IL-6 mediates platinum-induced enrichment of ovarian cancer stem cells

In high-grade serous ovarian cancer (OC), chemotherapy eliminates the majority of tumor cells, leaving behind residual tumors enriched in OC stem cells (OCSC). OCSC, defined as aldehyde dehydrogenase–positive (ALDH+), persist and contribute to tumor relapse. Inflammatory cytokine IL-6 is elevated in residual tumors after platinum treatment, and we hypothesized that IL-6 plays a critical role in platinum-induced OCSC enrichment. We demonstrate that IL-6 regulates stemness features of OCSC driven by ALDH1A1 expression and activity. We show that platinum induces IL-6 secretion by cancer-associated fibroblasts in the tumor microenvironment, promoting OCSC enrichment in residual tumors after chemotherapy. By activating STAT3 and upregulating ALDH1A1 expression, IL-6 treatment converted non-OCSC to OCSC. Having previously shown altered DNA methylation in OCSC, we show here that IL-6 induces DNA methyltransferase 1 (DNMT1) expression and the hypomethylating agent (HMA) guadecitabine induced differentiation of OCSC and reduced — but did not completely eradicate — OCSC. IL-6 neutralizing antibody (IL-6-Nab) combined with HMA fully eradicated OCSC, and the combination blocked IL-6/IL6-R/pSTAT3–mediated ALDH1A1 expression and eliminated OCSC in residual tumors that persisted in vivo after chemotherapy. We conclude that IL-6 signaling blockade combined with an HMA can eliminate OCSC after platinum treatment, supporting this strategy to prevent tumor recurrence after standard chemotherapy

Combination of vasculature targeting, hypofractionated radiotherapy, and immune checkpoint inhibitor elicits potent antitumor immune response and blocks tumor progression

Background: Tumor endothelial marker 1 (TEM1) is a protein expressed in the tumor-associated endothelium and/or stroma of various types of cancer. We previously demonstrated that immunization with a plasmid-DNA vaccine targeting TEM1 reduced tumor progression in three murine cancer models. Radiation therapy (RT) is an established cancer modality used in more than 50% of patients with solid tumors. RT can induce tumor-associated vasculature injury, triggering immunogenic cell death and inhibition of the irradiated tumor and distant non-irradiated tumor growth (abscopal effect). Combination treatment of RT with TEM1 immunotherapy may complement and augment established immune checkpoint blockade. Methods: Mice bearing bilateral subcutaneous CT26 colorectal or TC1 lung tumors were treated with a novel heterologous TEM1-based vaccine, in combination with RT, and anti-programmed death-ligand 1 (PD-L1) antibody or combinations of these therapies, tumor growth of irradiated and abscopal tumors was subsequently assessed. Analysis of tumor blood perfusion was evaluated by CD31 staining and Doppler ultrasound imaging. Immunophenotyping of peripheral and tumor-infiltrating immune cells as well as functional analysis was analyzed by flow cytometry, ELISpot assay and adoptive cell transfer (ACT) experiments. Results: We demonstrate that addition of RT to heterologous TEM1 vaccination reduces progression of CT26 and TC1 irradiated and abscopal distant tumors as compared with either single treatment. Mechanistically, RT increased major histocompatibility complex class I molecule (MHCI) expression on endothelial cells and improved immune recognition of the endothelium by anti-TEM1 T cells with subsequent severe vascular damage as measured by reduced microvascular density and tumor blood perfusion. Heterologous TEM1 vaccine and RT combination therapy boosted tumor-associated antigen (TAA) cross-priming (ie, anti-gp70) and augmented programmed cell death protein 1 (PD-1)/PD-L1 signaling within CT26 tumor. Blocking the PD-1/PD-L1 axis in combination with dual therapy further increased the antitumor effect and gp70-specific immune responses. ACT experiments show that anti-gp70 T cells are required for the antitumor effects of the combination therapy. Conclusion: Our findings describe novel cooperative mechanisms between heterologous TEM1 vaccination and RT, highlighting the pivotal role that TAA cross-priming plays for an effective antitumor strategy. Furthermore, we provide rationale for using heterologous TEM1 vaccination and RT as an add-on to immune checkpoint blockade as triple combination therapy into early-phase clinical trials

Involvement of tumor endothelial marker 8 (TEM8) in proangiogenic and cell-migratory programs

The mammalian immune system is composed of many cell types and mediators that interact with non-immune cells and each other in complex and dynamic networks to ensure protection against foreign pathogens, while simultaneously maintaining tolerance towards self-antigens.\ud Based on antigen specificity and timing of activation, the immune system is composed of two distinct compartments — adaptive and innate.\ud Innate immune cells including dendritic cells (DCs), macrophages, neutrophils, basophils, eosinophils, natural killer (NK) and mast cells are the first line of defence against foreign pathogens.\ud The unique characteristic of innate immune cells — their inherent ability to rapidly respond when tissue injury occurs, without memory of previous assaults or antigen specificity — is a defining feature that sets them apart from adaptive immune cells.\ud Adaptive immune cells, B and T lymphocytes, produced by stem cells in the bone marrow, mature in the thymus and/or lymph nodes and ensure that most mammals that survive an initial infection by a pathogen are generally immune to further illness caused by that same pathogen

