Enhancing immunotherapy using chemotherapy and radiation to modify the tumor microenvironment

PSCA-CAR T cell therapy in metastatic castration-resistant prostate cancer: a phase 1 trial

Despite recent therapeutic advances, metastatic castration-resistant prostate cancer (mCRPC) remains lethal. Chimeric antigen receptor (CAR) T cell therapies have demonstrated durable remissions in hematological malignancies. We report results from a phase 1, first-in-human study of prostate stem cell antigen (PSCA)-directed CAR T cells in men with mCRPC. The starting dose level (DL) was 100 million (M) CAR T cells without lymphodepletion (LD), followed by incorporation of LD. The primary end points were safety and dose-limiting toxicities (DLTs). No DLTs were observed at DL1, with a DLT of grade 3 cystitis encountered at DL2, resulting in addition of a new cohort using a reduced LD regimen + 100 M CAR T cells (DL3). No DLTs were observed in DL3. Cytokine release syndrome of grade 1 or 2 occurred in 5 of 14 treated patients. Prostate-specific antigen declines (>30%) occurred in 4 of 14 patients, as well as radiographic improvements. Dynamic changes indicating activation of peripheral blood endogenous and CAR T cell subsets, TCR repertoire diversity and changes in the tumor immune microenvironment were observed in a subset of patients. Limited persistence of CAR T cells was observed beyond 28 days post-infusion. These results support future clinical studies to optimize dosing and combination strategies to improve durable therapeutic outcomes. ClinicalTrials.gov identifier NCT03873805 .

The TOPK Inhibitor HI-TOPK-032 Enhances CAR T-cell Therapy of Hepatocellular Carcinoma by Upregulating Memory T Cells

Chimeric antigen receptor (CAR) T cells are emerging as an effective antitumoral therapy. However, their therapeutic effects on solid tumors are limited because of their short survival time and the immunosuppressive tumor microenvironment. Memory T cells respond more vigorously and persist longer than their naïve/effector counterparts. Therefore, promoting CAR T-cell development into memory T cells could further enhance their antitumoral effects. HI-TOPK-032 is a T-LAK cell-originated protein kinase (TOPK)-specific inhibitor that moderately represses some types of tumors. However, it is unknown whether HI-TOPK-032 works on hepatocellular carcinoma (HCC) and whether it impacts antitumoral immunity. Using both subcutaneous and orthotopic xenograft tumor models of two human HCC cell lines, Huh-7 and HepG2, we found that HI-TOPK-032 significantly improved proliferation/persistence of CD8+ CAR T cells, as evidenced by an increase in CAR T-cell counts or frequency of Ki-67+CD8+ cells and a decrease in PD-1+LAG-3+TIM-3+CD8+ CAR T cells in vivo. Although HI-TOPK-032 did not significantly suppress HCC growth, it enhanced the capacity of CAR T cells to inhibit tumor growth. Moreover, HI-TOPK-032 augmented central memory CD8+ T cell (TCM) frequency while increasing eomesodermin expression in CD8+ CAR T cells in tumor-bearing mice. Moreover, it augmented CD8+ CAR TCM cells in vitro and reduced their expression of immune checkpoint molecules. Finally, HI-TOPK-032 inhibited mTOR activation in CAR T cells in vitro and in tumors, whereas overactivation of mTOR reversed the effects of HI-TOPK-032 on CD8+ TCM cells and tumor growth. Thus, our studies have revealed mechanisms underlying the antitumoral effects of HI-TOPK-032 while advancing CAR T-cell immunotherapy.

Induction of Arterial Inflammation by Immune Checkpoint Inhibitor Therapy in Lung Cancer Patients as Measured by 2-[18F]FDG Positron Emission Tomography/Computed Tomography Depends on Pre-Existing Vascular Inflammation

BACKGROUND

Immune checkpoint inhibitors (ICI) are one of the most effective therapies in oncology, albeit associated with various immune-related adverse events also affecting the cardiovascular system.

METHODS

We aimed to investigate the effect of ICI on arterial 2-[18F]FDG uptake by using 2-[18F]FDG PET/CT imaging pre/post treatment in 47 patients with lung cancer. Maximum 2-[18F]FDG standardized uptake values (SUVmax) and target-to-background ratios (TBRs) were calculated along six arterial segments. We classified the arterial PET lesions by pre-existing active inflammation (cut-off: TBRpre ≥ 1.6). 2-[18F]FDG metabolic activity pre/post treatment was also quantified in bone marrow, spleen, and liver. Circulating blood biomarkers were additionally collected at baseline and after immunotherapy.

RESULTS

ICI treatment resulted in significantly increased arterial inflammatory activity, detected by increased TBRs, in all arterial PET lesions analyzed. In particular, a significant elevation of arterial 2-[18F]FDG uptake was only recorded in PET lesions without pre-existing inflammation, in calcified as well as in non-calcified lesions. Furthermore, a significant increase in arterial 2-[18F]FDG metabolic activity after immunotherapy was solely observed in patients not previously treated with chemotherapy or radiotherapy as well as in those without CV risk factors. No significant changes were recorded in either 2-[18F]FDG uptake of bone marrow, spleen and liver after treatment, or the blood biomarkers.

CONCLUSIONS

ICI induces vascular inflammation in lung cancer patients lacking pre-existing arterial inflammation.

The Progress and Prospects of Immune Cell Therapy for the Treatment of Cancer

Immune cell therapy as a revolutionary treatment modality, significantly transformed cancer care. It is a specialized form of immunotherapy that utilizes living immune cells as therapeutic reagents for the treatment of cancer. Unlike traditional drugs, cell therapies are considered "living drugs," and these products are currently customized and require advanced manufacturing techniques. Although chimeric antigen receptor (CAR)-T cell therapies have received tremendous attention in the industry regarding the treatment of hematologic malignancies, their effectiveness in treating solid tumors is often restricted, leading to the emergence of alternative immune cell therapies. Tumor-infiltrating lymphocytes (TIL) cell therapy, cytokine-induced killer (CIK) cell therapy, dendritic cell (DC) vaccines, and DC/CIK cell therapy are designed to use the body's natural defense mechanisms to target and eliminate cancer cells, and usually have fewer side effects or risks. On the other hand, cell therapies, such as chimeric antigen receptor-T (CAR-T) cell, T cell receptor (TCR)-T, chimeric antigen receptor-natural killer (CAR-NK), or CAR-macrophages (CAR-M) typically utilize either autologous stem cells, allogeneic or xenogeneic cells, or genetically modified cells, which require higher levels of manipulation and are considered high risk. These high-risk cell therapies typically hold special characteristics in tumor targeting and signal transduction, triggering new anti-tumor immune responses. Recently, significant advances have been achieved in both basic and clinical researches on anti-tumor mechanisms, cell therapy product designs, and technological innovations. With swift technological integration and a high innovation landscape, key future development directions have emerged. To meet the demands of cell therapy technological advancements in treating cancer, we comprehensively and systematically investigate the technological innovation and clinical progress of immune cell therapies in this study. Based on the therapeutic mechanisms and methodological features of immune cell therapies, we analyzed the main technical advantages and clinical transformation risks associated with these therapies. We also analyzed and forecasted the application prospects, providing references for relevant enterprises with the necessary information to make informed decisions regarding their R&D direction selection.

Statins abrogate gemcitabine-induced PD-L1 expression in pancreatic cancer-associated fibroblasts and cancer cells with improved therapeutic outcome

A combination of chemotherapy with immunotherapy has been proposed to have better clinical outcomes in Pancreatic Ductal Adenocarcinoma (PDAC). On the other hand, chemotherapeutics is known to have certain unwanted effects on the tumor microenvironment that may mask the expected beneficial effects of immunotherapy. Here, we have investigated the effect of gemcitabine (GEM), on two immune checkpoint proteins (PD-L1 and PD-L2) expression in cancer associated fibroblasts (CAFs) and pancreatic cancer cells (PCCs). Findings of in vitro studies conducted by using in-culture activated mouse pancreatic stellate cells (mPSCs) and human PDAC patients derived CAFs demonstrated that GEM significantly induces PD-L1 and PD-L2 expression in these cells. Moreover, GEM induced phosphorylation of STAT1 and production of multiple known PD-L1-inducing secretory proteins including IFN-γ in CAFs. Upregulation of PD-L1 in PSCs/CAFs upon GEM treatment caused T cell inactivation and apoptosis in vitro. Importantly, Statins suppressed GEM-induced PD-L1 expression both in CAFs and PCCs while abrogating the inactivation of T-cells caused by GEM-treated PSCs/CAFs. Finally, in an immunocompetent syngeneic orthotopic mouse pancreatic tumor model, simvastatin and GEM combination therapy significantly reduced intra-tumor PD-L1 expression and noticeably reduced the overall tumor burden and metastasis incidence. Together, the findings of this study have provided experimental evidence that illustrates potential unwanted side effects of GEM that could hamper the effectiveness of this drug as mono and/or combination therapy. At the same time the findings also suggest use of statins along with GEM will help in overcoming these shortcomings and warrant further clinical investigation.

