Clinical Case Summary

Recently, the concept of neoadjuvant therapy for unresectable locally advanced pancreatic cancer (PC) has received much attention. However, in patients who respond well to neoadjuvant therapy, even if resection is achieved, micro-cancer cells may remain around the major vessels. This may lead to early recurrence. A novel therapeutic strategy is needed to improve prognosis and achieve long-term survival. Under the situations, high-intensity focused ultrasound (HIFU) of new noninvasive therapy is expected as neoadjuvant therapy. 47-year-old man, case of PC with onset in August 2020. Initially difficult to diagnose, he developed obstructive jaundice in January 2021 and was diagnosed as pancreatic head cancer (45 mm) infiltrating CA, CHA and SMA. Surgery was not indicated and chemotherapy (GEM+nab-PTX) was administered due to unresectable locally advanced PC. The patient was referred to our hospital due to treatment response PD and was treated with second-line chemotherapy (mFFX) combined with HIFU therapy. 2 months later, the tumour showed a shrinking effect, but residual tumours adjacent to CA, CHA and SMA were observed. Therefore, to achieve negative surgical margins, HIFU was added again to the perivascular area and tumour, and total pancreatectomy and combined portal vein resection-reconstructive surgery was performed. The pathology was suspected to be positive, although some of the dissected surfaces of the pancreatic body head and dorsal were possibly altered after cauterisation. Subsequently, postoperative adjuvant chemotherapy was administered. Six months after surgery, an increase in the peri-CA soft-tissue shadow was observed and PET showed an accumulation, leading to a diagnosis of local recurrence. Therefore, systemic chemotherapy and HIFU for the soft tissue were administered again. Subsequently, a decrease in PET accumulation was observed. The combination of chemo and HIFU therapy is suggested to be a promising neoadjuvant and adjuvant therapy.

References

Sofuni A, Moriyasu F, Itoi T et al. The current potential of high-intnsity focused ultrasound for pancreatic carcinoma. J Hepatobiliary Pancreat Sci. 2011;18(3):295-303.
Sofuni A, Moriyasu F, Itoi T,et al. Safety trial of high-intensity focused ultrasound therapy for pancreatic cancer. World J Gastroenterol. 2014;20:957
Sofuni A, Asai Y, Tsuchiya T, et al. Novel therapeutic method for unresectable pancreatic cancer the impact of the long term research in therapeutic effect of high intensity focused
ultrasound (HIFU) therapy. Curr Oncol. 2021;28:4845 61.

Introduction

Pancreatic ductal adenocarcinoma (PDAC) is in the tenth place of newly diagnosed case of all tumors and one of the most lethal cancer related malignancies in developed countries [1]. Surgical reduction still is the main treatment method, but often not effective due to the advanced stage. Immunotherapy is a promising treatment for many cancers. However, the efforts and attempts to use immunotherapy in the treatment of PDAC are extensive and real breakthroughs have not been achieved [2]. Peripheral blood mononuclear cells (PBMC) as immune cells are crucial for the body's response against cancer [3]. One of the main immune checkpoint member is programmed cell death protein 1 (PD1). It is known that PD1 expression in T cells is strongly regulated by aryl hydrocarbon receptor (AHR) [4]. Moreover, there are immunological barriers to treatment challenge in cancer like insufficient immune function activation and excess immune suppression [5]. Previously we analyzed immune response disbalance regards of AHR expression in PDAC patients PBMCs. Results showed significant changes of lower AHR gene expression patients' group. Next, we decided to check PBMCs functions in healthy participants after indirect interaction with pancreatic cancer cells. We hypothesized that AHR expression differences in PBMCs could regulate anti-cancer response.

Aims & Methods

The aim of this study was to analyze PBMCs functions and targets expression of healthy participants after indirect interaction with pancreatic cancer cells. PBMCs (n=11) were isolated from peripheral blood by Ficoll-Paque gradient centrifugation. Analysis was done at 3 points. The first point of study was prepared immediately after PBMCs isolation. Second and third points were prepared after 20h of PBMCs -/+ co-cultivation with BxPC3 cells. Phagocytic activity analysis was prepared after 3-hour PBMCs activation with LPS. ROS production was measured effecting with TBHP. NO production was measured after activation with LPS + L-Arginine. Simultaneously PBMCs metabolic activity was measured by resazurin assay. Monocytes and lymphocytes differentiation was evaluated by FACS analysis. Gene expressions were analyzed by RT-PCR method. Statistical analysis was performed using GraphPad software and the Mann – Whitney test.

