The Formation of Stable Lung Tumor Spheroids during Random Positioning Involves Increased Estrogen Sensitivity

Area of Science:

• Oncology
• Biotechnology
• Cell Biology

Background:

• Tumor spheroid formation on the random positioning machine (RPM) is crucial for studying metastasis ex vivo but remains poorly understood.
• Understanding cell-type specific responses to RPM conditions is key to optimizing spheroid formation for research.

Purpose of the Study:

• To compare RPM-induced spheroid formation in NCI-H1703 squamous cell carcinoma and Calu-3 adenocarcinoma cells.
• To investigate the molecular mechanisms underlying differential spheroid formation and stability.

Main Methods:

• Comparative analysis of NCI-H1703 and Calu-3 cells on the RPM.
• Assessment of cell adhesion protein expression (Mucin-1, β1-integrin, E-cadherin).
• Gene expression analysis of estrogen receptor alpha (ESR1) and effects of 17β-estradiol/phenol red.

Main Results:

• NCI-H1703 cells readily formed stable spheroids, while Calu-3 cells formed unstable spheroids or remained as cell layers.
• Calu-3 cells exhibited lower Mucin-1 expression and higher adhesiveness, with unstable spheroids linked to imbalanced adhesion proteins.
• RPM-exposed Calu-3 cells showed upregulated ESR1; 17β-estradiol or phenol red enhanced Calu-3 spheroid stability.

Conclusions:

• RPM-induced tumor spheroid formation is influenced by cell-type specific properties and the interplay between mechanical forces and medium composition.
• Adhesion protein balance and estrogen receptor signaling play significant roles in the stability of lung carcinoma spheroids under simulated microgravity.
• Optimizing experimental conditions, including medium formulation, can enhance the formation of stable tumor spheroids for ex vivo metastasis studies.