Unrevealing the vital role of ncRNAs in Gastric Cancer chemoresistance

The high incidence of gastric cancer in many nations and poor overall survival rates has remained a serious global health concern. Chemoresistance in gastric cancer is a significant issue that hinders the efficacy of available treatment options. In gastric cancer, non-coding RNAs like microRNAs, long non-coding RNAs, and circular RNAs have become effective regulators of chemoresistance. These non-coding RNAs can influence several mechanisms, including drug efflux transporters, drug metabolism, and detoxification, cancer stem cells and the epithelial-mesenchymal transition, autophagy and apoptosis, and the tumor microenvironment. In this article review, we summarize the key roles non-coding RNAs play in the chemoresistance of gastric cancer and consider how they might be used in clinical settings as markers for diagnosis and prognosis, as well as potential targets and treatment plans. We also emphasize the need for additional study and collaborations in this area and highlight the difficulties and opportunities in non-coding RNA research for gastric cancer chemoresistance. This review offers crucial insights into the intricate relationship between non-coding RNAs and chemoresistance in gastric cancer, with implications for precision oncology and personalized medicine.

Efficacy and safety of immunochemotherapy, immunotherapy, chemotherapy, and targeted therapy as first-line treatment for advanced and metastatic esophageal cancer: a systematic review and network meta-analysis

Background

The treatment of esophageal cancer has entered a new phase with the development of immunotherapy. The current investigation purpose is to investigate and contrast the efficacy and safety of immunotherapy, immunochemotherapy, chemotherapy, and targeted therapy as first-line treatment for individuals suffering from advanced and metastatic esophageal cancer.

Methods

Within the framework of this systematic review and network meta-analysis, clinical trials published or reported in English up until 01 May, 2022, were retrieved from Embase, PubMed, Cochrane Central Register of Controlled Trials, the ClinicalTrials.gov databases, ESMO, and ASCO. The analysis incorporated randomized controlled trials (RCTs) from phase 2 to 3 that evaluated a minimum of two first-line therapeutic regimens for metastatic esophageal cancer were included in the analysis. The primary outcomes were overall survival (OS) and progression-free survival (PFS). Secondary clinical outcomes included the incidence of objective response rate (ORR), and adverse events (AEs) of any grade and ≥3 grade. Relative summary data were extracted from included studies by GZ, HS, WS, and TD. For clear statistical analysis, chemotherapy was divided into two categories of fluorouracil-based chemotherapy (FbCT) and fluorouracil-free chemotherapy (FfCT). Bayesian frequentist approach was employed to conduct the network meta-analysis. The indirect intercomparison between regimens was presented with league tables (HRs and 95% CI for OS and PFS, ORs and 95% CI for ORR and AEs). A greater surface value under the cumulative ranking (SUCRA) indicates a higher potential ranking for the corresponding treatment. A further calculation of relative results about esophageal squamous cell cancer was performed in the subgroup analysis. The current protocol for the systematic review has been properly registered on PROSPERO (registration number: CRD42021241145).

Findings

The final analysis comprised 17 trials that involved 9128 patients and 19 distinct treatment regimens. Within the scope of investigated immunotherapy (IO) combinations, toripalimab + FfCT (tori + FfCT) demonstrated the best OS advantages (tori + FfCT vs. FbCT, HR 0.57, 95% CI 0.38-0.85; tori + FfCT vs. FfCT, HR 0.58, 95% CI 0.43-0.78). In terms of PFS, camrelizumab + FfCT (cam + FfCT) demonstrated the best PFS advantages (FbCT vs. cam + FfCT, HR 1.79, 95% CI 1.22-2.63; FfCT vs. cam + FfCT, HR 1.79, 95% CI 1.47-2.17). Nivolumab + FbCT (nivo + FbCT vs. FfCT, OR 3.29, 95% CI 1.43-7.56) showed the best objective responses. Compared to the conventional chemotherapy regimen, the toxicity was observed to be the slightest for the tori + FfCT (FbCT vs. tori + FfCT, OR 3.07, 95% CI 1.22-7.7) and sintilimab + FfCT (FbCT vs. sin + FfCT, OR 2.93, 95% CI 1.16-7.37). The results in this study were evaluated as having a low heterogeneity since the I² value was ≤25% in all analyses.

Interpretation

Compared to foreign IO combinations, sin + FfCT, tori + FfCT, cam + FfCT, and tisle + FbCT are superior first-line treatment options for patients with advanced and metastatic esophageal cancer. Although foreign IO combinations, such as pembro + FbCT and nivo + FbCT obtained better objective response rates than other IO combinations, the addition of chemotherapy to IO worsens the safety profiles. Our findings could provide complementary evidence for current guideline recommendations.

Funding

This work was supported by a grant from the Science and Technology Program of Guangzhou, China (202206010103); and Natural Science Foundation of Guangdong Province (2022A1515012469).

Efficacy and safety of immune checkpoint inhibitor rechallenge in non-small cell lung cancer: A systematic review and meta-analysis

BACKGROUND

The aim of the study was to explore the efficacy and safety of immune checkpoint inhibitor (ICI) rechallenge in patients with non-small cell lung cancer (NSCLC).

METHODS

Studies that enrolled NSCLC patients treated with two lines of ICIs were included using four databases. The initial line (1L-) and subsequent lines (2L-) of ICIs were defined as 1L-ICI and 2L-ICI, respectively.

RESULTS

A total of 17 studies involving 2100 patients were included. The pooled objective response rate (ORR), disease control rate (DCR), median progression-free survival (mPFS), and median overall survival (mOS) for 2L-ICIs were 10%, 50%, 3.0 months, and 13.1 months, respectively. The 2L-ICI discontinuation rates caused by toxicities ranged from 0% to 23.5%. Original data were extracted from six studies, covering 89 patients. Patients in whom 1L-ICIs were discontinued following clinical decision (the mPFS of 2L-ICIs was not reach) achieved a more prolonged mPFS of 2L-ICIs than those due to toxicity (5.2 months) and progressive disease (2.1 months) (p < 0.0001). Patients' 1L-PFS for more than 2-years had preferable 2L-ORR (35.0% vs. 9.8%, p = 0.03), 2L-DCR (85.0% vs. 49.0%, p = 0.007), and 2L-mPFS (12.4 vs. 3.0 months, p < 0.0001) than those less than 1-year. Patients administered the same drugs achieved a significantly prolonged mPFS compared with the remaining patients (5.4 vs. 2.3 months, p = 0.0004), and those who did not accept antitumor treatments during the intervals of two lines of ICIs achieved a prolonged mPFS compared to those patients who did accept treatments (7.6 vs. 1.9 months, p < 0.0001).

CONCLUSIONS

ICI rechallenge is a useful therapeutic strategy for NSCLC patients, especially suitable for those who achieve long-term tumor remission for more than 2-years under 1L-ICIs.

Immunoregulation by resveratrol; implications for normal tissue protection and tumour suppression

Immune reactions are involved in both tumour and normal tissue in response to therapy. Elevated secretion of certain chemokines, exosomes and cytokines triggers inflammation, pain, fibrosis and ulceration among other normal tissue side effects. On the other hand, secretion of tumour-promoting molecules suppresses activity of anticancer immune cells and facilitates the proliferation of malignant cells. Novel anticancer drugs such as immune checkpoint inhibitors (ICIs) boost anticancer immunity via inducing the proliferation of anticancer cells such as natural killer (NK) cells and CD8+ T lymphocytes. Certain chemotherapy drugs and radiotherapy may induce anticancer immunity in the tumour, however, both have severe side effects for normal tissues through stimulation of several immune responses. Thus, administration of natural products with low side effects may be a promising approach to modulate the immune system in both tumour and normal organs. Resveratrol is a well-known phenol with diverse effects on normal tissues and tumours. To date, a large number of experiments have confirmed the potential of resveratrol as an anticancer adjuvant. This review focuses on ensuing stimulation or suppression of immune responses in both tumour and normal tissue after radiotherapy or anticancer drugs. Later on, the immunoregulatory effects of resveratrol in both tumour and normal tissue following exposure to anticancer agents will be discussed.

