Regorafenib enhances antitumor immunity via inhibition of p38 kinase/Creb1/Klf4 axis in tumor-associated macrophages

Underlying mechanisms and management strategies for regorafenib-induced toxicity in hepatocellular carcinoma

INTRODUCTION

Hepatocellular carcinoma (HCC) accounts for 85% of liver cancer cases and is the third leading cause of cancer death. Regorafenib is a multi-target inhibitor that dramatically prolongs progression-free survival in HCC patients who have failed sorafenib therapy. However, one of the primary factors limiting regorafenib's clinical utilization is toxicity. Using Clinical Trials.gov and PubMed, we gathered clinical data on regorafenib and conducted a extensive analysis of the medication's adverse reactions and mechanisms. Next, we suggested suitable management techniques to improve regorafenib's effectiveness.

AREAS COVERED

We have reviewed the mechanisms by which regorafenib-induced toxicity occurs and general management strategies through clinical trials of regorafenib. Furthermore, by examining the literature on regorafenib and other tyrosine kinase inhibition, we summarized the mechanics of the onset of regorafenib toxicity and mechanism-based intervention strategies by reviewing the literature related to regorafenib and other tyrosine kinase inhibition.

EXPERT OPINION

One of the primary factors restricting regorafenib's clinical utilization and combination therapy is its toxicity reactions. To optimize regorafenib treatment regimens, it is especially important to further understand the specific toxicity mechanisms of regorafenib as a multi-kinase inhibitor.

Proteomic analysis of peripheral blood mononuclear cells from OSCC patients reveals potential immune checkpoints to enable personalized treatment

Oral squamous cell carcinoma (OSCC) is one of the most prevalent cancers worldwide, with high mortality and prevalence rates. OSCC is defined as an immunogenic tumor with the potential to be recognized and targeted by the immune system. It is characterized by the extensive infiltration of immune cells and plays a vital role in tumorigenesis. Peripheral blood mononuclear cells (PBMC) are a functional subset of immune cells readily accessible through minimally invasive procedures. The molecular characterization of immune cells aids in understanding their functional roles in various pathophysiological conditions. Proteomic analysis of PBMCs from cancer patients provides insight into the mechanism of immunoregulation and the role of immune cells in impeding tumor development and progression. Therefore, the present study investigated the immune cell proteome of a cancer control cohort within OSCC, leveraging data-independent acquisition analysis by mass spectrometry (DIA-MS). Among the differentially abundant proteins in OSCC, we identified promising molecular targets, including LMNB1, CTSB, CD14, CD177, and SPI1. Further exploration of the signaling pathways related to the candidate molecules demonstrated their involvement in cancer immunomodulation. Therefore, this study can serve as a platform for identifying new candidate proteins to further investigate their potential as immunotherapeutic targets and prognostic markers.

Regorafenib Attenuates Osteoclasts Differentiation by Inhibiting the NF-κB, NFAT, ERK, and p38 Signaling Pathways

Osteolytic diseases such as osteoporosis and neoplastic bone metastases are caused by the excessive activation of osteoclasts. Inhibiting the excessive activation of osteoclasts is a crucial strategy for treating osteolytic diseases. This study investigated the roles and mechanisms of regorafenib, a tyrosine kinase inhibitor, on osteoclasts and osteolytic diseases. We first identified the potential targets and mechanisms of regorafenib on osteoclast-related osteolytic diseases using network pharmacological analysis and molecular docking techniques. Then, we verified its role and mechanism on osteoclasts via cellular and animal experiments. Network pharmacology analysis identified 89 common targets shared by regorafenib and osteoclast-related osteolytic diseases. Enrichment analysis suggested that regorafenib may act on osteoclast-related osteolytic diseases by modulating targets such as AKT1, CASP3, MMP9, and MAPK3, regulating biological processes such as cell proliferation, apoptosis, and phosphorylation regulation, and influencing signaling pathways such as MAPK, PI3K/AKT, and osteoclast differentiation. The molecular docking results indicated that regorafenib and AKT1, CASP3, MMP9, MAPK3, and MAPK14 were stably docked. Cell experiments demonstrated that regorafenib significantly inhibited osteoclast differentiation and bone resorption in RAW 264.7 cells and bone marrow macrophages in a dose-dependent manner, with up to 50% reduction at 800 nM concentration without exhibiting cytotoxic effects. Furthermore, Western blot and RT-qPCR results demonstrated that regorafenib inhibited osteoclast differentiation by blocking the transduction of RANKL-induced NF-κB, p38, ERK, and NFAT signaling pathways. In vivo studies using an ovariectomized mouse model showed that regorafenib significantly improved bone volume fraction (BV/TV), bone surface to total volume (BS/TV), and number of trabeculae (TB.N), as well as reduced trabecular separation (Tb.Sp) compared to the OVX groups (P < 0.05). TRAcP staining results revealed a reduction in the number of osteoclasts with regorafenib treatment (P < 0.01). These results indicate that regorafenib exerts its protective effects against osteoclast-related osteolytic disease by inhibiting the RANKL-induced NF-κB, NFAT, ERK, and p38 signaling pathways. This study proves that regorafenib may serve as a potential therapeutic agent for osteoclast-related osteolytic diseases.

KLF4 Induces Colorectal Cancer by Promoting EMT via STAT3 Activation

OBJECTIVE

Krüppel-like factor 4 (KLF4) has been demonstrated to exert a pro-carcinogenic effect in solid tissues. However, the precise biological function and underlying mechanisms in colorectal cancer (CRC) remains elucidated.

AIMS

To investigate whether KLF4 participates in the proliferation and invasion of CRC.

METHODS

The expression of KLF4 was investigated using immunohistochemistry and immunoblotting. The clinical significance of KLF4 was evaluated. Furthermore, the effect of inhibiting or overexpressing KLF4 on tumor was examined. Immunoblotting and qPCR were used to detect Epithelial-mesenchymal transition-related proteins levels. Additionally, the molecular function of KLF4 is related to the STAT3 signaling pathway and was determined through JASPAR, GSEA analysis, and in vitro experiments.

RESULTS

KLF4 exhibits down-regulated expression in CRC and is part of the vessel invasion, TNM stage, and worse prognosis. In vitro studies have shown that KLF4 promotes cellular proliferation and invasion, as well as EMT processes. Xenograft tumor models confirmed the oncogenic role of KLF4 in nude mice. Furthermore, GSEA and JASPAR databases analysis reveal that the binding of KLF4 to the signal transducer and activator of transcription 3 (STAT3) promoter site induces activation of p-STAT3 signaling. Subsequent targeting of STAT3 confirmed its pivotal role in mediating the oncogenic effects exerted by KLF4.

CONCLUSION

The study suggests that KLF4 activates STAT3 signaling, inducing epithelial-mesenchymal transition, thereby promoting CRC progression.

Liquidambaric acid inhibits the proliferation of hepatocellular carcinoma cells by targeting PPARα-RXRα to down-regulate fatty acid metabolism

Hepatocellular carcinoma (HCC) is a primary malignant tumor of the liver. As the global obesity rate rises, non-alcoholic fatty liver disease (NAFLD) has emerged as the most rapidly increasing cause of HCC. Consequently, the regulation of lipid metabolism has become a crucial target for the prevention and treatment of HCC. Liquidambaric acid (LDA), a pentacyclic triterpenoid compound derived from various plants, exhibits diverse biological activities. We found that LDA could inhibit HCC cell proliferation by arresting cell cycle and prompting apoptosis. Additionally, LDA can augment the therapeutic efficacy of Regorafenib in HCC in vitro and vivo. Our study utilized transcriptome analysis, luciferase reporter assays, and co-immunocoprecipitation experiments to elucidate the anti-HCC mechanism of LDA. We discovered that LDA disrupts the formation of the PPARα-RXRα heterodimer, leading to the down-regulation of the ACSL4 gene and subsequently impacting the fatty acid metabolism of HCC cells, ultimately inhibiting HCC proliferation. Our research contributes to the identification of novel therapeutic agents and targets for the treatment of HCC.

