Calcium Homeostasis Machinery in the Human Uterus-A Potential Therapeutic Target in Endometrial Cancer

Endometrial cancer is one of the most common malignancies of the female reproductive system, with incidence rising globally due to population ageing and life-style-related risk factors. Calcium (Ca²⁺) is a ubiquitous second messenger regulating diverse physiological processes, and its dysregulation has been increasingly implicated in carcinogenesis, including endometrial. Altered expression and function of Ca²⁺ channels, pumps, exchangers, and binding proteins disrupt the finely tuned balance of Ca²⁺ influx, efflux, and intracellular storage, leading to aberrant signalling that promotes tumour proliferation, migration, survival, and metastasis. This review summarises current knowledge on the molecular "Ca²⁺ toolkit" in the human uterus, highlighting the role of voltage-gated calcium channels (VGCCs), transient receptor potential (TRP) channels, store-operated calcium entry (SOCE) components, Na⁺/Ca²⁺ exchangers, purinergic receptors, P-type ATPases (SERCA, SPCA, PMCA), ryanodine (RyR) and inositol 1,4,5-trisphosphate (IP₃R) receptors, and mitochondrial Ca²⁺ uniporter (MCU) complexes in endometrial cancer progression. Multiple Ca²⁺-handling proteins, including CACNA1D, CACNA2D1, TRPV4, TRPV1, TRPM4, MCU, and RyR1, exhibit cancer-associated overexpression or functional changes, correlating with poor prognosis and aggressive disease features. Emerging evidence supports the therapeutic potential of targeting Ca²⁺ homeostasis using small-molecule inhibitors, ion channel modulators or gene-silencing strategies. These interventions may restore Ca²⁺ balance, induce apoptosis or autophagy, and suppress metastatic behaviour. While no clinical trials have yet explicitly focused on Ca²⁺ modulation in endometrial cancer, the diversity of dysregulated Ca²⁺ pathways offers a rich landscape for novel therapeutic strategies. Targeting key components of the Ca²⁺ signalling network holds promise for improving outcomes in endometrial cancer.