Disruption of Her2-Induced PD-L1 Inhibits Tumor Cell Immune Evasion in Patient-Derived Gastric Cancer Organoids

Drivers of centrosome abnormalities: Senescence progression and tumor immune escape

Centrosome abnormalities are a distinguishing feature of cancer and play a role in the aging process. Cancer cells may evade the immune system by activating immune checkpoints, altering their surrounding microenvironment, abnormalities in antigen presentation and recognition, and metabolic reprogramming to inhibit T-cell activity, allowing cancer cells to survive and spread within the host. When the centrosomes are abnormally shaped or numbered, mitotic errors can occur, cellular senescence occurs, cell death occurs, genomic instability occurs, and aneuploidy forms, resulting in diseases such as cancer. The present study is exploring the strategy of research progress in which centrosome abnormalities contribute to the aging process in various different ways as well as fuel immune escape from cancer cells, providing a new direction for cancer immunotherapy.

Preclinical study of inetetamab combined with atezolizumab to synergistically inhibit HER2 and PD-L1 in the treatment of ovarian cancer

Epithelial ovarian cancer (EOC) is the deadliest gynecological malignancy. Precision treatments are crucial for improving patient survival. This research explored the potential anti-tumor effects of combining inetetamab and atezolizumab for HER2+ EOC patients. The expressions of human epidermal growth factor receptor 2 (HER2) and programmed cell death ligand 1 (PD-L1) in EOC cells were evaluated. EOC cell-derived subcutaneous and peritoneal dissemination mouse models were used to evaluate the anti-tumor effects of inetetamab, with or without atezolizumab. The correlations between the expressions of HER2 and PD-L1 as well as the infiltration of T cells in tumors from patients and mice were analyzed by immunohistochemistry. Inetetamab suppressed the growth of HER2+ tumors in mouse models. HER2 overexpression increased PD-L1 levels in EOC cells. The expression level of HER2 is positively related to that of PD-L1 in the tumors of EOC patients as well as the infiltration of both CD4+ and CD8+ T cells. The combination of inetetamab and atezolizumab impeded the growth of HER2+ EOC tumors in vivo and induced a long-term anti-tumor effect with the elevated infiltration of CD103+CD8+ cells. These findings suggest that the combination of inetetamab and atezolizumab could be a promising precision treatment strategy for HER2+ EOC patients.

Novel research model for in vitro immunotherapy: co-culturing tumor organoids with peripheral blood mononuclear cells

Tumor organoids have emerged as powerful tools for in vitro cancer research due to their ability to retain the structural and genetic characteristics of tumors. Nevertheless, the absence of a complete tumor microenvironment (TME) limits the broader application of organoid models in immunological studies. Given the critical role of immune cells in tumor initiation and progression, the co-culture model of organoids and peripheral blood mononuclear cells (PBMCs) may provide an effective platform for simulating the interactions between immune and tumor cells in vitro. This model stands as a robust instrument for dissecting the TME, elucidating the molecular interactions, and exploring the therapeutic applications of chimeric antigen receptor (CAR)-engineered lymphocytes, as well as other cancer treatment modalities. This review systematically evaluates the advantages and disadvantages of the co-culture model, identifies its technical bottlenecks, and proposes corresponding optimization strategies. By summarizing the latest research advancements in this co-culture model, our goal is to provide valuable insights for further model optimization and clinical application, thereby promoting immunological research and bridging the gap between experimental outcomes and clinical practice.

Applications and evolution of 3D cancer-immune cell models

Understanding the highly complex tumor-immune landscape is an important goal for developing novel immune therapies for solid cancers. To this end, 3D cancer-immune models have emerged as patient-relevant in vitro tools for modeling the tumor-immune landscape and the cellular interactions within it. In this review, we provide an overview of the components and applications of 3D cancer-immune models and discuss their evolution from 2015 to 2023. Specifically, we observe trends in primary cell-sourced, T cell-based complex models used for therapy evaluation and biological discovery. Finally, we describe the challenges of implementing 3D cancer-immune models and the opportunities for maximizing their potential for deciphering the complex tumor-immune microenvironment and identifying novel, clinically relevant drug targets.

