Contribution of the PD-L1/PD-1 pathway to T-cell exhaustion: an update on implications for chronic infections and tumor evasion

Correlation between PD-1/PD-L1 and RANKL/OPG in chronic apical periodontitis model of Sprague-Dawley rats

Chronic apical periodontitis (CAP) is characterized by inflammation and destruction of the apical periodontium that is of pulpal origin, appearing as an apical radiolucent area, and does not produce clinical symptoms. Little is known about whether the PD-1/PD-L1 ratio is associated with the balance between RANKL and OPG in CAP. The relationship between PD-1/PD-L1 and RANKL/OPG in CAP is investigated in this study. A CAP rat model was established using Sprague-Dawley rats. The pulp chambers were exposed to the oral cavity to allow bacterial contamination. The apical tissues of the bilateral mandibular first molars were analyzed for histological morphology using hematoxylin and eosin (H&E) staining. Immunohistochemistry and qRT-PCR were used to determine the expression of PD-1, PD-L1, OPG, and RANKL mRNA and proteins in periapical tissues and mandibular samples, respectively. The radiological images indicated a poorly defined low-density shadow and alveolar bone resorption after periodontitis induction. Histological analysis revealed an infiltration of inflammatory cells and alveolar bone resorption in the periapical tissues. Mandibular mRNA and periapical protein expression of PD-1, PD-L1, and RANKL was upregulated 7-28 days after periodontitis induction, while the expression of OPG was downregulated. No significant relationship was observed between PD-1/PD-L1 and RANKL/OPG at either mRNA or protein levels in CAP. There is an increased expression of PD-1, PD-L1, and RANKL and a decreased expression of OPG, indicating progression of CAP.

Tumor microenvironment governs the prognostic landscape of immunotherapy for head and neck squamous cell carcinoma: A computational model-guided analysis

Immune checkpoint inhibition (ICI) has emerged as a critical treatment strategy for squamous cell carcinoma of the head and neck (HNSCC) that halts the immune escape of the tumor cells. Increasing evidence suggests that the onset, progression, and lack of/no response of HNSCC to ICI are emergent properties arising from the interactions within the tumor microenvironment (TME). Deciphering how the diversity of cellular and molecular interactions leads to distinct HNSCC TME subtypes subsequently governing the ICI response remains largely unexplored. We developed a cellular-molecular model of the HNSCC TME that incorporates multiple cell types, cellular states, and transitions, and molecularly mediated paracrine interactions. An exhaustive simulation of the HNSCC TME network shows that distinct mechanistic balances within the TME give rise to the five clinically observed TME subtypes such as immune/non-fibrotic, immune/fibrotic, fibrotic only and immune/fibrotic desert. We predict that the cancer-associated fibroblast, beyond a critical proliferation rate, drastically worsens the ICI response by hampering the accessibility of the CD8+ killer T cells to the tumor cells. Our analysis reveals that while an Interleukin-2 (IL-2) + ICI combination therapy may improve response in the immune desert scenario, Osteopontin (OPN) and Leukemia Inhibition Factor (LIF) knockout with ICI yields the best response in a fibro-dominated scenario. Further, we predict Interleukin-8 (IL-8), and lactate can serve as crucial biomarkers for ICI-resistant HNSCC phenotypes. Overall, we provide an integrated quantitative framework that explains a wide range of TME-mediated resistance mechanisms for HNSCC and predicts TME subtype-specific targets that can lead to an improved ICI outcome.

Role of PD-1 in Skin Cancer: Molecular Mechanism, Clinical Applications, and Resistance

Skin cancer is a widespread worldwide health concern, manifesting in many subtypes such as squamous cell carcinoma, basal cell carcinoma, and melanoma. Although all these types occur frequently, they generally lack the possibility of being cured, emphasizing the importance of early discovery and treatment. This comprehensive study explores the role of programmed cell death protein 1 (PD-1) in skin cancer, focusing on its molecular mechanisms in immune regulation and its critical role in tumor immune evasion, while also clarifying the complexities of immune checkpoints in cancer pathogenesis. It critically evaluates the clinical applications of PD-1 inhibitors, spotlighting their therapeutic potential in treating skin cancer, while also addressing the significant challenge of resistance. This work further discusses the evolution of resistance mechanisms against PD-1 inhibitors and suggests potential approaches to mitigate these issues, thereby enhancing the effectiveness of these therapies. The study further highlights the current state of PD-1 targeted therapies and sets the stage for future research aimed at optimizing these treatments for better clinical outcomes in skin cancer.

A DPC Database Study on the Safety of Atezolizumab/Carboplatin/Etoposide in Extensive-Disease Small Cell Lung Cancer in Japanese Patients

INTRODUCTION

Atezolizumab, carboplatin, and etoposide (ACE) therapy is a standard of care for extensive-disease small cell lung cancer (SCLC); however, its safety data are scarce, limiting generalization to the Japanese population.

METHODS

This study aimed to compare the safety of ACE versus carboplatin and etoposide (CE) therapies in Japanese patients using the Diagnosis Procedure Combination (DPC) database by comparing the incidence of adverse events (AEs). Retrospective data on clinical background and AEs were extracted from the DPC database. Incidence rates and restricted mean survival times (RMSTs) up to 6 months were analyzed for 19 clinically important AEs. Covariates were adjusted using the inverse probability weighting method.

RESULTS

A total of 330,774 patients were identified using the International Statistical Classification of Diseases and Related Health Problems 10th Revision codes, of whom 277 were included in the ACE cohort and 478 in the CE cohort. Among the 19 AEs, the incidence of skin disorder and thyroid dysfunction was significantly higher in the ACE cohort compared with the CE cohort. The adjusted incidence rate ratios were 2.38 (95% confidence interval [CI] 1.04-5.43) for skin disorder and 6.92 (95% CI 2.00-23.89) for thyroid dysfunction. The adjusted RMST differences were - 8.2 days (95% CI - 16.0 to - 0.4 days) for skin disorder and - 8.8 days (95% CI - 15.7 to - 1.9 days) for thyroid dysfunction.

CONCLUSIONS

This study provides evidence regarding the safety of ACE combination therapy in Japanese clinical practice using the DPC database, with results comparable to those reported in pivotal clinical trials.

TRIAL REGISTRATION

UMIN Clinical Trials Registry ID UMIN000041508.

A DPC Database Study on the Safety of Atezolizumab/Bevacizumab/Carboplatin/Paclitaxel in Non-small Cell Lung Cancer in Japanese Patients

INTRODUCTION

Atezolizumab, bevacizumab, carboplatin, and paclitaxel (ABCP) combination therapy is a standard of care for advanced non-squamous non-small cell lung cancer (NSQ-NSCLC); however, the lack of safety data limits its clinical application in Japan.

METHODS

This study compared the safety of ABCP with that of bevacizumab, carboplatin, and paclitaxel (BCP) combination for the treatment of advanced NSQ-NSCLC in Japanese patients by evaluating the clinical background and incidence of adverse events (AEs) based on data extracted from the Diagnosis Procedure Combination (DPC) database. Incidence rates and restricted mean survival times (RMSTs) for up to 1 year were analyzed for 19 clinically important AEs. Covariates were adjusted using the inverse probability weighting method.

RESULTS

A search conducted using the International Statistical Classification of Diseases and Related Health Problems 10th Revision codes identified 350,987 patients, of whom 202 were included in the ABCP cohort and 232 in the BCP cohort. Among the 19 AEs, the incidence of skin disorder and febrile neutropenia (FN) was significantly higher in the ABCP cohort versus the BCP cohort. The adjusted incidence rate ratios were 2.65 [95% confidence interval (CI) 1.43-4.91] for skin disorder and 1.70 (95% CI 1.01-2.85) for FN. The adjusted RMST differences were - 64.2 days (95% CI - 93.0 to - 35.4 days) and - 46.0 days (95% CI - 73.5 to - 18.5 days) for skin disorder and FN, respectively. These results were comparable to those of other pivotal clinical trials.

CONCLUSIONS

The findings of this DPC database study highlight the safety of ABCP in Japanese clinical practice, and this methodology may facilitate more efficient research in real-world settings.

TRIAL REGISTRATION

UMIN Clinical Trials Registry ID UMIN000041507.