Prognostic and Predictive Role of Tumor-Infiltrating Lymphocytes (TILs) in Ovarian Cancer

In the last decade, tumor-infiltrating lymphocytes (TILs) have been recognized as clinically relevant prognostic markers for improved survival, providing the immunological basis for the development of new therapeutic strategies and showing a significant prognostic and predictive role in several malignancies, including ovarian cancer (OC). In fact, many OCs show TILs whose typology and degree of infiltration have been shown to be strongly correlated with prognosis and survival. The OC histological subtype with the higher presence of TILs is the high-grade serous carcinoma (HGSC) followed by the endometrioid subtype, whereas mucinous and clear cell OCs seem to contain a lower percentage of TILs. The abundant presence of TILs in OC suggests an immunogenic potential for this tumor. Despite the high immunogenic potential, OC has been described as a highly immunosuppressive tumor with a high expression of PD1 by TILs. Although further studies are needed to better define their role in prognostic stratification and the therapeutic implication, intraepithelial TILs represent a relevant prognostic factor to take into account in OC. In this review, we will discuss the promising role of TILs as markers which are able to reflect the anticancer immune response, describing their potential capability to predict prognosis and therapy response in OC.

Adoptive cell therapies in thoracic malignancies

Immunotherapy has gained great interest in thoracic malignancies in the last decade, first in non-small cell lung cancer (NSCLC), but also more recently in small-cell lung cancer (SCLC) and malignant pleural mesothelioma (MPM). However, while 15-20% of patients will greatly benefit from immune checkpoint blockers (ICBs), a vast majority will rapidly exhibit resistance. Reasons for this are multiple: non-immunogenic tumors, immunosuppressive tumor microenvironment or defects in immune cells trafficking to the tumor sites being some of the most frequent. Current progress in adoptive cell therapies could offer a way to overcome these hurdles and bring effective immune cells to the tumor site. In this review, we discuss advantages, limits and future perspectives of adoptive cell therapy (ACT) in thoracic malignancies from lymphokine-activated killer cells (LAK), cytokine-induced killer cells (CIK), natural killer cells (NK), dendritic cells (DC) vaccines and tumor-infiltrating lymphocytes (TILs) to TCR engineering and CARs. Trials are still in their early phases, and while there may still be many limitations to overcome, a combination of these different approaches with ICBs, chemotherapy and/or radiotherapy could vastly improve the way we treat thoracic cancers.

FLOT and CROSS chemotherapy regimens alter the frequency of CD27+ and CD69+ T cells in oesophagogastric adenocarcinomas: implications for combination with immunotherapy

Combining immunostimulatory chemotherapies with immunotherapy is an attractive strategy to enhance treatment responses in oesophagogastric junctional adenocarcinoma (OGJ). This study investigates the immunostimulatory properties of FLOT, CROSS and MAGIC chemotherapy regimens in the context of OGJ using in vitro and ex vivo models of the treatment-naïve and post-chemotherapy treated tumour microenvironment. FLOT and CROSS chemotherapy regimens increased surrogate markers of immunogenic cell death (HMGB1 and HLA-DR), whereas the MAGIC treatment regimen decreased HMGB1 and HLA-DR on OGJ cells (markedly for epirubicin). Tumour-infiltrating and circulating T cells had significantly lower CD27 expression and significantly higher CD69 expression post-FLOT and post-CROSS treatment. Similarly, the supernatant from FLOT- and CROSS-treated OGJ cell lines and from FLOT- and CROSS-treated OGJ biopsies cultured ex vivo also decreased CD27 and increased CD69 expression on T cells. Following 48 h treatment with post-FLOT and post-CROSS tumour conditioned media the frequency of CD69+ T cells in culture negatively correlated with the levels of soluble immunosuppressive pro-angiogenic factors in the conditioned media from ex vivo explants. Supernatant from FLOT- and CROSS-treated OGJ cell lines also increased the cytotoxic potential of healthy donor T cells ex vivo and enhanced OGJ patient-derived lymphocyte mediated-killing of OE33 cells ex vivo. Collectively, this data demonstrate that FLOT and CROSS chemotherapy regimens possess immunostimulatory properties, identifying these chemotherapy regimens as rational synergistic partners to test in combination with immunotherapy and determine if this combinatorial approach could boost anti-tumour immunity in OGJ patients and improve clinical outcomes.

How Chemotherapy Affects the Tumor Immune Microenvironment: A Narrative Review

Chemotherapy is much more effective in immunocompetent mice than in immunodeficient ones, and it is now acknowledged that an efficient immune system is necessary to optimize chemotherapy activity and efficacy. Furthermore, chemotherapy itself may reinvigorate immune response in different ways: by targeting cancer cells through the induction of cell stress, the release of damage signals and the induction of immunogenic cell death, by targeting immune cells, inhibiting immune suppressive cells and/or activating immune effector cells; and by targeting the host physiology through changes in the balance of gut microbiome. All these effects acting on immune and non-immune components interfere with the tumor microenvironment, leading to the different activity and efficacy of treatments. This article describes the correlation between chemotherapy and the immune changes induced in the tumor microenvironment. Our ultimate aim is to pave the way for the identification of the best drugs or combinations, the doses, the schedules and the right sequences to use when chemotherapy is combined with immunotherapy.

BCG invokes superior STING-mediated innate immune response over radiotherapy in a carcinogen murine model of urothelial cancer

Radiation and bacillus Calmette-Guérin (BCG) instillations are used clinically for treatment of urothelial carcinoma, but the precise mechanisms by which they activate an immune response remain elusive. The role of the cGAS-STING pathway has been implicated in both BCG and radiation-induced immune response; however, comparison of STING pathway molecules and the immune landscape following treatment in urothelial carcinoma has not been performed. We therefore comprehensively analyzed the local immune response in the bladder tumor microenvironment following radiotherapy and BCG instillations in a well-established spontaneous murine model of urothelial carcinoma to provide insight into activation of STING-mediated immune response. Mice were exposed to the oral carcinogen, BBN, for 12 weeks prior to treatment with a single 15 Gy dose of radiation or three intravesical instillations of BCG (1 × 108  CFU). At sacrifice, tumors were staged by a urologic pathologist and effects of therapy on the immune microenvironment were measured using the NanoString Myeloid Innate Immunity Panel and immunohistochemistry. Clinical relevance was established by measuring immune biomarker expression of cGAS and STING on a human tissue microarray consisting of BCG-treated non-muscle-invasive urothelial carcinomas. BCG instillations in the murine model elevated STING and downstream STING-induced interferon and pro-inflammatory molecules, intratumoral M1 macrophage and T-cell accumulation, and complete tumor eradication. In contrast, radiotherapy caused no changes in STING pathway or innate immune gene expression; rather, it induced M2 macrophage accumulation and elevated FoxP3 expression characteristic of immunosuppression. In human non-muscle-invasive bladder cancer, STING protein expression was elevated at baseline in patients who responded to BCG therapy and increased further after BCG therapy. Overall, these results show that STING pathway activation plays a key role in effective BCG-induced immune response and strongly indicate that the effects of BCG on the bladder cancer immune microenvironment are more beneficial than those induced by radiation. © 2021 The Pathological Society of Great Britain and Ireland.

Enhanced Chimeric Antigen Receptor T Cell Therapy through Co-Application of Synergistic Combination Partners

Chimeric antigen receptor (CAR) T cell therapy has achieved remarkable response rates and revolutionized the treatment of patients suffering from defined hematological malignancies. However, many patients still do not respond to this therapy or relapse after an initial remission, underscoring the need for improved efficacy. Insufficient in vivo activity, persistence, trafficking, and tumor infiltration of CAR T cells, as well as antigen escape and treatment-associated adverse events, limit the therapeutic success. Multiple strategies and approaches have been investigated to further improve CAR T cell therapy. Besides genetic modification of the CAR itself, the combination with other treatment modalities has the potential to improve this approach. In particular, combining CAR T cells with clinically approved compounds such as monoclonal antibodies and small molecule inhibitors might be a promising strategy. Combination partners could already be applied during the production process to influence the cellular composition and immunophenotype of the final CAR T cell product. Alternatively, simultaneous administration of clinically approved compounds with CAR T cells would be another feasible avenue. In this review, we will discuss current strategies to combine CAR T cells with compounds to overcome recent limitations and further enhance this promising cancer therapy, potentially broadening its application beyond hematology.

Chemotherapy after immune checkpoint inhibitor failure in metastatic melanoma: a retrospective multicentre analysis

INTRODUCTION

Despite remarkably improved outcomes with immune checkpoint inhibition, many patients with metastatic melanoma will eventually require further therapy. Chemotherapy has limited activity when used first-line but can alter the tumour microenvironment and does improve efficacy when used in combination with immunotherapy in lung cancer. Whether chemotherapy after checkpoint inhibitor failure has relevant activity in patients with metastatic melanoma is unknown.

METHODS

Patients with metastatic melanoma treated with chemotherapy after progression on immunotherapy with checkpoint inhibitors were identified retrospectively from 24 melanoma centres. Objective response rate (ORR), progression-free survival (PFS), overall survival (OS) and safety were examined.

