Effect of splenectomy on hepatic metastasis of colon carcinoma and natural killer activity in the liver

A Glimpse into the Role and Effectiveness of Splenectomy for Isolated Metachronous Spleen Metastasis of Colorectal Cancer Origin: Long-Term Survivals Can Be Achieved

Background: Many papers exploring the role of resectioning metastases in colorectal cancer (CRC) have focused mainly on liver and lung sites, showing improved survival compared with non-resectional therapies. However, data about exceptional metastatic sites such as splenic metastases (SMs) are scarce. This paper aims to assess the role and effectiveness of splenectomy in the case of isolated metachronous SM of CRC origin. Methods: The patients' data were extracted after a comprehensive literature search through public databases for articles reporting patients with splenectomies for isolated metachronous SM of CRC origin. Potential predictors of survival were explored, along with demographic, diagnostic, pathology, and treatment data for each patient. Results: A total of 83 patients with splenectomies for isolated metachronous SM of CRC origin were identified. The primary CRC was at an advanced stage (Duke's C-70.3%) and on the left colon (45.5%) for most patients, while the median interval between CRC resection and SM was 24 months. The median overall survival after splenectomy was 84 months, and patients younger than 62 years presented statistically significantly worse overall survival rates than those ≥62 years old (p = 0.011). There was no significant impact on the long-term outcomes for factors including primary tumor location or adjuvant chemotherapy (p values ≥ 0.070, ns). Laparoscopic splenectomy was increasingly used in the last 20 years from 2002 (33.3% vs. 0%, p < 0.001). Conclusions: Splenectomy is the optimal treatment for patients with isolated metachronous SM of CRC, with the laparoscopic approach being increasingly used and having the potential to become a standard of care. Encouraging long-term survival rates were reported in the context of a multidisciplinary approach. Younger ages are associated with worse survival. Perioperative chemotherapy in the context of a patient diagnosed with SM of CRC origin appears to be a reasonable option, although the present study failed to show any significant impact on long-term survival.

Splenectomy has opposite effects on the growth of primary compared with metastatic tumors in a murine colon cancer model

The spleen is a key source of circulating and tumor-infiltrating immune cells. However, the effect of splenectomy on tumor growth remains unclear. At 3 weeks after splenectomy, we subcutaneously injected LuM1 cells into BALB/c mice and evaluated the growth of primary tumors and lung metastases at 4 weeks after tumor inoculation. In addition, we examined the phenotypes of immune cells in peripheral blood by using flow cytometry and in tumor tissue by using multiplex immunohistochemistry. The growth of primary tumors was reduced in splenectomized mice compared with the sham-operated group. Conversely, splenectomized mice had more lung metastases. Splenectomized mice had fewer CD11b+cells, especially monocytic MDSCs (CD11b+Gr-1neg-lowLy6chigh), and NK cells (CD49b+CD335+). The proportion of NK cells was inversely correlated with the number of lung metastases. In splenectomized mice, the density of CD3+ and granzyme B+ CD8+ T cells was increased, with fewer M2-type macrophages in primary tumors, but NK cells were decreased markedly in lung. Splenectomy concurrently enhances T cell-mediated acquired immunity by reducing the number of monocytic MDSCs and suppresses innate immunity by decreasing the number of NK cells. Splenectomy has opposite effects on primary and metastatic lesions through differential regulation on these two immune systems.

Minimally Invasive Versus Open Pancreatectomy for Right-Sided and Left-Sided G1/G2 Nonfunctioning Pancreatic Neuroendocrine Tumors: A Multicenter Matched Analysis with an Inverse Probability of Treatment-Weighting Method

BACKGROUND

Limited evidence exists for the safety and oncologic efficacy of minimally invasive surgery (MIS) for nonfunctioning pancreatic neuroendocrine tumors (NF-PNETs) according to tumor location. This study aimed to compare the surgical outcomes of MIS and open surgery (OS) for right- or left-sided NF-PNETs.

