Interaction of tumor-associated macrophages and cancer chemotherapy

Histological tumor necrosis predicts decreased survival after neoadjuvant chemotherapy in head and neck squamous cell carcinoma

OBJECTIVE

Despite growing interest in neoadjuvant therapies, there are no methods to predict radio- (RT) or chemoradiotherapy (CRT) response in head and neck squamous cell carcinoma (HNSCC). The aim of this research was to study the effect of neoadjuvant RT or CRT on the tumor immune landscape and patient survival in HNSCC.

METHODS

All HNSCC patients treated with neoadjuvant RT or CRT (n = 53) were identified from a retrospective cohort of 1033 patients. Pre- and post-neoadjuvant cancer samples from the same patient were analyzed with biomarkers related to cancer immunology: tumor-infiltrating lymphocytes (CD8), tumor-associated macrophages (CD68, CD206, Clever-1), immune response regulator (PD-L1) and histologic tumor necrosis. Outcomes of interest were individual immune landscape profiling and its impact on 5-year overall survival (OS) in HNSCC patients treated with neoadjuvant RT/CRT.

RESULTS

Results from 588 whole-section stainings revealed multiple statistically significant alterations in immune landscape in response to RT/CRT. Pretreatment tumor necrosis was the most useful biomarker in predicting poor outcome, as the OS was 14.3% with necrosis and 48.5% without necrosis (HR 2.87; 95% CI: 1.23 to 6.66, p=0.014). In addition, an artificial intelligence-based (AI) deep learning method for identifying tumor necrosis from histopathological specimens was successfully developed. The predictive role of histological necrosis in neoadjuvant RT/CRT was validated in additional samples from 171 HNSCC patients untreated with neoadjuvant therapy.

CONCLUSIONS

Detection of tumor necrosis and AI-driven deep learning effectively predict neoadjuvant RT/CRT responses in HNSCC.

Ultrasound-Responsive Nanobubbles for Breast Cancer: Synergistic Sonodynamic, Chemotherapy, and Immune Activation through the cGAS-STING Pathway

Breast cancer remains the leading cause of cancer-related deaths among women worldwide, necessitating more effective treatment strategies. Chemotherapy combined with immunotherapy is the first-line treatment for breast cancer, but it still suffers from limited therapeutic efficiency and serious side effects, which are usually due to the poor delivery efficiency, drug resistance of tumor cells, and immunosuppressive tumor microenvironment. This study explores the development of ultrasound-responsive nanobubbles (Ce6/PTX Nbs) for targeted imaging and sonoimmunotherapy in breast cancer treatment. By integrating sonodynamic therapy (SDT), chemotherapy, and immunotherapy, the nanobubbles aim to address challenges such as poor drug delivery, systemic toxicity, and immune suppression in conventional therapies. The nanobubbles, composed of sonosensitizer chlorin e6 (Ce6)-modified phospholipid and loaded with the chemotherapeutic agent paclitaxel (PTX) enhancing drug-loading capacity, are designed to precisely target tumor sites via cyclic-RGD peptides. Upon ultrasound activation, Ce6 induces reactive oxygen species (ROS), promoting immunogenic cell death (ICD), while PTX disrupts tumor cell mitosis, enhancing the immune response. The nanobubbles' ultrasound responsiveness facilitates real-time imaging and controlled drug release, maximizing therapeutic efficacy while minimizing side effects. Key findings demonstrate that Ce6/PTX Nbs significantly reduced tumor growth in a 4T1 breast cancer model, enhanced immune activation via the cGAS-STING pathway, and increased the infiltration of CD8+ T cells in both primary and distant tumors. In combination with anti-PD-L1 checkpoint inhibitors, the treatment achieved a substantial suppression of tumor metastasis. This innovative approach offers a highly targeted, effective, and minimally toxic breast cancer treatment with potential for clinical translation due to its dual imaging and therapeutic capabilities.

Emerging immunologic approaches as cancer anti-angiogenic therapies

Targeting tumor angiogenesis, the formation of new blood vessels supporting cancer growth and spread, has been an intense focus for therapy development. However, benefits from anti-angiogenic drugs like bevacizumab have been limited by resistance stemming from activation of compensatory pathways. Recent immunotherapy advances have sparked interest in novel immunologic approaches that can induce more durable vascular pruning and overcome limitations of existing angiogenesis inhibitors. This review comprehensively examines these emerging strategies, including modulating tumor-associated macrophages, therapeutic cancer vaccines, engineered nanobodies and T cells, anti-angiogenic cytokines/chemokines, and immunomodulatory drugs like thalidomide analogs. For each approach, the molecular mechanisms, preclinical/clinical data, and potential advantages over conventional drugs are discussed. Innovative therapeutic platforms like nanoparticle delivery systems are explored. Moreover, the importance of combining agents with distinct mechanisms to prevent resistance is evaluated. As tumors hijack angiogenesis for growth, harnessing the immune system's specificity to disrupt this process represents a promising anti-cancer strategy covered by this review.

Targeting tumor-associated macrophages in colon cancer: mechanisms and therapeutic strategies

Colon cancer (CC) remains a primary contributor to cancer-related fatalities worldwide, driven by difficulties in early diagnosis and constrained therapeutic options. Recent studies underscore the importance of the tumor microenvironment (TME), notably tumor-associated macrophages (TAMs), in fostering malignancy progression and therapy resistance. Through their inherent plasticity, TAMs facilitate immunosuppression, angiogenic processes, metastatic spread, and drug tolerance. In contrast to M1 macrophages, which promote inflammatory and tumoricidal responses, M2 macrophages support tumor expansion and dissemination by exerting immunosuppressive and pro-angiogenic influences. Consequently, manipulating TAMs has emerged as a potential avenue to enhance treatment effectiveness. This review outlines the origins, polarization states, and functions of TAMs in CC, highlights their role in driving tumor advancement, and surveys ongoing efforts to target these cells for better patient outcomes. Emerging therapeutic strategies aimed at modulating TAM functions - including depletion strategies, reprogramming approaches that shift M2-polarized TAMs toward an M1 phenotype, and inhibition of key signaling pathways sustaining TAM-mediated immunosuppression-are currently under active investigation. These approaches hold promise in overcoming TAM - induced resistance and improving immunotherapeutic efficacy in CC.

Blood TCTP as a potential biomarker associated with immunosuppressive features and poor clinical outcomes in metastatic gastric cancer

BACKGROUND

No established biomarker exists for specific myeloid cell populations or in gastric cancer. This study aimed to explore the prognostic and immunological relevance of plasma translationally controlled tumor protein (TCTP) in patients with advanced gastric cancer treated with an immune checkpoint inhibitor and/or cytotoxic chemotherapy.

METHODS

Plasma samples were prospectively collected from the cohorts of patients with gastric cancer treated with first-line fluoropyrimidine plus platinum chemotherapy (n=143, cohort 1) and third-line nivolumab (n=165, cohort 2). Plasma TCTP levels were quantified using ELISA, and multiplex proteomic analysis (Olink) was conducted to assess expression levels of immune-related proteins. External single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics datasets were employed to validate the findings.

RESULTS

Patients with high plasma TCTP levels (TCTP-high group) exhibited poor progression-free survival (PFS) and overall survival (OS) with first-line chemotherapy compared with those with low levels (TCTP-low group) in cohort 1 (HR: 1.73 for PFS; 1.77 for OS). In the TCTP-high group, proteins associated with immunosuppressive myeloid cells, angiogenesis, and immune exclusion of T/natural killer (NK) cell function were upregulated, whereas proteins involved in T-cell activation/exhaustion were significantly upregulated in the TCTP-low group. scRNA-seq analyses identified a myeloid subset with high TPT1 (encoding TCTP) expression and TCTP-related molecules, enriched with inhibitory myeloid inflammation gene signatures and providing inhibitory signals to T/NK cells (Macrophage-chemokine). Spatial transcriptomics analyses revealed a tumor-cell-enriched cluster co-localized with the Macrophage-chemokine subset, which exhibited the highest TPT1 expression and a positive correlation between its abundance and average TPT1 levels. In nivolumab-treated patients (cohort 2), the high TCTP group was associated with poor survival outcomes (HR: 1.39 for PFS; 1.47 for OS).

CONCLUSIONS

Plasma TCTP is a prognostic biomarker, reflecting clinically relevant immunosuppressive myeloid signals in patients with gastric cancer.