Mimicking and analyzing the tumor microenvironment

The tumor microenvironment (TME) is increasingly appreciated to play a decisive role in cancer development and response to therapy in all solid tumors. Hypoxia, acidosis, high interstitial pressure, nutrient-poor conditions, and high cellular heterogeneity of the TME arise from interactions between cancer cells and their environment. These properties, in turn, play key roles in the aggressiveness and therapy resistance of the disease, through complex reciprocal interactions between the cancer cell genotype and phenotype, and the physicochemical and cellular environment. Understanding this complexity requires the combination of sophisticated cancer models and high-resolution analysis tools. Models must allow both control and analysis of cellular and acellular TME properties, and analyses must be able to capture the complexity at high depth and spatial resolution. Here, we review the advantages and limitations of key models and methods in order to guide further TME research and outline future challenges.

Unveiling the functional roles of patient-derived tumour organoids in assessing the tumour microenvironment and immunotherapy

Recent studies have established the pivotal roles of patient-derived tumour organoids (PDTOs), innovative three-dimensional (3D) culture systems, in various biological and medical applications. PDTOs, as promising tools, have been established and extensively used for drug screening, prediction of immune response and assessment of immunotherapeutic effectiveness in various cancer types, including glioma, ovarian cancer and so on. The overarching goal is to facilitate the translation of new therapeutic modalities to guide personalised immunotherapy. Notably, there has been a recent surge of interest in the co-culture of PDTOs with immune cells to investigate the dynamic interactions between tumour cells and immune microenvironment. A comprehensive and in-depth investigation is necessary to enhance our understanding of PDTOs as promising testing platforms for cancer immunotherapy. This review mainly focuses on the latest updates on the applications and challenges of PDTO-based methods in anti-cancer immune responses. We strive to provide a comprehensive understanding of the potential and prospects of PDTO-based technologies as next-generation strategies for advancing immunotherapy approaches.

Application of tumor organoids simulating the tumor microenvironment in basic and clinical research of tumor immunotherapy

Immunotherapy has led to groundbreaking advances in anti-tumor treatment, yet significant clinical challenges remain such as the low proportion of beneficiaries and the lack of effective platforms for predicting therapeutic response. Organoid technology provides a novel solution to these issues. Organoids are three-dimensional tissue cultures derived from adult stem cells or pluripotent stem cells that closely replicate the structural and biological characteristics of native organs, demonstrating particularly strong potential in modeling the tumor microenvironment (TME). Tumor organoids can simulate TME effectively by retaining endogenous matrix components, including various immune cells, or by adding immune cells, cancer-associated fibroblasts, and other components. This provides a novel platform for predicting immunotherapy outcomes, evaluating adoptive cell therapies, and selecting personalized treatment options for patients. Summarizing strategies for constructing tumor organoids that simulate the microenvironment and understanding their advancements in immunotherapy research and clinical application can provide new insights for the development of tumor immunotherapy.

Interpretation of the past, present, and future of organoid technology: an updated bibliometric analysis from 2009 to 2024

Organoid technology has been developed rapidly in the past decade, which involves the exploration of the mechanism of development, regeneration and various diseases, and intersects among multiple disciplines. Thousands of literature on 3D-culture or organoids have been published in the research areas of cell biology tissue engineering, nanoscience, oncology and so on, resulting in it being challenging for researchers to timely summarize these studies. Bibliometric statistics is a helpful way to help researchers clarify the above issues efficiently and manage the whole landscape systematically. In our study, all original articles on organoids were included in the Web of Science database from January 2009 to May 2024, and related information was collected and analyzed using Excel software, "bibliometrix" packages of the R software, VOSviewer and CiteSpace. As results, a total of 6222 papers were included to classify the status quo of the organoids and predict future research areas. Our findings highlight a growing trend in publications related to organoids, with the United States and Netherlands leading in this field. The University of California System, Harvard University, Utrecht University and Utrecht University Medical Center have emerged as pivotal contributors and the key authors in the field include Clevers, H, Beekman, JM and Spence JR. Our results also revealed that the research hotspots and trends of organoids mainly focused on clinical treatment, drug screening, and the application of materials and technologies such as "hydrogel" and "microfluidic technology" in organoids. Next, we had an in-depth interpretation of the development process of organoid research area, including the emergence of technology, the translation from bench to bedsides, the profiles of the most widely studied types of organoids, the application of materials and technologies, and the emerging organoid-immune co-cultures trends. Furthermore, we also discussed the pitfalls, challenges and prospects of organoid technology. In conclusion, this study provides readers straightforward and convenient access to the organoid research field.

