Pharyngeal carcinoma and natural killer cell activity

Transcription Factor E2F7 Hampers the Killing Effect of NK Cells against Colorectal Cancer Cells via Activating RAD18 Transcription

As a pivotal defensive line against multitudinous malignant tumors, natural killer (NK) cells exist in the tumor microenvironment (TME). RAD18 E3 Ubiquitin Protein Ligase (RAD18) has been reported to foster the malignant progression of multiple cancers, but its effect on NK function has not been mined. Here, the study was designed to mine the mechanism by which RAD18 regulates the killing effect of NK cells on colorectal cancer (CRC) cells. Expression of E2F Transcription Factor 7 (E2F7) and RAD18 in CRC tissues, their correlation, binding sites, and RAD18 enrichment pathway were analyzed by bioinformatics. Expression of E2F7 and RAD18 in cells was assayed by qRT-PCR and western blot. Dual-luciferase assay and chromatin immunoprecipitation (ChIP) assay verified the regulatory relationship between E2F7 and RAD18. CCK-8 assay was utilized to assay cell viability, colony formation assay to detect cell proliferation, lactate dehydrogenase (LDH) test to assay NK cell cytotoxicity, ELISA to assay levels of granulocyte-macrophage colony-stimulating factor (GM-CSF), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), and immunofluorescence to detect expression of toxic molecules perforin and granzyme B. High expression of RAD18 and E2F7 was found in CRC tissues and cells. Silencing RAD18 could hamper the proliferation of CRC cells, foster viability and cytotoxicity of NK cells, and increase the secretion of GM-CSF, TNF-α, IFN-γ as well as the expression of perforin and granzyme B. Additionally, ChIP and dual-luciferase reporter assay ascertained the binding relationship between RAD18 promoter region and E2F7. E2F7 could activate the transcription of RAD18, and silencing RAD18 reversed the inhibitory effect of E2F7 overexpression on NK cell killing. This work clarified the inhibitory effect of the E2F7/RAD18 axis on NK cell killing in CRC, and proffered a new direction for immunotherapy of CRC in targeted immune microenvironment.

Effector and cytolytic function of natural killer cells in anticancer immunity

Adaptive immune cells play an important role in mounting antigen-specific antitumor immunity. The contribution of innate immune cells such as monocytes, macrophages, natural killer (NK) cells, dendritic cells, and gamma-delta T cells is well studied in cancer immunology. NK cells are innate lymphoid cells that show effector and regulatory function in a contact-dependent and contact-independent manner. The cytotoxic function of NK cells plays an important role in killing the infected and transformed host cells and controlling infection and tumor growth. However, several studies have also ascribed the role of NK cells in inducing pathophysiology in autoimmune diseases, promoting immune tolerance in the uterus, and antitumor function in the tumor microenvironment. We discuss the fundamentals of NK cell biology, its distribution in different organs, cellular and molecular interactions, and its cytotoxic and noncytotoxic functions in cancer biology. We also highlight the use of NK cell-based adoptive cellular therapy in cancer.

Harnessing NK Cells to Control Metastasis

In recent years, tumor immunotherapy has produced remarkable results in tumor treatment. Nevertheless, its effects are severely limited in patients with low or absent pre-existing T cell immunity. Accordingly, metastasis remains the major cause of tumor-associated death. On the other hand, natural killer (NK) cells have the unique ability to recognize and rapidly act against tumor cells and surveil tumor cell dissemination. The role of NK cells in metastasis prevention is undisputable as an increase in the number of these cells mostly leads to a favorable prognosis. Hence, it is reasonable to consider that successful metastasis involves evasion of NK-cell-mediated immunosurveillance. Therefore, harnessing NK cells to control metastasis is promising. Circulating tumor cells (CTCs) are the seeds for distant metastasis, and the number of CTCs detected in the blood of patients with tumor is associated with a worse prognosis, whereas NK cells can eliminate highly motile CTCs especially in the blood. Here, we review the role of NK cells during metastasis, particularly the specific interactions of NK cells with CTCs, which may provide essential clues on how to harness the power of NK cells against tumor metastasis. As a result, a new way to prevent or treat metastatic tumor may be developed.

Innate Immune Checkpoint Inhibitors: The Next Breakthrough in Medical Oncology?

