PD-1/PD-L1 Based Combinational Cancer Therapy: Icing on the Cake

Shedding Light on the Role of Exosomal PD-L1 (ExoPD-L1) in Cancer Progression: an Update

Exosomes are the primary category of extracellular vesicles (EVs), which are lipid-bilayer vesicles with biological activity spontaneously secreted from either normal or tansformed cells. They serve a crucial role for intercellular communication and affect extracellular environment and the immune system. Tumor-derived exosomes (TEXs) enclose high levels of immunosuppressive proteins, including programmed death-ligand 1 (PD-L1). PD-L1 and its receptor PD-1 act as crucial immune checkpoint molecules, thus facilitating tumor advancement by inhibiting immune responses. PDL-1 is abundantly present on tumor cells and interacts with PD-1 on activated T cells, resulting in T cell suppression and allowing immune evasion of cancer cells. Various FDA-approved monoclonal antibodies inhibiting the PD-1/PD-L1 interaction are commonly used to treat a diverse range of tumors. Although the achieved results are significant, some individuals have a poor reaction to PD-1/PD-L1 blocking. PD-L1-enriched TEXs may mimic the impact of cell-surface PD-L1, consequently potentiating tumor resistance to PD1/PD-L1 based therapy. In light of this, a strong correlation between circulating exosomal PD-L1 levels and response rate to anti-PD-1/PD-L1 antibody treatment has been evinced. This article inspects the function of exosomal PDL-1 in developing resistance to anti-PD-1/PD-L1 therapy for opening new avenues for overcoming tumor resistance to such modalities and development of more favored combination therapy.

Macrophage-Induced Carboxypeptidase A4 Promotes the Progression of Anaplastic Thyroid Cancer

Background: The density of tumor-associated macrophages in the tumor microenvironment of anaplastic thyroid cancer (ATC) is associated with poor prognosis. However, the crosstalk between macrophages and ATC cells is poorly understood. This study aimed to examine the impact of macrophages on cancer cell phenotypes. We found a new mediator between M2 macrophages and ATC cells through proteomics analysis. Methods: The role of macrophages in proliferation, migration, and invasion of ATC cells was evaluated using coculture assay and conditioned medium (CM). Secretory factors in the CM from single or coculture were identified using liquid chromatography-tandem mass spectrometry proteomics analysis. We evaluated the role of the secretory factor in proliferation, migration, and invasion of cancer cells. In vivo xenograft model was used to evaluate the effect of the factor. Results: M2 macrophages significantly increased the proliferation, migration, and invasion of ATC cells, whereas M1 macrophages decreased the proliferation, migration, and invasion of ATC cells. Based on proteomic analysis of CM, we identify carboxypeptidase A4 (CPA4) as a mediator of the crosstalk between macrophages and ATC cells. CPA4 was only detected in the coculture media of M2 macrophage/8505C, and its expression in cancer cells increased by M2 macrophage. The expression of CPA4 protein was significantly higher in human thyroid cancers, particularly in ATCs, than normal and benign tissues. A bioinformatics analysis of public data revealed that CPA4 expression was associated with poor prognosis and dedifferentiation of thyroid cancer. Knockdown of CPA4 suppressed proliferation, colony formation, migration, and invasion of ATC cells, consistent with the decrease of STAT3, ERK, and AKT/mTOR phosphorylation and epithelial-mesenchymal transition (EMT) marker expression. In addition, the increased expression of CPA4 in cancer cells by M2 macrophage stimulation induced the polarization of macrophages to the M2 phenotype, which formed a positive feedback loop. Xenograft tumors did not develop after CPA4 knockdown. Conclusions: Our data suggest that CPA4 stimulates the progression of thyroid cancer by mediating between M2 macrophages and ATC cells. CPA4 can be a new therapeutic target for the treatment of patients with ATC.

Metabolomics at the tumor microenvironment interface: Decoding cellular conversations

Cancer heterogeneity remains a significant challenge for effective cancer treatments. Altered energetics is one of the hallmarks of cancer and influences tumor growth and drug resistance. Studies have shown that heterogeneity exists within the metabolic profile of tumors, and personalized-combination therapy with relevant metabolic interventions could improve patient response. Metabolomic studies are identifying novel biomarkers and therapeutic targets that have improved treatment response. The spatial location of elements in the tumor microenvironment are becoming increasingly important for understanding disease progression. The evolution of spatial metabolomics analysis now allows scientists to deeply understand how metabolite distribution contributes to cancer biology. Recently, these techniques have spatially resolved metabolite distribution to a subcellular level. It has been proposed that metabolite mapping could improve patient outcomes by improving precision medicine, enabling earlier diagnosis and intraoperatively identifying tumor margins. This review will discuss how altered metabolic pathways contribute to cancer progression and drug resistance and will explore the current capabilities of spatial metabolomics technologies and how these could be integrated into clinical practice to improve patient outcomes.

Sokotrasterol Sulfate Suppresses IFN-γ-Induced PD-L1 Expression by Inhibiting JAK Activity

PD-1/PD-L1 monoclonal antibodies exhibit promising therapeutic effectiveness in multiple cancers. However, developing a simple and efficient non-antibody treatment strategy using the PD-1/PD-L1 signaling pathway still remains challenging. In this study, we developed a flow cytometry assay to screen bioactive compounds with PD-L1 inhibitory activity. A total of 409 marine natural products were screened, and sokotrasterol sulfate (SKS) was found to efficiently suppress the IFN-γ-induced PD-L1 expression. SKS sensitizes the tumor cells to antigen-specific T-cell killing in the T cell-tumor cell coculture system. Mechanistically, SKS directly targeted Janus kinase (JAK) to inhibit the downstream activation of signal transducer and activator of transcription (STAT) and the subsequent transcription of PDL1. Our findings highlight the immunological role of SKS that may act as a basis for a potential immunotherapeutic agent.

The Development and Characterization of a Next-Generation Oncolytic Virus Armed with an Anti-PD-1 sdAb for Osteosarcoma Treatment In Vitro

Osteosarcoma (OS) is a primary bone malignancy characterized by an aggressive nature, limited treatment options, low survival rate, and poor patient prognosis. Conditionally replicative adenoviruses (CRAds) armed with immune checkpoint inhibitors hold great potential for enhanced therapeutic efficacy. The present study aims to investigate the anti-tumor efficacy of CAV2-AU-M2, a CAV2-based CRAd armed with an anti-PD-1 single-domain antibody (sdAb), against OS cell lines in vitro. The infection, conditional replication, cytopathic effects, and cytotoxicity of CAV2-AU-M2 were tested in four different OS cell lines in two-dimensional (2D) and three-dimensional (3D) cell cultures. CAV2-AU-M2 showed selective replication in the OS cells and induced efficient tumor cell lysis and death. Moreover, CAV2-AU-M2 produced an anti-PD-1 sdAb that demonstrated effective binding to the PD-1 receptors. This study demonstrated the first CRAd armed with an anti-PD-1 sdAb. This combined approach of two distinct immunotherapies is intended to enhance the anti-tumor immune response in the tumor microenvironment.

A Review of Ultrasound-Mediated Checkpoint Inhibitor Immunotherapy

Over the past decade, immunotherapy has emerged as a major modality in cancer medicine. However, despite its unprecedented success, immunotherapy currently benefits only a subgroup of patients, may induce responses of limited duration and is associated with potentially treatment-limiting side effects. In addition, responses to immunotherapeutics are sometimes diminished by the emergence of a complex array of resistance mechanisms. The efficacy of immunotherapy depends on dynamic interactions between tumour cells and the immune landscape in the tumour microenvironment. Ultrasound, especially in conjunction with cavitation-promoting agents such as microbubbles, can assist in the uptake and/or local release of immunotherapeutic agents at specific target sites, thereby increasing treatment efficacy and reducing systemic toxicity. There is also increasing evidence that ultrasound and/or cavitation may themselves directly stimulate a beneficial immune response. In this review, we summarize the latest developments in the use of ultrasound and cavitation agents to promote checkpoint inhibitor immunotherapy.

