Reducing the Invasiveness of Low- and High-Grade Endometrial Cancers in Both Primary Human Cancer Biopsies and Cell Lines by the Inhibition of Aquaporin-1 Channels

by Selleckchem | Nov 21 2023

Aquaporin (AQP) channels in endometrial cancer (EC) cells are of interest as pharmacological targets to reduce tumor progression. A panel of compounds, including AQP1 ion channel inhibitors (AqB011 and 5-(phenoxymethyl) furan-2-carbaldehyde, PMFC), were used to test the hypothesis that inhibition of key AQPs can limit the invasiveness of low- and high-grade EC cells. We evaluated the effects on transwell migration in EC cell lines (Ishikawa, MFE-280) and primary EC cells established from surgical tissues (n = 8). Quantitative PCR uncovered classes of AQPs not previously reported in EC that are differentially regulated by hormonal signaling. With estradiol, Ishikawa showed increased AQPs 5, 11, 12, and decreased AQPs 0 and 4; MFE-280 showed increased AQPs 0, 1, 3, 4, 8, and decreased AQP11. Protein expression was confirmed by Western blot and immunocytochemistry. AQPs 1, 4, and 11 were colocalized with plasma membrane marker; AQP8 was intracellular in Ishikawa and not detectable in MFE-280. AQP1 ion channel inhibitors (AqB011; PMFC) reduced invasiveness of EC cell lines in transwell chamber and spheroid dispersal assays. In Ishikawa cells, transwell invasiveness was reduced ~41% by 80 µM AqB011 and ~55% by 0.5 mM 5-PMFC. In MFE-280, 5-PMFC inhibited invasion by ~77%. In contrast, proposed inhibitors of AQP water pores (acetazolamide, ginsenoside, KeenMind, TGN-020, IMD-0354) were not effective. Treatments of cultured primary EC cells with AqB011 or PMFC significantly reduced the invasiveness of both low- and high-grade primary EC cells in transwell chambers. We confirmed the tumors expressed moderate to high levels of AQP1 detected by immunohistochemistry, whereas expression levels of AQP4, AQP8, and AQP11 were substantially lower. The anti-invasive potency of AqB011 treatment for EC tumor tissues showed a positive linear correlation with AQP1 expression levels. In summary, AQP1 ion channels are important for motility in both low- and high-grade EC subtypes. Inhibition of AQP1 is a promising strategy to inhibit EC invasiveness and improve patient outcomes.

Comments:

The passage you provided describes a research study focused on investigating the role of Aquaporin 1 (AQP1) ion channels in endometrial cancer (EC) cells and exploring their potential as pharmacological targets to reduce tumor progression. The study involved testing a panel of compounds, including AQP1 ion channel inhibitors AqB011 and 5-(phenoxymethyl) furan-2-carbaldehyde (PMFC), to determine their effects on the invasiveness of low- and high-grade EC cells.

Here's a summary of the key findings from the study:

1. **AQP Expression and Regulation:**
- Different classes of AQPs were identified in EC cells, some of which were regulated by hormonal signaling.
- Estradiol treatment led to specific changes in the expression levels of different AQPs in EC cell lines (increased AQPs 5, 11, 12, and decreased AQPs 0 and 4 in Ishikawa cells; increased AQPs 0, 1, 3, 4, 8, and decreased AQP11 in MFE-280 cells).

2. **Localization and Confirmation:**
   - Protein expression of AQPs 1, 4, and 11 was confirmed through Western blot and immunocytochemistry.
   - AQP1, 4, and 11 were found to be localized on the plasma membrane, indicating their presence in the cell membrane.
   - AQP8 was found to be intracellular in Ishikawa cells and undetectable in MFE-280 cells.

3. **Inhibition of AQP1 Ion Channels:**
- AQP1 ion channel inhibitors, AqB011, and PMFC significantly reduced the invasiveness of EC cell lines (Ishikawa and MFE-280) in transwell chamber and spheroid dispersal assays.
- AqB011 and 5-PMFC showed significant inhibitory effects on EC cell invasion, while other inhibitors targeting AQP water pores were not effective.

4. **Primary EC Cells:**
- Treatment with AqB011 or PMFC reduced the invasiveness of both low- and high-grade primary EC cells in transwell chambers.

5. **Correlation with AQP1 Expression:**
- Immunohistochemistry confirmed moderate to high levels of AQP1 expression in EC tumor tissues.
- The anti-invasive effects of AqB011 treatment were positively correlated with AQP1 expression levels in the tumors.

**Conclusion:**
The study suggests that AQP1 ion channels play a crucial role in the motility of both low- and high-grade EC subtypes. Inhibition of AQP1 using specific inhibitors (AqB011 and PMFC) appears to be a promising strategy to reduce EC invasiveness. This finding has implications for the development of targeted therapies to improve outcomes for EC patients.