Abstract 5136: Surgical stress promotes long-lasting protumorigenic changes in bone marrow derived progenitor cells

Introduction: Surgery is a crucial intervention for cancer patients. However, the perioperative period is characterized by an increased risk for accelerated growth of metastatic disease. Our recent work shows that the protumorigenic systemic inflammatory changes and the formation of neutrophil extracellular traps (NETs) persist months after surgery in both mice and humans, and parallel micrometastatic tumor growth and recurrence. Here we hypothesized that surgery may induce long-term sustained epigenetic and transcriptomic changes in bone marrow derived granulocytes-monocytes progenitor cells (GMPs) leading to functional reprogramming of mature neutrophils and persistent systemic release of these protumorigenic NET-forming neutrophils.

Methods: Eight-week-old mice were subjected to non-lethal surgical stress (laparotomy) for 30 mins. Seven days after, mice were inoculated with 1x106 MC38 (murine colorectal cancer cells) subcutaneously. For bone marrow (BM) transplant model, a group of B6 congenic (CD45.1) mice were subjected to laparotomy. BM derived cells were harvested 7 days after the procedure and orthotopically transplanted into B6 CD45.2 irradiated (1000 rads) mice. After the establishment of hematopoiesis (6 weeks), MC38 cancer cells were implanted into the recipient mice.

Results: Mice that underwent laparotomy had significantly increased tumor volume at 3 weeks compared to control mice, that only underwent anesthesia (Laparotomy vs control **p<0.01). While the intratumoral flowcytometry analysis showed no difference in the frequency of infiltrating immune cells, quantitative (q) PCR analysis revealed significant plasticity in the tumor infiltrating neutrophils (TANs) observed by an increase in the expression of genes (MCP1, Arg1) associated with pro-inflammatory (N2) type neutrophils compared to control. A persistent increased level of NETs was also observed within the tumors and circulation of mice several weeks after laparotomy. ATAC-seq and Bulk-RNA-seq analysis further revealed major epigenetic and transcriptomic changes in TANs, circulating neutrophils and GMPs. To substantiate long-lasting surgical effects, tumor burden was assessed in the BM recipient mice and showed to be significantly increased in mice that had received BM cells from laparotomy mice versus BM cells from sham group.

Conclusion: Surgery promotes long-term rewiring of the bone marrow derived cells resulting in increased tumor growth. Understanding the underlying molecular mechanism may help with therapeutic interventions to prevent protumorigenic surgical effects and improve patient outcomes.

Citation Format: Hamza O. Yazdani, Tony Haykal, Ruiqi Yang, Celine Tohme, David A. Geller, Samer Tohme. Surgical stress promotes long-lasting protumorigenic changes in bone marrow derived progenitor cells. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5136.

[Aneurysm of the hepatic artery treated by embolization]

The hepatic artery aneurysm represent 16 to 20% of visceral artery aneurysms. The man of 40 years of age is often affected. This aneurysm is often asymptomatic. The rupture menace its evolution and justify the treatment. Echo-doppler-color constitute a non invasive exam of choice for diagnosis. Embolisation has a more extent indications. A case is reported of an aneurysm of the hepatic artery treated with embolisation with review of the literature.

Exercise Preconditioning of the Donor Liver Decreases Cold Ischemia/Reperfusion Injury in a Mouse Model

BACKGROUND

Liver transplantation stands as the primary treatment for end-stage liver disease, with demand surging in recent decades because of expanded indications. However, hepatic ischemia/reperfusion injury can lead to liver transplant failure in both deceased donor and living donor transplantation. This study explored whether preconditioning donor livers through exercise training (ExT) could mitigate cold ischemic injury posttransplantation.

METHODS

Donor C57BL/6 mice underwent ExT via treadmill running or remained sedentary. After 4 wk, the donor liver underwent cold storage and subsequent orthotopic liver transplantation or ex vivo warm reperfusion.