METHODS

The study collected data on patients who underwent surgical resection (pancreatoduodenectomy, distal/total/central pancreatectomy, duodenum-preserving pancreas head resection, or enucleation) of a localized NF-PNET between January 2000 and July 2017 at 14 institutions. The inverse probability of treatment-weighting method with propensity scores was used for analysis.

RESULTS

The study enrolled 859 patients: 478 OS and 381 MIS patients. A matched analysis by tumor location showed no differences in resection margin, intraoperative blood loss, or complications between MIS and OS. However, MIS was associated with a longer operation time for right-sided tumors (393.3 vs 316.7 min; P < 0.001) and a shorter postoperative hospital stay for left-sided tumors (8.9 vs 12.9 days; P < 0.01). The MIS group was associated with significantly higher survival rates than the OS group for right- and left-sided tumors, but survival did not differ for the patients divided by tumor grade and location. Multivariable analysis showed that MIS did not affect survival for any tumor location.

CONCLUSION

The short-term outcomes offered by MIS were comparable with those of OS except for a longer operation time for right-sided NF-PNETs. The oncologic outcomes were not compromised by MIS regardless of tumor location or grade. These findings suggest that MIS can be performed safely for selected patients with localized NF-PNETs.

Epigenetic modification in 4T1 mouse breast cancer model by artificial light at night and melatonin - the role of DNA-methyltransferase

Currently, one of the most disputed hypotheses regarding breast cancer (BC) development is exposure to short wavelength artificial light at night (ALAN) as multiple studies suggest a possible link between them. This link is suggested to be mediated by nocturnal melatonin suppression that plays an integral role in circadian regulations including cell division. The objective of the research was to evaluate effects of 1 × 30 min/midnight ALAN (134 µ Wcm^-2, 460 nm) with or without nocturnal melatonin supplement on tumor development and epigenetic responses in 4T1 tumor-bearing BALB/c mice. Mice were monitored for body mass (W_b) and tumor volume for 3 weeks and thereafter urine samples were collected at regular intervals for determining daily rhythms of 6-sulfatoxymelatonin (6-SMT). Finally, mice were sacrificed and the tumor, lungs, liver, and spleen were excised for analyzing the total activity of DNA methyltransferases (DNMT) and global DNA methylation (GDM) levels. Mice exposed to ALAN significantly reduced 6-SMT levels and increased W_b, tumor volume, and lung metastasis compared with controls. These effects were diminished by melatonin. The DNMT activity and GDM levels showed tissue-specific response. The enzymatic activity and GDM levels were lower in tumor and liver and higher in spleen and lungs under ALAN compared with controls. Our results suggest that ALAN disrupts the melatonin rhythm and potentially leading to increased BC burden by affecting DNMT activity and GDM levels. These data may also be applicable to early detection and management of BC by monitoring melatonin and GDM levels as early biomarker of ALAN circadian disruption.

Prognoses of advanced esophago-gastric junction cancer may be modified by thoracotomy and splenectomy

Globally, the incidence of esophago-gastric junction (EGJ) cancer is rapidly increasing. However, the proposed strategies for the treatment of these types of cancer are so diverse that there is no established consensus on the optimal treatment. The aim of the present study was to identify independent prognostic factors to delineate the optimal strategies for the treatment of EGJ cancer. The medical records of 150 patients with EGJ cancer who underwent curative surgery at the Kitasato University were retrospectively reviewed. The median follow-up period was 48 months. The patients with tumors that were classified as post-treatment primary tumor stage 3 [(y)pT3] or higher had a 5-year disease-specific survival (DSS) rate of 53%, whereas those with tumors that were classified as (y)pT0-2 had a 5-year DSS rate of 90%. Therefore, prognostic analysis was restricted to those tumors that were designated (y)pT3 or higher. A multivariate Cox's proportional hazards model identified the following independent prognostic factors that negatively influenced the DSS: i) Presence of tumors classified as post-treatment regional lymph node stage 1-3 [(y)pN1-3] [hazard ratio (HR), 3.62; 95% confidence interval (CI), 1.39-12.36]; ii) not undergoing treatment with splenectomy (HR, 2.40; 95% CI, 1.15-5.15); and iii) undergoing treatment with thoracotomy (HR, 2.07; 95% CI, 1.02-4.23). In patients with (y)pN0 tumors, the DSS rate was significantly improved for those who underwent splenectomy than for those who did not (P=0.024). In patients with (y)pN1-3 tumors, the DSS rate was significantly worse for those who underwent thoracotomy compared with those who did not (P=0.004). Splenectomy and thoracotomy may critically affect prognosis in locally advanced EGJ cancer that are classified as (y)pN0 and (y)pN1-3, respectively. Surgical treatments require optimization in order to improve prognoses in advanced EGJ cancer.