Biological impact and therapeutic implication of tumor-associated macrophages in hepatocellular carcinoma

The tumor microenvironment is a complex space comprised of normal, cancer and immune cells. The macrophages are considered as the most abundant immune cells in tumor microenvironment and their function in tumorigenesis is interesting. Macrophages can be present as M1 and M2 polarization that show anti-cancer and oncogenic activities, respectively. Tumor-associated macrophages (TAMs) mainly have M2 polarization and they increase tumorigenesis due to secretion of factors, cytokines and affecting molecular pathways. Hepatocellular carcinoma (HCC) is among predominant tumors of liver that in spite of understanding its pathogenesis, the role of tumor microenvironment in its progression still requires more attention. The presence of TAMs in HCC causes an increase in growth and invasion of HCC cells and one of the reasons is induction of glycolysis that such metabolic reprogramming makes HCC distinct from normal cells and promotes its malignancy. Since M2 polarization of TAMs stimulates tumorigenesis in HCC, molecular networks regulating M2 to M1 conversion have been highlighted and moreover, drugs and compounds with the ability of targeting TAMs and suppressing their M2 phenotypes or at least their tumorigenesis activity have been utilized. TAMs increase aggressive behavior and biological functions of HCC cells that can result in development of therapy resistance. Macrophages can provide cell-cell communication in HCC by secreting exosomes having various types of biomolecules that transfer among cells and change their activity. Finally, non-coding RNA transcripts can mainly affect polarization of TAMs in HCC.

Combination of dual JAK/HDAC inhibitor with regorafenib synergistically reduces tumor growth, metastasis, and regorafenib-induced toxicity in colorectal cancer

BACKGROUND

Treatment with regorafenib, a multiple-kinase inhibitor, to manage metastatic colorectal cancers (mCRCs) shows a modest improvement in overall survival but is associated with severe toxicities. Thus, to reduce regorafenib-induced toxicity, we used regorafenib at low concentration along with a dual JAK/HDAC small-molecule inhibitor (JAK/HDACi) to leverage the advantages of both JAK and HDAC inhibition to enhance antitumor activity. The therapeutic efficacy and safety of the combination treatment was evaluated with CRC models.

METHODS

The cytotoxicity of JAK/HDACi, regorafenib, and their combination were tested with normal colonic and CRC cells exhibiting various genetic backgrounds. Kinomic, ATAC-seq, RNA-seq, cell cycle, and apoptosis analyses were performed to evaluate the cellular functions/molecular alterations affected by the combination. Efficacy of the combination was assessed using patient-derived xenograft (PDX) and experimental metastasis models of CRC. To evaluate the interplay between tumor, its microenvironment, and modulation of immune response, MC38 syngeneic mice were utilized.

RESULTS

The combination therapy decreased cell viability; phosphorylation of JAKs, STAT3, EGFR, and other key kinases; and inhibited deacetylation of histone H3K9, H4K8, and alpha tubulin proteins. It induced cell cycle arrest at G0-G1 phase and apoptosis of CRC cells. Whole transcriptomic analysis showed that combination treatment modulated molecules involved in apoptosis, extracellular matrix-receptor interaction, and focal adhesion pathways. It synergistically reduces PDX tumor growth and experimental metastasis, and, in a syngeneic mouse model, the treatment enhances the antitumor immune response as evidenced by higher infiltration of CD45 and cytotoxic cells. Pharmacokinetic studies showed that combination increased the bioavailability of regorafenib.

CONCLUSIONS

The combination treatment was more effective than with regorafenib or JAK/HDACi alone, and had minimal toxicity. A clinical trial to evaluate this combination for treatment of mCRCs is warranted.

Tramadol suppresses growth of orthotopic liver tumors via promoting M1 macrophage polarization in the tumor microenvironment

Tumor-associated macrophages (TAMs) are major infiltrating immune cells in liver cancer. They are polarized to anti-tumor M1 type or tumor-supporting M2 type in a dynamic changing state. Tramadol, a synthetic opioid, exhibits tumor-suppressing effect in several cancers, but whether it plays a role in TAMs polarization is uncertain. In the present study, the potential influence of tramadol on TAMs polarization was explored in liver cancer. An orthotopic murine Hepa 1-6 liver cancer model was constructed. The potential function of tramadol was evaluated by cell viability assay, EdU incorporation assay, flow cytometry, immunofluorescence, quantitative real-time polymerase chain reaction (qRT-PCR), enzyme-linked immunosorbent assay (ELISA) assay, T cell proliferation and suppression assays and western blot. We found that tramadol suppressed proliferation and tumor formation of murine Hepa 1-6 cells in vitro and in vivo. Tramadol reprogramed the immune microenvironment to favor M1 macrophage polarization in orthotopic Hepa 1-6 tumors. Moreover, tramadol facilitated M1 macrophage polarization and inhibited M2 macrophage polarization of bone marrow-derived macrophages (BMDMs) and human THP-1 macrophages in vitro. Furthermore, tramadol-treated BMDMs promoted proliferation and activation of splenic CD4+ and CD8+ T cells. Tramadol induced cellular ROS production and mitochondrial dysfunction of BMDMs. Finally, tramadol activated NF-κB signaling in BMDMs and THP-1 macrophages, while inhibition of NF-κB signaling by JSH-23 attenuated the influence of tramadol on macrophage polarization. In conclusion, these data elucidated a novel anti-tumor mechanism of tramadol in liver cancer. Tramadol might be a promising treatment strategy for liver cancer patients.

Antiangiogenic-immune-checkpoint inhibitor combinations: lessons from phase III clinical trials

Antiangiogenic agents, generally antibodies or tyrosine-kinase inhibitors that target the VEGF-VEGFR pathway, are currently among the few combination partners clinically proven to improve the efficacy of immune-checkpoint inhibitors (ICIs). This benefit has been demonstrated in pivotal phase III trials across different cancer types, some with practice-changing results; however, numerous phase III trials have also had negative results. The rationale for using antiangiogenic drugs as partners for ICIs relies primarily on blocking the multiple immunosuppressive effects of VEGF and inducing several different vascular-modulating effects that can stimulate immunity, such as vascular normalization leading to increased intratumoural blood perfusion and flow, and inhibition of pro-apoptotic effects of endothelial cells on T cells, among others. Conversely, VEGF blockade can also cause changes that suppress antitumour immunity, such as increased tumour hypoxia, and reduced intratumoural ingress of co-administered ICIs. As a result, the net clinical benefits from antiangiogenic-ICI combinations will be determined by the balance between the opposing effects of VEGF signalling and its inhibition on the antitumour immune response. In this Perspective, we summarize the results from the currently completed phase III trials evaluating antiangiogenic agent-ICI combinations. We also discuss strategies to improve the efficacy of these combinations, focusing on aspects that include the deleterious functions of VEGF-VEGFR inhibition on antitumour immunity, vessel co-option as a driver of non-angiogenic tumour growth, clinical trial design, or the rationale for drug selection, dosing and scheduling.

Allosteric SHP2 inhibition enhances regorafenib's effectiveness in colorectal cancer treatment

Colorectal cancer (CRC) is the third most common cancer globally. Regorafenib, a multi-target kinase inhibitor, has been approved for treating metastatic colorectal cancer patients who have undergone at least two prior standard anti-cancer therapies. However, regorafenib efficacy as a single agent remains suboptimal. A promising target at the crossroads of multiple signaling pathways is the Src homology 2 domain-containing protein tyrosine phosphatase (SHP2). However, a combination approach using SHP2 inhibitors (SHP099) and anti-angiogenic drugs (Regorafenib) has not been reported in current research. In this study, we conducted in vitro experiments combining SHP099 and regorafenib and established an MC-38 colon cancer allograft mouse model. Our results revealed that co-treatment with SHP099 and regorafenib significantly inhibited cell viability and altered the biological characteristics of tumor cells compared with treatment alone in vitro. Furthermore, the combination strategy demonstrated superior therapeutic efficacy compared to monotherapy with either drug. This was evidenced by reduced tumor size, decreased proliferation, increased apoptosis, normalized tumor microvasculature, and improved antitumor immune response in vivo. These findings suggest that the combination of an SHP2 inhibitor and regorafenib is a promising therapeutic approach for patients with colorectal cancer.

Molecular insight into T cell exhaustion in hepatocellular carcinoma

Hepatocellular carcinoma is one of the leading causes of cancer-related mortality globally. The emergence of immunotherapy has been shown to be a promising therapeutic approach for hepatocellular carcinoma in recent years. It has been well known that T cell plays a key role in current immunotherapy. However, sustained exposure to antigenic stimulation within the tumor microenvironment may lead to T cell exhaustion, which may cause treatment ineffectiveness. Therefore, reversing T cell exhaustion has been an important issue for the clinical application of immunotherapy, and a comprehensive understanding of the intricacies surrounding T cell exhaustion and its underlying mechanisms is imperative for devising strategies to overcome the T cell exhaustion during treatment. In this review, we summarized the reported drivers of T cell exhaustion in hepatocellular carcinoma and delineate potential ways to reverse it. Additionally, we discussed the interplay among metabolic plasticity, epigenetic regulation, and transcriptional factors in exhausted T cells in hepatocellular carcinoma, and their implication for future clinical applications.

