Changes in Activities of Enzymes Related to Energy Metabolism in Canine Lymphoma Cells

Abstract

ABSTRACT. Alterations in the activities of enzymes related to energy metabolism in canine lymphoma cells were investigated. Cytosolic pyruvate kinase (PK) and mitochondrial malate dehydrogenase (MDH) activities in lymphoma cells were significantly higher than those in lymphocytes obtained from lymph nodes of healthy dogs, whereas cytosolic lactate dehydrogenase (LDH) activity was significantly lower in lymphoma cells. The cytosolic M/L ratio (MDH activity/LDH activity), which is considered to be a good indicator of energy metabolism related to glucose utilization in animal tissues, was significantly higher in lymphoma cells than in the normal lymphocytes. KEY WORDS: canine, lymphoma, malate dehydrogenase.J. Vet. Med. Sci. 67(6): 615-616, 2005 Lymphoma is one of the most common neoplasms observed in the dog and primarily affects middle-aged to older dogs [14]. The most common form of canine lymphoma is the multicentric form, which usually presents with superficial lymphadenopathy. Morphology, immunophenotypes, responsiveness to chemotherapy, and correlations between morphology and survival time of canine lymphoma have been reported [8,9,17]. Several reports have discussed the metabolic alterations of dogs with lymphoma [15,16,20], however, the enzyme activities of lymphoma cells per se have not been investigated. In the present study, lymphoma cells and normal lymphocytes from the lymph nodes of healthy dogs were obtained, and the activities of the enzymes related to energy metabolism including hexokinase (HK), piruvate kinase (PK), lactate dehydrogenase (LDH), malate dehydrogenase (MDH) and aspartate aminotransferase (AST) were measured.Five healthy mixed breed dogs (2 males and 3 females; 3-6 years old) maintained for research in our laboratory and fed on a commercial diet (Hill's Pet Products, Topeka, KS, U.S.A.) were used as control dogs. Their hematological and serum chemistry values were within the normal ranges. In addition, ten dogs referred to our Veterinary Medical Teaching Hospital and diagnosed as multicentric, stage III lymphoma were used. Signalment of the ten dogs are shown in Table 1.Popliteal lymph nodes of normal dogs were obtained surgically under general anesthesia with isoflurane (Rhodia, England). Lymphoma cells were collected by fine needle aspiration biopsy from enlarged lymph nodes of the dogs with lymphoma before the initiation of chemotherapy and put in RPMI 1640 medium. Lymphocytes and lymphoma cells were further purified by gradient centrifugation with a commercially available mononuclear cell isolating solution (Histopaque-1077, Sigma-Aldrich Co., St. Louis, MO, U.S.A.), followed by three washes with cold phosphatebuffered saline (0.15 M NaCl, pH 7.2).Washed lympyocytes were resuspended in 2 ml ice-cold STE solution (0.25 M sucrose, 10 mM Tris-Hcl buffer, pH 7.5, containing 2 mM EGTA), followed by homogenization with an ultrasonic processor (VP-5, Taitek, Koshigaya, Japan) for 5 sec. The homogenate was centrifuged at 100 × g for 1 min to remove nuclei and cell debris, and the supe...

Reference intervals for the activity of lactate dehydrogenase and its isoenzymes in the serum and cerebrospinal fluid of healthy canines

“…In general, LD‐4 and LD‐5 predominate in skeletal muscle and hepatic tissues, LD‐1 and LD‐2 predominate in aerobic tissues such as the heart . Washizu et al and others have demonstrated that there are species‐specific LD isoenzyme patterns in various cell and tissue types, indicating that species differences in nutrient metabolism may play an important role in the generation of LD isoenzyme patterns …”

“…15,42 Washizu et al and others have demonstrated that there are species-specific LD isoenzyme patterns in various cell and tissue types, indicating that species differences in nutrient metabolism may play an important role in the generation of LD isoenzyme patterns. 15,[43][44][45] Given these differences, some of the specific isoenzyme patterns described in human disease states may not be transferrable to veterinary medicine and warrant further investigation in veterinary patients.…”

HORMONE-DEPENDENT AND HORMONE-INDEPENDENT CONTROL OF METABOLIC AND DE­VEL­OP­MEN­TAL FUNCTIONS OF MALATE DEHYDROGENASE – Review

“…It is becoming well established (more evident) that alterations in the activities of enzymes related to energy metabolism (WASHIZU et al, 2005) in malignant cells or cells undergoing the process of transformation are due to alterations in the regulation of mitochondrial and cytosolic MDHs, cytosolic lactate dehydrogenase (LDH) and often also pyruvate kinase (PK). In many cases this process leading to changes in energy metabolism is started by misregulation of one or few genes coding for enzymes participating in TCA or closely related metabolic cycle (RAO et al, 1997;ARAI et al, 2002a,b).…”

NOD/SCID mouse model of canine T‐cell lymphoma with humoral hypercalcaemia of malignancy: cytokine gene expression profiling and in vivo bioluminescent imaging

“…In the absence of chemotherapy, survival beyond 1 month after diagnosis of lymphoma is uncommon 4 . The most common anatomic presentation of canine lymphoma is the multicentric form, which usually presents as superficial lymphadenopathy 5 with or without hepatosplenomegaly. About 26–38% of the lymphomas in dogs 6,7 and 15% of the lymphomas in humans 8 are T cell in origin.…”