A Progenitor Cell Expressing Transcription Factor RORγt Generates All Human Innate Lymphoid Cell Subsets.

The current model of murine innate lymphoid cell (ILC) development holds that mouse ILCs are derived downstream of the common lymphoid progenitor through lineage-restricted progenitors. However, corresponding lineage-restricted progenitors in humans have yet to be discovered. Here we identified a progenitor population in human secondary lymphoid tissues (SLTs) that expressed the transcription factor RORγt and was unique in its ability to generate all known ILC subsets, including natural killer (NK) cells, but not other leukocyte populations. In contrast to murine fate-mapping data, which indicate that only ILC3s express Rorγt, these human progenitor cells as well as human peripheral blood NK cells and all mature ILC populations expressed RORγt. Thus, all human ILCs can be generated through an RORγt(+) developmental pathway from a common progenitor in SLTs. These findings help establish the developmental signals and pathways involved in human ILC development.

IL-27 Gene Therapy Induces Stat3-Mediated Expansion of CD11b+Gr1+ Myeloid Cells and Promotes Accumulation of M1 Macrophages in the Tumor Microenvironment.

IL-27 is a pleiotropic cytokine that exhibits stimulatory/regulatory functions on multiple lineages of immune cells and has a potential to be used as a therapeutic for cancer. We have recently demonstrated that administration of IL-27 producing adeno-associated virus (AAV-IL-27) exhibits potent inhibition of tumor growth in mouse models. In this study, we demonstrate that AAV-IL-27 treatment leads to significant expansion of CD11b+Gr1+ myeloid cells. AAV-IL-27-induced expansion of CD11b+Gr1+ cells is IL-27R-dependent and requires Stat3 signaling, but it is inhibited by Stat1 signaling. AAV-IL-27 treatment does not increase the self-renewal capacity of CD11b+Gr1+ cells but induces significant expansion of Lin-Sca1+c-Kit+ (LSK) and granulocyte-monocyte progenitor cells. Despite exhibiting significant suppression of T cells in vitro, IL-27-induced CD11b+Gr1+ cells lost the tumor-promoting activity in vivo and overall play an antitumor role. In tumors from AAV-IL-27-treated mice, CD11b+Gr1+ cells are largely F4/80+ and express high levels of MHC class I/II and M1 macrophage markers. Thus, IL-27 gene therapy induces Stat3-mediated expansion of CD11b+Gr1+ myeloid cells and promotes accumulation of M1 macrophages in the tumor microenvironment.

Targeting metabolic sensing switch GPR84 on macrophages for cancer immunotherapy.

INTRODUCTION: As one of the major components of the tumor microenvironment, tumor-associated macrophages (TAMs) possess profound inhibitory activity against T cells and facilitate tumor escape from immune checkpoint blockade therapy. Converting this pro-tumorigenic toward the anti-tumorigenic phenotype thus is an important strategy for enhancing adaptive immunity against cancer. However, a plethora of mechanisms have been described for pro-tumorigenic differentiation in cancer, metabolic switches to program the anti-tumorigenic property of TAMs are elusive. MATERIALS AND METHODS: From an unbiased analysis of single-cell transcriptome data from multiple tumor models, we discovered that anti-tumorigenic TAMs uniquely express elevated levels of a specific fatty acid receptor, G-protein-coupled receptor 84 (GPR84). Genetic ablation of GPR84 in mice leads to impaired pro-inflammatory polarization of macrophages, while enhancing their anti-inflammatory phenotype. By contrast, GPR84 activation by its agonist, 6-n-octylaminouracil (6-OAU), potentiates pro-inflammatory phenotype via the enhanced STAT1 pathway. Moreover, 6-OAU treatment significantly retards tumor growth and increases the anti-tumor efficacy of anti-PD-1 therapy. CONCLUSION: Overall, we report a previously unappreciated fatty acid receptor, GPR84, that serves as an important metabolic sensing switch for orchestrating anti-tumorigenic macrophage polarization. Pharmacological agonists of GPR84 hold promise to reshape and reverse the immunosuppressive TME, and thereby restore responsiveness of cancer to overcome resistance to immune checkpoint blockade.

The Implications of Racialized Economic Segregation and Allostatic Load on Mortality in Patients with Breast Cancer.