A first-in-human, open-label, dose-escalation and dose-expansion phase I study to evaluate the safety, tolerability, pharmacokinetics/pharmacodynamics, and antitumor activity of QL1604, a humanized anti-PD-1 mAb, in patients with advanced or metastatic solid tumors

Background

QL1604 is a humanized immunoglobulin G4 monoclonal antibody against programmed cell death protein 1. This first-in-human, open-label phase I study aimed to investigate the safety and tolerability and to identify the recommended doses of QL1604 for future studies. Pharmacokinetics/pharmacodynamics (PK/PD) and preliminary antitumor activity were also assessed.

Methods

Patients with advanced or metastatic solid tumors who failed or had no standard therapies available were recruited. In the dose-escalation phase, patients were treated with QL1604 at 0.3 mg/kg, 1 mg/kg, 3 mg/kg, and 10 mg/kg intravenously once every 2 weeks (Q2W) in an accelerated titration with a traditional 3 + 3 design, followed by a dose-expansion phase at 3 mg/kg Q2W, 3 mg/kg once every 3 weeks (Q3W), 10 mg/kg Q2W and a fixed dose of 200 mg Q3W. Dose-limiting toxicities (DLTs) were assessed during the first 28 days after the first dose of study drug. Adverse events (AEs) were graded per National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0, and antitumor activity of QL1604 was evaluated by investigators on the basis of Response Evaluation Criteria in Solid Tumors version 1.1.

Results

A total of 35 patients with advanced or metastatic solid tumors were enrolled. DLTs were reported in one patient at the dose level of 3 mg/kg Q2W (grade 3 immune-mediated myositis and myasthenia gravis), and maximum tolerated dose was not reached. The most frequent treatment-related AEs (≥10%) were fatigue (37.1%), anemia (22.9%), increased blood thyroid-stimulating hormone (17.1%), increased aspartate aminotransferase (AST) (17.1%), increased alanine aminotransferase (ALT) (14.3%), decreased white blood cell (WBC) count (11.4%), rash (14.3%), and pruritus (14.3%). AEs leading to discontinuation of QL1604 occurred in three of the 35 patients (8.6%). Partial responses (PRs) occurred in seven patients, resulting in an objective response rate of 20.0% (7/35). Single dose of QL1604 exhibited a dose-dependent increase in the exposure ranging from 0.3 mg/kg to 10 mg/kg. Mean receptor occupancy (RO) for QL1604 at the dose of 3 mg/kg (Q2W and Q3W) and 200 mg (Q3W) was greater than 80% during cycle 1 after one infusion.

Conclusion

QL1604 monotherapy exhibited favorable safety, PK, and signal of antitumor activity in patients with advanced or metastatic solid tumors, and the results supported further clinical studies of QL1604. On the basis of the safety, PK, and RO data, the recommended dosage for further clinical trials is 3 mg/kg or a fixed dose of 200 mg given every 3 weeks.

Clinical Trial Registration

https://classic.clinicaltrials.gov/ct2/show/NCT05649761?term=QL1604&draw=2&rank=1, identifier NCT05649761.

A CD276-Targeted Antibody-Drug Conjugate to Treat Non-Small Lung Cancer (NSCLC)

Non-small cell lung cancer (NSCLC) patients, accounting for approximately 85% of lung cancer cases, are usually diagnosed in advanced stages. Traditional surgical resection and radiotherapy have very limited clinical benefits. The objective of this study was to develop and evaluate a targeted therapy, antibody-drug conjugate (ADC), for NSCLC treatment. Specifically, the CD276 receptor was evaluated and confirmed as an ideal surface target of NSCLC in the immunohistochemistry (IHC) staining of seventy-three patient tumor microarrays and western blotting analysis of eight cell lines. Our anti-CD276 monoclonal antibody (mAb) with cross-activity to both human and mouse receptors showed high surface binding, effective drug delivery and tumor-specific targeting in flow cytometry, confocal microscopy, and in vivo imaging system analysis. The ADC constructed with our CD276 mAb and payload monomethyl auristatin F (MMAF) showed high anti-NSCLC cytotoxicity to multiple lines and effective anti-tumor efficacy in both immunocompromised and immunocompetent NSCLC xenograft mouse models. The brief mechanism study revealed the integration of cell proliferation inhibition and immune cell reactivation in tumor microenvironments. The toxicity study did not detect off-target immune toxicity or peripheral toxicity. Altogether, this study suggested that anti-CD276 ADC could be a promising candidate for NSCLC treatment.

Molecular Farming of Pembrolizumab and Nivolumab

Immune checkpoint inhibitors (ICIs) are a class of immunotherapy agents capable of alleviating the immunosuppressive effects exerted by tumorigenic cells. The programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) immune checkpoint is one of the most ubiquitous checkpoints utilized by tumorigenic cells for immune evasion by inducing apoptosis and inhibiting the proliferation and cytokine production of T lymphocytes. Currently, the most frequently used ICIs targeting the PD-1/PD-L1 checkpoint include monoclonal antibodies (mAbs) pembrolizumab and nivolumab that bind to PD-1 on T lymphocytes and inhibit interaction with PD-L1 on tumorigenic cells. However, pembrolizumab and nivolumab are costly, and thus their accessibility is limited in low- and middle-income countries (LMICs). Therefore, it is essential to develop novel biomanufacturing platforms capable of reducing the cost of these two therapies. Molecular farming is one such platform utilizing plants for mAb production, and it has been demonstrated to be a rapid, low-cost, and scalable platform that can be potentially implemented in LMICs to diminish the exorbitant prices, ultimately leading to a significant reduction in cancer-related mortalities within these countries.

Light-initiated aggregation of gold nanoparticles for synergistic chemo-photothermal tumor therapy

The combination of chemotherapy with photothermal therapy (PTT) has attracted extensive attention due to its excellent synergetic effect attributing to the fact that hyperthermia can effectively promote the tumor uptake of chemotherapeutic drugs. Herein, we propose a light-initiated gold nanoparticle (AuNP) aggregation boosting the uptake of chemotherapeutic drugs for enhanced chemo-photothermal tumor therapy. Novel light-responsive AuNPs (tm-AuNPs) were rationally designed and fabricated by conjugating both 2,5-diphenyltetrazole (Tz) and methacrylic acid (Ma) onto the surface of AuNPs with small size (∼20 nm). Upon the irradiation of 405 nm laser, AuNPs could be initiated to form aggregates specifically within tumors through the covalent cycloaddition reaction between Tz and Ma. Taking advantage of the controllable photothermal effect of Au aggregates under NIR excitation, improved enrichment of doxorubicin (DOX) in tumor tissues was realized, combined with PTT, resulting in outstanding synergetic anti-tumor efficacy in living mice. We thus believe that this light-initiated AuNP aggregation approach would offer a valuable and powerful tool for precisely synergistic chemo-photothermal tumor therapy.

Defining the Emergence of New Immunotherapy Approaches in Breast Cancer: Role of Myeloid-Derived Suppressor Cells

Breast cancer (BC) continues to be the most diagnosed tumor in women and a very heterogeneous disease both inter- and intratumoral, mainly given by the variety of molecular profiles with different biological and clinical characteristics. Despite the advancements in early detection and therapeutic strategies, the survival rate is low in patients who develop metastatic disease. Therefore, it is mandatory to explore new approaches to achieve better responses. In this regard, immunotherapy arose as a promising alternative to conventional treatments due to its ability to modulate the immune system, which may play a dual role in this disease since the relationship between the immune system and BC cells depends on several factors: the tumor histology and size, as well as the involvement of lymph nodes, immune cells, and molecules that are part of the tumor microenvironment. Particularly, myeloid-derived suppressor cell (MDSC) expansion is one of the major immunosuppressive mechanisms used by breast tumors since it has been associated with worse clinical stage, metastatic burden, and poor efficacy of immunotherapies. This review focuses on the new immunotherapies in BC in the last five years. Additionally, the role of MDSC as a therapeutic target in breast cancer will be described.

Chelerythrine, a novel small molecule targeting IL-2, inhibits melanoma progression by blocking the interaction between IL-2 and its receptor

AIMS

In this study, we investigated the inhibition of IL-2 activity and anticancer efficacy of chelerythrine (CHE), a natural small molecule that targets IL-2 and inhibits CD25 binding, and elucidated the mechanism underlying the action of CHE on immune cells.

