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Growth-promoting effect of oestriol in a lymphoma lacking oestrogen receptors
Abstract:
Various doses (1 microgram to 10 mg) of oestriol (E3) were intraperitoneally injected into mice immediately after subcutaneous inoculation of an oestrogen receptor-negative lymphoma cell line (KE-5) established from a spontaneously developed AKR thymic lymphoma. The growth of KE-5 cells was markedly promoted by E3 at the early stage of tumour growth. At this stage, 1 microgram E3 enhanced tumour growth significantly and the maximum effect was obtained with 1 mg E3. Normal female mice showed a higher incidence and shorter latency than males. However, once tumours became palpable, the tumour growth rate appeared to be unaffected. Histological observations using Alcian blue and colloidal iron revealed a marked increase of hyaluronic acid in the subcutaneous connective tissue of the tumour-injection site within 3-5 days after intraperitoneal administration of 1 mg E3. Biochemical analyses showed a rapid and marked increase in skin hyaluronic acid content to over 3 times the control levels (0.25 +/- 0.10 mg g-1 skin) within 3 days of E3 administration. Subcutaneous inoculation of KE-5 cells together with hyaluronic acid (0.2 mg) resulted in markedly enhanced tumour growth, particularly at the early stage. These results suggest that an increase in stromal hyaluronic acid content is the most likely mechanism responsible for the promoting effect of E3 on KE-5 cells.
Insights
Oestriol (E3) promotes early-stage lymphoma growth in mice by increasing hyaluronic acid. This suggests a novel mechanism for oestrogen
Area of Science:
- Oncology
- Endocrinology
- Biochemistry
Background:
- Oestrogen receptor-negative lymphoma cell lines present unique challenges in cancer research.
- The role of hormones in tumour microenvironment modulation requires further investigation.
Purpose of the Study:
- To investigate the effect of oestriol (E3) on the growth of oestrogen receptor-negative lymphoma cells (KE-5) in mice.
- To elucidate the underlying mechanism of E3-mediated tumour promotion.
Main Methods:
- Intraperitoneal injection of varying doses of E3 into mice bearing KE-5 lymphoma xenografts.
- Histological analysis using Alcian blue and colloidal iron staining.
- Biochemical quantification of hyaluronic acid in skin tissue.
Main Results:
- E3 significantly promoted early-stage KE-5 tumour growth, with optimal effect at 1 mg.
- A marked increase in subcutaneous hyaluronic acid was observed following E3 administration.
- Co-inoculation of KE-5 cells with hyaluronic acid enhanced tumour growth.
Conclusions:
- Increased stromal hyaluronic acid content is a likely mechanism for E3-induced promotion of KE-5 lymphoma growth.
- These findings highlight the complex interplay between hormones and the tumour microenvironment.