While immunotherapy has revolutionized the treatment of many types of advanced cancer, most patients still do not derive benefit. The currently available immune checkpoint inhibitors target the adaptive immune system, generating a T-cell antitumor response. However, an antitumor immune response depends on a complex interplay of both innate and adaptive immune cells. The innate immune system is a promising new target, and innate immune checkpoint inhibitors can disrupt inhibitory interactions ("don't eat me" signals) between tumor and both phagocytes and natural killer cells. The checkpoint inhibitor may also provide a stimulatory interaction ("eat me" signal), or this can be achieved through use of combination therapy. This generates antitumor effector functions including phagocytosis, natural cytotoxicity, antibody-dependent effects, and synergistic activation of the adaptive immune system via antigen presentation. This is a rapidly expanding area of drug development, either alone or in combination (with anticancer antibodies or adaptive immune checkpoint inhibitors). Here, we comprehensively review the mechanism of action and up-to-date solid tumor clinical trial data of the drugs targeting phagocytosis checkpoints (SIRPα/CD47, LILRB1/MHC-I, and LILRB2/MHC-I) and natural killer-cell checkpoints (TIGIT/CD112 + CD155, PVRIG/CD112, KIRs/MHC-I, and NKG2A-CD94/HLA-E). Innate immune checkpoint inhibitors could once again revolutionize immune-based cancer therapies.

NK cells adjuvant therapy shows survival benefits in a gastric mixed signet ring cell carcinoma patient: A case report

RATIONALE

Advanced signet ring cell (SRC) carcinoma has a worse prognosis. Therefore, early diagnosis and prevention is particularly important; SRC tumors have lower R0 resection rate and are thought to be less chemosensitive than non-SRCC. Consequently, a novel postoperative adjuvant treatment is urgently needed to improve clinical outcomes.

PATIENT CONCERNS

A 41-year-old female with advanced gastric SRC carcinoma was treated with radical gastrectomy and oxaliplatin-based regimen for 6 cycles after surgery. She was suspected of recurrence with the high level of carbohydrate antigen (CA) 72-4.

DIAGNOSES

The gastroscopy revealed SRC carcinoma of gastric antrum and poorly differentiated adenocarcinoma in some areas. The diagnosis of postoperative pathology report was gastric cancer with stage III C (T4a, N3a, M0).

INTERVENTIONS

The level of CA72-4 rapidly increased during the 2 follow-up after the completion of conventional treatment, ex vivo-cultured allogeneic natural killer (NK) cell infusion was offered to prevent recurrence.

OUTCOMES

Intravenous injections of NK cells combination with surgical treatment and chemotherapy showed therapeutic effects in this patient with possible relapse. The patient remained disease-free 46 months after the infusion of NK cells until the latest follow-up.

LESSONS

CA72-4 appeared to be the most sensitive and specific marker in the gastric cancer patient, and the high level of CA72-4 may indicate the risk of recurrence. This case report provide rationale for NK cell infusion following the rapid increase of CA72-4 to prevent recurrence.

Killers 2.0: NK cell therapies at the forefront of cancer control

Natural killer (NK) cells are innate cytotoxic lymphocytes involved in the surveillance and elimination of cancer. As we have learned more and more about the mechanisms NK cells employ to recognize and eliminate tumor cells, and how, in turn, cancer evades NK cell responses, we have gained a clear appreciation that NK cells can be harnessed in cancer immunotherapy. Here, we review the evidence for NK cells' critical role in combating transformed and malignant cells, and how cancer immunotherapies potentiate NK cell responses for therapeutic purposes. We highlight cutting-edge immunotherapeutic strategies in preclinical and clinical development such as adoptive NK cell transfer, chimeric antigen receptor-expressing NK cells (CAR-NKs), bispecific and trispecific killer cell engagers (BiKEs and TriKEs), checkpoint blockade, and oncolytic virotherapy. Further, we describe the challenges that NK cells face (e.g., postsurgical dysfunction) that must be overcome by these therapeutic modalities to achieve cancer clearance.

Progression or suppression: Two sides of the innate lymphoid cells in cancer

Innate lymphoid cells (ILCs) as key players in innate immunity have been shown to be significantly associated with inflammation, lymphoid neogenesis, tissue remodeling, mucosal immunity and lately have been considered a remarkable nominee for either tumor-promoting or tumor-inhibiting functions. This dual role of ILCs, which is driven by intrinsic and extrinsic factors like plasticity of ILCs and the tumor microenvironment, respectively, has aroused interest in ILCs subsets in past decade. So far, numerous studies in the cancer field have revealed ILCs to be key players in the initiation, progression and inhibition of tumors, therefore providing valuable insights into therapeutic approaches to utilize the immune system against cancer. Herein, the most recent achievements regarding ILCs subsets including new classifications, their transcription factors, markers, cytokine release and mechanisms that led to either progression or inhibition of many tumors have been evaluated. Additionally, the available data regarding ILCs in most prevalent cancers and new therapeutic approaches are summarized.