BACKGROUND: The objective of this study was to examine the association between racialized economic segregation, allostatic load (AL), and all-cause mortality in patients with breast cancer. PATIENTS AND METHODS: Women aged 18+ years with stage I-III breast cancer diagnosed between 01/01/2012 and 31/12/2020 were identified in the Ohio State University cancer registry. Racialized economic segregation was measured at the census tract level using the index of concentration at the extremes (ICE). AL was calculated with biomarkers from the cardiac, metabolic, immune, and renal systems. High AL was defined as AL greater than the median. Univariable and multivariable regression analyses using restricted cubic splines examined the association between racialized economic segregation, AL, and all-cause mortality. RESULTS: Among 4296 patients, patients residing in neighborhoods with the highest racialized economic segregation (Q1 versus Q4) were more likely to be Black (25% versus 2.1%, p < 0.001) and have triple-negative breast cancer (18.2% versus 11.6%, p < 0.001). High versus low racialized economic segregation was associated with high AL [adjusted odds ratio (aOR) 1.40, 95% confidence interval (CI) 1.21-1.61] and worse all-cause mortality [adjusted hazard ratio (aHR) 1.41, 95% CI 1.08-1.83]. In dose-response analyses, patients in lower segregated neighborhoods (relative to the 95th percentile) had lower odds of high AL, whereas patients in more segregated neighborhoods had a non-linear increase in the odds of high AL. DISCUSSION: Racialized economic segregation is associated with high AL and a greater risk of all-cause mortality in patients with breast cancer. Additional studies are needed to elucidate the causal pathways and mechanisms linking AL, neighborhood factors, and patient outcomes.

An Open-Label Study of Subcutaneous CpG Oligodeoxynucleotide (PF03512676) in Combination with Trastuzumab in Patients with Metastatic HER2+ Breast Cancer.

OBJECTIVES: CpG ODN is a Toll-like receptor 9 agonist with immunotherapeutic potential for many cancer types, including aggressive breast cancers. There is strong interest in utilizing CpG ODN as an adjuvant to improve clinical efficacy of current treatments and immunogenicity of breast cancers not traditionally responsive to active immunotherapy, such as those that are human epidermal growth factor receptor 2 (HER2)-positive. This study aimed to study the efficacy and safety of combination CpG ODN plus anti-HER2 antibody trastuzumab treatment in patients with advanced/metastatic breast cancer. METHODS: This single-arm, open-label phase II clinical trial treated patients (n = 6) with advanced/metastatic HER2-positive breast cancer with weekly subcutaneous CpG ODN and trastuzumab. Patients may have received any number of prior therapies to be enrolled (most enrolled at median 1 prior line of chemotherapy). Peripheral blood was collected at baseline and weeks 2, 6, 12, and 18 for immune analyses. Six patients were enrolled and 50% achieved stable disease (SD) response. RESULTS: Median PFS was 8.3 months. Three of the six patients enrolled opted to stop treatment due to tolerability issues. Multiplex assay for cytokine measurements revealed significantly higher VEGF-D levels at week 2 compared to baseline. Peripheral blood mononuclear cells analyzed by flow cytometry showed a significant increase in monocytic MDSC between weeks 6 and 12. Patients with progressive disease tended to have higher levels of week 6 monocytic MDSC and PD-1+ T cells than patients with SD. NK cell populations did not significantly change throughout treatment. CONCLUSIONS: CpG ODN and trastuzumab treatment of metastatic HER2 + breast cancer was safe but was not tolerable for all patients. This combination did induce potentially predictive immune profile changes in treated patients with metastatic HER2 + breast cancer, the significance of which needs to be further explored.

Why was the study done? Breast cancer that has metastasized (moved outside of the breast and local lymph nodes) is currently considered incurable and can be difficult to treat. Treatments that can stimulate the immune system to recognize cancer cells have been found to be useful for many types of cancers, including some types of breast cancers. This study tested a new immune stimulator (CpG ODN) in combination with a currently on-the-market antibody treatment for breast cancer (trastuzumab). What did the researchers do? The research team enrolled patients who had metastatic breast cancer and treated them all with a combination of trastuzumab and CpG ODN for 12 weeks. These patients were monitored for any side effects/toxicity, monitored for how long their breast cancer responded to this treatment, and monitored for how long they lived after beginning this treatment. Patients also had their blood drawn at different time points to observe how their immune cells and immune proteins (e.g. cytokines) changed on treatment. What did the researchers find? The research team enrolled six patients and found that the treatment was safe and that 50% of the patients treated did not have any breast cancer growth when given CpG ODN plus trastuzumab. Looking at the immune cells in the patient blood samples, some cells that are known to decrease the immune response to cancers (myeloid-derived suppressor cells) did increase towards the end of treatment. What do the findings mean? Overall, CpG ODN and trastuzumab treatment was found to be safe and potentially effective in preventing breast cancer growth.

