Niraparib activates interferon signaling and potentiates anti-PD-1 antibody efficacy in tumor models

Reversal of T-cell exhaustion: Mechanisms and synergistic approaches

T cells suffer from long-term antigen stimulation and insufficient energy supply, leading to a decline in their effector functions, memory capabilities, and proliferative capacity, ultimately resulting in T cell exhaustion and an inability to perform normal immune functions in the tumor microenvironment. Therefore, exploring how to restore these exhausted T cells to a state with effector functions is of great significance. Exhausted T cells exhibit a spectrum of molecular alterations, such as heightened expression of inhibitory receptors, shifts in transcription factor profiles, and modifications across epigenetic, metabolic, and transcriptional landscapes. This review provides a comprehensive overview of various strategies to reverse T cell exhaustion, including immune checkpoint blockade, and explores the potential synergistic effects of combining multiple approaches to reverse T cell exhaustion. It offers new insights and methods for achieving more durable and effective reversal of T cell exhaustion.

Clinically Relevant Humanized Mouse Models of Metastatic Prostate Cancer Facilitate Therapeutic Evaluation

There is tremendous need for improved prostate cancer models. Anatomically and developmentally, the mouse prostate differs from the human prostate and does not form tumors spontaneously. Genetically engineered mouse models lack the heterogeneity of human cancer and rarely establish metastatic growth. Human xenografts are an alternative but must rely on an immunocompromised host. Therefore, we generated prostate cancer murine xenograft models with an intact human immune system (huNOG and huNOG-EXL mice) to test whether humanizing tumor-immune interactions would improve modeling of metastatic prostate cancer and the impact of androgen receptor-targeted and immunotherapies. These mice maintain multiple human immune cell lineages, including functional human T-cells and myeloid cells. Implications: To the best of our knowledge, results illustrate the first model of human prostate cancer that has an intact human immune system, metastasizes to clinically relevant locations, responds appropriately to standard-of-care hormonal therapies, and can model both an immunosuppressive and checkpoint-inhibition responsive immune microenvironment.

Strategies for the prevention or reversal of PARP inhibitor resistance

INTRODUCTION

Advances in our understanding of tumor biology shed light on hallmarks of cancer development and progression that include dysregulated DNA damage repair (DDR) machinery. Leveraging the underlying tumor genomic instability and tumor-specific defects in DDR, Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) induced DNA damage emerges as a novel non-chemotherapy therapeutic opportunity. PARPis are currently approved in multiple tumor types, with the largest benefit seen in tumors with homologous recombination repair (HRR) deficiency, including germline and somatic mutations in BRCA1/2 genes (BRCA) and other pathway members such as PALB2 and Rad51c.

AREAS COVERED

This review article summarizes the current approval landscape and known and proposed mechanisms of resistance to PARPi. Further, therapeutic strategies to overcome PARPi resistance are discussed, including ongoing clinical trials.

EXPERT OPINION

PARPi have proven to be a safe and effective therapy and represents a cornerstone treatment across multiple solid tumor types. Elucidating innate and acquired mechanisms of resistance, coupled with the emergence of novel therapeutic options to capitalize on the activity of PARPi and prevent or reverse the acquisition of resistance, provides an opportunity to further expand the role of PARPi in cancer therapy.

Combined strategies with PARP inhibitors for the treatment of BRCA wide type cancer

Genomic instability stands out as a pivotal hallmark of cancer, and PARP inhibitors (PARPi) emerging as a groundbreaking class of targeted therapy drugs meticulously crafted to inhibit the repair of DNA single-strand breaks(SSB) in tumor cells. Currently, PARPi have been approved for the treatment of ovarian cancer, pancreatic cancer, breast cancer, and prostate cancer characterized by homologous recombination(HR) repair deficiencies due to mutations in BRCA1/2 or other DNA repair associated genes and acquiring the designation of breakthrough therapy. Nonetheless, PARPi exhibit limited efficacy in the majority of HR-proficient BRCA1/2 wild-type cancers. At present, the synergistic approach of combining PARPi with agents that induce HR defects, or with chemotherapy and radiotherapy to induce substantial DNA damage, significantly enhances the efficacy of PARPi in BRCA wild-type or HR-proficient patients, supporting extension the use of PARPi in HR proficient patients. Therefore, we have summarized the effects and mechanisms of the combined use of drugs with PARPi, including the combination of PARPi with HR defect-inducing drugs such as ATRi, CHKi, HR indirectly inducing drugs like VEGFRi, CDKi, immune checkpoint inhibitors and drugs instigating DNA damage such as chemotherapy or radiotherapy. In addition, this review discusses several ongoing clinical trials aimed at analyzing the clinical application potential of these combined treatment strategies.

Genome-wide CRISPR screening identifies tyrosylprotein sulfotransferase-2 as a target for augmenting anti-PD1 efficacy

BACKGROUND

Immune checkpoint therapy (ICT) provides durable responses in select cancer patients, yet resistance remains a significant challenge, prompting the exploration of underlying molecular mechanisms. Tyrosylprotein sulfotransferase-2 (TPST2), known for its role in protein tyrosine O-sulfation, has been suggested to modulate the extracellular protein-protein interactions, but its specific role in cancer immunity remains largely unexplored.

METHODS

To explore tumor cell-intrinsic factors influencing anti-PD1 responsiveness, we conducted a pooled loss-of-function genetic screen in humanized mice engrafted with human immune cells. The responsiveness of cancer cells to interferon-γ (IFNγ) was estimated by evaluating IFNγ-mediated induction of target genes, STAT1 phosphorylation, HLA expression, and cell growth suppression. The sulfotyrosine-modified target gene of TPST2 was identified by co-immunoprecipitation and mass spectrometry. The in vivo effects of TPST2 inhibition were evaluated using mouse syngeneic tumor models and corroborated by bulk and single-cell RNA sequencing analyses.

RESULTS

Through in vivo genome-wide CRISPR screening, TPST2 loss-of-function emerged as a potential enhancer of anti-PD1 treatment efficacy. TPST2 suppressed IFNγ signaling by sulfating IFNγ receptor 1 at Y397 residue, while its downregulation boosted IFNγ-mediated signaling and antigen presentation. Depletion of TPST2 in cancer cells augmented anti-PD1 antibody efficacy in syngeneic mouse tumor models by enhancing tumor-infiltrating lymphocytes. RNA sequencing data revealed TPST2's inverse correlation with antigen presentation, and increased TPST2 expression is associated with poor prognosis and altered cancer immunity across cancer types.

CONCLUSIONS

We propose TPST2's novel role as a suppressor of cancer immunity and advocate for its consideration as a therapeutic target in ICT-based treatments.

Towards targeting the breast cancer immune microenvironment

The tumour immune microenvironment is shaped by the crosstalk between cancer cells, immune cells, fibroblasts, endothelial cells and other stromal components. Although the immune tumour microenvironment (TME) serves as a source of therapeutic targets, it is also considered a friend or foe to tumour-directed therapies. This is readily illustrated by the importance of T cells in triple-negative breast cancer (TNBC), culminating in the advent of immune checkpoint therapy in combination with cytotoxic chemotherapy as standard of care for both early and advanced-stage TNBC, as well as recent promising signs of efficacy in a subset of hormone receptor-positive disease. In this Review, we discuss the various components of the immune TME in breast cancer and therapies that target or impact the immune TME, as well as the complexity of host physiology.

ATM, BLM, and CDH1 gene co-mutations in a high-grade endometrial stromal sarcoma patient with multiple abdominal cavity metastases: a case report and literature review

BACKGROUND

High-grade endometrial stromal sarcoma (HG-ESS) is a rare malignant tumor with poor prognosis. To overcome the limitations of current treatment for advanced patients, the intervention of targeted drug therapy is urgently needed.

CASE PRESENTATION

A 74-year-old married woman who presented with abdominal distension and lower abdominal pain was admitted to Hebei General Hospital. After surgery, immunohistochemical staining revealed a malignant tumor which was consistent with HG-ESS. Tumor recurrence occurred 2 months after surgery. Then the patient underwent chemotherapy with two courses but responded poorly. Subsequently we observed ATM, BLM, and CDH1 co-mutations by Next Generation Sequencing (NGS). Then the patient received pamiparib, which resulted in a 10-month progression-free survival (PFS) and is now stable with the administration of sintilimab in combination with pamiparib and anlotinib.