Results

The results showed that AHR and IL1b, IL6, IL10 mRNA were increased, only IL6 was significantly upregulated after PBMC co-cultivation with BxPC3 cells. While PD1 and IL4 mRNA expression were decreased. The expression of AHR strongly negatively correlated with expression of PD1 in healthy volunteers PBMCs’ after co-cultivation with cancer cells. M1 type monocytes and NK cells decreased after co-cultivation with PDAC cells. Moreover, M0 type monocytes and cytotoxic T lymphocytes were increased. Phagocytic activity and NO production were more intensive in PBMC cells after co-cultivation. ROS production did not show significant changes.

Conclusion

This study showed negative PD1 gene expression correlation with AHR expression after indirect interactions with cancer cells in healthy participants PBMCs. Also, PBMCs co-cultivation with cancer cells initiated strong functional response and higher expression of inflammatory cytokines. These results show us different AHR relations with immunity response in healthy and cancer patients. Meanwhile, this knowledge lets us understand the importance of AHR modulation as an additional PDAC treatment strategy.

References

1. Siegel, R. L., Miller, K. D., Wagle, N. S., & Jemal, A. (2023). Cancer statistics, 2023. CA: A Cancer Journal for Clinicians, 73(1), 17-48. doi:10.3322/caac.21763
2. Mundry, C. S., Eberle, K. C., Singh, P. K., Hollingsworth, M. A., & Mehla, K. (2020). Local and systemic immunosuppression in pancreatic cancer: Targeting the stalwarts in tumor’s arsenal. Biochimica Et Biophysica Acta. Reviews on Cancer, 1874(1), 188387. doi:10.1016/j.bbcan.2020.188387
3. Griffin JF, Poruk KE, Wolfgang CL. Pancreatic cancer surgery: past, present, and future. Chin J Cancer Res. 2015 Aug;27(4):332-48
4. Liu, Y., Liang, X., Dong, W., Fang, Y., Lv, J., Zhang, T., . . . Huang, B. (2018). Tumor-repopulating cells induce PD1 expression in CD8+ T cells by transferring kynurenine and AhR activation. Cancer Cell, 33(3), 480-494.e7. doi: 10.1016/j.ccell.2018.02.005
5. Rojas, L. A., & Balachandran, V. P. (2021). Scaling the immune incline in PDAC. Nature Reviews. Gastroenterology & Hepatology, 18(7), 453-454. doi:10.1038/s41575-021-00475-9

Disclosure

The authors have no conflicts of interest to declare

Introduction

Pancreatic cancer (PC) is one of the fatal malignant tumors, with a 5-year survival rate is approximately 6%, and is expected to become the second leading cause of cancer deaths by 2030. The poor prognosis of PC is associated with the tumour microenvironment, characterized by excessive fibrosis and extracellular matrix deposition, known as desmoplasia. PC’s highly desmoplastic property not only increases the malignancy of the tumor but also inhibits the penetration and diffusion of anti-cancer drugs, related to drug resistance. Chauhan et al. demonstrated that the angiotensin inhibitor (ASI), losartan reduced stromal collagen and hyaluronan production, thus improving the efficacy of chemotherapy in PC models. Several retrospective studies have reported that the ASI usage group showed higher overall survival (OS) and progression-free survival compared to the non-ASI usage group in PC patients. However, most of the previous studies on ASI in PC patients were based on retrospective data from single institutions. Recently, real-world big data study could explain this subject.

Aims & Methods

In this study, we aimed to conduct whether ASI use in PC patients improve OS using National Health Information Database of the National Health Insurance Service, which represents the entire Korean population. We assessed 209,723 participants for eligibility, diagnosed with pancreatic cancer between 2002 and 2020. A total of 64,219 PC patients were enrolled and divided into 3 groups [chronic ASI users with hypertension (HTN), n=13,239; non-ASI users with HTN, n=5,963; non-HTN group, n=45,017]. We performed propensity score matching to balance the baseline characteristics of the 3 groups and to reduce potential confounders using a logistic regression model with adjustment for the following: age; sex; region of residence (urban or rural); household income; underlying disease of HTN, diabetes mellitus, cardiovascular disease, cerebrovascular disease, chronic kidney disease or chronic pancreatitis; Charlson Comorbidity Index (0, 1 or ≥2); concurrent use of aspirin, metformin, statin; PC surgery type; radiotherapy; and chemotherapy.