Racial disparities in disease-specific mortality and surgical management of patients with ductal carcinoma in situ with microinvasion.

BACKGROUND AND OBJECTIVES: Given persistent racial disparities in breast cancer outcomes, this study explores racial differences in disease-specific mortality and surgical management among patients with microinvasive ductal carcinoma in situ (DCIS-MI). METHODS: The Surveillance, Epidemiology, and End Results Program was queried for patients aged 18+ years with DCIS-MI between January 1, 2010 and December 31, 2018. The study cohort was divided into non-Hispanic Black (NHB) and non-Hispanic White (NHW) patients. Disease-specific mortality was evaluated using Cox proportional hazards models. RESULTS: A total of 3400 patients were identified, of which 569 (16.7%) were NHB and 2831 (83.3%) were NHW. Compared with NHW patients, NHB patients had more positive lymph nodes (7.6% vs. 3.9% p < 0.001). In addition, NHB women were more likely to undergo axillary lymph node dissection (6.0% vs. 3.8%, p = 0.044) and receive chemotherapy (11.8% vs. 7.2%, p < 0.001). There were no racial differences in breast surgery type (p = 0.168), reconstructive surgery (p = 0.362), or radiation therapy (p = 0.342). Overall, NHB patients had worse disease-specific mortality (adjusted hazard ratio 2.13, 95% confidence interval [CI]: 1.10-4.14) with mortality risks diverging from NHW women after 3 years (6 years rate ratio [RR] 2.12, 95% CI: 1.13-4.34; 9 years RR 2.32, 95% CI: 1.24-4.35). CONCLUSIONS: NHB women with DCIS-MI present with higher nodal disease burden and experience worse disease-specific mortality than NHW women.

Racial Disparities in Breast Cancer: from Detection to Treatment.

PURPOSE OF REVIEW: Update on current racial disparities in the detection and treatment of breast cancer. RECENT FINDINGS: Breast cancer remains the leading cause of cancer death among Black and Hispanic women. Mammography rates among Black and Hispanic women have surpassed those among White women, with studies now advocating for earlier initiation of breast cancer screening in Black women. Black, Hispanic, Asian, and American Indian and Alaskan Native women continue to experience delays in diagnosis and time to treatment. Further, racial discrepancies in receipt of guideline-concordant care, access to genetic testing and surgical reconstruction persist. Disparities in the initiation, completion, toxicity, and efficacy of chemotherapy, endocrine therapy, and targeted drug therapy remain for racially marginalized women. Efforts to evaluate the impact of race and ethnicity across the breast cancer spectrum are increasing, but knowledge gaps remain and further research is necessary to reduce the disparity gap.

BTK inhibition potentiates anti-PD-L1 treatment in murine melanoma: potential role for MDSC modulation in immunotherapy.

Myeloid-derived suppressor cells (MDSC) have been linked to loss of immune effector cell function through a variety of mechanisms such as the generation of reactive oxygen and nitrogen species and the production of inhibitory cytokines. Our group has shown that signaling through Bruton's tyrosine kinase (BTK) is important for MDSC function. Ibrutinib is an orally administered targeted agent that inhibits BTK activation and is currently used for the treatment of B cell malignancies. Using a syngeneic murine model of melanoma, the effect of BTK inhibition with ibrutinib on the therapeutic response to systemic PD-L1 blockade was studied. BTK was expressed by murine MDSC and their activation was inhibited by ibrutinib. Ibrutinib was not directly cytotoxic to cancer cells in vitro, but it inhibited BTK activation in MDSC and reduced expression of inducible nitric oxide synthase (NOS2) and production of nitric oxide. Ibrutinib treatments decreased the levels of circulating MDSC in vivo and increased the therapeutic efficacy of anti-PD-L1 antibody treatment. Gene expression profiling showed that ibrutinib decreased Cybb (NOX2) signaling, and increased IL-17 signaling (upregulating downstream targets Mmp9, Ptgs2, and S100a8). These results suggest that further exploration of MDSC inhibition could enhance the immunotherapy of advanced melanoma.PrécisInhibition of Bruton's tyrosine kinase, a key enzyme in myeloid cellular function, improves therapeutic response to an anti-PD-L1 antibody in an otherwise fairly resistant murine melanoma model.