MAIN METHODS

CHE was discovered by competitive binding ELISA and SPR analysis. The effect of CHE on IL-2 activity was evaluated in CTLL-2, HEK-Blue reporter and immune cells, and in ex vivo generation of regulatory T cells (Treg cells). The antitumor activity of CHE was evaluated in B16F10 tumor-bearing C57BL/6 or BALB/c nude mice.

KEY FINDINGS

We identified that CHE, which acts as an IL-2 inhibitor, selectively inhibits the interaction between IL-2 and IL-2Rα and directly binds to IL-2. CHE inhibited the proliferation and signaling of CTLL-2 cells and suppressed IL-2 activity in HEK-Blue reporter and immune cells. CHE prevented the conversion of naive CD4⁺ T cells into CD4⁺CD25⁺Foxp3⁺ Treg cells in response to IL-2. CHE reduced tumor growth in C57BL/6 mice but not in T-cell-deficient mice, upregulated the expression of IFN-γ and cytotoxic molecules, and limited Foxp3 expression. Furthermore, the combination of CHE and a PD-1 inhibitor synergistically increased antitumor activity in melanoma-bearing mice and almost completely regressed the implanted tumors.

SIGNIFICANCE

We found that CHE, which targets IL-2 and inhibits its binding to CD25, exhibits T cell-mediated antitumor activity and that combination therapy with CHE and PD-1 inhibitor induced synergistic antitumor effects, suggesting that CHE may be a promising anticancer agent for melanoma monotherapy and combination therapy.

PD-L1 small-molecule modulators: A new hope in epigenetic-based multidrug cancer therapy?

Programmed death-ligand 1 (PD-L1) is an immune checkpoint protein the overexpression of which results in an inhibitory signal that induces T cell exhaustion responsible for immune escape in tumors. Immunotherapy strategies targeting the PD-L1 pathway have achieved remarkable success in treating various types of cancer. More recently, numerous advances in understanding the complex PD-L1 biology have been made, and the first small-molecule inhibitors have been described in the literature. In this review, we highlight the most promising recent advances in understanding the complex regulation mechanisms focusing on small-molecule modulators, which could be used in rational therapy combinations with other epigenetic chemotherapeutic agents.

DSP-0509, a systemically available TLR7 agonist, exhibits combination effect with immune checkpoint blockade by activating anti-tumor immune effects

TLR7 is an innate immune receptor that recognizes single-stranded RNAs, and its activation leads to anti-tumor immune effects. Although it is the only approved TLR7 agonist in cancer therapy, imiquimod is allowed to be administered with topical formulation. Thus, systemic administrative TLR7 agonist is expected in terms of expanding applicable cancer types. Here, we demonstrated the identification and characterization of DSP-0509 as a novel small-molecule TLR7 agonist. DSP-0509 is designed to have unique physicochemical features that could be administered systemically with a short half-life. DSP-0509 activated bone marrow-derived dendritic cells (BMDCs) and induced inflammatory cytokines including type I interferons. In the LM8 tumor-bearing mouse model, DSP-0509 reduced tumor growth not only in subcutaneous primary lesions but also in lung metastatic lesions. DSP-0509 inhibited tumor growth in several syngeneic tumor-bearing mouse models. We found that the CD8⁺ T cell infiltration of tumor before treatment tended to be positively correlated with anti-tumor efficacy in several mouse tumor models. The combination of DSP-0509 with anti-PD-1 antibody significantly enhanced the tumor growth inhibition compared to each monotherapy in CT26 model mice. In addition, the effector memory T cells were expanded in both the peripheral blood and tumor, and rejection of tumor re-challenge occurred in the combination group. Moreover, synergistic anti-tumor efficacy and effector memory T cell upregulation were also observed for the combination with anti-CTLA-4 antibody. The analysis of the tumor-immune microenvironment by using the nCounter assay revealed that the combination of DSP-0509 with anti-PD-1 antibody enhanced infiltration by multiple immune cells including cytotoxic T cells. In addition, the T cell function pathway and antigen presentation pathway were activated in the combination group. We confirmed that DSP-0509 enhanced the anti-tumor immune effects of anti-PD-1 antibody by inducing type I interferons via activation of dendritic cells and even CTLs. In conclusion, we expect that DSP-0509, a new TLR7 agonist that synergistically induces anti-tumor effector memory T cells with immune checkpoint blockers (ICBs) and can be administered systemically, will be used in the treatment of multiple cancers.

Efficacy and safety of serplulimab plus nab-paclitaxel in previously treated patients with PD-L1-positive advanced cervical cancer: a phase II, single-arm study

Objective

We report the efficacy and safety of serplulimab, a novel humanized anti-programmed death-1 antibody, plus nanoparticle albumin-bound (nab)-paclitaxel in previously treated patients with programmed death ligand-1 (PD-L1)-positive advanced cervical cancer.

Methods

Patients diagnosed with PD-L1-positive (combined positive score ≥1) cervical cancer were enrolled in this single-arm, open-label, phase II study. They were given serplulimab 4.5 mg/kg for up to 2 years (35 dosing cycles) plus nab-paclitaxel 260 mg/m² for up to six cycles once every 3 weeks. Primary endpoints were safety and objective response rate (ORR) assessed by independent radiological review committee (IRRC) per RECIST version 1.1. Secondary endpoints included ORR assessed by the investigator, duration of response (DOR), progression-free survival (PFS), and overall survival (OS).

Results

Between December 2019 and June 2020, 52 patients were screened and 21 were enrolled. IRRC-assessed ORR was 57.1% (95% confidence interval [CI] 34.0-78.2%); 3 (14.3%) patients achieved complete response and 9 (42.9%) partial response. The median DOR was not reached (NR) (95% CI 4.1-NR). IRRC-assessed median PFS was 5.7 months (95% CI 3.0-NR), and median OS was 15.5 months (95% CI 10.5-NR). Investigator-assessed ORR was 47.6% (95% CI 25.7-70.2%). Seventeen (81.0%) patients experienced grade ≥3 treatment-emergent adverse events. Grade ≥3 adverse drug reactions were reported in 7 (33.3%) patients. Immune-related adverse events occurred in 12 (57.1%) patients.

Conclusions

In previously treated patients with PD-L1-positive advanced cervical cancer, serplulimab plus nab-paclitaxel provided durable clinical activity and a manageable safety profile.

Clinical trial registration

ClinicalTrials.gov, identifier NCT04150575.

Leveraging the replication stress response to optimize cancer therapy

High-fidelity DNA replication is critical for the faithful transmission of genetic information to daughter cells. Following genotoxic stress, specialized DNA damage tolerance pathways are activated to ensure replication fork progression. These pathways include translesion DNA synthesis, template switching and repriming. In this Review, we describe how DNA damage tolerance pathways impact genome stability, their connection with tumorigenesis and their effects on cancer therapy response. We discuss recent findings that single-strand DNA gap accumulation impacts chemoresponse and explore a growing body of evidence that suggests that different DNA damage tolerance factors, including translesion synthesis polymerases, template switching proteins and enzymes affecting single-stranded DNA gaps, represent useful cancer targets. We further outline how the consequences of DNA damage tolerance mechanisms could inform the discovery of new biomarkers to refine cancer therapies.

ABC transporters affects tumor immune microenvironment to regulate cancer immunotherapy and multidrug resistance

Multidrug resistance (MDR) is the phenomenon in which cancer cells simultaneously develop resistance to a broad spectrum of structurally and mechanistically unrelated drugs. MDR severely hinders the effective treatment of cancer and is the major cause of chemotherapy failure. ATP-binding cassette (ABC) transporters are extensively expressed in various body tissues, and actively transport endogenous and exogenous substrates through biological membranes. Overexpression of ABC transporters is frequently observed in MDR cancer cells, which promotes efflux of chemotherapeutic drugs and reduces their intracellular accumulation. Increasing evidence suggests that ABC transporters regulate tumor immune microenvironment (TIME) by transporting various cytokines, thus controlling anti-tumor immunity and sensitivity to anticancer drugs. On the other hand, the expression of various ABC transporters is regulated by cytokines and other immune signaling molecules. Targeted inhibition of ABC transporter expression or function can enhance the efficacy of immune checkpoint inhibitors by promoting anticancer immune microenvironment. This review provides an update on the recent research progress in this field.

