Hypoxia as a driver of resistance to immunotherapy

A hypoxia-derived gene signature to suggest cisplatin-based therapeutic responses in patients with cervical cancer

Cervical cancer remains a significant global public health concern, often exhibits cisplatin resistance in clinical settings. Hypoxia, a characteristic of cervical cancer, substantially contributes to cisplatin resistance. To evaluate the therapeutic efficacy of cisplatin in patients with cervical cancer and to identify potential effective drugs against cisplatin resistance, we established a hypoxia-inducible factor-1 (HIF-1)-related risk score (HRRS) model using clinical data from patients treated with cisplatin. Cox and LASSO regression analyses were used to stratify patient risks and prognosis. Through qRT-PCR, we validated nine potential prognostic HIF-1 genes that successfully predict cisplatin responsiveness in patients and cell lines. Subsequently, we identified fostamatinib, an FDA-approved spleen tyrosine kinase inhibitor, as a promising drug for targeting the HRRS-high group. We observed a positive correlation between the IC50 values of fostamatinib and HRRS in cervical cancer cell lines. Moreover, fostamatinib exhibited potent anticancer effects on high HRRS groups in vitro and in vivo. In summary, we developed a hypoxia-related gene signature that suggests cisplatin response prediction in cervical cancer and identified fostamatinib as a potential novel treatment approach for resistant cases.

MTHFD2-mediated redox homeostasis promotes gastric cancer progression under hypoxic conditions

OBJECTIVES

Cancer cells undergo metabolic reprogramming to adapt to high oxidative stress, but little is known about how metabolic remodeling enables gastric cancer cells to survive stress associated with aberrant reactive oxygen species (ROS) production. Here, we aimed to identify the key metabolic enzymes that protect gastric cancer (GC) cells from oxidative stress.

METHODS

ROS level was detected by DCFH-DA probes. Multiple cell biological studies were performed to identify the underlying mechanisms. Furthermore, cell-based xenograft and patient-derived xenograft (PDX) model were performed to evaluate the role of MTHFD2 in vivo.

RESULTS

We found that overexpression of MTHFD2, but not MTHFD1, is associated with reduced overall and disease-free survival in gastric cancer. In addition, MTHFD2 knockdown reduces the cellular NADPH/NADP+ ratio, colony formation and mitochondrial function, increases cellular ROS and cleaved PARP levels and induces in cell death under hypoxia, a hallmark of solid cancers and a common inducer of oxidative stress. Moreover, genetic or pharmacological inhibition of MTHFD2 reduces tumor burden in both tumor cell lines and patient-derived xenograft-based models.

DISCUSSION

our study highlights the crucial role of MTHFD2 in redox regulation and tumor progression, demonstrating the therapeutic potential of targeting MTHFD2.

Pharmacologic ascorbate induces transient hypoxia sensitizing pancreatic ductal adenocarcinoma to a hypoxia activated prodrug

Hypoxic tumor microenvironments pose a significant challenge in cancer treatment. Hypoxia-activated prodrugs like evofosfamide aim to specifically target and eliminate these resistant cells. However, their effectiveness is often limited by reoxygenation after cell death. We hypothesized that ascorbate's pro-oxidant properties could be harnessed to induce transient hypoxia, enhancing the efficacy of evofosfamide by overcoming reoxygenation. To test this hypothesis, we investigated the sensitivity of MIA Paca-2 and A549 cancer cells to ascorbate in vitro and in vivo. Ascorbate induced a cytotoxic effect at 5 mM that could be alleviated by endogenous administration of catalase, suggesting a role for hydrogen peroxide in its cytotoxic mechanism. In vitro, Seahorse experiments indicated that the generation of hydrogen peroxide consumes oxygen, which is offset at later time points by a reduction in oxygen consumption due to hydrogen peroxide's cytotoxic effect. In vivo, photoacoustic imaging showed pharmacologic ascorbate treatment at sublethal levels triggered a complex, multi-phasic response in tumor oxygenation across both cell lines. Initially, ascorbate generated transient hypoxia within minutes through hydrogen peroxide production, via reactions that consume oxygen. This initial hypoxic phase peaked at around 150 s and then gradually subsided. However, at longer time scales (approximately 300 s) a vasodilation effect triggered by ascorbate resulted in increased blood flow and subsequent reoxygenation. Combining sublethal levels of i. p. Ascorbate with evofosfamide significantly prolonged tumor doubling time in MIA Paca-2 and A549 xenografts compared to either treatment alone. This improvement, however, was only observed in a subpopulation of tumors, highlighting the complexity of the oxygenation response.