A method for predicting drugs that can boost the efficacy of immune checkpoint blockade

Combination therapy is a promising therapeutic strategy to enhance the efficacy of immune checkpoint blockade (ICB); however, predicting drugs for effective combination is challenging. Here we developed a general data-driven method called CM-Drug for screening compounds that can boost ICB treatment efficacy based on core and minor gene sets identified between responsive and nonresponsive samples in ICB therapy. The CM-Drug method was validated using melanoma and lung cancer mouse models, with combined therapeutic efficacy demonstrated in eight of nine predicted compounds. Among these compounds, taltirelin had the strongest synergistic effect. Mechanistic analysis and experimental verification demonstrated that taltirelin can stimulate CD8+ T cells and is mediated by the induction of thyroid-stimulating hormone. This study provides an effective and general method for predicting and evaluating drugs for combination therapy and identifies candidate compounds for future ICB combination therapy.

Hyperammonemic encephalopathy after tyrosine kinase inhibitors: A literature review and a case example

OBJECTIVE

To review the evidence of uncommon but fatal adverse event of hyperammonemic encephalopathy by tyrosine kinase inhibitors (TKI) and the possible mechanisms underlying this condition and to describe the case of a patient that developed drug-induced hyperammonemic encephalopathy related to TKI.

DATA SOURCES

Literature search of different databases was performed for studies published from 1 January 1992 to 7 May 2023. The search terms utilized were hyperammonemic encephalopathy, TKI, apatinib, pazopanib, sunitinib, imatinib, sorafenib, regorafenib, trametinib, urea cycle regulation, sorafenib, carbamoyl-phosphate synthetase 1, ornithine transcarbamylase, argininosuccinate synthetase, argininosuccinate lyase, arginase 1, Mitogen activated protein kinases (MAPK) pathway and mTOR pathway, were used individually search or combined.

DATA SUMMARY

Thirty-seven articles were included. The articles primarily focused in hyperammonemic encephalopathy case reports, management of hyperammonemic encephalopathy, urea cycle regulation, autophagy, mTOR and MAPK pathways, and TKI.

CONCLUSION

Eighteen cases of hyperammonemic encephalopathy were reported in the literature from various multitargeted TKI. The mechanism of this event is not well-understood but some authors have hypothesized vascular causes since some of TKI are antiangiogenic, however our literature review shows a possible relationship between the urea cycle and the molecular inhibition exerted by TKI. More preclinical evidence is required to unveil the biochemical mechanisms responsible involved in this process and clinical studies are necessary to shed light on the prevalence, risk factors, management and prevention of this adverse event. It is important to monitor neurological symptoms and to measure ammonia levels when manifestations are detected.

Inhibition of RhoGEF/RhoA alleviates regorafenib resistance and cancer stemness via Hippo signaling pathway in hepatocellular carcinoma

Patients with hepatocellular carcinoma (HCC) are vulnerable to drug resistance. Although drug resistance has been taken much attention to HCC therapy, little is known of regorafenib and regorafenib resistance (RR). This study aimed to determine the drug resistance pattern and the role of RhoA in RR. Two regorafenib-resistant cell lines were constructed based on Huh7 and Hep3B cell lines. In vitro and in vivo assays were conducted to study RhoA expression, the activity of Hippo signaling pathway and cancer stem cell (CSC) traits. The data showed that RhoA was highly expressed, Hippo signaling was hypoactivated and CSC traits were more prominent in RR cells. Inhibiting RhoA could reverse RR, and the alliance of RhoA inhibition and regorafenib synergistically attenuated CSC phenotype. Furthermore, inhibiting LARG/RhoA increased Kibra/NF2 complex formation, prevented YAP from shuttling into the nucleus and repressed CD44 mRNA expression. Clinically, the high expression of RhoA correlated with poor prognosis. LARG, RhoA, YAP1 and CD44 show positive correlation with each other. Thus, inhibition of RhoGEF/RhoA has the potential to reverse RR and repress CSC phenotype in HCC.

Regorafenib plus nivolumab in unresectable hepatocellular carcinoma: the phase 2 RENOBATE trial

Regorafenib has anti-tumor activity in patients with unresectable hepatocellular carcinoma (uHCC) with potential immunomodulatory effects, suggesting that its combination with immune checkpoint inhibitor may have clinically meaningful benefits in patients with uHCC. The multicenter, single-arm, phase 2 RENOBATE trial tested regorafenib-nivolumab as front-line treatment for uHCC. Forty-two patients received nivolumab 480 mg every 4 weeks and regorafenib 80 mg daily (3-weeks-on/1-week-off schedule). The primary endpoint was the investigator-assessed objective response rate (ORR) per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. The secondary endpoints included safety, progression-free survival (PFS) and overall survival (OS). ORR per RECIST version 1.1 was 31.0%, meeting the primary endpoint. The most common adverse events were palmar-plantar erythrodysesthesia syndrome (38.1%), alopecia (26.2%) and skin rash (23.8%). Median PFS was 7.38 months. The 1-year OS rate was 80.5%, and the median OS was not reached. Exploratory single-cell RNA sequencing analyses of peripheral blood mononuclear cells showed that long-term responders exhibited T cell receptor repertoire diversification, enrichment of genes representing immunotherapy responsiveness in MKI67+ proliferating CD8+ T cells and a higher probability of M1-directed monocyte polarization. Our data support further clinical development of the regorafenib-nivolumab combination as front-line treatment for uHCC and provide preliminary insights on immune biomarkers of response. ClinicalTrials.gov identifier: NCT04310709 .

TPX2 influences the regulation of macrophage polarization via the NF-κB pathway in lung adenocarcinoma

BACKGROUND

Lung adenocarcinoma (LUAD) is the most prevalent subtype of lung cancer. Xklp2 targeting protein (TPX2), a crucial oncogene exhibits high expression levels in various cancers including LUAD, may serve as a potential target for clinical intervention. Additionally, the growth of lung cancer is significantly influenced by the tumor microenvironment (TME). However, there have been no reports on experiments investigating TPX2 in tumor-infiltrating immune cells (TIICs) in LUAD. Therefore, we verified the effect of TPX2 on macrophage polarization both in vitro and in vivo.

METHODS

We silenced TPX2 the gene in A549 cells and collected supernatants for macrophage culture. We then used flow cytometry and Western blot analysis to assess macrophage polarization. Additionally, we verified the expression of macrophage colony-stimulating factor (M-CSF), and CD163 by immunohistochemistry (IHC) in tissue specimens from LUAD patients. Finally, pathways related to TPX2's regulatory function in macrophage polarization were analyzed through whole genome sequencing, Western blotting, and immunofluorescence (IF).

RESULTS

Silencing TPX2 can affect the ratio of CD80+ M1/CD163+ M2 and reduce the polarization of M0 macrophages to CD163+ M2 macrophages mainly by inhibiting the expression of M-CSF. In human LUAD tissues, the expression levels of TPX2, M-CSF and CD163 increased with the degree of differentiation. Silencing TPX2 inhibits the NF-κB signaling pathway, thereby reducing the expression of M-CSF, and affecting macrophage polarization.

CONCLUSION

Silencing TPX2 can inhibit the expression of M-CSF by blocking the NF-κB signal, thereby reducing CD163+ M2 macrophage polarization. The TPX2/NF-κB/M-CSF signaling axis may be involved in regulating macrophage polarization.

Translational research on drug development and biomarker discovery for hepatocellular carcinoma

Translational research plays a key role in drug development and biomarker discovery for hepatocellular carcinoma (HCC). However, unique challenges exist in this field because of the limited availability of human tumor samples from surgery, the lack of homogenous oncogenic driver mutations, and the paucity of adequate experimental models. In this review, we provide insights into these challenges and review recent advancements, with a particular focus on the two main agents currently used as mainstream therapies for HCC: anti-angiogenic agents and immunotherapy. First, we examine the pre-clinical and clinical studies to highlight the challenges of determining the optimal therapeutic combinations with biologically effective dosage for HCC. Second, we discuss biomarker studies focusing on anti-PD1/anti-PD-L1-based combination therapy. Finally, we discuss the progress made in our collective understanding of tumor immunology and in multi-omics analysis technology, which enhance our understanding of the mechanisms underlying immunotherapy, characterize different patient subgroups, and facilitate the development of novel combination approaches to improve treatment efficacy. In summary, this review provides a comprehensive overview of efforts in translational research aiming at advancing our understanding of and improving the treatment of HCC.