HER-2 positive gastric cancer: Current targeted treatments

Gastric cancer (GC) is highly metastatic and characterized by HER2 amplification. Aberrant HER2 expression drives metastasis, therapy resistance, and tumor recurrence. HER2 amplification contributes to drug resistance by upregulating DNA repair enzymes and drug afflux proteins, reducing drug efficacy. HER2 modulates transcription factors critical for cancer stem cell properties, further impacting drug resistance. HER2 activity is influenced by HER-family ligands, promoting oncogenic signaling. These features point to HER2 as a targetable driver in GC. This review outlines recent advances in HER2-mediated mechanisms and their upstream and downstream signaling pathways in GC. Additionally, it discusses preclinical research investigation that comprehends trastuzumab-sensitizing phytochemicals, chemotherapeutics, and nanoparticles as adjunct therapies. These developments hold promise for improving outcomes and enhancing the management of HER2-positive GC.

Gastric cancer patient-derived organoids model for the therapeutic drug screening

BACKGROUND

Gastric cancer (GC) is a highly heterogeneous disease featuring many various histological and molecular subtypes. Therefore, it is imperative to have well-characterized in vitro models for personalized treatment development. Gastric cancer patient-derived organoids (PDOs), re-capitulating in vivo conditions, exhibit high clinical efficacy in predicting drug sensitivity to facilitate the development of cancer precision medicine.

METHODS

PDOs were established from surgically resected GC tumor tissues. Histological and molecular characterization of PDOs and primary tissues were performed via IHC and sequencing analysis. We also conducted drug sensitivity tests using PDO cultures with five chemotherapeutic drugs and twenty-two targeted drugs.

RESULTS

We have successfully constructed a PDOs biobank that included EBV+, intestinal/CIN, diffuse/GS, mixed and Her2+ GC subtypes, and these PDOs captured the pathological and genetic characteristics of corresponding tumors and exhibited different sensitivities to the tested agents. In a clinical case study, we performed an additional drug sensitivity test for a patient who reached an advanced progressive stage after surgery. We discovered that the combination of napabucasin and COTI-2 exhibited a stronger synergistic effect than either drug alone.

CONCLUSION

PDOs maintained the histological and genetic characteristics of original cancer tissues. PDOs biobank opens up new perspectives for studying cancer cell biology and personalized medicine as a preclinical study platform.

Xenograft and organoid models in developing precision medicine for gastric cancer (Review)

Gastric cancer (GC), a highly heterogeneous disease, has diverse histological and molecular subtypes. For precision medicine, well‑characterized models encompassing the full spectrum of subtypes are necessary. Patient‑derived tumor xenografts and organoids serve as important preclinical models in GC research. The main advantage of these models is the retention of phenotypic and genotypic heterogeneity present in parental tumor tissues. Utilizing diverse sequencing techniques and preclinical models for GC research facilitates accuracy in predicting personalized clinical responses to anti‑cancer treatments. The present review summarizes the latest advances of these two preclinical models in GC treatment and drug response assessment.

Cancer organoids: A platform in basic and translational research

An accumulation of previous work has established organoids as good preclinical models of human tumors, facilitating translation from basic research to clinical practice. They are changing the paradigm of preclinical cancer research because they can recapitulate the heterogeneity and pathophysiology of human cancers and more closely approximate the complex tissue environment and structure found in clinical tumors than in vitro cell lines and animal models. However, the potential applications of cancer organoids remain to be comprehensively summarized. In the review, we firstly describe what is currently known about cancer organoid culture and then discuss in depth the basic mechanisms, including tumorigenesis and tumor metastasis, and describe recent advances in patient-derived tumor organoids (PDOs) for drug screening and immunological studies. Finally, the present challenges faced by organoid technology in clinical practice and its prospects are discussed. This review highlights that organoids may offer a novel therapeutic strategy for cancer research.

Organoid co-culture models of the tumor microenvironment promote precision medicine

In recent years, the three-dimensional (3D) culture system has emerged as a promising preclinical model for tumor research owing to its ability to replicate the tissue structure and molecular characteristics of solid tumors in vivo. This system offers several advantages, including high throughput, efficiency, and retention of tumor heterogeneity. Traditional Matrigel-submerged organoid cultures primarily support the long-term proliferation of epithelial cells. One solution for the exploration of the tumor microenvironment is a reconstitution approach involving the introduction of exogenous cell types, either in dual, triple or even multiple combinations. Another solution is a holistic approach including patient-derived tumor fragments, air-liquid interface, suspension 3D culture, and microfluidic tumor-on-chip models. Organoid co-culture models have also gained popularity for studying the tumor microenvironment, evaluating tumor immunotherapy, identifying predictive biomarkers, screening for effective drugs, and modeling infections. By leveraging these 3D culture systems, it is hoped to advance the clinical application of therapeutic approaches and improve patient outcomes.