Splenectomy is associated with an aggressive tumor growth pattern and altered host immunity in an orthotopic syngeneic murine pancreatic cancer model

The purpose of this study was to investigate whether splenectomy influences the tumor growth and metastatic pattern in an orthotopic syngeneic murine pancreatic cancer model. Murine pancreatic cancer cells (PAN02) were subcutaneously injected into the flanks of nude mice. A small tumor fragment (3 mm²), harvested from a subcutaneous tumor. was orthotopically implanted in the tail of the pancreas of C57/BL6 mice without splenectomy (control group, n=15) or with simultaneous splenectomy (splenectomy group, n=15). Tumor growth and metastatic patterns were analyzed by laparotomy at 21 days after surgery. No tumor growth was found in 5 mice (33.3%) of the control group and 1 mouse (6.7%) of the splenectomy group (p=0.169). Tumor volume was significantly larger in splenectomy group (p=0.013). Peritoneal seeding was more frequently observed in the splenectomy group (11 (73.3%) vs. 4 (26.7%), p=0.011). There were no differences in the number of liver and kidney metastasis between the two groups. The ratios of tumor-infiltrating CD4⁺ to FoxP3⁺ and CD8⁺ to FoxP3⁺ were significantly higher in the control group compared to the splenectomy group (8.2 ± 9.3 vs. 2.4 ± 1.5, p=0.046; 2.5 ± 1.4 vs. 1.5 ± 0.4, p=0.031, respectively). Splenectomy enhanced tumor growth and peritoneal seeding in an orthotopic syngeneic murine pancreatic cancer mouse model. The ramification of these results are discussed for pancreatic cancer treatment.

Splenectomy inhibits non-small cell lung cancer growth by modulating anti-tumor adaptive and innate immune response

It has been shown that inhibitors of the immune system reside in the spleen and inhibit the endogenous antitumor effects of the immune system. We hypothesized that splenectomy would inhibit the growth of relatively large non-small lung cancer (NSCLC) tumors by modulating the systemic inhibition of the immune system, and in particular Myeloid Derived Suppressor Cells (MDSC). The effect of splenectomy was evaluated in several murine lung cancer models. We found that splenectomy reduces tumor growth and the development of lung metastases, but only in advanced tumors. In immune-deficient NOD-SCID mice the effect of splenectomy on tumor growth and metastatic spread disappeared. Splenectomy significantly reduced the presence of MDSC, and especially monocytic-MDSC in the circulation and inside the tumor. Specific reduction of the CCR2+ subset of monocytic MDSC was demonstrated, and the importance of the CCL2-CCR2 axis was further shown by a marked reduction in CCL2 following splenectomy. These changes were followed by changes in the macrophages contents of the tumors to become more antitumorigenic, and by increased activation of CD8⁺ Cytotoxic T-cells (CTL). By MDSC depletion, and adoptive transfer of MDSCs, we demonstrated that the effect of splenectomy on tumor growth was substantially mediated by MDSC cells. We conclude that the spleen is an important contributor to tumor growth and metastases, and that splenectomy can blunt this effect by depletion of MDSC, changing the amount and characteristics of myeloid cells and enhancing activation of CTL.

Proposal for splenectomy-omitting radical distal pancreatectomy in well-selected left-sided pancreatic cancer: multicenter survey study

BACKGROUND

When distal pancreatectomy is carried out for left-sided pancreatic cancer, splenectomy is usually performed not only for margin-negative resection but also for effective clearance of the splenic hilar lymph nodes (LNs). However, the incidence of splenic hilar LN metastasis in these patients has not been definitively determined.

