Résumé
BACKGROUND – ATP-binding cassette (ABC) transporters represent the largest superfamily of transmembrane proteins composed of 48 transporters divided into seven families, named from A to G. ABC transporters have been extensively studied for their implication in chemoresistance. In the past decade, they received more attention for their potential role in tumor biology, which led to unravel their role in tumor development and progression. The ABCB family is composed of four full-transporters and eight half-transporters, which must either homo- or heterodimerize to become functional. This research project focuses on ABCB6 and ABCB9, two half ABCB transporters, which were previously shown to heterodimerize in engineered HEK293T cells using co-immunoprecipitation and NanoBRET.AIMS – This study aims to further investigate the heterodimerization of ABCB6 and ABCB9 in three different cell lines, which we hypothesize they constitutively express them.
METHODS –RT-qPCR and western blot were used to study the mRNA and protein expression of ABCB6 and ABCB9 in the 3 chosen cell lines, which are the MDA-MB-231 breast cancer cell line, the MDA-MB-435 melanoma cell line, and the immortalized Sertoli cells. Then, subcellular fractionation was used to investigate the localization of both transporters in MDA-MB-231 and MDA-MB-435 cell lines. Lastly, co-immunoprecipitation was performed to study their potential heterodimerization.
RESULTS – mRNA and protein expression of ABCB6 and ABCB9 have been detected in each cell lines except protein expression of ABCB6, which was not detected in the Sertoli cells. Regarding the localization, both transporters have been localized in the soluble cytosolic fraction, which gave rise to many questions as they are both transmembrane proteins. We were not able to show the heterodimerization of ABCB6 and ABCB9 using co-immunoprecipitation.
CONCLUSION – ABCB6 and ABCB9 are both expressed at the mRNA and protein levels in MDA- MB-231 and MDA-MB-435 cell lines. In Sertoli cells, ABCB6 was not expressed at the protein level, whereas ABCB9 mRNA and protein were detected. The localization of both transporters remains to be investigated, as they were recovered mainly in the cytosolic fraction. Lastly, the heterodimerization of ABCB6 with ABCB9 could not be validated.
| la date de réponse | 19 janv. 2021 |
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| langue originale | Anglais |
| L'institution diplômante |
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| Superviseur | Jean-Pierre Gillet (Promoteur) |