Cisplatin-induced immune modulation in ovarian cancer mouse models with distinct inflammation profiles

Plasmacytoid dendritic cells at the forefront of anti-cancer immunity: rewiring strategies for tumor microenvironment remodeling

Plasmacytoid dendritic cells (pDCs) are multifaceted immune cells executing various innate immunological functions. Their first line of defence consists in type I interferons (I-IFN) production upon nucleic acids sensing through endosomal Toll-like receptor (TLR) 7- and 9-dependent signalling pathways. Type I IFNs are a class of proinflammatory cytokines that have context-dependent functions on cancer immunosurveillance and immunoediting. In the last few years, different studies have reported that pDCs are also able to sense cytosolic DNA through cGAS-STING (stimulator of interferon genes) pathway eliciting a potent I-IFN production independently of TLR7/9. Human pDCs are also endowed with direct effector functions via the upregulation of TRAIL and production of granzyme B, the latter modulated by cytokines abundant in cancer tissues. pDCs have been detected in a wide variety of human malignant neoplasms, including virus-associated cancers, recruited by chemotactic stimuli. Although the role of pDCs in cancer immune surveillance is still uncompletely understood, their spontaneous activation has been rarely documented; moreover, their presence in the tumor microenvironment (TME) has been associated with a tolerogenic phenotype induced by immunosuppressive cytokines or oncometabolites. Currently tested treatment options can lead to pDCs activation and disruption of the immunosuppressive TME, providing a relevant clinical benefit. On the contrary, the antibody-drug conjugates targeting BDCA-2 on immunosuppressive tumor-associated pDCs (TA-pDCs) could be proposed as novel immunomodulatory therapies to achieve disease control in patients with advance stage hematologic malignancies or solid tumors. This Review integrate recent evidence on the biology of pDCs and their pharmacological modulation, suggesting their relevant role at the forefront of cancer immunity.

Temperature-sensitive nanogels combined with polyphosphate and cisplatin for the enhancement of tumor artery embolization by coagulation activation

Transcatheter arterial chemoembolization (TACE) is the first-line therapy for hepatocellular carcinoma (HCC). However, the exacerbated hypoxia microenvironment induces tumor relapse and metastasis post-TACE. Here, temperature-sensitive block polymer complexed with polyphosphate-cisplatin (Pt-P@PND) was prepared for the enhancement of tumor artery embolization by coagulation activation. After supra-selective infusion into the tumor vessels, Pt-P@PND nanogels performed efficient embolization of tumor arteries by sol-gel transition at body temperature. Meanwhile, coagulation cascade was evoked to form blood clots in the peripheral arteries inaccessible to the nanogels by released PolyP. The blood clots-filled hydrogel networks composed of gel and clots showed a denser structure and higher modulus, thereby achieving long-term embolization of all levels of tumor arteries. Pt-P@PND nanogels efficiently inhibited tumor growth and reduced the expression of HIF-1α, VEGF, CD31, and MMP-9 on VX2 tumor-bearing rabbit model. The released Nitro-Pt stimulated the immunogenic cell death of tumor cells, thus enhancing the antitumor immune response to suppress tumor relapse and metastasis post-TACE. It is hoped that Pt-P@PND nanogels can be developed as a promising embolic agent with procoagulant activity for enhancing the antitumor immune response through a combination of embolism, coagulation, and chemotherapy. STATEMENT OF SIGNIFICANCE: Clinical embolic agents, such as Lipiodol and polyvinyl alcohol (PVA) microspheres, are limited by their rapid elimination or larger size, thus lead to incomplete embolization of trans-catheter arterial chemoembolization (TACE). Herein, temperature-sensitive Pt-P@PND nanogels were developed to achieve long-term embolization of all levels of tumor arteries by gel/clot generation. The released Nitro-Pt induced immunogenic cell death in tumor cells, which improved the antitumor immune microenvironment by the maturation of DCs and lymphocytic infiltration. Pt-P@PND nanogels successfully inhibited tumor growth and activated an antitumor immune response to curb the recurrence and metastasis of residual tumor cells both in VX2 tumor-bearing rabbit model and 4T1 tumor-bearing mouse model. These findings suggested that Pt-P@PND could be developed as an ideal embolic agent for clinical TACE treatment.

Stimulator of Interferon Genes Protein (STING) Expression in Cancer Cells: A Tissue Microarray Study Evaluating More than 18,000 Tumors from 139 Different Tumor Entities

Stimulator of interferon genes protein (STING) activates the immune response in inflammatory cells. STING expression in cancer cells is less well characterized, but STING agonists are currently being evaluated as anticancer drugs. A tissue microarray containing 18,001 samples from 139 different tumor types was analyzed for STING by immunohistochemistry. STING-positive tumor cells were found in 130 (93.5%) of 139 tumor entities. The highest STING positivity rates occurred in squamous cell carcinomas (up to 96%); malignant mesothelioma (88.5%-95.7%); adenocarcinoma of the pancreas (94.9%), lung (90.3%), cervix (90.0%), colorectum (75.2%), and gallbladder (68.8%); and serous high-grade ovarian cancer (86.0%). High STING expression was linked to adverse phenotypes in breast cancer, clear cell renal cell carcinoma, colorectal adenocarcinoma, hepatocellular carcinoma, and papillary carcinoma of the thyroid (p < 0.05). In pTa urothelial carcinomas, STING expression was associated with low-grade carcinoma (p = 0.0002). Across all tumors, STING expression paralleled PD-L1 positivity of tumor and inflammatory cells (p < 0.0001 each) but was unrelated to the density of CD8+ lymphocytes. STING expression is variable across tumor types and may be related to aggressive tumor phenotype and PD-L1 positivity. The lack of relationship with tumor-infiltrating CD8+ lymphocytes argues against a significant IFN production by STING positive tumor cells.

Novel frontiers in urogenital cancers: from molecular bases to preclinical models to tailor personalized treatments in ovarian and prostate cancer patients

Over the last few decades, the incidence of urogenital cancers has exhibited diverse trends influenced by screening programs and geographical variations. Among women, there has been a consistent or even increased occurrence of endometrial and ovarian cancers; conversely, prostate cancer remains one of the most diagnosed malignancies, with a rise in reported cases, partly due to enhanced and improved screening efforts.Simultaneously, the landscape of cancer therapeutics has undergone a remarkable evolution, encompassing the introduction of targeted therapies and significant advancements in traditional chemotherapy. Modern targeted treatments aim to selectively address the molecular aberrations driving cancer, minimizing adverse effects on normal cells. However, traditional chemotherapy retains its crucial role, offering a broad-spectrum approach that, despite its wider range of side effects, remains indispensable in the treatment of various cancers, often working synergistically with targeted therapies to enhance overall efficacy.For urogenital cancers, especially ovarian and prostate cancers, DNA damage response inhibitors, such as PARP inhibitors, have emerged as promising therapeutic avenues. In BRCA-mutated ovarian cancer, PARP inhibitors like olaparib and niraparib have demonstrated efficacy, leading to their approval for specific indications. Similarly, patients with DNA damage response mutations have shown sensitivity to these agents in prostate cancer, heralding a new frontier in disease management. Furthermore, the progression of ovarian and prostate cancer is intricately linked to hormonal regulation. Ovarian cancer development has also been associated with prolonged exposure to estrogen, while testosterone and its metabolite dihydrotestosterone, can fuel the growth of prostate cancer cells. Thus, understanding the interplay between hormones, DNA damage and repair mechanisms can hold promise for exploring novel targeted therapies for ovarian and prostate tumors.In addition, it is of primary importance the use of preclinical models that mirror as close as possible the biological and genetic features of patients' tumors in order to effectively translate novel therapeutic findings "from the bench to the bedside".In summary, the complex landscape of urogenital cancers underscores the need for innovative approaches. Targeted therapy tailored to DNA repair mechanisms and hormone regulation might offer promising avenues for improving the management and outcomes for patients affected by ovarian and prostate cancers.