METHODS

From April 2010 to June 2011, in a pilot study, we analyzed the medical records of twelve patients who had undergone radical antegrade modular pancreatosplenectomy. Potential remnant soft tissue around the splenic hilum, which would be left following an extended Warshaw's procedure, was dissected and sent to a pathologist. Three Japanese medical centers conducted a retrospective survey of splenic hilar lymph node metastasis in left-sided pancreatic cancer to support our study.

RESULTS

In the pilot study, all twelve patients had adenocarcinoma with a median tumor size of 2 cm. Six patients had LN metastasis and a median number of 4 splenic hilar LNs were evaluated; however, no splenic hilar LN metastasis was noted. In the Japanese multicenter survey (n = 85), only four patients had splenic LN metastasis. Small (<3 cm) and proximal (neck/body) left-sided pancreatic cancer might not be associated with splenic hilar LN metastasis (P < 0.05).

CONCLUSIONS

In well-selected left-sided pancreatic cancer, the incidence of splenic hilar LN metastasis is low enough that splenectomy-omitting radical distal pancreatectomy would be feasible. The rationale for routine splenectomy should be re-evaluated, and the oncologic effects of the preserved spleen need to be investigated further.

Local targeted therapy of liver metastasis from colon cancer by galactosylated liposome encapsulated with doxorubicin

Since regional drug administration enables to maintain a high drug concentration within tumors, we compared the plasma concentration and biodistribution of doxorubicin (Dox) from drug-loaded conventional liposomes by local or systemic administration. The results demonstrated that drug concentration was substantially improved in liver as well as a decrease in blood and other organs by spleen injection mimicking portal vein perfusion (regional administration). To further investigate the targeted therapeutic effect of galactosylated liposome encapsulated doxorubicin (Dox) by regional administration, liver targeting liposomes were prepared by incorporating galactosylated-DPPE to conventional liposomes. Liposome uptake and targeting were verified in vitro and in vivo by fluorescence microscopy and xenogen IVIS imaging system, respectively. The results showed that galactose targeted liposomes presented a stronger specific cell uptake by human hepatocellular carcinoma HepG2 cells compared to the non-targeted liposomes. In vivo fluorescence imaging showed that the intra-hepatic deposition of conventional and galactosylated liposomes via spleen injection was more than that via tail vein administration, and galactosylated liposomes had higher fluorescent intensity over conventional liposomes in the liver post spleen administration. The anti-tumor effect of various drug administration routes for both liposomal formulations was evaluated using a murine liver metastasis model of colon cancer. The results indicated that tumor progression in the liver and mesenteric lymph nodes was significantly suppressed by Dox-loaded galactosylated liposomes via spleen injection, while no significance was observed in non-targeted formulations. Our data indicated that local perfusion of galactosylated liposomal doxorubicin had a great promise for the treatment of liver metastasis from colon cancer.

Monocytes control natural killer cell differentiation to effector phenotypes

Natural killer (NK) cells play a major role in immunologic surveillance of cancer. Whether NK-cell subsets have specific roles during antitumor responses and what the signals are that drive their terminal maturation remain unclear. Using an in vivo model of tumor immunity, we show here that CD11b(hi)CD27(low) NK cells migrate to the tumor site to reject major histocompatibility complex class I negative tumors, a response that is severely impaired in Txb21(-/-) mice. The phenotypical analysis of Txb21-deficient mice shows that, in the absence of Txb21, NK-cell differentiation is arrested specifically at the CD11b(hi)CD27(hi) stage, resulting in the complete absence of terminally differentiated CD11b(hi)CD27(low) NK cells. Adoptive transfer experiments and radiation bone marrow chimera reveal that a Txb21(+/+) environment rescues the CD11b(hi)CD27(hi) to CD11b(hi)CD27(low) transition of Txb21(-/-) NK cells. Furthermore, in vivo depletion of myeloid cells and in vitro coculture experiments demonstrate that spleen monocytes mediate the terminal differentiation of peripheral NK cells in a Txb21- and IL-15Rα-dependent manner. Together, these data reveal a novel, unrecognized role for Txb21 expression in monocytes in promoting NK-cell development and help appreciate how various NK-cell subsets are generated and participate in antitumor immunity.