Anti-HER2 biparatopic antibody KJ015 has near-native structure, functional balanced high affinity, and synergistic efficacy with anti-PD-1 treatment in vivo

Currently approved human epidermal growth factor receptor 2 (HER2)-targeted antibody therapies are largely derived from trastuzumab, including trastuzumab-chemotherapy combinations, fixed-dose trastuzumab-pertuzumab combinations, and trastuzumab antibody-drug conjugates. To expand the options, bispecific antibodies, which may better utilize the benefits of combination therapy, are being developed. Among them, biparatopic antibodies (bpAbs) have shown improved efficacy compared to monoclonal antibody (mAb) combinations in HER2-positive patients. BpAbs bind two independent epitopes on the same antigen, which allows fine-tuning of mechanisms of action, including enhancement of on-target specificity and induction of strong antigen clustering due to the unique binding mode. To fully utilize the potential of bpAbs for anti-HER2 drug development, it is crucial to consider formats that offer stability and high-yield production, along with a functional balance between the two epitopes. In this study, we rationally designed a bpAb, KJ015, that shares a common light chain with two Fab arms and exhibits functionally balanced high affinity for two HER2 non-overlapping epitopes. KJ015 demonstrated high-expression titers over 7 g/L and stable physicochemical properties at elevated concentrations, facilitating subcutaneous administration with hyaluronidase. Moreover, KJ015 maintained comparable antibody-dependent cytotoxicity, phagocytosis, and complement-dependent cytotoxicity with trastuzumab plus pertuzumab. It exhibited enhanced synergy when administered subcutaneously with hyaluronidase and anti-PD-1 mAb in a mouse tumor model, suggesting promising clinical prospects for this combination.

Prognostic value of PD‑L1 expression and CD68 macrophages in tumor nest of patients with primary gastric cancer

The programmed death receptor 1/programmed death receptor ligand 1 axis (PD-1/PD-L1) is involved in tumor immune escape and is a potential prognostic biomarker and anti-tumor immunotherapy target in patients with gastric cancer (GC). However, the results of studies obtained in recent years have been inconsistent. The present study aimed to determine the possible predictive significance of PD-L1 in conjunction with three proteins linked with PD-L1 regulation in patients with primary GC. In the present study, the PD-L1, human epidermal growth factor receptor 2 (HER2), cluster of differentiation (CD)133 and microphage-associated CD68 expression levels were identified by multiplexed immunohistochemistry and assessed by automated pathological analysis system in 93 GC tumors and neighboring normal tissues arrayed on the same tissue microarray. All four proteins were statistically analyzed in relation to the clinicopathological characteristics. The expression levels of HER2, CD133 and CD68 were considerably higher in cancer tissues compared with neighboring normal tissues (P<0.05), however, the reverse trend was detected for PD-L1 expression (P=0.0577), particularly in tumor nest (TN; P<0.05). There was no significant correlation between the HER2 and CD133 expression levels and clinicopathological factors. However, significant relationships were found between PD-L1 expression and the TNM stage, pathological differentiation and survival status of patients (P<0.05). Moreover, survival time was prolonged in individuals with elevated PD-L1 expression in TN and GC tissues, but no significant correlation was identified (P=0.0881). The CD68 expression level in tumor stroma, but not in TN, was significantly correlated with poor pathological differentiation in patients with GC (P<0.05). However, PD-L1+CD68+ macrophages were strongly related to lower tumor size (diameter <5 cm), early TNM stage (stage I+II), good pathological differentiation and overall survival in TN (P<0.05). In conclusion, PD-L1+CD68+ macrophage infiltration in TN might be a potential indicator of prognosis in patients with primary GC and merits further investigation.

