Reiko Tsuyuoka

IL-1 production as a regulator of G-CSF and IL-6 production in CSF-producing cell lines.

We previously demonstrated that colony stimulating factor (CSF)-producing cell lines co-produce interleukin-1 (IL-1) and IL-6 in addition to CSFs. In the present study, we examined the role of IL-1 production in three human tumour cell lines producing granulocyte (G)-CSF, IL-1 and IL-6. Addition of anti-human IL-1 alpha antiserum to the culture caused a 90-62% reduction of G-CSF and a 85-44% reduction of IL-6 production, respectively, as evaluated by enzyme immunoassay in all three cell lines. The decrease of G-CSF and IL-6 production by the anti-IL-1 alpha antiserum was also confirmed at the level of mRNA expression. The anti-IL-1 alpha antiserum did not affect the growth of these cell lines. Excess recombinant IL-1 alpha exogenously added to the culture enhanced G-CSF and IL-6 production in all three cell lines. However, IL-1 alpha had little effect on the growth of these three cell lines. Neither anti-IL-6 nor anti-G-CSF antibodies affected the production of the other cytokines. These results indicate that IL-1 alpha regulates G-CSF and IL-6 production in these tumour cell lines, and suggest that the IL-1 production plays an important role in CSF-producing tumours.

Colony-stimulating factor-producing tumours: production of granulocyte colony-stimulating factor and interleukin-6 is secondary to interleukin-1 production.

We have reported that tumours producing colony-stimulating factor (CSF) also secrete interleukin-1 (IL-1) and IL-6. In the present study, we characterised the role played by IL-1 in CSF production. IL-1 receptor antagonist inhibited the production of granulocyte (G)-CSF and IL-6 by approximately 90% in CSF-producing human lung carcinoma cell lines. Similar results were obtained with hydrocortisone, which suppresses IL-1 gene expression. In contrast, 15 non-CSF-producing human lung carcinoma cell lines did not show detectable IL-1 production, although seven of them were induced to produce G-CSF and IL-6 by exogenous IL-1 alpha. Cell lines that responded to IL-1 alpha, including the CSF-producing lines, expressed receptors for IL-1 alpha. These results indicate that CSF-producing tumours can be characterised by their constitutive IL-1 production, IL-1 receptor expression and IL-1-dependent excess production of G-CSF and IL-6. Furthermore, transcription factor(s) may be involved in the abnormal IL-1 alpha production.

Megakaryocyte potentiating activity of IL‐1, IL‐6 and GM‐CSF as evaluated by their action on in vitro human megakaryocytic colonies

Summary We examined whether recombinant cytokines enhance the in vitro platelet production of interleukin‐3 (IL‐3)‐induced human megakaryocytic colonies (Meg‐colony). We classified Meg‐colonies into four categories based on platelet production during in situ observation on day 14: type 0, absence of cytoplasmic processes in a colony; type 1, one to three processes in at least one megakaryocyte in a colony; type 2, four to eight processes; type 3, more than nine processes or division of cytoplasm. Type 3 colonies were considered to be platelet‐producing. In control cultures, type 1 Meg‐colonies were dominant, followed by type 2, type 3 and type 0. Of the cytokines added at the initiation of culture, interleukin‐1 alpha (IL‐1α), interleukin‐6 (IL‐6), and granulocyte/macrophage colony stimulating factor (GM‐CSF) significantly increased the number of colonies. Furthermore, these three cytokines significantly elevated the proportion of type 3 colonies. Interleukin‐4 (IL‐4), granulocyte‐CSF, macrophage‐CSF and erythropoietin did not affect the colony count or distribution of colony type. IL‐1α. IL‐6 and GM‐CSF also significantly elevated the proportion of type 3 colonies, even when added to the culture on days 8 or 11. These results indicate that IL‐1α, IL‐6 and GM‐CSF promote platelet production of in vitro Meg‐colonies.