Hypoxia-associated markers in the prognosis of oral canine melanoma

Canine oral malignant melanoma (COMM) is the most common neoplasm in the oral cavity characterized by local invasiveness and high metastatic potential. Hypoxia represents a crucial feature of the solid tumor microenvironment promoting cancer progression and drug resistance. Hypoxia-inducible factor-1α (HIF-1α) and its downstream effectors, vascular endothelial growth factor A (VEGF-A), glucose transporter isoform 1 (GLUT1), C-X-C chemokine receptor type 4 (CXCR4), and carbonic anhydrase IX (CAIX), are the main regulators of the adaptive response to low oxygen availability. The prognostic value of these markers was evaluated in 36 COMMs using immunohistochemistry. In addition, the effects of cobalt chloride-mediated hypoxia were evaluated in 1 primary COMM cell line. HIF-1α expression was observed in the nucleus, and this localization correlated with the presence or enhanced expression of HIF-1α-regulated genes at the protein level. Multivariate analysis revealed that in dogs given chondroitin sulfate proteoglycan-4 (CSPG4) DNA vaccine, COMMs expressing HIF-1α, VEGF-A, and CXCR4 were associated with shorter disease-free intervals (DFI) compared with tumors that were negative for these markers (P = .03), suggesting hypoxia can influence immunotherapy response. Western blotting showed that, under chemically induced hypoxia, COMM cells accumulate HIF-1α and smaller amounts of CAIX. HIF-1α induction and stabilization triggered by hypoxia was corroborated by immunofluorescence, showing its nuclear translocation. These findings reinforce the role of an hypoxic microenvironment in tumor progression and patient outcome in COMM, as previously established in several human and canine cancers. In addition, hypoxic markers may represent promising prognostic markers, highlighting opportunities for their use in therapeutic strategies for COMMs.

Optimizing the spatial immune landscape of CD103+CD8+ tissue-resident memory T cells in non-small cell lung cancer by neoadjuvant chemotherapy

BACKGROUND

Neoadjuvant chemotherapy (NAC) combined with immunotherapy is increasingly used in non-small cell lung cancer (NSCLC). Tissue-resident memory T (TRM) cells are the primary subset responding to anti-cancer immunity. However, the immunomodulatory effects of NAC on TRM cells remain unknown.

METHODS

We established two NSCLC cohorts including patients undergoing upfront surgery (US) and NAC followed by surgery. Beyond the unpaired comparison between the US cohort (n = 122) and NAC cohort (n = 141) with resection samples, 58 matched pre-NAC biopsy samples were available for paired comparisons. Using multiplex immunofluorescence, we characterized TRM cells (CD103+CD8+) and four heterogeneous TRM subsets, including naive TRM1 (PD-1-Tim-3-), pre-exhausted TRM2 (PD-1+Tim-3-), TRM3 (PD-1-Tim-3+), and terminally exhausted TRM4 (PD-1+Tim-3+). Cell density, cytotoxicity, and two spatial features were defined to evaluate the effect of NAC on TRM subsets.