The immune response of hepatocellular carcinoma after locoregional and systemic therapies: The available combination option for immunotherapy

Hepatocellular carcinoma (HCC) is associated with a highly heterogeneous immune environment that produces an immune response to various locoregional treatments (LRTs), which in turn affects the effectiveness of immunotherapy. Although LRTs still dominate HCC therapies, 50-60% of patients will ultimately be treated with systemic therapies and might receive those treatments for the rest of their life. TACE, SIRT, and thermal ablation can dramatically increase the immunosuppressive state of HCC, a condition that can be addressed by combination with immunotherapy to restore the activity of lymphocytes and the secretion of cellular immune factors. Immune treatment with locoregional and systemic treatments has dramatically changed the management of HCC. In this review, we examine the research on the changes in the immune microenvironment after locoregional or systemic treatment. We also summarize the regulation of various immune cells and immune factors in the tumor microenvironment and discuss the different infiltration degrees of immune cells and factors on the prognosis of HCC to better compare the efficacy between different treatment methods from the perspective of the tumor microenvironment. This information can be used to help develop treatment options for the upcoming new era of HCC treatment in the future.

Time-resolved single-cell transcriptomics defines immune trajectories in glioblastoma

Deciphering the cell-state transitions underlying immune adaptation across time is fundamental for advancing biology. Empirical in vivo genomic technologies that capture cellular dynamics are currently lacking. We present Zman-seq, a single-cell technology recording transcriptomic dynamics across time by introducing time stamps into circulating immune cells, tracking them in tissues for days. Applying Zman-seq resolved cell-state and molecular trajectories of the dysfunctional immune microenvironment in glioblastoma. Within 24 hours of tumor infiltration, cytotoxic natural killer cells transitioned to a dysfunctional program regulated by TGFB1 signaling. Infiltrating monocytes differentiated into immunosuppressive macrophages, characterized by the upregulation of suppressive myeloid checkpoints Trem2, Il18bp, and Arg1, over 36 to 48 hours. Treatment with an antagonistic anti-TREM2 antibody reshaped the tumor microenvironment by redirecting the monocyte trajectory toward pro-inflammatory macrophages. Zman-seq is a broadly applicable technology, enabling empirical measurements of differentiation trajectories, which can enhance the development of more efficacious immunotherapies.

Regorafenib monotherapy or combined with an immune-checkpoint inhibitor as later-line treatment for metastatic colorectal cancer: a multicenter, real-world retrospective study in China

OBJECTIVE

To evaluate the efficacy and safety of regorafenib monotherapy or in combination with immune-checkpoint inhibitor while treating Chinese patients with metastatic colorectal cancer (mCRC): a real-world study.

METHODS

The data of patients with metastatic colorectal cancer who received regorafenib-containing regimen as the third or later line treatment at ten Chinese hospitals from Aug 2017 to Jun 2020 were retrospectively analyzed, including dosing details, survival data as well as adverse events. Survival analysis was further performed for patients administrated with regorafenib monotherapy and combined with an immune-checkpoint inhibitor based on Kaplan-Meier and Cox regression methods. The primary endpoint was overall survival.

RESULTS

A total of 537 patients were included with a median age of 61, among whom 376 received regorafenib monotherapy and 245 received regorafenib combined with immune-checkpoint inhibitors. The clinicopathological characteristics of the two groups at baseline were mainly balanced. No significant difference in progression-free survival (PFS) was observed in patients receiving regorafenib monotherapy or combination therapy (3.8 vs. 5.5 months, p = 0.170). In contrast, patients receiving combination therapy had a more prolonged overall survival (OS) than those receiving regorafenib monotherapy (13.5 vs. 10.0 months, p = 0.001). The treatment regimen and regorafenib dosage were significant prognostic factors in the multivariate analysis. Significant benefits in PFS and OS were achieved in KRAS mutant and anti-angiogenesis treatment-naïve subgroups receiving combination therapy compared to monotherapy. No apparent increase was recorded in treatment-related adverse events in patients receiving combination therapy.

CONCLUSION

Regorafenib plus an immune-checkpoint inhibitor has already been a widely adopted strategy in the later-line treatment for mCRC in the real world. The combination therapy yielded a significantly prolonged overall survival than regorafenib alone, with a manageable safety profile in Chinese patients, and warrants further investigation.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04835324. Registered 6th April 2021.

A Systematic Review of Treatment-Related Adverse Events for Combination Therapy of Multiple Tyrosine Kinase Inhibitor and Immune Checkpoint Inhibitor

BACKGROUND

Combination therapy with multiple tyrosine kinase inhibitors (multi-TKIs) and immune checkpoint inhibitors (ICIs) has been increasingly tested in clinical studies. This study aimed to investigate the effect of the addition of ICI to multi-TKIs on the profile of treatment-related adverse events.

METHODS

An electronic database search was performed using PubMed and Web of Science to identify published clinical studies on multi-TKI monotherapy and multi-TKI plus ICI combination therapy from July 20, 2005 to July 1, 2023. The incidence rate of common adverse events caused by multi-TKI monotherapy and multi-TKI plus ICI combination therapy was obtained and compared from the viewpoints of (1) relative risk for the combination therapy vs sunitinib, (2) adverse event incidence rate by clinical trial, and (3) pooled incidence rate. The quality of the evidence was assessed with the Cochrane risk of bias tool. Meta-analysis used random effects models.

RESULTS

This systematic review identified 83 clinical studies involving 7951 patients. The combination therapy of multi-TKI and ICI was associated with an increased risk of diarrhea (relative risk [RR]: 1.24, 95% confidence interval [CI]: 1.15-1.33, P < .001), hypothyroidism (RR: 1.44, 95% CI: 1.11-1.87, P = .0064) and rash (RR: 1.71, 95% CI: 1.18-2.47, P = .0045) compared with multi-TKI monotherapy. The addition of ICI was suggested to decrease the risk of adverse events related to performance status.

CONCLUSION

Our study identified an increased risk of treatment-related adverse events associated with multi-TKI plus ICI combination therapy. This would help optimize the management of toxicities caused by multi-TKI plus ICI combination therapy.

Immunotherapy strategies and traditional Chinese medicine treatment for microsatellite stable metastatic colorectal cancer

The incidence and mortality of colorectal cancer (CRC) have increased year by year. In addition to traditional radiotherapy, chemotherapy, and targeted therapy, immunotherapy also brings hope to more patients with metastatic colorectal cancer (mCRC). However, these treatments are limited to patients with high microsatellite instability, and about 95% of mCRC patients with microsatellite stability (MSS) can not benefit from them. How to enhance the response of MSS mCRC patients to immunotherapy is the focus of current research. In recent years, it has been found that immunotherapy strategies are expected to improve the clinical efficacy for such patients, and the research reports of TCM combined with immunotherapy are increasing day by day. Therefore, this article aims to review the immunotherapy and traditional Chinese medicine treatment for MSS colorectal cancer.

PD-1 and PD-L1 inhibitors in cold colorectal cancer: challenges and strategies

Colorectal cancer (CRC) is the second most common cause of cancer mortality, with mismatch repair proficient (pMMR) and/or microsatellite stable (MSS) CRC making up more than 80% of metastatic CRC. Programmed death-ligand 1 (PD-L1) and programmed death 1 (PD-1) immune checkpoint inhibitors (ICIs) are approved as monotherapy in many cancers including a subset of advanced or metastatic colorectal cancer (CRC) with deficiency in mismatch repair (dMMR) and/or high microsatellite instability (MSI-H). However, proficient mismatch repair and microsatellite stable (pMMR/MSS) cold CRCs have not shown clinical response to ICIs alone. To potentiate the anti-tumor response of PD-L1/PD-1 inhibitors in patients with MSS cold cancer, combination strategies currently being investigated include dual ICI, and PD-L1/PD-1 inhibitors in combination with chemotherapy, radiotherapy, vascular endothelial growth factor (VEGF) /VEGF receptor (VEGFR) inhibitors, mitogen-activated protein kinase (MEK) inhibitors, and signal transducer and activation of transcription 3 (STAT3) inhibitors. This paper will review the mechanisms of PD-1/PD-L1 ICI resistance in pMMR/MSS CRC and potential combination strategies to overcome this resistance, summarize the published clinical experience with different combination therapies, and make recommendations for future avenues of research.

Macrophage metabolism, phenotype, function, and therapy in hepatocellular carcinoma (HCC)

The pivotal role of the tumor microenvironment (TME) in the initiation and advancement of hepatocellular carcinoma (HCC) is widely acknowledged, as it fosters the proliferation and metastasis of HCC cells. Within the intricate TME of HCC, tumor-associated macrophages (TAMs) represent a significant constituent of non-malignant cells. TAMs engage in direct communication with cancer cells in HCC, while also exerting influence on other immune cells to adopt a tumor-supportive phenotype that facilitates tumor progression. Among the multifaceted mechanisms at play, the metabolic reprogramming of both tumor cells and macrophages leads to phenotypic alterations and functional modifications in macrophages. This comprehensive review elucidates the intricate interplay between cellular metabolism and macrophage phenotype/polarization, while also providing an overview of the associated signaling molecules and potential therapeutic strategies for HCC.