Membrane bound IL-21 based NK cell feeder cells drive robust expansion and metabolic activation of NK cells

NK cell adoptive therapy is a promising cancer therapeutic approach, but there are significant challenges that limiting its feasibility and clinical efficacy. One difficulty is the paucity of clinical grade manufacturing platforms to support the large scale expansion of highly active NK cells. We created an NK cell feeder cell line termed 'NKF' through overexpressing membrane bound IL-21 that is capable of inducing robust and sustained proliferation (>10,000-fold expansion at 5 weeks) of highly cytotoxic NK cells. The expanded NK cells exhibit increased cytotoxic function against a panel of blood cancer and solid tumor cells as compared to IL-2-activated non-expanded NK cells. The NKF-expanded NK cells also demonstrate efficacy in mouse models of human sarcoma and T cell leukemia. Mechanistic studies revealed that membrane-bound IL-21 leads to an activation of a STAT3/c-Myc pathway and increased NK cell metabolism with a shift towards aerobic glycolysis. The NKF feeder cell line is a promising new platform that enables the large scale proliferation of highly active NK cells in support of large scale third party NK cell clinical studies that have been recently intiatied. These results also provide mechanistic insights into how membrane-bound IL-21 regulates NK cell expansion.

Natural killer cells and other innate lymphoid cells in cancer

Immuno-oncology is an emerging field that has revolutionized cancer treatment. Most immunomodulatory strategies focus on enhancing T cell responses, but there has been a recent surge of interest in harnessing the relatively underexplored natural killer (NK) cell compartment for therapeutic interventions. NK cells show cytotoxic activity against diverse tumour cell types, and some of the clinical approaches originally developed to increase T cell cytotoxicity may also activate NK cells. Moreover, increasing numbers of studies have identified novel methods for increasing NK cell antitumour immunity and expanding NK cell populations ex vivo, thereby paving the way for a new generation of anticancer immunotherapies. The role of other innate lymphoid cells (group 1 innate lymphoid cell (ILC1), ILC2 and ILC3 subsets) in tumours is also being actively explored. This Review provides an overview of the field and summarizes current immunotherapeutic approaches for solid tumours and haematological malignancies.

Multifunctional Natural Killer Cell Engagers Targeting NKp46 Trigger Protective Tumor Immunity

Over the last decade, various new therapies have been developed to promote anti-tumor immunity. Despite interesting clinical results in hematological malignancies, the development of bispecific killer-cell-engager antibody formats directed against tumor cells and stimulating anti-tumor T cell immunity has proved challenging, mostly due to toxicity problems. We report here the generation of trifunctional natural killer (NK) cell engagers (NKCEs), targeting two activating receptors, NKp46 and CD16, on NK cells and a tumor antigen on cancer cells. Trifunctional NKCEs were more potent in vitro than clinical therapeutic antibodies targeting the same tumor antigen. They had similar in vivo pharmacokinetics to full IgG antibodies and no off-target effects and efficiently controlled tumor growth in mouse models of solid and invasive tumors. Trifunctional NKCEs thus constitute a new generation of molecules for fighting cancer. VIDEO ABSTRACT.

NK Cell-Based Immunotherapy in Cancer Metastasis

Metastasis represents the leading cause of cancer-related death mainly owing to the limited efficacy of current anticancer therapies on advanced malignancies. Although immunotherapy is rendering promising results in the treatment of cancer, many adverse events and factors hampering therapeutic efficacy, especially in solid tumors and metastases, still need to be solved. Moreover, immunotherapeutic strategies have mainly focused on modulating the activity of T cells, while Natural Killer (NK) cells have only recently been taken into consideration. NK cells represent an attractive target for cancer immunotherapy owing to their innate capacity to eliminate malignant tumors in a non-Major Histocompatibility Complex (MHC) and non-tumor antigen-restricted manner. In this review, we analyze the mechanisms and efficacy of NK cells in the control of metastasis and we detail the immunosubversive strategies developed by metastatic cells to evade NK cell-mediated immunosurveillance. We also share current and cutting-edge clinical approaches aimed at unleashing the full anti-metastatic potential of NK cells, including the adoptive transfer of NK cells, boosting of NK cell activity, redirecting NK cell activity against metastatic cells and the release of evasion mechanisms dampening NK cell immunosurveillance.

