Potential impact of NOTCH1 activation on venetoclax sensitivity in chronic lymphocytic Leukaemia: In vitro insights...

Area of Science:

• Hematology
• Oncology
• Molecular Biology

Background:

• Chronic lymphocytic leukemia (CLL) treatment faces challenges due to therapy resistance.
• NOTCH1 pathway activation is a frequent event in CLL and is associated with a poor prognosis.
• Understanding mechanisms of resistance is crucial for improving CLL patient outcomes.

Purpose of the Study:

• To investigate the effect of NOTCH1 signaling on venetoclax sensitivity in CLL cells.
• To determine if NOTCH1 activation confers resistance to venetoclax therapy.
• To explore the potential for NOTCH1-activated CLL cells to evade venetoclax treatment.

Main Methods:

• In vitro assessment of venetoclax sensitivity in CLL cells with and without NOTCH1 activation.
• Ex vivo cell competition assays to compare the growth of wild-type and NOTCH1-activated CLL cells under venetoclax pressure.
• Analysis of NOTCH1 signaling impact on drug response.

Main Results:

• NOTCH1 activation showed minimal impairment of CLL cell susceptibility to venetoclax in vitro.
• Ex vivo studies demonstrated that CLL cells with constitutive NOTCH1 activation outgrew wild-type cells during continuous venetoclax exposure.
• These findings indicate an enhanced capacity for NOTCH1-activated cells to survive and potentially develop resistance.

Conclusions:

• NOTCH1 activation alone is insufficient to cause immediate venetoclax refractoriness in CLL.
• However, NOTCH1 activation provides a survival advantage, facilitating the escape of CLL cells from venetoclax treatment.
• This suggests a mechanism by which CLL cells with NOTCH1 activation may eventually achieve complete resistance to venetoclax, highlighting the importance of targeting this pathway.