RESULTS

The cell densities, infiltration scores, and cancer-cell proximity scores of TRM cells, especially TRM1&2 subsets, were significantly increased after NAC and associated with better prognosis of patients. In Contrast, no significant change was observed in the TRM4 subset, which was associated with poor prognosis. Besides, the cytotoxicity of TRM subsets was unaltered after NAC. Compared with patients without major pathologic response (MPRs), patients with MPR had higher densities of TRM1&2 subsets and higher cancer-cell proximity scores of TRM2&3 subsets. Furthermore, increased density of CD31 + cancer microvessels was positively associated with both TRM and Tnon-RM cells after NAC.

CONCLUSIONS

NAC may remodel the cell density and spatial distribution of TRM subsets, which is associated with favorable therapeutic effect and prognosis in patients with NSCLC.

Harnessing and Mimicking Bacterial Features to Combat Cancer: From Living Entities to Artificial Mimicking Systems

Bacterial-derived micro-/nanomedicine has garnered considerable attention in anticancer therapy, owing to the unique natural features of bacteria, including specific targeting ability, immunogenic benefits, physicochemical modifiability, and biotechnological editability. Besides, bacterial components have also been explored as promising drug delivery vehicles. Harnessing these bacterial features, cutting-edge physicochemical and biotechnologies have been applied to attenuated tumor-targeting bacteria with unique properties or functions for potent and effective cancer treatment, including strategies of gene-editing and genetic circuits. Further, the advent of bacteria-inspired micro-/nanorobots and mimicking artificial systems has furnished fresh perspectives for formulating strategies for developing highly efficient drug delivery systems. Focusing on the unique natural features and advantages of bacteria, this review delves into advances in bacteria-derived drug delivery systems for anticancer treatment in recent years, which has experienced a process from living entities to artificial mimicking systems. Meanwhile, a summary of relative clinical trials is provided and primary challenges impeding their clinical application are discussed. Furthermore, future directions are suggested for bacteria-derived systems to combat cancer.

Hypoxia-responsive lncRNA MIR155HG promotes PD-L1 expression in hepatocellular carcinoma cells by enhancing HIF-1α mRNA stability

The microenvironment of hepatocellular carcinoma (HCC) is characterized by hypoxia, which leads to immune evasion of HCC. Therefore, gaining a comprehensive understanding of the mechanism underlying the impact of hypoxia on HCC cells may provide valuable insights into immune checkpoint therapy. Based on analysis of databases and clinical samples, we observed that expression level of programmed cell death ligand 1 (PD-L1) and long non-coding RNA (lncRNA) MIR155HG in patients in the hypoxia group were higher than those in the non-hypoxia group. Furthermore, there was a positive correlation between the expression of PD-L1 and MIR155HG with that of HIF-1α. In vitro experiments using hypoxic treatment demonstrated an increase in PD-L1 and MIR155HG expression levels in HCC cells. While the hypoxia-induced upregulation of PD-L1 could be reversed by knocking down MIR155HG. Mechanistically, as a transcription factor, HIF-1α binds to the promoter region of MIR155HG to enhance its transcriptional activity under hypoxic conditions. Hypoxia acts as a stressor promoting nuclear output of ILF3 leading to increased binding of ILF3 to MIR155HG, thereby enhancing stability for HIF-1α mRNA. In vivo, knocking down MIR155HG inhibit subcutaneous tumor growth, reduce the expression of HIF-1α and PD-L1 within tumors; additionally, it enhances anti-tumor immunity response. These findings suggested that through inducing MIR155HG to interact with ILF3, hypoxia increases HIF-1α mRNA stability resulting in elevated PD-L1 expression in HCC and thus promoting immune escape. In summary, this study provides new insights into the effects of hypoxia on HCC immunosuppression.