Decreased Growth Rate of Lung Metastatic Lesions after Splenectomy in Mice

BACKGROUND

The effect of splenectomy on hematogenous metastases of malignant tumors remains controversial. The aim of this study was to clarify the effect of splenectomy on hematogenous metastases in an animal model.

METHODS

Colon 26 cancer cells were inoculated into the lateral tail vein of 90 mice. The mice were then assigned to a splenectomy group or a control group. Lung weight, number of lung metastases, size of metastatic nodules, and serum vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) levels after the surgical procedure were measured and compared between the two groups.

RESULTS

The lung nodules were significantly smaller in the splenectomy group than in the control group. In both groups, the serum VEGF levels increased on day 1 and then decreased. The serum VEGF levels on day 5 were significantly lower in the splenectomy group than in the control group. The serum bFGF levels were significantly lower in the splenectomy group than in the control group on days 1 and 5. Immunohistochemical study showed that bFGF was produced by reticuloendothelial cells of the spleen.

CONCLUSION

The growth rate of hematogenous metastatic lesions appears to decrease after splenectomy and may be associated with decreases in serum levels of VEGF and bFGF induced by splenectomy.

Antitumor effect of a splenic injection of 5-fluorouracil on metastatic liver cancer in mice

The regional administration of 5-fluorouracil (5-FU) has been the fundamental therapy against liver metastases for the improvement of patient prognosis; however, there have been few reports about the immunological effects of this agent. It is also unknown whether it affects the spleen, one of the major lymphoid organs. The objective of the present study was to determine the immunological effect of an intrasplenic injection of 5-FU against liver metastases. We investigated the effect of an intrasplenic injection of 5-FU on the formation of experimental liver metastasis resulting from an intraportal vein injection of colon 26 carcinoma cells in BALB/c mice and elucidated some of the underlying mechanisms involving the effects of this on cellular immunity. Liver metastases were significantly diminished by the splenic injection of 5-FU, particularly in comparison with the portal injection or systemic administration. This was followed by augmentation of the interleukin-12 (IL-12) level in the spleen and activation of hepatic mononuclear cells. In those cells, NK1.1+ (NKT) cells played a central role against metastases. A splenic injection of 5-FU is more effective on the involution of liver metastases than portal or systemic injection. This effect may be attributed to the augmentation of the IL-12 level in the spleen and of NKT cells in the liver rather than to the original effect of 5-FU, which is the so-called inhibition of DNA synthesis.

The Incidence of Splenectomy is Decreasing: Lessons Learned from Trauma Experience

Over the past decade, splenic preservation has become a well-reported and accepted principle in trauma management. The reasons for splenic preservation may have influenced nontraumatic surgical management as well. To investigate the changing incidence and indications for splenectomy, we conducted a 10-year review of all splenectomies at our institution. During this time, between January 1, 1986, and December 31, 1995, 896 patients underwent splenectomy. Hospital charts and records were examined to determine the etiology and incidence of splenectomy. Indications were classified as: 1) trauma, i.e., performed for blunt or penetrating injury; 2) hematologic malignancy, i.e., therapy or staging of underlying leukemia, Hodgkin's lymphoma, or non-Hodgkin's lymphoma; 3) cytopenia, i.e., treatment of thrombocytopenia, anemia, or leukopenia; 4) iatrogenic, i.e., injury during another procedure; 5) incidental, i.e., required for adjacent organ resection; 6) portal hypertension, i.e., left-sided portal hypertension or during shunting procedure; 7) diagnostic, i.e., uncertainty excluding hematologic malignancy; or 8) other, i.e., miscellaneous indications. Trauma accounted for 41.5 per cent of all splenectomies during this time period, hematologic malignancy 15.4 per cent, cytopenia 15.6 per cent, incidental 12.3 per cent, iatrogenic 8.1 per cent, portal hypertension 2.3 per cent, diagnostic 2.0 per cent, and other 2.7 per cent. Comparing the first and second 5-year time periods, the following increases/decreases in average annual incidence were noted: splenectomy for all indications, -36.9 per cent; trauma, -32.9 per cent; hematologic malignancy, -51.4 per cent; cytopenia, 35.1 per cent; incidental, -35.9 per cent; iatrogenic, -30.2 per cent; diagnostic, +4.9 per cent, and other, -57 per cent. Traumatic injury to the spleen remains the most common indication for splenectomy, but the incidence has decreased dramatically over the past 10 years. Splenectomies for treatment of hematologic malignancies and cytopenia, as well as incidental and iatrogenic splenectomies, have also decreased significantly. Only the incidence of diagnostic splenectomy has remained stable. Although initiated within the field of trauma, the advantages of splenic preservation now appear to be well recognized beyond that field.