Role of chemokines in HPV-induced cancers

Human papillomaviruses (HPVs) cause cancers of the uterine cervix, oropharynx, anus, and vulvovaginal tract. Low-risk HPVs, such as HPV6 and 11, can also cause benign mucosal lesions including genital warts, and in patients with recurrent respiratory papillomatosis, lesions in the larynx, and on occasion, in the lungs. However, both high and less tumorigenic HPVs share a striking commonality in manipulating both innate and adaptive immune responses in HPV- infected keratinocytes, the natural host for HPV infection. In addition, immune/inflammatory cell infiltration into the tumor microenvironment influences cancer growth and prognosis, and this process is tightly regulated by different chemokines. Chemokines are small proteins and exert their biological effects by binding with G protein-coupled chemokine receptors (GPCRs) that are found on the surfaces of select target cells. Chemokines are not only involved in the establishment of a pro-tumorigenic microenvironment and organ-directed metastases but also involved in disease progression through enhancing tumor cell growth and proliferation. Therefore, having a solid grasp on chemokines and immune checkpoint modulators can help in the treatment of these cancers. In this review, we discuss the recent advances on the expression patterns and regulation of the main chemokines found in HPV-induced cancers, and their effects on both immune and non-immune cells in these lesions. Importantly, we also present the current knowledge of therapeutic interventions on the expression of specific chemokine and their receptors that have been shown to influence the development and progression of HPV-induced cancers.

Tumor-intrinsic SIRPA promotes sensitivity to checkpoint inhibition immunotherapy in melanoma

Checkpoint inhibition immunotherapy has revolutionized cancer treatment, but many patients show resistance. Here we perform integrative transcriptomic and proteomic analyses on emerging immuno-oncology targets across multiple clinical cohorts of melanoma under anti-PD-1 treatment, on both bulk and single-cell levels. We reveal a surprising role of tumor-intrinsic SIRPA in enhancing antitumor immunity, in contrast to its well-established role as a major inhibitory immune modulator in macrophages. The loss of SIRPA expression is a marker of melanoma dedifferentiation, a key phenotype linked to immunotherapy efficacy. Inhibition of SIRPA in melanoma cells abrogates tumor killing by activated CD8+ T cells in a co-culture system. Mice bearing SIRPA-deficient melanoma tumors show no response to anti-PD-L1 treatment, whereas melanoma-specific SIRPA overexpression significantly enhances immunotherapy response. Mechanistically, SIRPA is regulated by its pseudogene, SIRPAP1. Our results suggest a complicated role of SIRPA in the tumor ecosystem, highlighting cell-type-dependent antagonistic effects of the same target on immunotherapy.

Highly efficient hybridoma generation and screening strategy for anti-PD-1 monoclonal antibody development

Programmed cell death protein 1 (PD-1) plays a significant role in suppressing antitumor immune responses. Cancer treatment with immune checkpoint inhibitors (ICIs) targeting PD-1 has been approved to treat numerous cancers and is the backbone of cancer immunotherapy. Anti-PD-1 molecule is necessary for next-generation cancer immunotherapy to further improve clinical efficacy and safety as well as integrate into novel treatment combinations or platforms. We developed a highly efficient hybridoma generation and screening strategy to generate high-potency chimeric anti-PD-1 molecules. Using this strategy, we successfully generated several mouse hybridoma and mouse/human chimeric clones that produced high-affinity antibodies against human PD-1 with high-quality in vitro PD-1/PD-L1 binding blockade and T cell activation activities. The lead chimeric prototypes exhibited overall in vitro performance comparable to commercially available anti-PD-1 antibodies and could be qualified as promising therapeutic candidates for further development toward immuno-oncology applications.

Investigation of the therapeutic potential of recombinant bispecific bivalent anti-PD-L1/VEGF nanobody in inhibition of angiogenesis

Immunotherapy's using monoclonal antibodies targeting programmed death ligand-1 (PD-L1) on cancer cells as a biomarker of escape from response to immune checkpoint has demonstrated efficacy in treating many solid tumors. In addition, some of the signals, such as vascular endothelial growth factor (VEGF), bind to receptors on the surface of normal endothelial cells and encourage angiogenesis, or the formation and survival of new blood vessels. Due to the special features of nanobodies with high specificity and affinity as a powerful new tool in cancer therapy, here, a recombinant bispecific bivalent anti-PD-L1/VEGF nanobody was constructed and its functionality in inhibition of angiogenesis in vitro was investigated. Results demonstrated that bivalent anti-PD-L1/VEGF nanobody efficiently inhibited HUVEC and A431 cells proliferation and tube formation. In addition, bivalent anti-PD-L1/VEGF nanobody efficiently inhibited angiogenesis in an ex ovo Chick Chorioallantoic Membrane assay. The results indicate for the potential of bivalent anti-PD-L1/VEGF nanobody as a novel promising tool for cancer therapy.

Clinical applications of liquid biopsy in HPV‐negative and HPV‐positive head and neck squamous cell carcinoma: advances and challenges

Head and neck squamous cell carcinomas (HNSCCs) represent the most common epithelial tumors that arise from mucosa of the oral cavity, pharynx, and larynx. The development of HNSCCs is usually associated with tobacco use, alcohol consumption, and human papillomavirus (HPV) infection. Most HNSCCs are diagnosed in advanced states, leading to a worse clinical outcome. Screening tests based on potential biomarkers associated with HNSCCs could improve this scenario. Liquid biopsy has emerged as a promising area of cancer investigation, offering a minimally invasive approach to track circulating biomarkers in body fluids that could potentially contribute to the diagnosis, predict prognosis, and monitor response to treatment. This review will discuss translational studies describing the clinical applications of liquid biopsy in HPV-negative and HPV-positive HNSCCs focused on circulating nucleic acids [cell-free DNA (cfDNA) and cell-free RNA (cfRNA)], circulating tumor cells (CTCs), and extracellular vesicles (EVs), which can be found in plasma, serum, and saliva.

Multisite Radiotherapy Combined With Tislelizumab for Metastatic Castration-Resistant Prostate Cancer With Second-Line and Above Therapy Failure: Study Protocol for an Open-Label, Single-Arm, Phase Ib/II Study

Background

Tislelizumab combined with radiotherapy as a salvage treatment for patients with end-stage metastatic castration-resistant prostate cancer (mCRPC) is not reported. This study aimed to describe a protocol to evaluate the safety and efficacy of multisite radiotherapy combined with tislelizumab as a salvage therapy for mCRPC in patients who had at least one second-line treatment failure.

Methods

The study included patients with mCRPC who had at least one lesion suitable for radiotherapy and failed androgen deprivation therapy (ADT), followed by at least one novel second-line endocrine therapy. All patients received tislelizumab monotherapy induction therapy for two cycles, then combined with multisite radiotherapy for one cycle, followed by tislelizumab maintenance therapy, until either disease progressed or the patient developed unacceptable toxicity. Radiation methods and lesions were individually selected according to the specified protocol. Primary endpoints included safety and objective response rate. Secondary endpoints included prostate-specific antigen (PSA) response rate, disease control rate, overall survival, radiographic progression-free survival (rPFS), and biochemical progression-free survival (bPFS). Furthermore, the exploratory endpoints included the identification of the predictive biomarkers and exploration of the correlation between biomarkers and the tumor response to the combined regimen.

Discussion

This study included three treatment stages to evaluate the efficacy of immunotherapy and the combination of immunotherapy and radiotherapy for patients with mCRPC who have had at least second-line treatment failure. Additionally, radiation-related and immune-related early and late toxicities were determined, respectively. Furthermore, the study also aimed to identify the predictive biomarkers associated with immunotherapy for treating mCRPC.

Trial Registration

https://www.chictr.org.cn/showproj.aspx?proj=126359, identifier ChiCTR2100046212.