The Role of Macrophages in Sarcoma Tumor Microenvironment and Treatment

Sarcomas are a heterogeneous group of malignant mesenchymal tumors, including soft tissue and bone sarcomas. Macrophages in the tumor microenvironment, involved in immunosuppression and leading to tumor development, are called tumor-associated macrophages (TAMs). TAMs are very important in modulating the microenvironment of sarcomas by expressing specific markers and secreting factors that influence immune and tumor cells. They are involved in many signaling pathways, such as p-STAT3/p-Erk1/2, PI3K/Akt, JAK/MAPK, and JAK/STAT3. TAMs also significantly impact the clinical outcomes of patients suffering from sarcomas and are mainly related to poor overall survival rates among bone and soft tissue sarcomas, for example, chondrosarcoma, osteosarcoma, liposarcoma, synovial sarcoma, and undifferentiated pleomorphic sarcoma. This review summarizes the current knowledge on TAMs in sarcomas, focusing on specific markers on sarcoma cells, cell-cell interactions, and the possibly involved molecular pathways. Furthermore, we discuss the clinical significance of macrophages in sarcomas as a potential target for new therapies, presenting clinical relevance, possible new treatment options, and ongoing clinical trials using TAMs in sarcoma treatment.

Sequencing Systemic Therapy in Hepatocellular Carcinoma

OPINION STATEMENT

Multiple treatment options are now approved for unresectable hepatocellular carcinoma (HCC). An immune checkpoint inhibitor (ICI)-containing regimen should be highly considered as the first-line treatment when there is no contraindication, especially in those with hepatitis virus-related HCC, due to proven superior overall survival (OS) compared to sorafenib. Atezolizumab plus bevacizumab and durvalumab plus tremelimumab remain the treatment of choice among all ICI-containing regimens, unless contraindications to either of the medications exist. Although sorafenib is still the only medication currently approved for select patients with Child-Pugh B (CP) HCC in the first-line setting, atezolizumab plus bevacizumab is being studied in this patient population. Moreover, patients with post-liver transplantation recurrence may benefit from tyrosine kinase inhibitors (TKIs), while more studies are still needed to determine the safety of ICIs in this setting. Interestingly, multiple potential biomarkers, including tumor mutational burden (TMB), microsatellite instability (MSI) status, and PD-L1 expression level, have inconsistently predicted response to ICIs in patients with HCC. Limited evidence is available to guide treatment choice in later-line settings after progressing on ICIs, and decisions should be based on the safety profile of the treatment regimen and patient preference. Multiple trials are ongoing to elucidate the optimal treatment sequence. Of note, we believe that TKIs (e.g., cabozantinib, regorafenib, lenvatinib, and sorafenib) could be more beneficial in later-line settings to broaden inhibition of other pathways apart from vascular endothelial growth factor (VEGF). When conventional treatment options are exhausted, tissue biopsy may be helpful to reveal rare targetable mutations, such as RET gene fusions.

RIFLE: a Phase II trial of stereotactic ablative radiotherapy combined with fruquintinib and tislelizumab in metastatic colorectal cancer

Background

Currently, the prognosis for metastatic colorectal cancer (mCRC) still remains poor. The management of mCRC has become manifold because of the varied advances in the systemic and topical treatment approaches. For patients with limited number of metastases, radical local therapy plus systemic therapy can be a good choice to achieve long-term tumor control. In this study, we aimed to explore the efficacy and safety of the combination of fruquintinib, tislelizumab, and stereotactic ablative radiotherapy (SABR) in mCRC (RIFLE study).

Methods

RIFLE was designed as a single-center, single-arm, prospective Phase II clinical trial. A total of 68 mCRC patients who have failed the first-line standard treatment will be recruited in the safety run-in phase (n = 6) and the expansion phase (n = 62), respectively. Eligible patients will receive SABR followed by fruquintinib (5 mg, d1-14, once every day) and tislelizumab (200 mg, d1, once every 3 weeks) within 2 weeks from completion of radiation. The expansion phase starts when the safety of the treatment is determined (dose limiting toxicity occur in no more than one-sixth of patients in the run-in phase). The primary end point is the objective response rate. The secondary end points include the disease control rate, duration of response, 3-year progression-free survival rate, 3-year overall survival rate, and toxicity.

Conclusions

The results of this trial will provide a novel insight into SABR in combination with PD-1 antibody and vascular endothelial growth factor receptor inhibitor in the systematic treatment of metastatic colorectal cancer, which is expected to provide new therapeutic strategies and improve the prognosis for mCRC patients.

Trial registration

NCT04948034 (ClinicalTrials.gov).

First-line regorafenib with nivolumab and chemotherapy in advanced oesophageal, gastric, or gastro-oesophageal junction cancer in the USA: a single-arm, single-centre, phase 2 trial

BACKGROUND

The addition of nivolumab to chemotherapy improves survival in patients with advanced oesophagogastric (oesophageal, gastric, or gastro-oesophageal junction) adenocarcinoma; however, outcomes remain poor. We assessed the safety and activity of regorafenib in combination with nivolumab and chemotherapy in the first-line treatment of advanced oesophagogastric adenocarcinoma.

METHODS

This investigator-initiated, single-arm, phase 2 trial in adult patients (aged ≥18 years) with previously untreated, HER2-negative, metastatic oesophagogastric adenocarcinoma was done at the Memorial Sloan Kettering Cancer Center (New York, NY, USA). Eligible patients had measurable disease or non-measurable disease that was evaluable (defined by Response Evaluation Criteria in Solid Tumours [RECIST] version 1.1) and Eastern Cooperative Oncology Group performance status of 0 or 1. Patients received FOLFOX chemotherapy (fluorouracil [400 mg/m2 bolus followed by 2400 mg/m2 over 48 h], leucovorin [400 mg/m2], and oxaliplatin [85 mg/m2]) and nivolumab (240 mg) intravenously on days 1 and 15, and oral regorafenib (80 mg) on days 1-21 of a 28-day cycle. Treatment was continued until disease progression (defined by RECIST version 1.1), unacceptable toxicity, or withdrawal of consent. The primary endpoint was 6-month progression-free survival in the per-protocol population (ie, all participants who received a dose of all study treatments). The regimen would be considered worthy of further investigation if at least 24 of 35 patients were progression free at 6 months. Safety was assessed in all participants who received at least one dose of any study treatment. This trial is registered with ClinicalTrials.gov, NCT04757363, and is now complete.

FINDINGS

Between Feb 11, 2021, and May 4, 2022, 39 patients were enrolled, received at least one dose of study drug, and were included in safety analyses. 35 patients were evaluable for 6-month progression-free survival. Median age was 57 years (IQR 52-66), nine (26%) patients were women, 26 (74%) were men, 28 (80%) were White, and seven (20%) were Asian. At data cutoff (March 3, 2023), median follow-up was 18·1 months (IQR 12·7-20·4). The primary endpoint was reached, with 25 (71%; 95% CI 54-85) of 35 patients progression free at 6 months. Nine (26%) of 35 patients had disease progression and one (3%) patient died; the death was unrelated to treatment. The most common adverse event of any grade was fatigue (36 [92%] of 39). The most common grade 3 or 4 adverse events were decreased neutrophil count (18 [46%]), hypertension (six [15%]), dry skin, pruritus, or rash (five [13%]), and anaemia (four [10%]). Serious treatment-related adverse events occurred in ten (26%) patients, which were acute kidney injury (three [8%]), hepatotoxicity (two [5%]), sepsis (two [5%]), dry skin, pruritus, or rash (one [3%]), nausea (one [3%]), and gastric perforation (one [3%]). There were no treatment-related deaths.

INTERPRETATION

Regorafenib can be safely combined with nivolumab and chemotherapy and showed promising activity in HER2-negative metastatic oesophagogastric cancer. A randomised, phase 3 clinical trial is planned.

FUNDING

Bristol Myers Squibb, Bayer and National Institutes of Health/National Cancer Institute.

Regorafenib inhibits growth, survival and angiogenesis in nasopharyngeal carcinoma and is synergistic with Mcl-1 inhibitor

OBJECTIVES

Regorafenib is an oral multi-kinase inhibitor approved for various metastatic/advanced cancers, and has been investigated in clinical trials in many other tumour entities. The purpose of this study was to evaluate the therapeutic potential of regorafenib for nasopharyngeal carcinoma (NPC).