RESULTS

In total, 463 patients were treated between 2007 and 2017. Fifty-six per cent had received PD-1-based therapy before chemotherapy. Chemotherapy regimens included carboplatin + paclitaxel (32%), dacarbazine (25%), temozolomide (15%), taxanes (9%, nab-paclitaxel 4%), fotemustine (6%) and others (13%). Median duration of therapy was 7.9 weeks (0-108). Responses included 0.4% complete response (CR), 12% partial response (PR), 21% stable disease (SD) and 67% progressive disease (PD). Median PFS was 2.6 months (2.2, 3.0), and median PFS in responders was 8.7 months (6.3, 16.3), respectively. Twelve-month PFS was 12% (95% CI 2-15%). In patients who had received anti-PD-1 before chemotherapy, the ORR was 11%, and median PFS was 2.5 months (2.1, 2.8). The highest activity was achieved with single-agent taxanes (N = 40), with ORR 25% and median PFS 3.9 months (2.1, 6.2). Median OS from chemotherapy start was 7.1 months (6.5, 8.0). Subsequent treatment with checkpoint inhibitors achieved a response rate of 16% with a median PFS of 19.1 months (2.0-43.1 months). No unexpected toxicities were observed.

CONCLUSION

Chemotherapy has a low response rate and short PFS in patients with metastatic melanoma who have failed checkpoint inhibitor therapy, although activity varied between regimens. Chemotherapy has a limited role in the management of metastatic melanoma.

The tumour immune microenvironment in oesophageal cancer

Oesophageal cancer (OC) is an inflammation-associated malignancy linked to gastro-oesophageal reflux disease, obesity and tobacco use. Knowledge of the microenvironment of oesophageal tumours is relevant to our understanding of the development of OC and its biology, and has major implications for understanding the response to standard therapies and immunotherapies, as well as for uncovering novel targets. In this context, we discuss what is known about the TME in OC from tumour initiation to development and progression, and how this is relevant to therapy sensitivity and resistance in the two major types of OC. We provide an immunological characterisation of the OC TME and discuss its prognostic implications with specific comparison with the Immunoscore and immune-hot, -cold, altered-immunosuppressed and -altered-excluded models. Targeted therapeutics for the TME under pre-clinical and clinical investigation in OCs are also summarised. A deeper understanding of the TME will enable the development of combination approaches to concurrently target the tumour cells and TME delivering precision medicine to OC patients.

Immunotherapy-Based Therapeutic Strategies for Recurrent Advanced Squamous Cell Carcinoma of the Head and Neck: A Case Report and Literature Review

We present a patient with locoregionally advanced laryngeal carcinoma, who experienced recurrence 2 months after surgery. We exploratively treated this patient with immunotherapy combined with targeted therapy with or without radiation therapy. The patient exhibited a significant and durable response. Thus far, there are no standard or effective second-line therapeutic modalities for recurrent locoregionally advanced laryngeal carcinoma. The efficacy of conventional chemotherapy with anti-epidermal growth factor receptor (anti-EGFR) remains unsatisfactory. The addition of immunotherapy resulted in substantial improvement in the progression-free survival (PFS) and overall survival (OS) of this patient. In this case, immunotherapy combined with anti-EFGR was administered, leading to good tumor response; based on this observation, radiotherapy was added to further intensify tumor control. This therapeutic strategy may be a novel option for recurrent locoregionally advanced squamous cell carcinoma of the head and neck.

Phase I Trial of Cemiplimab, Radiotherapy, Cyclophosphamide, and Granulocyte Macrophage Colony-Stimulating Factor in Patients with Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma

LESSONS LEARNED

Cemiplimab in combination with radiation therapy, cyclophosphamide, and granulocyte macrophage colony-stimulating factor did not demonstrate efficacy above what can be achieved with other PD-1 inhibitor monotherapies in patients with refractory and metastatic head and neck squamous cell carcinoma. The safety profile of cemiplimab combination therapy was consistent with previously reported safety profiles of cemiplimab monotherapy. No new safety signal was observed.

BACKGROUND

Refractory and metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) generally does not respond to PD-1 inhibitor monotherapy. Cemiplimab is a human anti-PD-1 monoclonal antibody. An expansion cohort enrolled patients with R/M HNSCC in a phase I study combining cemiplimab plus radiation therapy (RT), cyclophosphamide, and granulocyte macrophage colony-stimulating factor (GM-CSF).

METHODS

Patients with R/M HNSCC refractory to at least first-line therapy and for whom palliative RT is clinically indicated received cemiplimab plus RT, cyclophosphamide, and GM-CSF. The co-primary objectives were the safety, tolerability, and efficacy of cemiplimab plus RT, cyclophosphamide, and GM-CSF in 15 patients with R/M HNSCC.

RESULTS

Fifteen patients were enrolled. Patients discontinued treatment due to progression of disease. The most common treatment-emergent adverse events (TEAEs) of any grade were fatigue (40.0%), constipation (26.7%), and asthenia, dyspnea, maculo-papular rash, and pneumonia (each 20%). The only grade ≥3 TEAE that occurred in two patients was pneumonia (13.3%). By investigator assessment, there was one partial response (6.7%); disease control rate was 40.0% (95% confidence interval [CI], 16.3-67.7; five patients with stable disease); seven patients had progressive disease, and two were not evaluable. Median progression-free survival by investigator assessment was 1.8 months (95% CI, 1.7-4.7).

CONCLUSION

The regimen demonstrated tolerability but not efficacy above that which can be achieved with anti-PD-1 inhibitor monotherapy for R/M HNSCC.

Point-source burst of coordination polymer nanoparticles for tri-modality cancer therapy

Cancer immunotherapy, particularly the inhibition of immune checkpoints with neutralizing antibodies, has revolutionized the treatment of some cancer patients. However, immune checkpoint blockade has not provided survival benefits to most patients with colorectal and ovarian cancers. This work reports the design of acid-sensitive core-shell nanoscale coordination polymer particles (NCP) comprising a carboplatin prodrug and an siRNA against PD-L1 (siPD-L1) in the core and digitoxin on the shell for tri-modality cancer therapy. Upon cellular uptake, NCP particles rapidly burst in acidic organelles to release carboplatin for apoptosis, digitoxin for inducing immunogenicity, and siPD-L1 for PD-L1 knockdown. With long blood circulation and high tumor accumulation, NCP particles efficiently suppress the growth and metastasis of syngeneic cancers through reactivating innate and adaptive immune responses. NCP particles thus provide a promising platform to synergistically combine chemotherapy and immunotherapy for the treatment of advanced and aggressive cancers.

Adjuvant Antitumor Immunity Contributes to the Overall Antitumor Effect of Pegylated Liposomal Doxorubicin (Doxil®) in C26 Tumor-Bearing Immunocompetent Mice

Doxorubicin (DXR) has been reported to have direct cytotoxicity against cancer cells and indirect immunotoxicity by modulation of host antitumor immunity. Hence, it may prevent cancer progression by a dual mechanism. Doxil^®, a formulation of DXR encapsulated in polyethylene glycol modified (PEGylated) liposomes, is the most widely used of the clinically approved liposomal anticancer drugs. However, the effect of Doxil^® on host antitumor immunity is not well understood. In this study, Doxil^® efficiently suppressed tumor growth in immunocompetent mice bearing C26 murine colorectal carcinomas, but not in T cell-deficient nude mice, indicating a contribution of T cells to the overall antitumor effect of Doxil^®. In immunocompetent mice, Doxil^® increased major histocompatibility complex (MHC-1) levels in C26 tumors, which may be an indicator of increased immunogenicity of tumor cells, and potentially amplified tumor immunogenicity by decreasing immunosuppressive cells such as regulatory T cells, tumor-associated microphages and myeloid-derived suppressor cells that collectively suppress T cell-mediated antitumor responses. This suggests that encapsulation of DXR into PEGylated liposomes increased the therapeutic efficacy of DXR though effects on host antitumor immunogenicity in addition to direct cytotoxic effects on tumor cells. This report describes the role of host antitumor immunity in the overall therapeutic effects of Doxil^®. Manipulating pharmacokinetics and biodistribution of chemotherapeutic agents with immunomodulatory properties may increase their therapeutic efficacies by amplifying host antitumor immunity in addition to direct cytotoxic effects on tumor cells.

Programming CAR T cells to enhance anti-tumor efficacy through remodeling of the immune system

Chimeric antigen receptor (CAR) T cells have been indicated effective in treating B cell acute lymphoblastic leukemia and non-Hodgkin lymphoma and have shown encouraging results in preclinical and clinical studies. However, CAR T cells have achieved minimal success against solid malignancies because of the additional obstacles of their insufficient migration into tumors and poor amplification and persistence, in addition to antigen-negative relapse and an immunosuppressive microenvironment. Various preclinical studies are exploring strategies to overcome the above challenges. Mobilization of endogenous immune cells is also necessary for CAR T cells to obtain their optimal therapeutic effect given the importance of the innate immune responses in the elimination of malignant tumors. In this review, we focus on the recent advances in the engineering of CAR T cell therapies to restore the immune response in solid malignancies, especially with CAR T cells acting as cellular carriers to deliver immunomodulators to tumors to mobilize the endogenous immune response. We also explored the sensitizing effects of conventional treatment approaches, such as chemotherapy and radiotherapy, on CAR T cell therapy. Finally, we discuss the combination of CAR T cells with biomaterials or oncolytic viruses to enhance the anti-tumor outcomes of CAR T cell therapies in solid tumors.