Atlas of PD-L1 for Pathologists: Indications, Scores, Diagnostic Platforms and Reporting Systems

Background. Innovative drugs targeting the PD1/PD-L1 axis have opened promising scenarios in modern cancer therapy. Plenty of assays and scoring systems have been developed for the evaluation of PD-L1 immunohistochemical expression, so far considered the most reliable therapeutic predictive marker. Methods. By gathering the opinion of acknowledged experts in dedicated fields of pathology, we sought to update the currently available evidence on PD-L1 assessment in various types of tumors. Results. Robust data were progressively collected for several anatomic districts and leading international agencies to approve specific protocols: among these, TPS with 22C3, SP142 and SP263 clones in lung cancer; IC with SP142 antibody in breast, lung and urothelial tumors; and CPS with 22C3/SP263 assays in head and neck and urothelial carcinomas. On the other hand, for other malignancies, such as gastroenteric neoplasms, immunotherapy has been only recently introduced, often for particular histotypes, so specific guidelines are still lacking. Conclusions. PD-L1 immunohistochemical scoring is currently the basis for allowing many cancer patients to receive properly targeted therapies. While protocols supported by proven data are already available for many tumors, dedicated studies and clinical trials focusing on harmonization of the topic in other still only partially explored fields are surely yet advisable.

Rational design of synthetically tractable HDAC6/HSP90 dual inhibitors to destroy immune-suppressive tumor microenvironment

INTRODUCTION

The tumor microenvironment is mainly flooded with immunosuppressive cells and inhibitory cytokines, resulting in the inability of effective immune cells to infiltrate and recognize tumors and even the loss of anti-cancer ability.

OBJECTIVES

We propose a novel HDAC6/HSP90 dual inhibitory strategy as well as a chemoimmunotherapeutic agent that does not only kill tumor cells but also destroys the tumor microenvironment and enhances anti-cancer immunity.

METHODS

A hybrid scaffold construction approach was leveraged to furnish a series of rationally designed resorcinol-based hydroxamates as dual selective HDAC6/HSP90 inhibitors. The drug design campaign commenced with a fragment recruitment process to pinpoint validated structural units to inhibit HDAC6 and HSP90, followed by their installation in flexible HDAC inhibitory templates via an efficient and facile multistep synthetic route. Subsequent evaluations identified a strikingly potent selective HDAC6/HSP90 dual inhibitor (compound 17) via molecular and biological analysis in vitro and in vivo.

RESULTS

Compound 17 exhibited not only direct cytotoxicity to cancer cells but also downregulated immune checkpoints (PD-L1 and IDO) expression in tumors via the inhibition of STAT1 pathway and degradation of oncogene proteins (Src, AKT, Rb, and FAK), leading to in vivo tumor growth inhibition. These multiple effects enabled the effector T cells to largely infiltrate into the tumor region and release granzyme B to kill cancer cells. In addition, compound 17 also decreased TGF-β secretion from normal cells, resulting in the systemic reduction of immunosuppressive regulatory T cells. Delightfully, a cocktail treatment of compound 17 and anti-PD-1 antibodies demonstrated synergistic efficacy to eliminate solid tumors with 83.9% of tumor growth inhibition.

CONCLUSION

In summary, the impressive activity profile of compound 17, as an effective anticancer agent and a potential immunosensitizer, forecasts the application of HDAC6/HSP90 dual inhibitory strategy to overcome the immunosuppressive tumor microenvironment.

Immunotherapy in Advanced Non-Small Cell Lung Cancers: Current Status and Updates

Non-small-cell lung cancer (NSCLC) is a major health burden, and novel therapeutic options are needed to help solve this problem. One such option is immunotherapy, which targets immune checkpoint molecules that inhibit cancer cells, decreasing immune system activation, for example, immunotherapies target PD-1, its ligand PD-L1, and CTLA-4. There have been major advances in the development of agents that inhibit these molecules, called immune checkpoint inhibitors, and several of them are already approved for usage in NSCLC patients, especially in advanced stages. In this review, the reasons why immune checkpoint inhibitors could be beneficial and the clinical results of studies using these drugs for advanced or recurrent NSCLC patients are discussed, as is the safety profile of the drugs.

Construction of ovarian metastasis-related immune signature predicting prognosis of gastric cancer patients

BACKGROUND

Ovarian metastasis (OM) results in poor survival of gastric cancer (GC) patients. While immunotherapy has emerged as a promising approach for late-stage GC, validated immune-related prognostic signatures still remain in need. In this study, we constructed an ovarian metastasis- and immune-related prognostic signature (OMIRPS), characterized the molecular and immune features of OMIRPS-categorized subgroups and predicted their potential response to immunotherapy.

METHODS

Three individual cohorts were used to construct and evaluate OMIRPS: RNA-seq of matched primary GC and OM from Fudan University Shanghai Cancer Center (FUSCC) (discovery cohort, n = 4), The Cancer Genome Atlas (TCGA) (training cohort, n = 544) and GSE84437 (validation cohort, n = 433). Differentially expressed genes (DEGs) identified between primary GC and OM and immune-related genes (IRGs) from the ImmPort and InnateDB databases were used to identify immune-related prognostic hub genes, which were further used to construct OMIRPS by using LASSO regression analysis. Prognosis, molecular characteristics, immune features, and differential immunotherapy efficacy between different OMIRPS subgroups were analyzed.

RESULTS

Functional analyses of DEGs revealed the significance of immune-related signatures and pathways in the OM. Immune-related prognostic hub genes including TNFRSF18, CARD11, BCL11B, NRP1, BNIP3L, and ATF3 were utilized to construct OMIRPS, which was identified as an independent prognostic factor. Comprehensive analyses unveiled the distinctive molecular and immune characteristics of OMIRPS-high and -low subgroup in regard to enriched pathways, mutation rate, tumor mutation burden, microsatellite instability status, infiltrated immune cell, immune exclusion score, and the prediction of immunotherapy efficacy. Additionally, OMIRPS was associated with Immune Subtypes with borderline significance.

CONCLUSIONS

RNA-seq of paired primary and ovarian metastatic tumors unveiled the significance of immune-related pathways and tumor immune microenvironment in OM. OMIRPS served as a promising biomarker to predict the prognosis of GC patients and distinguish the molecular features, immune characteristics, and efficacy of immunotherapy between different subgroups.

Development and validation of a high performance liquid chromatography-MS/MS method for determination of SOMCL-15-290 in a first-in-human study

Background: SOMCL-15-290 is a novel inhibitor that targets FGF receptor, CSF1 receptor and VEGF receptor (kinase insert domain receptor). Aim: This study was aiming at developing a specific high performance liquid chromatography-MS/MS method for quantifying SOMCL-15-290 in human plasma and supporting the first-in-human study. Methods: Plasma samples were prepared using the protein precipitation method and separated on a C18 110A column with acetonitrile and 0.2% formic acid solution as mobile phases. Quantification of SOMCL-15-290 was operated on an Xevo-TQS triple quadrupole tandem mass spectrometer in electrospray ionization positive mode. Results & conclusion: The validated determination method of SOMCL-15-290 has proved feasible and was successfully utilized in the first-in-human study of SOMCL-15-290 in advanced solid tumor patients.

CircPCBP2 promotes the stemness and chemoresistance of DLBCL via targeting miR-33a/b to disinhibit PD-L1

Diffuse large B‐cell lymphoma (DLBCL) is the most common lymphoid malignancy with a high relapse rate of up to 40%. The prognosis of the disease needs improvement and requires a understanding of its molecular mechanism. We investigated the mechanisms of DLBCL development and its sensitivity to chemotherapy by focusing on circPCBP2/miR‐33a/b/PD‐L1 axis. Human DLBCL specimens and cultured cancer cell lines were used. Features of circPCBP2 were systematically characterized through Sanger sequencing, Actinomycin D, RNase R treatment, and FISH. The expression levels of circPCBP2, miR‐33a/b, PD‐L1, stemness‐related markers, ERK/AKT and JAK2/STAT3 signaling were measured using qRT‐PCR, western blotting, and immunohistochemistry. Stemness of DLBCL cells was assessed through spheroid formation assay and flow cytometry. Cell viability and apoptosis upon cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) treatment were determined using MTT assay and flow cytometry, respectively. Interactions of circPCBP2‐miR‐33a/b and miR‐33a/b‐PD‐L1 were validated using dual luciferase activity assay and RNA‐RIP. Nude mouse xenograft model was used to assess the function of circPCBP2 in DLBCL growth in vivo. circPCBP2 was upregulated in human DLBCL specimens and cultured DLBCL cells while miR‐33a/b was reduced. Knockdown of circPCBP2 or miR‐33a/b overexpression inhibited the stemness of DLBCL cells and promoted cancer cell apoptosis upon CHOP treatment. circPCBP2 directly bound with miR‐33a/b while miR‐33a/b targeted PD‐L1 3’‐UTR. circPCBP2 disinhibited PD‐L1 signaling via sponging miR‐33a/b. miR‐33a/b inhibitor and activating PD‐L1 reversed the effects of circPCBP2 knockdown and miR‐33a/b mimics, respectively. circPBCP2 knockdown restrained DLBCL growth in vivo and potentiated the anti‐tumor effects of CHOP. In conclusion, circPCBP2 enhances DLBCL cell stemness but suppresses its sensitivity to CHOP via sponging miR‐33a/b to disinhibit PD‐L1 expression. circPCBP2/miR‐33a/b/PD‐L1 axis could serve as a diagnosis marker or therapeutic target for DLBCL.

