma that maps to the third common fragile site (CFS) FRA6E. PARK2 is linked to a novel described PACRG gene by a bidirectional promoter containing a defined CpG island in its common promoter region. We have studied the role of promoter hypermethylation in the regulation of PARK2 and PACRG expression in different tumor cell lines and primary patient samples. Abnormal methylation of the common promoter of PARK2 and PACRG was observed in 26% of patients with acute lymphoblastic leukemia and 20% of patients with chronic myelogenous leukemia (CML) in lymphoid blast crisis, but not in ovarian, breast, lung, neuroblastoma, astrocytoma or colon cancer cells. Abnormal methylation resulted in downregulation of PARK2 and PACRG gene expression, while demethylation of ALL cells resulted in demethylation of the promoter and upregulation of PARK2 and PACRG expression. By FISH, we demonstrated that a lack of PARK2 and PACRG expression was due to biallelic hypermethylation and not to deletion of either PARK2 or PACRG in ALL. In conclusion, our results demonstrate for the first time that the candidate tumor suppressor genes PARK2 and PACRG are epigenetically regulated in human leukemia, suggesting that abnormal methylation and regulation of PARK2 and PACRG may play a role in the pathogenesis and development of this hematological neoplasm.
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PMID:Abnormal methylation of the common PARK2 and PACRG promoter is associated with downregulation of gene expression in acute lymphoblastic leukemia and chronic myeloid leukemia. 1628 63

Why does it seem that, repeatedly, when a new treatment with a striking effect is discovered in the cancer field, it is effective for a very rare cancer type? For example, groundbreaking therapeutic discoveries have been made for extremely uncommon malignancies such as hairy cell leukemia, chronic myelogenous leukemia, seminoma, gastrointestinal stromal tumor, (del)5q myelodysplastic syndrome, and acute promyelocytic leukemia. In contrast, progress in the most common and most intensively studied tumors - lung, breast, prostate, and colon cancer - has been slow and incremental. We hypothesize that the reason for this phenomenon is that the pathophysiologic basis for a tumor being rare is one and the same as the reason that it may ultimately be so treatable. That is, if a cancer can be derived only via a single aberrant molecular genetic aberration, then it should be both rare and easily targeted by a molecular cancer therapeutic approach. If, on the other hand, many distinct pathways can lead to the development of a specific tumor type, it should occur much more commonly and be significantly more difficult to treat. The corollary to our hypothesis is the prediction that new therapies will continue to show their most salutary effects in rare cancers. Furthermore, only by stratifying the common tumors, especially when using targeted agents, into the molecular subsets of diseases that compose them are we likely to achieve a substantial effect in these disorders.
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PMID:Uncommon tumors and exceptional therapies: paradox or paradigm? 1743 Nov

A biomarker is defined as "a characteristic that is objectively measured and evaluated as an indicator of normal biologic processes, pathogenic processes, or pharmacologic/pharmacodynamic responses to a therapeutic intervention". Various assays, including immunohistochemistry, gene constitution such as amplification, mutation, and rearrangement, gene and protein expression analysis such as single gene or protein expression, exhaustive analysis and gene or protein signature and single nucleotide polymorphism have been used to identify biomarkers in recent years. No therapeutic effects have yet been predicted based on the results of such exhaustive gene analysis because of low reproducibility although some correlate with the prognosis of patients. Biomarkers such as HER2 for breast cancer or EGFR mutation for lung cancer and KRAS mutation in colon cancer have contributed to identify a patient population that might show a good and bad treatment response, respectively. On the other hand, other biomarkers such as bcr-abl, c-kit gene mutation and CD20 expression, which are positive for CML, GIST and B cell lymphoma, respectively, have crucial biological significance but have not necessarily been used for practical clinical screening since pathological diagnosis coincide with finding of biomarkers. Hence, much work remains to be done in many areas of biomarker research.
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PMID:Critical comments for roles of biomarkers in the diagnosis and treatment of cancer. 2165 49


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