The Immune Landscape of Pheochromocytoma and Paraganglioma: Current Advances and Perspectives

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors derived from neural crest cells from adrenal medullary chromaffin tissues and extra-adrenal paraganglia, respectively. Although the current treatment for PPGLs is surgery, optimal treatment options for advanced and metastatic cases have been limited. Hence, understanding the role of the immune system in PPGL tumorigenesis can provide essential knowledge for the development of better therapeutic and tumor management strategies, especially for those with advanced and metastatic PPGLs. The first part of this review outlines the fundamental principles of the immune system and tumor microenvironment, and their role in cancer immunoediting, particularly emphasizing PPGLs. We focus on how the unique pathophysiology of PPGLs, such as their high molecular, biochemical, and imaging heterogeneity and production of several oncometabolites, creates a tumor-specific microenvironment and immunologically "cold" tumors. Thereafter, we discuss recently published studies related to the reclustering of PPGLs based on their immune signature. The second part of this review discusses future perspectives in PPGL management, including immunodiagnostic and promising immunotherapeutic approaches for converting "cold" tumors into immunologically active or "hot" tumors known for their better immunotherapy response and patient outcomes. Special emphasis is placed on potent immune-related imaging strategies and immune signatures that could be used for the reclassification, prognostication, and management of these tumors to improve patient care and prognosis. Furthermore, we introduce currently available immunotherapies and their possible combinations with other available therapies as an emerging treatment for PPGLs that targets hostile tumor environments.

Hypoxia inhibits the iMo/cDC2/CD8+ TRMs immune axis in the tumor microenvironment of human esophageal cancer

BACKGROUND

Esophageal cancer (ESCA) is a form of malignant tumor associated with chronic inflammation and immune dysregulation. However, the specific immune status and key mechanisms of immune regulation in this disease require further exploration.

METHODS

To investigate the features of the human ESCA tumor immune microenvironment and its possible regulation, we performed mass cytometry by time of flight, single-cell RNA sequencing, multicolor fluorescence staining of tissue, and flow cytometry analyses on tumor and paracancerous tissue from treatment-naïve patients.

RESULTS

We depicted the immune landscape of the ESCA and revealed that CD8+ (tissue-resident memory CD8+ T cells (CD8+ TRMs) were closely related to disease progression. We also revealed the heterogeneity of CD8+ TRMs in the ESCA tumor microenvironment (TME), which was associated with their differentiation and function. Moreover, the subset of CD8+ TRMs in tumor (called tTRMs) that expressed high levels of granzyme B and immune checkpoints was markedly decreased in the TME of advanced ESCA. We showed that tTRMs are tumor effector cells preactivated in the TME. We then demonstrated that conventional dendritic cells (cDC2s) derived from intermediate monocytes (iMos) are essential for maintaining the proliferation of CD8+ TRMs in the TME. Our preliminary study showed that hypoxia can promote the apoptosis of iMos and impede the maturation of cDC2s, which in turn reduces the proliferative capacity of CD8+ TRMs, thereby contributing to the progression of cancer.

CONCLUSIONS

Our study revealed the essential antitumor roles of CD8+ TRMs and preliminarily explored the regulation of the iMo/cDC2/CD8+ TRM immune axis in the human ESCA TME.

Novel hypoxia- and lactate metabolism-related molecular subtyping and prognostic signature for colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is a serious global health burden because of its high morbidity and mortality rates. Hypoxia and massive lactate production are hallmarks of the CRC microenvironment. However, the effects of hypoxia and lactate metabolism on CRC have not been fully elucidated. This study aimed to develop a novel molecular subtyping based on hypoxia-related genes (HRGs) and lactate metabolism-related genes (LMRGs) and construct a signature to predict the prognosis of patients with CRC and treatment efficacy.

METHODS

Bulk and single-cell RNA-sequencing and clinical data of CRC were downloaded from the TCGA and GEO databases. HRGs and LMRGs were obtained from the Molecular Signatures Database. The R software package DESeq2 was used to perform differential expression analysis. Molecular subtyping was performed using unsupervised clustering. A predictive signature was developed using univariate Cox regression, random forest model, LASSO, and multivariate Cox regression analyses. Finally, the sensitivity of tumor cells to chemotherapeutic agents before and after hypoxia was verified using in vitro experiments.