ENHANCING RADIATION SENSITIVITY IN NON-SMALL CELL LUNG CANCER

Lung cancer is the leading cause of cancer-related death. While radiation therapy is one of the standard treatments for lung cancer, the disease outcome after radiotherapy is still far from satisfactory despite ongoing advances in radiation techniques. Enhancing the radiosensitivity of lung cancer has the potential to improve the disease outcome of radiation treatments. Using a novel high throughput radiation sensitizing screen, previous work in the lab has identified several potent radiation sensitizers. The focus of my dissertation is on two of the identified pathways, HSP90 and MEK, using the potent and clinically relevant inhibitors ganetespib and trametinib. Using both in vitro experiments in multiple non-small cell lung cancer (NSCLC) cell lines and in vivo experiments in animal models, I tested the ability of these inhibitors to radiosensitize lung tumors in the clinically relevant context of chemoradiation. I have found that ganetespib sensitized lung cancer cells to radiation through attenuating DNA damage repair through attenuating DNA damage repair and accentuating G2-M cell cycle arrest. However, when combined with chemoradiation in vivo, ganetespib has variable effects on different cells. For radiation sensitization through MEK inhibition, I found that trametinib selectively sensitized KRAS-LKB1 co-mutant NSCLC, but not KRAS-TP53 mutant cells, through radiation-induced senescence. In the LKB1 wild type background, trametinib and radiation activated AMPK-autophagy pathway to rescue cells from senescence, therefore conferring resistance to the radiosensitization. In summary, my studies which focused on how these two specific targeted pathways caused radiation sensitization emphasized the need to better understand the molecular and signaling complexities in determining radiation sensitization effects especially when multiple modalities are combined. Preclinical studies in the context of clinically relevant treatment settings are warranted for optimal clinical translation and personalized cancer therapy

Ketogenic Therapy as an Adjuvant for Malignant Glioma: Impacts on Anti-Tumor Immunity

abstract: Malignant brain tumors are devastating despite aggressive treatments such as surgical resection, chemotherapy and radiation therapy. The average life expectancy of patients with newly diagnosed glioblastoma is approximately 15 months. One novel therapeutic strategy involves using a ketogenic diet (KD) which increases circulating ketones and reduces circulating glucose. While the preclinical work has shown that the KD increases survival, enhances radiation and alters several pathways in malignant gliomas, its impact on the anti-tumor immune response has yet to be examined. This dissertation demonstrates that mice fed the KD had increased tumor-reactive innate and adaptive immune responses, including increased cytokine production and cytolysis via tumor-reactive CD8+ T cells. Additionally, we saw that mice maintained on the KD had increased CD4 infiltration, while T regulatory cell numbers stayed consistent. Lastly, mice fed the KD had a significant reduction in immune inhibitory receptor expression as well as decreased inhibitory ligand expression on glioma cells, namely programmed death receptor -1 (PD-1) and its ligand programmed death receptor ligand -1 (PD-L1). Further, it is demonstrated that the ketone body beta-hydroxybutyrate (BHB) reduces expression of PD-L1 on glioma cells in vitro suggesting it may be responsible in part for immune-related changes elicited by the KD. Finally this dissertation also shows that the KD increases the expression of microRNAs predicted to target PD-L1 suggesting a potential mechanism to explain the ability of the KD to modulate immune inhibitory checkpoint pathways. Taken together these studies shed important light on the mechanisms underlying the KD and provide additional support for its use an adjuvant therapy for malignant glioma.Dissertation/ThesisDoctoral Dissertation Biology 201

The role of the immune system in brain metastasis

Metastatic brain tumors are the most common brain tumors in adults. With numerous successful advancements in systemic treatment of most common cancer types, brain metastasis is becoming increasingly important in the overall prognosis of cancer patients. Brain metastasis of peripheral tumor is the result of complex interplay of primary tumor, immune system and central nervous system microenvironment. Once formed, brain metastases hide behind the blood brain barrier and become inaccessible to chemotherapies that are otherwise successful in targeting systemic cancer. The approval of immune checkpoint inhibitors for several common cancers such as advanced melanoma and lung cancers brings with it the opportunity and obligation to further understand the mechanisms of immunosuppression by tumors that spread to the brain as well as the interaction between the brain environment and tumor microenvironment. In this review paper we define the central role of the immune system in the development of brain metastases. We performed a comprehensive review of the literature to outline the molecular mechanisms of immunosuppression used by tumors and how the immune system interacts with the central nervous system to facilitate brain metastasis. In particular we discuss the tumor-type-specific mechanisms of metastasis of cancers that preferentially metastasize to the brain as well as the therapies that effectively modulate the immune response, such as immune checkpoint inhibitors and vaccines