Results

Multivariate analysis using Cox regression analysis for matched cohort presented ASI usage, female, younger, history of chronic pancreatitis, CCI ≥2, concurrent use of statin, and receiving distal pancreatectomy were significantly associated with longer OS. In addition, Kaplan-Meier curve for OS of 3 groups according to ASI usage showed that chronic ASI users presented significantly longer OS than non-ASI users and non-HTN group [Hazard ratio, chronic ASI users (control) versus non-ASI users 1.447; chronic ASI users (control) versus non-HTN group 1.518; P value < 0.001].

Conclusion

We found that the use of ASI after PC diagnosis is associated with longer survival in PC patients. Additional well-designed randomized controlled studies are needed to confirm these findings in the future.

References

1. Rahib, L., B. D. Smith, R. Aizenberg, A. B. Rosenzweig, J. M. Fleshman and L. M. Matrisian (2014). "Projecting cancer incidence and deaths to 2030: the unexpected burden of thyroid, liver, and pancreas cancers in the United States" Cancer Res 74(11): 2913-2921.
2. Encarnación-Rosado, J. and A. C. Kimmelman (2021). "Harnessing metabolic dependencies in pancreatic cancers." Nature Reviews Gastroenterology & Hepatology 18(7): 482-492.
3. Thomas, D. and P. Radhakrishnan (2019). "Tumor-stromal crosstalk in pancreatic cancer and tissue fibrosis." Molecular cancer 18: 1-15.
4. Chauhan, V. P., J. D. Martin, H. Liu, D. A. Lacorre, S. R. Jain, S. V. Kozin, T. Stylianopoulos, A. S. Mousa, X. Han, P. Adstamongkonkul, Z. Popović, P. Huang, M. G. Bawendi, Y. Boucher and R. K. Jain (2013). "Angiotensin inhibition enhances drug delivery and potentiates chemotherapy by decompressing tumour blood vessels." Nat Commun 4: 2516.
5. Pinter, M. and R. K. Jain (2017). "Targeting the renin-angiotensin system to improve cancer treatment: Implications for immunotherapy." Sci Transl Med 9(410).

Introduction

Pancreatic ductal adenocarcinoma (PDAC) is a highly metastatic disease refractory to all targeted and immune therapies. However, our understanding of PDAC microenvironment especially the metastatic microenvironment is very limited partly due to the inaccessibility to metastatic tumor tissues. Here, we aim to carry out the first single-cell transcriptome analysis of PDAC metastatic microenvironment in matched primary tumor and liver metastasis tissues.

Aims & Methods

We collected synchronously resected PDAC primary tumors and matched liver metastases from four PDAC patients and performed single-cell RNA sequencing. We performed comparative analysis on both cellular composition and functional phenotyping between primary and metastatic tumors. We also performed trajectory analysis and cellular interactome analysis in the metastasis microenvironment.

Results

Epithelial cancer cells exhibited distinct transcriptomic profile in liver metastasis with clearly defined evolutionary routes from primary tumor. We identified specific subtypes of stromal and immune cells critical to the formation of the pro-tumor microenvironment in metastatic lesions, including RGS5⁺ cancer-associated fibroblasts, CCL18⁺ lipid-associated macrophages, S100A8⁺ neutrophils and FOXP3⁺ regulatory T cells. We also identified several new biomarkers associated with PDAC metastasis and poor prognosis, such as LITAF, SPRR1B, KLK7 and LGALS9. Cellular interactome analysis further revealed that the lack of tumor-immune cell interaction in metastatic tissues contributes to the formation of the immunosuppressive microenvironment.

Conclusion

Our study provides a comprehensive characterization of the transcriptional landscape of PDAC liver metastasis, which deepens our understanding of the mechanisms underlying the immunosuppressive microenvironment in metastatic PDAC and serves as a valuable resource for the design of novel targeted therapies.

Disclosure

No