METHODS

Cellular proliferation, survival, apoptosis and colony formation assays were performed and combination index was determined. NPC xenograft tumour models were established. In vitro and In vivo angiogenesis assays were performed.

KEY FINDINGS

Regorafenib is effective against a panel of NPC cell lines regardless of cellular origin and genetic profiling while sparing normal nasal epithelial cells. The predominant inhibitory effects of regorafenib in NPC are anchorage-dependent and anchorage-independent growth rather than survival. Apart from tumour cells, regorafenib potently inhibits angiogenesis. Mechanistically, regorafenib inhibits multiple oncogenic pathways including Raf/Erk/Mek and PI3K/Akt/mTOR. Regorafenib decreases Bcl-2 but not Mcl-1 level in NPC cells. The in vitro observations are evident in in vivo NPC xenograft mouse model. The combination of Mcl-1 inhibitor with regorafenib is synergistic in inhibiting NPC growth without causing systemic toxicity in mice.

CONCLUSIONS

Our findings also support further clinical investigation of regorafenib and Mcl-1 inhibitor for NPC treatment.

Refractory microsatellite stable metastatic colorectal cancer with ERBB2/ERBB3 mutation may be preferred population for regorafenib plus PD-1 inhibitor therapy: a real-world study

Background

Microsatellite stable (MSS) colorectal cancer (CRC) has been referred to as the "cold tumor" because of almost no response to anti-programmed death-1 (PD-1) antibody. A recent REGONIVO trial showed that regorafenib plus nivolumab had an encouraging efficacy in MSS metastatic CRC (mCRC). However, only a small subset of patients may benefit from the combination therapy. We aim to evaluate the efficacy and safety data of immune checkpoint inhibitors combined with regorafenib in refractory MSS mCRC and to discover biomarkers that can effectively stratify the beneficial patient population.

Methods

We retrospectively analyzed patients with MSS mCRC who received regorafenib combined with anti-PD-1 antibody therapy. The objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and status of gene mutation were reviewed and evaluated.

Results

Twenty-one patients received combination treatment. At a median treatment duration of 4 months, one patient achieved complete response, three patients achieved partial response, and two patients achieved stable disease as the best response. The ORR and DCR were 19% and 28.5% in the overall population, respectively. The median PFS was 4 months, and the median OS was 25 months. Only erbb2 receptor tyrosine kinase 2/erbb3 receptor tyrosine kinase 3 (ERBB2/ERBB3) mutation status was confirmed to be a potential predictive factor for effective treatment. In patients with ERBB2/ERBB3 mutation, ORR, DCR, and PFS exhibited significant improvements in comparison with that in wild-type patients. Grade 3 or higher treatment-related adverse events occurred in three patients (14.3%).

Conclusions

Regorafenib in combination with PD-1 inhibitor provides a feasible treatment regimen for refractory MSS mCRC with tolerated toxicity. Patients with ERBB2/ERBB3 mutation may be the preferred population for this combination regimen.

Angiogenic signaling pathways and anti-angiogenic therapy for cancer

Angiogenesis, the formation of new blood vessels, is a complex and dynamic process regulated by various pro- and anti-angiogenic molecules, which plays a crucial role in tumor growth, invasion, and metastasis. With the advances in molecular and cellular biology, various biomolecules such as growth factors, chemokines, and adhesion factors involved in tumor angiogenesis has gradually been elucidated. Targeted therapeutic research based on these molecules has driven anti-angiogenic treatment to become a promising strategy in anti-tumor therapy. The most widely used anti-angiogenic agents include monoclonal antibodies and tyrosine kinase inhibitors (TKIs) targeting vascular endothelial growth factor (VEGF) pathway. However, the clinical benefit of this modality has still been limited due to several defects such as adverse events, acquired drug resistance, tumor recurrence, and lack of validated biomarkers, which impel further research on mechanisms of tumor angiogenesis, the development of multiple drugs and the combination therapy to figure out how to improve the therapeutic efficacy. Here, we broadly summarize various signaling pathways in tumor angiogenesis and discuss the development and current challenges of anti-angiogenic therapy. We also propose several new promising approaches to improve anti-angiogenic efficacy and provide a perspective for the development and research of anti-angiogenic therapy.

The Role of Angiogenesis Targeted Therapies in Metastatic Advanced Gastric Cancer: A Narrative Review

Since bevacizumab was first approved by the U.S. Food and Drug Administration as an anti-angiogenic therapy in 2004, angiogenesis-targeted therapy has been developed for various types of solid tumors. To date, ramucirumab and apatinib are clinically available as treatments for metastatic advanced gastric cancer (AGC). Ramucirumab demonstrated prolonged survival as second-line therapy of metastatic AGC in the RAINBOW and REGARD trials. However, neither ramucirumab extended survival in treatment-naïve patients with AGC in the RAINFALL or RAINSTORM trials nor bevacizumab in the AVAGAST and AVATAR trials. Apatinib demonstrated superior efficacy over the best supportive care in a Chinese phase III trial but not in an international phase III (ANGEL) trial. Currently, combination therapy of ramucirumab with irinotecan or FTD/TPI is being evaluated in the third-line setting, assessing the efficacy of continuous angiogenesis inhibition from second- to third-line therapy. Recently, the role of angiogenesis inhibition via immunomodulators is attractive to clinicians. Emerging results of several early-phase clinical trials indicated the promising antitumor activity of angiogenesis inhibition in combination with immune therapy. This review offers an overview of the history of clinical trials focused on anti-angiogenic for patients with AGC and presents future perspectives in this area.

Role of tumor-associated macrophages in common digestive system malignant tumors

Many digestive system malignant tumors are characterized by high incidence and mortality rate. Increasing evidence has revealed that the tumor microenvironment (TME) is involved in cancer initiation and tumor progression. Tumor-associated macrophages (TAMs) are a predominant constituent of the TME, and participate in the regulation of various biological behaviors and influence the prognosis of digestive system cancer. TAMs can be mainly classified into the antitumor M1 phenotype and protumor M2 phenotype. The latter especially are crucial drivers of tumor invasion, growth, angiogenesis, metastasis, immunosuppression, and resistance to therapy. TAMs are of importance in the occurrence, development, diagnosis, prognosis, and treatment of common digestive system malignant tumors. In this review, we summarize the role of TAMs in common digestive system malignant tumors, including esophageal, gastric, colorectal, pancreatic and liver cancers. How TAMs promote the development of tumors, and how they act as potential therapeutic targets and their clinical applications are also described.

Effects of regorafenib on the mononuclear/phagocyte system and how these contribute to the inhibition of colorectal tumors in mice

BACKGROUND

Regorafenib was previously shown to reduce tumor-associated macrophages and potently inhibit colony-stimulating factor 1 receptor (CSF1R), also known as CD115, in biochemical assays. The CSF1R signaling pathway is essential in the biology of the mononuclear/phagocyte system, which can promote the development of cancer.

METHODS

A deeper investigation of regorafenib's effects on CSF1R signaling was performed using preclinical in vitro and in vivo studies with syngeneic CT26 and MC38 mouse models of colorectal cancer. Peripheral blood and tumor tissue were analyzed mechanistically by flow cytometry using antibodies against CD115/CSF1R and F4/80 and by ELISA for chemokine (C-C motif) ligand 2 (CCL2) levels. These read-outs were correlated with drug levels for the detection of pharmacokinetic/pharmacodynamic relationships.

RESULTS

Potent inhibition of CSF1R by regorafenib and its metabolites M-2, M-4, and M-5 was confirmed in vitro in RAW264.7 macrophages. The dose-dependent growth inhibition of subcutaneous CT26 tumors by regorafenib was associated with a significant reduction in both the number of CD115^hi monocytes in peripheral blood and the number of selective subpopulations of intratumoral F4/80^hi tumor-associated macrophages. CCL2 levels were not affected by regorafenib in blood but increased in tumor tissue, which may contribute to drug resistance and prevent complete tumor remission. An inverse relationship between regorafenib concentration and the number of CD115^hi monocytes and CCL2 levels was observed in peripheral blood, supporting the mechanistic involvement of regorafenib.

CONCLUSIONS

These findings may be clinically useful in optimizing drug dosing using blood-based pharmacodynamic markers and in identifying resistance mechanisms and ways to overcome them by appropriate drug combinations.

