Natural killer cells enhance the immune surveillance of cancer

A systematic evidence map of chronic inflammation and immunosuppression related to per- and polyfluoroalkyl substance (PFAS) exposure

BACKGROUND

The ability to induce chronic inflammation and immunosuppression are two key characteristics of carcinogens and important forms of immunotoxicity. The National Toxicology Program (NTP) evaluated the immunotoxicity of two per- and polyfluoroalkyl substances (PFASs), PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonate), in 2016. However, the potential pro-inflammatory and immunosuppressive effects of other PFASs remain largely uncharacterized.

METHODS

We developed an expanded set of search terms pertaining to the chronic inflammatory and immunosuppressive effects of PFASs based on those of the International Agency for Research on Cancer (IARC) and NTP. To confirm searching effectiveness and scope, we compared our search term results with those of IARC and NTP for both PFASs and two other known carcinogens, chromium (VI) and benzene. Systematic evidence maps (SEMs) were also produced using Tableau to visualize the distribution of study numbers and types reporting immunotoxic effects and specific biomarkers elicited by PFAS exposures.

RESULTS

In total, 1155 PFAS studies were retrieved, of which 321 qualified for inclusion in our dataset. Using our search terms, we identified a greater number of relevant studies than those obtained using IARC and NTP's search terms. From the SEM findings, increased cytokine production strengthened an association between PFAS exposure and chronic inflammation, and decreased B-cell activation and altered levels of T-cell subtypes and immunoglobulins confirmed PFAS-induced immunosuppression.

CONCLUSION

Our SEM findings confirm that several PFASs commonly found in both in the environment, including those that are lesser-known, may induce immunosuppression and chronic inflammation, two key characteristics of carcinogens. This approach, including development of search terms, study screening process, data coding, and evidence mapping visualizations, can be applied to other key characteristics of chemical carcinogens.

Immunomodulating Therapy by Picibanil-based Imiquimod and Virotherapy for Advanced Uterine Cancer after Laparoscopic Surgery

This is a case report of a uterine cancer with the International Federation of Gynecology and Obstetrics staging 3c2 with the initial clinical presentation of postmenopausal vaginal bleeding in August 2015. Endometrium biopsy showed invasive nests of poorly differentiated grade 3 endometrioid adenocarcinoma. The patient received robotic surgery including total hysterectomy, bilateral salpingo-oophorectomy, bilateral pelvic lymph node dissection, para-aortic lymph node dissection, and washing cytology. The final pathology showed an endometrioid carcinoma with myometrium invasion up to 85% and para-aortic and pelvic lymph nodes invasion. The patient received six courses of adjuvant chemotherapy (paclitaxel and carboplatin) with concurrent chemoradiotherapy after the surgery. Later, immunotherapy with Picibanil (OK-432) and interleukin-2 (IL-2) was given, and cancer did not recur for 34 months until tumor recurrence at the liver dome and bilateral lung was noted by positron-emission tomography scan in July 2018. The patient received laparoscopic surgery for intra-abdominal tumor excision in December 2018, and the tumor found extended to the right diaphragm, liver surface, omentum, bilateral flank to pelvic peritoneum, Douglas pouch, and upper rectum. We continued the immunotherapy with OK-432, IL-2, Aldara cream (imiquimod), and later on, virotherapy (human papillomavirus vaccine). The immune risk profiles showed T–cells' proliferation and alteration of the Th1/Th2 activation after immunotherapy and virotherapy. Proctectomy with colon-anal anastomosis and cytoreduction surgery with hyperthermic intraperitoneal chemotherapy (HIPEC) (doxorubicin and paclitaxel) was performed in January 2019. After the surgery, the patient received chemotherapy (topotecan, paclitaxel, lipodox, and carboplatin) and continued the immunotherapy. The immune risk profiles showed CD4, CD4/CD8 increase after HIPEC and immunotherapy. The patient continued the therapy until May 2020.

Iron deficiency, immunology, and colorectal cancer

Excessive gut luminal iron contributes to the initiation and progression of colorectal cancer. However, emerging evidence suggests that reduced iron intake and low systemic iron levels are also associated with the pathogenesis of colorectal cancer. This is important because patients with colorectal cancer often present with iron deficiency. Iron is necessary for appropriate immunological functions; hence, iron deficiency may hinder cancer immunosurveillance and potentially modify the tumor immune microenvironment, both of which may assist cancer development. This is supported by studies showing that patients with colorectal cancer with iron deficiency have inferior outcomes and reduced response to therapy. Here, we provide an overview of the immunological consequences of iron deficiency and suggest ensuring adequate iron therapy to limit these outcomes.

Traditional uses, chemical components and pharmacological activities of the genus Ganoderma P. Karst.: a review

In recent years, some natural products isolated from the fungi of the genus Ganoderma have been found to have anti-tumor, liver protection, anti-inflammatory, immune regulation, anti-oxidation, anti-viral, anti-hyperglycemic and anti-hyperlipidemic effects. This review summarizes the research progress of some promising natural products and their pharmacological activities. The triterpenoids, meroterpenoids, sesquiterpenoids, steroids, alkaloids and polysaccharides isolated from Ganoderma lucidum and other species of Ganoderma were reviewed, including their corresponding chemical structures and biological activities. In particular, the triterpenes, polysaccharides and meroterpenoids of Ganoderma show a wide range of biological activities. Among them, the hydroxyl groups on the C-3, C-24 and C-25 positions of the lanostane triterpenes compound were the necessary active groups for the anti-HIV-1 virus. Previous study showed that lanostane triterpenes can inhibit human immunodeficiency virus-1 protease with an IC₅₀ value of 20–40 μM, which has potential anti-HIV-1 activity. Polysaccharides can promote the production of TNF α and IFN-γ by macrophages and spleen cells in mice, and further inhibit or kill tumor cells. Some meroterpenoids contain oxygen-containing heterocycles, and they have significant antioxidant activity. In addition, Ganoderma has been used as a medicine to treat diseases for more than 2000 years, and we also reviewed its traditional uses.