RESULTS

Donor liver from mice subjected to ExT showed significantly decreased hepatic injury on reperfusion. Tissue histology revealed decreased sinusoidal congestion, vacuolization, and hepatocellular necrosis in livers from ExT mice, and immunofluorescence staining further revealed a decreased number of apoptotic cells in ExT grafts. Livers from ExT donors expressed decreased intragraft inflammatory cytokines cascade, decreased neutrophil infiltration and neutrophil extracellular traps, and increased M2 phenotype of recipient macrophages compared with grafts from sedentary mice. After cold storage, liver grafts from ExT donors showed decreased accumulation of reactive oxygen species and decreased levels of cytochrome c and high mobility group box 1 released in the liver effluent. In addition, ExT grafts showed upregulated peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and higher levels of mitochondrial content. Similar effects of decreased hepatic injury were observed in wild-type mice when pretreated with a PGC-1α stimulator ZLN005 instead of ExT.

CONCLUSIONS

These findings suggest that augmenting hepatocytic mitochondrial content through donor exercise or PGC-1α stimulation may offer therapeutic avenues to mitigate postreperfusion inflammation and improve transplant outcomes.

ZLN005, a PGC-1α Activator, Protects the Liver against Ischemia-Reperfusion Injury and the Progression of Hepatic Metastases

BACKGROUND

Exercise can promote sustainable protection against cold and warm liver ischemia-reperfusion injury (IRI) and tumor metastases. We have shown that this protection is by the induction of hepatic mitochondrial biogenesis pathway. In this study, we hypothesize that ZLN005, a PGC-1α activator, can be utilized as an alternative therapeutic strategy.

METHODS

Eight-week-old mice were pretreated with ZLN005 and subjected to liver warm IRI. To establish a liver metastatic model, MC38 cancer cells (1 × 106) were injected into the spleen, followed by splenectomy and liver IRI.

RESULTS

ZLN005-pretreated mice showed a significant decrease in IRI-induced tissue injury as measured by serum ALT/AST/LDH levels and tissue necrosis. ZLN005 pretreatment decreased ROS generation and cell apoptosis at the site of injury, with a significant decrease in serum pro-inflammatory cytokines, innate immune cells infiltration, and intrahepatic neutrophil extracellular trap (NET) formation. Moreover, mitochondrial mass was significantly upregulated in hepatocytes and maintained after IRI. This was confirmed in murine and human hepatocytes treated with ZLN005 in vitro under normoxic and hypoxic conditions. Additionally, ZLN005 preconditioning significantly attenuated tumor burden and increased the percentage of intratumoral cytotoxic T cells.

CONCLUSIONS

Our study highlights the effective protection of ZLN005 pretreatment as a therapeutic alternative in terms of acute liver injury and tumor metastases.

[Unusual metastases of breast cancer]

The breast cancer is the common cancer in female. The metastasis may occur any where in the body. The common sites are in the lymph nodes, the bones, the chest, the liver and the brain. Other sites of metastasis have little importance, rarely researched and constitute the objective of this article.

Abstract 1317: Exercise training prevents exosome mediated pre-metastatic niche formation in the liver

Introduction: Primary tumor cells release exosomes facilitating pre-metastatic niche formation in distant organs, initiating the process of metastasis. As metastasis is the main prognostic factor for patients, it is essential to understand the pre-metastatic niches and develop therapies to target them. It has been shown that Kupffer cells play an crucial role in the formation of pre-metastatic niche in the liver. We have recently shown that exercise training (ExT) alters the phenotype of Kupffer cells and attenuates tumor metastasis after surgery. Here, we hypothesize that ExT can interfere with exosome mediated pre-metastatic niches, hence decreasing metastasis.

Methods: Eight-week-old male mice were randomized into sedentary and ExT group. Mice were pre-educated with cancer exosomes for 4 weeks to induce pre-metastatic niche and intra-splenically injected with murine colorectal cancer (MC38) cells. Tumor metastasis and growth was followed by 3 weeks.