The impact of immunotherapy on the survival of pancreatic adenocarcinoma patients who do not receive definitive surgery of the tumor

Background and Purpose

Immunotherapy has shown great efficacy in many cancers, but its role in pancreatic ductal adenocarcinoma (PDAC) remains unclear. The objective of this study was to investigate the impact of immunotherapy on the overall survival of PDAC patients who did not receive definitive surgery of the pancreatic primary tumor site using the National Cancer Database (NCDB).

Materials and Methods

Patients with pancreatic adenocarcinoma who did not receive surgery were identified from NCDB. Cox proportional hazard models were employed to assess the impact of immunotherapy on survival after adjusting for age at diagnosis, race, sex, place of living, income, education, treatment facility type, insurance status, year of diagnosis, and treatment types such as chemotherapy and radiation therapy.

Results

Of 263,886 patients who were analyzed, 911 (0.35%) received immunotherapy. Among patients who received chemotherapy (101,546), and chemoradiation (30,226) therapy, 555/101,546 (0.55%) received chemotherapy plus immunotherapy, and 299/3,022 (9.9%) received chemoradiation plus immunotherapy. In a multivariable analysis adjusted for the factors mentioned above, immunotherapy was associated with significantly improved OS (HR: 0.866 (0.800–0.937); P < 0.001) compared to no immunotherapy. Chemotherapy plus immunotherapy was significantly associated with improved OS (HR: 0.848 (0.766–0.938); P < 0.001) compared to chemotherapy without immunotherapy. Further, chemoradiation plus immunotherapy was associated with significantly improved OS (HR: 0.813 (0.707–0.936); P < 0.001) compared to chemoradiation alone.

Conclusion

In this study, the addition of immunotherapy to chemotherapy and chemoradiation therapy was associated with significantly improved OS in PDAC patients without definitive surgery. The study warrants future clinical trials of immunotherapy in PDAC.

The impact of immunotherapy on the survival of pancreatic adenocarcinoma patients who received definitive surgery of the pancreatic tumor: a retrospective analysis of the National Cancer Database

BACKGROUND

Immunotherapy has paved the way for new therapeutic opportunities in cancer but has failed to show any efficacy in Pancreatic Adenocarcinoma (PDAC), and its therapeutic role remains unclear. The objective of this study is to examine the impact of immunotherapy in combination with chemotherapy, RT, and chemoradiation on the overall survival (OS) of PDAC patients who received definitive surgery of the tumor using the National Cancer Database (NCDB).

METHODS

Patients with PDAC who received definitive surgery of the pancreatic tumor and were diagnosed between 2004 and 2016 from the NCDB were identified. Cox proportional hazard analysis was used to assess the survival difference between patients who received chemotherapy plus immunotherapy and chemoradiation therapy plus immunotherapy and their counterparts who only receive these treatments without immunotherapy. The multivariable analysis was adjusted for age of diagnosis, race, sex, place of living, income, education, treatment facility type, insurance status, year of diagnosis, and treatment types such as chemotherapy and radiation therapy.

RESULTS

In total, 63,154 PDAC patients who received definitive surgery of the tumor were included in the analysis. Among the 63,154 patients, 636 (1.01%) received immunotherapy. Among patients who received chemotherapy (21,355), and chemoradiation (21,875), 157/21,355 (0.74%) received chemotherapy plus immunotherapy, and 451/21,875 (2.06%) received chemoradiation plus immunotherapy. Patients who received chemoradiation plus immunotherapy had significantly improved median OS compared to patients who only received chemoradiation with an absolute median OS benefit of 5.7 [29.31 vs. 23.66, p < 0.0001] months. In the multivariable analysis, patients who received immunotherapy had significantly improved OS compared to patients who did not receive immunotherapy (HR: 0.900; CI: 0.814-0.995; P < 0.039). Patients who received chemoradiation plus immunotherapy had significantly improved OS compared to their counterparts who only received chemoradiation without immunotherapy (HR: 0.852 CI: 0.757-0.958; P < 0.008).

CONCLUSIONS

In this study, the addition of immunotherapy to chemoradiation therapy was associated with significantly improved OS in PDAC patients who received definitive surgery. The study warrants further future clinical trials of immunotherapy in PDAC.

Cardamonin induces immune responses and enhances survival rate in WEHI-3 cell-generated mouse leukemia in vivo

Cardamonin, a monomeric alkaloid, is isolated from Alpinia conchigera Griff and other natural plants. Recently, it has been focused on its anticancer activities, and no information showing its immune effects on leukemia mice was reported. In this study, we investigated the immune effects of cardamonin on WEHI-3 cell-generated leukemia mice. Forty BALB/c mice were randomly divided into four groups: Group I mice were normal animals and groups II-IV were leukemia. Group II mice, as a positive control, were administered with normal diet, and group III and IV mice were treated with 1 and 5 mg/kg of cardamonin, respectively, by intraperitoneal injection every 2 days for 14 days. The population of white blood cells, macrophage phagocytosis, and the proliferations of T and B cells were analyzed by flow cytometry. Another forty mice were also separated randomly into four groups for the determination of survival rate. Results showed that cardamonin did not affect body weight. Cardamonin decreased CD3, CD11b, and Mac-3 cell populations but increased CD19 number. Cardamonin enhanced phagocytic abilities of macrophages from the peripheral blood mononuclear cells of leukemia mice. Furthermore, cardamonin at 1 mg/kg treatment improved the survival rate of leukemia mice in vivo. Therefore, cardamonin could be applied for a leukemia therapeutic reagent at a defined dose.

Is single versus combination therapy problematic in the treatment of cutaneous melanoma?

Introduction: The development of immunotherapies and targeted therapies has changed the treatment approach in resectable, nonresectable, and metastatic melanoma. Because of their different pharmacological profiles, immunotherapies and/or targeted therapies have been studied in various combinations. Areas covered: We reviewed PubMed for most important clinical trials investigating efficacy and tolerability of combinatorial and single-agent approaches for the treatment of melanoma that were published up to June 2019. We discuss the most promising therapy approaches and highlight challenges of melanoma treatment. Expert opinion: Combinatorial approaches seem to be very promising in the treatment of resectable and advanced melanoma. Currently, dual immune checkpoint inhibition (ICI) with nivolumab and ipilimumab offers the best first-line treatment option for patients with BRAF-wt and -mutated, advanced melanoma. It is therapy of choice in younger patients with good ECOG performance status and poor prognostic features, whereas ICI monotherapy should be preferred in elderly patients with advanced melanoma. Benefit-risk ratio, patient's QoL and expectations, as well as treatment costs have to be considered in the choice of treatment. However, to elucidate mechanisms of resistance, biomarkers of response and to better define personalized strategies in the treatment of cutaneous melanoma, larger clinical trials comparing combined versus sequential therapies are necessary.

Prognostic significance of PD-L1 expression on cell-surface vimentin-positive circulating tumor cells in gastric cancer patients

Although circulating tumor cells (CTCs) have shown promise as potential biomarkers for diagnostic and prognostic assessment in gastric cancer (GC), determining the predictive and prognostic value of programmed death‐ligand 1 (PD‐L1)‐positive CTCs in patients with GC is a challenge. Here, we identified that the expression of total vimentin (VIM) protein was positively correlated with PD‐L1 and inhibited CD8⁺ T‐cell activation in patients with GC according to bioinformatics analysis. Notably, coexpression of PD‐L1 and cell‐surface VIM (CSV) was detected by immunofluorescence and immunohistochemistry assay in locally advanced GC tumor specimens and metastatic lymph nodes. Likewise, CSV expression level was significantly decreased after transiently knocking down PD‐L1 in GC cell lines. Based on our established CTC detection platform, CTCs were isolated from peripheral blood samples collected from 70 patients (38 resectable and 32 unresectable) with GC using magnetic positive selection and a CSV‐specific monoclonal antibody, 84‐1. CSV⁺PD‐L1⁺CTCs were observed in 50 of 70 (71%) GC patient samples, ranging from 0 to 261 mL⁻¹. A higher number of CSV⁺PD‐L1⁺CTCs were significantly associated with a short survival duration and poor therapeutic response. This study demonstrated that detection of PD‐L1⁺CTCs using a CSV‐enrichment method has promising value as a clinically relevant prognostic marker for GC.