CONCLUSIONS

Due to the successful use of poly ADP-ribose polymerase inhibitor (PARPi) on HG-ESS, we suggest that the selection of effective targeted drugs combined with anti- programmed death-1 (PD-1) drug therapy based on genetic testing may become a new option for the treatment of homologous repair deficient (HR-deficient) HG-ESS.

Assessing the benefits and safety profile of incorporating poly ADP-ribose polymerase (PARP) inhibitors in the treatment of advanced lung cancer: a thorough systematic review and meta-analysis

Background

Poly (ADP-Ribose) Polymerase (PARP) inhibitors represent a novel class of drugs that hinder DNA repair mechanisms in tumor cells, leading to cell death. This systematic review aims to evaluate the effectiveness, safety, and potential adverse effects of PARP inhibitors (PARPi) in the management of patients with advanced lung cancer.

Materials and Methods

We conducted a comprehensive search for relevant studies in PubMed, Embase, Cochrane, and ClinicalTrials.gov. We extracted primary and secondary outcome measures, including progression-free survival (PFS), overall survival (OS), and adverse events (AEs), from the identified literature for subsequent meta-analysis and systematic review.

Results

This study encompassed twelve randomized controlled trials, involving 3,132 patients with advanced lung cancer. In comparison to non-PARPi treatments, the administration of PARPi significantly extended OS (hazard ratio (HR) = 0.90, 95% CI = 0.83-0.97, p = 0.006). However, the difference in PFS did not reach statistical significance.

Conclusion

In summary, therapies incorporating PARPi provide a degree of benefit by extending OS in patients with advanced lung cancer. Nonetheless, further trials are necessary to furnish additional evidence regarding the efficacy and safety of PARPi in the treatment of lung cancer.

Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/, identifier number: CRD42023424673.

Prediction of Tumor-Associated Macrophages and Immunotherapy Benefits Using Weakly Supervised Contrastive Learning in Breast Cancer Pathology Images

The efficacy of immune checkpoint inhibitors is significantly influenced by the tumor immune microenvironment (TIME). RNA sequencing of tumor tissue can offer valuable insights into TIME, but its high cost and long turnaround time seriously restrict its utility in routine clinical examinations. Several recent studies have suggested that ultrahigh-resolution pathology images can infer cellular and molecular characteristics. However, few study pay attention to the quantitative estimation of various tumor infiltration immune cells from pathology images. In this paper, we integrated contrastive learning and weakly supervised learning to infer tumor-associated macrophages and potential immunotherapy benefit from whole slide images (WSIs) of H &E stained pathological sections. We split the high-resolution WSIs into tiles and then apply contrastive learning to extract features of each tile. After aggregating the features at the tile level, we employ weak supervisory signals to fine-tune the encoder for various downstream tasks. Comprehensive experiments on two independent breast cancer cohorts and spatial transcriptomics data demonstrate that the computational pathological features accurately predict the proportion of tumor-infiltrating immune cells, particularly the infiltration level of macrophages, as well as the immune subtypes and potential immunotherapy benefit. These findings demonstrate that our model effectively captures pathological features beyond human vision, establishing a mapping relationship between cellular compositions and histological morphology, thus expanding the clinical applications of digital pathology images.

Androgen receptor, PARP signaling, and tumor microenvironment: the 'perfect triad' in prostate cancer?

Aberrations in the homologous recombination repair (HRR) pathway in prostate cancer (PCa) provide a unique opportunity to develop therapeutic strategies that take advantage of the reduced tumor ability to repair DNA damage. Poly-ADP-ribose polymerase (PARP) inhibitors (PARPi) have been shown to prolong the survival of PCa patients with HRR defects, particularly in those with Breast Cancer type 1 susceptibility protein/Breast Cancer type 2 susceptibility protein alterations. To expand the benefit of PARPi to patients without detectable HRR alterations, multiple preclinical and clinical studies are addressing potential synergies between PARPi and androgen receptor signaling inhibitors, and these strategies are also being evaluated in combination with other drugs such as immune checkpoint inhibitors. However, the effectiveness of these combining therapies could be hindered by multiple mechanisms of resistance, including also the role played by the immunosuppressive tumor microenvironment. In this review, we summarize the use of PARPi in PCa and the potential synergies with different molecular pathways. However, numerous unanswered questions remain, including the identification of the patient population that could benefit most from PARPi, determining whether to use PARPi as monotherapy or in combination, and finding the optimal timing of PARPi, expanding the use of genomic tests, and optimizing combination therapies.

Niraparib enhances antitumor immunity and contributes to the efficacy of PD-L1 blockade in cervical cancer

PURPOSE

With the development of immunotherapy research, the role of immune checkpoint blockade (ICB) in the treatment of cervical cancer has been emphasized, but many patients still can't receive long-term benefits from ICB. Poly ADP ribose polymerase inhibitor (PARPi) has been proved to exert significant antitumor effects in multiple solid tumors. Whether cervical cancer patients obtain better benefits from the treatment regimen of PARPi combined with ICB remains unclear.

METHODS

The alteration of PD-L1 expression induced by niraparib in cervical cancer cells and its underlying mechanism were assessed by western blot and immunofluorescence and quantitative real-time polymerase chain reaction (qRT-PCR).The regulation of PTEN by KDM5A was confirmed using Chromatin immunoprecipitation (ChIP) assay and RNA interference. Analyzing the relationship between PD-L1 and immune effector molecules through searching online databases. Therapeutic efficacy of niraparib, PD-L1 blockade or combination was assessed in syngeneic tumor model. The changes of immune cells and cytokines in vivo was detected by immunohistochemistry (IHC) and qRT-PCR.

RESULTS

We found that niraparib upregulated PD-L1 expression and potentiated the antitumor effects of PD-L1 blockade in a murine cervical cancer model. Niraparib inhibited the Pten expression by increasing the abundance of KDM5A, which expanded PD-L1 abundance through activating the PI3K-AKT-S6K1 pathway. PD-L1 was positively correlated with immune effector molecules including TNF-α, IFN-γ, granzyme A and granzyme B based on biological information analysis. Niraparib increased the infiltration of CD8+ T cells and the level of IFN-γ, granzyme B in vivo.

CONCLUSION

Our findings demonstrates the regulation of niraparib on local immune microenvironment of cervical cancer, and provides theoretical basis for supporting the combination of PARPi and PD-L1 blockade as a potential treatment for cervical cancer.

Beyond monotherapy: An era ushering in combinations of PARP inhibitors with immune checkpoint inhibitors for solid tumors

The introduction of PARP inhibitors (PARPis) and immune checkpoint inhibitors (ICIs) has marked a significant shift in the treatment landscape for solid tumors. Emerging preclinical evidence and initial clinical trials have indicated that the synergistic application of PARPis and ICIs may enhance treatment efficacy and potentially improve long-term patient outcomes. Nonetheless, how to identify specific tumor types and molecular subgroups most likely to benefit from this combination remains an area of ongoing research. This review thoroughly examines current studies on the co-administration of PARPis and ICIs across various solid tumors. It explores the underlying mechanisms of action, evaluates clinical efficacy, identifies potential responder populations, and delineates common adverse events alongside strategic management approaches. The aim is to offer a detailed understanding of this combination therapy, potentially guiding future therapeutic strategies for solid tumors.

C5aR1 inhibition reprograms tumor associated macrophages and reverses PARP inhibitor resistance in breast cancer

Although Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) have been approved in multiple diseases, including BRCA1/2 mutant breast cancer, responses are usually transient requiring the deployment of combination therapies for optimal efficacy. Here we thus explore mechanisms underlying sensitivity and resistance to PARPi using two intrinsically PARPi sensitive (T22) and resistant (T127) syngeneic murine breast cancer models in female mice. We demonstrate that tumor associated macrophages (TAM) potentially contribute to the differential sensitivity to PARPi. By single-cell RNA-sequencing, we identify a TAM_C3 cluster, expressing genes implicated in anti-inflammatory activity, that is enriched in PARPi resistant T127 tumors and markedly decreased by PARPi in T22 tumors. Rps19/C5aR1 signaling is selectively elevated in TAM_C3. C5aR1 inhibition or transferring C5aR1hi cells increases and decreases PARPi sensitivity, respectively. High C5aR1 levels in human breast cancers are associated with poor responses to immune checkpoint blockade. Thus, targeting C5aR1 may selectively deplete pro-tumoral macrophages and engender sensitivity to PARPi and potentially other therapies.