Adipose tissue from oesophageal adenocarcinoma patients is differentially affected by chemotherapy and chemoradiotherapy regimens altering immune cell phenotype and cancer cell metabolism

Oesophageal adenocarcinoma (OAC) is a poor prognosis cancer with limited responses to standard of care treatments including chemotherapy and chemoradiotherapy. OAC has one of the strongest associations with obesity, its anatomical location surrounded by visceral adipose tissue has been postulated to intensify this association. Adipose tissue is a regulatory organ with many unknown downstream functions, including its direct response to chemotherapy and radiotherapy. To elucidate the role of visceral adipose tissue in this disease state, metabolic and secreted pro-inflammatory cytokines analysis was conducted on human ex-vivo adipose tissue explants following exposure to FLOT-chemotherapy and CROSS-chemoradiotherapy. To assess how these complex treated microenvironments impact cancer cell metabolism, dendritic cell, and macrophage phenotype, mitochondrial bioenergetics and surface markers expression were examined using seahorse technology and flow cytometry respectively. This study observed that chemotherapy and chemoradiotherapy differentially alter adipose tissue metabolism and secretome, with chemoradiotherapy increasing pro-inflammatory associated mediators (p<0.05). The chemoradiotherapy-treated adipose secretome increased cancer cell spare respiratory capacity and dendritic cell adhesion markers (p<0.05). In contrast, the chemotherapy-treated adipose microenvironment enhanced mitochondrial dysfunction in cancer cells, increasing their reliance on glycolysis and enhancing pro-inflammatory marker expression on LPS-primed macrophages (p<0.05). This study for the first time demonstrates how adipose tissue, and its microenvironment can be significantly impacted by chemotherapy and chemoradiotherapy. These alterations in the adipose secretome in response to therapeutic regimens elicited distinct effects on immune cell phenotype and cancer cells metabolism, raising the question, does the wider tumour microenvironment including the adipose milieu mitigate the efficacy of current treatments.

Inhibition of Thioredoxin-Reductase by Auranofin as a Pro-Oxidant Anticancer Strategy for Glioblastoma: In Vitro and In Vivo Studies

Reactive oxygen species (ROS) play a key role in cancer progression and antitumor therapy. Glioblastoma is a highly heterogeneous tumor with different cell populations exhibiting various redox statuses. Elevated ROS levels in cancer cells promote tumor growth and simultaneously make them more sensitive to anticancer drugs, but further elevation leads to cell death and apoptosis. Meanwhile, various subsets of tumor cells, such a glioblastoma stem cells (GSC) or the cells in tumor microenvironment (TME), demonstrate adaptive mechanisms to excessive ROS production by developing effective antioxidant systems such as glutathione- and thioredoxin-dependent. GSCs demonstrate higher chemoresistance and lower ROS levels than other glioma cells, while TME cells create a pro-oxidative environment and have immunosuppressive effects. Both subpopulations have become an attractive target for developing therapies. Increased expression of thioredoxin reductase (TrxR) is often associated with tumor progression and poor patient survival. Various TrxR inhibitors have been investigated as potential anticancer therapies, including nitrosoureas, flavonoids and metallic complexes. Gold derivatives are irreversible inhibitors of TrxR. Among them, auranofin (AF), a selective TrxR inhibitor, has proven its effectiveness as a drug for the treatment of rheumatoid arthritis and its efficacy as an anticancer agent has been demonstrated in preclinical studies in vitro and in vivo. However, further clinical application of AF could be challenging due to the low solubility and insufficient delivery to glioblastoma. Different delivery strategies for hydrophobic drugs could be used to increase the concentration of AF in the brain. Combining different therapeutic approaches that affect the redox status of various glioma cell populations could become a new strategy for treating brain tumor diseases.

The role of tumor-associated macrophages in lung cancer

Lung cancer remains a leading cause of cancer-related deaths worldwide, necessitating innovative treatments. Tumor-associated macrophages (TAMs) are primary immunosuppressive effectors that foster tumor proliferation, angiogenesis, metastasis, and resistance to therapy. They are broadly categorized into proinflammatory M1 and tumor-promoting M2 phenotypes, with elevated M2 infiltration correlating with poor prognosis. Strategies aimed at inhibiting TAM recruitment, depleting TAMs, or reprogramming M2 to M1 are therefore highly promising. Key signaling pathways, such as CSF-1/CSF-1R, IL-4/IL-13-STAT6, TLRs, and CD47-SIRPα, regulate TAM polarization. Additionally, macrophage-based drug delivery systems permit targeted agent transport to hypoxic regions, enhancing therapy. Preclinical studies combining TAM-targeted therapies with chemotherapy or immune checkpoint inhibitors have yielded improved responses and prolonged survival. Several clinical trials have also reported benefits in previously unresponsive patients. Future work should clarify the roles of macrophage-derived exosomes, cytokines, and additional mediators in shaping the immunosuppressive tumor microenvironment. These insights will inform the design of next-generation drug carriers and optimize combination immunotherapies within precision medicine frameworks. Elucidating TAM phenotypes and their regulatory molecules remains central to developing novel strategies that curb tumor progression and ultimately improve outcomes in lung cancer. Importantly, macrophage-based immunomodulation may offer expanded treatment avenues.

Progress of KRAS G12C inhibitors in the treatment of refractory colorectal cancer and strategies for drug resistance response

Colorectal cancer is the third most prevalent cancer in the world. Early screening and detection of tumours, active surgical radical treatment, postoperative adjuvant chemotherapy, targeted therapy, and immunotherapy are performed based on pathological staging and immunohistochemistry. Even with these measures, the 5-year survival rate of colorectal cancer is only 65%, and a considerable number of patients still experience tumour recurrence or even metastasis. The KRAS G12C mutation accounts for 3 to 4% of refractory colorectal cancer (advanced or metastatic colorectal cancer), and it was once believed that KRAS did not have a drug target until the emergence of KRAS G12C inhibitors provided targeted treatment for KRAS-mutated colorectal cancer. However, KRAS G12C inhibitors only produce moderate efficacy, and resistance occurs after a short remission. The mechanism of drug resistance in tumour cells is complex and diverse, and existing research has limited understanding of it. This review aims to elucidate the clinical trial progress of KRAS G12C inhibitors in refractory colorectal cancer, the research progress of drug resistance mechanisms, and the combined treatment strategies for drug resistance.

Effect of neoadjuvant chemotherapy on CD14 + CD16 + monocytes and soluble CD163 in Egyptian breast cancer patients

Neoadjuvant chemotherapy (NACT) influences the anticancer response by favourably altering the immune microenvironment. However, the effects of NACT on peripheral monocytes and their prognostic contribution to the NACT response have not yet been clarified. We aimed to evaluate the potential therapeutic responses and possible predictive value of double-positive (CD14 + CD16 +) monocytes and soluble CD163 (sCD163) in Egyptian breast cancer patients. Blood samples were obtained before and after neoadjuvant therapy from 30 patients with invasive breast cancer, and the expression of CD14 and CD16 was assessed via flow cytometry. The patients' sCD163 levels were also determined in both the serum and culture supernatant using enzyme-linked immunosorbent assay (ELISA). The results revealed that NACT was associated with a significant decrease in double-positive monocytes and sCD163 levels. In addition, both double-positive monocytes and serum sCD163 were significantly associated with a partial clinical response. Double-positive monocytes and serum sCD163 levels may be related to therapeutic response, suggesting their possible predictive value in breast cancer patients receiving NACT.

Successful repositioning of mertansine for improved chemotherapy by combining a polymer prodrug approach and PET imaging

Mertansine (DM1), a potent tumor-killing maytansinoid, requires conjugation to antibodies or incorporation into nanocarriers due to its high toxicity. However, these carriers often result in undesirable biodistribution, leading to rapid and long-term accumulation in the kidneys or liver and potentially increased toxicity. To overcome this limitation, we used the hydrophilic, biocompatible, and stealth properties of polyacrylamide (PAAm) as a scaffold to develop water-soluble PAAm-DM1 polymer prodrugs, leveraging PAAm's previous success in delivering paclitaxel via subcutaneous administration. To monitor distribution and predict efficacy, we have imparted Positron Emission Tomography (PET) imaging capabilities to well-defined PAAm-DM1 polymer prodrugs. Our studies demonstrated the same tumor accumulation and the same distribution of PAAm-DM1 in the main organs such as liver, kidneys muscle, regardless of delivery route (subcutaneous or intravenous). Interestingly, tumor accumulation of PAAm-DM1 was primarily driven by passive accumulation, as indicated by PET imaging, without significantly altering treatment efficacy. This suggests complex mechanisms, possibly involving immune system interactions by influencing notably the metabolism and clearance. To enhance therapeutic outcomes, we combined the polymer prodrug with immunotherapy, specifically anti-CTLA4. Our findings highlight the promising potential of PAAm-DM1, offering a novel formulation strategy for DM1 in cancer therapy.

