Pattern analysis of microtubule-polymerizing and -depolymerizing agent combinations as cancer chemotherapies

Area of Science:

• Cell Biology
• Pharmacology
• Oncology

Background:

• Subcellular mass distribution analysis using cell culturing on interferometers yields 102 variables predicting oncogenic transformation.
• Latent factors derived from these variables deconstruct cell phenotypes, with prior studies showing reversal of cancer phenotypes using combined microtubule-stabilizing and -depolymerizing agents.

Purpose of the Study:

• To investigate the effects of various drug combinations on cell phenotype and cell cycle phases beyond mitosis.
• To analyze clinical delivery schedules and drug ratios for combination therapies.

Main Methods:

• Culturing cells on interferometers to analyze subcellular mass distribution via interference contours.
• Utilizing latent factor analysis to deconstruct cell phenotypes.
• Treating cells with combinations of paclitaxel (or its analogue 7-deoxytaxol) with agents like colchicine, podophyllotoxin, nocodazole, or vinblastine.
• Assessing changes in specific phenotypic factors (e.g., filopodia, cell periphery, p21-activated kinase, cell rounding) and microtubule arrangement.

Main Results:

• Combinations of paclitaxel with other agents, and 7-deoxytaxol alone, reversed cancer-type phenotypes.
• Specific factors shifted towards normal cell values (e.g., filopodia), while others shifted towards cancer-type values (e.g., p21-activated kinase, cell rounding).
• All tested combinations altered microtubule arrangement at the cell edge.
• Clinical response rates were significantly better with simultaneous combination therapy compared to interspersed single-agent treatment (P=0.004).

Conclusions:

• Efficacy of combination therapies relies on simultaneous exposure to both agents.
• These therapies offer a novel mechanism by restoring contact inhibition features and impeding cell cycle progression in transformed cells, even at nanomolar concentrations.