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Lapatinib inhibits meiotic maturation of porcine oocyte-cumulus complexes cultured in vitro in gonadotropin-supplemented medium.

Significance Statement

It has been shown that epidermal growth factor receptor (EGFR) mediates the ovulatory response to LH in the ovarian follicle and the sustained activity of EGFR is an absolute requisite for LH-induced oocyte maturation and cumulus expansion. However, abnormally elevated EGFR kinase activity can lead to various pathological states, including proliferative diseases such as cancer. The human epidermal growth factor receptor (HER) family consists of four closely related transmembrane receptors: HER1 (human epidermal growth factor receptor 1, EGFR), HER2/c-Erb-B2, HER3/Erb-B3 and HER4/Erb-B4. These members of the type I receptor tyrosine kinase family are frequently implicated in cancer. HER family-related downstream signaling plays a crucial role in cell proliferation, survival, migration and differentiation. Several reversible and irreversible small molecule tyrosine kinase inhibitors with varying degrees of selectivity have been developed (erlotinib, gefitinib, lapatinib, afatinib). Our work focuses on lapatinib (GW572016, Tykerb/Tyverb; GlaxoSmithKline), an orally active small molecule, that reversibly and selectively inhibits the tyrosine kinase domain of both EGFR and HER2 by binding to the ATP-binding site of the kinase, preventing autophosphorylation or rapid development of resistance to monotherapies. ^It has been demonstrated that FSH promotes maturation of the EGF-response pathway in porcine OCC, as evidenced by a strong increase in EGF-induced EGFR tyrosine kinase phosphorylation, synthesis of hyaluronan (HA) and subsequently cumulus expansion.

To date, no studies reported the effect of lapatinib on processes essential for ovulation and pregnancy; such as oocyte maturation, HA synthesis by cumulus cells, expression of cumulus expansion related transcripts, cumulus expansion and steroidogenesis. Nevertheless, it has been suggested that the increasing use of biological agents among cancer women increases the probability that some women will conceive while taking a growth factor pathway inhibitor.

Therefore, we asked whether lapatinib through EGFR tyrosine kinase inhibition is able to affect the final processes of oocyte meiotic maturation before ovulation.

We found that lapatinib is able to inhibit oocyte maturation. Moreover, lapatinib is able to reduce the expression of ovulation-related transcripts (PTGS2, TNFAIP6), cumulus expansion, synthesis of hyaluronan and progesterone secretion by OCC cultured in vitro in FSH/LH-supplemented medium. We have further demonstrated that OCC are sensitive to lapatinib-mediated inhibition of EGFR pathway.

Journal Reference

Nagyova E, Nemcova L, Mlynarcikova A, Scsukova S, Kalous J.

Fertil Steril. 2013 May;99(6):1739-48.

Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Libechov, Czech Republic. [email protected]

Abstract

OBJECTIVE:

To determine whether inhibition of epidermal growth factor (EGF) receptor tyrosine kinase with lapatinib affects oocyte maturation, expression of the cumulus expansion-associated genes such as tumor necrosis factor alpha-induced protein 6 (TNFAIP6) and prostaglandin-endoperoxide synthase 2 (PTGS2), and synthesis of hyaluronan (HA) and progesterone (P) by porcine oocyte cumulus complexes (OCC).

DESIGN:

Our work focuses on lapatinib, an orally active small molecule that selectively inhibits the tyrosine kinase domain of both EGF receptor and human EGF receptor 2, and downstream signaling.

SETTING:

A reproductive biology laboratory.

INTERVENTION(S):

Porcine OCC were cultured in vitro in a medium with FSH/LH in the presence/absence of lapatinib.

MAIN OUTCOME MEASURE(S):

Methods performed: real-time reverse transcriptase-polymerase chain reaction (PCR), immunofluorescence, RIA.

RESULT(S):

In FSH/LH-stimulated and expanded cumulus oophorus extracellular matrix, HA was detected with biotinylated HA-binding proteins. However, weaker HA- and weaker cytoplasmic TNFAIP6 were detected were detected in lapatinib-pretreated OCC. The expression of the two cumulus expansion-associated gene transcripts was significantly decreased and synthesis of HA by cumulus cells was reduced. Lapatinib (10 uM) inhibited FSH/LH-induced oocyte meiotic maturation. Progesterone production increased after OCC stimulation with FSH/LH and was significantly decreased by lapatinib (10 uM).

CONCLUSION(S):

Lapatinib inhibits oocyte maturation and reduces expression of cumulus expansion-associated transcripts, and synthesis of HA and P in OCC cultured in vitro in FSH/LH-supplemented medium.

Copyright © 2013 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

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