Microbes, macrophages, and melanin: a unifying theory of disease as exemplified by cancer

It is widely accepted that cancer mostly arises from random spontaneous mutations triggered by environmental factors. Our theory challenges the idea of the random somatic mutation theory (SMT). The SMT does not fit well with Charles Darwin's theory of evolution in that the same relatively few mutations would occur so frequently and that these mutations would lead to death rather than survival of the fittest. However, it would fit well under the theory of evolution, if we were to look at it from the vantage point of pathogens and their supporting microbial communities colonizing humans and mutating host cells for their own benefit, as it does give them an evolutionary advantage and they are capable of selecting genes to mutate and of inserting their own DNA or RNA into hosts. In this article, we provide evidence that tumors are actually complex microbial communities composed of various microorganisms living within biofilms encapsulated by a hard matrix; that these microorganisms are what cause the genetic mutations seen in cancer and control angiogenesis; that these pathogens spread by hiding in tumor cells and M2 or M2-like macrophages and other phagocytic immune cells and traveling inside them to distant sites camouflaged by platelets, which they also reprogram, and prepare the distant site for metastasis; that risk factors for cancer are sources of energy that pathogens are able to utilize; and that, in accordance with our previous unifying theory of disease, pathogens utilize melanin for energy for building and sustaining tumors and metastasis. We propose a paradigm shift in our understanding of what cancer is, and, thereby, a different trajectory for avenues of treatment and prevention.

Engineered CAF-cancer cell hybrid membrane biomimetic dual-targeted integrated platform for multi-dimensional treatment of ovarian cancer

BACKGROUND

The efficacy of current therapies for ovarian cancer is limited due to the multilevel and complex tumor microenvironment (TME), which induces drug resistance and tumor progression in a single treatment regimen. Additionally, poor targeting and insufficient tissue penetration are important constraints in ovarian cancer treatment.

RESULT

We constructed PH20-overexpressing cancer-associated fibroblast (CAF)-cancer hybrid-cell membrane vesicles (PH20/CCM) for the dual-targeted delivery of carboplatin (CBP) and siRNA targeting p65 (sip65) loaded on the poly (dimethyl diallyl ammonium chloride) (PDDA)-modified MXene (PMXene), named PMXene@CBP-sip65 (PMCS). The nanoparticle PH20/CCM@PMCS could penetrate the extracellular matrix of tumor tissues and target both cancer cells and CAFs. After tumor cell internalization, these nanoparticles significantly inhibited cancer cell proliferation, generated reactive oxygen species, induced endoplasmic reticulum stress, and triggered immunogenic cell death. After CAF internalization, they inhibited pro-tumor factor release and activated immune effects, promoting immune system infiltration. In an experiment with ID8 homograft-carrying mice, PH20/CCM@PMCS significantly improved tumor inhibition and enhanced immune infiltration in tumor tissues.

CONCLUSION

These new therapeutic nanoparticles can simultaneously target tumor cells, CAFs, immune cells, and the extracellular matrix, thereby increasing treatment sensitivity and improving the TME. Therefore, these TME-regulating nanoparticles, combining specificity, efficiency, and effectiveness, provide new insights into ovarian cancer treatment.

SpatialKNifeY (SKNY): Extending from spatial domain to surrounding area to identify microenvironment features with single-cell spatial omics data

Single-cell spatial omics analysis requires consideration of biological functions and mechanisms in a microenvironment. However, microenvironment analysis using bioinformatic methods is limited by the need to detect histological morphology and extend it to the surrounding area. In this study, we developed SpatialKNifeY (SKNY), an image-processing-based toolkit that detects spatial domains that potentially reflect histology and extends these domains to the microenvironment. Using spatial transcriptomic data from breast cancer, we applied the SKNY algorithm to identify tumor spatial domains, followed by clustering of the domains, trajectory estimation, and spatial extension to the tumor microenvironment (TME). The results of the trajectory estimation were consistent with the known mechanisms of cancer progression. We observed tumor vascularization and immunodeficiency at mid- and late-stage progression in TME. Furthermore, we applied the SKNY to integrate and cluster the spatial domains of 14 patients with metastatic colorectal cancer, and the clusters were divided based on the TME characteristics. In conclusion, the SKNY facilitates the determination of the functions and mechanisms in the microenvironment and cataloguing of the features.

P2X7 receptor in macrophage polarization and its implications in neuroblastoma tumor behavior

Tumor-associated macrophages (TAMs) exhibit antitumor or protumor responses related to inflammatory (or M1) and alternative (or M2) phenotypes, respectively. The P2X7 receptor plays a key role in macrophage polarization, influencing inflammation and immunosuppression. In this study, we investigated the role of the P2X7 receptor in TAMs. Using P2X7 receptor-deficient macrophages, we analyzed gene expression profiles and their implications for neuroblastoma invasion and chemoresistance. Our results showed that P2X7 receptor deficiency altered the expression of classical polarization markers, such as nitric oxide synthase 2 (Nos2) and tumor necrosis factor-α (Tnf), as well as alternative phenotype markers, including mannose receptor C-type 1 (Mrc1) and arginase 1 (Arg1). P2X7 deficiency also influenced the expression of the ectonucleotidases Entpd1 and Nt5e and other purinergic receptors, especially P2ry2, suggesting compensatory mechanisms involved in macrophage polarization. In particular, TAMs deficient in P2X7 showed a phenotype with characteristics intermideiate between resting macrophages (M0) and M1 polarization rather than the M2-type phenotype like and wild-type TAM macrophages. In addition, P2rx7-/- TAMs regulated the expression of P2X7 receptor isoforms in neuroblastoma cells, with downregulation of the P2X7 A and B isoforms leading to a decrease in chemotherapy-induced cell death. However, TAMs expressing P2X7 downregulated only the B isoform, suggesting that TAMs play a role in modulating tumor behavior through P2X7 receptor isoform regulation. Taken together, our data underscore the regulatory function of the P2X7 receptor in orchestrating alternative macrophage polarization and in the interplay between tumor cells and TAMs. These findings help to clarify the complex interplay of purinergic signaling in cancer progression and open up avenues for future research and therapeutic interventions.

Integrins and integrin-driven secretory pathways as multi-dimensional regulators of tumor-associated macrophage recruitment and reprogramming in tumor microenvironment

Integrins, a group of transmembrane receptors, play a crucial role in mediating the interactions between cells and extracellular matrix (ECM) proteins. The intracellular signaling initiated by these cell-matrix interactions in leukocytes mediates many essential cellular processes such as survival, migration, metabolism, and other immunological functions. Macrophages, as phagocytes, participate in both proinflammatory and anti-inflammatory processes, including progression. Numerous reports have shown that the integrin-regulated secretome, comprising cytokines, chemokines, growth factors, proteases, and other bioactive molecules, is a crucial modulator of macrophage functions in tumors, significantly influencing macrophage programming and reprogramming within the tumor microenvironment (TME) in addition to driving their step-by-step entry process into tumor tissue spaces. Importantly, studies have demonstrated a pivotal role for integrin receptor-mediated secretome and associated signaling pathways in functional reprogramming from anti-tumorigenic to pro-tumorigenic phenotype in tumor-associated macrophages (TAMs). In this comprehensive review, we have provided an in-depth analysis of the latest findings of various key pathways, mediators, and signaling cascades associated with integrin-driven polarization of macrophages in tumors. This manuscript will provide an updated understanding of the modulation of inflammatory monocytes/ macrophages and TAMs by integrin-driven secretory pathways in various functions such as migration, differentiation, and their role in tumor progression, angiogenesis, and metastasis.

M2 macrophages secrete CCL20 to regulate iron metabolism and promote daunorubicin resistance in AML cells

Chemotherapy resistance is a significant clinical challenge in the treatment of leukemia. M2 macrophages have been identified as key contributors to the development of chemotherapy resistance in cancer, yet the precise mechanisms by which macrophages regulate this resistance remain elusive. Our study has identified CCL20 as a pivotal factor in the promotion of chemoresistance in AML cells by M2 macrophages. The chemotherapeutic agent daunorubicin induces a marked increase in ROS and lipid peroxidation levels within AML cells. This is accompanied by the inhibition of the SLC7A11/GCL/GPX4 signaling axis, elevated levels of intracellular free iron, disrupted iron metabolism, and consequent mitochondrial damage, ultimately leading to ferroptosis. Notably, CCL20 enhances the ability of AML cells to maintain iron homeostasis by upregulating SLC7A11 protein activity, mitigating mitochondrial damage, and inhibiting ferroptosis, thereby contributing to chemotherapy resistance. Furthermore, in vivo experiments demonstrated that blocking CCL20 effectively restores the sensitivity of AML cells to daunorubicin chemotherapy. Collectively, these findings underscore the complex interplay between M2 macrophages, CCL20 signaling, and chemotherapy resistance in AML, highlighting potential therapeutic avenues for intervention.