IL-21- and CXCL9-engineered GPC3-specific CAR-T cells combined with PD-1 blockade enhance cytotoxic activities against hepatocellular carcinoma

The application of CAR-T cells in solid tumors poses several challenges, including poor T cell homing ability, limited infiltration of T cells and an immunosuppressive tumor environment. In this study, we developed a novel approach to address these obstacles by designing GPC3-specific CAR-T cell that co-express IL-21 and CXCL9 (21 × 9 GPC3 CAR-T cells) and blocking the PD-1 expression on it. The proliferation, cell phenotype, cytokine secretion and cell migration of indicated CAR-T cells were evaluated in vitro. The cytotoxic activities of genetically engineered CAR-T cells were accessed in vitro and in vivo. Compared to conventional GPC3 CAR-T cells, the 21 × 9 GPC3 CAR-T cells demonstrated superior proliferation, cytokine secretion and chemotaxis capabilities in vitro. Furthermore, when combined with PD-1 blockade, the 21 × 9 GPC3 CAR-T cells exhibited enhanced proliferation, cytokine secretion and enrichment of effector T cells such as CTL, NKT and TEM cells. In xenograft tumor models, the PD-1 blocked 21 × 9 GPC3 CAR-T cells effectively suppressed HCC xenograft growth and increased T cell infiltration. Overall, our study successfully generated GPC3 CAR-T cells expressing both IL-21 and CXCL9, demonstrated that combining PD-1 blockade can further enhance CAR-T cell function by promoting proliferation, cytokine secretion, chemotaxis and antitumor activity. These findings present a hopeful and potentially effective strategy for GPC3-positive HCC patients.

The prognostic value of programmed death-ligand 1 (PD-L1) expression in resected colorectal cancer without neoadjuvant therapy - differences between antibody clones and cell types

BACKGROUND

Programmed death-ligand 1 (PD-L1) expression on tumor cells is associated with poor prognosis in several malignancies, while partly contradictory and inconclusive results have been presented for colorectal cancer (CRC). This study aimed to evaluate PD-L1 as a prognostic biomarker in CRC by comparing three different antibody clones.

METHODS

Patients surgically treated for CRC between January 1st, 2007, and December 31st, 2015, in Kalmar County, Sweden, were retrospectively included. Tissue microarrays from 862 primary tumors without neoadjuvant treatment were assessed for immunohistochemical expression of PD-L1 in tumor cells (TC) and immune cells (IC) using clones 73-10, SP263, and 22C3. Cox regression proportional hazard models were used to estimate hazard ratios for overall survival (OS) and disease-free interval (DFI) in univariable and multivariable analyses, with 1% and 5% set as cut-offs for positive expression in TC and IC respectively.

RESULTS

PD-L1 expression in TC was found in 89 (10%) cases for clone 73-10, 76 (9%) for clone SP263, and 38 (4%) for clone 22C3, while the numbers for IC were 317 (37%) cases for clone 73-10, 264 (31%) for clone SP263, and 89 (10%) for clone 22C3. PD-L1 expression in IC was associated with prolonged OS and DFI in univariable analysis for all three clones. The link to prolonged DFI remained in multivariable analysis for 73-10 and SP263, but only for 73-10 regarding OS. PD-L1 expression in TC was not prognostic of OS in any analysis, while it was associated with prolonged DFI for SP263, and a trend was seen for 73-10. The link to prolonged DFI remained for SP263 and was strengthened for 73-10 in multivariable analysis.

CONCLUSIONS

The prognostic value of PD-L1 expression in both IC and TC differs between antibody clones, with 73-10 and SP263 being more reliable for prognostic information than 22C3 in resected CRC.

Application of PARP inhibitors combined with immune checkpoint inhibitors in ovarian cancer

The advent of polyadenosine diphosphate ribose polymerase inhibitors (PARPi) has brought about significant changes in the field of ovarian cancer treatment. However, in 2022, Rucaparib, Olaparib, and Niraparib, had their marketing approval revoked for third-line and subsequent therapies due to an increased potential for adverse events. Consequently, the exploration of new treatment modalities remains imperative. Recently, the integration of PARPi with immune checkpoint inhibitors (ICIs) has emerged as a potential remedy option within the context of ovarian cancer. This article offers a comprehensive examination of the mechanisms and applications of PARPi and ICIs in the treatment of ovarian cancer. It synthesizes the existing evidence supporting their combined use and discusses key considerations that merit attention in ongoing development efforts.

Oncoviral Infections and Small Extracellular Vesicles

Small extracellular vesicles (sEV) are small membrane-bound nanovesicles with a size range below 200 nm that are released by all types of cells. sEV carry a diverse cargo of proteins, lipids, glycans, and nucleic acids that mimic the content of producer cells. sEV mediate intercellular communication and play a key role in a broad variety of physiological and pathological conditions. Recently, numerous reports have emerged examining the role of sEV in viral infections. A significant number of similarities in the sEV biogenesis pathways and the replication cycles of viruses suggest that sEV might influence the course of viral infections in diverse ways. Besides directly modulating virus propagation by transporting the viral cargo (complete virions, proteins, RNA, and DNA), sEV can also modify the host antiviral response and increase the susceptibility of cells to infection. The network of mutual interactions is particularly complex in the case of oncogenic viruses, deserving special consideration because of its significance in cancer progression. This review summarizes the current knowledge of interactions between sEV and oncogenic viruses, focusing on sEV abilities to modulate the carcinogenic properties of oncoviruses.

Beyond Immune Checkpoint Inhibitors: Emerging Targets in Melanoma Therapy

PURPOSE OF REVIEW

This review provides a comprehensive update on recent advancements in melanoma treatment by highlighting promising therapeutics with an aim to increase awareness of novel interventions currently in development.

RECENT FINDINGS

Over the last decade there has been considerable expansion of the previously available treatment options for patients with melanoma. In particular, novel immunotherapeutics have been developed to expand on the clinical advancements brought by BRAF targeting and immune checkpoint inhibitors. Despite the success of checkpoint inhibitors there remains an unmet need for patients that do not respond to treatment. This review delves into the latest advancements in novel checkpoint inhibitors, cytokines, oncolytic viruses, vaccines, bispecific antibodies, and adoptive cell therapy. Preclinical experiments and early-stage clinical trials studies have demonstrated promising results for these therapies, many of which have moved into pivotal, phase 3 studies.

Expression of PD-L1 Is Increased by Methionine Restriction Using Recombinant Methioninase in Human Colorectal Cancer Cells

BACKGROUND/AIM

It has been recently demonstrated that a methionine-restricted diet increases the response to immune checkpoint inhibitors (ICIs) via an increase in PD-L1 in a syngeneic mouse colorectal-cancer model. Our laboratory has developed recombinant methioninase (rMETase) to restrict methionine. The aim of the present study was to determine if rMETase can increase PD-L1 expression in a human colorectal cancer cell line in vitro.

MATERIALS AND METHODS

We evaluated the half-maximal inhibitory concentration (IC50) value of rMETase on HCT-116 human colorectal cancer cells. HCT-116 cells were treated with rMETase at the IC50 Western immunoblotting was used to compare PD-L1 expression in HCT-116 cells treated with and without rMETase.

RESULTS

The IC50 value of rMETase on HCT-116 was 0.79 U/ml. Methionine restriction using rMETase increased PD-L1 expression compared to the untreated control (p<0.05).

CONCLUSION

Methionine restriction with rMETase up-regulates PD-L1 expression in human colorectal cancer cells and the combination of rMETase and ICIs may have the potential to improve immunotherapy in human colorectal cancer.

MDM2/MDMX inhibition by Sulanemadlin synergizes with anti-Programmed Death 1 immunotherapy in wild-type p53 tumors

Immunotherapy has revolutionized cancer treatment but its efficacy depends on a robust immune response in the tumor. Silencing of the tumor suppressor p53 is common in tumors and can affect the recruitment and activation of different immune cells, leading to immune evasion and poor therapy response. We found that the p53 activating stapled peptide MDM2/MDMX inhibitor Sulanemadlin (ALRN-6924) inhibited p53 wild-type cancer cell growth in vitro and in vivo. In mice carrying p53 wild-type CT26.WT tumors, monotherapy with the PD-1 inhibitor DX400 or Sulanemadlin delayed tumor doubling time by 50% and 37%, respectively, while combination therapy decreased tumor doubling time by 93% leading to an increased median survival time. Sulanemadlin treatment led to increased immunogenicity and combination treatment with PD-1 inhibition resulted in an increased tumor infiltration of lymphocytes. This combination treatment strategy could potentially turn partial responders into responders of immunotherapy, expanding the patient target group for PD-1-targeting immunotherapy.

