IDDF2023-ABS-0190 EUS-FNB combined with single-cell transcriptome predict response and reveal tumor microenvironment remodeling during chemotherapy in advanced pancreatic ductal adenocarcinoma

Background

Advanced pancreatic ductal adenocarcinoma (PDAC) relies on systematic chemotherapy, while the response rate is low. The relationship between tumor microenvironment (TME) remodeling and treatment response is still unclear. We aimed to reveal the dynamic changes of TME during chemotherapy and identify key regulators in chemoresistance by combining endoscopic ultrasound-guided fine needle biopsy (EUS-FNB) with single-cell RNA sequencing (scRNA-seq).

Methods

We performed scRNA-seq of pre-and post-treatment EUS-FNB biopsies and blood from 18 PDAC patients receiving Abraxane plus gemcitabine chemotherapy (AG). The patients were evaluated after 3 cycles of chemotherapy (divided into responders (n = 8) and non-responders (n = 10)).

Results

We collected 24 fresh biopsies through EUS-FNB, including 14 pre-treatment and 10 paired post-treatment tumor specimens following AG chemotherapy. Based on the scRNA-seq analysis, we obtained a total of 86,432 cells including epithelial cells (malignant cells, acinar), immune cells (T/NK, B/Plasma, neutrophils, monocytes, macrophages, DCs, and mast cells), stromal cells (fibroblast, stellate cell, and endothelial cells) and proliferating cells. We identified an intermediate transcriptional state in PDAC, where tumor cells convert to SNCG⁺ (basal-like state) and GPX2⁺ (classical state) tumor cells associated with chemoresistance and chemosensitivity, respectively. In responders, GPX2⁺ tumor cells, FOLR2⁺ tissue-resident macrophages, and CD8⁺ T effect cells concertedly increased during the chemotherapy, activating anti-tumor TIME with increasing phagocytosis and interferon gamma production. While SNCG⁺ tumor cells expressing high levels of CD276 strongly interacted with pro-angiogenic SPP1⁺ tumor-associated macrophages and exhausted T cells driving chemo-resistance. Meanwhile, the anti-CD276 and chemotherapy combination dramatically reduced the tumor volume and increased the OS of tumor-bearing KPC mice.

Conclusions

Advanced PDAC patients with a high proportion of SNCG⁺ tumor cells, SPP1⁺ macrophages Tex at baseline may indicate an ineffective AG chemotherapy. Moreover, this work highlights tumor conversion and interaction with TIME as major determinants of chemotherapy outcomes and identifies targeting CD276, a key driver of the tumor state, as a potential strategy to reverse chemo-resistance in PDAC.