RESULTS

We classified 575 patients with CRC into three molecular subtypes and were able to distinguish their prognoses clearly. The C1 subtype, which exhibits high levels of hypoxia, has a low proportion of CD8 + T cells and a high proportion of macrophages. The expression of immune checkpoint genes is generally elevated in C1 patients with severe immune dysfunction. Subsequently, we constructed a predictive model, the HLM score, which effectively predicts the prognosis of patients with CRC and the efficacy of immunotherapy. The HLM score was validated in GSE39582, GSE106584, GSE17536, and IMvigor210 datasets. Patients with high HLM scores exhibit high infiltration of CD8 + exhausted T cells (Tex), especially terminal Tex, and oxidative phosphorylation (OXPHOS)-Tex in the immune microenvironment. Finally, in vitro experiments confirmed that CRC cell lines were less sensitive to 5-fluorouracil, oxaliplatin, and irinotecan under hypoxic conditions.

CONCLUSION

We constructed novel hypoxia- and lactate metabolism-related molecular subtypes and revealed their immunological and genetic characteristics. We also developed an HLM scoring system that could be used to predict the prognosis and efficacy of immunotherapy in patients with CRC.

The cellular-centered view of hypoxia tumor microenvironment: Molecular mechanisms and therapeutic interventions

Cancer is a profoundly dynamic, heterogeneous and aggressive systemic ailment, with a coordinated evolution of various types of tumor niches. Hypoxia plays an indispensable role in the tumor micro-ecosystem, drastically enhancing the plasticity of cancer cells, fibroblasts and immune cells and orchestrating intercellular communication. Hypoxia-induced signals, particularly hypoxia-inducible factor-1α (HIF-1α), drive the reprogramming of genetic, transcriptional, and proteomic profiles. This leads to a spectrum of interconnected processes, including augmented survival of cancer cells, evasion of immune surveillance, metabolic reprogramming, remodeling of the extracellular matrix, and the development of resistance to conventional therapeutic modalities like radiotherapy and chemotherapy. Here, we summarize the latest research on the multifaceted effects of hypoxia, where a multitude of cellular and non-cellular elements crosstalk with each other and co-evolve in a synergistic manner. Additionally, we investigate therapeutic approaches targeting hypoxic niche, encompassing hypoxia-activated prodrugs, HIF inhibitors, nanomedicines, and combination therapies. Finally, we discuss some of the issues to be addressed and highlight the potential of emerging technologies in the treatment of cancer.

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.

MRI-guided dynamic risk assessment in cervical cancer based on tumor hypoxia at diagnosis and volume response at brachytherapy

BACKGROUND AND PURPOSE

Improvements in treatment outcome for patients with locally advanced cervical cancer (LACC) require a better classification of patients according to their risk of recurrence. We investigated whether an imaging-based approach, combining pretreatment hypoxia and tumor response during therapy, could improve risk classification.

MATERIAL AND METHODS

Ninety-three LACC patients with T2-weigthed (T2W)-, dynamic contrast enhanced (DCE)- and diffusion weighted (DW)-magnetic resonance (MR) images acquired before treatment, and T2W- and, for 64 patients, DW-MR images, acquired at brachytherapy, were collected. Pretreatment hypoxic fraction (HFpre) was determined from DCE- and DW-MR images using the consumption and supply-based hypoxia (CSH)-imaging method. Volume regression at brachytherapy was assessed from T2W-MR images and combined with HFpre. In 17 patients with adequate DW-MR images at brachytherapy, the apparent diffusion coefficient (ADC), reflecting tumor cell density, was calculated. Change in ADC during therapy was combined with volume regression yielding functional regression as explorative response measure. Endpoint was disease free survival (DFS).

RESULTS

HFpre was the strongest predictor of DFS, but a significant correlation with outcome was found also for volume regression. The combination of HFpre and volume regression showed a stronger association with DFS than HFpre alone. Patients with disease recurrence were selected to either the intermediate- or high-risk group with a 100 % accuracy. Functional regression showed a stronger correlation to HFpre than volume regression.