The Role of Programmed Cell Death Ligand 1 Expression in Pituitary Tumours: Lessons from the Current Literature

BACKGROUND

Programmed cell death-1 (PD-1) and PD ligand-1 (PD-L1) expression predict the biological behaviour, aggressiveness, and response to immune checkpoint inhibitors in different cancers. We reviewed the published data on PD-L1 expression in pituitary tumours from the perspective of its biological role and prognostic usefulness.

SUMMARY

A literature review focused on PD-L1 expression in pituitary tumours was performed. Six immunohistochemistry-based studies which assessed PD-L1 positivity in pituitary tumours were included, encompassing 704 patients. The cohort consisted of 384 (54.5%) nonfunctioning tumours and 320 (43.5%) functioning pituitary tumours. PD-L1 expression was positive in 248 cases (35.2%). PD-L1 positivity rate was higher in functioning than in nonfunctioning tumours (46.3% vs. 26.0%; p < 0.001) but also higher in growth hormone-secreting tumours (56.7%) and prolactinomas (53.6%) than in thyrotroph (33.3%) or corticotroph tumours (20.6%). While proliferative pituitary tumours showed higher rate of PD-L1 positivity than non-proliferative tumours (p < 0.001), no association with invasion or recurrence was found.

KEY MESSAGES

PD-L1 is expressed in a substantial number of pituitary tumours, predominantly in the functioning ones. PD-L1 positivity rates were significantly higher in proliferative pituitary tumours in comparison to non-proliferative tumours, but no differences were found concerning invasive or recurrent pituitary tumours. More studies following homogeneous and standardised methodologies are needed to fully elucidate the role and usefulness of PD-L1 expression in pituitary tumours.

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.

Associations of PD-1 and PD-L1 gene polymorphisms with cancer risk: a meta-analysis based on 50 studies

Programmed death-1 and its ligand-1 (PD-1/PD-L1), immune checkpoints proteins, play a crucial role in anti-tumor responses. A large number of studies have evaluated the relationships of PD-1/PD-L1 polymorphisms with risk of cancer, but evidence for the associations remains inconsistent. Therefore, we performed a meta-analysis to examine the associations between PD-1/PD-L1 single nucleotide polymorphisms (SNPs) and cancer predisposition. Results showed that PD-1.3 and PD-L1 rs17718883 were significantly correlated with overall cancer risk. PD-1.5 was prominently linked with cervical cancer (CC), non-small cell lung cancer (NSCLC), TC (thyroid cancer), brain tumor, AML (acute myelocytic leukemia) and UCC (urothelial cell carcinoma) risk, PD-1.9 with breast cancer (BC), AML, esophageal cancer (EC) and ovarian cancer (OC) risk, and PD-1.3 with colorectal cancer (CRC) and BCC (basal cell carcinoma) risk. PD-1.1 polymorphism slightly elevated BC and OC susceptibility, whereas the rs4143815 variant notably decreased the risk of gastric cancer (GC), hepatocellular carcinoma (HCC) and OC, but increased the risk of BC. PD-1.6 was closely linked with AML risk, PD-L1 rs2890658 with NSCLC, HCC and BC risk, rs17718883 with HCC and GC risk, rs10815225 with GC risk, and rs2297136 with NSCLC and HCC risk. Interestingly, the rs7421861, rs10815225, and rs10815225 markedly reduced cancer susceptibility among Asians. The rs7421861 polymrophism decreased cancer risk among Caucasians, rather than the rs10815225 elevated cancer risk. Our results supported that PD-1 and PD-L1 SNPs were dramatically correlated with cancer risk.

Efficacy of natural killer cell therapy combined with chemoradiotherapy in murine models of head and neck squamous cell carcinoma

BACKGROUND AIMS

Natural killer (NK) cell-based cancer immunotherapy is effective when combined with other treatment modalities such as irradiation and chemotherapy. NK cell's antitumor function to treat solid tumor, including head and neck squamous cell carcinoma (HNSCC), has been targeted recently. This study assessed NK cell recruitment in response to chemoradiation therapy (CRT) in HNSCC.

METHODS

Ex vivo expansion of NK cell, flow cytometry, cell viability assay, cytotoxicity assay, immunohistochemistry, and animal model were performed.

RESULTS

Mouse NK cells were recruited to the tumor site by CRT in a nude mouse model. Furthermore, expanded and activated human NK cells (eNKs) were recruited to the tumor site in response to CRT, and CRT enhanced the anti-tumor activity of eNK in an NOD/SCID IL-2Rγnull mouse model. Various HNSCC cancer cell lines exhibited different NK cell ligand activation patterns in response to CRT that correlated with NK cell-mediated cytotoxicity.

CONCLUSIONS

Identifying the activation patterns of NK cell ligands during CRT might improve patient selection for adjuvant NK cell immunotherapy combined with CRT. This is the first study to investigate the NK cell's antitumor function and recruitment with CRT in HNSCC mouse model.

Using protein geometry to optimize cytotoxicity and the cytokine window of a ROR1 specific T cell engager

T cell engaging bispecific antibodies have shown clinical proof of concept for hematologic malignancies. Still, cytokine release syndrome, neurotoxicity, and on-target-off-tumor toxicity, especially in the solid tumor setting, represent major obstacles. Second generation TCEs have been described that decouple cytotoxicity from cytokine release by reducing the apparent binding affinity for CD3 and/or the TAA but the results of such engineering have generally led only to reduced maximum induction of cytokine release and often at the expense of maximum cytotoxicity. Using ROR1 as our model TAA and highly modular camelid nanobodies, we describe the engineering of a next generation decoupled TCE that incorporates a "cytokine window" defined as a dose range in which maximal killing is reached but cytokine release may be modulated from very low for safety to nearly that induced by first generation TCEs. This latter attribute supports pro-inflammatory anti-tumor activity including bystander killing and can potentially be used by clinicians to safely titrate patient dose to that which mediates maximum efficacy that is postulated as greater than that possible using standard second generation approaches. We used a combined method of optimizing TCE mediated synaptic distance and apparent affinity tuning of the TAA binding arms to generate a relatively long but persistent synapse that supports a wide cytokine window, potent killing and a reduced propensity towards immune exhaustion. Importantly, this next generation TCE induced significant tumor growth inhibition in vivo but unlike a first-generation non-decoupled benchmark TCE that induced lethal CRS, no signs of adverse events were observed.

Targeted protein modification as a paradigm shift in drug discovery

Targeted Protein Modification (TPM) is an umbrella term encompassing numerous tools and approaches that use bifunctional agents to induce a desired modification over the POI. The most well-known TPM mechanism is PROTAC-directed protein ubiquitination. PROTAC-based targeted degradation offers several advantages over conventional small-molecule inhibitors, has shifted the drug discovery paradigm, and is acquiring increasing interest as over ten PROTACs have entered clinical trials in the past few years. Targeting the protein of interest for proteasomal degradation by PROTACS was the pioneer of various toolboxes for selective protein degradation. Nowadays, the ever-increasing number of tools and strategies for modulating and modifying the POI has expanded far beyond protein degradation, which phosphorylation and de-phosphorylation of the protein of interest, targeted acetylation, and selective modification of protein O-GlcNAcylation are among them. These novel strategies have opened new avenues for achieving more precise outcomes while remaining feasible and minimizing side effects. This field, however, is still in its infancy and has a long way to precede widespread use and translation into clinical practice. Herein, we investigate the pros and cons of these novel strategies by exploring the latest advancements in this field. Ultimately, we briefly discuss the emerging potential applications of these innovations in cancer therapy, neurodegeneration, viral infections, and autoimmune and inflammatory diseases.

The Role of Checkpoint Inhibitor Expression Directly on Exfoliated Cells from Bladder Cancer: A Narrative Review

Bladder cancer (BCa) is a common type of cancer that affects the urinary bladder. The early detection and management of BCa is critical for successful treatment and patient outcomes. In recent years, researchers have been exploring the use of biomarkers as a non-invasive and effective tool for the detection and monitoring of BCa. One such biomarker is programmed death-ligand 1 (PD-L1), which is expressed on the surface of cancer cells and plays a crucial role in the evasion of the immune system. Studies have shown that the PD-L1 expression is higher in BCa tumors than in healthy bladder tissue. Additionally, PD-L1 expression might even be detected in urine samples in BCa patients, in addition to the examination of a histological sample. The technique is being standardized and optimized. We reported how BCa patients had higher urinary PD-L1 levels than controls by considering BCa tumors expressing PD-L1 in the tissue specimen. The expression of PD-L1 in urinary BCa cells might represent both a diagnostic and a prognostic tool, with the perspective that the PD-L1 expression of exfoliate urinary cells might reveal and anticipate eventual BCa recurrence or progression. Further prospective and longitudinal studies are needed to assess the expression of PD-L1 as a biomarker for the monitoring of BCa patients. The use of PD-L1 as a biomarker for the detection and monitoring of BCa has the potential to significantly improve patient outcomes by allowing for earlier detection and more effective management of the disease.

