Abstract
Although cell cultures from marine invertebrates have great potential as valuable tools in various scientific fields, nearly all attempts to culture these cells in vitro have consistently failed, and the reasons for this remain unclear. The ongoing failure to develop stable, long-term cell cultures from marine invertebrates, despite varied species and methods employed, highlights significant knowledge gaps in understanding their in vitro requirements. These gaps impede progress, underscoring the complexity of marine invertebrate cells and the need for innovative approaches to overcome challenges in the field. When reviewing recent literature on the key data deficiencies and challenges behind the failure to develop marine invertebrate cell cultures, we identified and discussed four major knowledge gaps: (1) optimizing culture media, (2) strategies to extend stemness of isolated cells, (3) using "omics" to enhance cell culture, and (4) selecting suitable cell types for in vitro cultures. Bridging these gaps is crucial for advancing marine invertebrate cell culture systems. Yet, given the current state-of-the-art, addressing these gaps and advancing the discipline necessitate comprehensive, integrated, and species- or cell-specific strategies, along with close collaboration among laboratories working on diverse species.