Effect of the lymphocyte-to-monocyte ratio on the prognosis of patients with obstructive colorectal cancer with a colonic stent: a retrospective multicenter study in Japan

PURPOSE

The prognostic value of the lymphocyte-to-monocyte (LMR) ratio has been reported for various cancers, including colorectal cancer (CRC). The insertion of colonic stents is considered effective for patients with surgically indicated obstructive CRC, but their LMR can vary depending on factors such as inflammation associated with stent dilation and improvement of obstructive colitis. However, the usefulness of the LMR in patients with obstructive CRC and colonic stents and the optimal timing for its measurement remain unclear. We conducted this study to investigate the relationship between the pre-stent LMR and the mid-term prognosis of patients with obstructive CRC and stents as a bridge to surgery (BTS).

METHODS

The subjects of this retrospective multicenter study were 175 patients with pathological stage 2 or 3 CRC. Patients were divided into a low pre-stent LMR group (n = 87) and a high pre-stent LMR group (n = 83).

RESULTS

Only 3-year relapse-free survival differed significantly between the low and high pre-stent LMR groups (39.9% vs. 63.6%, respectively; p = 0.015). The pre-stent LMR represented a prognostic factor for relapse-free survival in multivariate analyses (hazard ratio 2.052, 95% confidence interval 1.242-3.389; p = 0.005), but not for overall survival.

CONCLUSIONS

A low pre-stent LMR is a prognostic factor for postoperative recurrence in patients with obstructive CRC and a colonic stent as a BTS.

Leveraging insights from cancer to improve tuberculosis therapy

Exploring and exploiting the microenvironmental similarities between pulmonary tuberculosis (TB) granulomas and malignant tumors has revealed new strategies for more efficacious host-directed therapies (HDTs). This opinion article discusses a paradigm shift in TB therapeutic development, drawing on critical insights from oncology. We summarize recent efforts to characterize and overcome key shared features between tumors and granulomas, including excessive fibrosis, abnormal angiogenesis, hypoxia and necrosis, and immunosuppression. We provide specific examples of cancer therapy application to TB to overcome these microenvironmental abnormalities, including matrix-targeting therapies, antiangiogenic agents, and immune-stimulatory drugs. Finally, we propose a new framework for combining HDTs with anti-TB agents to maximize therapeutic delivery and efficacy while reducing treatment dosages, duration, and harmful side effects to benefit TB patients.

The oestrous cycle stage affects mammary tumour sensitivity to chemotherapy

The response of breast cancer to neoadjuvant chemotherapy (NAC) varies substantially, even when tumours belong to the same molecular or histological subtype1. Here we identify the oestrous cycle as an important contributor to this heterogeneity. In three mouse models of breast cancer, we show reduced responses to NAC when treatment is initiated during the dioestrus stage, when compared with initiation during the oestrus stage. Similar findings were observed in retrospective premenopausal cohorts of human patients. Mechanistically, the dioestrus stage exhibits systemic and localized changes, including (1) an increased number of cells undergoing epithelial-to-mesenchymal transition linked to chemoresistance2-4 and (2) decreased tumour vessel diameter, suggesting potential constraints to drug sensitivity and delivery. In addition, an elevated presence of macrophages, previously associated with chemoresistance induction5, characterizes the dioestrus phase. Whereas NAC disrupts the oestrous cycle, this elevated macrophage prevalence persists and depletion of macrophages mitigates the reduced therapy response observed when initiating treatment during dioestrus. Our data collectively demonstrate the oestrous cycle as a crucial infradian rhythm determining chemosensitivity, warranting future clinical studies to exploit optimal treatment initiation timing for enhanced chemotherapy outcomes.

Herbal Remedies for Hepatic Inflammation: Unravelling Pathways and Mechanisms for Therapeutic Intervention

Inflammation is a universal response of mammalian tissue to harm, comprising reactions to injuries, pathogens, and foreign particles. Liver inflammation is commonly associated with hepatocyte necrosis and apoptosis. These forms of liver cell injury initiate a sequence of events independent of the etiological basis for the inflammation and can result in hepatic disorders. It is also common for liver cancer. This review fundamentally focuses on the molecular pathways involved in hepatic inflammation. This review aims to explore the molecular pathways involved in hepatic inflammation, focusing on arachidonic acid, NF-κB, MAPK, PI3K/Akt, and JAK/STAT pathways. It investigates active compounds in herbal plants and their pharmacological characteristics. The review proposes a unique therapeutic blueprint for managing hepatic inflammation and diseases by modifying these pathways with herbal remedies.

Development of anti-cancer drugs for tumor-associated macrophages: a comprehensive review and mechanistic insights

This review provides an in-depth summary of the development of anti-cancer drugs for tumor-associated macrophages (TAMs), with a particular focus on the development and tissue specialization of macrophages, and factors influencing the polarization of M1 and M2 macrophages, and mechanistic insights underlying the targeting therapeutic approaches. TAMs, pivotal in the tumor microenvironment, exhibit notable plasticity and diverse functional roles. Influenced by the complex milieu, TAMs polarize into M1-type, which suppresses tumors, and M2-type, which promotes metastasis. Notably, targeting M2-TAMs is a promising strategy for tumor therapy. By emphasizing the importance of macrophages as a therapeutic target of anti-cancer drugs, this review aims to provide valuable insights and research directions for clinicians and researchers.

Targeting of TAMs: can we be more clever than cancer cells?

АBSTRACT: With increasing incidence and geography, cancer is one of the leading causes of death, reduced quality of life and disability worldwide. Principal progress in the development of new anticancer therapies, in improving the efficiency of immunotherapeutic tools, and in the personification of conventional therapies needs to consider cancer-specific and patient-specific programming of innate immunity. Intratumoral TAMs and their precursors, resident macrophages and monocytes, are principal regulators of tumor progression and therapy resistance. Our review summarizes the accumulated evidence for the subpopulations of TAMs and their increasing number of biomarkers, indicating their predictive value for the clinical parameters of carcinogenesis and therapy resistance, with a focus on solid cancers of non-infectious etiology. We present the state-of-the-art knowledge about the tumor-supporting functions of TAMs at all stages of tumor progression and highlight biomarkers, recently identified by single-cell and spatial analytical methods, that discriminate between tumor-promoting and tumor-inhibiting TAMs, where both subtypes express a combination of prototype M1 and M2 genes. Our review focuses on novel mechanisms involved in the crosstalk among epigenetic, signaling, transcriptional and metabolic pathways in TAMs. Particular attention has been given to the recently identified link between cancer cell metabolism and the epigenetic programming of TAMs by histone lactylation, which can be responsible for the unlimited protumoral programming of TAMs. Finally, we explain how TAMs interfere with currently used anticancer therapeutics and summarize the most advanced data from clinical trials, which we divide into four categories: inhibition of TAM survival and differentiation, inhibition of monocyte/TAM recruitment into tumors, functional reprogramming of TAMs, and genetic enhancement of macrophages.

A Small Molecule Antagonist of CX3CR1 (KAND567) Inhibited the Tumor Growth-Promoting Effect of Monocytes in Chronic Lymphocytic Leukemia (CLL)

BACKGROUND/OBJECTIVES

Nurse-like cells (NLCs) derived from monocytes in the tumor microenvironment support the growth of chronic lymphocytic leukemia (CLL) cells. Here, we investigated the effects of a CX3CR1 (fractalkine receptor) antagonist (KAND567) on autologous monocytes and their pro-survival effects on CLL cells in vitro.

METHODS

Plasma concentration of CX3CL1 was determined by ELISA and CX3CR1 expression by flow cytometry. CD19+ cells and autologous monocytes from patients with CLL and healthy donors were treated with KAND567 either in co-culture or alone. The apoptosis of CD19+ cells and monocytes was determined by Annexin V/PI staining and live-cell imaging.

RESULTS

Plasma concentration of CX3CL1 (fractalkine) was significantly higher in patients with CLL (n = 88) than in healthy donors (n = 32) (p < 0.0001), with higher levels in patients with active compared to non-active disease (p < 0.01). CX3CR1 was found on monocytes but not B cells in patients and controls. Levels of intermediate and non-classical CX3CR1+ monocytes were higher in patients with CLL than in controls (p < 0.001), particularly in those with active disease (p < 0.0001). Co-culture experiments revealed that autologous monocytes promoted the survival of both malignant and normal B cells and that KAND567 selectively inhibited the growth of CLL cells in a dose-dependent manner but only in the presence of autologous monocytes (p < 0.05). Additionally, KAND567 inhibited the transition of monocytes to NLCs in CLL (p < 0.05).

CONCLUSIONS

Our data suggest that the CX3CR1/CX3CL1 axis is activated in CLL and may contribute to the NLC-driven growth-promoting effects of CLL cells. KAND567, which is in clinical trials in other disorders, should also be explored in CLL.

