(493) Effects of chemotherapy agents on placental cells: implications for treating breast cancer during pregnancy

Objective: To examine anti-proliferative and cytotoxic effects of three breast cancer chemotherapeutics (5-fluorouracil (5-FU), doxorubicin (DXR), and cyclophosphamide (CP)) on human placental cell lines JAR and JEG-3. Tamoxifen (TAM) a hormone therapy contraindicated in pregnancy was also examined.

Study Design:

JAR and JEG-3 cell lines (ATTC) were used as human placental cell models.

Cell Proliferation: JAR and JEG-3 cells were plated at 5x10³/well in media containing 10% FBS in 96 well plates. Cells were treated with chemotherapeutic agents (using a range of doses, n=4 wells/condition, n>3 experiments). After 48 hours at 37°C/5% CO₂, cells were processed for proliferation using the CyQUANT assay kit (Invitrogen) to determine relative cell numbers.

Cytotoxicity: JAR and JEG-3 cells were plated at 3x10⁴ cells per well and 6x10⁴ cells per well, respectively, in 96 well plates in media containing 10% FBS. Cells were treated with chemotherapeutic agents (using a range of doses, n=6 wells/condition, n>3 experiments). After 48 hours at 37°C/5% CO₂, cytotoxicity was determined by neutral red staining.   

A 3-parameter nonlinear regression model (GraphPad Prism Version 10.0.0) was used to calculate half maximal inhibitory concentrations (IC₅₀) for cell proliferation and cytotoxicity for each agent. Extra sum of squares F-test was used to compare IC₅₀ values between cell lines for each chemotherapeutic agent.
 

 

 

Results:

Chemotherapeutic IC₅₀ values are shown in Table 1. DXR was the most and CP was the least anti-proliferative and cytotoxic. 5-FU and TAM had significantly higher anti-proliferative effects on JEG-3 than JAR cells. The cytotoxic effects of DXR were significantly higher for JEG-3 than JAR while the inverse was true for TAM. Overall, chemotherapeutic dosages that induced cytotoxicity were similar to those that inhibited proliferation, except CP, which showed more potent cytotoxic than anti-proliferative effects.

Conclusion: DXR exerted the most potent anti-proliferative and cytotoxic effects. Further studies comparing the effects of these agents on breast cancer and placental cell lines are warranted.