SN-38, an active metabolite of irinotecan, enhances anti-PD-1 treatment efficacy in head and neck squamous cell carcinoma

Anti-programmed cell death 1 (anti-PD-1) therapy shows definite but modest activity in patients with advanced/metastatic head and neck squamous cell carcinoma (HNSCC). Preliminary evidence suggests that SN-38, an activated form of irinotecan that increases expression of the transcription factor FoxO3a, can suppress programmed cell death ligand-1 (PD-L1) expression in breast and ovarian tumor models. We analyzed the SN-38-mediated activation of natural killer cells in vitro and explored the efficacy of SN-38 in combination with anti-PD-1 for treatment in vivo. In vitro, SN-38 enhanced the expression of FoxO3a and reduced the expression of c-Myc and PD-L1 dose-dependently in tumor cells. Low-dose SN-38 increased interferon-γ secretion by NK cells and promoted NK cell-mediated cytotoxicity in tumor cells. In vivo studies revealed that at non-cytotoxic drug concentrations, SN-38 significantly enhanced anti-PD-1 activity in suppressing murine tumor growth. We found increased NK cell and CD8⁺ T-cell infiltration in post-treatment tumors. RNA-seq analysis indicated that SN-38 increased the enrichment of immune cells and biological function genes related to the immune responses. SN-38 is a potentially beneficial adjunct to checkpoint inhibitor therapy in HNSCC. Further studies exploring its mechanism of action and possible applications are necessary. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Recent advances in immunotherapy and molecular targeted therapy for gastric cancer

Our increasing understanding of the molecular biological characteristics of cancer and of cancer genomics is facilitating the development of immunotherapy and molecular targeted drugs for gastric cancer. After the approval of immune checkpoint inhibitors (ICIs) for melanoma in 2010, many different cancers have been shown to respond to such treatments. Thus, the anti-PD-1 antibody nivolumab was reported to prolong survival in 2017, and ICIs have become the mainstay of treatment development. Many clinical trials of combination therapies with cytotoxic agents and molecular-targeted agents, as well as combinations of immunotherapeutic agents acting via different mechanisms, are currently underway for each treatment line. As a result, further improvements in therapeutic outcomes for gastric cancer are anticipated in the near future.

Advances in immune checkpoint inhibitor combination strategies for microsatellite stable colorectal cancer

Immune checkpoint inhibitors have reshaped the prognostic of several tumor types, including metastatic colorectal tumors with microsatellite instability (MSI). However, 90-95% of metastatic colorectal tumors are microsatellite stable (MSS) in which immunotherapy has failed to demonstrate meaningful clinical results. MSS colorectal tumors are considered immune-cold tumors. Several factors have been proposed to account for this lack of response to immune checkpoint blockade including low levels of tumor infiltrating lymphocytes, low tumor mutational burden, a high rate of WNT/β-catenin pathway mutations, and liver metastases which have been associated with immunosuppression. However, studies with novel combinations based on immune checkpoint inhibitors are showing promising activity in MSS colorectal cancer. Here, we review the underlying biological facts that preclude immunotherapy activity, and detail the different immune checkpoint inhibitor combinations evaluated, along with novel immune-based therapies, to overcome innate mechanisms of resistance in MSS colorectal cancer.

Real-world systemic sequential therapy with regorafenib for recurrent hepatocellular carcinoma: analysis of 93 cases from a single center

BACKGROUND

Regorafenib is an oral multikinase inhibitor and became the first second-line systemic treatment for hepatocellular carcinoma (HCC) following the phase III RESORCE trial. This single-center study retrospectively analyzed the clinical data and follow-up results of patients with recurrent HCC treated with regorafenib and discussed the prognostic factors to provide guidance for clinical treatment.

METHODS

Ninety-three recurrent HCC patients were enrolled in the research and follow up from December 2017 to December 2020. Clinical and pathological data were collected. SPSS software v26.0 was used (Chicago, IL, USA) for statistical analysis. A two-sided P < 0.05 was considered statistically significant.

RESULTS

The patients included 81 males and 12 females with a median age of 57 years. Eighty-seven patients had hepatitis B virus (HBV) infection. The objective response rate (ORR) was 14.0%, and the disease control rate (DCR) was 62.4%. The median overall survival (mOS) and median time to progression (mTTP) were 15.9 and 5.0 months. Multivariate analysis showed that Child-Pugh classification, the Eastern Cooperative Oncology Group performance status (ECOG PS), the neutrophil-to-lymphocyte ratio (NLR), combined treatment, and the time from first diagnosis of HCC to second-line treatment were independent factors affecting the prognosis of recurrent HCC patients.

CONCLUSIONS

This real-world study demonstrated similar findings to those of the RESORCE trial. Regorafenib could effectively improve the prognosis of patients after first-line treatment failure. Combination therapy under multidisciplinary treatment (MDT) team guidance could be effective in impeding tumor progression and improving the prognosis of recurrent HCC patients.

Current Landscape and Potential Challenges of Immune Checkpoint Inhibitors in Microsatellite Stable Metastatic Colorectal Carcinoma

Colorectal cancer (CRC) is the third most frequent cancer and the second most common cause of cancer-related death in Europe. High microsatellite instability (MSI-H) due to a deficient DNA mismatch repair (dMMR) system can be found in 5% of metastatic CRC (mCRC) and has been established as a biomarker of response to immunotherapy in these tumors. Therefore, immune checkpoint inhibitors (ICIs) in mCRC with these characteristics were evaluated with results showing remarkable response rates and durations of response. The majority of mCRC cases have high levels of DNA mismatch repair proteins (pMMR) with consequent microsatellite stability or low instability (MSS or MSI-low), associated with an inherent resistance to ICIs. This review aims to provide a comprehensive analysis of the possible approaches to overcome the mechanisms of resistance and evaluates potential biomarkers to establish the role of ICIs in pMMR/MSS/MSI-L (MSS) mCRC.

Influence of Lenvatinib on the Functional Reprogramming of Peripheral Myeloid Cells in the Context of Non-Medullary Thyroid Carcinoma

Lenvatinib is a multitarget tyrosine kinase inhibitor (TKI) approved for the treatment of several types of cancers, including metastatic differentiated thyroid cancer (DTC). The intended targets include VEGFR 1-3, FGFR 1-4, PDGFRα, RET, and KIT signaling pathways, but drug resistance inevitably develops and a complete cure is very rare. Recent data has revealed that most of the TKIs have additional 'off-target' immunological effects, which might contribute to a protective antitumor immune response; however, human cellular data are lacking regarding Lenvatinib-mediated immunomodulation in DTC. Here, we investigated in ex vivo models the impact of Lenvatinib on the function of immune cells in healthy volunteers. We found that monocytes and macrophages were particularly susceptible to Lenvatinib, while neutrophiles and lymphocytes were less affected. In tumor-immune cell co-culture experiments, Lenvatinib exerted a broad inhibitory effect on the proinflammatory response in TC-induced macrophages. Interestingly, Lenvatinib-treated cells had decreased cellular M2 membrane markers, whereas they secreted a significantly higher level of the anti-inflammatory cytokine IL-10 upon LPS stimulation. In addition, prolonged exposure to Lenvatinib impaired macrophages survival and phenotypical differentiation, which was accompanied by remarkable morphological changes and suppressed cellular metabolic activity. These effects were mediated by myeloid cell-intrinsic mechanisms which are independent of Lenvatinib's on-target activity. Finally, using specific inhibitors, we argue that dual effects on p38 MAPK and Syk pathways are likely the underlying mechanism of the off-target immunological effects we observed in this study. Collectively, our data show the immunomodulatory properties of Lenvatinib on human monocytes. These insights could be harnessed for the future design of novel treatment strategies involving a combination of Lenvatinib with other immunotherapeutic agents.

Tyrosine kinase inhibitors as potential sensitizers of adoptive T cell therapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a high-incidence malignant tumor worldwide and lacks effective treatment options. Targeted drugs are the preferred recommendations for the systemic treatment of hepatocellular carcinoma. Immunotherapy is a breakthrough in the systemic treatment of malignant tumors, including HCC. However, either targeted therapy or immunotherapy alone is inefficient and has limited survival benefits on part of HCC patients. Investigations have proved that tyrosine kinase inhibitors (TKIs) have regulatory effects on the tumor microenvironment and immune response, which are potential sensitizers for immunotherapy. Herein, a combination therapy using TKIs and immunotherapy has been explored and demonstrated to improve the effectiveness of treatment. As an effective immunotherapy, adoptive T cell therapy in solid tumors is required to improve tumor infiltration and killing activity which can be possibly achieved by combination with TKIs.