Niraparib, Dostarlimab, and Bevacizumab as Combination Therapy in Pretreated, Advanced Platinum-Resistant Ovarian Cancer: Findings From Cohort A of the OPAL Phase II Trial

PURPOSE

To report the results of OPAL (ClinicalTrials.gov identifier: NCT03574779) cohort A, a single-arm substudy of niraparib plus dostarlimab and bevacizumab for the treatment of advanced, platinum-resistant ovarian cancer (PROC).

METHODS

Participants with PROC who received 1-2 previous lines of therapy were treated with niraparib (200 or 300 mg once daily), dostarlimab (500 mg once every 3 weeks for four 21-day cycles, followed by 1,000 mg once every 6 weeks), and bevacizumab (15 mg/kg once every 3 weeks). The primary end point was investigator-assessed objective response rate (ORR) per RECIST v1.1. Safety was also assessed. Exploratory biomarker end points included evaluation of changes in the tumor molecular profile and microenvironment using baseline and on-treatment tumor samples.

RESULTS

Of 41 enrolled participants (median age, 66.0 years [range, 37-83 years]), 9.8% had tumors that were BRCA-mutated, 19.5% were homologous recombination (HR)-deficient, and 17.1% were HR repair (HRR)-mutated. As of the cutoff date, all participants discontinued treatment. The ORR was 17.1% (80% CI, 9.8 to 27.0), including one complete response (2.4%); the disease control rate was 73.2% (80% CI, 62.3 to 82.2). Two participants withdrew before first postbaseline scan because of adverse events (AEs). Grade ≥3 treatment-emergent AEs were reported in 92.7% of participants, with the most common being hypertension (26.8%). Response was not correlated with BRCA, HRR, HR deficiency (HRD), or PD-L1 status. Changes suggesting immune activation were observed in on-treatment samples after triplet therapy.

CONCLUSION

Results demonstrated modest activity of niraparib, dostarlimab, and bevacizumab in participants with PROC, many of whom had prognostic factors for poor treatment response. Most participants with response were bevacizumab-naïve. No association was found with HRD, BRCA, or PD-L1 status. AEs were consistent with previous monotherapy reports, except that hypertension was reported more frequently.

Network integration of thermal proteome profiling with multi-omics data decodes PARP inhibition

Complex disease phenotypes often span multiple molecular processes. Functional characterization of these processes can shed light on disease mechanisms and drug effects. Thermal Proteome Profiling (TPP) is a mass-spectrometry (MS) based technique assessing changes in thermal protein stability that can serve as proxies of functional protein changes. These unique insights of TPP can complement those obtained by other omics technologies. Here, we show how TPP can be integrated with phosphoproteomics and transcriptomics in a network-based approach using COSMOS, a multi-omics integration framework, to provide an integrated view of transcription factors, kinases and proteins with altered thermal stability. This allowed us to recover consequences of Poly (ADP-ribose) polymerase (PARP) inhibition in ovarian cancer cells on cell cycle and DNA damage response as well as interferon and hippo signaling. We found that TPP offers a complementary perspective to other omics data modalities, and that its integration allowed us to obtain a more complete molecular overview of PARP inhibition. We anticipate that this strategy can be used to integrate functional proteomics with other omics to study molecular processes.

The Killer's Web: Interconnection between Inflammation, Epigenetics and Nutrition in Cancer

Inflammation is a key contributor to both the initiation and progression of tumors, and it can be triggered by genetic instability within tumors, as well as by lifestyle and dietary factors. The inflammatory response plays a critical role in the genetic and epigenetic reprogramming of tumor cells, as well as in the cells that comprise the tumor microenvironment. Cells in the microenvironment acquire a phenotype that promotes immune evasion, progression, and metastasis. We will review the mechanisms and pathways involved in the interaction between tumors, inflammation, and nutrition, the limitations of current therapies, and discuss potential future therapeutic approaches.

PARP inhibitors for prostate cancer

Poly(ADP-ribose) polymerase (PARP) inhibitors have transformed the treatment landscape for patients with metastatic castration-resistant prostate cancer (mCRPC) and alterations in DNA damage response genes. This has also led to widespread use of genomic testing in all patients with mCRPC. The current review will give an overview of (1) the current understanding of the interplay between DNA damage response and PARP enzymes; (2) the clinical landscape of PARP inhibitors, including the combination of PARP inhibitors with other agents such as androgen-receptor signaling agents; (3) biomarkers related to PARP inhibitor response and resistance; and (4) considerations for interpreting genomic testing results and treating patients with PARP inhibitors.

PARP1 roles in DNA repair and DNA replication: The basi(c)s of PARP inhibitor efficacy and resistance

Genome integrity is under constant insult from endogenous and exogenous sources. In order to cope, eukaryotic cells have evolved an elaborate network of DNA repair that can deal with diverse lesion types and exhibits considerable functional redundancy. PARP1 is a major sensor of DNA breaks with established and putative roles in a number of pathways within the DNA repair network, including repair of single- and double-strand breaks as well as protection of the DNA replication fork. Importantly, PARP1 is the major target of small-molecule PARP inhibitors (PARPi), which are employed in the treatment of homologous recombination (HR)-deficient tumors, as the latter are particularly susceptible to the accumulation of DNA damage due to an inability to efficiently repair highly toxic double-strand DNA breaks. The clinical success of PARPi has fostered extensive research into PARP biology, which has shed light on the involvement of PARP1 in various genomic transactions. A major goal within the field has been to understand the relationship between catalytic inhibition and PARP1 trapping. The specific consequences of inhibition and trapping on genomic stability as a basis for the cytotoxicity of PARP inhibitors remain a matter of debate. Finally, PARP inhibition is increasingly recognized for its capacity to elicit/modulate anti-tumor immunity. The clinical potential of PARP inhibition is, however, hindered by the development of resistance. Hence, extensive efforts are invested in identifying factors that promote resistance or sensitize cells to PARPi. The current review provides a summary of advances in our understanding of PARP1 biology, the mechanistic nature, and molecular consequences of PARP inhibition, as well as the mechanisms that give rise to PARPi resistance.

Phase I study of peposertib and avelumab with or without palliative radiotherapy in patients with advanced solid tumors

INTRODUCTION

We report results from a phase I, three-part, dose-escalation study of peposertib, a DNA-dependent protein kinase inhibitor, in combination with avelumab, an immune checkpoint inhibitor, with or without radiotherapy in patients with advanced solid tumors.

MATERIALS AND METHODS

Peposertib 100-400 mg twice daily (b.i.d.) or 100-250 mg once daily (q.d.) was administered in combination with avelumab 800 mg every 2 weeks in Part A or avelumab plus radiotherapy (3 Gy/fraction × 10 days) in Part B. Part FE assessed the effect of food on the pharmacokinetics of peposertib plus avelumab. The primary endpoint in Parts A and B was dose-limiting toxicity (DLT). Secondary endpoints were safety, best overall response per RECIST version 1.1, and pharmacokinetics. The recommended phase II dose (RP2D) and maximum tolerated dose (MTD) were determined in Parts A and B.

RESULTS

In Part A, peposertib doses administered were 100 mg (n = 4), 200 mg (n = 11), 250 mg (n = 4), 300 mg (n = 6), and 400 mg (n = 4) b.i.d. Of DLT-evaluable patients, one each had DLT at the 250-mg and 300-mg dose levels and three had DLT at the 400-mg b.i.d. dose level. In Part B, peposertib doses administered were 100 mg (n = 3), 150 mg (n = 3), 200 mg (n = 4), and 250 mg (n = 9) q.d.; no DLT was reported in evaluable patients. Peposertib 200 mg b.i.d. plus avelumab and peposertib 250 mg q.d. plus avelumab and radiotherapy were declared as the RP2D/MTD. No objective responses were observed in Part A or B; one patient had a partial response in Part FE. Peposertib exposure was generally dose proportional.