Deubiquitinating enzymes: potential regulators of the tumor microenvironment and implications for immune evasion

Ubiquitination and deubiquitination are important forms of posttranslational modification that govern protein homeostasis. Deubiquitinating enzymes (DUBs), a protein superfamily consisting of more than 100 members, deconjugate ubiquitin chains from client proteins to regulate cellular homeostasis. However, the dysregulation of DUBs is reportedly associated with several diseases, including cancer. The tumor microenvironment (TME) is a highly complex entity comprising diverse noncancerous cells (e.g., immune cells and stromal cells) and the extracellular matrix (ECM). Since TME heterogeneity is closely related to tumorigenesis and immune evasion, targeting TME components has recently been considered an attractive therapeutic strategy for restoring antitumor immunity. Emerging studies have revealed the involvement of DUBs in immune modulation within the TME, including the regulation of immune checkpoints and immunocyte infiltration and function, which renders DUBs promising for potent cancer immunotherapy. Nevertheless, the roles of DUBs in the crosstalk between tumors and their surrounding components have not been comprehensively reviewed. In this review, we discuss the involvement of DUBs in the dynamic interplay between tumors, immune cells, and stromal cells and illustrate how dysregulated DUBs facilitate immune evasion and promote tumor progression. We also summarize potential small molecules that target DUBs to alleviate immunosuppression and suppress tumorigenesis. Finally, we discuss the prospects and challenges regarding the targeting of DUBs in cancer immunotherapeutics and several urgent problems that warrant further investigation.

Second messenger 2'3'-cyclic GMP-AMP (2'3'-cGAMP): the cell autonomous and non-autonomous roles in cancer progression

Cytosolic double-stranded DNA (dsDNA) is frequently accumulated in cancer cells due to chromosomal instability or exogenous stimulation. Cyclic GMP-AMP synthase (cGAS) acts as a cytosolic DNA sensor, which is activated upon binding to dsDNA to synthesize the crucial second messenger 2'3'-cyclic GMP-AMP (2'3'-cGAMP) that in turn triggers stimulator of interferon genes (STING) signaling. The canonical role of cGAS-cGAMP-STING pathway is essential for innate immunity and viral defense. Recent emerging evidence indicates that 2'3'-cGAMP plays an important role in cancer progression via cell autonomous and non-autonomous mechanisms. Beyond its role as an intracellular messenger to activate STING signaling in tumor cells, 2'3'-cGAMP also serves as an immunotransmitter produced by cancer cells to modulate the functions of non-tumor cells especially immune cells in the tumor microenvironment by activating STING signaling. In this review, we summarize the synthesis, transmission, and degradation of 2'3'-cGAMP as well as the dual functions of 2'3'-cGAMP in a STING-dependent manner. Additionally, we discuss the potential therapeutic strategies that harness the cGAMP-mediated antitumor response for cancer therapy.

The double life of a chemotherapy drug: Immunomodulatory functions of gemcitabine in cancer

Although the development of immunotherapies has been revolutionary in the treatment of several cancers, many cancer types remain unresponsive to immune-based treatment and are largely managed by chemotherapy drugs. However, chemotherapeutics are not infallible and are frequently rendered ineffective as resistance develops from prolonged exposure. Recent investigations have indicated that some chemotherapy drugs have additional functions beyond their normative cytotoxic capacity and are in fact immune-modifying agents. Of the pharmaceuticals with identified immune-editing properties, gemcitabine is well-studied and of interest to clinicians and scientists alike. Gemcitabine is a chemotherapy drug approved for the treatment of multiple cancers, including breast, lung, pancreatic, and ovarian. Because of its broad applications, relatively low toxicity profile, and history as a favorable combinatory partner, there is promise in the recharacterization of gemcitabine in the context of the immune system. Such efforts may allow the identification of suitable immunotherapeutic combinations, wherein gemcitabine can be used as a priming agent to improve immunotherapy efficacy in traditionally insensitive cancers. This review looks to highlight documented immunomodulatory abilities of one of the most well-known chemotherapy agents, gemcitabine, relating to its influence on cells and proteins of the immune system.

Lovastatin/SN38 co-loaded liposomes amplified ICB therapeutic effect via remodeling the immunologically-cold colon tumor and synergized stimulation of cGAS-STING pathway

Current immune checkpoint blockade (ICB) immunotherapeutics have revolutionized cancer treatment. However, many cancers especially the "immunologically cold" tumors, do not respond to ICB, prompting the search for additional strategies to achieve durable responses. The cGAS-STING pathway, as an essential immune response pathway, has been demonstrated for a potent target to sensitize ICB immunotherapy. However, the low efficiency of conventional STING agonists limits their clinical application. Recent studies have shown that DNA topoisomerase I (TOPI) inhibitor chemodrug SN38 can activate the cGAS-STING pathway and induce an immune response through DNA damage, while the traditional statins medication lovastatin was found to inhibit DNA damage repair, which may in turn upregulate the damaged DNA level. Herein, we have developed a liposomal carrier co-loaded with SN38 and lovastatin (SL@Lip), which can be accumulated in tumors and efficiently released SN38 and lovastatin, addressing the problem of weak solubility of these two drugs. Importantly, lovastatin can increase DNA damage and enhance the activation of cGAS-STING pathway, coordinating with SN38 chemotherapy and exhibiting the enhanced combinational immunotherapy of PD-1 antibody by remodeling the tumor microenvironment in mouse colorectal cancer of both subcutaneous and orthotopic xenograft models. Overall, this study demonstrates that lovastatin-assisted cGAS-STING stimulation mediated by liposomal delivery system significantly strengthened both chemotherapy and immunotherapy of colorectal cancer, providing a clinically translational strategy for combinational ICB therapy in the "immunologically cold" tumors.

Discovery of a triphenylamine-based ligand that targets mitochondrial DNA G-quadruplexes and activates the cGAS-STING immunomodulatory pathway

Stabilization of G-quadruplex (G4) structures in mitochondria leads to the damage of mitochondrial DNA (mtDNA), making mtDNA G4s a promising target in the field of cancer therapy in recent years. Damaged mtDNA released into the cytosol can stimulate cytosolic DNA-sensing pathways, and cGAS-STING pathway is a typical one with potent immunostimulatory effects. A few small molecule ligands of mtDNA G4s are identified with antitumor efficacy, but little is known about their results and mechanisms on immunomodulation. In this study, we engineered a series of triphenylamine-based analogues targeting mtDNA G4s, and A6 was determined as the most promising compound. Cellular studies indicated that A6 caused severe mtDNA damage. Then, damaged mtDNA stimulated cGAS-STING pathway, resulting in the following cytokine production of tumor cells and the maturation of DCs. In vivo experiments certified that A6 exerted suppressive influences on tumor growth and metastasis in 4T1 cell-bearing mice by the regulation of TME, including the remodeling of macrophages and the activation of T cells. To our knowledge, it is the first time to report a ligand targeting mtDNA G4s to activate the cGAS-STING immunomodulatory pathway, providing a novel strategy for the future development of mtDNA G4-based antitumor agents.

cGAS-STING, an important signaling pathway in diseases and their therapy

Since cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway was discovered in 2013, great progress has been made to elucidate the origin, function, and regulating mechanism of cGAS-STING signaling pathway in the past decade. Meanwhile, the triggering and transduction mechanisms have been continuously illuminated. cGAS-STING plays a key role in human diseases, particularly DNA-triggered inflammatory diseases, making it a potentially effective therapeutic target for inflammation-related diseases. Here, we aim to summarize the ancient origin of the cGAS-STING defense mechanism, as well as the triggers, transduction, and regulating mechanisms of the cGAS-STING. We will also focus on the important roles of cGAS-STING signal under pathological conditions, such as infections, cancers, autoimmune diseases, neurological diseases, and visceral inflammations, and review the progress in drug development targeting cGAS-STING signaling pathway. The main directions and potential obstacles in the regulating mechanism research and therapeutic drug development of the cGAS-STING signaling pathway for inflammatory diseases and cancers will be discussed. These research advancements expand our understanding of cGAS-STING, provide a theoretical basis for further exploration of the roles of cGAS-STING in diseases, and open up new strategies for targeting cGAS-STING as a promising therapeutic intervention in multiple diseases.

