# CHARACTERIZATION OF MELANOMA GROWTH ACTIVITY

> **NIH NIH R01** · EMORY UNIVERSITY · 1988 · $76,769

## Abstract

The investigations focus on the characterization of an endogenous growth
factor produced by malignant melanoma cells and the description of the
early expression of this growth factor in premalignant nevi.  An
autostimulatory growth factor for melanocytes has been isolated and
partially characterized.  This melanoma growth stimulatory activity (MGSA)
resides in a family of antigenically related, acid and heat stable
polypeptides which appear to be different from other previously described
growth factors.  MGSA is not detectable in chromosomally normal, inactive
nevi, but nevi exhibiting chromosomal abnormalities are MGSA positive.
MGSA can be purified from acetic acid extracts of lyophilized culture
medium conditioned by the Hs0294 human melanoma cell line.  When this
extract is subjected to molecular sieve chromatography, RP-HPLC and
preparative gel electrophoresis, low (greater than 14-16Kd) and high
(24-26Kd) molecular weight forms of MGSA can be isolated.  MGSA is
separable from the 125I-EGF competing Class I TGF activity which is also
produced by this cell line.  MGSA can also be purified by immunoaffinity
chromatography using a monoclonal antibody to MGSA, followed by gel
filtration HPLS.  When immunoprecipitates from 35S-methionine labeled
extracts of Hs0294 cells were subjected to reducing SDS-PAGE followed by
autoradiography, the major labeled bands had a Mr of greater than 20Kd.
Efforts will now be directed toward:  (1) determining the relationship
between below the low and high molecular weight forms of MGSA and
developing an invitro translation system to determine the nature of the
precursor form of MGSA; (2) developing a radioreceptor assay for MGSA;
(MGSA will be purified by the methods described above, iodinated using
Bolton-Hunter reagent and binding assays will be developed using Hs0294 and
NRK cells) (3) characterizing the MGSA receptor in isolated plasma membrane
preparations using 125I-MGSA and the bifunctional cross-linking reagent,
disuccinimidyl suberate; (4) comparing the cellular distribution of
bioactive and immunoreactive MGSA and the distribution of MGSA receptors in
normal nevi, malignant melanomas, and non-malignant and non-melanoma
malignant controls.  Nevus, melanoma and other tumor cells will be cultured
in vitro, MGSA production will be determined by immunohistochemical and
bioactivity assays, and MGSA receptor distribution will be evaluated using
the MGSA-radioreceptor assay.  Comparisons will be made regarding MGSA
binding versus biological response to MGSA in these cultures.

## Key facts

- **NIH application ID:** 3172323
- **Project number:** 5R01CA034590-06
- **Recipient organization:** EMORY UNIVERSITY
- **SAM.gov UEI:** S352L5PJLMP8
- **Principal Investigator:** Ann Richmond
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1988
- **Award amount:** $76,769
- **Award type:** 5
- **Project period:** 1983-04-01 → 1989-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3172323

## Citation

> US National Institutes of Health, RePORTER application 3172323, CHARACTERIZATION OF MELANOMA GROWTH ACTIVITY (5R01CA034590-06). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3172323. Licensed CC0.

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