Curcumin Reprograms TAMs from a Protumor Phenotype towards an Antitumor Phenotype via Inhibiting MAO-A/STAT6 Pathway

M1 phenotype macrophages have anticancer characteristics, whereas M2 phenotype macrophages promote tumor growth and metastasis. A higher M1/M2 ratio, therefore, has a beneficial effect on the tumor immune microenvironment, thereby inhibiting tumor growth. The natural alkaloid curcumin is found to have anticancer properties. However, the mechanism remains unclear. In this study, a cell co-culture system and M2 macrophage model were used to evaluate the effects of curcumin on tumor-associated macrophage (TAM) phenotypes. Our results demonstrate that curcumin reprogrammed the M2 macrophages by reducing the level of anti-inflammatory cytokines (TGF-β, Arg-1, and IL-10) and an M2 surface marker (CD206) induced by Cal27 cells or IL-4, as well as upregulating proinflammatory cytokines (TNF-α, iNOS, and IL-6) and an M1 surface marker (CD86). The in vitro assays suggested that curcumin treatment suppressed the migration and invasion of the Cal27 cells induced by the M2-like macrophages. Mechanistically, the repolarization of TAMs may be attributed to the inhibition of monoamine oxidase A (MAO-A)/STAT6 signaling after curcumin treatment. Collectively, our results show that the anticancer effects of curcumin could be explained by reprogramming TAMs from a protumor phenotype towards an antitumor phenotype.

Current and emerging anti-angiogenic therapies in gastrointestinal and hepatobiliary cancers

Gastrointestinal tumours are a heterogeneous group of neoplasms that arise in the gastrointestinal tract and hepatobiliary system. Their incidence is rising globally and they currently represent the leading cause of cancer-related mortality worldwide. Anti-angiogenic agents have been incorporated into the treatment armamentarium of most of these malignancies and have improved survival outcomes, most notably in colorectal cancer and hepatocellular carcinoma. New treatment combinations with immunotherapies and other agents have led to unprecedented benefits and are revolutionising patient care. In this review, we detail the mechanisms of action of anti-angiogenic agents and the preclinical rationale underlying their combinations with immunotherapies. We review the clinical evidence supporting their use across all gastrointestinal tumours, with a particular emphasis on colorectal cancer and hepatocellular carcinoma. We discuss available biomarkers of response to these therapies and their utility in routine clinical practice. Finally, we summarise ongoing clinical trials in distinct settings and highlight the preclinical rationale supporting novel combinations.

The Interplay between Anti-Angiogenics and Immunotherapy in Colorectal Cancer

Simple Summary

Colorectal cancer is a frequent and lethal neoplasm. The tumor often creates new vessels to grow and spread—a process called ‘angiogenesis’. Therefore, drugs blocking angiogenesis are effective against this malignancy. On the other side, immune checkpoint inhibitors, which unleash the immune system to fight against tumors, have limited efficacy in patients carrying instability of DNA regions called microsatellites. However, there is an interaction between angiogenic factors and the immune system. This gives a chance to combine anti-angiogenic agents and immune checkpoint inhibitors to improve the efficacy of treating this malignancy.

Abstract

Angiogenesis, a hallmark of cancer, plays a fundamental role in colorectal cancer (CRC). Anti-angiogenic drugs and chemotherapy represent a standard of care for treating metastatic disease. Immune checkpoint inhibitors (ICIs) have changed the therapeutic algorithm of many solid tumors. However, the efficacy of ICIs is limited to mCRC patients carrying microsatellite instability (MSI-H), which represent approximately 3–5% of mCRC. Emerging evidence suggests that anti-angiogenic drugs could exhibit immunomodulatory properties. Thus, there is a strong rationale for combining anti-angiogenics and ICIs to improve efficacy in the metastatic setting. Our review summarizes the pre-clinical and clinical evidence regarding the combination of anti-angiogenics and ICIs in mCRC to deepen the possible application in daily clinical practice.

Tumor-associated macrophages in liver cancer: From mechanisms to therapy

Multidimensional analyses have demonstrated the presence of a unique tumor microenvironment (TME) in liver cancer. Tumor-associated macrophages (TAMs) are among the most abundant immune cells infiltrating the TME and are present at all stages of liver cancer progression, and targeting TAMs has become one of the most favored immunotherapy strategies. In addition, macrophages and liver cancer cells have distinct origins. At the early stage of liver cancer, macrophages can provide a niche for the maintenance of liver cancer stem cells. In contrast, cancer stem cells (CSCs) or poorly differentiated tumor cells are key factors modulating macrophage activation. In the present review, we first propose the origin connection between precursor macrophages and liver cancer cells. Macrophages undergo dynamic phenotypic transition during carcinogenesis. In this course of such transition, it is critical to determine the appropriate timing for therapy and block specific markers to suppress pro-tumoral TAMs. The present review provides a more detailed discussion of transition trends of such surface markers than previous reviews. Complex crosstalk occurs between TAMs and liver cancer cells. TAMs play indispensable roles in tumor progression, angiogenesis, and autophagy due to their heterogeneity and robust plasticity. In addition, macrophages in the TME interact with other immune cells by directing cell-to-cell contact or secreting various effector molecules. Similarly, tumor cells combined with other immune cells can drive macrophage recruitment and polarization. Despite the latest achievements and the advancements in treatment strategies following TAMs studies, comprehensive discussions on the communication between macrophages and cancer cells or immune cells in liver cancer are currently lacking. In this review, we discussed the interactions between TAMs and liver cancer cells (from cell origin to maturation), the latest therapeutic strategies (including chimeric antigen receptor macrophages), and critical clinical trials for hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA) to provide a rationale for further clinical investigation of TAMs as a potential target for treating patients with liver cancer.

Immunomodulatory effects of regorafenib: Enhancing the efficacy of anti-PD-1/PD-L1 therapy

Anti-PD-1/PD-L1 therapy has shown significant benefits in the treatment of a variety of malignancies. However, not all cancer patients can benefit from this strategy due to drug resistance. Therefore, there is an urgent need for methods that can effectively improve the efficacy of anti-PD-1/PD-L1 therapy. Combining anti-PD-1/PD-L1 therapy with regorafenib has been demonstrated as an effective method to enhance its therapeutic effect in several clinical studies. In this review, we describe common mechanisms of resistance to anti-PD-1/PD-L1 therapy, including lack of tumor immunogenicity, T cell dysfunction, and abnormal expression of PD-L1. Then, we illustrate the role of regorafenib in modifying the tumor microenvironment (TME) from multiple aspects, which is different from other tyrosine kinase inhibitors. Regorafenib not only has immunomodulatory effects on various immune cells, but can also regulate PD-L1 and MHC-I on tumor cells and promote normalization of abnormal blood vessels. Therefore, studies on the synergetic mechanism of the combination therapy may usher in a new era for cancer treatment and help us identify the most appropriate individuals for more precise treatment.

Updated Efficacy Outcomes of Anti-PD-1 Antibodies plus Multikinase Inhibitors for Patients with Advanced Gastric Cancer with or without Liver Metastases in Clinical Trials

PURPOSE

We previously reported preliminary activity of regorafenib plus nivolumab (REGONIVO) or lenvatinib plus pembrolizumab (LENPEM) in advanced gastric cancer (AGC). Meanwhile, several studies demonstrated liver metastases are less responsive to immunotherapy.

PATIENTS AND METHODS

Combined efficacy outcomes with a longer follow-up in a phase Ib trial of REGONIVO and a phase II trial of LENPEM were examined in AGC with or without liver metastases (REGONIVO plus LENPEM cohort). We also investigated the efficacy of anti-PD-1 monotherapies (anti-PD-1 monotherapy cohort). A comparison of the immune microenvironment between gastric primary tumors and liver metastases was also conducted by multiplex IHC.

RESULTS

In the REGONIVO plus LENPEM cohort, with a median follow-up of 14.0 months, objective response rate (ORR), median progression-free survival (mPFS), and median overall survival (mOS) were 46%, 7.8 months, and 15.6 months in patients with liver metastases, while 69%, 6.9 months, and 15.5 months in those without. In the anti-PD-1 monotherapy cohort, with a median follow-up of 27.6 months, ORR, mPFS, and mOS were 9%, 1.4 months, and 6.4 months in patients with liver metastases, while 22%, 2.3 months, and 9.0 months in those without. Multiplex IHC revealed liver metastases were associated with an abundance of immune-suppressive cells, such as tumor-associated macrophages and regulatory T cells, with fewer CD8+ T cells compared with gastric primary tumors.

CONCLUSIONS

Anti-PD-1 antibodies plus regorafenib or lenvatinib for AGC showed promising antitumor activity with a longer follow-up, irrespective of liver metastases status, despite a more immune-suppressive tumor microenvironment in liver metastases.