In recent years, some natural products isolated from the fungus of the genus Ganoderma have been found to have anti-tumor, liver protection, anti-inflammatory, immune regulation, anti-oxidation, anti-viral, anti-hyperglycemic and anti-hyperlipidemic effects.

Modulation of NKG2D, KIR2DL and Cytokine Production by Pleurotus ostreatus Glucan Enhances Natural Killer Cell Cytotoxicity Toward Cancer Cells

Medicinal mushrooms have been used for centuries against cancer and infectious diseases. These positive biological effects of mushrooms are due in part to the indirect action of stimulating immune cells. The objective of the current study is to investigate the possible immunomodulatory effects of mushroom polysaccharides on NK cells against different cancer cells. In this current study, fruiting bodies isolated from cultured Pleurotus ostreatus were extracted and partially purified using DEAE ion-exchange chromatography. The activation action of the collected fractions on Natural Killer cells was quantified against three different cancer cell lines in the presence or absence of human recombinant IL2 using three different activation and co-culture conditions. The possible modes of action of mushroom polysaccharides against cancer cells were evaluated at the cellular and molecular levels. Our results indicate that P. ostreatus polysaccharides induced NK-cells cytotoxic effects against lung and breast cancer cells with the largest effect being against breast cancer cells (81.2%). NK cells activation for cytokine secretion was associated with upregulation of KIR2DL genes while the cytotoxic activation effect of NK cells against cancer cells correlated with NKG2D upregulation and induction of IFNγ and NO production. These cytotoxic effects were enhanced in the presence of IL2. Analysis of the most active partially purified fraction indicates that it is predominantly composed of glucans. These results indicate bioactive 6-linked glucans present in P. ostreatus extracts activate NK-cell cytotoxicity via regulation of activation and induction of IFNγ and NO. These studies establish a positive role for bioactive P. ostreatus polysaccharides in NK-cells activation and induction of an innate immune response against breast and lung cancer cells.

Deficiencies in Natural Killer Cell Numbers, Expansion, and Function at the Pre-Neoplastic Stage of Pancreatic Cancer by KRAS Mutation in the Pancreas of Obese Mice

The combined/synergistic effect of genetic mutation of KRAS in the pancreas and obesity, a life-style factor on suppression of natural killer (NK) cells at the pre-neoplastic stage of pancreatic cancer has not been investigated and is the subject of this report. Obese mice with KRAS (KC) mutation in the pancreas fed with high-fat calorie diet (HFCD) exhibit severe deficiencies in the NK cell expansion and function at the pre-neoplastic stage of pancreatic cancer. Decreased NK cell-mediated cytotoxicity is observed in the peripheral blood, spleen, pancreas, and peri-pancreatic adipose tissue in obese KC mice, whereas in bone marrow an increased NK cell-mediated cytotoxicity is observed when compared to lean WT mice fed with control diet (CD). Obese KC mice on HFCD demonstrated the least ability to expand NK cells or induce NK cell-mediated cytotoxicity when compared to the other groups of mice. Indeed, the following profile WT/CD > WT/HFCD > KC/CD > KC/HFCD was seen for the ability to expand NK cells or mediate cytotoxicity among four groups of mice in spleen, peripheral blood, pancreas, and peri-pancreatic adipose tissue. Sorted NK cells from the splenocytes of four groups of mice also exhibited the same profiles for the cytotoxicity as the unsorted splenocytes, and a decreased IFN-γ secretion could be seen in cultures of NK cells from KC mice fed with either CD or HFCD. Cultures of NK cells with autologous monocytes from obese KC mice fed with HFCD exhibited decreased cytotoxicity and IFN-γ secretion, whereas cultures of allogeneic NK cells from WT mice fed with CD with osteoclasts of obese mice fed with HFCD demonstrated decreased cytotoxicity but augmented IFN-γ secretion. Increased IL-6 along with decreased IFN-γ and cell-mediated cytotoxicity by the NK cells, within NK-adipose tissue of KC/HFCD mice, may provide safe microenvironment for the expansion of pancreatic tumors.

Modeling Macrophage Polarization and Its Effect on Cancer Treatment Success

Positive feedback loops drive immune cell polarization toward a pro-tumor phenotype that accentuates immunosuppression and tumor angiogenesis. This phenotypic switch leads to the escape of cancer cells from immune destruction. These positive feedback loops are generated by cytokines such as TGF-β, Interleukin-10 and Interleukin-4, which are responsible for the polarization of monocytes and M1 macrophages into pro-tumor M2 macrophages, and the polarization of naive helper T cells intopro-tumor Th2 cells. In this article, we present a deterministic ordinary differential equation (ODE) model that includes key cellular interactions and cytokine signaling pathways that lead to immune cell polarization in the tumor microenvironment. The model was used to simulate various cancer treatments in silico. We identified combination therapies that consist of M1 macrophages or Th1 helper cells, coupled with an anti-angiogenic treatment, that are robust with respect to immune response strength, initial tumor size and treatment resistance. We also identified IL-4 and IL-10 as the targets that should be neutralized in order to make these combination treatments robust with respect to immune cell polarization. The model simulations confirmed a hypothesis based on published experimental evidence that a polarization into the M1 and Th1 phenotypes to increase the M1-to-M2 and Th1-to-Th2 ratios plays a significant role in treatment success. Our results highlight the importance of immune cell reprogramming as a viable strategy to eradicate a highly vascularized tumor when the strength of the immune response is characteristically weak and cell polarization to the pro-tumor phenotype has occurred.