Splenectomy suppresses growth and metastasis of hepatocellular carcinoma through decreasing myeloid-derived suppressor cells in vivo

SAR131675, a VEGRF3 Inhibitor, Modulates the Immune Response and Reduces the Growth of Colorectal Cancer Liver Metastasis

Simple Summary

Colorectal cancer most often metastasizes to the liver, and in most cases, it is unresectable at diagnosis. New treatment options targeting specific cancer characteristics are needed and are currently being explored. Herein we looked at the use of a selective VEGFR-3 tyrosine kinase inhibitor, SAR131675, as an anti-tumor agent in a mouse model of colorectal liver metastasis. We found that SAR131675 dramatically reduced tumor growth and changed the immune response within the tumor and the surrounding liver, suggesting the use of SAR131675 as an adjuvant therapy for colorectal liver metastasis.

Abstract

Most patients with colorectal cancer (CRC) develop metastases, predominantly in the liver (CLM). Targeted therapies are being investigated to improve current CLM treatments. This study tested the effectiveness of SAR131675, a selective VEGFR-3 tyrosine kinase inhibitor, to inhibit CLM in a murine model. Following intrasplenic induction of CLM, mice were treated daily with SAR131675. Tumor growth and immune infiltrates into tumor and liver tissues were assessed at 10-, 16- and 22-days post tumor induction by stereology, IHC and flow cytometry. SAR151675 treatment significantly reduced tumor burden and F4/80⁺ macrophages in the liver tissues. Analysis of immune cell infiltrates in liver showed tissue that at day 22, had the proportion of CD45⁺ leukocytes significantly reduced, particularly myeloid cells. Analysis of myeloid cells (CD11b⁺ CD45⁺) indicated that the proportion of F4/80⁻ Ly6C^low was significantly reduced, including a predominate PD-L1⁺ subset, while CD3⁺ T cells increased, particularly CD8⁺ PD1⁺, reflected by an increase in the CD8⁺:CD4⁺ T cell ratio. In the tumor tissue SAR11675 treatment reduced the predominant population of F4/80⁺ Ly6C^lo and increased CD4⁺ T cells. These results suggest that SAR131675 alters the immune composition within tumor and the surrounding liver in the later stages of development, resulting in a less immunosuppressive environment. This immunomodulation effect may contribute to the suppression of tumor growth.

Oncologic outcomes after splenectomy during initial cytoreductive surgery in advanced epithelial ovarian cancer: a nationwide population-based cohort study

INTRODUCTION

Epithelial ovarian cancer (EOC) patients undergoing splenectomy during cytoreductive surgery represent a small subgroup of patients. Splenic metastases or technical reasons due to extensive upper abdominal disease may require a splenectomy. It has been hypothesized that as the spleen's antitumor immunologic functions may inhibit cancer growth, splenectomy may promote the growth of residual disease as observed in other cancer types of murine studies. The few studies assessing the impact of splenectomy on the oncologic outcomes of advanced stage EOC patients have reported inconsistent results. It remains unclear whether splenectomy during cytoreductive surgery is justified to achieve complete cytoreduction. The aim of this study was to assess the impact of a splenectomy on perioperative outcomes and survival of advanced stage EOC patients.

MATERIAL AND METHODS

In this nationwide population-based study, all consecutive patients diagnosed with FIGO stage IIIC and IV EOC between 1 January 2008 and 31 December 2015 were identified from the Netherlands Cancer Registry. Patients who underwent cytoreductive surgery combined with platinum-based chemotherapy as primary treatment were selected. Differences in clinicopathologic characteristics between splenectomy and non-splenectomy patients were assessed. Progression-free survival (PFS) and overall survival (OS) were analyzed using Kaplan-Meier survival curves and log-rank tests. Cox proportional hazards models were used to adjust for covariates that influence survival.

RESULTS

A total of 3911 patients were identified: 99 splenectomy and 3812 non-splenectomy patients. Splenectomy patients were more likely to undergo extensive surgery or surgical reintervention, to receive intraperitoneal chemotherapy, intraoperative and postoperative blood transfusion, to experience postoperative infections, and to be admitted to an intensive care unit (all p < 0.002). No significant differences in PFS or OS were observed between splenectomy versus non-splenectomy patients after adjusting for covariates.

CONCLUSIONS

Although advanced stage EOC patients who undergo splenectomy during cytoreductive surgery have less favorable perioperative outcomes, no adverse impact of splenectomy on the survival of advanced stage EOC patients was observed. Splenectomy during cytoreductive surgery seems to be justified to achieve complete cytoreduction in advanced stage EOC patients.

Tumor-Associated Macrophages-Implications for Molecular Oncology and Imaging

Tumor-associated macrophages (TAMs) represent the largest group of leukocytes within the tumor microenvironment (TME) of solid tumors and orchestrate the composition of anti- as well as pro-tumorigenic factors. This makes TAMs an excellent target for novel cancer therapies. The plasticity of TAMs resulting in varying membrane receptors and expression of intracellular proteins allow the specific characterization of different subsets of TAMs. Those markers similarly allow tracking of TAMs by different means of molecular imaging. This review aims to provides an overview of the origin of tumor-associated macrophages, their polarization in different subtypes, and how characteristic markers of the subtypes can be used as targets for molecular imaging and theranostic approaches.