Role of sialylglycoconjugate(s) in the initial phase of metastasis of liver-metastatic RAW117 lymphoma cells

To elucidate the early events of blood-borne metastasis under actual blood flow, real-time trafficking of RAW117 large cell lymphoma cells, namely parental RAW117-P and liver-metastatic RAW117-H10 cells, was investigated using positron emission tomography (PET). Both types of cells accumulated in the liver immediately after injection via the portal vein, and were eliminated from the liver time-dependently. The elimination rate of RAW117-H10 cells, however, was slower than that of RAW117-P cells, suggesting that RAW117-H10 cells interact more strongly with hepatic sinusoidal endothelium than the parental cells. This result correlated with the metastatic potential of these cells: RAW117-H10 cells metastasized in the liver to a greater extent than RAW117-P cells after injection via this route. To investigate the role of sialylglycoconjugates in the interaction of RAW117-H10 cells with the hepatic endothelium after injection via the portal vein, the trafficking of RAW117-H10 cells was examined after the cells had been treated with sialidase. The elimination rate of RAW117-H10 cells from liver was observed to be greatly accelerated by sialidase treatment. To elucidate what kind of sialylglycoconjugates is related to this phenomenon, we analyzed the distribution of sialyl Lewis A and sialyl Lewis X antigens of both sublines of RAW117 by using flow cytometry. RAW117-H10 cells were found to express a much higher level of sialyl Lewis A than RAW117-P cells, whereas the amount of sialyl Lewis X did not differ significantly. These findings suggest that some sialylglycoconjugates, perhaps sialyl Lewis A in particular, play an important role in the initial interaction of RAW117-H10 cells with the hepatic endothelium, leading to metastasis.

Gene therapy for hepatic micrometastasis of murine colon carcinoma

BACKGROUNDS/AIMS

Pit cells are located in the hepatic sinusoids and are organ-associated natural killer cells that contribute to immune surveillance in the liver. In the present study, the interleukin-2 gene was introduced into hepatocytes using an adenovirus vector to induce interleukin-2 production in an attempt to enhance the natural killer activity of pit cells, leading to inhibition of metastasis of colon carcinoma.

METHODS

The recombinant adenovirus vector "Adex1CAmIL2" was constructed by inserting an expression unit which was composed of the CAG promotor (cytomegalovirus enhancer plus chicken beta-actin promotor), murine interleukin-2 cDNA, and a rabbit beta-globin polyadenylation signal. After administration of Adex1CAmIL2 to mice (4x10(7) pfu per animal), the expression of murine interleukin-2 in hepatocytes was examined by immunostaining and in situ hybridization, and the natural killer activity of hepatic mononuclear cells was measured. Inhibition of hepatic metastasis of colon carcinoma was examined after infusion of colon 38 tumor cells into the superior mesenteric vein.

RESULTS

After administration of Adex1CAmIL2, interleukin-2 mRNA expression was demonstrated in hepatocytes until day 7, and the serum interleukin-2 level was increased. The natural killer activity of hepatic mononuclear cells was markedly enhanced for 7-10 days. Hepatic metastasis was inhibited by administration of Adex1CAmIL2 until day 7 after tumor cell inoculation.

CONCLUSION

These results suggest that gene therapy using Adex1CAmIL2 could be potentially useful for inhibiting hepatic micrometastasis by enhancing the natural killer activity of pit cells.