The cure from within? a review of the microbiome and diet in melanoma

Therapy for cutaneous melanoma, the deadliest of the skin cancers, is inextricably linked to the immune system. Once thought impossible, cures for metastatic melanoma with immune checkpoint inhibitors have been developed within the last decade and now occur regularly in the clinic. Unfortunately, half of tumors do not respond to checkpoint inhibitors and efforts to further exploit the immune system are needed. Tantalizing associations with immune health and gut microbiome composition suggest we can improve the success rate of immunotherapy. The gut contains over half of the immune cells in our bodies and increasingly, evidence is linking the immune system within our gut to melanoma development and treatment. In this review, we discuss the importance the skin and gut microbiome may play in the development of melanoma. We examine the differences in the microbial populations which inhabit the gut of those who develop melanoma and subsequently respond to immunotherapeutics. We discuss the role of dietary intake on the development and treatment of melanoma. And finally, we review the landscape of published and registered clinical trials therapeutically targeting the microbiome in melanoma through dietary supplements, fecal microbiota transplant, and microbial supplementation.

Gut Microbiota: A Promising Milestone in Enhancing the Efficacy of PD1/PD-L1 Blockade Therapy

In the past few decades, immunotherapy has emerged as one of the most promising strategies among current treatments of cancer. In particular, the field of PD1/PD-L1 inhibitors has been boosted, widely applied into clinical practice with potent therapeutic efficacy and remarkable survival benefits on various cancers such as melanoma, non-small cell lung cancer (NSCLC), and urothelial carcinoma (UC). However, the application of PD1/PD-L1 blockade therapy is still quite restricted because of unexpected toxicities, limited response rate, as well as associated resistance. In consequence, searching for potential strategies that possibly resolve the existing limitations and enhance the therapeutic responsiveness of PD1/PD-L1 blockade is of great significance. Fortunately, the gut microbiome has been demonstrated to serve as a pivotal regulator in anti-PD1/PD-L1 therapy, providing an applicable tool to improve anti-PD1/PD-L1 clinical efficacy. In this review, we summarized published advancements about how microbiota modulated in anti-PD1/PD-L1 therapy and illustrated its underlying mechanisms, giving insights into putative manipulation of gut microbiota to facilitate PD1/PD-L1 blockade.

CIMT 2021: report on the 18th Annual Meeting of the Association for Cancer Immunotherapy

After one year of absence, the 18th Annual Meeting of the Association for Cancer Immunotherapy (CIMT), Europe’s cancer immunotherapy meeting, took place virtually from 10 to 12 May 2021. Over 850 academic and clinical professionals from 30 countries met to discuss the recent advancements in cancer immunotherapy and the current progress in COVID19-related research. This meeting report summarizes the highlights of CIMT2021.

Immunotherapy for Biliary Tract Cancer in the Era of Precision Medicine: Current Knowledge and Future Perspectives

Biliary tract cancers (BTC) represent a heterogeneous and aggressive group of tumors with dismal prognosis. For a long time, BTC has been considered an orphan disease with very limited therapeutic options. In recent years a better understanding of the complex molecular landscape of biology is rapidly changing the therapeutic armamentarium. However, while 40-50% of patients there are molecular drivers susceptible to target therapy, for the remaining population new therapeutic options represent an unsatisfied clinical need. The role of immunotherapy in the continuum of treatment of patients with BTC is still debated. Despite initial signs of antitumor-activity, single-agent immune checkpoint inhibitors (ICIs) demonstrated limited efficacy in an unselected population. Therefore, identifying the best partner to combine ICIs and predictive biomarkers represents a key challenge to optimize the efficacy of immunotherapy. This review provides a critical analysis of completed trials, with an eye on future perspectives and possible biomarkers of response.

Expression of PD‑L1 and CD4+ tumor‑infiltrating lymphocytes predict survival in head and neck squamous cell carcinoma

The clinical efficacy of immune checkpoint blockade has been recently demonstrated in a variety of cancer types. The aim of the present study was to characterize the expression profile of tumor-infiltrating lymphocytes (TILs) and programmed death-ligand 1 (PD-L1) in head and neck squamous carcinoma (HNSCC). A total of 63 patients with HNSCC were enrolled in the present study. CD3⁺ and CD4⁺ TILs and the expression of PD-L1 were detected by immunohistochemistry. PD-L1 mRNA levels were evaluated by reverse transcription-quantitative PCR analysis. The association of TILs and PD-L1 with patient clinicopathological characteristics was also assessed. CD3⁺ and CD4⁺ TILs were detected in 100% of the samples. CD3⁺ was the predominant subset of TILs. PD-L1 was expressed in 53 of 61 (86%) patients when a score of ≥1 on tumor cells was considered positive and in 28 patients (45.2%) when a score of >5 on tumor cells was considered positive. PD-L1 mRNA levels were determined to be significantly correlated with PD-L1 protein expression. Survival analysis demonstrated that high CD4⁺ TILs were associated with improved overall survival (OS) and disease-free survival (DFS), and furthermore, the association of high PD-L1 expression with unfavorable OS and DFS was statistically significant. Multivariate analysis identified CD4⁺ TILs and PD-L1 as prognostic markers for HNSCC. The results of the present study suggested that increased CD4⁺ TILs in HNSCC may be associated with improved outcomes, while high expression of PD-L1 may indicate unfavorable OS and DFS; thus, these factors may serve as predictors of the response to immune checkpoint therapy.

In vitro characterization of a small molecule PD-1 inhibitor that targets the PD-l/PD-L1 interaction

Targeting the programmed cell death protein 1/programmed cell death ligand 1 (PD-1/PD-L1) axis with monoclonal antibodies (mAbs) represents a crucial breakthrough in anticancer therapy, but mAbs are limited by their poor oral bioavailability, adverse events in multiple organ systems, and primary, adaptive, and acquired resistance, amongst other issues. More recently, the advent of small molecule inhibitors that target the PD-1/PD-L1 axis have shown promising cellular inhibitory activity and the potential to counteract the disadvantages of mAbs. In this study, structure-based virtual screening identified small molecule inhibitors that effectively inhibited the PD-1/PD-L1 interaction. Six of those small molecule inhibitors were applied to cell-based experiments targeting PD-1: CH-1, CH-2, CH-3, CH-4, CH-5, and CH-6. Of all 6, CH-4 displayed the lowest cytotoxicity and strongest inhibitory activity towards the PD-1/PD-L1 interaction. The experiments revealed that CH-4 inhibited the interaction of soluble form PD-L1 (sPD-L1) with PD-1 surface protein expressed by KG-1 cells. Investigations into CH-4 analogs revealed that CH-4.7 effectively blocked the PD-1/sPD-L1 interaction, but sustained the secretion of interleukin-2 and interferon-γ by Jurkat cells. Our experiments revealed a novel small molecule inhibitor that blocks the interaction of PD-1/sPD-L1 and potentially offers an alternative PD-1 target for immune checkpoint therapy.

A systematic review of phase II trials exploring anti-PD-1/PD-L1 combinations in patients with solid tumors

BACKGROUND

A high number of combinations of PD-1/PD-L1 inhibitors with other anti-cancer therapies are in clinical development. The usefulness of phase II trials in evaluating their efficacy and safety is unclear.

MATERIALS AND METHODS

We performed a systematic search on PubMed and Cochrane Library for phase II trials of PD-1/PD-L1 inhibitors in combination with other anti-cancer therapies (systemic therapy and/or radiotherapy) published between January 1st 2018 and December 31st 2020. Study design, primary endpoint and main outcomes were registered for each paper.