Phase 2 study of ibrutinib in classic and variant hairy cell leukemia.

Hairy cell leukemia (HCL) is a rare B-cell malignancy, and there is a need for novel treatments for patients who do not benefit from purine analogs. Ibrutinib, an oral agent targeting Bruton tyrosine kinase in the B-cell receptor signaling pathway, is highly effective in several malignancies. Its activity in HCL was unknown, so we conducted a multisite phase 2 study of oral ibrutinib in patients with either relapsed classic or variant hairy cell leukemia. The primary outcome measure was the overall response rate (ORR) at 32 weeks, and we also assessed response at 48 weeks and best response during treatment. Key secondary objectives were characterization of toxicity and determination of progression-free survival (PFS) and overall survival (OS). Thirty-seven patients were enrolled at 2 different doses (24 at 420 mg, 13 at 840 mg). The median duration of follow-up was 3.5 years (range, 0-5.9 years). The ORR at 32 weeks was 24%, which increased to 36% at 48 weeks. The best ORR was 54%. The estimated 36-month PFS was 73% and OS was 85%. The most frequent adverse events were diarrhea (59%), fatigue (54%), myalgia (54%), and nausea (51%). Hematologic adverse events were common: anemia (43%), thrombocytopenia (41%), and neutropenia (35%). Ibrutinib can be safely administered to patients with HCL with objective responses and results in prolonged disease control. Although the initial primary outcome objective of the study was not met, the observation of objective responses in heavily pretreated patients coupled with a favorable PFS suggests that ibrutinib may be beneficial in these patients. This trial was registered at www.clinicaltrials.gov as #NCT01841723.

Short-term and long-term financial toxicity from breast cancer treatment: a qualitative study.

PURPOSE: The rising cost of breast cancer treatment has increased patients' financial burden, intensifying an already stressful treatment process. Although researchers increasingly recognize the harmful impact of medical and nonmedical costs associated with cancer treatment, understanding patients' perspectives of financial toxicity is limited. We aimed to explore the topic of financial toxicity through the lived experiences of patients with breast cancer from groups at risk of social and economic marginalization. METHODS: We conducted semi-structured interviews with 50 women with breast cancer from four specific groups: Black women, Medicaid enrollees, rural residents, and women age ≤ 40. We transcribed, coded, and analyzed the data using deductive and inductive approaches. RESULTS: Two overarching themes captured patients' experiences of financial toxicity: short-term and long-term impacts. Short-term stressors included direct medical (e.g., co-pays, premiums), nonmedical (e.g., transportation, lodging), and indirect (e.g., job loss, reduced work hours) costs. Early in their treatments, patients' focus on survival took precedence over financial concerns. However, as the treatment course progressed, fear of consequences from compounding costs of care and financial distress negatively impacted patients' lifestyles and outlooks for the future. CONCLUSION: Programs addressing financial toxicity that look beyond early-phase interventions are needed. Specifically, patients struggling with the accumulation of treatment costs and the resultant stress require ongoing support. Long-term support is especially needed for groups vulnerable to financial instability and social marginalization.

Nipple fluid for breast cancer diagnosis using the nanopore of Phi29 DNA-packaging motor.

Detection of cancer in its early stage is a challenging task for oncologists. Inflammatory breast cancer has symptoms that are similar to mastitis and can be mistaken for microbial infection. Currently, the differential diagnosis between mastitis and Inflammatory breast cancer via nipple aspirate fluid (NAF) is difficult. Here, we report a label-free and amplification-free detection platform using an engineered nanopore of the phi29 DNA-packaging motor with biomarker Galectin3 (GAL3), Thomsen-Friedenreich (TF) binding peptide as the probe fused at its C-terminus. The binding of the biomarker in NAF samples from breast cancer patients to the probe results in the connector's conformational change with a current blockage of 32 %. Utilization of dwell time, blockage ratio, and peak signature enable us to detect basal levels of biomarkers from patient NAF samples at the single-molecule level. This platform will allow for breast cancers to be resolved at an early stage with accuracy and thoroughness.

The gut connection: Intestinal permeability as a pathway from breast cancer survivors' relationship satisfaction to inflammation across treatment.