Promising preclinical patient-derived organoid (PDO) and xenograft (PDX) models in upper gastrointestinal cancers: progress and challenges

Gastrointestinal (GI) cancers (gastric cancer, oesophageal cancer, liver cancer, colorectal cancer, etc.) are the most common cancers with the highest morbidity and mortality in the world. The therapy for most GI cancers is difficult and is associated with a poor prognosis. In China, upper GI cancers, mainly gastric cancer (GC) and oesophageal cancer (EC), are very common due to Chinese people's characteristics, and more than half of patients are diagnosed with distant metastatic or locally advanced disease. Compared to other solid cancers, such as lung cancer and breast cancer, personalized therapies, especially targeted therapy and immunotherapy, in GC and EC are relatively lacking, leading to poor prognosis. For a long time, most studies were carried out by using in vitro cancer cell lines or in vivo cell line-derived xenograft models, which are unable to reproduce the characteristics of tumours derived from patients, leading to the possible misguidance of subsequent clinical validation. The patient-derived models represented by patient-derived organoid (PDO) and xenograft (PDX) models, known for their high preservation of patient tumour features, have emerged as a very popular platform that has been widely used in numerous studies, especially in the research and development of antitumour drugs and personalized medicine. Herein, based on some of the available published literature, we review the research and application status of PDO and PDX models in GC and EC, as well as detail their future challenges and prospects, to promote their use in basic and translational studies or personalized therapy.

Multicenter phase I dose escalation and expansion study of pyrotinib in combination with camrelizumab and chemotherapy as first-line treatment for HER2-positive advanced gastric and gastroesophageal junction adenocarcinoma

Background

Pembrolizumab plus trastuzumab and chemotherapy showed remarkable efficacy as first-line therapy for advanced HER2-positive gastric cancer. Pyrotinib is an irreversible pan-HER inhibitor. This single-arm, open-label phase 1 dose-escalation (1a) and expansion (1b) study investigated camrelizumab, an anti-PD-1 antibody, plus pyrotinib and chemotherapy as first-line treatment for advanced HER2-positive gastric and gastroesophageal junction (G/GEJ) adenocarcinoma.

Methods

Between June 2020 and June 2022, 41 patients with previously untreated HER2-positive locally advanced unresectable or metastatic G/GEJ adenocarcinoma were enrolled. In phase 1a, patients underwent a 3 + 3 escalating dose design, receiving oral pyrotinib (240 mg, 320 mg, or 400 mg daily), intravenous camrelizumab (200 mg), and CapeOX (oxaliplatin 130 mg/m2 on day 1 and capecitabine 1000 mg/m2 twice daily for two weeks) every 3 weeks until progression, intolerable toxicity or consent withdrawal. The recommended phase 2 dose (RP2D) of pyrotinib was determined and used in the phase 1b. The primary endpoints were the safety, maximum tolerated dose (MTD), RP2D, and confirmed objective response rate (ORR). This trial was registered with chictr.org, number ChiCTR2000029717.

Findings

Among 41 patients, 10 were in phase 1a (3 at 240 mg, 3 at 400 mg, and 4 at 320 mg due to one patient withdrawing consent), and 31 were in phase 1b. In phase 1a, the MTD of pyrotinib was 320 mg daily due to dose-limiting toxicities (diarrhea [n = 3] and vomiting [n = 1]) observed at 400 mg. Based on all available data, the RP2D of pyrotinib was set at 320 mg. Among 41 patients, 20 patients (48.8%) developed grade ≥3 treatment-emergent adverse events (TEAEs), and four patients (9.8%) had any grade serious adverse events. No deaths occurred due to TEAEs. Among 27 patients who received the RP2D of pyrotinib and had a post-baseline tumor assessment, two patients (7.4%) achieved a confirmed complete response, and 19 patients (70.4%) achieved a confirmed partial response, resulting in a confirmed ORR of 77.8% (95% CI: 57.7-91.4).

Interpretation

Pyrotinib plus camrelizumab and chemotherapy showed promising efficacy in the first-line treatment of advanced HER2-positive G/GEJ cancer. The safety profile was consistent with known toxicities of the agents, and no new or unexpected safety signals were identified.

Funding

This study was funded by the Beijing Xisike Clinical Oncology Research Foundation (Y-HR2019-0377).