Cancer Recurrence and Regional Anesthesia: The Theories, the Data, and the Future in Outcomes

OBJECTIVE

More than one million people each year in the United States are diagnosed with cancer. Surgery is considered curative, but the perioperative phase represents a vulnerable period for residual disease to spread. Regional anesthesia has been proposed to reduce the incidence of recurrence by attenuating the sympathetic nervous system's response during surgery, reducing opioid requirements thus diminishing their immunosuppressant effects, and providing antitumor and anti-inflammatory effects directly through systemic local anesthetic action. In this article, we present a description of the perioperative period, a summary of the proposed hypotheses and available literature on the effects of regional anesthesia on cancer recurrence, and put regional anesthesia in context in regard to its potential role in reducing cancer recurrence during the perioperative period.

METHODS

A literature review was conducted through PubMed by examining the following topics: effects of surgery on tumor progression, roles of multiple perioperative variables (analgesics, hypothermia, blood transfusion, beta-blockade) in cancer recurrence, and available in vitro, animal, and human studies regarding the effects of regional anesthesia on cancer recurrence.

RESULTS

in vitro, animal and human retrospective studies suppport the hypothesis that in certain types of cancer, regional anesthesia may be associated with lower recurrence rates. A few well-planned human randomized clinical trials are currently under way that may provide more solid evidence to substantiate or refute the benefits of regional anesthesia in reducing cancer recurrence.

CONCLUSIONS

The benefits of regional anesthesia in reducing cancer recurrence have a sound theoretical basis and, in certain cancers, are supported by the existing body of literature. This article outlines the current state of our knowledge on the relationship between cancer progression and regional analgesia.

Decreased NK cells in patients with head and neck cancer determined in archival DNA

PURPOSE

Natural killer (NK) cells are a key element of the innate immune system implicated in human cancer. To examine NK cell levels in archived bloods from a study of human head and neck squamous cell carcinoma (HNSCC), a new DNA-based quantification method was developed.

EXPERIMENTAL DESIGN

NK cell-specific DNA methylation was identified by analyzing DNA methylation and mRNA array data from purified blood leukocyte subtypes (NK, T, B, monocytes, granulocytes), and confirmed via pyrosequencing and quantitative methylation specific PCR (qMSP). NK cell levels in archived whole blood DNA from 122 HNSCC patients and 122 controls were assessed by qMSP.

RESULTS

Pyrosequencing and qMSP confirmed that a demethylated DNA region in NKp46 distinguishes NK cells from other leukocytes, and serves as a quantitative NK cell marker. Demethylation of NKp46 was significantly lower in HNSCC patient bloods compared with controls (P < 0.001). Individuals in the lowest NK tertile had over 5-fold risk of being a HNSCC case, controlling for age, gender, HPV16 status, cigarette smoking, alcohol consumption, and BMI (OR = 5.6, 95% CI, 2.0 to 17.4). Cases did not show differences in NKp46 demethylation based on tumor site or stage.

CONCLUSIONS

The results of this study indicate a significant depression in NK cells in HNSCC patients that is unrelated to exposures associated with the disease. DNA methylation biomarkers of NK cells represent an alternative to conventional flow cytometry that can be applied in a wide variety of clinical and epidemiologic settings including archival blood specimens.

Depression, Immunity, and Survival in Patients With Hepatobiliary Carcinoma

Purpose

The aims of the present study were to assess the prevalence of depressive symptoms at diagnosis, test the association between depressive symptoms and survival, and preliminarily test a mediational model of depression, immunity, and survival in patients with hepatobiliary carcinoma (HBC).

Patients and Methods

One hundred one patients diagnosed with HBC were prospectively studied. Depressive symptoms were measured at diagnosis using the Center for Epidemiological Studies Depression Scale (CES-D). Sociodemographic and disease-specific data were gathered from the patients' charts. In a subsample of patients, stress; alcohol, tobacco, and drug use; sleep quality; physical activity; social support; natural killer (NK) cell number and cytotoxicity; and plasma levels of interleukin (IL) -4, IL-5, tumor necrosis factor alpha, and interferon gamma were measured. Survival was measured from date of diagnosis to death.