BACKGROUND: Breast cancer survivors are prone to weakened gut barriers, allowing bacteria to migrate into the blood stream. Gut permeability fuels inflammation, which, among survivors, can elevate risk for comorbid disease development, cancer recurrence, and a poor quality of life; however, survivors' satisfying relationships can provide health benefits. This longitudinal study used a conceptual model addressing how intimate relationships is associated with health through changes in gut permeability and inflammation. METHOD: Breast cancer survivors (n = 139, stages 0-IIIC) completed a baseline visit before treatment and two follow-up visits 6 and 18 months after treatment ended. Women who had an abnormal breast cancer test followed by a benign diagnosis completed visits within a comparable timeframe (noncancer patient controls; n = 69). All women completed questionnaires assessing their relationship satisfaction and provided blood samples to assess two bacterial endotoxin biomarkers, lipopolysaccharide-binding protein (LBP) and soluble CD14 (sCD14), as well as C-reactive protein (CRP) and interleukin 6 (IL-6). RESULTS: Within-person multilevel mediation analyses showed that when a survivor's relationship satisfaction was higher than usual, her own LBP and LBP/sCD14 were lower, which was associated with lower than her own average CRP and IL-6 (95% CIs [-0.0104, -0.0002]). IL-6 was also higher when older survivors, but not younger survivors, experienced higher than usual intestinal permeability (p = .001). These effects of satisfying relationships held after accounting for cancer-related and behavioral factors. Post-hoc analyses showed LBP, sCD14, and LBP/sCD14 were associated with CRP for the cancer survivors, but only LBP and LBP/sCD14 were linked to CRP among the noncancer control patients. CONCLUSION: The gut environment is a new promising candidate for understanding a relationship's long-term health impact, particularly among those with elevated health risks. Survivors may reap multiple physiological benefits from satisfying relationships.

Depression and anxiety in colorectal cancer patients: Ties to pain, fatigue, and inflammation.

OBJECTIVE: Colorectal cancer poses a significant threat to both psychological and physical health. This study examined relationships between anxiety and depressive symptoms with pain, fatigue, and inflammation among colorectal patients. METHODS: Colorectal cancer patients (n = 88, stages 0-IV) completed a laboratory-based study visit before undergoing adjuvant cancer treatment. Patients completed questionnaires assessing depressive, anxiety, pain, and fatigue symptoms. A blood sample was also collected to measure c-reactive protein (CRP). Analyses controlled for age, sex, cancer stage, body mass index (BMI), and menopause status. RESULTS: Multiple linear regression analyses showed colorectal patients with higher depressive and anxiety symptoms had greater pain, fatigue, and CRP (ps < 0.03). Approximately one-third of patients with clinically significant depressive (CESD >16) and anxiety symptoms (BAI >16) also had clinically-elevated levels of CRP (>3 mg/L) (ps = 0.02). CONCLUSION: These results extend findings from other cancer subgroups showing heightened symptom burden among patients with depression and anxiety. They also highlight the detrimental role that elevated anxiety and depressive symptoms may play in the physical and biological side effects associated with colorectal cancer.

Bruton's tyrosine kinase: an emerging targeted therapy in myeloid cells within the tumor microenvironment.

Bruton's tyrosine kinase (BTK) is a non-receptor kinase belonging to the Tec family of kinases. The role of BTK in B cell receptor signaling is well defined and is known to play a key role in the proliferation and survival of malignant B cells. Moreover, BTK has been found to be expressed in cells of the myeloid lineage. BTK has been shown to contribute to a variety of cellular pathways in myeloid cells including signaling in the NLRP3 inflammasome, receptor activation of nuclear factor-κß and inflammation, chemokine receptor activation affecting migration, and phagocytosis. Myeloid cells are crucial components of the tumor microenvironment and suppressive myeloid cells contribute to cancer progression, highlighting a potential role for BTK inhibition in the treatment of malignancy. The increased interest in BTK inhibition in cancer has resulted in many preclinical studies that are testing the efficacy of using single-agent BTK inhibitors. Moreover, the ability of tumor cells to develop resistance to single-agent checkpoint inhibitors has resulted in clinical studies utilizing BTK inhibitors in combination with these agents to improve clinical responses. Furthermore, BTK regulates the immune response in microbial and viral infections through B cells and myeloid cells such as monocytes and macrophages. In this review, we describe the role that BTK plays in supporting suppressive myeloid cells, including myeloid-derived suppressor cells (MDSC) and tumor-associated macrophages (TAM), while also discussing the anticancer effects of BTK inhibition and briefly describe the role of BTK signaling and BTK inhibition in microbial and viral infections.