Metallic Nanoparticles for the Modulation of Tumor Microenvironment; A New Horizon

Cancer is one of the most critical human challenges which endangers many people’s lives every year with enormous direct and indirect costs worldwide. Unfortunately, despite many advanced treatments used in cancer clinics today, the treatments are deficiently encumbered with many side effects often encountered by clinicians while deploying general methods such as chemotherapy, radiotherapy, surgery, or a combination thereof. Due to their low clinical efficacy, numerous side effects, higher economic costs, and relatively poor acceptance by patients, researchers are striving to find better alternatives for treating this life-threatening complication. As a result, Metal nanoparticles (Metal NPs) have been developed for nearly 2 decades due to their important therapeutic properties. Nanoparticles are quite close in size to biological molecules and can easily penetrate into the cell, so one of the goals of nanotechnology is to mount molecules and drugs on nanoparticles and transfer them to the cell. These NPs are effective as multifunctional nanoplatforms for cancer treatment. They have an advantage over routine drugs in delivering anticancer drugs to a specific location. However, targeting cancer sites while performing anti-cancer treatment can be effective in improving the disease and reducing its complications. Among these, the usage of these nanoparticles (NPs) in photodynamic therapy and sonodynamic therapy are notable. Herein, this review is aimed at investigating the effect and appliances of Metal NPs in the modulation tumor microenvironment which bodes well for the utilization of vast and emerging nanomaterial resources

Current approaches of tumor immunotherapy

Our immune system, fine-tuned by a long evolution, has a near-infinite capacity to recognize potential pathogens and mutant self proteins. It has also got a varied arsenal of killing mechanisms to battle intruders and mutant cells. Since malignant transformation involves 1) mutations of proteins of various classes and 2) over-expression of non-altered genes, either related or unrelated to the oncogenic process, the adaptive immune system has the potential to recognize and clear malignantly transformed cells. Immunotherapeutic interventions might 1) trigger an immune response to otherwise tolerated tumor antigens, 2) enhance the existing, but insufficient anti-tumor immune response, add new receptors, recombinant antibodies or T cell receptors, to the system, or 4) rely on the transfer of ex vivo expanded immune effector cells. Although tumor immunotherapy is decades-old, immune checkpoint inhibitor therapy, probably the most significant breakthrough, is a development of the last few years. Reaching its maturity, tumor immunotherapy is just now becoming an integral part of tumor therapy

Combinatory effects of the bioflavonoid apigenin with chemotherapeutic drugs on prostate, colon, and lung cancer cell lines

Lung, prostate, and colon cancer are among the most commonly diagnosed cancers in Americans. Current chemotherapeutic regimens generally have toxic side effects leading to the death of normal cells. Polyphenols are naturally occurring compounds that can be found in fruits, vegetables and herbs. Apigenin is a polyphenolic compound that has been shown to have antioxidant and anti-inflammatory effects. In this study, apigenin was shown to inhibit the proliferation of several cancer cell lines. The combination of 15 uM apigenin and the chemotherapeutic drugs including doxorubicin, etoposide, mitomycin C, and 5-fluorouracil significantly decreased (P\u3c0.05) the IC50 to inhibit the proliferation of prostate cancer cell lines PC-3 and DU-145 more than the chemotherapeutic drugs alone. Similarly, the addition of apigenin greatly enhanced the sensitivity of colon cancer cell lines HCT-116 and colo-205 and lung cancer lines A549 and H460 to doxorubicin, mitomycin C, 5-fluorouracil, and cisplatin. We analyzed sensitivity via cell death and cell proliferation assays

Current challenges and future perspectives

: The research group was funded by IPOLFG EPE and by iNOVA4Health (UID/Multi/04462/2019) a program financially supported by Fundação para a Ciência e Tecnologia (FCT)/Ministério da Educação e Ciência, through national funds. We also acknowledge funding from FCT-MCTES through Filipa Lopes-Coelho PhD (PD/BD/128337/2017).Anti-angiogenic therapy is an old method to fight cancer that aims to abolish the nutrient and oxygen supply to the tumor cells through the decrease of the vascular network and the avoidance of new blood vessels formation. Most of the anti-angiogenic agents approved for cancer treatment rely on targeting vascular endothelial growth factor (VEGF) actions, as VEGF signaling is considered the main angiogenesis promotor. In addition to the control of angiogenesis, these drugs can potentiate immune therapy as VEGF also exhibits immunosuppressive functions. Despite the mechanistic rational that strongly supports the benefit of drugs to stop cancer progression, they revealed to be insufficient in most cases. We hypothesize that the rehabilitation of old drugs that interfere with mechanisms of angiogenesis related to tumor microenvironment might represent a promising strategy. In this review, we deepened research on the molecular mechanisms underlying anti-angiogenic strategies and their failure and went further into the alternative mechanisms that impact angiogenesis. We concluded that the combinatory targeting of alternative effectors of angiogenic pathways might be a putative solution for anti-angiogenic therapies.publishersversionpublishe