Results

At diagnosis, 37% of patients reported a CES-D score of ≥ 16 (clinical range). Using Cox regression analysis, sociodemographic and disease-specific variables and CES-D score significantly predicted survival (Breslow χ2= 32.4, P = .006). Only vascular invasion (P = .001) and CES-D score ≥ 16 (P = .03) were significant predictors. In a subsample of 23 patients, patients who reported a CES-D score of ≥ 16 were found to have significantly lower NK cell numbers than patients who reported a CES-D score of less than 16 (F1,21= 9.39, P = .003). A robust trend was found in which NK cell number was associated with survival. A mediational model linking depressive symptoms and survival, with NK cell number as a mediator, was preliminarily supported.

Conclusion

Secondary to the high prevalence of depressive symptoms and impact on survival, psychological and pharmacologic interventions should be designed and implemented in patients diagnosed with HBC.

The role of regulatory T cells in the control of natural killer cells: relevance during tumor progression

Tumor immunosurveillance relies on cognate immune effectors [lymphocytes and interferon-gamma (IFN-gamma)] and innate immunity [natural killer (NK) cells, natural killer group 2, member D (NKG2D) ligands, perforin/granzyme, and tumor necrosis factor-related apoptosis-inducing ligand]. In parallel, tumor cells promote the expansion of CD4(+)CD25(+) regulatory T cells (Tregs) that counteract T-cell-based anti-tumor immunity. Moreover, accumulating evidence points to a critical role for Tregs in dampening NK cell immune responses. This review summarizes the findings showing that Tregs suppress NK cell effector functions in vitro and in vivo, i.e. homeostatic proliferation, cytotoxicity, and interleukin-12-mediated IFN-gamma production. The molecular mechanism involve selective expression of membrane-bound transforming growth factor-beta on Tregs, which downregulate NKG2D expression on NK cells in vitro and in vivo. The regulatory events dictating NK cell suppression by Tregs have been studied and are discussed. The pathological relevance of the Treg-NK cell interaction has been brought up in tumor models and in patients with cancer. Consequently, inhibition of Tregs through pharmacological interventions should be considered during NK-cell-based immunotherapy of cancer.

Natural mechanisms protecting against cancer

Carcinogenesis is a multistage process. At each step of this process, there are natural mechanisms protecting against development of cancer. The majority of cancers in humans is induced by carcinogenic factors present in our environment including our food. However, some natural substances present in our diet or synthesized in our cells are able to block, trap or decompose reactive oxygen species (ROS) participating in carcinogenesis. Carcinogens can also be removed from our cells. If DNA damage occurs, it is repaired in most of the cases. Unrepaired DNA alterations can be fixed as mutations in proliferating cells only and mutations of very few strategic genes can induce tumor formation, the most relevant are those activating proto-oncogenes and inactivating tumor suppressor genes. A series of mutations and/or epigenetic changes is required to drive transformation of a normal cell into malignant tumor. The apparently unrestricted growth has to be accompanied by a mechanism preserving telomeres which otherwise shorten with succeeding cell divisions leading to growth arrest. Tumor can not develop beyond the size of 1-2mm in diameter without the induction of angiogenesis which is regulated by natural inhibitors. To invade the surrounding tissues epithelial tumor cells have to lose some adhesion molecules keeping them attached to each other and to produce enzymes able to dissolve the elements of the basement membrane. On the other hand, acquisition of other adhesion molecules enables interaction of circulating tumor cells with endothelial cells facilitating extravasation and metastasis. One of the last barriers protecting against cancer is the activity of the immune system. Both innate and adaptive immunity participates in anti-tumor effects including the activity of natural killer (NK) cells, natural killer T cells, macrophages, neutrophils and eosinophils, complement, various cytokines, specific antibodies, and specific T cytotoxic cells. Upon activation neutrophils and macrophages are able to kill tumor cells but they can also release ROS, angiogenic and immunosuppressive substances. Many cytokines belonging to different families display anti-tumor activity but their role in natural anti-tumor defense remains largely to be established.