A Stem-like Patient-Derived Ovarian Cancer Model of Platinum Resistance Reveals Dissociation of Stemness and Resistance

To understand chemoresistance in the context of cancer stem cells (CSC), a cisplatin resistance model was developed using a high-grade serous ovarian cancer patient-derived, cisplatin-sensitive sample, PDX4. As a molecular subtype-specific stem-like cell line, PDX4 was selected for its representative features, including its histopathological and BRCA2 mutation status, and exposed to cisplatin in vitro. In the cisplatin-resistant cells, transcriptomics were carried out, and cell morphology, protein expression, and functional status were characterized. Additionally, potential signaling pathways involved in cisplatin resistance were explored. Our findings reveal the presence of distinct molecular signatures and phenotypic changes in cisplatin-resistant PDX4 compared to their sensitive counterparts. Surprisingly, we observed that chemoresistance was not inherently linked with increased stemness. In fact, although resistant cells expressed a combination of EMT and stemness markers, functional assays revealed that they were less proliferative, migratory, and clonogenic-features indicative of an underlying complex mechanism for cell survival. Furthermore, DNA damage tolerance and cellular stress management pathways were enriched. This novel, syngeneic model provides a valuable platform for investigating the underlying mechanisms of cisplatin resistance in a clinically relevant context, contributing to the development of targeted therapies tailored to combat resistance in stem-like ovarian cancer.

cGAS-STING pathway mediates activation of dendritic cell sensing of immunogenic tumors

Type I interferons (IFN-I) play pivotal roles in tumor therapy for three decades, underscoring the critical importance of maintaining the integrity of the IFN-1 signaling pathway in radiotherapy, chemotherapy, targeted therapy, and immunotherapy. However, the specific mechanism by which IFN-I contributes to these therapies, particularly in terms of activating dendritic cells (DCs), remains unclear. Based on recent studies, aberrant DNA in the cytoplasm activates the cyclic GMP-AMP synthase (cGAS)- stimulator of interferon genes (STING) signaling pathway, which in turn produces IFN-I, which is essential for antiviral and anticancer immunity. Notably, STING can also enhance anticancer immunity by promoting autophagy, inflammation, and glycolysis in an IFN-I-independent manner. These research advancements contribute to our comprehension of the distinctions between IFN-I drugs and STING agonists in the context of oncology therapy and shed light on the challenges involved in developing STING agonist drugs. Thus, we aimed to summarize the novel mechanisms underlying cGAS-STING-IFN-I signal activation in DC-mediated antigen presentation and its role in the cancer immune cycle in this review.

Targeting Tryptophan Catabolism in Ovarian Cancer to Attenuate Macrophage Infiltration and PD-L1 Expression

High-grade serous carcinoma (HGSC) of the fallopian tube, ovary, and peritoneum is the most common type of ovarian cancer and is predicted to be immunogenic because the presence of tumor-infiltrating lymphocytes conveys a better prognosis. However, the efficacy of immunotherapies has been limited because of the immune-suppressed tumor microenvironment (TME). Tumor metabolism and immune-suppressive metabolites directly affect immune cell function through the depletion of nutrients and activation of immune-suppressive transcriptional programs. Tryptophan (TRP) catabolism is a contributor to HGSC disease progression. Two structurally distinct rate-limiting TRP catabolizing enzymes, indoleamine 2,3-dioxygenase 1 (IDO1) and tryptophan 2,3-dioxygenase 2 (TDO2), evolved separately to catabolize TRP. IDO1/TDO2 are aberrantly expressed in carcinomas and metabolize TRP into the immune-suppressive metabolite kynurenine (KYN), which can engage the aryl hydrocarbon receptor to drive immunosuppressive transcriptional programs. To date, IDO inhibitors tested in clinical trials have had limited efficacy, but those inhibitors did not target TDO2, and we find that HGSC cell lines and clinical outcomes are more dependent on TDO2 than IDO1. To identify inflammatory HGSC cancers with poor prognosis, we stratified patient ascites samples by IL6 status, which correlates with poor prognosis. Metabolomics revealed that IL6-high patient samples had enriched KYN. TDO2 knockdown significantly inhibited HGSC growth and TRP catabolism. The orally available dual IDO1/TDO2 inhibitor, AT-0174, significantly inhibited tumor progression, reduced tumor-associated macrophages, and reduced expression of immune-suppressive proteins on immune and tumor cells. These studies demonstrate the importance of TDO2 and the therapeutic potential of AT-0174 to overcome an immune-suppressed TME.

SIGNIFICANCE

Developing strategies to improve response to chemotherapy is essential to extending disease-free intervals for patients with HGSC of the fallopian tube, ovary, and peritoneum. In this article, we demonstrate that targeting TRP catabolism, particularly with dual inhibition of TDO2 and IDO1, attenuates the immune-suppressive microenvironment and, when combined with chemotherapy, extends survival compared with chemotherapy alone.

Camrelizumab plus gemcitabine and oxaliplatin for relapsed or refractory classical Hodgkin lymphoma: a phase II trial

BACKGROUND

Classical Hodgkin lymphoma (cHL) is a highly curable disease, while novel therapy is needed for refractory or relapsed (R/R) patients. This phase II trial aimed to evaluate the role of camrelizumab plus gemcitabine and oxaliplatin (GEMOX) in R/R cHL patients.

METHODS

Transplant-eligible patients with R/R cHL were enrolled and received two 14-day cycles of camrelizumab 200 mg intravenously (IV) and two 28-day cycles of camrelizumab 200 mg IV, gemcitabine 1000 mg/m2 IV, and oxaliplatin 100 mg/m2 IV on days 1 and 15. Patients with partial response (PR) or stable disease received an additional cycle of combination therapy. Those who achieved complete response (CR) or PR proceeded to autologous stem cell transplantation (ASCT). The primary endpoint was the CR rate at the end of protocol therapy before ASCT.

RESULTS

Forty-two patients were enrolled. At the end of protocol therapy, the objective response rate and CR rate were 94.9% (37/39) and 69.2% (27/39) in the evaluable set, and 88.1% (37/42) and 64.3% (27/42) in the full analysis set, respectively. Twenty-nine patients (69.0%) proceeded to ASCT, and 4 of 5 patients with PR achieved CR after ASCT. After a median follow-up of 20.7 months, the 12-month progression-free survival rate was 96.6% and the 12-month overall survival rate was 100%. Grade 3 or higher treatment emergent adverse events occurred in 28.6% of patients (12/42), mainly hematological toxicity.

CONCLUSIONS

Camrelizumab combined with GEMOX constitutes an effective salvage therapy for R/R cHL, proving to be relatively well-tolerated and facilitating ASCT in most patients, thus promoting sustained remission.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04239170. Registered on January 1, 2020.

Immunomodulatory effects and improved outcomes with cisplatin- versus carboplatin-based chemotherapy plus atezolizumab in urothelial cancer

In metastatic urothelial cancer (mUC), cisplatin versus carboplatin leads to durable disease control in a subset of patients. The IMvigor130 trial reveals more favorable effects with atezolizumab combined with gemcitabine and cisplatin (GemCis) versus gemcitabine and carboplatin (GemCarbo). This study investigates the immunomodulatory effects of cisplatin as a potential explanation for these observations. Our findings indicate that improved outcomes with GemCis versus GemCarbo are primarily observed in patients with pretreatment tumors exhibiting features of restrained adaptive immunity. In addition, GemCis versus GemCarbo ± atezolizumab induces transcriptional changes in circulating immune cells, including upregulation of antigen presentation and T cell activation programs. In vitro experiments demonstrate that cisplatin, compared with carboplatin, exerts direct immunomodulatory effects on cancer cells, promoting dendritic cell activation and antigen-specific T cell killing. These results underscore the key role of immune modulation in cisplatin's efficacy in mUC and highlight the importance of specific chemotherapy backbones in immunotherapy combination regimens.

The Putative Effects of Neoadjuvant Chemotherapy on the Immune System of Advanced Epithelial Ovarian Carcinoma

The epithelial ovarian carcinoma (EOC) is one of leading causes of cancer-related mortality in females. For some patients, complete resection cannot be achieved, thus neoadjuvant chemotherapy (NACT) following interval debulking surgery (IDS) could be an alternative choice. In general-held belief, cytotoxic chemotherapy is assumed to be immunosuppressive, because of its toxicity to dividing cells in the bone marrow and peripheral lymphoid tissues. However, increasing evidence highlighted that the anticancer activity of chemotherapy may also be related to its ability to act as an immune modulator. NACT not only changed the morphology of cancer cells, but also changed the transcriptomic and genomic profile of EOC, induced proliferation of cancer stem-like cells, gene mutation, and tumor-related adaptive immune response. This review will provide a comprehensive overview of recent studies evaluating the impact of NACT on cancer cells and immune system of advanced EOC and their relationship to clinical outcome. This information could help us understand the change of immune system during NACT, which might provide new strategies in future investigation of immuno-therapy for maintenance treatment of EOC.

cGAS-STING and PD1/PDL-1 pathway in breast cancer: a window to new therapies

Breast cancer is a complex malignancy with diverse molecular and cellular subtypes and clinical outcomes. Despite advances in treatment, breast cancer remains a significant health challenge. However, recent advances in cancer immunotherapy have shown promising results in the treatment of breast cancer, particularly the use of inhibitors that target the immune checkpoint PD1/PDL1. Also, the cGAS-STING pathway, an important part of the innate immune response, has been considered as a major potential therapeutic target for breast cancer. In this narrative review, we provide an overview of the cGAS-STING and PD1/PDL-1 pathway in breast cancer, including their role in tumor development, progression, and response to treatment. We also discuss potential future directions for research.