Splenectomy before hepatectomy for patients with hepatocellular carcinoma and hypersplenism: A retrospective study

The spleen plays an important role in tumor progression and the curative effects of splenectomy before hepatectomy for hypersplenism and hepatocellular carcinoma (HCC) are not clear. We investigated whether splenectomy before hepatectomy increases survival rate among patients with HCC and hypersplenism compared with that of patients who underwent synchronous hepatectomy and splenectomy or hepatectomy alone.Between January 2011 and December 2016, 266 patients who underwent hepatectomy as a result of HCC and portal hypertension secondary to hepatitis were retrospectively analyzed. Their perioperative complications and survival outcome were evaluated.Patients underwent synchronous hepatectomy and splenectomy (H-S group) and underwent splenectomy before hepatectomy (H-preS group) exhibited significantly higher disease-free survival (DFS) rates than those of patients underwent hepatectomy alone (H-O group). The DFS rates for patients in the H-S group, H-preS group, and H-O group were 74.6%, 48.4%, 39.8%, and 80.1%, 54.2%, 40.1%, and 60.5%, 30.3%, 13.3%, at 1, 3, and 5 years after surgery, respectively. Tumor size, tumors number, and levels of alpha fetoprotein (AFP) were independent risk factors for DFS. Gender and tumor size were independent prognostic factor for overall survival (OS). The preoperative white blood cell (WBC) and platelet (PLT) counts were significantly higher in the H-preS group than in those of the H-S group and the H-O group. After operation, the WBC and PLT counts in the H-S group and H-preS groups were significantly higher compared to those of the H-O group.No matter splenectomy before hepatectomy or synchronous hepatectomy and splenectomy, hepatectomy with splenectomy may improve DFS rates in patients with HCC and hypersplenism, and splenectomy before hepatectomy alleviates hypersplenism without an increased surgical risk.

Immunological consequences following splenectomy in patients with liver cirrhosis

The immune status in patients with liver cirrhosis is generally impaired due to concomitant hypersplenism. As the spleen is the largest lymphoid organ, deleterious events resulting from splenectomy are of concern in these patients. However, the immunological consequences after splenectomy have not yet been fully elucidated. In the present study, the immune status after splenectomy was comprehensively examined. Splenectomy was performed in 11 patients with liver cirrhosis and hypersplenism, and the immune status in peripheral blood was examined and compared before and at 1, 3 and 6 months after splenectomy. Splenectomy significantly lowered the neutrophil-to-lymphocyte ratio, due to a surge in lymphocytes in the peripheral circulation at 3 and 6 months after splenectomy. The frequency of cluster of differentiation (CD)4⁺ T cells decreased after splenectomy, whereas the frequency of CD8⁺ T cells increased. Notably, the frequencies of the naïve and central memory subsets of CD4⁺ and CD8⁺ T cells decreased, whereas those of the effector memory subset trended upward. In addition, the frequencies of other immune cells such as γδ T cells, natural killer T cells and natural killer cells transiently increased, while inhibitory cells such as regulatory T cells and myeloid-derived suppressor cells significantly decreased. T-cell responses to viral- and tumor-associated antigens increased after splenectomy in five of eight and two of five patients, respectively. To the best of our knowledge, this is the first study to precisely examine the drastic changes of immunological phenotypes in peripheral blood after splenectomy in patients with cirrhosis. Our findings suggested that splenectomy in patients with cirrhosis may ameliorate the impaired immune status, possibly by reducing suppressive cells and enhancing the effector cell population and function, which could, at least in part, explain the mechanisms responsible for the clinical benefits of splenectomy.

Synchronous hepatectomy and splenectomy vs hepatectomy for selected patients with hepatocellular carcinoma and clinically significant portal hypertension: A systematic review and meta-analysis

 This review aimed to evaluate the safety, feasibility, and effectiveness of synchronous hepatectomy and splenectomy for selected patients with hepatocellular carcinoma and clinically significant portal hypertension compared to hepatectomy alone. A systematic search in electronic databases was conducted. A total of 8 studies including 1445 patients were reviewed. While perioperative safety was satisfactory, synchronous hepatectomy and splenectomy were associated with a significant improvement of 5-year overall survival (odds ratio = 1.81; 95% confidence interval: 1.35, 2.42; P < 0.0001).

Improved survival following splenectomy combined with curative treatments for hepatocellular carcinoma in Child B patients: A propensity score matching study

AIMS

To explore the benefits of curative treatments (liver resection or local ablation) combined with splenectomy for patients with hepatocellular carcinoma (HCC) and Child grade B liver function.

METHODS

We reviewed 245 patients with Child grade B liver function who underwent treatment with curative intent for HCC. Among these patients, 116 patients underwent curative treatment combined with splenectomy (the splenectomy group); the other 129 patients only underwent curative treatment (the non-splenectomy group). A one-to-one matching produced 95 paired patients, perioperative and oncological outcomes were compared, and liver function changes were reassessed 1 year later.

RESULTS

The perioperative liver failure rates were 7.4% and 6.3% (P = 1.000) and the 90-day mortality was 4.2% and 6.3% (P = 0.747) in the splenectomy group and non-splenectomy group, respectively. The 1-, 3-, and 5-year overall survival rates were remarkably greater in the splenectomy group than in the non-splenectomy group (92.6% vs. 79.8%, 53.4% vs. 34.7%, and 19.9% vs. 11.0%, respectively; P = 0.004). In the univariate and multivariate analyses, splenectomy was identified as a protective factor for long-term survival. The proportion of patients whose liver function improved to Child A 1 year after surgery was also higher in the splenectomy group than in the non-splenectomy group (95.4% vs. 83.3%; P = 0.048).

CONCLUSIONS

Compared with non-splenectomy, curative treatments combined with splenectomy for patients with HCC and Child B grade liver function showed no different perioperative outcomes but achieved significant survival benefit. Splenectomy is a beneficial factor for patients with HCC and Child B liver function; liver function improved significantly 1 year after splenectomy.