74: In Vivo Analysis of Protein Level Effects of Hyperthermic Intraperitoneal Chemotherapy

Peritoneal carcinomatosis is frequently refractory to systemic chemotherapeutic agents. Selected patients are offered cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) in an attempt to improve locoregional control. However, HIPEC agents are chosen based on primary histology, and individuals’ treatment responses are variable. We endeavored to better understand the tissue-level effects following HIPEC administration to elucidate the pathways associated with treatment response. 


Methods:

With IRB approval on NCT04847063, peritoneal metastases were collected prior to and following HIPEC with cisplatin and doxorubicin. Proteolytic digestion was performed on snap frozen samples. Samples were tagged with TMTpro, and phosphopeptide enrichment was employed prior to mass spectrometry analysis. Using the UniProt Human database, proteins and phosphoproteins were identified. Analyses were conducted using Proteome Discover 2.4 and R Studio 4.3.   


Results:

Among patients with peritoneal carcinomatosis from ovarian primaries, peritoneal metastases were evaluated immediately before (pre-HIPEC) and immediately after (post-HIPEC) 60-minute intraperitoneal cisplatin and doxorubicin perfusion. Individual protein/phosphoprotein expression was compared between paired pre- and post-HIPEC samples. Overall, 3,456 proteins were identified in >4 samples. Comparative analysis revealed that expression of 105 proteins was significantly different between pre- and post-HIPEC specimens (p-adj< 0.05); 60 proteins were downregulated and 45 were upregulated. Biological pathway analysis identified changes in complement, TNF-alpha signaling via NF-kB, and reactive oxygen species pathways (p< 0.05). Overall, 4,870 phosphopeptides were identified in >4 samples. Comparative analysis revealed that expression of 204 phosphoproteins was significantly changed between pre- and post-HIPEC specimens (p-adj< 0.05); 69 were dephosphorylated and 135 were phosphorylated. Biological pathway analysis identified changes in mitotic spindle formation and hypoxia pathways (p< 0.05).


Conclusions:

Herein we report proteomic and phosphoproteomic analyses using in vivo human tissue following administration of cisplatin and doxorubicin HIPEC. Early alterations in proteomic and phosphoproteomic expression following HIPEC will improve understanding individuals’ treatment responses and may support personalization of HIPEC treatment.