CONCLUSIONS

Peposertib doses up to 200 mg b.i.d. in combination with avelumab and up to 250 mg q.d. in combination with avelumab and radiotherapy were tolerable in patients with advanced solid tumors; however, antitumor activity was limited.

CLINICALTRIALS

GOV IDENTIFIER

NCT03724890.

Bibliometric analysis of research trends on the combination of immune checkpoint inhibitors and PARP inhibitors in solid tumors

Introduction

Immune checkpoint inhibitors (ICIs) has made significant achievements in the therapeutics of various tumor types, and recently growing evidence from preclinical studies and clinical trials has indicated that poly-ADP-ribose polymerase inhibitors (PARPi) are exhibiting encouraging synergism with ICIs. The aim of our current study is to explore the development pattern of literature related to the combined therapy of ICIs and PARPi in solid tumors from a bibliometric perspective.

Methods

Publications concerning the combination of ICIs and PARPi in solid tumors during 2008-2022 were extracted from the WOSCC database. VOSviewer and R-bibliometrix were applied to conduct bibliometrics.

Results

In total, 1113 articles were finally included. The USA was the most dominant country, and University of Texas MD Anderson Cancer Center was the most fruitful institute. Andreas Schneeweiss ranked first concerning the amount of publications in this research domain, and Timothy Yap had the most citations on this theme. The analysis of keyword co-occurrence indicated that research frontiers were shifted from the biological mechanisms of cell death to the combined strategy of ICIs and PARPi in clinical trials.

Conclusions

Our study comprehensively examined the publications on the combination of ICIs and PARPi in solid tumors from a bibliometric perspective. The research on this topic is in its rapid growth stage, and the USA is possessing an absolutely leading position in this field by its scientific accumulations and productivity. Moreover, the research frontiers have shifted from the mechanisms of ICIs and PARPi to their combined treatment in clinical application. In summary, our results demonstrated a comprehensive overview of the knowledge atlas and a valuable reference for the future investigations in this field.

Mechanism of PARP inhibitor resistance and potential overcoming strategies

PARP inhibitors (PARPi) are a kind of cancer therapy that targets poly (ADP-ribose) polymerase. PARPi is the first clinically approved drug to exert synthetic lethality by obstructing the DNA single-strand break repair process. Despite the significant therapeutic effect in patients with homologous recombination (HR) repair deficiency, innate and acquired resistance to PARPi is a main challenge in the clinic. In this review, we mainly discussed the underlying mechanisms of PARPi resistance and summarized the promising solutions to overcome PARPi resistance, aiming at extending PARPi application and improving patient outcomes.

Dostarlimab: From preclinical investigation to drug approval and future directions

Immune checkpoint blockers (ICB) act by reverting the immunosuppressive phenotype of cancer cells, thus allowing host immune system to generate an immune response to the tumor. One of the key mechanisms targeted by ICB is the PD-1/PD-L1 axis, which lies onto the interaction between the programmed-cell death protein 1 and its ligand, overexpressed in several tumor types. This interaction leads to the inhibition of T-cell proliferation and their apoptosis and exhaustion. Anti-PD-1/PD-L1 monoclonal antibodies are now the mainstay of treatment for several advanced stage tumors. Dostarlimab is a novel IgG4 anti-PD-1 antibody which has yielded remarkable results in mismatch-repair deficient endometrial cancer and locally advanced rectal cancer. This product review will illustrate the preclinical development of dostarlimab and its pharmacological characteristics, the clinical trials published so far and the ongoing clinical investigations.

Exploiting the DNA Damage Response for Prostate Cancer Therapy

Prostate cancers that progress despite androgen deprivation develop into castration-resistant prostate cancer, a fatal disease with few treatment options. In this review, we discuss the current understanding of prostate cancer subtypes and alterations in the DNA damage response (DDR) that can predispose to the development of prostate cancer and affect its progression. We identify barriers to conventional treatments, such as radiotherapy, and discuss the development of new therapies, many of which target the DDR or take advantage of recurring genetic alterations in the DDR. We place this in the context of advances in understanding the genetic variation and immune landscape of CRPC that could help guide their use in future treatment strategies. Finally, we discuss several new and emerging agents that may advance the treatment of lethal disease, highlighting selected clinical trials.

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.

Heterogeneity and treatment landscape of ovarian carcinoma

Ovarian carcinoma is characterized by heterogeneity at the molecular, cellular and anatomical levels, both spatially and temporally. This heterogeneity affects response to surgery and/or systemic therapy, and also facilitates inherent and acquired drug resistance. As a consequence, this tumour type is often aggressive and frequently lethal. Ovarian carcinoma is not a single disease entity and comprises various subtypes, each with distinct complex molecular landscapes that change during progression and therapy. The interactions of cancer and stromal cells within the tumour microenvironment further affects disease evolution and response to therapy. In past decades, researchers have characterized the cellular, molecular, microenvironmental and immunological heterogeneity of ovarian carcinoma. Traditional treatment approaches have considered ovarian carcinoma as a single entity. This landscape is slowly changing with the increasing appreciation of heterogeneity and the recognition that delivering ineffective therapies can delay the development of effective personalized approaches as well as potentially change the molecular and cellular characteristics of the tumour, which might lead to additional resistance to subsequent therapy. In this Review we discuss the heterogeneity of ovarian carcinoma, outline the current treatment landscape for this malignancy and highlight potentially effective therapeutic strategies in development.

High-fat diet and obesity are associated with differential angiogenic gene expression in epithelial ovarian cancer

OBJECTIVE

We sought to evaluate the association between diet and angiogenic biomarkers in KpB mice, and the association between these markers, body mass index (BMI), and overall survival (OS) in high-grade serous cancers (HGSC).

METHODS

Tumors previously obtained from KpB mice subjected to high-fat diets (HFD, n = 10) or low-fat diets (LFD, n = 10) were evaluated for angiogenesis based on CD-31 microvessel density (MVD). Data from prior microarray analysis (Agilent 244 K arrays) conducted in 10 mice were utilized to assess associations between diet and angiogenetic biomarkers. Agilent (mouse) and Affymetrix Human Genome U133a probes were linked to 162 angiogenic-related genes. The associations between biomarkers, BMI, and OS were evaluated in an HGSC internal database (IDB) (n = 40). Genes with unadjusted p < 0.05 were evaluated for association with OS in the TCGA-OV database (n = 339).

RESULTS

There was no association between CD-31 and diet in mice (p = 0.66). Sixteen angiogenic-related genes passed the p < 0.05 threshold for association with HFD vs. LFD. Transforming growth factor-alpha (TGFA) demonstrated 72% higher expression in HFD vs. LFD mice (p = 0.04). Similar to the mouse study, in our HGSC IDB, higher TGFA expression correlated with higher BMI (p = 0.01) and shorter survival (p = 0.001). In the TCGA-OV dataset, BMI data was not available and there was no association between TGFA and OS (p = 0.48).

CONCLUSIONS

HFD and obesity may promote tumor progression via differential modulation of TGFA. We were unable to confirm this finding in the TCGA dataset. Further evaluation of TGFA is needed to determine if this is a target unique to obesity-driven HGSC.