Synthesis and preclinical evaluation of [18F]AlF-NODA-MP-C6-CTHRSSVVC as a PET tracer for CD163-positive tumor-infiltrating macrophages

Positron emission tomography (PET) can provide information about tumor-associated macrophage (TAM) infiltration, as long as a suitable tracer is available. This study aimed to evaluate the radiolabeled peptide [18F]AlF-NODA-MP-C6-CTHRSSVVC as a potential PET tracer for imaging of the CD163 receptor, which is expressed on M2-type tumor-associated macrophages. The conjugated peptide NODA-MP-C6-CTHRSSVVC was labeled with aluminum [18F]fluoride. Tracer binding and its biodistribution were evaluated in an in vitro binding assay and in healthy BALB/c mice, respectively. In addition, different treatments with cyclophosphamide in tumor-bearing mice were used to assess whether the tracer could detect differences in CD163 expression caused by differential TAM infiltration. After 7 days of treatment, animals were injected with [18F]AlF-NODA-MP-C6-CTHRSSVVC, and a 60-min dynamic PET scan was performed, followed by an ex vivo biodistribution study. [18F]AlF-NODA-MP-C6-CTHRSSVVC was prepared in 23 ± 6 % radiochemical yield and showed approximately 50 % of specific receptor-mediated binding in an in vitro binding assay on human CD163-expressing tissue homogenates. No CD163-mediated binding of [18F]AlF-NODA-MP-C6-CTHRSSVVC was detected by PET under normal physiological conditions in healthy BALB/c mice. On the other hand, CD163-positive xenograft tumors were clearly visualized with PET and a positive correlation was found between CD163 levels and the [18F]AlF-NODA-MP-C6-CTHRSSVVC tumor-to-muscle ratio (TMR) obtained from the PET images (Pearson r = 0.76, p = 0.002). No significant differences in the CD163 protein level and in the tracer uptake between treatment groups were found in the tumors. Taken together, [18F]AlF-NODA-MP-C6-CTHRSSVVC appears a promising candidate PET tracer for M2-type TAM, as it binds specifically to CD163 in vitro and its tumor uptake correlates well with CD163 expression in vivo.

An Immune-Enhancing Injectable Hydrogel Loaded with Esketamine and DDP Promotes Painless Immunochemotherapy to Inhibit Breast Cancer Growth

Chemotherapy is the cornerstone of triple-negative breast cancer. The poor effectiveness and severe neuropathic pain caused by it have a significant impact on the immune system. Studies confirmed that immune cells in the tumor microenvironment (TME), have critical roles in tumor immune regulation and prognosis. In this study, it is revealed that the painless administration of Esketamine, combined with Cisplatin (DDP), can exert an anti-tumor effect, which is further boosted by the hydrogel delivery system. It is also discovered that Esketamine combined with DDP co-loaded in Poloxamer Hydrogel (PDEH) induces local immunity by increasing mature Dendritic Cells (mDCs) and activated T cells in PDEH group while the regulatory T cells (Tregs) known as CD4+CD25+FoxP3+decreased significantly. Finally, , CD8+ and CD4+ T cells in the spleen exhibited a significant increase, suggesting a lasting immune impact of PDEH. This study proposes that Esketamine can serve as a painless immune modulator, enhancing an anti-tumor effect while co-loaded in poloxamer hydrogel with DDP. Along with improving immune cells in the microenvironment, it can potentially alleviate anxiety and depression. With its outstanding bio-safety profile, it offers promising new possibilities for painless clinical therapy.

Unleashing nanotechnology to redefine tumor-associated macrophage dynamics and non-coding RNA crosstalk in breast cancer

Breast cancer is a significant global health issue. Tumor-associated macrophages (TAMs) are crucial in influencing the tumor microenvironment and the progression of the disease. TAMs exhibit remarkable plasticity in adopting distinct phenotypes ranging from pro-inflammatory and anti-tumorigenic (M1-like) to immunosuppressive and tumor-promoting (M2-like). This review elucidates the multifaceted roles of TAMs in driving breast tumor growth, angiogenesis, invasion, and metastatic dissemination. Significantly, it highlights the intricate crosstalk between TAMs and non-coding RNAs (ncRNAs), including microRNAs, long noncoding RNAs, and circular RNAs, as a crucial regulatory mechanism modulating TAM polarization and functional dynamics that present potential therapeutic targets. Nanotechnology-based strategies are explored as a promising approach to reprogramming TAMs toward an anti-tumor phenotype. Various nanoparticle delivery systems have shown potential for modulating TAM polarization and inhibiting tumor-promoting effects. Notably, nanoparticles can deliver ncRNA therapeutics to TAMs, offering unique opportunities to modulate their polarization and activity.

Drug resistance and tumor immune microenvironment: An overview of current understandings (Review)

The use of antitumor drugs represents a reliable strategy for cancer therapy. Unfortunately, drug resistance has become increasingly common and contributes to tumor metastasis and local recurrence. The tumor immune microenvironment (TME) consists of immune cells, cytokines and immunomodulators, and collectively they influence the response to treatment. Epigenetic changes including DNA methylation and histone modification, as well as increased drug exportation have been reported to contribute to the development of drug resistance in cancers. In the past few years, the majority of studies on tumors have only focused on the development and progression of a tumor from a mechanistic standpoint; few studies have examined whether the changes in the TME can also affect tumor growth and drug resistance. Recently, emerging evidence have raised more concerns regarding the role of TME in the development of drug resistance. In the present review, it was discussed how the suppressive TME adapts to drug resistance characterized by the cooperation of immune cells, cytokines, immunomodulators, stromal cells and extracellular matrix. Furthermore, it was reviewed how these immunological or metabolic changes alter immuno‑surveillance and thus facilitate tumor drug resistance. In addition, potential targets present in the TME for developing novel therapeutic strategies to improve individualized therapy for cancer treatment were revealed.

YKL40/Integrin β4 Axis Induced by the Interaction between Cancer Cells and Tumor-Associated Macrophages Is Involved in the Progression of High-Grade Serous Ovarian Carcinoma

Macrophages in the tumor microenvironment, termed tumor-associated macrophages (TAMs), promote the progression of various cancer types. However, many mechanisms related to tumor-stromal interactions in epithelial ovarian cancer (EOC) progression remain unclear. High-grade serous ovarian carcinoma (HGSOC) is the most malignant EOC subtype. Herein, immunohistochemistry was performed on 65 HGSOC tissue samples, revealing that patients with a higher infiltration of CD68+, CD163+, and CD204+ macrophages had a poorer prognosis. We subsequently established an indirect co-culture system between macrophages and EOC cells, including HGSOC cells. The co-cultured macrophages showed increased expression of the TAM markers CD163 and CD204, and the co-cultured EOC cells exhibited enhanced proliferation, migration, and invasion. Cytokine array analysis revealed higher YKL40 secretion in the indirect co-culture system. The addition of YKL40 increased proliferation, migration, and invasion via extracellular signal-regulated kinase (Erk) signaling in EOC cells. The knockdown of integrin β4, one of the YKL40 receptors, suppressed YKL40-induced proliferation, migration, and invasion, as well as Erk phosphorylation in some EOC cells. Database analysis showed that high-level expression of YKL40 and integrin β4 correlated with a poor prognosis in patients with serous ovarian carcinoma. Therefore, the YKL40/integrin β4 axis may play a role in ovarian cancer progression.

Chemotherapy Enriches for Proinflammatory Macrophage Phenotypes that Support Cancer Stem-Like Cells and Disease Progression in Ovarian Cancer

High-grade serous ovarian cancer remains a poorly understood disease with a high mortality rate. Although most patients respond to cytotoxic therapies, a majority will experience recurrence. This may be due to a minority of drug-resistant cancer stem-like cells (CSC) that survive chemotherapy and are capable of repopulating heterogeneous tumors. It remains unclear how CSCs are supported in the tumor microenvironment (TME) particularly during chemotherapy exposure. Tumor-associated macrophages (TAM) make up half of the immune population of the ovarian TME and are known to support CSCs and contribute to cancer progression. TAMs are plastic cells that alter their phenotype in response to environmental stimuli and thus may influence CSC maintenance during chemotherapy. Given the plasticity of TAMs, we studied the effects of carboplatin on macrophage phenotypes using both THP1- and peripheral blood mononuclear cell (PBMC)-derived macrophages and whether this supports CSCs and ovarian cancer progression following treatment. We found that carboplatin exposure induces an M1-like proinflammatory phenotype that promotes SOX2 expression, spheroid formation, and CD117+ ovarian CSCs, and that macrophage-secreted CCL2/MCP-1 is at least partially responsible for this effect. Depletion of TAMs during carboplatin exposure results in fewer CSCs and prolonged survival in a xenograft model of ovarian cancer. This study supports a role for platinum-based chemotherapies in promoting a transient proinflammatory M1-like TAM that enriches for CSCs during treatment. Improving our understanding of TME responses to cytotoxic drugs and identifying novel mechanisms of CSC maintenance will enable the development of better therapeutic strategies for high-grade serous ovarian cancer. Significance: We show that chemotherapy enhances proinflammatory macrophage phenotypes that correlate with ovarian cancer progression. Given that macrophages are the most prominent immune cell within these tumors, this work provides the foundation for future translational studies targeting specific macrophage populations during chemotherapy, a promising approach to prevent relapse in ovarian cancer.