Biomarkers and experimental models for cancer immunology investigation

The rapid advancement of tumor immunotherapies poses challenges for the tools used in cancer immunology research, highlighting the need for highly effective biomarkers and reproducible experimental models. Current immunotherapy biomarkers encompass surface protein markers such as PD-L1, genetic features such as microsatellite instability, tumor-infiltrating lymphocytes, and biomarkers in liquid biopsy such as circulating tumor DNAs. Experimental models, ranging from 3D in vitro cultures (spheroids, submerged models, air-liquid interface models, organ-on-a-chips) to advanced 3D bioprinting techniques, have emerged as valuable platforms for cancer immunology investigations and immunotherapy biomarker research. By preserving native immune components or coculturing with exogenous immune cells, these models replicate the tumor microenvironment in vitro. Animal models like syngeneic models, genetically engineered models, and patient-derived xenografts provide opportunities to study in vivo tumor-immune interactions. Humanized animal models further enable the simulation of the human-specific tumor microenvironment. Here, we provide a comprehensive overview of the advantages, limitations, and prospects of different biomarkers and experimental models, specifically focusing on the role of biomarkers in predicting immunotherapy outcomes and the ability of experimental models to replicate the tumor microenvironment. By integrating cutting-edge biomarkers and experimental models, this review serves as a valuable resource for accessing the forefront of cancer immunology investigation.

Immunotherapeutic strategy in the management of gastric cancer: molecular profiles, current practice, and ongoing trials

Gastric cancer (GC) is the one of the most commonly solid cancer worldwide. Although under the aggressive treatment, the poor clinical outcomes of patients with GCs have not been improved. Current studies emphasized that targeting therapies or immune response-based therapeutic strategy may be a potential approach to improve the clinical outcomes. Moreover, accumulative evidence has reported the increasing expression of PD-L1 expression in GC cells and highlighted its role in the tumor progression. Currently, great development has been established in the immune checkpoint inhibitors (ICIs) and further changed the clinical practice of GC treatment and prognosis. In addition, the combination therapies with targeting therapy or traditional therapies are expected to push the development of immunotherapies. In our present review, we predominantly focus on the biomarkers and molecular profiles for immunotherapies in GCs and highlight the role and administration of ICIs-based immunotherapeutic strategies against the GCs.

Molecular Recognition Study toward the Mitochondrial Electron Transport Chain Inhibitor Mubritinib and Human Serum Albumin

The ability to bind plasma proteins helps in comprehending relevant aspects related to the pharmacological properties of many drugs. Despite the vital role of the drug mubritinib (MUB) in the prophylaxis of various diseases, its interaction with carrier proteins still needs to be clarified. The present work focuses on the interaction between MUB and Human serum albumin (HSA), investigated by employing multispectroscopic, biochemical, and molecular docking approaches. The results reveal that MUB has quenched HSA intrinsic fluorescence (following a static mechanism) by attaching very close (r = 6.76 Å) and with moderate affinity (Kb ≈ 104 M-1) to the protein site I (mainly by H-bonds, hydrophobic and Van der Waals forces). On one side, the HSA-MUB interaction has been accompanied by a slight disturbance in the HSA chemical environment (around the Trp residue) and protein secondary structure modifications. On another side, MUB competitively inhibits HSA esterase-like activity, which is very similar to other Tyrosine kinase inhibitors, and evidence that protein functional alterations have been triggered by MUB interaction. In summary, all of the presented observations can shed light on diverse pharmacological factors associated with drug administration.

Organoids: approaches and utility in cancer research

ABSTRACT

Organoids are three-dimensional cellular structures with self-organizing and self-differentiation capacities. They faithfully recapitulate structures and functions of in vivo organs as represented by functionality and microstructural definitions. Heterogeneity in in vitro disease modeling is one of the main reasons for anti-cancer therapy failures. Establishing a powerful model to represent tumor heterogeneity is crucial for elucidating tumor biology and developing effective therapeutic strategies. Tumor organoids can retain the original tumor heterogeneity and are commonly used to mimic the cancer microenvironment when co-cultured with fibroblasts and immune cells; therefore, considerable effort has been made recently to promote the use of this new technology from basic research to clinical studies in tumors. In combination with gene editing technology and microfluidic chip systems, engineered tumor organoids show promising abilities to recapitulate tumorigenesis and metastasis. In many studies, the responses of tumor organoids to various drugs have shown a positive correlation with patient responses. Owing to these consistent responses and personalized characteristics with patient data, tumor organoids show excellent potential for preclinical research. Here, we summarize the properties of different tumor models and review their current state and progress in tumor organoids. We further discuss the substantial challenges and prospects in the rapidly developing tumor organoid field.