Inhibition of SF3B1 improves the immune microenvironment through pyroptosis and synergizes with αPDL1 in ovarian cancer

Ovarian cancer is resistant to immune checkpoint blockade (ICB) treatment. Combination of targeted therapy and immunotherapy is a promising strategy for ovarian cancer treatment benefit from an improved immune microenvironment. In this study, Clinical Proteomic Tumor Analysis Consortium (CPTAC) and The Cancer Genome Atlas (TCGA) cohorts were used to screen prognosis and cytotoxic lymphocyte infiltration-associated genes in upregulated genes of ovarian cancer, tissue microarrays were built for further verification. In vitro experiments and mouse (C57/BL6) ovarian tumor (ID8) models were built to evaluate the synergistic effect of the combination of SF3B1 inhibitor and PD-L1 antibody in the treatment of ovarian cancer. The results show that SF3B1 is shown to be overexpressed and related to low cytotoxic immune cell infiltration in ovarian cancer. Inhibition of SF3B1 induces pyroptosis in ovarian cancer cells and releases mitochondrial DNA (mtDNA), which is englobed by macrophages and subsequently activates them (polarization to M1). Moreover, pladienolide B increases cytotoxic immune cell infiltration in the ID8 mouse model as a SF3B1 inhibitor and increases the expression of PD-L1 which can enhance the antitumor effect of αPDL1 in ovarian cancer. The data suggests that inhibition of SF3B1 improves the immune microenvironment of ovarian cancer and synergizes ICB immunotherapy, which provides preclinical evidence for the combination of SF3B1 inhibitor and ICB to ovarian cancer treatment.

New Achievements from Molecular Biology and Treatment Options for Refractory/Relapsed Ovarian Cancer-A Systematic Review

Ovarian cancer (OC) has a high rate of mortality and is the fifth most common cause of death in females all over the world. The etiology is still unclear. Numerous factors such as smoking, obesity, and unhealthy diet may affect the risk of OC. Having a family history of breast and OC is one of the main risks for developing OC. Mutations of BRCA1/2 are associated with OC risk as well. The histopathological classification of OC reveals the four most common types: serous, clear cell, endometrioid, and mucinous; these are epithelial OC types, and other types are rare. Furthermore, OC can be subdivided into types I and II. Type I tumors are most probably caused by atypical proliferative tumors. Type II tumors include high-grade carcinoma of the serous type, carcinosarcoma, and carcinoma, which are not differentiated and generally originate from tubal intraepithelial carcinoma of the serous type. Typically, type I tumors are present in early stages, usually with good prognosis. Type II tumors are classified as high-grade tumors and are most often diagnosed at advanced FIGO stages with poor prognosis. High-grade serous OC accounts for 90% of serous OC. Tumor heterogeneity aggravates OC treatment. The standard care for primary epithelial ovarian cancer (EOC) is cytoreductive surgery followed by platinum-based chemotherapy. Neoadjuvant chemotherapy can be used in certain cases followed by cytoreductive surgery. The main prognostic factor is complete tumor resection. However, about 70% of patients relapse. Resistance to chemotherapeutic agents remains a major challenge in EOC treatment, in which many different factors are involved. In recent years, the examination of molecular parameters and their prognostic impact has become increasingly relevant in EOC, and furthermore, the use of immunotherapy has expanded the therapeutic range. As the clinical need is greatest for relapsed patients, this systematic review will focus on recent advances in molecular biology with prognostic and predictive markers and treatment options for recurrent/refractory OC. Inclusion criteria for the review: potential prospective or predictive biomarkers in preclinical or clinical use in relapsed and refractory OC, prognostic impact, clinical and preclinical trials, and immunotherapy. Exclusion criteria for the review: primary OC, no full text or abstract available, not the topic mentioned above, and text not available in English. Risk of bias: the included studies were evaluated descriptively for the topics mentioned above, and data were not compared with each other. The objective is to highlight the molecular mechanisms of the most promising targeted agents under clinical investigation to demonstrate their potential relevance in recurrent/refractory OC.

Clinically relevant humanized mouse models of metastatic prostate cancer to evaluate cancer therapies

There is tremendous need for improved prostate cancer (PCa) models. The mouse prostate does not spontaneously form tumors and is anatomically and developmentally different from the human prostate. Engineered mouse models lack the heterogeneity of human cancer and rarely establish metastatic growth. Human xenografts represent an alternative but rely on an immunocompromised host. Accordingly, we generated PCa murine xenograft models with an intact human immune system (huNOG and huNOG-EXL mice) to test whether humanizing tumor-immune interactions would improve modeling of metastatic PCa and the impact of hormonal and immunotherapies. These mice maintain multiple human cell lineages, including functional human T-cells and myeloid cells. In 22Rv1 xenografts, subcutaneous tumor size was not significantly altered across conditions; however, metastasis to secondary sites differed in castrate huNOG vs background-matched immunocompromised mice treated with enzalutamide (enza). VCaP xenograft tumors showed decreases in growth with enza and anti-Programed-Death-1 treatments in huNOG mice, and no effect was seen with treatment in NOG mice. Enza responses in huNOG and NOG mice were distinct and associated with increased T-cells within tumors of enza treated huNOG mice, and increased T-cell activation. In huNOG-EXL mice, which support human myeloid development, there was a strong population of immunosuppressive regulatory T-cells and Myeloid-Derived-Suppressor-Cells (MDSCs), and enza treatment showed no difference in metastasis. Results illustrate, to our knowledge, the first model of human PCa that metastasizes to clinically relevant locations, has an intact human immune system, responds appropriately to standard-of-care hormonal therapies, and can model both an immunosuppressive and checkpoint-inhibition responsive immune microenvironment.

Update in Immunotherapy for Advanced Non-Small Cell Lung Cancer: Optimizing Treatment Sequencing and Identifying the Best Choices

The introduction of immunotherapy has brought about a paradigm shift in the management of advanced non-small cell lung cancer (NSCLC). It has not only significantly improved the prognosis of patients but has also become a cornerstone of treatment, particularly in those without oncogenic driver mutations. Immune checkpoint inhibitors (ICIs) play a crucial role in the treatment of lung cancer and can be classified into two main groups: Anti-cytotoxic T lymphocyte antigen-4 (Anti-CTLA-4) and anti-T-cell receptor programmed cell death-1 or its ligand (Anti-PD-1 and Anti-PD-L1). Certainly, the landscape of approved first line immunotherapeutic approaches has expanded to encompass monotherapy, immunotherapy-exclusive protocols, and combinations with chemotherapy. The complexity of decision-making in this realm arises due to the absence of direct prospective comparisons. However, a thorough analysis of the long-term efficacy and safety data derived from pivotal clinical trials can offer valuable insights into optimizing treatment for different patient subsets. Moreover, ongoing research is investigating emerging biomarkers and innovative therapeutic strategies that could potentially refine the current treatment approach even further. In this comprehensive review, our aim is to highlight the latest advances in immunotherapy for advanced NSCLC, including the mechanisms of action, efficacy, safety profiles, and clinical significance of ICI.

Recent advances in targeted strategies for triple-negative breast cancer

Triple-negative breast cancer (TNBC), a highly aggressive subtype of breast cancer, negatively expresses estrogen receptor, progesterone receptor, and the human epidermal growth factor receptor 2 (HER2). Although chemotherapy is the main form of treatment for patients with TNBC, the effectiveness of chemotherapy for TNBC is still limited. The search for more effective therapies is urgent. Multiple targeted therapeutic strategies have emerged according to the specific molecules and signaling pathways expressed in TNBC. These include PI3K/AKT/mTOR inhibitors, epidermal growth factor receptor inhibitors, Notch inhibitors, poly ADP-ribose polymerase inhibitors, and antibody-drug conjugates. Moreover, immune checkpoint inhibitors, for example, pembrolizumab, atezolizumab, and durvalumab, are widely explored in the clinic. We summarize recent advances in targeted therapy and immunotherapy in TNBC, with the aim of serving as a reference for the development of individualized treatment of patients with TNBC in the future.

Inhibiting PRMT5 induces DNA damage and increases anti-proliferative activity of Niraparib, a PARP inhibitor, in models of breast and ovarian cancer

BACKGROUND

Inhibitors of Poly (ADP-Ribose) Polymerases (PARP) provide clinical benefit to patients with breast and ovarian cancers, by compromising the DNA repair activity of cancer cells. Although these agents extend progression-free survival in many patients, responses can be short lived with many patients ultimately progressing. Identification of combination partners that increase dependence of cancer cells to the DNA repair activity of PARPs may represent a strategy to increase the utility of PARP inhibitors. Protein arginine methyltransferase 5 (PRMT5) regulates DNA damage response pathways through splicing and protein modification, and inhibitors of PRMT5 have recently entered clinical trials.