Platinum-based chemotherapy promotes antigen presenting potential in monocytes of patients with high-grade serous ovarian carcinoma

Ovarian cancer (OC) is the most lethal gynecologic malignancy worldwide. The major clinical challenge includes the asymptomatic state of the disease, making diagnosis possible only at advanced stages. Another OC complication is the high relapse rate and poor prognosis following the standard first-line treatment with platinum-based chemotherapy. At present, numerous clinical trials are being conducted focusing on immunotherapy in OC; nevertheless, there are still no FDA-approved indications. Personalized decision regarding the immunotherapy, including immune checkpoint blockade and immune cell-based immunotherapies, can depend on the effective antigen presentation required for the cytotoxic immune response. The major aim of our study was to uncover tumor-specific transcriptional and epigenetic changes in peripheral blood monocytes in patients with high-grade serous ovarian cancer (HGSOC). Another key point was to elucidate how chemotherapy can reprogram monocytes and how that relates to changes in other immune subpopulations in the blood. To this end, we performed single-cell RNA sequencing of peripheral blood mononuclear cells (PBMCs) from patients with HGSOC who underwent neoadjuvant chemotherapeutic treatment (NACT) and in treatment-naïve patients. Monocyte cluster was significantly affected by tumor-derived factors as well as by chemotherapeutic treatment. Bioinformatical analysis revealed three distinct monocyte subpopulations within PBMCs based on feature gene expression - CD14.Mn.S100A8.9hi, CD14.Mn.MHC2hi and CD16.Mn subsets. The intriguing result was that NACT induced antigen presentation in monocytes by the transcriptional upregulation of MHC class II molecules, but not by epigenetic changes. Increased MHC class II gene expression was a feature observed across all three monocyte subpopulations after chemotherapy. Our data also demonstrated that chemotherapy inhibited interferon-dependent signaling pathways, but activated some TGFb-related genes. Our results can enable personalized decision regarding the necessity to systemically re-educate immune cells to prime ovarian cancer to respond to anti-cancer therapy or to improve personalized prescription of existing immunotherapy in either combination with chemotherapy or a monotherapy regimen.

Advances on immunotherapy for osteosarcoma

Osteosarcoma is the most common primary bone cancer in children and young adults. Limited progress has been made in improving the survival outcomes in patients with osteosarcoma over the past four decades. Especially in metastatic or recurrent osteosarcoma, the survival rate is extremely unsatisfactory. The treatment of osteosarcoma urgently needs breakthroughs. In recent years, immunotherapy has achieved good therapeutic effects in various solid tumors. Due to the low immunogenicity and immunosuppressive microenvironment of osteosarcoma, immunotherapy has not yet been approved in osteosarcoma patients. However, immune-based therapies, including immune checkpoint inhibitors, chimeric antigen receptor T cells, and bispecfic antibodies are in active clinical development. In addition, other immunotherapy strategies including modified-NK cells/macrophages, DC vaccines, and cytokines are still in the early stages of research, but they will be hot topics for future study. In this review, we showed the functions of cell components including tumor-promoting and tumor-suppressing cells in the tumor microenvironment of osteosarcoma, and summarized the preclinical and clinical research results of various immunotherapy strategies in osteosarcoma, hoping to provide new ideas for future research in this field.

Spatiotemporal evolutionary process of osteosarcoma immune microenvironment remodeling and C1QBP-driven drug resistance deciphered through single-cell multi-dimensional analysis

The tumor immune microenvironment has manifested a crucial correlation with tumor occurrence, development, recurrence, and metastasis. To explore the mechanisms intrinsic to osteosarcoma (OS) initiation and progression, this study synthesizes multiple single-cell RNA sequencing data sets, constructing a comprehensive landscape of the OS microenvironment. Integrating single-cell RNA sequencing with bulk RNA sequencing data has enabled the identification of a significant correlation between heightened expression of the fatty acid metabolism-associated gene (C1QBP) and patient survival in OS. C1QBP not only amplifies the proliferation, migration, invasion, and anti-apoptotic properties of OS but also instigates cisplatin resistance. Subsequent investigations suggest that C1QBP potentially promotes macrophage polarization from monocytes/macrophages toward M2 and M3 phenotypes. Consequently, C1QBP may emerge as a novel target for modulating OS progression and resistance therapy.

Prognostic significance of the neutrophil to lymphocyte ratio in locally advanced breast cancer

The present study aimed to clarify the prognostic role of the pre-treatment neutrophil-to-lymphocyte ratio (NLR) for the response to neoadjuvant chemotherapy (NAC) in locally advanced breast cancer (LABC). Due to conflicting results in currently available data, the specific focus of the present study was on evaluating the associations between the pre-treatment NLR and the rate of achieving a pathological complete response (pCR) and survival outcomes. For the present study, data from a cohort of 465 consecutive patients with LABC who underwent NAC at King Feisal Specialist Hospital and Research Center (Riyadh, Saudi Arabia) between 2005 and 2014 were obtained from a prospective BC database and analyzed. Patients were stratified into two groups based on an optimal NLR cut-off determined using the receiver operating characteristic curve. Logistic regression analyses were conducted to assess variables associated with pCR, and Cox regression analyses were used to assess variables associated with survival outcomes. The low pre-treatment NLR group (≤2.2) was found to exhibit a higher likelihood of achieving a pCR (odds ratio, 2.59; 95% CI, 1.52-4.38; P<0.001), along with higher 5-year disease-free survival (DFS) [75.8 vs. 64.9%; hazard ratio (HR), 0.69; 95% CI, 0.50-0.94; P=0.02] and 5-year overall survival (OS; 90.3 vs. 81.9; HR, 0.62; 95% CI, 0.39-0.98; P=0.04) rates compared with those in the high NLR group (>2.2). Sub-group analysis revealed that the observed significance in survival outcomes was driven by the triple-negative BC (TNBC) subgroup. Patients with residual TNBC disease and a high pre-treatment NLR were observed to have lower 5-year DFS (44.4 vs. 75.0%; P=0.02) and 5-year OS (55.9 vs. 84.5%; P=0.055) rates compared with those with residual TNBC disease and a low NLR. To conclude, data from the present study suggest that the pre-treatment NLR can serve as a viable independent prognostic factor for pCR following NAC in patients with LABC and for survival outcomes, particularly for patients with TNBC.

Expanding horizons in cancer therapy by immunoconjugates targeting tumor microenvironments

Immunoconjugates are promising molecules combining antibodies with different agents, such as toxins, drugs, radionuclides, or cytokines that primarily aim to target tumor cells. However, tumor microenvironment (TME), which comprises a complex network of various cells and molecular cues guiding tumor growth and progression, remains a major challenge for effective cancer therapy. Our review underscores the pivotal role of TME in cancer therapy with immunoconjugates, examining the intricate interactions with TME and recent advancements in TME-targeted immunoconjugates. We explore strategies for targeting TME components, utilizing diverse antibodies such as neutralizing, immunomodulatory, immune checkpoint inhibitors, immunostimulatory, and bispecific antibodies. Additionally, we discuss different immunoconjugates, elucidating their mechanisms of action, advantages, limitations, and applications in cancer immunotherapy. Furthermore, we highlight emerging technologies enhancing the safety and efficacy of immunoconjugates, such as antibody engineering, combination therapies, and nanotechnology. Finally, we summarize current advancements, perspectives, and future developments of TME-targeted immunoconjugates.

Comprehensive integrated single-cell RNA sequencing analysis of brain metastasis and glioma microenvironment: Contrasting heterogeneity landscapes

Understanding the specific type of brain malignancy, source of brain metastasis, and underlying transformation mechanisms can help provide better treatment and less harm to patients. The tumor microenvironment plays a fundamental role in cancer progression and affects both primary and metastatic cancers. The use of single-cell RNA sequencing to gain insights into the heterogeneity profiles in the microenvironment of brain malignancies is useful for guiding treatment decisions. To comprehensively investigate the heterogeneity in gliomas and brain metastasis originating from different sources (lung and breast), we integrated data from three groups of single-cell RNA-sequencing datasets obtained from GEO. We gathered and processed single-cell RNA sequencing data from 90,168 cells obtained from 17 patients. We then employed the R package Seurat for dataset integration. Next, we clustered the data within the UMAP space and acquired differentially expressed genes for cell categorization. Our results underscore the significance of macrophages as abundant and pivotal constituents of gliomas. In contrast, lung-to-brain metastases exhibit elevated numbers of AT2, cytotoxic CD4+ T, and exhausted CD8+ T cells. Conversely, breast-to-brain metastases are characterized by an abundance of epithelial and myCAF cells. Our study not only illuminates the variation in the TME between brain metastasis with different origins but also opens the door to utilizing established markers for these cell types to differentiate primary brain metastatic cancers.