Results: Compared to the sedentary group, there was a significant decrease in metastatic nodules and hepatic tumor replacement in the ExT mice liver. To further study the effects of ExT, livers from both groups were harvested 4 weeks after exosome pre-education. We observed decrease in the uptake of tumor exosome, immune cells infiltration and fibronectin deposition in the ExT livers, which demonstrates less pre-metastatic niche formation. Bulk RNA sequencing was performed on Kupffer cells isolated from both groups. Ingenuity pathway analysis shows that Triggering Receptor Expressed on Myeloid cells 1 (TREM1) signaling pathway was downregulated in EXT group, indicating less activation of Kupffer cells.

Conclusions: These results indicate that exercise reduces pre-metastatic niche formation and tumor metastasis by affecting the interaction between cancer exosomes and Kupffer cells. In light of these findings, potential may exist to reduce exosome-induced liver pre-metastatic niches through the use of ExT as a nonpharmacologic therapy in patients with cancer.

Citation Format: Ruiqi Yang, Tony Haykal, Celine Tohme, Ronghua Wang, Christof Kaltenmeier, David Geller, Hamza Yazdani, Samer Tohme. Exercise training prevents exosome mediated pre-metastatic niche formation in the liver [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1317.

Abstract 5129: Neutrophil extracellular traps induced by surgical stress regulate cancer metabolism leading to tumor growth

Introduction:

Surgery is a crucial intervention to cure malignancies. However, evidence shows that the surgical insult and its accompanying immune response can enhance tumor growth and metastasis. Neutrophil Extracellular Traps (NETs) released systemically during surgical stress were previously shown to contribute to this process. In fact, to generate increased energy demands required for growth and metastasis, cancer cells in a stressful microenvironment need an adaptive mechanism where metabolic reprogramming to fatty acid (FA) oxidation has been emerging as an important process. Here, we aim to explore the direct effects of surgical NETs in regulating cancer cell metabolism leading to tumor growth and metastasis.

Methods:

For the indolent tumor model, C57BL/6 mice were injected with a small number of LLC-1 (Lewis Lung Cancer-1) cells subcutaneously (SQ) and a group was subjected to laparotomy for 30 mins, with or without intraperitoneal DNAse (NET inhibitor) injection perioperatively. Tumor growth was then followed for 4 weeks. For the tumor metastasis model, LLC-1 cells were injected SQ and allowed to grow for 3 weeks before resection with or without perioperative DNAse. Tumor metastasis to the lungs was assessed after 3 weeks. In vitro experiments on LLC-1 and MC-38 (murine colon adenocarcinoma) cancer cells were performed using NETs released from neutrophils freshly isolated from mice bone marrow and stimulated with Phorbol myristate acetate (PMA).

Results:

For the indolent tumor model, injection of cancer cells did not lead to any significant tumor growth after 4 weeks unless mice underwent surgical stress via laparotomy. Treatment with DNAse significantly reversed their growth. For the tumor metastasis model, tumor resection alone led to significant lung metastasis, but DNAse treatment during resection or resection in PAD-4 KO mice (unable to form NETs) led to significantly less metastatic burden. Furthermore, in vitro treatment of cancer cells with NETs lead to significant cell proliferation, relatively more under hypoxic and serum conditions. This was paralleled with a significant increase in fluorescently labeled FA uptake into cancer cells as detected by flow cytometry, as well as a significant upregulation of gene expression of FA transport proteins and oxidation enzymes.

Conclusion:

Surgical stress can promote tumor growth and metastasis through cancer cell metabolic reprogramming induced by systemically released NETs. We hope that elucidating the molecular mechanism behind this process can help in finding therapeutics to prevent the protumorigenic effects of surgical stress.

Citation Format: Tony Haykal, Ruiqi Yang, Celine Tohme, Ronghua Wang, David Geller, Christof Kaltenmeier, Hamza Yazdani, Samer Tohme. Neutrophil extracellular traps induced by surgical stress regulate cancer metabolism leading to tumor growth. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5129.