METHODS

The effect of PRMT5 inhibition on the levels of DNA damage and repair markers including γH2AX, RAD51, and 53BP1 was determined using high content immunofluorescent imaging. The anti-proliferative activity of the combination of PRMT5 and PARP inhibitors was evaluated using in vitro models of breast and ovarian cancers using both cell lines and ex vivo patient derived xenografts. Finally, the combinations of PRMT5 and PARP inhibitors were evaluated in cell line xenograft models in vivo.

RESULTS

Inhibition of PRMT5 by GSK3326595 led to increased levels of markers of DNA damage. The addition of GSK3326595 to the PARP inhibitor, niraparib, resulted in increased growth inhibition of breast and ovarian cancer cell lines and patient derived spheroids. In vivo, the combination improved the partial effects on tumor growth inhibition achieved by either single agent, producing complete tumor stasis and regression.

CONCLUSION

These data demonstrate that inhibition of PRMT5 induced signatures of DNA damage in models of breast and ovarian cancer. Furthermore, combination with the PARP inhibitor, Niraparib, resulted in increased anti-tumor activity in vitro and in vivo. Overall, these data suggest inhibition of PRMT5 as a mechanism to broaden and enhance the clinical application of PARP inhibitors.

Combined immune and DDR pathway classifier: A novel pathway-based classification aimed at tailoring personalized therapies for acute myeloid leukemia patients

Acute myeloid leukemia (AML) constitutes a group of lethal hematological malignancies with high heterogeneity, resulting in widely variable outcomes of targeted therapy and immunotherapy. A better basic understanding of the molecular pathways of AML would help greatly in tailoring treatments to patients. Here, we propose a novel subtyping protocol for AML combination therapy. Three datasets, namely, the TCGA-LAML, BeatAML and Leucegene datasets, were used in this study. Single-sample GSEA (ssGSEA) was performed to calculate the expression scores of 15 pathways, including immune-related, stromal-related, DNA damage repair (DDR)-related and oncogenic pathways. The consensus clustering was used to classify AML based on pathway score data. We identified four phenotypic clusters-IM+DDR-, IM-DDR-, IM-DDR+ and IM+DDR+-representing distinct pathway expression profiles. The IM+DDR- subtype exhibited the most robust immune function, and patients of IM+DDR- subtype were likely to derive the greatest benefit from immunotherapy. Patients in IM+DDR+ subtype had the second highest immune scores and the highest DDR scores, suggesting that combination therapy (immune + DDR-targeted therapy) is the optimal treatment. For patients of IM-DDR- subtype, we recommend the combination of venetoclax and PHA-665752. A-674563 and dovitinib could be combined with DDR inhibitors to treat patients in IM-DDR+ subtype. Moreover, single-cell analysis revealed that there are more immune cells clustered in the IM+DDR- subtype and higher number of monocyte-like cells, which exert immunosuppressive effects, in the IM+DDR+ subtype. These findings can be applied for molecular stratification of patients and might contribute to the development of personalized targeted therapies for AML.

The anti-PD-1 era of cervical cancer: achievement, opportunity, and challenge

Cervical cancer is one of the three major female gynecological malignancies, becoming a major global health challenge. Although about 90% of early-stage patients can be cured by surgery, advanced-stage patients still need new treatment methods to improve their efficacy, especially for those with recurrence and metastasis tumors. Anti-PD-1 is currently the most widely used immune checkpoint inhibitor, which has revolutionized cancer therapy for different types of cancer. Pembrolizumab has been approved for second-line treatment of R/M CC but has a modest overall response rate of about 15%. Therefore, multiple types of anti-PD-1 have entered clinical trials successively and evaluated the efficacy in combination with chemotherapy, targeted therapy, and immunotherapy. At the same time, the dual specific antibody of PD-1/CTLA-4 was also used in clinical trials of cervical cancer, and the results showed better than anti-PD-1 monotherapy. In addition, anti-PD-1 has also been shown to sensitize radiotherapy. Therefore, understanding the current research progress of anti-PD-1 will better guide clinical application. This review summarizes ongoing clinical trials and published studies of anti-PD-1 monotherapy and combination therapy in the treatment of cervical cancer, as well as discusses the potential molecular biological mechanisms of combination, aiming to provide the basic evidence for support anti-PD-1 in the treatment of cervical cancer and new insights in combination immunotherapy.

Generation of Orthotopic Patient-Derived Xenografts in Humanized Mice for Evaluation of Emerging Targeted Therapies and Immunotherapy Combinations for Melanoma

Current methodologies for developing PDX in humanized mice in preclinical trials with immune-based therapies are limited by GVHD. Here, we compared two approaches for establishing PDX tumors in humanized mice: (1) PDX are first established in immune-deficient mice; or (2) PDX are initially established in humanized mice; then established PDX are transplanted to a larger cohort of humanized mice for preclinical trials. With the first approach, there was rapid wasting of PDX-bearing humanized mice with high levels of activated T cells in the circulation and organs, indicating immune-mediated toxicity. In contrast, with the second approach, toxicity was less of an issue and long-term human melanoma tumor growth and maintenance of human chimerism was achieved. Preclinical trials from the second approach revealed that rigosertib, but not anti-PD-1, increased CD8/CD4 T cell ratios in spleen and blood and inhibited PDX tumor growth. Resistance to anti-PD-1 was associated with PDX tumors established from tumors with limited CD8+ T cell content. Our findings suggest that it is essential to carefully manage immune editing by first establishing PDX tumors in humanized mice before expanding PDX tumors into a larger cohort of humanized mice to evaluate therapy response.

Current Evidence and Future Perspectives about the Role of PARP Inhibitors in the Treatment of Thoracic Cancers

In recent years, poly (ADP-ribose) polymerase (PARP) inhibition has become a promising therapeutic option for several tumors, especially for those harboring a BRCA 1-2 mutation or a deficit in the homologous recombination repair (HRR) pathway. Nevertheless, to date, PARP inhibitors are still not largely used for thoracic malignancies neither as a single agent nor in combination with other treatments. Recently, a deeper understanding of HRR mechanisms, alongside the development of new targeted and immunotherapy agents, particularly against HRR-deficient tumors, traced the path to new treatment strategies for many tumor types including lung cancer and malignant pleural mesothelioma. The aim of this review is to sum up the current knowledge about cancer-DNA damage response pathways inhibition and to update the status of recent clinical trials investigating the use of PARP inhibitors, either as monotherapy or in combination with other agents for the treatment of thoracic malignancies. We will also briefly discuss available evidence on Poly(ADP-Ribose) Glycohydrolase (PARG) inhibitors, a novel promising therapeutic option in oncology.

The DNA Damage Response and Inflammation in Cancer

Genomic stability in normal cells is crucial to avoid oncogenesis. Accordingly, multiple components of the DNA damage response (DDR) operate as bona fide tumor suppressor proteins by preserving genomic stability, eliciting the demise of cells with unrepairable DNA lesions, and engaging cell-extrinsic oncosuppression via immunosurveillance. That said, DDR sig-naling can also favor tumor progression and resistance to therapy. Indeed, DDR signaling in cancer cells has been consistently linked to the inhibition of tumor-targeting immune responses. Here, we discuss the complex interactions between the DDR and inflammation in the context of oncogenesis, tumor progression, and response to therapy.

SIGNIFICANCE

Accumulating preclinical and clinical evidence indicates that DDR is intimately connected to the emission of immunomodulatory signals by normal and malignant cells, as part of a cell-extrinsic program to preserve organismal homeostasis. DDR-driven inflammation, however, can have diametrically opposed effects on tumor-targeting immunity. Understanding the links between the DDR and inflammation in normal and malignant cells may unlock novel immunotherapeutic paradigms to treat cancer.

Enhancing the anti-tumor response by combining DNA damage repair inhibitors in the treatment of solid tumors

The anti-cancer efficacy of anti-malignancy therapies is related to DNA damage. However, DNA damage-response mechanisms can repair DNA damage, failing anti-tumor therapy. The resistance to chemotherapy, radiotherapy, and immunotherapy remains a clinical challenge. Thus, new strategies to overcome these therapeutic resistance mechanisms are needed. DNA damage repair inhibitors (DDRis) continue to be investigated, with polyadenosine diphosphate ribose polymerase inhibitors being the most studied inhibitors. Evidence of their clinical benefits and therapeutic potential in preclinical studies is growing. In addition to their potential as a monotherapy, DDRis may play an important synergistic role with other anti-cancer therapies or in reversing acquired treatment resistance. Here we review the impact of DDRis on solid tumors and the potential value of combinations of different treatment modalities with DDRis for solid tumors.