CAM and NK Cells

It is believed that tumor development, outgrowth and metastasis are under the surveillance of the immune system. Although both innate and acquired immune systems play roles, innate immunity is the spearhead against tumors. Recent studies have revealed the critical role of natural killer (NK) cells in immune surveillance and that NK cell activity is considerably influenced by various agents, such as environmental factors, stress, foods and drugs. Some of these NK cell stimulants have been used in complementary and alternative medicine (CAM) since ancient times. Therefore, the value of CAM should be re-evaluated from this point of view. In this review, we overview the intimate correlation between NK cell functions and CAM agents, and discuss possible underlying mechanisms mediating this. In particular, neuro-immune crosstalk and receptors for CAM agents are the most important and interesting candidates for such mechanisms.

Prognostic significance of natural killer cell activity in patients with gastric carcinoma: a multivariate analysis

OBJECTIVE

Natural cytotoxicity, mediated by natural killer (NK) cells, has been believed to play an important role in inhibiting experimental tumor metastasis, and diminished NK cell activities leads to a high incidence of tumor occurrence. Despite convincing evidence from experimental studies, the role of NK cells in the immunological surveillance against cancer in human is poorly defined.

METHODS

The present study was based on a retrospective analysis of data on 156 patients with gastric cancer, who were surgically treated in the Department of Surgery II, Kyushu University Hospital from 1993 to 1996. All patients were examined for NK cell activity based on a peripheral blood sampling done preoperatively.

RESULTS

Significant association between NK cell activity and clinicopathological parameters including tumor size, lymphatic involvement, vascular involvement, and lymph node metastases was evident. When comparing the two groups according to NK cell activity, tumors with low NK cell activity tend to have lymphatic involvement. The 5-yr survival rates were 94.6% and 72.3% for those with NK cell activity > 25% lysis and < or = 25% lysis, respectively, the value being statistically significant (p < 0.05). The independent risk factors for prognosis examined by logistic regression analysis were lymphatic involvement. NK cell activity, depth of tumor invasion, and lymph node dissection.

CONCLUSIONS

These current data showed that NK cell activity may be related to tumor volume and dissemination. Measurement of preoperative NK cell activity may be pertinent for the prognosis of patients with gastric cancer and for follow-up clinical management.

Lymphocyte subsets as prognostic markers for cancer patients receiving immunomodulative therapy

Immunogenic features of some malignancies have aroused interest in immunotherapy of cancer. Immunotherapy seems most effective in patients with a small tumour burden, and the focus of immunotherapy trials has, thus, lately been on adjuvant treatment. To enable further development of immunotherapy we need to know more about the mechanisms involved in host defence, especially when the system is influenced by extrinsic factors, that is, immunomodulative agents. T lymphocytes play an important role in the host defence against tumour cells trying to escape from immune surveillance. The mechanisms that regulate the host defence systems are complex, and the influence of extrinsic factors such as immunotherapeutic agents is poorly understood. Most data on lymphocyte subsets in malignant disease originate from melanoma or renal cell carcinoma (RCC) studies, although there are scattered data on lymphocyte subsets also in other malignancies. There are several studies implying that the relative amount of CD4+, CD8+, and natural killer (NK) cells may be important and that, by reducing the tumour burden or by using different therapeutic agents, we can stimulate the host defence. However, only some of these studies imply that these changes can have an impact on clinical outcome and prognosis. The findings of the studies reviewed in this paper are mostly encouraging, but whether the lymphocyte subsets have any value as prognostic markers in patients with malignancies receiving immunotherapy is still unclear. Large randomized immunotherapy trials including an observation arm give an ideal opportunity to recognize those immunological changes that are due to therapy, related to the natural host defence, or whether they have any prognostic value.

Natural killer cell activity in patients with hepatocellular carcinoma: a new prognostic indicator after hepatectomy

BACKGROUND

Natural cytotoxicity mediated by natural killer (NK) cells is believed to play an important role in host anticancer defense mechanisms. The aim of this study was to examine the prognostic significance of NK cell activity after hepatectomy in patients with hepatocellular carcinoma.

METHODS

The NK cell activity in 210 patients with hepatocellular carcinoma was measured and evaluated in relation to clinicopathologic variables using univariate and multivariate analyses.

RESULTS

The NK cell activity was decreased significantly in hepatocellular carcinoma patients compared with the control groups (P < 0.001). No correlation was observed between NK cell activity and the clinicopathologic variables. Multivariate analyses indicated that NK cell activity as well as intrahepatic metastases, platelet count, and serum albumin level were independent prognostic factors.

CONCLUSIONS

This study suggests that the preoperative NK cell activity will help predict recurrence and prognosis after hepatectomy in patients with hepatocellular carcinoma.