Molecular map of cGAS-STING pathway-related genes in bladder cancer: the perspective toward immune microenvironment and prognosis

BACKGROUND

The cGAS-STING pathway emerges as a pivotal innate immune pathway with the potential to profoundly influence all facets of tumor initiation and progression. The prognostic significance and immunological role of cGAS-STING pathway-related genes (CRGs) in individuals diagnosed with bladder cancer (BLCA) have not yet been fully elucidated.

METHODS

Performed unsupervised cluster analysis to identify distinct clusters. Utilizing LASSO and multivariate Cox regression analysis to construct a prognostic risk model. The IMvigor210, GSE13507 and GSE78220 cohorts were utilized to explore the potential value of risk score in immune therapy response and survival prediction.

RESULTS

A risk model was developed utilizing four CRGs in order to forecast the overall survival (OS) of BLCA patients. The risk score to be a standalone risk factor, which was further corroborated by the external validation set obtained from the GEO database (GSE13507). We established an integrated nomogram that combined risk scoring and clinical information, exhibiting commendable clinical practicality in predicting the overall survival period of BLCA patients. It is noteworthy that risk score could differentiate tumor microenvironments among different risk groups and individuals who were more responsive to immunotherapy in IMvigor210 and GSE13507 cohorts. In vitro experiments, we noted an up-regulation of IRF3 and IKBKB upon the activation of the cGAS-STING pathway. Conversely, the activation of the cGAS-STING pathway resulted in a down-regulation of POLR3G and CTNNB1.

CONCLUSIONS

CRG risk model shows promise as a potential stratification approach for bladder cancer patients.

Combining cisplatin and a STING agonist into one molecule for metalloimmunotherapy of cancer

Mounting evidence suggests that strategies combining DNA-damaging agents and stimulator of interferon genes (STING) agonists are promising cancer therapeutic regimens because they can amplify STING activation and remodel the immunosuppressive tumor microenvironment. However, a single molecular entity comprising both agents has not yet been developed. Herein, we designed two PtIV-MSA-2 conjugates (I and II) containing the DNA-damaging chemotherapeutic drug cisplatin and the innate immune-activating STING agonist MSA-2; these conjugates showed great potential as multispecific small-molecule drugs against pancreatic cancer. Mechanistic studies revealed that conjugate I upregulated the expression of transcripts associated with innate immunity and metabolism in cancer cells, significantly differing from cisplatin and MSA-2. An analysis of the tumor microenvironment demonstrated that conjugate I could enhance the infiltration of natural killer (NK) cells into tumors and promote the activation of T cells, NK cells and dendritic cells in tumor tissues. These findings indicated that conjugate I, which was created by incorporating a Pt chemotherapeutic drug and STING agonist into one molecule, is a promising and potent anticancer drug candidate, opening new avenues for small-molecule-based cancer metalloimmunotherapy.

PD-1 inhibitor combined with Docetaxel exerts synergistic anti-prostate cancer effect in mice by down-regulating the expression of PI3K/AKT/NFKB-P65/PD-L1 signaling pathway

BACKGROUND

Docetaxel is a yew compound antitumor agent with accurate antitumor efficacy, but its application is limited due to the high and serious adverse effects, and finding effective combination therapy options is a viable strategy. Immune checkpoint inhibitors have become hotspots in enhancing anti-tumor immunity by blocking immune checkpoint signaling pathways, but their response rate to monotherapy use is not high and the efficacy is minimal.

OBJECTIVE

To explore the anti-tumor effects and mechanisms of the combination of PD-1 inhibitors and Docetaxel through in vivo experiments and develop a feasible combination treatment for the therapy of prostate cancer.

METHODS

Tumor-bearing mice were subcutaneously injected with 0.1 ml RM-1 cells. Treatment were taken when the tumor growed up to 3 mm, after which the tumor and spleen were removed to test the antitumor effect with Flow cytometric (FACS) analysis, Immunohistochemistry, Western Blot.

RESULTS

In this experiment, we found that PD-1 inhibitors combined with Docetaxel had a synergistic effect on mouse prostate cancer, inhibited the growth of prostate cancer, improved survival and reduced adverse reactions, increased spleen and tumor infiltrative CD4+ and CD8+ T cells, especially in group combination with low-dose Docetaxel, and were related to the PI3K/AKT/NFKB-P65/PD-L1 signaling pathway.

CONCLUSION

Our study confirms that PD-1 inhibitors in combination with Docetaxel are a viable combination strategy and provide a safe and effective combination option for the clinical treatment of prostate cancer.

Inhibition of ACLY overcomes cancer immunotherapy resistance via polyunsaturated fatty acids peroxidation and cGAS-STING activation

Adenosine 5'-triphosphate citrate lyase (ACLY) is a cytosolic enzyme that converts citrate into acetyl-coenzyme A for fatty acid and cholesterol biosynthesis. ACLY is up-regulated or activated in many cancers, and targeting ACLY by inhibitors holds promise as potential cancer therapy. However, the role of ACLY in cancer immunity regulation remains poorly understood. Here, we show that ACLY inhibition up-regulates PD-L1 immune checkpoint expression in cancer cells and induces T cell dysfunction to drive immunosuppression and compromise its antitumor effect in immunocompetent mice. Mechanistically, ACLY inhibition causes polyunsaturated fatty acid (PUFA) peroxidation and mitochondrial damage, which triggers mitochondrial DNA leakage to activate the cGAS-STING innate immune pathway. Pharmacological and genetic inhibition of ACLY overcomes cancer resistance to anti-PD-L1 therapy in a cGAS-dependent manner. Furthermore, dietary PUFA supplementation mirrors the enhanced efficacy of PD-L1 blockade by ACLY inhibition. These findings reveal an immunomodulatory role of ACLY and provide combinatorial strategies to overcome immunotherapy resistance in tumors.

Polyadenosine diphosphate-ribose polymerase inhibitors: advances, implications, and challenges in tumor radiotherapy sensitization

Polyadenosine diphosphate-ribose polymerase (PARP) is a key modifying enzyme in cells, which participates in single-strand break repair and indirectly affects double-strand break repair. PARP inhibitors have shown great potential in oncotherapy by exploiting DNA damage repair pathways, and several small molecule PARP inhibitors have been approved by the U.S. Food and Drug Administration for treating various tumor types. PARP inhibitors not only have significant antitumor effects but also have some synergistic effects when combined with radiotherapy; therefore they have potential as radiation sensitizers. Here, we reviewed the advances and implications of PARP inhibitors in tumor radiotherapy sensitization. First, we summarized the multiple functions of PARP and the mechanisms by which its inhibitors exert antitumor effects. Next, we discuss the immunomodulatory effects of PARP and its inhibitors in tumors. Then, we described the theoretical basis of using PARP inhibitors in combination with radiotherapy and outlined their importance in oncological radiotherapy. Finally, we reviewed the current challenges in this field and elaborated on the future applications of PARP inhibitors as radiation sensitizers. A comprehensive understanding of the mechanism, optimal dosing, long-term safety, and identification of responsive biomarkers remain key challenges to integrating PARP inhibition into the radiotherapy management of cancer patients. Therefore, extensive research in these areas would facilitate the development of precision radiotherapy using PARP inhibitors to improve patient outcomes.

Eicosapentaenoic acid enhances the sensitivity of osteosarcoma to cisplatin by inducing ferroptosis through the DNA-PKcs/AKT/NRF2 pathway and reducing PD-L1 expression to attenuate immune evasion

Acquired drug resistance poses a significant challenge in osteosarcoma therapy. Therefore, it is necessary for us to discover and develop an alternative anti-cancer strategy. Previous studies have shown that eicosapentaenoic acid (EPA) significantly increases chemosensitivity in cancer cells. In this study, we discovered that EPA enhances the sensitivity of osteosarcoma to cisplatin (DDP). Interestingly, in addition to inhibiting growth and inducing apoptosis, EPA also enhances DDP-induced ferroptosis. Western blot analysis confirmed that EPA treatment significantly decreases the expression of DNA-dependent protein kinase catalytic subunit (DNA-PKcs), p-AKT, nuclear factor erythroid 2-related factor 2 (NRF2), and glutathione peroxidase 4 (GPX4) in cells. Knockdown of DNA-PKcs by siRNA further enhances the level of ferroptosis induced by EPA. Importantly, EPA can reverse the high expression level of programmed death ligand 1 (PD-L1) induced by DDP. ELISA and western blotting analysis revealed that EPA treatment decreases the levels of IL-6 and p-STAT3, which are increased by DDP treatment. Furthermore, a co-immunoprecipitation (co-IP) assay confirmed the interaction between DNA-PKcs and PD-L1, and knockdown of DNA-PKcs further reduces the expression of PD-L1. This data provides the first evidence that EPA suppresses the DNA-PKcs/AKT/NRF2/GPX4 pathway to enhance ferroptosis, and inhibits IL-6/STAT3 and DNA-PKcs to decrease PD-L1 expression, thereby sensitizing osteosarcoma to DDP. The combination of EPA and DDP presents an encouraging and promising anti-tumor strategy.