Cancer organoid co-culture model system: Novel approach to guide precision medicine

Three-dimensional cancer organoids derived from self-organizing cancer stems are ex vivo miniatures of tumors that faithfully recapitulate their structure, distinctive cancer features, and genetic signatures. As novel tools, current cancer organoids have been well established and rapidly applied in drug testing, genome editing, and transplantation, with the ultimate aim of entering clinical practice for guiding personalized therapy. However, given that the lack of a tumor microenvironment, including immune cells and fibrous cells, is a major limitation of this emerging methodology, co-culture models inspire high hope for further application of this technology in cancer research. Co-culture of cancer organoids and immune cells or fibroblasts is available to investigate the tumor microenvironment, molecular interactions, and chimeric antigen receptor-engineered lymphocytes in cancer treatment. In light of the recent progress in cancer organoid co-culture models, it is only possible to recognize the advantages and drawbacks of this novel model to exploit its full potential. In this review, we summarize the recent advances in the application of cancer organoids and co-culture models and how they could be improved in the future to benefit cancer research, especially precision medicine.

Patient-derived xenografts or organoids in the discovery of traditional and self-assembled drug for tumor immunotherapy

In addition to the rapid development of immune checkpoint inhibitors, there has also been a surge in the development of self-assembly immunotherapy drugs. Based on the immune target, traditional tumor immunotherapy drugs are classified into five categories, namely immune checkpoint inhibitors, direct immune modulators, adoptive cell therapy, oncolytic viruses, and cancer vaccines. Additionally, the emergence of self-assembled drugs with improved precision and environmental sensitivity offers a promising innovation approach to tumor immunotherapy. Despite rapid advances in tumor immunotherapy drug development, all candidate drugs require preclinical evaluation for safety and efficacy, and conventional evaluations are primarily conducted using two-dimensional cell lines and animal models, an approach that may be unsuitable for immunotherapy drugs. The patient-derived xenograft and organoids models, however, maintain the heterogeneity and immunity of the pathological tumor heterogeneity.

Incorporating Immunotherapy in the Management of Gastric Cancer: Molecular and Clinical Implications

Simple Summary

Gastric cancer is one of the most common malignant tumours worldwide, with the fifth and third highest morbidity and mortality, respectively, of all cancers. Survival is limited, as most of the patients are diagnosed at an advanced stage, and are not suitable for surgery with a curative intent. Chemotherapy has only modestly improved patients’ outcomes and is mainly given with a palliative intent. Immunotherapy has improved overall survival of patients with gastric cancer, and has thus become a new standard of care in clinic. In this review we discuss the strong molecular rationale for the administration of immunotherapy in this disease and analyse the clinical data supporting its use.

Abstract

Gastric cancer has a median survival of 11 months, and this poor prognosis has not improved over the last 30 years. Recent pre-clinical data suggest that there is high tumour-related neoantigen expression in gastric cancer cells, suggesting that a clinical strategy that enhances the host’s immune system against cancer cells may be a successful approach to improve clinical outcomes. Additionally, there has been an increasing amount of translational evidence highlighting the relevance of PD-L1 expression in gastric cancer cells, indicating that PD-1/PD-L1 inhibitors may be useful. Several molecular subgroups of gastric cancer have been identified to respond with excellent outcomes to immunotherapy, including microsatellite instable tumours, tumours bearing a high tumour mutational burden, and tumours related to a chronic EBV infection. In gastric cancer, immunotherapy has produced durable responses in chemo-refractory patients; however, most recently there has been a lot of enthusiasm as several large-scale clinical trials highlight the improved survival noted from the incorporation of immunotherapy in the first line setting for advanced gastric cancer. Our review aims to discuss current pre-clinical and clinical data supporting the innovative role of immunotherapy in gastric cancer.

Targeting HDAC6 to Overcome Autophagy-Promoted Anti-Cancer Drug Resistance

Histone deacetylases (HDACs) regulate gene expression through the epigenetic modification of chromatin structure. HDAC6, unlike many other HDACs, is present in the cytoplasm. Its deacetylates non-histone proteins and plays diverse roles in cancer cell initiation, proliferation, autophagy, and anti-cancer drug resistance. The development of HDAC6-specific inhibitors has been relatively successful. Mechanisms of HDAC6-promoted anti-cancer drug resistance, cancer cell proliferation, and autophagy are discussed. The relationship between autophagy and anti-cancer drug resistance is discussed. The effects of combination therapy, which includes HDAC6 inhibitors, on the sensitivity of cancer cells to chemotherapeutics and immune checkpoint blockade are presented. A summary of clinical trials involving HDAC6-specific inhibitors is also presented. This review presents HDAC6 as a valuable target for developing anti-cancer drugs.