Single-cell resolution characterization of myeloid-derived cell states with implication in cancer outcome

Tumor-associated myeloid-derived cells (MDCs) significantly impact cancer prognosis and treatment responses due to their remarkable plasticity and tumorigenic behaviors. Here, we integrate single-cell RNA-sequencing data from different cancer types, identifying 29 MDC subpopulations within the tumor microenvironment. Our analysis reveals abnormally expanded MDC subpopulations across various tumors and distinguishes cell states that have often been grouped together, such as TREM2+ and FOLR2+ subpopulations. Using deconvolution approaches, we identify five subpopulations as independent prognostic markers, including states co-expressing TREM2 and PD-1, and FOLR2 and PDL-2. Additionally, TREM2 alone does not reliably predict cancer prognosis, as other TREM2+ macrophages show varied associations with prognosis depending on local cues. Validation in independent cohorts confirms that FOLR2-expressing macrophages correlate with poor clinical outcomes in ovarian and triple-negative breast cancers. This comprehensive MDC atlas offers valuable insights and a foundation for futher analyses, advancing strategies for treating solid cancers.

Macrophages as a Source and Target of GDF-15

Growth differentiation factor 15 (GDF-15) is a multifunctional cytokine that belongs to the transforming growth factor-beta (TGF-β) superfamily. GDF-15 is involved in immune tolerance and is elevated in several acute and chronic stress conditions, often correlating with disease severity and patient prognosis in cancer172 and metabolic and cardiovascular disorders. Despite these clinical associations, the molecular mechanisms orchestrating its effects remain to be elucidated. The effects of GDF-15 are pleiotropic but cell-specific and dependent on the microenvironment. While GDF-15 expression can be stimulated by inflammatory mediators, its predominant effects were reported as anti-inflammatory and pro-fibrotic. The role of GDF-15 in the macrophage system has been increasingly investigated in recent years. Macrophages produce high levels of GDF-15 during oxidative and lysosomal stress, which can lead to fibrogenesis and angiogenesis at the tissue level. At the same time, macrophages can respond to GDF-15 by switching their phenotype to a tolerogenic one. Several GDF-15-based therapies are under development, including GDF-15 analogs/mimetics and GDF-15-targeting monoclonal antibodies. In this review, we summarize the major physiological and pathological contexts in which GDF-15 interacts with macrophages. We also discuss the major challenges and future perspectives in the therapeutic translation of GDF-15.

Decoding the Intricate Landscape of Pancreatic Cancer: Insights into Tumor Biology, Microenvironment, and Therapeutic Interventions

Pancreatic ductal adenocarcinoma (PDAC) presents significant oncological challenges due to its aggressive nature and poor prognosis. The tumor microenvironment (TME) plays a critical role in progression and treatment resistance. Non-neoplastic cells, such as cancer-associated fibroblasts (CAFs) and tumor-associated macrophages (TAMs), contribute to tumor growth, angiogenesis, and immune evasion. Although immune cells infiltrate TME, tumor cells evade immune responses by secreting chemokines and expressing immune checkpoint inhibitors (ICIs). Vascular components, like endothelial cells and pericytes, stimulate angiogenesis to support tumor growth, while adipocytes secrete factors that promote cell growth, invasion, and treatment resistance. Additionally, perineural invasion, a characteristic feature of PDAC, contributes to local recurrence and poor prognosis. Moreover, key signaling pathways including Kirsten rat sarcoma viral oncogene (KRAS), transforming growth factor beta (TGF-β), Notch, hypoxia-inducible factor (HIF), and Wnt/β-catenin drive tumor progression and resistance. Targeting the TME is crucial for developing effective therapies, including strategies like inhibiting CAFs, modulating immune response, disrupting angiogenesis, and blocking neural cell interactions. A recent multi-omic approach has identified signature genes associated with anoikis resistance, which could serve as prognostic biomarkers and targets for personalized therapy.

Chemoresistance Mechanisms in Non-Small Cell Lung Cancer-Opportunities for Drug Repurposing

Globally, lung cancer contributes significantly to the public health burden-associated mortality. As this form of cancer is insidious in nature, there is an inevitable diagnostic delay leading to chronic tumor development. Non-small cell lung cancer (NSCLC) constitutes 80-85% of all lung cancer cases, making this neoplasia form a prevalent subset of lung carcinoma. One of the most vital aspects for proper diagnosis, prognosis, and adequate therapy is the precise classification of non-small cell lung cancer based on biomarker expression profiling. This form of biomarker profiling has provided opportunities for improvements in patient stratification, mechanistic insights, and probable druggable targets. However, numerous patients have exhibited numerous toxic side effects, tumor relapse, and development of therapy-based chemoresistance. As a result of these exacting situations, there is a dire need for efficient and effective new cancer therapeutics. De novo drug development approach is a costly and tedious endeavor, with an increased attrition rate, attributed, in part, to toxicity-related issues. Drug repurposing, on the other hand, when combined with computer-assisted systems biology approach, provides alternatives to the discovery of new, efficacious, and safe drugs. Therefore, in this review, we focus on a comparison of the conventional therapy-based chemoresistance mechanisms with the repurposed anti-cancer drugs from three different classes-anti-parasitic, anti-depressants, and anti-psychotics for cancer treatment with a primary focus on NSCLC therapeutics. Certainly, amalgamating these novel therapeutic approaches with that of the conventional drug regimen in NSCLC-affected patients will possibly complement/synergize the existing therapeutic modalities. This approach has tremendous translational significance, since it can combat drug resistance and cytotoxicity-based side effects and provides a relatively new strategy for possible application in therapy of individuals with NSCLC.

The Complex Tumor Microenvironment in Ovarian Cancer: Therapeutic Challenges and Opportunities

The tumor microenvironment (TME) in ovarian cancer (OC) has much greater complexity than previously understood. In response to aggressive pro-angiogenic stimulus, blood vessels form rapidly and are dysfunctional, resulting in poor perfusion, tissue hypoxia, and leakiness, which leads to increased interstitial fluid pressure (IFP). Decreased perfusion and high IFP significantly inhibit the uptake of therapies into the tumor. Within the TME, there are numerous inhibitor cells, such as myeloid-derived suppressor cells (MDSCs), tumor association macrophages (TAMs), regulatory T cells (Tregs), and cancer-associated fibroblasts (CAFs) that secrete high numbers of immunosuppressive cytokines. This immunosuppressive environment is thought to contribute to the lack of success of immunotherapies such as immune checkpoint inhibitor (ICI) treatment. This review discusses the components of the TME in OC, how these characteristics impede therapeutic efficacy, and some strategies to alleviate this inhibition.

Neutrophil extracellular traps modulate chemotherapy efficacy and its adverse side effects

Neutrophils, major regulator of innate immunity have recently emerged as key components of the tumor microenvironment. The role of neutrophils in cancer has been linked to their ability to form neutrophil extracellular traps (NETs), structures composed of decondensed DNA decorated with enzymes that are released into the extracellular space. Here, we discuss the pivotal roles of NETs, in influencing responses to chemotherapy and its severe adverse effect. Highlighting recent insights, we discuss the dual nature of NETs in the context of chemotherapy treatment, examining their potential to either counteract or enhance treatment outcomes. Strategic targeting of NETs emerges as a promising avenue for determining combination therapies that could help counteracting resistance or enhancing chemotherapy efficacy as well as limiting complications due to this type of treatment.

Targeting tumor‑associated macrophages: Critical players in tumor progression and therapeutic strategies (Review)

Tumor‑associated macrophages (TAMs) are essential components of the tumor microenvironment (TME) and display phenotypic heterogeneity and plasticity associated with the stimulation of bioactive molecules within the TME. TAMs predominantly exhibit tumor‑promoting phenotypes involved in tumor progression, such as tumor angiogenesis, metastasis, immunosuppression and resistance to therapies. In addition, TAMs have the potential to regulate the cytotoxic elimination and phagocytosis of cancer cells and interact with other immune cells to engage in the innate and adaptive immune systems. In this context, targeting TAMs has been a popular area of research in cancer therapy, and a comprehensive understanding of the complex role of TAMs in tumor progression and exploration of macrophage‑based therapeutic approaches are essential for future therapeutics against cancers. The present review provided a comprehensive and updated overview of the function of TAMs in tumor progression, summarized recent advances in TAM‑targeting therapeutic strategies and discussed the obstacles and perspectives of TAM‑targeting therapies for cancers.