RESULTS

119 articles reporting on 65 regimens were included in our analysis. Backbone agents were more frequently PD-1 inhibitors (pembrolizumab = 47, nivolumab = 41, camrelizumab = 3) followed by anti-PD-L1 (durvalumab = 19, atezolizumab = 6, avelumab = 3). Therapeutic partners were other immunotherapeutic agents (n = 46), targeted therapies (n = 40), chemotherapy (n = 22) or radiotherapy (n = 11). The majority of articles reported on single-arm trials (n = 87, 73%) and response rate was the most frequent primary endpoint (n = 69, 58%). Objective responses, registered in 109 (92%) articles, ranged between 0% and 91%. The incidence of grade 3 or higher treatment-related adverse events, clearly reported in 97 (82%) articles, spanned from 0 to 100%. Five combinations received regulatory approval by Food and Drug Administration or European Medicine Agency for 9 different indications, based on the results of a phase II trial (n = 3) or on a confirmatory phase III trial (n = 6).

CONCLUSIONS

The landscape of phase II trials evaluating PD-1/PD-L1 inhibitors with other anticancer therapies is heterogeneous. Combinations of two immunotherapeutic agents have been the most investigated. Only a minority of indications (8%) granted regulatory approval.

Quercetin inhibiting the PD-1/PD-L1 interaction for immune-enhancing cancer chemopreventive agent

Targeting the PD-1/PD-L1 immune checkpoints has achieved significant positive results in the treatment of multiple cancers. Quercetin is one of the most abundant dietary flavonoids found in various vegetables and fruits, and has a wide range of biological activities including immunomodulation. Here we report that quercetin dihydrate was screened and shown to inhibit the PD-1/PD-L1 interaction. Treatment with quercetin dihydrate promoted the killing activity of T cells on MDA-MB-231 and NCI-H460 cancer cells. Experiments using the xenograft mouse model showed that the growth rate of tumor volumes and masses in the quercetin dihydrate-treated mice were decreased. Immunohistochemistry of the tumors showed that CD8, GZMB, and IFN-γ were increased in the quercetin dihydrate-treated mice. These results suggest that quercetin dihydrate attenuates the inhibitory effect of PD-L1 on T cells by inhibiting the PD-1/PD-L1 interaction, which has an exciting potential to be used as a cancer chemopreventive agent.

PD-1/PD-L1 Checkpoint Inhibitors in Tumor Immunotherapy

Programmed death protein 1 (PD1) is a common immunosuppressive member on the surface of T cells and plays an imperative part in downregulating the immune system and advancing self-tolerance. Its ligand programmed cell death ligand 1 (PDL1) is overexpressed on the surface of malignant tumor cells, where it binds to PD1, inhibits the proliferation of PD1-positive cells, and participates in the immune evasion of tumors leading to treatment failure. The PD1/PDL1-based pathway is of great value in immunotherapy of cancer and has become an important immune checkpoint in recent years, so understanding the mechanism of PD1/PDL1 action is of great significance for combined immunotherapy and patient prognosis. The inhibitors of PD1/PDL1 have shown clinical efficacy in many tumors, for example, blockade of PD1 or PDL1 with specific antibodies enhances T cell responses and mediates antitumor activity. However, some patients are prone to develop drug resistance, resulting in poor treatment outcomes, which is rooted in the insensitivity of patients to targeted inhibitors. In this paper, we reviewed the mechanism and application of PD1/PDL1 checkpoint inhibitors in tumor immunotherapy. We hope that in the future, promising combination therapy regimens can be developed to allow immunotherapeutic tools to play an important role in tumor treatment. We also discuss the safety issues of immunotherapy and further reflect on the effectiveness of the treatment and the side effects it brings.

Ultrasound (US)-activated redox dyshomeostasis therapy reinforced by immunogenic cell death (ICD) through a mitochondrial targeting liposomal nanosystem

Introduction: An imbalance in redox homeostasis consistently inhibits tumor cell proliferation and further causes tumor regression. Thus, synchronous glutaminolysis inhibition and intracellular reactive oxygen (ROS) accumulation cause severe redox dyshomeostasis, which may potentially become a new therapeutic strategy to effectively combat cancer. Methods: Mitochondrial-targeting liposomal nanoparticles (abbreviated MLipRIR NPs) are synthesized by the encapsulation of R162 (inhibitor of glutamate dehydrogenase 1 [GDH1]) and IR780 (a hydrophobic sonosensitizer) within the lipid bilayer, which are exploited for ultrasound (US)-activated tumor dyshomeostasis therapy reinforced by immunogenic cell death (ICD). Results: R162 released from MLipRIR NPs disrupts the glutaminolysis pathway in mitochondria, resulting in downregulated enzymatic activity of glutathione peroxidase (GPx). In addition, loaded IR780 can generate high levels of ROS under US irradiation, which not only interrupts mitochondrial respiration to induce apoptosis but also consumes local glutathione (GSH). GSH depletion accompanied by GPx deactivation causes severe ferroptosis of tumor cells through the accumulation of lipid peroxides. Such intracellular redox dyshomeostasis effectively triggers immunogenic cell death (ICD), which can activate antitumor immunity for the suppression of both primary and distant tumors with the aid of immune checkpoint blockade. Conclusions: Taking advantage of multimodal imaging for therapy guidance, this nanoplatform may potentiate systemic tumor eradication with high certainty. Taken together, this state-of-the-art paradigm may provide useful insights for cancer management by disrupting redox homeostasis.

The role of lncRNAs and circRNAs in the PD-1/PD-L1 pathway in cancer immunotherapy

Cancer immunotherapy has recently shown promising antitumor effects in various types of tumors. Among all immune checkpoints, the PD-1/PD-L1 pathway plays an important role in the immune evasion of tumor cells, making it a potent target in antitumor immunity. Accordingly, antibodies targeting the PD-1/PD-L1 pathway have been developed to attack tumor cells; however, resistance to immune therapy remains to be solved. Hence, identification of the underlying modulators of the PD-1/PD-L1 pathway is of significant importance to understand the mechanisms of antitumor immunotherapy. Long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) have been identified to regulate the PD-1/PD-L1 pathway, leading to participation in the immune response and immunotherapy. Therefore, this review focuses on the functions of lncRNAs and circRNAs in regulation of the PD-1/PD-L1 axis in tumorigenesis and tumor progression. We hope this review will stimulate research to supply more precise and effective cancer immune checkpoint therapies for a large number of tumors.

Immunotherapy in Breast Cancer Patients: A Focus on the Use of the Currently Available Biomarkers in Oncology

Immune checkpoint inhibitors (ICIs) have remarkably modified the way solid tumors are managed, including breast cancer. Unfortunately, only a relatively small number of breast cancer patients significantly respond to these treatments. To maximize the immunotherapy benefit in breast cancer, several efforts are currently being put forward for the identification of i) the best therapeutic strategy (i.e. ICI monotherapy or in association with chemotherapy, radiotherapy, or other drugs); ii) the optimal timing for administration (e.g. early/advanced stage of disease; adjuvant/neoadjuvant setting); iii) the most effective and reliable predictive biomarkers of response (e.g. tumor-infiltrating lymphocytes, programmed death-ligand 1, microsatellite instability associated with mismatch repair deficiency, and tumor mutational burden). This article reviews the impacts and gaps in the characterization of immune-related biomarkers raised by clinical and translational research studies with immunotherapy treatments. Particular emphasis has been put on the documented evidence of significant clinical benefits of ICI in different randomized clinical trials, along with preanalytical and analytical issues in predictive biomarkers pathological assessment.

Hepatocellular cancer therapy in patients with HIV infection: Disparities in cancer care, trials enrolment, and cancer-related research

In the highly active antiretroviral therapy (HAART) era, hepatocellular carcinoma (HCC) is arising as a common late complication of human immunodeficiency virus (HIV) infection, with a great impact on morbidity and mortality. Though HIV infection alone may not be sufficient to promote hepatocarcinogenesis, the complex interaction of HIV with hepatitis is a main aspect influencing HCC morbidity and mortality.