Breast cancer survivors' satisfying marriages predict better psychological and physical health: A longitudinal comparison of satisfied, dissatisfied, and unmarried women.

OBJECTIVE: Breast cancer survivors who experience psychological and physical symptoms after treatment have an increased risk for comorbid disease development, reduced quality of life, and premature mortality. Identifying factors that reduce or exacerbate their symptoms may enhance their long-term health and physical functioning. This study examined how survivors' marital status and marital satisfaction-key health determinants-impacted their psychological and physical health trajectories to understand when, and for whom, marriage offers health benefits. METHODS: Breast cancer survivors (n = 209, stages 0-IIIC) completed a baseline visit before treatment and two follow-up visits 6 and 18 months after treatment ended. Women completed questionnaires assessing their marital status and satisfaction when applicable, as well as their psychological (depressive symptoms, stress) and physical (fatigue, pain) health at each visit. RESULTS: Married women-both those in satisfying and dissatisfying marriages-experienced improvements in their depressive symptoms, stress, and fatigue from pretreatment to 6- and 18-month posttreatment. Unmarried (i.e., single, divorced/separated, or widowed) women's depressive symptoms, stress, fatigue, and pain did not change over time, instead remaining elevated 6 and 18 months after treatment ended. Women in satisfying marriages also had fewer psychological and physical symptoms after treatment than those who were unmarried or in dissatisfying marriages. CONCLUSIONS: Although marriage was associated with improved psychological and physical health, the gains were most notable when survivors' marriages were satisfying. Thus, the quality of survivors' marriages, rather than the marriage itself, provided the most benefits to their psychological and physical health.

Modeling combination therapy for breast cancer with BET and immune checkpoint inhibitors.

CTLA-4 is an immune checkpoint expressed on active anticancer T cells. When it combines with its ligand B7 on dendritic cells, it inhibits the activity of the T cells. The Bromo- and Extra-Terminal (BET) protein family includes proteins that regulate the expression of key oncogenes and antiapoptotic proteins. BET inhibitor (BETi) has been shown to reduce the expression of MYC by suppressing its transcription factors and to down-regulate the hypoxic transcriptome response to VEGF-A. This paper develops a mathematical model of the treatment of cancer by combination therapy of BETi and CTLA-4 inhibitor. The model shows that the two drugs are positively correlated in the sense that the tumor volume decreases as the dose of each of the drugs is increased. The model also considers the effect of the combined therapy on levels of myeloid-derived suppressor cells (MDSCs) and the overexpression of TNF-α, which may predict gastrointestinal side effects of the combination.

Exploratory analysis of immune checkpoint receptor expression by circulating T cells and tumor specimens in patients receiving neo-adjuvant chemotherapy for operable breast cancer.

BACKGROUND: While combinations of immune checkpoint (ICP) inhibitors and neo-adjuvant chemotherapy (NAC) have begun testing in patients with breast cancer (BC), the effects of chemotherapy on ICP expression in circulating T cells and within the tumor microenvironment are still unclear. This information could help with the design of future clinical trials by permitting the selection of the most appropriate ICP inhibitors for incorporation into NAC. METHODS: Peripheral blood samples and/or tumor specimens before and after NAC were obtained from 24 women with operable BC. The expression of CTLA4, PD-1, Lag3, OX40, and Tim3 on circulating T lymphocytes before and at the end of NAC were measured using flow cytometry. Furthermore, using multi-color immunohistochemistry (IHC), the expression of immune checkpoint molecules by stromal tumor-infiltrating lymphocytes (TILs), CD8+ T cells, and tumor cells was determined before and after NAC. Differences in the percentage of CD4+ and CD8+ T cells expressing various checkpoint receptors were determined by a paired Student's t-test. RESULTS: This analysis showed decreased ICP expression by circulating CD4+ T cells after NAC, including significant decreases in CTLA4, Lag3, OX40, and PD-1 (all p values < 0.01). In comparison, circulating CD8+ T cells showed a significant increase in CTLA4, Lag3, and OX40 (all p values < 0.01). Within tumor samples, TILs, CD8+ T cells, and PD-L1/PD-1 expression decreased after NAC. Additionally, fewer tumor specimens were considered to be PD-L1/PD-1 positive post-NAC as compared to pre-NAC biopsy samples using a cutoff of 1% expression. CONCLUSIONS: This work revealed that NAC treatment can substantially downregulate CD4+ and upregulate CD8+ T cell ICP expression as well as deplete the amount of TILs and CD8+ T cells found in breast tumor samples. These findings provide a starting point to study the biological significance of these changes in BC patients. TRIAL REGISTRATION: NCT04022616.

