PKD3 (Polycystic Kidney Disease 3)

These findings highlight PKD isoforms as potential therapeutic targets, particularly in cancer settings where metabolic dysfunction plays a contributing role. While current PKD inhibitors lack isoform specificity, future therapeutic strategies focused on PKD2 and PKD3 modulation may offer selective control over invasion, immune evasion, and metabolic reprogramming in metabolically comorbid cancer patients.

This correlates with impaired endosomal acidification, which is associated with dysregulated Wnt signaling and a decline in stemness. Our data thus unveil a previously unrecognized role of PKD3 in regulating endolysosomal dynamics that contributes to the maintenance of the cancer stem cell population in TNBC.

Our results suggest that Prkd3 modulates proliferation through the regulation of gene expression associated with glucose metabolism (Tnf, Ucp2, Pgam2, Angptl4), calcium homeostasis and transport (Calcr and P2rx7) and microtubule dynamics (Stmn2 and Map10). These candidate processes and associated genes represent potential mechanisms involved in Prkd3-induced proliferation in spontaneously immortalized cells as well as clinical targets in several cancer types.

However, the role of PKD3 was elusive in some cancers. Our findings suggest that testing for PKD isotypes with immunohistochemistry may support the diagnostic estimation of tumor progression and prognosis in HNSCC with a potential therapeutic relevance.

Lastly, the observed alterations in the CD8+ T cell compartment did not impact proper immune response upon immunization with ovalbumin or in a subcutaneous tumour model suggesting only a small to absent biological relevance. Taking together the knowledge of all our published studies on PKD3 in the T cell compartment, we now conclude that T cell-intrinsic PKD3 is a fine-tuner of central memory T cell as well as CD8 single positive thymocyte development.

Consistently, PKD-dependent secretion of pro-invasive factors was more pronounced in metastatic TNBC cell lines. Our study thus uncovers a novel role of PKD2 in releasing a pro-invasive secretome.

Thus, PC patients with the expression pattern: active PKD2/active ERK/Snail exhibit increased invasiveness and metastasis, and decreased survival. Our findings provide new insights for understanding the molecular mechanisms involved in PC progression, pinpointing the combination of active PKD2 and Snail levels, with the additional measurement of active ERK, as a confident biomarker to predict clinical outcome of patients with advanced PC.

Mechanistically, PKD2 and PKD3 positively regulated Runx2 via MAPK/ERK1/2 pathway and promoted EOC. Taken together, our results indicated that PKD2/3/ERK1/2/Runx2 signalling axis might be a novel drug target against EOC and CRT0066101 could be developed as a promising therapeutic choice against this lethal pathology.

Furthermore, inhibition of PKD by CRT0066101 potently decreased the frequency of bone micrometastases in a mouse model of bone metastasis based on intracardiac injection of PC3-ML cells. These results indicate that PKD2/3 play an important role in the bone metastasis of prostate cancer cells, and their inhibition may be beneficial for the treatment of advanced stages of prostate cancer.