Direct therapeutic targeting of immune checkpoint PD-1 in pancreatic cancer

Abstract

BackgroundPancreatic cancer (PC) hijacks innate cellular processes to promote cancer growth. We hypothesized that PC exploits PD-1/PD-L1 not only to avoid immune responses, but to directly enhance growth. We also hypothesized that immune checkpoint inhibitors (ICIs) have direct cytotoxicity in PC. We sought to elucidate therapeutic targeting of PD-1/PD-L1.MethodsPD-1 was assessed in PC cells, patient-derived organoids (PDOs), and clinical tissues. Then, PC cells were exposed to PD-L1 to evaluate proliferation. To test PD-1/PD-L1 signaling, cells were exposed to PD-L1 and MAPK was examined. Radio-immunoconjugates with anti-PD-1 drugs were developed to test uptake in patient-derived tumor xenografts (PDTXs). Next, PD-1 function was assessed by xenografting PD-1-knockdown cells. Finally, PC models were exposed to ICIs.ResultsPD-1 expression was demonstrated in PCs. PD-L1 exposure increased proliferation and activated MAPK. Imaging PDTXs revealed uptake of radio-immunoconjugates. PD-1 knockdown in vivo revealed 67% smaller volumes than controls. Finally, ICI treatment of both PDOs/PDTXs demonstrated cytotoxicity and anti-MEK1/2 combined with anti-PD-1 drugs produced highest cytotoxicity in PDOs/PDTXs.ConclusionsOur data reveal PCs innately express PD-1 and activate druggable oncogenic pathways supporting PDAC growth. Strategies directly targeting PC with novel ICI regimens may work with adaptive immune responses for optimal cytotoxicity.

Chemotherapy regimens induce inhibitory immune checkpoint protein expression on stem-like and senescent-like oesophageal adenocarcinoma cells

“…Emerging studies have shown that melanoma and breast cancer stem-like cells were enriched for the expression of PD-1 and PD-L1 [12] , respectively. Recent studies have demonstrated that activation of both inhibitory IC ligands and receptors including PD-L1, PD-L2, TIM-3 and PD-1 on the surface of cancer cells promoted various immune-independent hallmarks of cancer such as an altered metabolism, proliferation, invasion and metastasis, DNA repair and chemoresistance [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , and immune checkpoint blockade (ICB) suppressed various hallmarks of cancer including invasion, chemoresistance, proliferation, glycolysis and DNA repair [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] .…”

An Organotypic Microcosm for the Pancreatic Tumor Microenvironment

“…While cell lines are commercially available and can rapidly develop into organoids, they have limitations in their ability to accurately represent characteristics of the primary tumor. Therefore, studies have turned attention to human tissue-derived organoids obtained from surgery or biopsy [6][7][8]. Unlike cell line-derived organoids, patient-derived organoids contain a lumen, multiple cell types, and apicobasal polarity [12].…”

“…Organoid culture has gained interest as a valuable in vitro model of molecular interactions and drug sensitivity testing [6]. Organoids are 3D models that have been created from human and murine normal and tumor tissues, and human-derived organoids have been created from biopsy specimens and bulk surgical tissues [6][7][8]. They maintain tumor architecture, genetic profiles, and epigenetic changes of the tissue of origin [9].…”

“…The methods for establishing PDAC organoids from biopsy specimens and surgical tissues have been described [6][7][8]. Once tumor tissues have been obtained, they are placed immediately in organoid media.…”

“…Once digested and washed, the specimens are suspended in Matrigel and plated on pre-warmed culture plates. The organoids are overlaid with complete organoid medium containing growth factors and other supplements such as Wnt, R-Spondin, Noggin, epidermal growth factor, fibroblast growth factor 10, B27 supplement, N-acetylcysteine, Gastrin, Primocin, nicotinamide, and Y27632 [6,7]. Organoids begin to grow within 1-2 days and once 80% confluent, they are passaged and may be expanded into additional wells or frozen for later use [7,8].…”