Co-expression of HLA-I loci improved prognostication in HER2+ breast cancers

The underlying basis for cancer immune evasion is important for effective immunotherapy and prognosis in breast cancers. Human leucocyte antigens (HLA)-I comprising three classical antigens (HLA-A, -B and -C) is mandatory for anti-tumor immunity. Its loss occurred frequently in many cancers resulting in effective immune evasion. Most studies examined HLA-I as a whole. Alterations in specific locus could have different clinical ramifications. Hence, we evaluated the expression of the three HLA-I loci in a large cohort of breast cancers. Low expression of HLA-A, -B and -C were found in 71.1%, 66.3%, and 60.2% of the cases. Low and high expression in all loci was found in 48.3% and 17.9% of the cases respectively. The remaining showed high expression in one or two loci. Cases with all HLA high expression (all HLA high) was frequent in the ER-HER2- (27.4%) and ER-HER2+ (23.1%) cases and was associated with characteristic pathologic features related to these tumor (higher grade, necrosis, high tumor infiltrating lymphocyte (TIL), pT stage, low hormonal receptor, high basal marker expression) (p ≤ 0.019). Interestingly, in HER2+ cancers, only cases with all HLA high and high TIL showed significantly better survival. In node positive cancers, concordant high HLA expression in primary tumors and nodal metastases was favorable prognostically (DFS: HR = 0.741, p < 0.001; BCSS: HR = 0.699, p = 0.003). The data suggested an important clinical value of a combined analysis on the co-expression HLA-I status in both primary and metastatic tumors. This could be a potential additional key component to be incorporated into TIL evaluation for improved prognostication.

Low Dose Cyclophosphamide Modulates Tumor Microenvironment by TGF-β Signaling Pathway

The tumor microenvironment has been recently recognized as a critical contributor to cancer progression and anticancer therapy-resistance. Cyclophosphamide (CTX) is a cytotoxic agent commonly used in clinics for the treatment of cancer. Previous reports demonstrated that CTX given at low continuous doses, known as metronomic schedule, mainly targets endothelial cells and circulating Tregs with unknown mechanisms. Here, we investigated the antitumor activity of two different metronomic schedules of CTX along with their corresponding MTD regimen and further explored their effect on immune function and tumor microenvironment. Toxicity evaluation was monitored by overall survival rate, weight loss, and histopathological analysis. A nude mouse model of Lewis lung cancer was established to assess the anti-metastatic effects of CTX in vivo. CD4⁺, CD8⁺, and CD4⁺CD25⁺FoxP3 T cells were selected by flow cytometry analysis. Low and continuous administration of CTX was able to restore immune function via increase of CD4⁺/CD8⁺ T cells and depletion of T regulatory cells, not only in circulatory and splenic compartments, but also at the tumor site. Low-dose CTX also reduced myofibroblasts, accompanied with an increased level of E-cadherin and low N-cadherin, both in the primary tumor and lung through the TGF-β pathway by the downregulated expression of TGF-β receptor 2. Our data may indicate that several other molecular mechanisms of CTX for tumor may be involved in metronomic chemotherapy, besides targeting angiogenesis and regulatory T cells.

Trained Immunity for Personalized Cancer Immunotherapy: Current Knowledge and Future Opportunities

Memory formation, guided by microbial ligands, has been reported for innate immune cells. Epigenetic imprinting plays an important role herein, involving histone modification after pathogen-/danger-associated molecular patterns (PAMPs/DAMPs) recognition by pattern recognition receptors (PRRs). Such "trained immunity" affects not only the nominal target pathogen, yet also non-related targets that may be encountered later in life. The concept of trained innate immunity warrants further exploration in cancer and how these insights can be implemented in immunotherapeutic approaches. In this review, we discuss our current understanding of innate immune memory and we reference new findings in this field, highlighting the observations of trained immunity in monocytic and natural killer cells. We also provide a brief overview of trained immunity in non-immune cells, such as stromal cells and fibroblasts. Finally, we present possible strategies based on trained innate immunity that may help to devise host-directed immunotherapies focusing on cancer, with possible extension to infectious diseases.

T-Regulatory Cells In Tumor Progression And Therapy

Regulatory T cells (Tregs) are important members of the immune system regulating the host responses to infection and neoplasms. Tregs prevent autoimmune disorders by protecting the host-cells from an immune response, related to the peripheral tolerance. However, tumor cells use Tregs as a shield to protect themselves against anti-tumor immune response. Thus, Tregs are a hurdle in achieving the complete potential of anti-cancer therapies including immunotherapy. This has prompted the development of novel adjuvant therapies that obviate their negative effects thereby enhancing the therapeutic efficacy. Our earlier studies have shown the efficacy of the glycolytic inhibitor, 2-deoxy-D-glucose (2-DG) by reducing the induced Tregs pool and enhance immune stimulation as well as local tumor control. These findings have suggested its potential for enhancing the efficacy of immunotherapy, besides radiotherapy and chemotherapy. This review provides a brief account of the current status of Tregs as a component of the immune-biology of tumors and various preclinical and clinical strategies pursued to obviate the limitations imposed by them in achieving therapeutic efficacy.

Combining Doxorubicin-Loaded PEGylated Poly(Lactide-co-glycolide) Nanoparticles with Checkpoint Inhibition Safely Enhances Therapeutic Efficacy in a Melanoma Model

Doxorubicin (DOX) has been widely used for the treatment of various cancers, however, the use of soluble DOX is limited by its low therapeutic index and improved formulations are therefore sought. Aside from its tumoricidal properties, DOX has also been shown to cause an immunogenic form of cell death, however, it is becoming abundantly clear that in situ immune stimulation alone is insufficient to cause significant immune based antitumor activity and that immune checkpoint modulation is also required. In this study, DOX-loaded nanoparticles were made by nanoprecipitation of DOX with a PEGylated poly(lactide-co-glycolide) copolymer (DOX-PLGA-PEG NPs) and were then tested in combination with immune checkpoint blockade (antiprogrammed death (anti-PD-1)) in a murine melanoma model to enhance antitumor effectiveness. Results showed the prepared particles to be approximately 134 nm in diameter (zeta potential -22 mV) with a loading of 1.75 μg DOX/mg NPs. In vitro release studies (of DOX) revealed the NPs to exhibit a 12 h burst release phase, followed by a slower release phase for up to 200 h. Survival studies of mice challenged with B16.F10 melanoma cells, revealed 60% of mice treated with the combination of DOX-PLGA-PEG NPs plus anti-PD-1 were tumor-free at the completion of the study. This combination therapy demonstrated higher antitumor efficacy in vivo compared to control, soluble DOX, and monotherapy of DOX-PLGA-PEG NPs or anti-PD-1 solution (p < 0.05). Moreover, in vivo safety studies (mouse weight/histopathological/toxicity) were investigated and results suggested that the combination therapy was safe. In conclusion, this study demonstrates the successful fabrication of DOX-loaded NPs by a nanoprecipitation method, and when combined with checkpoint inhibition could provide significant therapy in a murine melanoma model, suggesting that the DOX-PLGA-PEG NPs may be generating immune stimulation in situ and that benefit from this combination may be obtained in a clinical setting in the future.

Immune microenvironment modulation unmasks therapeutic benefit of radiotherapy and checkpoint inhibition

BACKGROUND

Immune checkpoint inhibitors (ICIs) for solid tumors, including those targeting programmed cell death 1 (PD-1) and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), have shown impressive clinical efficacy, however, most patients do not achieve durable responses. One major therapeutic obstacle is the immunosuppressive tumor immune microenvironment (TIME). Thus, we hypothesized that a strategy combining tumor-directed radiation with TIME immunomodulation could improve ICI response rates in established solid tumors.

METHODS

Using a syngeneic mouse model of human papillomavirus (HPV)-associated head and neck cancer, mEER, we developed a maximally effective regimen combining PD-1 and CTLA-4 inhibition, tumor-directed radiation, and two existing immunomodulatory drugs: cyclophosphamide (CTX) and a small-molecule inducible nitric oxide synthase (iNOS) inhibitor, L-n6-(1-iminoethyl)-lysine (L-NIL). We compared the effects of the various combinations of this regimen on tumor growth, overall survival, establishment of immunologic memory, and immunologic changes with flow cytometry and quantitative multiplex immunofluorescence.

RESULTS

We found PD-1 and CTLA-4 blockade, and radiotherapy alone or in combination, incapable of clearing established tumors or reversing the unfavorable balance of effector to suppressor cells in the TIME. However, modulation of the TIME with cyclophosphamide (CTX) and L-NIL in combination with dual checkpoint inhibition and radiation led to rejection of over 70% of established mEER tumors and doubled median survival in the B16 melanoma model. Anti-tumor activity was CD8+ T cell-dependent and led to development of immunologic memory against tumor-associated HPV antigens. Immune profiling revealed that CTX/L-NIL induced remodeling of myeloid cell populations in the TIME and tumor-draining lymph node and drove subsequent activation and intratumoral infiltration of CD8+ effector T cells.