Emerging agents for the treatment of advanced or metastatic NSCLC without actionable genomic alterations with progression on first-line therapy

INTRODUCTION

Lung cancer is the second most common cancer in the world and the leading cause of cancer-related mortality. Immune checkpoint inhibitors (ICIs), as monotherapy or in combination with platinum-based chemotherapy, have emerged as the standard of care first-line treatment option for patients with advanced non-small cell lung cancer (NSCLC) without actionable genomic alterations (AGAs). Despite significant improvements in patient outcomes with these regimens, primary or acquired resistance is common and most patients develop disease progression, resulting in poor survival.

AREAS COVERED

We review the current treatments commonly used for NSCLC without AGAs in the first-line and subsequent settings and describe the unmet needs for these patients in the second-line setting, including a lack of standard definitions for primary and required resistance, and few effective treatment options for patients who develop progression of their disease on first-line therapy. We describe key mechanisms of resistance to ICIs and emerging therapies that are being investigated for patients who develop progression on ICIs and platinum-based chemotherapy.

EXPERT OPINION

Emerging agents in development have a variety of different mechanisms of action and will likely change standard of care for second-line therapy and beyond for patients with NSCLC without AGAs in the future.

Metastatic Colorectal Cancer Patient with Microsatellite Stability and Germline BRAC2 Mutation Shows a Complete Response to Olaparib in Combination with a PD-1 Inhibitor and Bevacizumab: A Case Report and Review of the Literature

Metastatic colorectal cancer (mCRC) has a poor prognosis. Combining chemotherapy with targeted therapy constitutes a basic form of mCRC treatment. Immune checkpoint inhibitors have been recommended for microsatellite instability mCRC, while most patients harboring microsatellite stability (MSS) or proficient mismatch repair (pMMR) are less responsive to immunotherapy. Combinational targeted therapy, including poly-ADP ribose polymerase (PARP) inhibitors, has been considered a promising way to reverse immunotherapy resistance; however, there is no clear and consistent conclusions can be drawn from the current research. Here, we report the case of a 59-year-old woman diagnosed with stage IVB MSS mCRC who received three courses of capecitabine/oxaliplatin chemotherapy combined with bevacizumab as a first-line treatment, resulting in an overall evaluation of stable disease (-25.7%). However, the occurrence of adverse events of intolerable grade 3 diarrhea and vomiting forced the cessation of this therapy. A germline BRCA2 mutation was found by next-generation sequencing, and the patient further received a combination of olaparib, tislelizumab, and bevacizumab. This treatment regime resulted in a complete metabolic response and a partial response (-50.9%) after 3 months of treatment. Mild asymptomatic interstitial pneumonia and manageable hematologic toxicity were two adverse events associated with this combination therapy. This study provides new insights into the combination of PARP inhibitors and immunotherapy for MSS mCRC patients carrying germline BRCA2 mutations.

High FAM111B expression predicts aggressive clinicopathologic features and poor prognosis in ovarian cancer

BACKGROUNDS

Ovarian cancer (OC) is the second most common gynecological tumor with the highest mortality rate worldwide. High FAM111B expression has been reported as a predictor of poor prognosis in other cancers, but its correlation with OC has not been reported.

METHODS

Immunohistochemistry of tissue microarrays was performed to detect FAM111B expression levels in 141 OC patient tissues. The prognostic value of FAM111B was determined by Kaplan-Meier survival analysis, and correlations between FAM111B expression and clinicopathologic features were investigated by the Clu-square test. The significance of FAM111B expression was verified bioinformatically using the Gene Expression Omnibus database. Protein-protein interaction were performed to explore downstream mechanisms of FAM111B in OC.

RESULTS

Among 141 OC patients, FAM111B was positively expressed in 87.23%, 58.16%, and 87.94%; and highly expressed in 8.51%, 17.02%, and 19.86%, as evaluated by cytoplasmic, nuclear, and combined cytoplasmic/nuclear staining. FAM111B expression was positively correlated with the expression of tumor protein markers KI67, EGFR, and PDL-1. Patients with high FAM111B expression had aggressive clinicopathologic features and shorter overall survival (P value 0.0428, 0.0050, 0.0029) and progression-free survival (P value 0.0251, 0.012, 0.0596) compared to the low FAM111B expression group for cytoplasmic, nuclear, and combined cytoplasmic/nuclear groups, respectively. These results were verified using patient data from the Gene Expression Omnibus. Seventeen genes co-expressed with FAM111B were primarily involved in "negative regulation of histone modification", "hippo signaling" and "inner ear receptor cell differentiation".

CONCLUSIONS

High FAM111B expression may serve as a novel prognostic predictor and molecular therapeutic target for OC.

Polymerase θ inhibition activates the cGAS-STING pathway and cooperates with immune checkpoint blockade in models of BRCA-deficient cancer

Recently developed inhibitors of polymerase theta (POLθ) have demonstrated synthetic lethality in BRCA-deficient tumor models. To examine the contribution of the immune microenvironment to antitumor efficacy, we characterized the effects of POLθ inhibition in immunocompetent models of BRCA1-deficient triple-negative breast cancer (TNBC) or BRCA2-deficient pancreatic ductal adenocarcinoma (PDAC). We demonstrate that genetic POLQ depletion or pharmacological POLθ inhibition induces both innate and adaptive immune responses in these models. POLθ inhibition resulted in increased micronuclei, cGAS/STING pathway activation, type I interferon gene expression, CD8⁺ T cell infiltration and activation, local paracrine activation of dendritic cells and upregulation of PD-L1 expression. Depletion of CD8⁺ T cells compromised the efficacy of POLθ inhibition, whereas antitumor effects were augmented in combination with anti-PD-1 immunotherapy. Collectively, our findings demonstrate that POLθ inhibition induces immune responses in a cGAS/STING-dependent manner and provide a rationale for combining POLθ inhibition with immune checkpoint blockade for the treatment of HR-deficient cancers.

Combining targeted DNA repair inhibition and immune-oncology approaches for enhanced tumor control

Targeted therapy and immunotherapy have revolutionized cancer treatment. However, the ability of cancer to evade the immune system remains a major barrier for effective treatment. Related to this, several targeted DNA-damage response inhibitors (DDRis) are being tested in the clinic and have been shown to potentiate anti-tumor immune responses. Seminal studies have shown that these agents are highly effective in a pan-cancer class of tumors with genetic defects in key DNA repair genes such as BRCA1/2, BRCA-related genes, ataxia telangiectasia mutated (ATM), and others. Here, we review the molecular consequences of targeted DDR inhibition, from tumor cell death to increased engagement of the anti-tumor immune response. Additionally, we discuss mechanistic and clinical rationale for pairing targeted DDRis with immunotherapy for enhanced tumor control. We also review biomarkers for patient selection and promising new immunotherapy approaches poised to form the foundation of next-generation DDRi and immunotherapy combinations.

Cancer-cell-intrinsic mechanisms shaping the immunosuppressive landscape of prostate cancer

Although immunotherapy has revolutionized cancer treatment and achieved remarkable success across many different cancer types, only a subset of patients shows meaningful clinical responses. In particular, advanced prostate cancer exhibits overwhelming de novo resistance to immune checkpoint blockade therapy. This is primarily due to the immunosuppressive tumor microenvironment of prostate cancer. Therefore, it is paramount to understand how prostate cancer cell-intrinsic mechanisms promote immune evasion and foster an immunosuppressive microenvironment. Here, we review recent findings that reveal the roles of the genetic alterations, androgen receptor signaling, cancer cell plasticity, and oncogenic pathways in shaping the immunosuppressive microenvironment and thereby driving immunotherapy resistance. Based on preclinical and clinical observations, a variety of therapeutic strategies are being developed that may illuminate new paths to enhance immunotherapy efficacy in prostate cancer.