Effect of neoadjuvant chemotherapy on the immune microenvironment of gynaecological tumours

Purpose: To assess the impact of neoadjuvant chemotherapy (NACT) on the tumor immune microenvironment (TIME) in gynaecological tumors, with a focus on understanding the potential for enhanced combination therapies.Methods: We systematically queried the PubMed, Embase, and Cochrane databases, encompassing reviews, clinical trials, and case studies, to undertake a thorough analysis of the impact of NACT on the TIME of gynaecological tumors.Results: NACT induces diverse immune microenvironment changes in gynaecological tumors. In cervical cancer, NACT boosts immune-promoting cells, enhancing tumor clearance. Ovarian cancer studies yield variable outcomes, influenced by patient-specific factors and treatment regimens. Limited research exists on NACT's impact on endometrial cancer's immune microenvironment, warranting further exploration. In summary, NACT-induced immune microenvironment changes display variability. Clinical trials highlight personalized immunotherapy's positive impact on gynaecological tumor prognosis, suggesting potential avenues for future cancer treatments. However, rigorous investigation is needed to determine the exact efficacy and safety of combining NACT with immunotherapy.Conclusion: This review provides a solid foundation for the development of late-stage immunotherapy and highlights the importance of therapeutic strategies targeting immune cells in TIME in anti-tumor therapy.

cGAS-STING Pathway Activation and Systemic Anti-Tumor Immunity Induction via Photodynamic Nanoparticles with Potent Toxic Platinum DNA Intercalator Against Uveal Melanoma

The cGAS-STING pathway, as a vital innate immune signaling pathway, has attracted considerable attention in tumor immunotherapy research. However, STING agonists are generally incapable of targeting tumors, thus limiting their clinical applications. Here, a photodynamic polymer (P1) is designed to electrostatically couple with 56MESS-a cationic platinum (II) agent-to form NPPDT -56MESS. The accumulation of NPPDT -56MESS in the tumors increases the efficacy and decreases the systemic toxicity of the drugs. Moreover, NPPDT -56MESS generates reactive oxygen species (ROS) under the excitation with an 808 nm laser, which then results in the disintegration of NPPDT -56MESS. Indeed, the ROS and 56MESS act synergistically to damage DNA and mitochondria, leading to a surge of cytoplasmic double-stranded DNA (dsDNA). This way, the cGAS-STING pathway is activated to induce anti-tumor immune responses and ultimately enhance anti-cancer activity. Additionally, the administration of NPPDT -56MESS to mice induces an immune memory effect, thus improving the survival rate of mice. Collectively, these findings indicate that NPPDT -56MESS functions as a chemotherapeutic agent and cGAS-STING pathway agonist, representing a combination chemotherapy and immunotherapy strategy that provides novel modalities for the treatment of uveal melanoma.

STING in tumors: a focus on non-innate immune pathways

Cyclic GMP-AMP synthase (cGAS) and downstream stimulator of interferon genes (STING) are involved in mediating innate immunity by promoting the release of interferon and other inflammatory factors. Mitochondrial DNA (mtDNA) with a double-stranded structure has greater efficiency and sensitivity in being detected by DNA sensors and thus has an important role in the activation of the cGAS-STING pathway. Many previous findings suggest that the cGAS-STING pathway-mediated innate immune regulation is the most important aspect affecting tumor survival, not only in its anti-tumor role but also in shaping the immunosuppressive tumor microenvironment (TME) through a variety of pathways. However, recent studies have shown that STING regulation of non-immune pathways is equally profound and also involved in tumor cell progression. In this paper, we will focus on the non-innate immune system pathways, in which the cGAS-STING pathway also plays an important role in cancer.

Prognostic Significance of Programmed Cell Death Ligand 1 Expression in High-Grade Serous Ovarian Carcinoma: A Systematic Review and Meta-Analysis

(1) Background: High-grade serous ovarian carcinoma (HGSOC) is an aggressive subtype of ovarian cancer. Recent advances have introduced prognostic markers and targeted therapies. Programmed cell death ligand 1 (PD-L1) has emerged as a potential biomarker for HGSOC, with implications for prognosis and targeted therapy eligibility; (2) Methods: A literature search was conducted on major databases, and extracted data were categorized and pooled. Subgroup analysis was performed for studies with high heterogeneity. (3) Results: Data from 18 eligible studies were categorized and pooled based on PD-L1 scoring methods, survival analysis types, and endpoints. The result showed an association between high PD-L1 expression and a favorable prognosis in progression-free survival (HR = 0.53, 95% CI = 0.35-0.78, p = 0.0015). Subgroup analyses showed similar associations in subgroups of neoadjuvant chemotherapy patients (HR = 0.6, 95% CI = 0.4-0.88, p = 0.009) and European studies (HR = 0.59, 95% CI = 0.42-0.82, p = 0.0017). In addition, subgroup analyses using data from studies using FDA-approved PD-L1 antibodies suggested a significant association between favorable prognosis and high PD-L1 expression in a subgroup including high and low stage data in overall survival data (HR = 0.46, 95% CI = 0.3-0.73, p = 0.0009). (4) Conclusions: This meta-analysis revealed a potential association between high PD-L1 expression and favorable prognosis. However, caution is warranted due to several limitations. Validation via large-scale studies, with mRNA analysis, whole tissue sections, and assessments using FDA-approved antibodies is needed.

Targeting the loss of cGAS/STING signaling in cancer

The cGAS/STING pathway provides a key host defense mechanism by detecting the accumulation of cytoplasmic double-stranded DNA (dsDNA) and mediating innate and adaptive immune signaling. In addition to detecting pathogen-derived dsDNA, cGAS senses intrinsic dsDNA, such as those associated with defective cell cycle progression and mitophagy that has leaked from the nucleus or mitochondria, and subsequently evokes host immunity to eliminate pathogenic cells. In cancer cells, dysregulation of DNA repair and cell cycle caused at the DNA replication checkpoint and spindle assembly checkpoint results in aberrant cytoplasmic dsDNA accumulation, stimulating anti-tumor immunity. Therefore, the suppression of cGAS/STING signaling is beneficial for survival and frequently observed in cancer cells as a way to evade detection by the immune system, and is likely to be related to immune checkpoint blockade (ICB) resistance. Indeed, the mechanisms of ICB resistance overlap with those acquired in cancers during immunoediting to evade immune surveillance. This review highlights the current understanding of cGAS/STING suppression in cancer cells and discusses how to establish effective strategies to regenerate effective anti-tumor immunity through reactivation of the cGAS/STING pathway.

Maltol has anti-cancer effects via modulating PD-L1 signaling pathway in B16F10 cells

Introduction: Among skin cancers, melanoma has a high mortality rate. Recent advances in immunotherapy, particularly through immune checkpoint modulation, have improved the clinical treatment of melanoma. Maltol has various bioactivities, including anti-oxidant and anti-inflammatory properties, but the anti-melanoma property of maltol remains underexplored. The aim of this work is to explore the anti-melanoma potential of maltol through regulating immune checkpoints. Methods: The immune checkpoint PD-L1 was analyzed using qPCR, immunoblots, and immunofluorescence. Melanoma sensitivity towards T cells was investigated via cytotoxicity, cell viability, and IL-2 assays employing CTLL-2 cells. Results: Maltol was found to reduce melanin contents, tyrosinase activity, and expression levels of tyrosinase and tyrosinase-related protein 1. Additionally, maltol suppressed the proliferative capacity of B16F10 and induced cell cycle arrest. Maltol increased apoptotic rates by elevating cleaved caspase-3 and PARP. The co-treatment with maltol and cisplatin revealed a synergistic effect on inhibiting growth and promoting apoptosis. Maltol suppressed IFN-γ-induced PD-L1 and cisplatin-upregulated PD-L1 by attenuating STAT1 phosphorylation, thereby enhancing cisplatin's cytotoxicity against B16F10. Maltol augmented sensitivity to CTLL-2 cell-regulated melanoma destruction, leading to an increase in IL-2 production. Discussion: These findings demonstrate that maltol restricts melanoma growth through the downregulation of PD-L1 and elicits T cell-mediated anti-cancer responses, overcoming PD-L1-mediated immunotherapy resistance of cisplatin. Therefore, maltol can be considered as an effective therapeutic agent against melanoma.