Dual Synergistic Tumor-Specific Polymeric Nanoparticles for Efficient Chemo-Immunotherapy

Chemo-immunotherapy has made significant progress in cancer treatment. However, the cancer cell self-defense mechanisms, including cell cycle checkpoint and programmed cell death-ligand 1 (PD-L1) upregulation, have greatly hindered the therapeutic efficacy. Herein, norcantharidin (NCTD)-platinum (Pt) codelivery nanoparticles (NC-NP) with tumor-sensitive release profiles are designed to overcome the self-defense mechanisms via synergistic chemo-immunotherapy. NC-NP remains stable under normal physiological conditions but quickly releases 1,2-diaminocyclohexane-platinum(II) (DACHPt, a parent drug of oxaliplatin) and NCTD in response to the tumor acidity. NCTD inhibits protein phosphatase 2A (PP2A) activity to relieve cell cycle arrest and downregulates the tumor PD-L1 expression to disrupt the programmed cell death-1 (PD-1)/PD-L1 interaction, synergistically enhancing Pt-based chemotherapy and immunogenic cell death-induced immunotherapy. As a result, NC-NP exhibits potent synergistic cytotoxicity and promotes T cell recruitment to generate robust antitumor immune responses. The dual synergism exhibits potent antitumor activity against orthotopic 4T1 tumors, providing a promising chemo-immunotherapy paradigm for cancer treatment.

Mycobacteria modulate SUMOylation to suppresses protective responses in dendritic cells

Post translational modifications (PTMs) are exploited by various pathogens in order to escape host immune responses. SUMOylation is one of the PTMs which is involved in regulation of a variety of cellular responses. However, the effects of host SUMOylation on pathogenic bacteria largely remain elusive. We, therefore, investigated the role of SUMOylation in regulating defense responses in dendritic cells (DCs) during mycobacterial infection. Dendritic Cells of female BALB/c mice and THP-1 macrophages were used. Western blotting was performed to measure the expression of level of SUMO1, pSTAT1, pp38, pERK, Beclin-1, LC3, Bax and Cytochrome C. For bacterial burden confocal microscopy and CFU (Colony Forming Unit) were used. Flow cytometry was used for ROS and co-stimulatory molecules measurement. Cytokine level were measured using ELISA. We show that stimulation of Bone Marrow Derived Dendritic Cells (BMDCs) with mycobacterial antigen Rv3416 or live infection with Mycobacterium bovis BCG increases the SUMOylation of host proteins. Inhibition of SUMOylation significantly decreased intracellular bacterial loads in DCs. Additionally, inhibiting SUMOylation, induces protective immune responses by increasing oxidative burst, pro-inflammatory cytokine expression and surface expression of T cell co-stimulatory molecules, and activation of pSTAT1 and Mitogen Activated Protein Kinases (MAPK) proteins- pp38 and pERK. SUMOylation inhibition also increased apoptosis and autophagy in BMDCs. Intriguingly, mycobacteria increased SUMOylation of many of the above molecules. Furthermore, inhibiting SUMOylation in DCs primed T cells that in turn attenuated bacterial burden in infected macrophages. These findings demonstrate that SUMOylation pathway is exploited by mycobacteria to thwart protective host immune responses.

Pancreatic Ductal Adenocarcinoma Cells Regulate NLRP3 Activation to Generate a Tolerogenic Microenvironment

Defining feature of pancreatic ductal adenocarcinoma (PDAC) that participates in the high mortality rate and drug resistance is the immune-tolerant microenvironment which enables tumors to progress unabated by adaptive immunity. In this study, we report that PDAC cells release CSF-1 to induce nucleotide-binding domain, leucine-rich containing family, pyrin domain-containing-3 (NLRP3) activation in myeloid cells. Increased NLRP3 expression was found in the pancreas of patients with PDAC when compared with normal pancreas which correlated with the formation of the NLRP3 inflammasome. Using human primary cells and an orthotopic PDAC mouse model, we show that NLRP3 activation is responsible for the maturation and release of the inflammatory cytokine IL1β which selectively drives Th2-type inflammation via COX2/PGE2 induction. As a result of this inflammation, primary tumors were characterized by reduced cytotoxic CD8+ T-cell activation and increased tumor expansion. Genetic deletion and pharmacologic inhibition of NLRP3 enabled the development of Th1 immunity, increased intratumoral levels of IL2, CD8+ T cell–mediated tumor suppression, and ultimately limited tumor growth. In addition, we observed that NLRP3 inhibition in combination with gemcitabine significantly increased the efficacy of the chemotherapy. In conclusion, this study provides a mechanism by which tumor-mediated NLRP3 activation exploits a distinct adaptive immunity response that facilitates tumor escape and progression. Considering the ability to block NLRP3 activity with safe and small orally active molecules, this protein represents a new promising target to improve the limited therapeutic options in PDAC.

SIGNIFICANT

This study provides novel molecular insights on how PDAC cells exploit NLRP3 activation to suppress CD8 T-cell activation. From a translational perspective, we demonstrate that the combination of gemcitabine with the orally active NLRP3 inhibitor OLT1177 increases the efficacy of monotherapy.

Advancing Immunotherapies for HPV-Related Cancers: Exploring Novel Vaccine Strategies and the Influence of Tumor Microenvironment

The understanding of the relationship between immunological responses and cancers, especially those related to HPV, has allowed for the study and development of therapeutic vaccines against these neoplasias. There is a growing number of studies about the composition and influence of the tumor microenvironment (TME) in the progression or establishment of the most varied types of cancer. Hence, it has been possible to structure immunotherapy approaches based on therapeutic vaccines that are even more specific and directed to components of TME and the immune response associated with tumors. Among these components are dendritic cells (DCs), which are the main professional antigen-presenting cells (APCs) already studied in therapy strategies for HPV-related cancers. On the other hand, tumor-associated macrophages are also potential targets since the profile present in tumor infiltrates, M1 or M2, influences the prognosis of some types of cancer. These two cell types can be targets for therapy or immunomodulation. In this context, our review aims to provide an overview of immunotherapy strategies for HPV-positive tumors, such as cervical and head and neck cancers, pointing to TME immune cells as promising targets for these approaches. This review also explores the potential of immunotherapy in cancer treatment, including checkpoint inhibitors, cytokine immunotherapies, immunotherapy vaccines, and cell therapies. Furthermore, it highlights the importance of understanding the TME and its effect on the design and achievement of immunotherapeutic methods.

Progress in immune checkpoint inhibition in early-stage triple-negative breast cancer

INTRODUCTION

Immune checkpoint inhibitors have been particularly effective in treating cancers with robust immune microenvironments and have been successfully incorporated into the management of metastatic ER-negative and HER2-negative breast cancer. This has prompted investigation of immunotherapy in early-stage triple negative breast cancer (TNBC) to address the suboptimal clinical outcomes and limited therapeutic options.

AREAS COVERED

This review highlights the studies examining the use of neoadjuvant immunotherapy with standard chemotherapy in the management of early-stage TNBC and explores ongoing areas of study including the role of adjuvant checkpoint inhibition and novel combination therapies with immunotherapy.

EXPERT OPINION

The current standard of care for early-stage ER-negative, HER2-negative breast cancer measuring ≥2 cm or with lymph node involvement is neoadjuvant chemotherapy with pembrolizumab followed by ongoing pembrolizumab in the adjuvant setting to complete 1 year of total therapy as per the KEYNOTE-522 study. This approach is associated with improved pathologic complete response (pCR) rate and event free survival, irrespective of PD-L1 status. Many questions remain regarding the optimization of chemotherapy partner(s) for immunotherapy, necessity of adjuvant immunotherapy for patients who achieve pCR, inclusion of other therapies in the adjuvant setting (particularly capecitabine or olaparib), and use of adjuvant immunotherapy when it was not received in the neoadjuvant setting.