[Immunocytochemical venous blood studies in patients with manifest oral cavity carcinomas, oral precancerous conditions, benign tumors and in chronic alcoholic patients]

In a prospective pilot study we investigated the percentage of immunocompetent cells in the peripheral blood in 146 patients (lymphocytes, leucocytes, monocytes, T cells, B cells, NK cells, T-helper cells, T-suppressor cells, ratio T-helper/T-suppressor cells, activated T cells HLA-DR) by flow cytometry. The immunologic parameters were derived from patients with oral and oropharyngeal squamous cell carcinomas, precancerous lesions and benign tumours and from a group of heavy smokers and alcoholics. Carcinoma patients (n = 46) were compared with risk groups and a reference group consisting of patients with inflammatory disease. Within the collective of carcinoma patients we measured the immune status before and after chemo-, radio- and operative therapy. We also analysed the immune parameters in relation to clinical and histomorphological parameters (TNM status, grading). The univariate analysis of monocytes showed significant relationships between on the one hand carcinoma patients and on the other alcoholics and those with benign tumours and precancerous lesions. In precancerous lesions NK cells were significantly increased compared with alcoholics and the reference group. A significant decrease in B cells in carcinoma patients may show incipient insufficiency of the humoral immunity. The immune parameters showed a different reaction depending on therapy. After irradiation we found a significant increase of T-suppressor cytotoxic cells and decreases in B and T-helper cells. Chemotherapy showed an increase in T and T-helper cells and a decrease in B cells. Surgical therapy alone yielded an increase in B cells. The comparison of all pre- and posttherapeutic parameters showed significant changes only in activated T cells HLA-DR. We found no correlation between prognostic clinico-pathological factors and immune parameters. No changes were found in a multivariate analysis.

Natural killer cells and cancer

BACKGROUND

Natural cytotoxicity, mediated by natural killer (NK) cells and cell with lymphokine-activated killer (LAK) activity, is believed to play an important role in host anti-cancer mechanisms.

METHODS

The authors critically review recent publications on the role of natural cytotoxicity in patients with cancer.

RESULTS

In patients with cancer, several studies have noted variations in the numbers and activity of NK and cells with LAK activity in different body compartments. NK cell activity in the peripheral blood lymphocytes (PBLs) is higher than that found in lymph nodes and within tumors, and this appears to be due to the presence of suppressor factors. The natural cytotoxicity of PBLs in patients with different types of cancers varies. However, there appears to be a trend for natural cytotoxicity to be reduced in certain cancer patients, possibly related to tumor volume or dissemination. Anti-cancer treatments (e.g., surgery, hormonal modulation, radiotherapy and chemotherapy) can also result in suppression of natural cytotoxicity, although the long-term effect on response to treatment and development of metastases is at present unknown.

CONCLUSIONS

NK and LAK cells, through the use of immune biologic modifiers, have been demonstrated to have a therapeutic role in the treatment of human cancers. Further studies are required to determine the optimal dosages and combinations of chemotherapeutic agents, the timing of surgery, and the adjuvant use of immune biologic response modifiers. An increasing awareness and understanding of this field, may allow for the future development of anti-cancer therapies.

Effects of anesthesia based on large versus small doses of fentanyl on natural killer cell cytotoxicity in the perioperative period

Surgical stress and general anesthesia suppress immune functions, including natural killer cell cytotoxicity (NKCC). This suppression could be attributable, at least in part, to opiates. We have previously shown that large-dose fentanyl administration suppressed NKCC in rats. The present study sought to compare the effects of two anesthetic protocols, based on large- (LDFA) versus small (SDFA)-dose fentanyl anesthesia on NKCC in the perioperative period. Forty patients were included in this study; half were assigned to each protocol of anesthesia. In each anesthetic group, half the patients were undergoing surgery for malignant diseases, and half for benign conditions. Blood samples were collected during the perioperative period. NKCC was assessed using the chromium release assay. Initially, both types of anesthesia similarly suppressed NKCC, with a peak effect 24 h after surgery. The two types of anesthesia, however, differed in the rate of recovery of NKCC suppression. By the second postoperative day, NKCC returned to control values in the SDFA patients, whereas NKCC was still significantly suppressed after LDFA. These results indicate that LDFA causes prolonged suppression of NK cell function. Whether this suppression might have a long-term impact on the overall outcome, especially in cancer patients, remains to be determined.