Case Report: Complete Remission of a Patient With Metastatic Gastric Cancer Treated With Nivolumab Combined With Chemotherapy After Palliative Surgery

Metastatic advanced gastric cancer, for which treatment strategies are extremely limited, has a poor prognosis. Complete remission is rare. Patients usually lose the opportunity of therapeutic surgery because the lesions cannot be completely removed, although it can greatly prolong their survival time. Palliative surgery usually suggests bad outcomes. In recent years, the immune checkpoint inhibitor (ICI) nivolumab has shown significant efficacy in the treatment of advanced gastric cancer. However, its applicable conditions and optimal withdrawal time remain controversial owing to its low response rate and high incidence of immune-related adverse events. Herein, we introduce a 66-year-old male patient with advanced gastric cancer with multiple liver metastases who underwent laparoscopic total gastrectomy for acute gastric bleeding. The patient received eight cycles of S-1 plus oxaliplatin (SOX) and switched to eight cycles of SOX plus nivolumab combined regimen in a stable state, later achieving complete remission. There was no recurrence for 32 months after the surgery. This is the first reported case of gastric cancer with multiple liver metastases with long-term complete remission with nivolumab treatment after palliative surgery. The potential mechanism of complete remission was discussed through clinical, genomic, and immune characteristics. The patient had a history of psoriasis and was positive for programmed death ligand 1 (PD-L1), and the interaction of TP53 mutation and HER-2 (-) gene may be associated with complete remission.

Improvement of the anticancer efficacy of PD-1/PD-L1 blockade via combination therapy and PD-L1 regulation

Immune checkpoint molecules are promising anticancer targets, among which therapeutic antibodies targeting the PD-1/PD-L1 pathway have been widely applied to cancer treatment in clinical practice and have great potential. However, this treatment is greatly limited by its low response rates in certain cancers, lack of known biomarkers, immune-related toxicity, innate and acquired drug resistance, etc. Overcoming these limitations would significantly expand the anticancer applications of PD-1/PD-L1 blockade and improve the response rate and survival time of cancer patients. In the present review, we first illustrate the biological mechanisms of the PD-1/PD-L1 immune checkpoints and their role in the healthy immune system as well as in the tumor microenvironment (TME). The PD-1/PD-L1 pathway inhibits the anticancer effect of T cells in the TME, which in turn regulates the expression levels of PD-1 and PD-L1 through multiple mechanisms. Several strategies have been proposed to solve the limitations of anti-PD-1/PD-L1 treatment, including combination therapy with other standard treatments, such as chemotherapy, radiotherapy, targeted therapy, anti-angiogenic therapy, other immunotherapies and even diet control. Downregulation of PD-L1 expression in the TME via pharmacological or gene regulation methods improves the efficacy of anti-PD-1/PD-L1 treatment. Surprisingly, recent preclinical studies have shown that upregulation of PD-L1 in the TME also improves the response and efficacy of immune checkpoint blockade. Immunotherapy is a promising anticancer strategy that provides novel insight into clinical applications. This review aims to guide the development of more effective and less toxic anti-PD-1/PD-L1 immunotherapies.

Gastric cancer and genomics: review of literature

Gastric cancer (GC) is a major health concern in many countries. GC is a heterogeneous disease stratified by histopathological differences. However, these variations are not used to determine GC management. Next-generation sequencing (NGS) technologies have become widely used, and cancer genomic analysis has recently revealed the relationships between various malignant tumors and genomic information. In 2014, studies using whole-exome sequencing (WES) and whole-genome sequencing (WGS) for GC revealed the entire structure of GC genomics. Genomics with NGS has been used to identify new therapeutic targets for GC. Moreover, personalized medicine to provide specific therapy for targets based on multiplex gene panel testing of tumor tissues has become of clinical use. Recently, immune checkpoint inhibitors (ICIs) have been used for GC treatment; however, their response rates are limited. To predict the anti-tumor effects of ICIs for GC and to select patients suitable for ICI treatment, genomics also provides informative data not only of tumors but also of tumor microenvironments, such as tumor-infiltrating lymphocytes. In therapeutic strategies for unresectable or recurrent malignant tumors, the target is not only the primary lesion but also metastatic lesions, and metastatic lesions are often resistant to chemotherapy. Unlike colorectal carcinoma, there is a heterogeneous status of genetic variants between the primary and metastatic lesions in GC. Liquid biopsy analysis is also helpful for predicting the genomic status of both primary and metastatic lesions. Genomics has become an indispensable tool for GC treatment and is expected to be further developed in the future.