CONCLUSION

The combination of pretreatment hypoxia and volume regression at brachytherapy improved patient risk classification. Integration of ADC with volume regression showed promise as a new tumor response parameter.

Cancer-associated fibroblasts in pancreatic ductal adenocarcinoma therapy: Challenges and opportunities

Pancreatic ductal adenocarcinoma (PDAC) is a solid organ malignancy with a high mortality rate. Statistics indicate that its incidence has been increasing as well as the associated deaths. Most patients with PDAC show poor response to therapies making the clinical management of this cancer difficult. Stromal cells in the tumor microenvironment (TME) contribute to the development of resistance to therapy in PDAC cancer cells. Cancer-associated fibroblasts (CAFs), the most prevalent stromal cells in the TME, promote a desmoplastic response, produce extracellular matrix proteins and cytokines, and directly influence the biological behavior of cancer cells. These multifaceted effects make it difficult to eradicate tumor cells from the body. As a result, CAF-targeting synergistic therapeutic strategies have gained increasing attention in recent years. However, due to the substantial heterogeneity in CAF origin, definition, and function, as well as high plasticity, majority of the available CAF-targeting therapeutic approaches are not effective, and in some cases, they exacerbate disease progression. This review primarily elucidates on the effect of CAFs on therapeutic efficiency of various treatment modalities, including chemotherapy, radiotherapy, immunotherapy, and targeted therapy. Strategies for CAF targeting therapies are also discussed.

Nanomedicine Remodels Tumor Microenvironment for Solid Tumor Immunotherapy

Although immunotherapy is relatively effective in treating hematological malignancies, their efficacy against solid tumors is still suboptimal or even noneffective presently. Compared to hematological cancers, solid tumors exhibit strikingly different immunosuppressive microenvironment, severely deteriorating the efficacy of immunotherapy: (1) chemical features such as hypoxia and mild acidity suppress the activity of immune cells, (2) the pro-tumorigenic domestication of immune cells in the microenvironment within the solid tumors further undermines the effectiveness of immunotherapy, and (3) the dense physical barrier of solid tumor tissues prevents the effective intratumoral infiltration and contact killing of active immune cells. Therefore, we believe that reversing the immunosuppressive microenvironment are of critical priority for the immunotherapy against solid tumors. Due to their unique morphologies, structures, and compositions, nanomedicines have become powerful tools for achieving this goal. In this Perspective, we will first briefly introduce the immunosuppressive microenvironment of solid tumors and then summarize the most recent progresses in nanomedicine-based immunotherapy for solid tumors by remodeling tumor immune-microenvironment in a comprehensive manner. It is highly expected that this Perspective will aid in advancing immunotherapy against solid tumors, and we are highly optimistic on the future development in this burgeoning field.

Identification of a novel cancer-associated fibroblasts gene signature based on bioinformatics analysis to predict prognosis and therapeutic responses in breast cancer

Cancer-associated fibroblasts (CAFs) provide suitable conditions for growth of tumor cell and facilitate tumor progression. Hence, we aimed to identify a CAFs-related gene signature associated with the prognosis of patients with breast cancer (BRCA). We downloaded datasets from Gene Expression Omnibus (GEO) and confirmed the correlation between CAFs infiltration scores and prognosis. By performing weighted gene co-expression network analysis (WGCNA) and Lasso Cox regression analysis, we constructed a four-gene (COL5A3, FN1, POSTN, and RARRES2) prognostic CAFs signature model. Based on the median risk score of CAFs, patients with BRCA were divided into high- and low-risk groups. Compared with low-risk group, patients in high-risk group exhibited a poor prognosis and limited response to immunotherapy. Furthermore, patients with high CAFs risk scores were found to have a detrimental prognosis due to the induction of immunosuppressive cell infiltration, resulting in an immunosuppressive tumor microenvironment. Importantly, we found that CAFs overexpressing FN1 and POSTN significantly promoted the wound healing and invasion ability of tumor cells in vitro validation. Taking together, we identified a four-gene prognostic CAFs signature, which was proven to be a reliable indicator for prognosis and therapeutic efficacy in patients with BRCA. This study provided evidence for novel CAFs-based stromal therapy.