Data about sorafenib effectiveness and safety in HIV-infected patients are limited, particularly for patients who are on HAART. However, in properly selected subgroups, outcomes may be comparable to those of HIV-uninfected patients. Scarce data are available for those other systemic treatments, either tyrosine kinase inhibitors, as well as immune checkpoint inhibitors (ICIs), which have been added to our therapeutic armamentarium. This review examines the influence of HIV infection on HCC development and natural history, summarizes main data on systemic therapies, offers some insight into possible mechanisms of T cell exhaustion and reversal of HIV latency with ICIs and issues about clinical trials enrollment. Nowadays, routine exclusion of HIV-infected patients from clinical trial participation is totally inappropriate, since it leaves a number of patients deprived of life-prolonging therapies.

Inhibition of PAI-1 Blocks PD-L1 Endocytosis and Improves the Response of Melanoma Cells to Immune Checkpoint Blockade

Immune checkpoint molecules, especially PD-1 and its ligand PD-L1, act as a major mechanism of cancer immune evasion. Although anti-PD-1/PD-L1 monotherapy increases therapeutic efficacy in melanoma treatment, only a subset of patients exhibits long-term tumor remission, and the underlying mechanism of resistance to PD-1/PD-L1 inhibitors remains unclear. In this study, we demonstrated that cell surface retention of PD-L1 is inversely correlated with PAI-1 expression in vitro, in vivo, and in clinical specimens. Moreover, extracellular PAI-1 induced the internalization of surface-expressed PD-L1 by triggering clathrin-mediated endocytosis. The endocytosed PD-L1 was transported to lysosomes for degradation by endolysosomal systems, resulting in the reduction of surface PD-L1. Notably, inhibition of PAI-1 by pharmacological inhibitor with tiplaxtinin led to elevated PD-L1 expression on the plasma membrane, both in vitro and in vivo. Strikingly, targeting PAI-1 by tiplaxtinin treatment synergizes with anti-PD-L1 immune checkpoint blockade therapy in a syngeneic murine model of melanoma. Our findings demonstrate a role for PAI-1 activity in immune checkpoint modulation by promoting surface PD-L1 for lysosomal degradation and provides an insight into the combination of PAI-1 inhibition and anti-PD-L1 immunotherapy as a promising therapeutic regimen for melanoma treatment.

Identification of a Sensitive Human Immunological Target of Aryl Hydrocarbon Receptor Activation: CD5+ Innate-Like B Cells

Xenobiotic-mediated activation of the aryl hydrocarbon receptor (AHR) is immunotoxic in a number of immune cell types, with the B cell being a well-established sensitive target. Recent advances have provided evidence that the B cell repertoire is a heterogeneous population, with subpopulations exhibiting vastly different cellular and functional phenotypes. Recent work from our laboratory identified the T cell specific kinase lck as being differentially regulated by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), which is a potent activator of AHR. While LCK is primarily expressed in T cells, a subset of CD5⁺ B cells also express LCK. CD5 positivity describes a broad class of B lymphocytes termed innate-like B cells (ILBs) that are critical mediators of innate immunity through constitutive secretion of polyvalent natural immunoglobulin M (IgM). We hypothesized that CD5⁺ ILBs may be sensitive to AHR-mediated immunotoxicity. Indeed, when CD5⁺ B cells were isolated from the CD19⁺ pool and treated with TCDD, they showed increased suppression of the CD40 ligand-induced IgM response compared to CD5^- B cells. Further, characterization of the CD5⁺ population indicated increased basal expression of AHR, AHR repressor (AHRR), and cytochrome p450 family 1 member a1 (CYP1A1). Indeed the levels of AHR-mediated suppression of the IgM response from individual donors strongly correlated with the percentage of the B cell pool that was CD5⁺, suggesting that CD5⁺ B cells are more sensitive to AHR-mediated impairment. Together these data highlight the sensitive nature of CD5⁺ ILBs to AHR activation and provide insight into mechanisms associated with AHR activation in human B cells.

Blocking TIM-3 in Treatment-refractory Advanced Solid Tumors: A Phase Ia/b Study of LY3321367 with or without an Anti-PD-L1 Antibody

PURPOSE

T-cell immunoglobulin and mucin-domain-containing molecule-3 (TIM-3) blunts anticancer immunity and mediates resistance to programmed death 1 (PD-1) and PD ligand 1 (PD-L1) inhibitors. We assessed a novel, first-in-class, TIM-3 mAb, LY3321367, alone or in combination with the anti-PD-L1 antibody, LY300054 in patients with advanced solid tumor.

PATIENTS AND METHODS

This open-label, multicenter, phase Ia/b study aimed to define the safety/tolerability and recommended phase II dose (RP2D) of LY3321367 with or without LY300054. Secondary objectives included pharmacokinetics/pharmacodynamics, immunogenicity, and efficacy. Biomarkers were assessed in exploratory analysis.

RESULTS

No dose-limiting toxicities were observed in the monotherapy (N = 30) or combination (N = 28) dose escalation. LY3321367 treatment-related adverse events (≥2 patients) included pruritus, rash, fatigue, anorexia, and infusion-related reactions. Dose-proportional increase in LY3321367 concentrations was not affected by either LY300054 or antidrug antibodies (observed in 50%-70% of patients). Pharmacokinetic/pharmacodynamic modeling indicated 100% target engagement at doses ≥600 mg. LY3321367 RP2D was 1,200 mg biweekly for four doses followed by 600 mg every 2 weeks thereafter. In the non-small cell lung cancer monotherapy expansion cohort, outcomes varied by prior anti-PD-1 therapy response status: anti-PD-1/L1 refractory patients [N = 23, objective response rate (ORR) 0%, disease control rate (DCR) 35%, progression-free survival (PFS) 1.9 months] versus anti-PD-1/L1 responders (N = 14, ORR 7%, DCR 50%, PFS 7.3 months). In combination expansion cohorts (N = 91), ORR and DCR were 4% and 42%; CD8 infiltration in paired biopsies increased in approximately half these patients.

CONCLUSIONS

LY3321367 exhibited acceptable safety profile with favorable pharmacokinetics/pharmacodynamics but only modest antitumor activity. The therapeutic relevance of TIM-3 blockade requires further investigation.

High Expression of PD-L1 Is Associated with Better Survival in Pancreatic/Periampullary Cancers and Correlates with Epithelial to Mesenchymal Transition

Periampullary cancers (PACs) are characterized by tumor-infiltrating lymphocytes (TILs), severe fibrosis, and epithelial to mesenchymal transition (EMT). The immune checkpoint marker programmed death-1 (PD-1) and its ligands 1 and 2 have gained popularity in cancers with TILs. Evidence suggests a strong relationship between immune checkpoint markers and EMT in cancers. Here, we evaluated the expression and prognostic significance of immune checkpoint and EMT markers in PAC using an automated image analyzer. Formalin-fixed, paraffin-embedded surgically excised PAC tissues from laboratory archives (1998–2014) were evaluated by immunohistochemical staining for PD-1, PD-L1, and PD-L2 in a tissue microarray. In total, 115 PAC patients (70 males and 45 females) with an average age of 63 years were analyzed. Location, gross type, size, radial resection margin, N-M stage, lymphatic invasion, vascular invasion, perineural invasion, histologically well-differentiated severe inflammation, and high PD-L1 expression were significantly associated with recurrence. Higher PD-L1 expression, but not PD-1 and PD-L2, was significantly related to better overall survival (OS) and disease-free survival (DFS). PD-L1 and PD-L2 were significantly related to EMT markers. Aside from other clinicopathologic parameters, high PD-L1 expression was significantly related to better OS and DFS of PAC patients. Moreover, immune checkpoint markers were significantly associated with EMT markers. Therefore, PD-L1 expression can be a good prognostic marker to guide future immune target-based therapies in PAC patients.

In vivo CART cell imaging: Paving the way for success in CART cell therapy

Chimeric antigen receptor T (CART) cells are a promising immunotherapy that has induced dramatic anti-tumor responses in certain B cell malignancies. However, CART cell expansion and trafficking are often insufficient to yield long-term remissions, and serious toxicities can arise after CART cell administration. Visualizing CART cell expansion and trafficking in patients can detect an inadequate CART cell response or serve as an early warning for toxicity development, allowing CART cell treatment to be tailored accordingly to maximize therapeutic benefits. To this end, various imaging platforms are being developed to track CART cells in vivo, including nonspecific strategies to image activated T cells and reporter systems to specifically detect engineered T cells. Many of these platforms are clinically applicable and hold promise to provide valuable information and guide improved CART cell treatment.