Immunohistochemical Profiling of PD-1, PD-L1, CD8, MSI, and p53 and Prognostic Implications in Advanced Serous Ovarian Carcinoma: A Retrospective Study

Advanced high-grade serous ovarian carcinoma is a serious malignant neoplasm with a late diagnosis and high mortality rate. Even when treated with standard therapy, such as surgery followed by carboplatin and paclitaxel chemotherapy, the prognosis remains unfavorable. Immunotherapy is a treatment alternative that requires further study. Therefore, we aimed to evaluate the expression of PD-1, PD-L1, CD8, MSI (MLH1, MSH2, MSH6, and PMS2), and p53 in the paraffin samples of high-grade serous ovarian carcinoma. A retrospective study of 28 southern Brazilian patients with advanced serous ovarian carcinoma (EC III or IV) was conducted between 2009 and 2020. The expression of these proteins was evaluated using immunohistochemistry, and the results were correlated with the patients' clinicopathological data. At diagnosis, the mean age was 61 years, and the most common clinical stage (60%) was EC III. Among the cases, 84.6% exhibited p53 overexpression, 14.8% had MSI, 92.0% were sensitive to platinum, and more than 50.0% relapsed after treatment. Patients with MSI had a lower CD8/PD-1 ratio and more relapses (p = 0.03). In conclusion, analysis of immunotherapeutic markers in paraffin-embedded advanced serous ovarian carcinoma samples is feasible and may assist in prognosis.

Recent Developments in Nanoparticle-Based Photo-Immunotherapy for Cancer Treatment

Phototherapy is an emerging approach for cancer treatment that is effective at controlling the growth of primary tumors. In the presence of light irradiation, photothermal and photodynamic agents that are delivered to tumor sites can induce local hyperthermia and the production of reactive oxygen species, respectively, that directly eradicate cancer cells. Nanoparticles, characterized by their small size and tunable physiochemical properties, have been widely utilized as carriers for phototherapeutic agents to improve their biocompatibility and tumor-targeted delivery. Nanocarriers can also be used to implement various codelivery strategies for further enhancing phototherapeutic efficiency. More recently, there has been considerable interest in augmenting the immunological effects of nanoparticle-based phototherapies, which can yield durable and systemic antitumor responses. This review provides an overview of recent developments in using nanoparticle technology to achieve photo-immunotherapy.

Vaccine plus microbicide effective in preventing vaginal SIV transmission in macaques

The human immunodeficiency virus epidemic continues in sub-Saharan Africa, and particularly affects adolescent girls and women who have limited access to antiretroviral therapy. Here we report that the risk of vaginal simian immunodeficiency virus (SIV)mac251 acquisition is reduced by more than 90% using a combination of a vaccine comprising V1-deleted (V2 enhanced) SIV envelope immunogens with topical treatment of the zinc-finger inhibitor SAMT-247. Following 14 weekly intravaginal exposures to the highly pathogenic SIVmac251, 80% of a cohort of 20 macaques vaccinated and treated with SAMT-247 remained uninfected. In an arm of 18 vaccinated-only animals without microbicide, 40% of macaques remained uninfected. The combined SAMT-247/vaccine regimen was significantly more effective than vaccination alone. By analysing immune correlates of protection, we show that, by increasing zinc availability, SAMT-247 increases natural killer cytotoxicity and monocyte efferocytosis, and decreases T-cell activation to augment vaccine-induced protection.

Tumor immunosuppression relief via acidity modulation combined PD-L1 siRNA for enhanced immunotherapy

The efficacy of immune checkpoint therapy is limited by the immunosuppressive tumor microenvironment (TME), and lactate, the most universal component of TME, has been rediscovered that plays important roles in the regulation of metabolic pathways, angiogenesis, and immunosuppression. Here, a therapeutic strategy of acidity modulation combined with programmed death ligand-1 (PD-L1) siRNA (siPD-L1) is proposed to synergistically enhance tumor immunotherapy. The lactate oxidase (LOx) is encapsulated into the hollow Prussian blue (HPB) nanoparticles (NPs) prepared by hydrochloric acid etching followed by the modification with polyethyleneimine (PEI) and polyethylene glycol (PEG) via sulfur bonds (HPB-S-PP@LOx), siPD-L1 is loaded via electrostatic adsorption to obtain HPB-S-PP@LOx/siPD-L1. The obtained co-delivery NPs can accumulate in tumor tissue with stable systemic circulation, and simultaneous release of LOx and siPD-L1 in intracellular high glutathione (GSH) environment after uptake by tumor cells without being destroyed by lysosome. Moreover, LOx can catalyze the decomposition of lactate in the hypoxic tumor tissue with the aid of oxygen release by the HPB-S-PP nano-vector. The results show that the acidic TME regulation via lactate consumption can improve the immunosuppressive TME, including revitalizing the exhausted CD8⁺ T cells and decreasing the proportion of immunosuppressive Tregs, and synergistically elevating the therapeutic effect of PD1/PD-L1 blockade therapy via siPD-L1. This work provides a novel insight for tumor immunotherapy and explores a promising therapy for triple-negative breast cancer.

Programmed Death-Ligand 1-Positive Squamous Cell Carcinoma Spontaneously Regressed after Percutaneous Needle Biopsy

Spontaneous lung cancer regression is a very rare course of disease. A 60-year-old male patient was admitted to our hospital with pneumonia and a 19 mm-sized nodule shadow in the S4 of the left lung on chest computed tomography (CT). A percutaneous needle biopsy was performed, and a diagnosis of programmed death-ligand 1-positive squamous cell lung carcinoma was made based on pathological findings. The patient was followed up with imaging because the lesion has reduced in size on chest CT. We report the possibility that cellular immune mechanisms triggered by needle biopsy contributed to spontaneous regression.

Prognostic value of pretreatment immune inflammation indices in patients with immune-related tumors

BACKGROUND

Pretreatment high levels of lactate dehydrogenase (LDH), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), monocyte-lymphocyte ratio (MLR), modified Glasgow prognostic scores (mGPS), prognostic nutritional index (PNI), and other prognostic biomarkers have been associated with poor overall survival (OS) in immune-related tumor types. Therefore, we explored a simple, inexpensive and effective method for cancer prognosis.

METHODS

Between March 2017 and June 2022, 111 individuals who had immunotherapy were retrospectively examined. Oncologic outcomes of patients with immune-related tumor types, include OS and progression-free survival (PFS), and response rates (RR).

RESULTS

Pretreatment ECOG (Eastern Cooperative Oncology Group) performance quality was independently linked with poor OS ECOG ≥2 (HR 4.80, 95% CI 2.57-8.96, p < .001) and inferior PFS (HR 3.31, 95% CI 2.023-5.445, p < .001). Additionally, a high LDH status prior to therapy was independently linked to an inferior OS (HR 1.004, 95% CI 1.001-1.007, p = .003) and inferior PFS (HR 1.004, 95% CI 1.002-1.006, p < .001). Higher MLR at baseline was a prognostic factor for both shorter PFS (HR = 3.691, 95% CI 1.582-8.610, p = .003) and OS (HR = 2.876, 95% CI 1.127-7.342, p = .027).

CONCLUSIONS

In our cohort, elevated pre-treatment MLR, LDH and ECOG ≥2 were associated with poor OS and PFS. Prospective studies need to determine the utility of them.

NOAEL cancer therapy: a tumor targetable docetaxel-inorganic polymer nanohybrid prevents drug-induced neutropenia

To date, cancer therapies largely consist of five pillars: surgery, radiation, chemotherapy, targeted therapy, and immunotherapy. Still, researchers are trying to innovate the current cancer therapies to pursue an ideal one without side effects. For developing such a therapy, we designed a chemically well-defined route to a PEG- and docetaxel (DTX)-conjugated inorganic polymer, polyphosphazene, named "polytaxel (PTX)" with a prolonged blood circulation time and tumor localization. Here, we conducted the proof-of-concept study of the ideal therapy in orthotopic and xenograft pancreatic cancer models. We found that the average tumor inhibition rates of PTX were similar to those of DTX without any DTX toxicity-related side effects, such as neutropenia and weight loss. In conclusion, PTX met the requirements of an ideal anticancer drug with high anticancer efficacy and 100% survival rate. PTX is expected to replace any existing anticancer therapies in clinical practice.