CONCLUSIONS

Overall, this study demonstrates that modulation of the immunosuppressive TIME is required to unlock the benefits of ICIs and radiotherapy to induce immunologic rejection of treatment-refractory established solid tumors.

Synergistic antitumor effect of anti-PD-L1 combined with oxaliplatin on a mouse tumor model

Oxaliplatin (OXP) can change tumor microenvironment from immune-suppressive toward the immune-favorable condition. Almost all of the antitumor agents cannot totally cure cancer as monotherapy. So the current focus of cancer research became combining therapy using different treatment regimen, especially chemotherapy with checkpoint blockers. In this study, we assessed the activity of combining regimen using anti-PD-L1 with OXP in CT26 tumor-bearing BALB/c mice. We further analyzed the immune cell phenotypes in tumor site, lymph nodes, and spleen by flow cytometry analysis. Our study showed that combination therapy with OXP and anti-PD-L1 significantly increased survival in vivo and inhibited tumor growth of tumor-bearing mice. Inconsistent with better antitumor activity, our combination therapy led to an increase in tumor-infiltrating activated CD8+ T cells. In draining lymph nodes and spleen, regulatory T cells decreased significantly. Mice receiving either anti-PD-L1 or OXP alone had a larger tumor and lower survival rate in comparison with combination therapy receiving group. The time and order of administration of each component of the combination therapy affected antitumor response.

Enhancing Dendritic Cell Therapy in Solid Tumors with Immunomodulating Conventional Treatment

Dendritic cells (DCs) are the most potent antigen-presenting cells and are the key initiator of tumor-specific immune responses. These characteristics are exploited by DC therapy, where DCs are ex vivo loaded with tumor-associated antigens (TAAs) and used to induce tumor-specific immune responses. Unfortunately, clinical responses remain limited to a proportion of the patients. Tumor characteristics and the immunosuppressive tumor microenvironment (TME) of the tumor are likely hampering efficacy of DC therapy. Therefore, reducing the immunosuppressive TME by combining DC therapy with other treatments could be a promising strategy. Initially, conventional cancer therapies, such as chemotherapy and radiotherapy, were thought to specifically target cancerous cells. Recent insights indicate that these therapies additionally augment tumor immunity by targeting immunosuppressive cell subsets in the TME, inducing immunogenic cell death (ICD), or blocking inhibitory molecules. Therefore, combining DC therapy with registered therapies such as chemotherapy, radiotherapy, or checkpoint inhibitors could be a promising treatment strategy to improve the efficacy of DC therapy. In this review, we evaluate various clinical applicable combination strategies to improve the efficacy of DC therapy.

Bioengineered Nanocage from HBc Protein for Combination Cancer Immunotherapy

Protein nanocages are promising multifunctional platforms for nanomedicine owing to the ability to decorate their surfaces with multiple functionalities through genetic and/or chemical modification to achieve desired properties for therapeutic and diagnostic purposes. Here, we describe a model antigen (OVA peptide) that was conjugated to the surface of a naturally occurring hepatitis B core protein nanocage (HBc NC) by genetic modification. The engineered OVA-HBc nanocages (OVA-HBc NCs), displaying high density repetitive array of epitopes in a limited space by self-assembling into symmetrical structure, not only can induce bone marrow derived dendritic cells (BMDC) maturation effectively but also can be enriched in the draining lymph nodes. Naïve C57BL/6 mice immunized with OVA-HBc NCs are able to generate significant and specific cytotoxic T lymphocyte (CTL) responses. Moreover, OVA-HBc NCs as a robust nanovaccine can trigger preventive antitumor immunity and significantly delay tumor growth. When combined with a low-dose chemotherapy drug (paclitaxel), OVA-HBc NCs could specifically inhibit progression of an established tumor. Our findings support HBc-based nanocages with modularity and scalability as an attractive nanoplatform for combination cancer immunotherapy.

Compound-therapy based on cancer-immunity cycle: promising prospects for antitumor regimens

Immunotherapy has made a significant impact on the survival of patients with different tumor. However, it has become clear that they are not sufficiently active durable responses for many tumor patients, but only in a fraction of tumor patients. In order to improve this, combination regimens revealed impressive synergistic effects by combination of doublet or triplet immune agents. In this article, we will summarize the cancer-immunity cycle (CIC) and propose a rationale for the design of synergistic antitumor combinations. In addition, key issues in the development of these strategies are further discussed. Overall, we wish to highlight the backbone principles of combination regimens design at different points of the CIC, with the ultimate goal to guide better designs for future cancer combination therapies.

Synchrotron microbeam radiotherapy evokes a different early tumor immunomodulatory response to conventional radiotherapy in EMT6.5 mammary tumors

BACKGROUND

Synchrotron microbeam radiation therapy (MRT) is a new, evolving form of radiotherapy that has potential for clinical application. Several studies have shown in preclinical models that synchrotron MRT achieves equivalent tumor control to conventional radiotherapy (CRT) but with significantly reduced normal tissue damage.

METHODS

To explore differences between these two modalities, we assessed the immune cell infiltrate into EMT6.5 mammary tumors after CRT and MRT.

RESULTS

CRT induced marked increases in tumor-associated macrophages and neutrophils while there were no increases in these populations following MRT. In contrast, there were higher numbers of T cells in the MRT treated tumors. There were also increased levels of CCL2 by immunohistochemistry in tumors subjected to CRT, but not to MRT. Conversely, we found that MRT induced higher levels of pro-inflammatory genes in tumors than CRT.

CONCLUSION

Our data are the first to demonstrate substantial differences in macrophage, neutrophil and T cell numbers in tumors following MRT versus CRT, providing support for the concept that MRT evokes a different immunomodulatory response in tumors compared to CRT.

Combination Strategies to Optimize Efficacy of Dendritic Cell-Based Immunotherapy

Dendritic cells (DCs) are antigen-presenting cells (APCs) that are essential for the activation of immune responses. In various malignancies, these immunostimulatory properties are exploited by DC-therapy, aiming at the induction of effective anti-tumor immunity by vaccination with ex vivo antigen-loaded DCs. Depending on the type of DC-therapy used, long-term clinical efficacy upon DC-therapy remains restricted to a proportion of patients, likely due to lack of immunogenicity of tumor cells, presence of a stromal compartment, and the suppressive tumor microenvironment (TME), thereby leading to the development of resistance. In order to circumvent tumor-induced suppressive mechanisms and unleash the full potential of DC-therapy, considerable efforts have been made to combine DC-therapy with chemotherapy, radiotherapy or with checkpoint inhibitors. These combination strategies could enhance tumor immunogenicity, stimulate endogenous DCs following immunogenic cell death, improve infiltration of cytotoxic T lymphocytes (CTLs) or specifically deplete immunosuppressive cells in the TME, such as regulatory T-cells and myeloid-derived suppressor cells. In this review, different strategies of combining DC-therapy with immunomodulatory treatments will be discussed. These strategies and insights will improve and guide DC-based combination immunotherapies with the aim of further improving patient prognosis and care.

Curcumin as an anti-inflammatory agent: Implications to radiotherapy and chemotherapy

Cancer is the second cause of death worldwide. Chemotherapy and radiotherapy are the most common modalities for the treatment of cancer. Experimental studies have shown that inflammation plays a central role in tumor resistance and the incidence of several side effects following both chemotherapy and radiotherapy. Inflammation resulting from radiotherapy and chemotherapy is responsible for adverse events such as dermatitis, mucositis, pneumonitis, fibrosis, and bone marrow toxicity. Chronic inflammation may also lead to the development of second cancer during years after treatment. A number of anti-inflammatory drugs such as nonsteroidal anti-inflammatory agents have been proposed to alleviate chronic inflammatory reactions after radiotherapy or chemotherapy. Curcumin is a well-documented herbal anti-inflammatory agents. Studies have proposed that curcumin can help management of inflammation during and after radiotherapy and chemotherapy. Curcumin targets various inflammatory mediators such as cyclooxygenase-2, inducible nitric oxide synthase, and nuclear factor κB (NF-κB), thereby attenuating the release of proinflammatory and profibrotic cytokines, and suppressing chronic production of free radicals, which culminates in the amelioration of tissue toxicity. Through modulation of NF-κB and its downstream signaling cascade, curcumin can also reduce angiogenesis, tumor growth, and metastasis. Low toxicity of curcumin is linked to its cytoprotective effects in normal tissues. This protective action along with the capacity of this phytochemical to sensitize tumor cells to radiotherapy and chemotherapy makes it a potential candidate for use as an adjuvant in cancer therapy. There is also evidence from clinical trials suggesting the potential utility of curcumin for acute inflammatory reactions during radiotherapy such as dermatitis and mucositis.