At the crossroads of immunotherapy for oncogene-addicted subsets of NSCLC

Non-small-cell lung cancer (NSCLC) has become a paradigm of precision medicine, with the discovery of numerous disease subtypes defined by specific oncogenic driver mutations leading to the development of a range of molecularly targeted therapies. Over the past decade, rapid progress has also been made in the development of immune-checkpoint inhibitors (ICIs), especially antagonistic antibodies targeting the PD-L1-PD-1 axis, for the treatment of NSCLC. Although many of the major oncogenic drivers of NSCLC are associated with intrinsic resistance to ICIs, patients with certain oncogene-driven subtypes of the disease that are highly responsive to specific targeted therapies might also derive benefit from immunotherapy. However, the development of effective immunotherapy approaches for oncogene-addicted NSCLC has been challenged by a lack of predictive biomarkers for patient selection and limited knowledge of how ICIs and oncogene-directed targeted therapies should be combined. Therefore, whether ICIs alone or with chemotherapy or even in combination with molecularly targeted agents would offer comparable benefit in the context of selected oncogenic driver alterations to that observed in the general unselected NSCLC population remains an open question. In this Review, we discuss the effects of oncogenic driver mutations on the efficacy of ICIs and the immune tumour microenvironment as well as the potential vulnerabilities that could be exploited to overcome the challenges of immunotherapy for oncogene-addicted NSCLC.

Targets of Immune Escape Mechanisms in Cancer: Basis for Development and Evolution of Cancer Immune Checkpoint Inhibitors

Immune checkpoint blockade (ICB) has emerged as a novel therapeutic tool for cancer therapy in the last decade. Unfortunately, a small number of patients benefit from approved immune checkpoint inhibitors (ICIs). Therefore, multiple studies are being conducted to find new ICIs and combination strategies to improve the current ICIs. In this review, we discuss some approved immune checkpoints, such as PD-L1, PD-1, and CTLA-4, and also highlight newer emerging ICIs. For instance, HLA-E, overexpressed by tumor cells, represents an immune-suppressive feature by binding CD94/NKG2A, on NK and T cells. NKG2A blockade recruits CD8+ T cells and activates NK cells to decrease the tumor burden. NKG2D acts as an NK cell activating receptor that can also be a potential ICI. The adenosine A2A and A2B receptors, CD47-SIRPα, TIM-3, LAG-3, TIGIT, and VISTA are targets that also contribute to cancer immunoresistance and have been considered for clinical trials. Their antitumor immunosuppressive functions can be used to develop blocking antibodies. PARPs, mARTs, and B7-H3 are also other potential targets for immunosuppression. Additionally, miRNA, mRNA, and CRISPR-Cas9-mediated immunotherapeutic approaches are being investigated with great interest. Pre-clinical and clinical studies project these targets as potential immunotherapeutic candidates in different cancer types for their robust antitumor modulation.

Efficacy of immune checkpoint inhibitor monotherapy or combined with other small molecule-targeted agents in ovarian cancer

Ovarian cancer is the most lethal female reproductive system tumour. Despite the great advances in surgery and systemic chemotherapy over the past two decades, almost all patients in stages III and IV relapse and develop resistance to chemotherapy after first-line treatment. Ovarian cancer has an extraordinarily complex immunosuppressive tumour microenvironment in which immune checkpoints negatively regulate T cells activation and weaken antitumour immune responses by delivering immunosuppressive signals. Therefore, inhibition of immune checkpoints can break down the state of immunosuppression. Indeed, Immune checkpoint inhibitors (ICIs) have revolutionised the therapeutic landscape of many solid tumours. However, ICIs have yielded modest benefits in ovarian cancer. Therefore, a more comprehensive understanding of the mechanistic basis of the immune checkpoints is needed to improve the efficacy of ICIs in ovarian cancer. In this review, we systematically introduce the mechanisms and expression of immune checkpoints in ovarian cancer. Moreover, this review summarises recent updates regarding ICI monotherapy or combined with other small-molecule-targeted agents in ovarian cancer.

The Sesquiterpene Lactone-Rich Fraction of Inula helenium L. Enhances the Antitumor Effect of Anti-PD-1 Antibody in Colorectal Cancer: Integrative Phytochemical, Transcriptomic, and Experimental Analyses

Treatment strategies combining immune checkpoint inhibitors with sesquiterpene lactones have attracted much attention as a promising approach for cancer treatment. We systemically analyzed gene expression profiles of cells in response to two major sesquiterpene lactones, alantolactone and isoalantolactone, and determined whether the sesquiterpene lactone-rich fraction of Inula helenium L. (SFIH) enhances the antitumor effect of anti-PD-1 antibody in MC38 colorectal cancer-bearing mice. Gene expression and pathway analysis using RNA sequencing data were used to identify the SFIH-driven combined activity with anti-PD-1 antibody. The results showed that SFIH significantly enhanced the antitumor effect of anti-PD-1 antibody by reducing tumor growth and increasing the survival time of mice. Specifically, SFIH exhibited antitumor activity when combined with anti-PD-1 antibody, and the effects were further enhanced compared with monotherapy. An analysis of immune cells indicated that combination treatment with SFIH and anti-PD-1 antibody significantly increased the proportion of CD8⁺ T cells. Moreover, combination treatment enhanced antitumor immunity by decreasing the population of myeloid-derived suppressor cells and increasing the number of M1-like macrophages. Pathway enrichment analysis revealed that combination therapy activated immune-related pathways to a greater extent than monotherapy. In conclusion, our integrative analysis demonstrates that SFIH enhances the response of murine tumors to anti-PD-1 antibody. These findings provide insight into developing integrative therapeutics and molecular data for the use of natural products as an adjunct treatment for colorectal cancer.

Multiparameter single-cell proteomic technologies give new insights into the biology of ovarian tumors

High-grade serous ovarian cancer (HGSOC) is the most lethal gynecological malignancy. Its diagnosis at advanced stage compounded with its excessive genomic and cellular heterogeneity make curative treatment challenging. Two critical therapeutic challenges to overcome are carboplatin resistance and lack of response to immunotherapy. Carboplatin resistance results from diverse cell autonomous mechanisms which operate in different combinations within and across tumors. The lack of response to immunotherapy is highly likely to be related to an immunosuppressive HGSOC tumor microenvironment which overrides any clinical benefit. Results from a number of studies, mainly using transcriptomics, indicate that the immune tumor microenvironment (iTME) plays a role in carboplatin response. However, in patients receiving treatment, the exact mechanistic details are unclear. During the past decade, multiplex single-cell proteomic technologies have come to the forefront of biomedical research. Mass cytometry or cytometry by time-of-flight, measures up to 60 parameters in single cells that are in suspension. Multiplex cellular imaging technologies allow simultaneous measurement of up to 60 proteins in single cells with spatial resolution and interrogation of cell-cell interactions. This review suggests that functional interplay between cell autonomous responses to carboplatin and the HGSOC immune tumor microenvironment could be clarified through the application of multiplex single-cell proteomic technologies. We conclude that for better clinical care, multiplex single-cell proteomic technologies could be an integral component of multimodal biomarker development that also includes genomics and radiomics. Collection of matched samples from patients before and on treatment will be critical to the success of these efforts.

Combining PARP Inhibition and Immunotherapy in BRCA-Associated Cancers

Poly (ADP-ribose) polymerase (PARP) inhibitors have significantly improved treatment outcomes of homologous recombination (HR) repair-deficient cancers. While the activity of these agents is largely linked to multiple mechanisms underlying the synthetic lethality of PARP inhibition and HR deficiency, emerging data suggest that their efficacy is also tied to their effects on the immune microenvironment and dependent upon cytotoxic T-cell activation. Effects observed in preclinical models are currently being validated in on-treatment biopsy samples procured from patients enrolled in clinical trials. Although this work has stimulated the development of combinations of PARP inhibitors with immunomodulatory agents, results to date have not demonstrated the superiority of combined PARP inhibition and immune checkpoint blockade compared with PARP inhibition alone. These results have stimulated a more comprehensive assessment of the immunosuppressive components of the tumor microenvironment that must be addressed so that the efficacy of PARP inhibitor agents can be maximized.