Reactivation of natural killer cells with monoclonal antibodies in the microenvironment of malignant neoplasms

Natural killer cells are critical players in the antitumor immune response due to their ability to destroy target cells through cytotoxic activity and other means. However, this response is inhibited in the tumor microenvironment, where a crippling hypoxic environment and several inhibitory molecules bind to NK cells to trigger an anergic state. Inhibitory receptors such as PD-1, NK2GA, KIR, TIGIT, and LAG-3 have been associated with inhibition of NK cells in multiple cancer types. Binding to these receptors leads to loss of cytotoxicity, lower proliferation and metabolic rates, and even apoptosis. While these receptors are important for avoiding auto-immunity, in a pathological setting like malignant neoplasms they are disadvantageous for the individual's immune system to combat cancer cells. The use of monoclonal antibodies to block these receptors contributes to cancer therapy by preventing the inhibition of NK cells. In this review, the impact of NK cell inhibition and activation on cancer therapy was summarized and an overview of the blockade of inhibitory pathways by monoclonal antibodies was provided.

Assessing the prognostic value of IMDC risk score for nivolumab-treated patients with renal cancer and malignant melanoma

BACKGROUND

The response of Renal Cell Cancer (RCC) to tyrosine kinase inhibitors (TKI) has been well established. Although these stratifications have been established for TKI response and prognosis, these parameters have recently been used to predict immunotherapy response in RCC. We aimed to use a combination of clinical parameters of International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) risk groups and metastatic sites at the time of diagnosis to predict the effectiveness of immune checkpoint inhibitors in malignant melanoma (MM).

METHOD

In this cross-sectional study, we retrospectively analyzed the demographic information, metastatic sites, and IMDC risk group data. The blood parameters were included in the first cycle of nivolumab treatment.

RESULTS

The OS was statistically different between the RCC and MM groups in terms of the IMDC. In univariate analysis of stage at diagnosis, CRP levels and bone and bone marrow metastases were confirmed to be prognostic factors in the MM population in terms of OS. Brain metastasis was a prognostic factor for RCC, whereas sex, line of treatment, LDH, bone, and splenic metastasis remained significant in patients with MM in terms of OS. Brain metastasis was prognostic in both cancer types in multivariate analysis in terms of PFS. In addition to brain metastasis, LDH levels and lung, liver, and splenic metastases also affect PFS in patients with MM undergoing nivolumab treatment.

CONCLUSION

In our study, the IMDC was confirmed to be a prognostic factor for MM. The IMDC groups were similar, except for the favorable RCC and MM groups. Different metastatic sites were prognostic, similar to the IMDC risk group in the MM group.

The exhaustion of lymphocytes is the main factor that decreases the sensitivity of QFT-GIT detection in silicosis

BACKGROUND

Tuberculosis infection is a major complication of silicosis, but there is no study on whether silicosis can affect the sensitivity of QuantiFERON-TB Gold In-Tube (QFT-GIT) assays. This study will analyze the relationship between silicosis and QFT-GIT, determine the main factor of the QFT-GIT sensitivity decrease in silicosis and explore the methods to increase the sensitivity.

METHODS

Silicosis patients with positive tubercle bacillus cultures were collected. The QFT-GIT, flow cytometry and blocking antibodies were used.

RESULTS

The sensitivity of QFT-GIT in silicosis patients (58.46%) was significantly decreased and the expression of PD-1 on T cells and CD56⁺NK cells in pulmonary tuberculosis combined with silicosis were higher than normal tuberculosis patients and silicosis only patients. Further analysis found that the ratio of PD-1⁺CD4⁺T and IFN-γwere negatively correlated and blockaded the PD-1 pathway with antibodies can restore the sensitivity of QFT-GIT in silicosis.

CONCLUSIONS

This is the first study to analyze the relationship between immune exhaustion and QFT-GIT in silicosis and found that the sensitivity of QFT-GIT was decreased by the expression of PD-1 on lymphocytes. Antibody blocking experiments increased the expression of IFN-γ and provided a new method to improve the sensitivity of QFT in silicosis. The study also found that silicosis can increase PD-1 expression. As PD-1 functions in infectious diseases, it will promote immune exhaustion in silicosis and lead to tuberculosis from latent to active infection. The study provided theoretical evidence for the diagnosis and immunotherapy of silicosis complications, and it has great value in clinical diagnostics and treatment.

A randomized phase 2 study of neoadjuvant carboplatin and paclitaxel with or without atezolizumab in triple negative breast cancer (TNBC) - NCI 10013

Atezolizumab with chemotherapy has shown improved progression-free and overall survival in patients with metastatic PD-L1 positive triple negative breast cancer (TNBC). Atezolizumab with anthracycline- and taxane-based neoadjuvant chemotherapy has also shown increased pathological complete response (pCR) rates in early TNBC. This trial evaluated neoadjuvant carboplatin and paclitaxel with or without atezolizumab in patients with clinical stages II-III TNBC. The co-primary objectives were to evaluate if chemotherapy and atezolizumab increase pCR rate and tumor infiltrating lymphocyte (TIL) percentage compared to chemotherapy alone in the mITT population. Sixty-seven patients (ages 25-78 years; median, 52 years) were randomly assigned - 22 patients to Arm A, and 45 to Arm B. Median follow up was 6.6 months. In the modified intent to treat population (all patients evaluable for the primary endpoints who received at least one dose of combination therapy), the pCR rate was 18.8% (95% CI 4.0-45.6%) in Arm A, and 55.6% (95% CI 40.0-70.4%) in Arm B (estimated treatment difference: 36.8%, 95% CI 8.5-56.6%; p = 0.018). Grade 3 or higher treatment-related adverse events occurred in 62.5% of patients in Arm A, and 57.8% of patients in Arm B. One patient in Arm B died from recurrent disease during the follow-up period. TIL percentage increased slightly from baseline to cycle 1 in both Arm A (mean ± SD: 0.6% ± 21.0%) and Arm B (5.7% ± 15.8%) (p = 0.36). Patients with pCR had higher median TIL percentages (24.8%) than those with non-pCR (14.2%) (p = 0.02). Although subgroup analyses were limited by the small sample size, PD-L1-positive patients treated with chemotherapy and atezolizumab had a pCR rate of 75% (12/16). The addition of atezolizumab to neoadjuvant carboplatin and paclitaxel resulted in a statistically significant and clinically relevant increased pCR rate in patients with clinical stages II and III TNBC. (Funded by National Cancer Institute).

Protein acylation: mechanisms, biological functions and therapeutic targets

Metabolic reprogramming is involved in the pathogenesis of not only cancers but also neurodegenerative diseases, cardiovascular diseases, and infectious diseases. With the progress of metabonomics and proteomics, metabolites have been found to affect protein acylations through providing acyl groups or changing the activities of acyltransferases or deacylases. Reciprocally, protein acylation is involved in key cellular processes relevant to physiology and diseases, such as protein stability, protein subcellular localization, enzyme activity, transcriptional activity, protein-protein interactions and protein-DNA interactions. Herein, we summarize the functional diversity and mechanisms of eight kinds of nonhistone protein acylations in the physiological processes and progression of several diseases. We also highlight the recent progress in the development of inhibitors for acyltransferase, deacylase, and acylation reader proteins for their potential applications in drug discovery.

Nomogram for predicting prognosis of patients with metastatic melanoma after immunotherapy: A Chinese population-based analysis

Background

Previous studies indicated the evidence that baseline levels of thyroid antibodies, thyroid status, and serum lactate dehydrogenase (LDH) and M stage may influence the prognosis of patients with advanced or metastatic melanoma treated with immune checkpoint inhibitors that targets programmed cell death-1 (PD-1) or programmed death ligand 1, which reported that dramatic improvements in survival rates were observed; however, the presence of controversy has prevented consensus from being reached. Study objectives were to develop a nomogram to identify several prognostic factors in Chinese patients with metastatic melanoma receiving immunotherapy.

Methods

This retrospective study included 231 patients from Sun Yat-sen University Cancer Center, and patients were split into internal cohort (n = 165) and external validation cohort (n = 66). We developed a nomogram for the prediction of response and prognosis on the basis of the levels of serum thyroid peroxidase antibody (A-TPO), free T3 (FT3), and LDH and M stage that were measured at the baseline of anti-PD-1 infusion. In addition, the follow-up lasted at least until 5 years after the treatment or mortality. RECIST v1.1 was used to classify treatment responses.