Autophagosome-based strategy to monitor apparent tumor-specific CD8 T cells in patients with prostate cancer

The immune system plays an essential role in eradicating cancer in concert with various treatment modalities. In the absence of autologous tumor material, no standardized method exists to assess T cell responses against the many antigens that may serve as cancer rejection antigens. Thus, development of methods to screen for therapy-induced anti-tumor responses is a high priority that could help tailor therapy. Here we tested whether a tumor-derived antigen source called DRibbles®, which contain a pool of defective ribosomal products (DRiPs), long-lived and short-lived proteins (SLiPs) and danger-associated molecular patterns (DAMPs), can be used to identify tumor-associated antigen (TAA)-specific responses in patients before or after immunotherapy treatment. Protein content, gene expression and non-synonymous - single nucleotide variants (ns-SNVs) present in UbiLT3 DRibbles were compared with prostate adenocarcinomas and the prostate GVAX vaccine cell lines (PC3/LNCaP). UbiLT3 DRibbles were found to share proteins, as well as match tumor sequences for ns-SNVs with prostate adenocarcinomas and with the cell lines PC3 and LNCaP. UbiLT3 DRibbles were used to monitor anti-tumor responses in patients vaccinated with allogeneic prostate GVAX. UbiLT3-DRibble-reactive CD8+ T-cell responses were detected in post-vaccine PBMC of 6/12 patients (range 0.85-22% of CD8+ cells) after 1 week in vitro stimulation (p = 0.007 vs. pre-vaccine). In conclusion, a cancer-derived autophagosome-enriched preparation, packaging over 100 proteins over-expressed in prostate cancer into microvesicles containing DAMPs, could be used to identify CD8+ T cells in peripheral blood from patients after prostate GVAX vaccination and may represent a general method to monitor anti-cancer T cell responses following immunotherapy.

Immunotherapy in Head and Neck Squamous Cell Cancer

Prognosis in relapsed metastatic head and neck squamous cell cancer (RM-HNSCC) is dismal. Platinum based chemotherapy in combination with Cetuximab is used in first-line setting, while no further validated options are available at progression. Immunotherapy has produced durable clinical benefit in some patients with RM-HNSCC although the premises are several patients are nonresponders. Studies are ongoing to determine predictive factors and the ideal setting/combination of novel immunotherapies. In this paper, we discuss the past and present of immunotherapy in head and neck cancer and provide an up-to-date information regarding the potential ways to improve immunotherapy outcomes in HNSCC.

Immunotherapy with radiotherapy in urological malignancies

PURPOSE OF REVIEW

Radiotherapy has the potential to augment the host's immune response to cancer. Urological malignancies are highly immunogenic and the combination of radiotherapy and immunotherapy shows promise. In this review, we discuss the effects of radiotherapy on the cancer immune system and highlight the rationale for using the combined approach in prostate, urothelial and renal cancers. Current clinical studies are summarized emphasising the synergistic effects of the combination and the possibility of improved clinical outcomes.

RECENT FINDINGS

Local and abscopal effects have been observed in different urological cancers when using a combined approach. Large fraction size is associated with an increased immune response. Multiple radiotherapy/immunotherapy combinations are being studied in several clinical trials although no combination has yet been introduced in to standard practice.

SUMMARY

Although our knowledge of immunomodulation by radiotherapy has improved significantly in recent times, there remain several unanswered questions regarding how to best use the combination in clinical practice. Ongoing trials will provide further insight into complex mechanisms governing radiotherapy-immunotherapy interactions, with potential to improve clinical outcomes.

Nanoparticle co-delivery of wortmannin and cisplatin synergistically enhances chemoradiotherapy and reverses platinum resistance in ovarian cancer models

Most ovarian cancer patients respond well to initial platinum-based chemotherapy. However, within a year, many patients experience disease recurrence with a platinum resistant phenotype that responds poorly to second line chemotherapies. As a result, new strategies to address platinum resistant ovarian cancer (PROC) are needed. Herein, we report that NP co-delivery of cisplatin (CP) and wortmannin (Wtmn), a DNA repair inhibitor, synergistically enhances chemoradiotherapy (CRT) and reverses CP resistance in PROC. We encapsulated this regimen in FDA approved poly(lactic-co-glycolic acid)-poly(ethylene glycol) (PLGA-PEG) NPs to reduce systemic side effects, enhance cellular CP uptake, improve Wtmn stability, and increase therapeutic efficacy. Treatment of platinum-sensitive ovarian cancer (PSOC) and PROC murine models with these dual-drug loaded NPs (DNPs) significantly reduced tumor burden versus treatment with combinations of free drugs or single-drug loaded NPs (SNPs). These results support further investigation of this NP-based, synergistic drug regimen as a means to combat PROC in the clinic.

Differential expression of major histocompatibility complex class I in subtypes of breast cancer is associated with estrogen receptor and interferon signaling

Tumor-infiltrating lymphocytes (TILs) in triple-negative breast cancer (TNBC) have a strong prognostic and predictive significance. However, the mechanism of TIL influx in TNBC is unclear. Expression of major histocompatibility complex class I (MHC I) on the tumor cell is essential for the effective killing of tumor by cytotoxic TILs. In our current study, human leukocyte antigen (HLA) expression was inversely correlated with estrogen receptor (ER) expression in normal and cancerous breast tissue and positively correlated with TILs in breast cancer. The ER score was inversely correlated with TILs in breast cancer. HLA-A and CD8B gene expression was negatively correlated with ESR1 and positively correlated with interferon-associated gene expression in The Cancer Genome Atlas (TCGA) data. Negative correlation between ESR1 and HLA and positive correlation between interferon-associated and HLA gene expression were also confirmed in Cancer Cell Line Encyclopedia (CCLE) data. Taken together, our data suggest that a lower expression of HLA in luminal-type tumors might be associated with low level of TILs in those tumors. Further investigation of the mechanism of higher HLA expression and TIL influx in TNBC may help to boost the host immune response.

CAR-T cells and combination therapies: What's next in the immunotherapy revolution?

Cancer immunotherapies are dramatically reshaping the clinical management of oncologic patients. For many of these therapies, the guidelines for administration, monitoring, and management of associated toxicities are still being established. This is especially relevant for adoptively transferred, genetically-modified T cells, which have unique pharmacokinetic properties, due to their ability to replicate and persist long-term, following a single administration. Furthermore, in the case of CAR-T cells, the use of synthetic immune receptors may impact signaling pathways involved in T cell function and survival in unexpected ways. We, herein, comment on the most salient aspects of CAR-T cell design and clinical experience in the treatment of solid tumors. In addition, we discuss different possible scenarios for combinations of CAR-T cells and other treatment modalities, with a special emphasis on kinase inhibitors, elaborating on the strategies to maximize synergism. Finally, we discuss some of the technologies that are available to explore the molecular events governing the success of these therapies. The young fields of synthetic and systems biology are likely to be major players in the advancement of CAR-T cell therapies, providing the tools and the knowledge to engineer patients' T lymphocytes into intelligent cancer-fighting micromachines.

Adoptive transfer of natural killer cells in combination with chemotherapy improves outcomes of patients with locally advanced colon carcinoma

BACKGROUND

Despite the availability of multiple treatment strategies, patients with advanced colon carcinoma (CC) have poor prognoses. The aim of this study was to evaluate the efficacy and safety of natural killer (NK) cell therapy in combination with chemotherapy in patients with locally advanced CC.

METHODS

We assessed the cytotoxicity of NK cells to CC cells (CCs) and CC stem cells (CSCs) pre-treated with 5-fluorouracil or oxaliplatin in vitro. Then, an open-label cohort study was conducted with locally advanced CC patients who had received radical resection. Patients received either NK cell therapy combined with chemotherapy (NK cell group, 27 patients) or pure chemotherapy (control group, 33 patients). Progression-free survival (PFS), overall survival (OS) and adverse effects were investigated.

RESULTS

Chemotherapy sensitized CCs and CSCs to NK cell cytotoxicity through regulation of NK cell-activating/inhibitory receptor ligands. Poorly differentiated CCs were more susceptible to NK cells than well-differentiated ones. In the cohort study, the 5-year PFS and OS rates in the NK cell group were significantly higher than those in the control group (51.1% versus 35%, P= 0.044; 72.5% versus 51.6%, P= 0.037, respectively). Among patients with poorly differentiated carcinomas and low expression of human leukocyte antigen (HLA)-1, the median PFS in the NK cell group versus the control group was 23.5 versus 12.1 months (P= 0.0475) and 33.1 versus 18.5 months (P= 0.045), respectively. No significant adverse reactions were reported.

CONCLUSION

NK cell therapy in combination with chemotherapy in locally advanced CC prevented recurrence and prolonged survival with acceptable adverse effects, especially for poorly differentiated carcinomas.