Recent trends in STING modulators: Structures, mechanisms, and therapeutic potential

The cyclic GMP-AMP synthase stimulator (cGAS)-stimulator of interferon gene (STING) signaling pathway has an integral role in the host immune response through DNA sensing followed by inducing a robust innate immune defense program. STING has become a promising therapeutic target associated with multiple diseases, including various inflammatory diseases, cancer, and infectious diseases, among others. Thus, modulators of STING are regarded as emerging therapeutic agents. Recent progress has been made in STING research, including recently identified STING-mediated regulatory pathways, the development of a new STING modulator, and the new association of STING with disease. In this review, we focus on recent trends in the development of STING modulators, including structures, mechanisms, and clinical application.

Strategies to synergize PD-1/PD-L1 targeted cancer immunotherapies to enhance antitumor responses in ovarian cancer

Anti-programmed cell death 1/programmed cell death ligand 1 (anti-PD-1/PD-L1) antibodies have developed rapidly but exhibited modest activity in ovarian cancer (OC), achieving a clinical response rate ranging from 5.9% to 19%. Current evidence indicate that the establishment of an integrated cancer-immunity cycle is a prerequisite for anti-PD-1/PD-L1 antibodies. Any impairment in this cycle, including lack of cancer antigens release, impaired antigen-presenting, decreased T cell priming and activation, less T cells that are trafficked or infiltrated in tumor microenvironment (TME), and low tumor recognition and killings, will lead to decreased infiltrated cytotoxic T cells to tumor bed and treatment failure. Therefore, combinatorial strategies aiming to modify cancer-immunity cycle and reprogram tumor immune microenvironment are of great interest. By far, various strategies have been studied to enhance responsiveness to PD-1/PD-L1 inhibitors in OC. Platinum-based chemotherapy increases neoantigens release; poly (ADP-ribose) polymerase (PARP) inhibitors (PARPis) improve the function of antigen-presenting cells and promote the trafficking of T cells into tumors; epigenetic drugs help to complete the immune cycle by affecting multiple steps; immunotherapies like anti-cytotoxic T lymphocyte antigen 4 (CTLA-4) antibodies reactivate T cells, and other treatment strategies like radiotherapy helps to increase the expression of tumor antigens. In this review, we will summarize the preclinical studies by analyzing their contribution in modifying the cancer immunity cycle and remodeling tumor environment, and we will also summarize recent progress in clinical trials and discuss some perspectives to improve these treatment strategies.

Significance of the cGAS-STING Pathway in Health and Disease

The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway plays a significant role in health and disease. In this pathway, cGAS, one of the major cytosolic DNA sensors in mammalian cells, regulates innate immunity and the STING-dependent production of pro-inflammatory cytokines, including type-I interferon. Moreover, the cGAS-STING pathway is integral to other cellular processes, such as cell death, cell senescence, and autophagy. Activation of the cGAS-STING pathway by "self" DNA is also attributed to various infectious diseases and autoimmune or inflammatory conditions. In addition, the cGAS-STING pathway activation functions as a link between innate and adaptive immunity, leading to the inhibition or facilitation of tumorigenesis; therefore, research targeting this pathway can provide novel clues for clinical applications to treat infectious, inflammatory, and autoimmune diseases and even cancer. In this review, we focus on the cGAS-STING pathway and its corresponding cellular and molecular mechanisms in health and disease.

Conventional DNA-Damaging Cancer Therapies and Emerging cGAS-STING Activation: A Review and Perspectives Regarding Immunotherapeutic Potential

Many traditional cancer treatments such as radiation and chemotherapy are known to induce cellular DNA damage as part of their cytotoxic activity. The cGAS-STING signaling axis, a key member of the DNA damage response that acts as a sensor of foreign or aberrant cytosolic DNA, is helping to rationalize the DNA-damaging activity of these treatments and their emerging immunostimulatory capacity. Moreover, cGAS-STING, which is attracting considerable attention for its ability to promote antitumor immune responses, may fundamentally be able to address many of the barriers limiting the success of cancer immunotherapy strategies, including the immunosuppressive tumor microenvironment. Herein, we review the traditional cancer therapies that have been linked with cGAS-STING activation, highlighting their targets with respect to their role and function in the DNA damage response. As part of the review, an emerging "chemoimmunotherapy" concept whereby DNA-damaging agents are used for the indirect activation of STING is discussed as an alternative to the direct molecular agonism strategies that are in development, but have yet to achieve clinical approval. The potential of this approach to address some of the inherent and emerging limitations of cGAS-STING signaling in cancer immunotherapy is also discussed. Ultimately, it is becoming clear that in order to successfully employ the immunotherapeutic potential of the cGAS-STING axis, a balance between its contrasting antitumor and protumor/inflammatory activities will need to be achieved.

Tumor Cells Transmit Drug Resistance via Cisplatin-Induced Extracellular Vesicles

Cisplatin is a first-line clinical agent used for treating solid tumors. Cisplatin damages the DNA of tumor cells and induces the production of high levels of reactive oxygen species to achieve tumor killing. Tumor cells have evolved several ways to tolerate this damage. Extracellular vesicles (EVs) are an important mode of information transfer in tumor cells. EVs can be substantially activated under cisplatin treatment and mediate different responses of tumor cells under cisplatin treatment depending on their different cargoes. However, the mechanism of action of tumor-cell-derived EVs under cisplatin treatment and their potential cargoes are still unclear. This review considers recent advances in cisplatin-induced release of EVs from tumor cells, with the expectation of providing a new understanding of the mechanisms of cisplatin treatment and drug resistance, as well as strategies for the combined use of cisplatin and other drugs.

Lipid-based nanoparticles as drug delivery systems for cancer immunotherapy

Immune checkpoint inhibitors (ICIs) have shown remarkable success in cancer treatment. However, in cancer patients without sufficient antitumor immunity, numerous data indicate that blocking the negative signals elicited by immune checkpoints is ineffective. Drugs that stimulate immune activation-related pathways are emerging as another route for improving immunotherapy. In addition, the development of nanotechnology presents a promising platform for tissue and cell type-specific delivery and improved uptake of immunomodulatory agents, ultimately leading to enhanced cancer immunotherapy and reduced side effects. In this review, we summarize and discuss the latest developments in nanoparticles (NPs) for cancer immuno-oncology therapy with a focus on lipid-based NPs (lipid-NPs), including the characteristics and advantages of various types. Using the agonists targeting stimulation of the interferon genes (STING) transmembrane protein as an exemplar, we review the potential of various lipid-NPs to augment STING agonist therapy. Furthermore, we present recent findings and underlying mechanisms on how STING pathway activation fosters antitumor immunity and regulates the tumor microenvironment and provide a summary of the distinct STING agonists in preclinical studies and clinical trials. Ultimately, we conduct a critical assessment of the obstacles and future directions in the utilization of lipid-NPs to enhance cancer immunotherapy.

Adjuvant physiochemistry and advanced nanotechnology for vaccine development

Vaccines comprising innovative adjuvants are rapidly reaching advanced translational stages, such as the authorized nanotechnology adjuvants in mRNA vaccines against COVID-19 worldwide, offering new strategies to effectively combat diseases threatening human health. Adjuvants are vital ingredients in vaccines, which can augment the degree, extensiveness, and longevity of antigen specific immune response. The advances in the modulation of physicochemical properties of nanoplatforms elevate the capability of adjuvants in initiating the innate immune system and adaptive immunity, offering immense potential for developing vaccines against hard-to-target infectious diseases and cancer. In this review, we provide an essential introduction of the basic principles of prophylactic and therapeutic vaccination, key roles of adjuvants in augmenting and shaping immunity to achieve desired outcomes and effectiveness, and the physiochemical properties and action mechanisms of clinically approved adjuvants for humans. We particularly focus on the preclinical and clinical progress of highly immunogenic emerging nanotechnology adjuvants formulated in vaccines for cancer treatment or infectious disease prevention. We deliberate on how the immune system can sense and respond to the physicochemical cues (e.g., chirality, deformability, solubility, topology, and chemical structures) of nanotechnology adjuvants incorporated in the vaccines. Finally, we propose possible strategies to accelerate the clinical implementation of nanotechnology adjuvanted vaccines, such as in-depth elucidation of nano-immuno interactions, antigen identification and optimization by the deployment of high-dimensional multiomics analysis approaches, encouraging close collaborations among scientists from different scientific disciplines and aggressive exploration of novel nanotechnologies.