Results

Chi-square test showed that PD-1 antibody was more effective in patients with melanoma with high level baseline FT4 or earlier M stage. A multivariate Cox analysis showed that baseline FT3 (P = 0.009), baseline A-TPO (P = 0.016), and LDH (P = 0.013) levels and M stage (P < 0.001) independently predicted overall survival (OS) in patients with melanoma. The above factors are integrated, and a prediction model is established, i.e., nomogram. Survival probability area-under-the-curve values of 1, 2, and 3 years in the training, internal validation, and external validation cohorts showed the prognostic accuracy and clinical applicability of nomogram (training: 0.714, 0.757, and 0.764; internal validation: 0.7171963, 0.756549, and 0.7651486; external validation: 0.748, 0.710, and 0.856). In addition, the OS of low-risk (total score ≤ 142.65) versus high-risk (total score > 142.65) patients varied significantly in both training group (P < 0.0001) and external validation cohort (P = 0.0012).

Conclusions

According to this study, baseline biomarkers are associated with response to immunotherapy and prognosis among patients with metastatic melanoma. Treatment regimens can be tailor-made on the basis of these biomarkers.

Modifying factors of PD-L1 expression on tumor cells in advanced non-small-cell lung cancer

BACKGROUND

Programmed death ligand-1 (PD-L1) expression predicts immunotherapy utility in nononcogenic addictive lung adenocarcinoma (ADC). However, its reproducibility and reliability may be compromised outside clinical trials. This study aimed to evaluate factors associated with PD-L1 expression in lung ADC.

METHODS

This observational study assessed 547 tumor samples with advanced lung ADC from January 2016 to December 2020 in a single cancer institution. Tumor samples were stained by at least one approved PD-L1 clone, SP263 (Ventana) or 22C3 (Dako), and stratified in tumor proportion score (TPS) <1%, 1-49%, or ≥50%.

RESULTS

Of all the tumor samples, positive PD-L1 staining was higher in poorly differentiated tumors (67.3% vs. 32.7%, p < 0.001). Analytical factors associated with a PD-L1 high expression (TPS ≥ 50%) were the SP263 clone (19.6% vs. 8.2%, p < 0.001), time of archival tumor tissue <12 months (15.3% vs. 3.8%, p = 0.024), whenever the analysis was performed in the most recent years (2019-2020) (19.0% vs. 8.3%, p < 0.001), and whenever the analysis was performed by pathologists in the academic setting (Instituto Nacional de Cancerologia, INCan) (19.9% vs. 11.9%, p = 0.001). In the molecular analysis, EGFR wild-type tumors had an increased proportion of PD-L1 positive and PD-L1 high cases (60.2% vs. 47.9%, p = 0.006 and 17.4% vs.8.5%, p = 0.004). A moderate correlation (r = 0.69) in the PD-L1 TPS% was observed between the two different settings (INCan vs. external laboratories).

CONCLUSION

Clinicopathological factors were associated with an increased PD-L1 positivity rate. These differences were significant in the PD-L1 high group and associated with the academic setting, the SPS263 clone, time of archival tumor tissue <12 months, and a more recent period in the PD-L1 analysis.

Promise and Challenges of Checkpoint Inhibitor Therapy for Progressive Multifocal Leukoencephalopathy in HIV

PURPOSE OF REVIEW

Progressive multifocal leukoencephalopathy (PML) is a severe opportunistic infection that remains an important cause of morbidity and mortality in people living with HIV (PLWH). Immune checkpoint molecules are negative regulators of the immune response that have been targeted as a strategy to bolster anti-viral immunity in PML, with varied outcomes reported. While initiation and optimization of antiretroviral therapy remains the standard of care in HIV-related PML, the specific opportunities and risks for checkpoint blockade in these cases should be explored.

RECENT FINDINGS

As of April 15, 2022, only 5 of the 53 total published cases of PML treated with checkpoint blockade had underlying HIV infection; four of these had a favorable outcome. The risk of promoting immune reconstitution inflammatory syndrome is a major concern and underscores the importance of patient selection and monitoring. Checkpoint blockade warrants further exploration as a potentially promising option for treatment escalation in HIV-related PML.

The emerging role of immunotherapy in the treatment of anal cancer

For decades, chemoradiotherapy for early-stage disease and systemic chemotherapy for advanced disease have represented the mainstay of treatment for anal cancer. Over the last few years, however, the advent of immunotherapy has opened interesting therapeutic perspectives, with the establishment of new standards of care, and the development of clinical trials that may further shape the treatment algorithm for this tumour. In this review article, we discuss the rationale behind the use of immunotherapy for anal cancer and provide an overview of the available clinical data and ongoing efforts to build on these.

TERC suppresses PD-L1 expression by downregulating RNA binding protein HuR

TERC is the RNA component of telomerase, and provides a template for TERT to synthesize telomere repeats at chromosome ends. Increasing evidence has revealed that TERC is involved in other biological processes beyond telomerase. Here, we found that the expression level of TERC is negatively correlated with PD-L1 and that ectopic expression of TERC but not TERT in ALT cells significantly inhibits PD-L1, suggesting that TERC suppresses PD-L1 expression in a telomerase-independent manner. Mechanistically, instead of regulating PD-L1 mRNA directly, TERC accelerates PD-L1 mRNA degradation by inhibiting the expression of HuR, which binds to the 3'UTR of PD-L1 mRNA and maintains its stability. We also found that the small molecule AS1842856, a FoxO1 inhibitor, promotes TERC expression and reverses the PD-L1 upregulation caused by chemotherapy, providing a potential combination cancer therapy that avoids cancer immune escape during chemotherapy.

Successes and failures of immunotherapy for gastric cancer

Many exploratory clinical studies have been conducted on immune checkpoint inhibitors (ICIs) as new therapeutic approaches for the first-line treatment of patients with advanced gastric cancer. Despite varying interpretations of the successes and failures of this clinical research, most analyses have focused on the results from the perspective of exploring the superiority of immunotherapy. Consequently, the role of chemotherapy as an important partner of immunotherapy in first-line combination therapy regimens for gastric cancer has attracted less attention. Here, we explore and analyze first-line immunotherapies for gastric cancer from the perspective of chemotherapy, to understand reasons for the failure of studies and to indicate directions for future clinical research.

Dostarlimab an Inhibitor of PD-1/PD-L1: A New Paradigm for the Treatment of Cancer

Immunomodulation checkpoints usually adopted by healthy cells by tumors might cause an imbalance between host surveillance and tumor progression. Several tumors are incredibly resistant to standard treatment. The dynamic and long-lasting tumor regressions caused by antibodies targeting the PD-1/PD-L1 checkpoint have suggested a rebalancing of the host-tumor relationship. Checkpoint antibody inhibitors, like anti-PD-1/PD-L1, are unique inhibitors that reduce tumor growth by modulating the interaction between immune cells and tumor cells. These checkpoint inhibitors are swiftly emerging as a highly promising strategy for treating cancer because they produce impressive antitumor responses while having a limited number of adverse effects. Over the past several years, numerous checkpoint antibody inhibitors pointing to PD-1, PDL-1, and CTLA-4 have been available on the market. Despite its enormous success and usefulness, the anti-PD treatment response is restricted to certain kinds of cancer. This restriction can be attributed to the inadequate and diverse PD-1 expression in the tumor (MET) micro-environment. Dostarlimab (TSR-042), a drug that interferes with the PD-1/PD-L1 pathway, eliminates a crucial inhibitory response of an immune system and, as a result, has the potential to cause severe or deadly immune-mediated adverse effects. As cancer immunotherapy, dostarlimab enhances the antitumor immune response of the body.

Comparison of PD-L1 tumor cell expression with 22C3, 28-8, and SP142 IHC assays across multiple tumor types

BACKGROUND

Multiple PD-L1 immunohistochemistry (IHC) assays, including DAKO 22C3, DAKO 28-8, and Ventana SP142 PD-L1 IHC assays, have been approved by the Food and Drug Administration as a companion diagnostic (CDx) for various antiprogrammed death-1 and antiprogrammed death ligand 1 (PD-L1) based cancer immunotherapies. Here we present 22C3, 28-8, and SP142 analysis of 418 tumor specimens encountered in routine clinical practice.

METHODS

All specimens were tested with 22C3, 28-8, and SP142 assays following the manufacturer's established staining protocols.