Sera from patients with colon, breast and lung cancer induce resistance to lysis mediated by NK cytotoxic factors (NKCF)

Natural killer (NK) cells are involved in the antitumoral immunologic mechanism. These cells act through the release of cytotoxic molecules defined as NK cytotoxic factors (NKCF). Inhibitory factors of NK and NKCF mediated lysis have been described in in vitro assays. This study evaluates the induction of resistance to NKCF cytotoxicity by sera from 27 patients with colon, breast and lung cancer. Addition of these sera to the cytolytic assay where K562 cells and concentrated NKCF were used, induced resistance to NKCF mediated cytotoxicity in 21 cases (77%). The sera from the group with metastasis blocked NKCF lysis more markedly than the group with local tumours. However, no differences were observed when the groups with colon, breast and lung cancers were compared. This blocking effect was not found to be related to gamma interferon (IFN) levels. In a previous study, we described a tumour factor (NK-RIF) produced by human cell lines derived from metastatic adenocarcinomas. This factor blocked lysis of tumour target cells by NK cells. Consequently, it is proposed that the release of similar tumour factors with a capacity to induce resistance to NKCF may be involved in tumour growth and metastatic spreading in in vivo.

Preoperative cell-mediated immune function and the prognosis of patients with gastric carcinoma

The cell-mediated immune function of 83 patients with gastric carcinoma was assessed preoperatively and the results were compared to that of 52 patients with benign lesions. The data were subjected to an analysis in order to evaluate their prognostic significance. The abilities to induce allogeneic cytotoxicity and to produce interleukin 2 (IL2) in patients with stage IV carcinoma were significantly depressed, as compared to those in patients with benign lesions, whereas natural killer (NK) cell activity was not significantly impaired. There was no significant correlation among these immune functions. When the patients were stratified into two groups, those who had high (greater than the mean value in patients with benign lesions) and low (less than the same value) values of these immune reactivities, the survival of patients with high NK activity (greater than or equal to 43%) was significantly better, as compared to that of patients with low cytotoxicity (less than 43%). However, there was no correlation between the survival and allogeneic cytotoxicity in these patients. The high ability to produce IL2 (greater than or equal to 1.3 U/ml) correlated with the better survival in the patients, but not in the group of patients who underwent curative resection.

Natural killer cells and metastases from pharyngeal carcinoma

Natural killer cell activity was assessed in 100 previously untreated pharyngeal carcinoma patients. Diminished natural killer cell function in these patients was associated with an increased risk of death from uncontrolled regional and distant metastases. During the assessment, the cell line MDA686-Ln was established from a metastatic pharyngeal carcinoma of a patient with low natural killer cell cytotoxicity. The initially cytotoxicity-resistant cell line could be lysed when natural killer cell cytotoxicity was enhanced in vitro either through enrichment of a Leu 19+ natural killer cell population by fluorescent-activated cell sorting or by interleukin-2 activation. Additionally, increased circulating immune complexes were identified in these patients, subsequently isolated, and found to block natural killer cell reactivity against MDA686-Ln. In light of this negative interaction, 38 patients were randomly evaluated for both circulating immune complex levels and natural killer cell function. Both parameters examined together were complementary in defining the risk of death with disease; four of five deaths occurred in patients with both high circulating immune complex levels and low natural killer cell function. Results support the biologic modification of natural killer cell activity for controlling metastatic pharyngeal carcinoma and point to the potential confounding influence of circulating immune complex.

Transfusion history, T cell subsets and natural killer cytotoxicity in patients with colorectal cancer

Blood transfusions are associated with clinical phenomena which are attributable to immune suppression. Since suppression of immune function is associated with a high risk of spontaneous malignancies, we studied T cell subsets and natural killer (NK) cytotoxicity in colorectal cancer patients and correlated the results with patients' transfusion histories. Twelve percent (14) of the 115 patients had been transfused an average of 19 years previously. Recipients of blood transfusions had low levels of peripheral lymphocytes (p = 0.191), T cells (p = 0.015), helper cells (p = 0.016) and suppressor cells (p = 0.2651) compared to previously untransfused patients. NK cytotoxicity was also significantly reduced in transfusion recipients although NK cell numbers were comparable in both groups. These results support previous studies indicating that blood transfusions cause lifelong immune modulation in the recipient. Since blood transfusions have numerous beneficial effects and immune modulation is often beneficial, longitudinal studies are necessary to define the lifetime risks and benefits.