Biomaterial-enabled therapeutic modulation of cGAS-STING signaling for enhancing antitumor immunity

cGAS-STING signaling is a central component in the therapeutic action of most existing cancer therapies. The accumulated knowledge of tumor immunoregulatory network in recent years has spurred the development of cGAS-STING agonists for tumor treatment as an effective immunotherapeutic strategy. However, the clinical translation of these agonists is thus far unsatisfactory because of the low immunostimulatory efficacy and unrestricted side effects under clinically relevant conditions. Interestingly, the rational integration of biomaterial technology offers a promising approach to overcome these limitations for more effective and safer cGAS-STING-mediated tumor therapy. Herein, we first outline the cGAS-STING signaling axis and generally discuss its association with tumors. We then symmetrically summarize the recent progress in those biomaterial-based cGAS-STING agonism strategies to generate robust antitumor immunity, categorized by the chemical nature of those cGAS-STING stimulants and carrier substrates. Finally, a perspective is provided to discuss the existing challenges and potential opportunities in cGAS-STING modulation for tumor therapy.

Inhibition of neuroactive ligand-receptor interaction pathway can enhance immunotherapy response in colon cancer: an in silico study

BACKGROUND

The potential mechanism underlying the association between Homologous recombination deficiency (HRD) and immunotherapy in colon cancer has not been investigated.

METHODS

The exon sequencing data and transcriptome data of 456 colon adenocarcinoma (COAD) patients were obtained from the TCGA database. Pathway activity score was calculated by GSVA methods and engaged in further survival analysis. The prognostic value of the candidate pathways was validated in an external GEO cohort and an immunotherapy cohort.

RESULTS

Patients with high HRD were associated with poor prognosis, lower tumor mutation burden and microsatellite instability, higher fraction genome alteration, and less sensitivity to immunotherapy in COAD. And then, the neuroactive ligand-receptor interaction pathway was over-activated in high-HRD tumors and associated with immunosuppression in colon cancer with high HRD. Besides, the pathway was associated with prognosis and immunotherapy response in COAD. Moreover, genes in this pathway such as LTB4R2 can be used as a novel target for therapy development in colon cancer.

CONCLUSION

Our study not only revealed the potential mechanism of HRD and the function of the neuroactive ligand-receptor interaction pathway in colon cancer but also provided new clues for the improvement of immunotherapy response in colon cancer.

Strategies involving STING pathway activation for cancer immunotherapy: Mechanism and agonists

Recent studies have expanded the known functions of cGAS-STING in inflammation to a role in cancer due to its participation in activating immune surveillance. In cancer cells, the cGAS-STING pathway can be activated by cytosolic dsDNA derived from genomic, mitochondrial and exogenous origins. The resulting immune-stimulatory factors from this cascade can either attenuate tumor growth or recruit immune cells for tumor clearance. Furthermore, STING-IRF3-induced type I interferon signaling can enforce tumor antigen presentation on dendritic cells and macrophages and thus cross-prime CD8+ T cells for antitumor immunity. Given the functions of the STING pathway in antitumor immunity, multiple strategies are being developed and tested with the rationale of activating STING in tumor cells or tumor-infiltrating immune cells to elicit immunostimulatory effects, either alone or in combination with a range of established chemotherapeutic and immunotherapeutic regimens. Based on the canonical molecular mechanism of STING activation, numerous strategies for inducing mitochondrial and nuclear dsDNA release have been used to activate the cGAS-STING signaling pathway. Other noncanonical strategies that activate cGAS-STING signaling, including the use of direct STING agonists and STING trafficking facilitation, also show promise in type I interferon release and antitumor immunity priming. Here, we review the key roles of the STING pathway in different steps of the cancer-immunity cycle and characterize the canonical and noncanonical mechanisms of cGAS-STING pathway activation to understand the potential of cGAS-STING agonists for cancer immunotherapy.

Activation of the cGAS-STING pathway by a mitochondrial DNA-targeted emissive rhodium(iii) metallointercalator

The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon (STING) pathway is a key mediator of innate immunity involved in cancer development and treatment. The roles of mitochondrial DNA (mtDNA) in cancer immunotherapy have gradually emerged. Herein, we report a highly emissive rhodium(iii) complex (Rh-Mito) as the mtDNA intercalator. Rh-Mito can specifically bind to mtDNA to cause the cytoplasmic release of mtDNA fragments to activate the cGAS-STING pathway. Moreover, Rh-Mito activates the mitochondrial retrograde signaling by disturbing the key metabolites involved in epigenetic modifications, which alters the nuclear genome methylation landscape to influence the expression of genes related to immune signaling pathways. Finally, we demonstrate that ferritin-encapsulated Rh-Mito elicits potent anticancer activities and evokes intense immune responses in vivo by intravenous injection. Overall, we report for the first time that small molecules targeting mtDNA can activate the cGAS-STING pathway, which gives insights into the development of biomacromolecule-targeted immunotherapeutic agents.

The Mixture of Natural Products SH003 Exerts Anti-Melanoma Effects through the Modulation of PD-L1 in B16F10 Cells

Melanoma is the most invasive and lethal skin cancer. Recently, PD-1/PD-L1 pathway modulation has been applied to cancer therapy due to its remarkable clinical efficacy. SH003, a mixture of natural products derived from Astragalus membranaceus, Angelica gigas, and Trichosanthes kirilowii, and formononetin (FMN), an active constituent of SH003, exhibit anti-cancer and anti-oxidant properties. However, few studies have reported on the anti-melanoma activities of SH003 and FMN. This work aimed to elucidate the anti-melanoma effects of SH003 and FMN through the PD-1/PD-L1 pathway, using B16F10 cells and CTLL-2 cells. Results showed that SH003 and FMN reduced melanin content and tyrosinase activity induced by α-MSH. Moreover, SH003 and FMN suppressed B16F10 growth and arrested cells at the G2/M phase. SH003 and FMN also led to cell apoptosis with increases in PARP and caspase-3 activation. The pro-apoptotic effects were further enhanced when combined with cisplatin. In addition, SH003 and FMN reversed the increased PD-L1 and STAT1 phosphorylation levels induced by cisplatin in the presence of IFN-γ. SH003 and FMN also enhanced the cytotoxicity of CTLL-2 cells against B16F10 cells. Therefore, the mixture of natural products SH003 demonstrates therapeutic potential in cancer treatment by exerting anti-melanoma effects through the PD-1/PD-L1 pathway.

PD-1/PD-L1 immune checkpoint blockade in ovarian cancer: dilemmas and opportunities

Immune checkpoint inhibitors (ICIs) have revolutionized treatment in oncology. Antibodies against PD-1/PD-L1 and ICI-based combinations are under clinical investigations in multiple cancers, including ovarian cancer. However, the success of ICIs has not materialized in ovarian cancer, which remains one of the few malignancies where ICIs exhibit modest efficacy as either monotherapy or combination therapy. In this review, we summarize completed and ongoing clinical trials of PD-1/PD-L1 blockade in ovarian cancer, categorize the underlying mechanisms of resistance emergence, and introduce candidate approaches to rewire the tumor microenvironment (TME) to potentiate anti-PD-1/PD-L1 antibodies. Teaser: The intrinsic resistance of ovarian cancer to PD-1/PD-L1 blockade could be overcome by advanced understanding of underlying mechanisms and discoveries of new actionable targets for combinatory treatment.

Progress towards Adjuvant Development: Focus on Antiviral Therapy

In recent decades, vaccines have been extraordinary resources to prevent pathogen diffusion and cancer. Even if they can be formed by a single antigen, the addition of one or more adjuvants represents the key to enhance the response of the immune signal to the antigen, thus accelerating and increasing the duration and the potency of the protective effect. Their use is of particular importance for vulnerable populations, such as the elderly or immunocompromised people. Despite their importance, only in the last forty years has the search for novel adjuvants increased, with the discovery of novel classes of immune potentiators and immunomodulators. Due to the complexity of the cascades involved in immune signal activation, their mechanism of action remains poorly understood, even if significant discovery has been recently made thanks to recombinant technology and metabolomics. This review focuses on the classes of adjuvants under research, recent mechanism of action studies, as well as nanodelivery systems and novel classes of adjuvants that can be chemically manipulated to create novel small molecule adjuvants.

Localized chemotherapy approaches and advanced drug delivery strategies: a step forward in the treatment of peritoneal carcinomatosis from ovarian cancer

Peritoneal carcinomatosis (PC) is a common outcome of epithelial ovarian carcinoma and is the leading cause of death for these patients. Tumor location, extent, peculiarities of the microenvironment, and the development of drug resistance are the main challenges that need to be addressed to improve therapeutic outcome. The development of new procedures such as HIPEC (Hyperthermic Intraperitoneal Chemotherapy) and PIPAC (Pressurized Intraperitoneal Aerosol Chemotherapy) have enabled locoregional delivery of chemotherapeutics, while the increasingly efficient design and development of advanced drug delivery micro and nanosystems are helping to promote tumor targeting and penetration and to reduce the side effects associated with systemic chemotherapy administration. The possibility of combining drug-loaded carriers with delivery via HIPEC and PIPAC represents a powerful tool to improve treatment efficacy, and this possibility has recently begun to be explored. This review will discuss the latest advances in the treatment of PC derived from ovarian cancer, with a focus on the potential of PIPAC and nanoparticles in terms of their application to develop new therapeutic strategies and future prospects.