RESULTS

The same PD-L1 status (defined as tumor cell expression (TC) scores with all three assays ≥1% or all &lt;1%) was observed in 60.0% (251/418) tumor specimens (45.9% (192/418) were triple negative and 14.1% (59/418) were triple positive). A total of 54.1% (226/418) tumor cases were positive with at least one IHC assay (94.2% (213/226), 77.0% (174/226), and 28.8% (65/226) of these were positive for 22C3, 28-8 and SP142, respectively). Among the 40.0% (167/418) tumor cases that showed a different PD-L1 status, 62.3% (104/167) were 22C3+/28-8+/SP142-, and 28.7% (48/167) were 22C3+/28-8-/SP142-. The same PD-L1 status with all three antibody clones was observed in 48.7% (97/199) of NSCLC cases, and among these, 54.6% (53/97) were triple negative and 45.4% (44/97) triple positive. A total of 73.4% (146/199) NSCLC cases were positive with at least one IHC assay (95.2% (n=139/146), 82.2% (n=120/146), and 32.2% (n=47/146) were positive for 22C3, 28-8, and SP142, respectively). Among the 51.3% (102/199) NSCLC cases that showed a different status among the three IHC assays, 67.6% (69/102) were 22C3+/28-8+/SP142-, and 23.5% (24/102) were 22C3+/28-8-/SP142-. A total of 81.1% (43/53) lung squamous cell carcinoma, 72.1% (88/122) of lung adenocarcinoma, 69.6% (16/23) of non-small cell lung cancer (NSCLC) not otherwise specified (NOS), and 50.0% (4/8) of small cell lung carcinoma cases were positive with at least one IHC assay.

CONCLUSIONS

Our data suggest that 22C3 is the most sensitive PD-L1 IHC assay for tumor cell expression, followed by 28-8 and in turn by SP-142. These findings represent an additional factor for clinical teams to consider when deciding which PD-L1 IHC assay (and in turn which CDx-associated PD-L1 based immunotherapy) is most appropriate for each individual patient.

Development of Surface Chemical Strategies for Synthesizing Redox-Responsive Diatomite Nanoparticles as a Green Platform for On-Demand Intracellular Release of an Antisense Peptide Nucleic Acid Anticancer Agent

Redox-responsive silica drug delivery systems are synthesized by aeco-friendly diatomite source to achieve on-demand release of peptide nucleic acid (PNA) in tumor reducing microenvironment, aiming to inhibit the immune checkpoint programmed cell death 1 receptor/programmed cell death receptor ligand 1 (PD-1/PD-L1) in cancer cells. The nanoparticles (NPs) are coated with polyethylene glycol chains as gatekeepers to improve their physicochemical properties and control drug release through the cleavable disulfide bonds (S-S) in a reductive environment. This study describes different chemical conditions to achieve the highest NPs' surface functionalization yield, exploring both multistep and one-pot chemical functionalization strategies. The best formulation is used for covalent PNA conjugation via the S-S bond reaching a loading degree of 306 ± 25 µg _PNA mg^-1 _DNPs . These systems are used for in vitro studies to evaluate the kinetic release, biocompatibility, cellular uptake, and activity on different cancer cells expressing high levels of PD-L1. The obtained results prove the safety of the NPs up to 200 µg mL^-1 and their advantage for controlling and enhancing the PNA intracellular release as well as antitumor activity. Moreover, the downregulation of PD-L1 observed only with MDA-MB-231 cancer cells paves the way for targeted immunotherapy.

Therapeutic Applications of the CRISPR-Cas System

The clustered regularly interspaced palindromic repeat (CRISPR)-Cas system has revolutionized genetic engineering due to its simplicity, stability, and precision since its discovery. This technology is utilized in a variety of fields, from basic research in medicine and biology to medical diagnosis and treatment, and its potential is unbounded as new methods are developed. The review focused on medical applications and discussed the most recent treatment trends and limitations, with an emphasis on CRISPR-based therapeutics for infectious disease, oncology, and genetic disease, as well as CRISPR-based diagnostics, screening, immunotherapy, and cell therapy. Given its promising results, the successful implementation of the CRISPR-Cas system in clinical practice will require further investigation into its therapeutic applications.

Biphenyl-based small molecule inhibitors: Novel cancer immunotherapeutic agents targeting PD-1/PD-L1 interaction

The immune checkpoint proteins are those key to the body's immunity which can either boost the immune system to protect the body from pathogens; or suppress the body's immunity system for the goal of self-tolerance. Cancer cells have evolved some mechanisms to boost the immuno-inhibitory checkpoints to bypass the immune system of the body. The binding of Programmed Cell Death-1 (PD-1) protein with its ligand Programmed Cell Death Ligand-1 (PD-L1) promotes this kind of immune-inhibitory signal. The discovery of immune checkpoint inhibitors was started in the early 21st century; with some success through monoclonal antibodies, peptides, and small molecules. Being the most reliable and safest way to target immune checkpoints, the scientific community is exploring possibilities to develop small molecule inhibitors. Among the different scaffolds of the small molecule, the most exposed and researched core molecule is Biphenyl-based scaffolds. We have described all of the possible biphenyl-based small molecules in this article, as well as their interactions with various amino acids in the binding cavity. The link between the in silico, in vitro, and in vivo activities of the PD-1/PD-L1 inhibitors are well connected. The Tyr56, Met115, Ala121, and Asp122 were detected as the crucial amino acids of the PD-1/PD-L1 inhibition. Additionally, a detailed binding pocket analysis of the PD-L1 receptor was carried out, where it was observed and confirmed that the binding pocket is tunnel-shaped and hydrophobic in nature. Finally, the structure-activity relationship of the biphenyl-based small molecule inhibitors was developed based on their activity and the binding interactions.

PD-1 blockage combined with vaccine therapy can facilitate immune infiltration in tumor microenvironment of Lynch syndrome colon cancer

Background: Lynch syndrome is a genetic disease resulting from mismatch repair gene mutation. Vaccine therapy can enhance the immunogenicity of Lynch syndrome and improve the therapeutic efficacy of immunotherapy. However, there is no approved Lynch syndrome vaccine coming onto the market.

Methods: Herein, we used gene knockdown method to construct Lynch syndrome cell model, paving way for us to develop Lynch syndrome tumor lysate vaccine. Then the isograft technique was employed for constructing the tumor-bearing mouse model of Lynch syndrome. And this isograft model was treated with PD-1 monoclonal antibody and tumor vaccine, respectively. Flow cytometry was used for detecting the proportion of immune cells and immunosuppressive cells, and ELISA was used for detecting the contents of chemokines and cytokines in the blood circulation system and tumor tissues of mice. Finally, IHC was used to detect the effects of tumor vaccines as well as PD-1 antibody on tumor tissue proliferation and angiogenesis.

Results: The results demonstrated that tumor vaccine could prolong the overall survival of mice, and improve the disease-free survival rate of mice. The vaccine could increase the proportion of inflammatory cells and decrease the proportion of anti-inflammatory cells in the blood circulation system of mice. In addition, tumor vaccine could also improve inflammatory infiltration in the tumor microenvironment and reduce the proportion of immunosuppressive cells. The results of IHC showed that tumor vaccine could inhibit angiogenesis and tumor cell proliferation in mouse tumor tissues.

Conclusion: In colon cancer associated with Lynch syndrome, tumor vaccine can hinder the growth of tumor cells, and assist immunotherapy whose therapeutic effect on this kind of cancer is thus enhanced.

Potential of Black Phosphorus in Immune-Based Therapeutic Strategies

Black phosphorus (BP) consists of phosphorus atoms, an essential element of bone and nucleic acid, which covalently bonds to three adjacent phosphorus atoms to form a puckered bilayer structure. With its anisotropy, band gap, biodegradability, and biocompatibility properties, BP is considered promising for cancer therapy. For example, BP under irradiation can convert near-infrared (NIR) light into heat and reactive oxygen species (ROS) to damage cancer cells, called photothermal therapy (PTT) and photodynamic therapy (PDT). Compared with PTT and PDT, the novel techniques of sonodynamic therapy (SDT) and photoacoustic therapy (PAT) exhibit amplified ROS generation and precise photoacoustic-shockwaves to enhance anticancer effect when BP receives ultrasound or NIR irradiation. Based on the prospective phototherapy, BP with irradiation can cause a “double-kill” to tumor cells, involving tumor-structure damage induced by heat, ROS, and shockwaves and a subsequent anticancer immune response induced by in situ vaccines construction in tumor site, which is referred to as photoimmunotherapy (PIT). In conclusion, BP shows promise in natural antitumor biological activity, biological imaging, drug delivery, PTT/PDT/SDT/PAT/PIT, nanovaccines, nanoadjuvants, and combination immunotherapy regimens.