Clinical and biologic correlates of insulin binding by leukemia lymphoblasts

Acute lymphoblastic leukemia in children. Advances and prospectus

During the past decade, advances in the treatment of childhood acute lymphoblastic leukemia (ALL) have continued, largely due to improved disease-free survival of poor-prognosis subgroups, improved sanctuary therapy, shortening of therapy duration, and salvage of relapsed patients with better chemotherapy regimens and with bone marrow transplantation. Nonetheless, more children continue to die of ALL than of any other childhood cancer. This review outlines central issues in the staging and treatment of ALL that should be addressed if the cure rate in childhood ALL is to be significantly improved. Present dilemmas in the staging of ALL include the following: lack of standardization of staging systems; complicated algorithms; variable application and interpretation of multivariate analyses; dynamic interactions between prognostic front end variables and subsequent treatment; ambiguity of prognostic factors that are predictive of outcome but biologically inexplicable; unsuccessful attempts to define a good-prognosis subgroup for the purpose of streamlining therapy to a minimum; and the interface between ALL and non-Hodgkin's lymphoma and myeloid leukemias. The remaining therapeutic problems include a lack of reliable in vitro tests of chemosensitivity and chemoresistance, inability to quantitate residual leukemia after remission induction or to detect drug-resistant clones of cells before they are clinically manifest, and delivery of optimum therapy and supportive care to all children with ALL.

Growth of IM-9 human lymphoblasts in serum-free medium: stimulation by glucocorticoids

The IM-9 human B-lymphoblast cell line grows well in a completely defined serum-free medium containing insulin, transferrin, low density lipoprotein and oleic acid in complex with fatty acid-free bovine serum albumin. Growth of the IM-9 cells is stimulated by addition of physiological concentrations of hydrocortisone to this medium. The order of growth stimulatory potency of several steroids is dexamethasone greater than hydrocortisone greater than aldosterone, whereas testosterone does not stimulate growth of the IM-9 cells. This order of potency suggests that the effect is mediated by binding to glucocorticoid receptors. Growth of the IM-9 cells is also stimulated by the neuropeptide substance P. The defined serum-free medium described in this report will be useful for further studies of the biological responses of the IM-9 cells to other hormones in the absence of interference from hormones and growth factors present in serum.

Differentiation-linked leukemogenesis in lymphocytes

Most human lymphoid malignancies preserve a pattern of gene expression reflecting their proliferative activity and the development level of clonal expansion and maturation arrest. Characteristics of leukemia and other cancer cells frequently considered to reflect aberrant differentiation may more often reflect clonal selection of cell types that are normally infrequent and transitory. The differentiation status of progenitor or mature lymphoid cells influences which genetic elements are at risk of being exploited, via mutation, recombination, or deletion, for clonal advantage. These alterations may frequently arise spontaneously as a consequence of the unique developmental and functional programs of lymphoid cells and have as a major phenotypic consequence the stabilization of transitory cellular phenotypes.

Human leukemic cells: receptor binding and biological effects of insulin and insulin-like growth factors

Receptor binding and biological effects of insulin and insulin-like growth factors I and II (IGF I/II) were assessed in three human malignant cell lines: a Burkitt-type ALL-cell line, a ANLL-cell line and a Hodgkin's disease-cell line. Insulin receptor binding could be demonstrated in Burkitt-type ALL cells and ANLL cells, whereas no insulin receptor binding was detectable in Hodgkin cells. IGF I and IGF II binding could be demonstrated in all leukemic cells. Insulin stimulated glycogen synthesis in the insulin receptor bearing cell lines. DNA synthesis was stimulated by insulin, IGF I and II. IGF I was more active in stimulating DNA synthesis than IGF II.