Modulation of immune checkpoint regulators in interferon γ induced urothelial carcinoma and activated T-lymphocyte cells by cytostatics

Exploring the regulation of co-inhibitory (PD-1, PD-L1, CTLA-4) and co-stimulatory (CD28) genes by chemotherapeutic drugs is important for combined immune checkpoint blockade (ICB) therapy. ICB interferes with T-cell receptor and major histocompatibility complex (MHC) signaling by antibody drugs directed against the co-inhibitors. Here, we analyzed urothelial (T24) cell line with respect to cytokine signaling by interferon γ (IFNG) and the leukemia lymphocyte (Jurkat) cell line with respect to T-cell activation as mimicked by phorbolester and calcium ionophore (pma/iono). Alongside, we considered possible intervention with the chemotherapeutics gemcitabine, cisplatin and vinflunine. Noteworthy, cisplatin significantly induced PD-L1-mRNA in naïve and IFNG treated cells whereas gemcitabine and vinflunine had no effect on PD-L1-mRNA. At the protein level, PD-L1 showed typical induction in IFNG treated cells. In Jurkat cells, cisplatin significantly induced PD-1-mRNA and PD-L1-mRNA. Pma/iono administration did not alter PD-1-mRNA and PD-L1-mRNA but significantly increased CTLA-4-mRNA and CD28-mRNA levels where vinflunine suppressed the CD28-mRNA induction. In sum, we demonstrated that certain cytostatic drugs being relevant for the therapy of urothelial cancer, affect co-inhibitory and co-stimulatory modulators of immune signaling with potential impact for perspective combined ICB therapy of patients. MHC-TCR signaling between antigen presenting cells and T-lymphocytes with co-stimulator (blue) and co-inhibitors (red) and interacting proteins (blank). Co-inhibitory connections are shown by lines and co-stimulatory connections by dotted lines. The inducible or suppressive actions of the drugs (underlined) on the respective targets are indicated.

Perfusion Air Culture of Precision-Cut Tumor Slices: An Ex Vivo System to Evaluate Individual Drug Response under Controlled Culture Conditions

Precision-cut tumor slices (PCTS) maintain tissue heterogeneity concerning different cell types and preserve the tumor microenvironment (TME). Typically, PCTS are cultured statically on a filter support at an air-liquid interface, which gives rise to intra-slice gradients during culture. To overcome this problem, we developed a perfusion air culture (PAC) system that can provide a continuous and controlled oxygen medium, and drug supply. This makes it an adaptable ex vivo system for evaluating drug responses in a tissue-specific microenvironment. PCTS from mouse xenografts (MCF-7, H1437) and primary human ovarian tumors (primary OV) cultured in the PAC system maintained the morphology, proliferation, and TME for more than 7 days, and no intra-slice gradients were observed. Cultured PCTS were analyzed for DNA damage, apoptosis, and transcriptional biomarkers for the cellular stress response. For the primary OV slices, cisplatin treatment induced a diverse increase in the cleavage of caspase-3 and PD-L1 expression, indicating a heterogeneous response to drug treatment between patients. Immune cells were preserved throughout the culturing period, indicating that immune therapy can be analyzed. The novel PAC system is suitable for assessing individual drug responses and can thus be used as a preclinical model to predict in vivo therapy responses.

Epigenetic-Metabolic Interplay in the DNA Damage Response and Therapeutic Resistance of Breast Cancer

Therapy resistance is imposing a daunting challenge on effective clinical management of breast cancer. Although the development of resistance to drugs is multifaceted, reprogramming of energy metabolism pathways is emerging as a central but heterogenous regulator of this therapeutic challenge. Metabolic heterogeneity in cancer cells is intricately associated with alterations of different signaling networks and activation of DNA damage response pathways. Here we consider how the dynamic metabolic milieu of cancer cells regulates their DNA damage repair ability to ultimately contribute to development of therapy resistance. Diverse epigenetic regulators are crucial in remodeling the metabolic landscape of cancer. This epigenetic-metabolic interplay profoundly affects genomic stability of the cancer cells as well as their resistance to genotoxic therapies. These observations identify defining mechanisms of cancer epigenetics-metabolism-DNA repair axis that can be critical for devising novel, targeted therapeutic approaches that could sensitize cancer cells to conventional treatment strategies.

Discordance of PD-L1 expression in primary and metastatic ovarian high-grade serous carcinoma and its correlation with CD8 + tumor-infiltrating lymphocytes and patient prognosis

Differential expression of programmed death-1 ligand (PD-L1) and its clinical significance in primary and metastatic ovarian high-grade serous carcinoma (HGSC) have not been defined. Thus, we investigated the PD-L1 expression of paired ovarian primary and omental metastatic HGSC and its correlation with CD8 + tumor-infiltrating lymphocyte (TILs) and patient survival. A total of 212 cases of ovarian HGSCs with matched primary ovarian and metastatic omental tumors accessioned between 2003 and 2018 were selected for further analysis. Using immunohistochemistry, we evaluated the density of CD8 + TILs and expression of PD-L1 on whole tissue sections. Applying tumor proportion score (TPS, cutoff 1%) and combined positive score (CPS, cutoff 1), the prevalence of PD-L1 expression was similar but with significant discordance in ovarian and omental tumor. Using TPS, patients with PD-L1-positive tumors demonstrated significantly worse recurrence free survival (RFS) and overall survival (OS) than patients with PD-L1-negative tumors. Using CPS, patients with PD-L1-positive ovarian tumors demonstrated significantly worse OS while no significant difference in RFS was found. Patients with PD-L1-positive omental tumors demonstrated significantly worse RFS and OS. Patients with omental PD-L1-positive tumors (TPS) were associated with poorer RFS and OS, while patients with ovarian PD-L1-positive tumors (TPS) were associated with OS not RFS, in COX multivariant analysis. Nonetheless, ovarian and omental high CD8 TILs density was not associated with worse OS in univariant and COX multivariant analysis. PD-L1 expression in ovarian and omental tumor associated with an increased CD8 + TILs density. PD-L1 expression by TPS was better correlated with survival than by CPS, and PD-L1 expression in omental tumors was a stronger prognostic indicator than that in ovarian tumors.

Effect of celecoxib plus standard chemotherapy on cancer prognosis: A systematic review and meta-analysis

BACKGROUND

Inflammation is closely related to cancer prognosis. The effect of celecoxib, a nonsteroidal anti-inflammatory drug, on the prognosis of patients with cancer remains uncertain. To assess the association between celecoxib plus standard chemotherapy and cancer prognosis, we conducted a systematic review and meta-analysis of published studies.

METHODS

PubMed, EMBASE, and the Cochrane Library were searched from inception until July 2022 for randomized controlled trials reporting the prognosis of patients with cancer treated with celecoxib plus standard chemotherapy. The primary endpoints were overall survival (OS) and progression-free survival (PFS). Meta-analysis was performed using Review Manager software version 5.4. The following search terms were used in the databases: ((((celecoxib)) AND ((((((((cancer) OR (carcinoma)) OR (sarcoma)) OR (neoplasms)) OR (tumor)) OR (tumour)) OR (tumors)) OR (tumours))) AND ((survival) OR (mortality))) AND (((Clinical Trials, Randomized) OR (Trials, Randomized Clinical)) OR (Controlled Clinical Trials, Randomized)).

RESULTS

Overall, 13 randomized controlled trials, including 8957 patients with cancer, were included in the analysis. Compared to conventional chemotherapy alone, 1-year OS and 1-year PFS rates were not significantly improved with celecoxib adjuvant therapy (OS: p = .38; PFS: p = .65). In addition, no differences were observed between the celecoxib and placebo groups in 3-year overall (p = .98), 3-year progression-free (p = .40), 5-year overall (p = .59), or 5-year progression-free (p = .56) survival rates. An increase in the risk ratio of leukopenia (p = .02) and thrombocytopenia (p = .05) was also observed, suggesting that celecoxib promotes hematologic toxicity. No increased risk of cardiovascular (p = .96) and gastrointestinal (p = .10-.91) events was observed.

CONCLUSIONS

The addition of celecoxib to standard chemotherapy did not improve OS or PFS rates of patients with cancer. Additionally, celecoxib can increase hematologic toxicity without increasing the risk of gastrointestinal or cardiovascular reactions. Further randomized controlled trials are necessary to clarify its effects and applications.