Radiation Therapy and Myeloid-Derived Suppressor Cells: Breaking Down Their Cancerous Partnership

Radiation therapy (RT) has been a primary treatment modality in cancer for decades. Increasing evidence suggests that RT can induce an immunosuppressive shift via upregulation of cells such as tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs). MDSCs inhibit antitumor immunity through potent immunosuppressive mechanisms and have the potential to be crucial tools for cancer prognosis and treatment. MDSCs interact with many different pathways, desensitizing tumor tissue and interacting with tumor cells to promote therapeutic resistance. Vascular damage induced by RT triggers an inflammatory signaling cascade and potentiates hypoxia in the tumor microenvironment (TME). RT can also drastically modify cytokine and chemokine signaling in the TME to promote the accumulation of MDSCs. RT activation of the cGAS-STING cytosolic DNA sensing pathway recruits MDSCs through a CCR2-mediated mechanism, inhibiting the production of type 1 interferons and hampering antitumor activity and immune surveillance in the TME. The upregulation of hypoxia-inducible factor-1 and vascular endothelial growth factor mobilizes MDSCs to the TME. After recruitment, MDSCs promote immunosuppression by releasing reactive oxygen species and upregulating nitric oxide production through inducible nitric oxide synthase expression to inhibit cytotoxic activity. Overexpression of arginase-1 on subsets of MDSCs degrades L-arginine and downregulates CD3ζ, inhibiting T-cell receptor reactivity. This review explains how radiation promotes tumor resistance through activation of immunosuppressive MDSCs in the TME and discusses current research targeting MDSCs, which could serve as a promising clinical treatment strategy in the future.

Mitochondrial-Stem Cell Connection: Providing Additional Explanations for Understanding Cancer

The cancer paradigm is generally based on the somatic mutation model, asserting that cancer is a disease of genetic origin. The mitochondrial-stem cell connection (MSCC) proposes that tumorigenesis may result from an alteration of the mitochondria, specifically a chronic oxidative phosphorylation (OxPhos) insufficiency in stem cells, which forms cancer stem cells (CSCs) and leads to malignancy. Reviewed evidence suggests that the MSCC could provide a comprehensive understanding of all the different stages of cancer. The metabolism of cancer cells is altered (OxPhos insufficiency) and must be compensated by using the glycolysis and the glutaminolysis pathways, which are essential to their growth. The altered mitochondria regulate the tumor microenvironment, which is also necessary for cancer evolution. Therefore, the MSCC could help improve our understanding of tumorigenesis, metastases, the efficiency of standard treatments, and relapses.

Tumor-associated macrophages affect the treatment of lung cancer

As one of the most common malignant tumors in the world, lung cancer has limited benefits for patients despite its diverse treatment methods due to factors such as personalized medicine targeting histological type, immune checkpoint expression, and driver gene mutations. The high mortality rate of lung cancer is partly due to the immune-suppressive which limits the effectiveness of anti-cancer drugs and induces tumor cell resistance. The currently widely recognized TAM phenotypes include the anti-tumor M1 and pro-tumor M2 phenotypes. M2 macrophages promote the formation of an immune-suppressive microenvironment and hinder immune cell infiltration, thereby inhibiting activation of the anti-tumor immune system and aiding tumor cells in resisting treatment. Analyzing the relationship between different treatment methods and macrophages in the TME can help us better understand the impact of TAMs on lung cancer and confirm the feasibility of targeted TAM therapy. Targeting TAMs to reduce the M2/M1 ratio and reverse the immune-suppressive microenvironment can improve the clinical efficacy of conventional treatment methods and potentially open up more efficient combination treatment strategies, maximizing the benefit for lung cancer patients.

Macrophage diversity in human cancers: New insight provided by single-cell resolution and spatial context

M1/M2 paradigm of macrophage plasticity has existed for decades. Now it becomes clear that this dichotomy doesn't adequately reflect the diversity of macrophage phenotypes in tumor microenvironment (TME). Tumor-associated macrophages (TAMs) are a major population of innate immune cells in the TME that promotes tumor cell proliferation, angiogenesis and lymphangiogenesis, invasion and metastatic niche formation, as well as response to anti-tumor therapy. However, the fundamental restriction in therapeutic TAM targeting is the limited knowledge about the specific TAM states in distinct human cancer types. Here we summarized the results of the most recent studies that use advanced technologies (e.g. single-cell RNA sequencing and spatial transcriptomics) allowing to decipher novel functional subsets of TAMs in numerous human cancers. The transcriptomic profiles of these TAM subsets and their clinical significance were described. We emphasized the characteristics of specific TAM subpopulations - TREM2+, SPP1+, MARCO+, FOLR2+, SIGLEC1+, APOC1+, C1QC+, and others, which have been most extensively characterized in several cancers, and are associated with cancer prognosis. Spatial transcriptomics technologies defined specific spatial interactions between TAMs and other cell types, especially fibroblasts, in tumors. Spatial transcriptomics methods were also applied to identify markers of immunotherapy response, which are expressed by macrophages or in the macrophage-abundant regions. We highlighted the perspectives for novel techniques that utilize spatial and single cell resolution in investigating new ligand-receptor interactions for effective immunotherapy based on TAM-targeting.

Low molecular weight fucoidan LF2 improves the immunosuppressive tumor microenvironment and enhances the anti-pancreatic cancer activity of oxaliplatin

Chemotherapy remains the cornerstone of pancreatic cancer treatment. However, the dense interstitial and immunosuppressive microenvironment frequently render the ineffective anti-tumor activity of chemotherapeutic agents. Macrophages play a key role in the tumor immunomodulation. In this study, we found that low molecular weight of fucoidan (LF2) directly regulated the differentiation of mononuclear macrophages into the CD86+ M1 phenotype. LF2 significantly upregulated the expressions of M1 macrophage-specific cytokines, including iNOS, IL-6, TNFα and IL-12. LF2 modulated macrophage phenotypic transformation through activation of TLR4-NFκB pathway. Furthermore, we observed that LF2 enhanced the pro-apoptotic activity of oxaliplatin (OXA) in vitro by converting macrophages to a tumoricidal M1 phenotype. Meanwhile, LF2 increased intratumoral M1 macrophage infiltration and ameliorated the immunosuppressed tumor microenvironment, which in turn enhanced the anti-pancreatic ductal adenocarcinoma (PDAC) activity of OXA in vivo. Taken together, our results suggested that LF2 could act as a TLR4 agonist targeting macrophages and has a synergistic effect against PDAC when combined with OXA.

Impact of Chemotherapeutic Stress Depends on The Nature of Breast Cancer Spheroid and Induce Behavioral Plasticity to Resistant Population

Cellular or tumor dormancy, identified recently as one of the main reasons behind post-therapy recurrence, can be caused by diverse reasons. Chemotherapy has recently been recognized as one of such reasons. However, in-depth studies of chemotherapy-induced dormancy are lacking due to the absence of an in vitro human-relevant model tailor-made for such a scenario. This report utilized multicellular breast cancer spheroid to create a primary platform for establishing a chemotherapy-induced dormancy model. It is observed that extreme chemotherapeutic stress affects invasive and non-invasive spheroids differently. Non-invasive spheroids exhibit more resilience and maintain viability and migrational ability, while invasive spheroids display heightened susceptibility and improved tumorigenic capacity. Heterogenous spheroids exhibit increased tumorigenic capacity while show minimal survival ability. Further probing of chemotherapeutically dormant spheroids is needed to understand the molecular mechanism and identify dormancy-related markers to achieve therapeutic success in the future.

Tumor Microenvironment-Activatable Nanosystem Capable of Overcoming Multiple Therapeutic Obstacles for Augmenting Immuno/Metal-Ion Therapy

Abnormal tumor microenvironment (TME) imposes barriers to nanomedicine penetration into tumors and evolves tumor-supportive nature to provide tumor cell protection, seriously weakening the action of antitumor nanomedicines and posing significant challenges to their development. Here, we engineer a TME-activatable size-switchable core-satellite nanosystem (Mn-TI-Ag@HA) capable of increasing the effective dose of therapeutic agents in deep-seated tumors while reversing tumor-supportive microenvironment for augmenting immuno/metal-ion therapy. When activated by TME, the nanosystem disintegrates, allowing ultrasmall-sized Ag nanoparticles to become unbound and penetrate deep into solid tumors. Simultaneously, the nanosystem produces O2 and releases TGF-β inhibitors in situ to drive macrophage M2-to-M1 polarization, increasing intratumoral H2O2 concentration, and ultimately augmenting metal-ion therapy by accelerating hypertoxic Ag+ production. The nanosystem can overcome multiple obstacles that aid in tumor resistance to nanomedicine, demonstrating effective tumor penetration, TME regulation, and tumor inhibition effects. It can provoke long-term immunological memory effects against tumor rechallenge when combined with immune checkpoint inhibitor anti-PD-1. This work provides a paradigm for designing efficient antitumor nanomedicines.