Identification of NRAS isoform 2 overexpression as a mechanism facilitating BRAF inhibitor resistance in malignant melanoma.

Activating mutations in BRAF are found in 50% of melanomas and although treatment with BRAF inhibitors (BRAFi) is effective, resistance often develops. We now show that recently discovered NRAS isoform 2 is up-regulated in the setting of BRAF inhibitor resistance in melanoma, in both cell lines and patient tumor tissues. When isoform 2 was overexpressed in BRAF mutant melanoma cell lines, melanoma cell proliferation and in vivo tumor growth were significantly increased in the presence of BRAFi treatment. shRNA-mediated knockdown of isoform 2 in BRAFi resistant cells restored sensitivity to BRAFi compared with controls. Signaling analysis indicated decreased mitogen-activated protein kinase (MAPK) pathway signaling and increased phosphoinositol-3-kinase (PI3K) pathway signaling in isoform 2 overexpressing cells compared with isoform 1 overexpressing cells. Immunoprecipitation of isoform 2 validated a binding affinity of this isoform to both PI3K and BRAF/RAF1. The addition of an AKT inhibitor to BRAFi treatment resulted in a partial restoration of BRAFi sensitivity in cells expressing high levels of isoform 2. NRAS isoform 2 may contribute to resistance to BRAFi by facilitating PI3K pathway activation.

An IL-15-based superagonist ALT-803 enhances the NK cell response to cetuximab-treated squamous cell carcinoma of the head and neck.

Squamous cell carcinoma of the head and neck (SCCHN) is the sixth most common cancer worldwide and epidermal growth factor receptor (EGFR) is overexpressed in greater than 90% of patient tumors. Cetuximab is a monoclonal antibody that binds to EGFR and can activate immune cells, such as natural killer (NK) cells, that express receptors for the Fc (constant region) of immunoglobulin G. IL-15 (interleukin-15) is a critical factor for the development, proliferation and activation of effector NK cells. A novel IL-15 compound known as ALT-803 that consists of genetically modified IL-15 plus the IL-15 receptor alpha protein (IL15Rα) fused to the Fc portion of IgG1 has recently been developed. We hypothesized that treatment with ALT-803 would increase NK cell-mediated cytotoxicity of cetuximab-coated head and neck squamous cells. CD56+ NK cells from normal healthy donors were treated overnight with ALT-803 and tested for their ability to lyse cetuximab-coated tumor cells. Cytotoxicity was greater following NK cell ALT-803 activation, as compared to controls. ALT-803-treated NK cells secreted significantly higher levels of IFN-γ than control conditions. Additionally, NK cells showed increased levels of phospho-ERK and phospho-STAT5 when co-cultured with cetuximab-coated tumors and ALT-803. Administration of both cetuximab and ALT-803 to mice harboring Cal27 SCCHN tumors resulted in significantly decreased tumor volume when compared to controls and compared to single-agent treatment alone. Overall, the present data suggest that cetuximab treatment in combination with ALT-803 in patients with EGFR-positive SCCHN may result in significant NK cell activation and have important anti-tumor activity.

Emerging roles of and therapeutic strategies targeting BRD4 in cancer.

The Bromodomain and Extra-terminal (BET) family of proteins were first recognized as important epigenetic regulators in inflammatory processes; however, there is increasing evidence to support the notion that BET proteins also play a critical role in 'reading' chromatin and recruiting chromatin-regulating enzymes to control gene expression in a number of pathologic processes, including cancer. To this end, the mechanisms by which BET proteins regulate chromatin remodeling and promote tumor-associated inflammation have been heavily studied over the past decade. This article to review the biology of BET protein dysfunction in promoting tumor-associated inflammation and cancer progression and the application of small molecule inhibitors that target specific BET proteins, alone or in combination with immunomodulatory agents as a novel therapeutic strategy for cancer patients.