Nanocarriers address intracellular barriers for efficient drug delivery, overcoming drug resistance, subcellular targeting and controlled release

The cellular barriers are major bottlenecks for bioactive compounds entering into cells to accomplish their biological functions, which limits their biomedical applications. Nanocarriers have demonstrated high potential and benefits for encapsulating bioactive compounds and efficiently delivering them into target cells by overcoming a cascade of intracellular barriers to achieve desirable therapeutic and diagnostic effects. In this review, we introduce the cellular barriers ahead of drug delivery and nanocarriers, as well as summarize recent advances and strategies of nanocarriers for increasing internalization with cells, promoting intracellular trafficking, overcoming drug resistance, targeting subcellular locations and controlled drug release. Lastly, the future perspectives of nanocarriers for intracellular drug delivery are discussed, which mainly focus on potential challenges and future directions. Our review presents an overview of intracellular drug delivery by nanocarriers, which may encourage the future development of nanocarriers for efficient and precision drug delivery into a wide range of cells and subcellular targets.

Enhancing photodynamic immunotherapy by reprograming the immunosuppressive tumor microenvironment with hypoxia relief

Tumor hypoxia impairs the generation of reactive oxygen species and the induction of immunogenic cell death (ICD) for photodynamic therapy (PDT), thus impeding its efficacy and the subsequent immunotherapy. In addition, hypoxia plays a critical role in forming immunosuppressive tumor microenvironments (TME) by regulating the infiltration of immunosuppressive tumor-associated macrophages (TAMs) and the expression of programmed death ligand 1 (PD-L1). To simultaneously tackle these issues, a MnO2-containing albumin nanoplatform co-delivering IR780, NLG919, and a paclitaxel (PTX) dimer is designed to boost photodynamic immunotherapy. The MnO2-catalyzed oxygen supply bolsters the efficacy of PDT and PTX-mediated chemotherapy, collectively amplifying the induction of ICD and the expansion of tumor-specific cytotoxic T lymphocytes (CTLs). More importantly, hypoxia releif reshapes the immunosuppressive TME via down-regulating the intratumoral infiltration of M2-type TAMs and the PD-L1 expression of tumor cells to enhance the infiltration and efficacy of CTLs in combination with immune checkpoint blockade (ICB) by NLG919, consequently eradicating primary tumors and almost completely preventing tumor relapse and metastasis. This study sets an example of enhanced immunotherapy for breast cancers through dual ICD induction and simultaneous immunosuppression modulation via both hypoxia relief and ICB, providing a strategy for the treatment of other hypoxic and immunosuppressive cancers.

High expression of B7-H3 on monocyte/macrophages in tumor microenvironment promotes lung cancer progression by inhibiting apoptosis

Monocyte/macrophages constitute a significant population of tumor-infiltrating immune cells and play a crucial role in tumor growth, invasion, and metastasis. B7-H3, has immune regulatory functions, however, it is unclear whether B7-H3 expressed on monocyte/macrophages plays a significance role in tumor progression. We found B7-H3 was high-expressed on monocyte/macrophages in tumor microenvironment compared with adjacent tissues in lung cancer, and its expression level was positively correlated with the number of monocyte/macrophages. Furthermore, the expression of B7-H3 was related to clinical stage and lymph node metastasis. Moreover, miR-29a-3p negatively regulated B7-H3, and the expression of B7-H3 on THP-1-derived macrophages was regulated by secreting exosomes containing miR-29a-3p. In addition, knockdown of B7-H3 promoted macrophage apoptosis under hypoxia. Mechanistically, B7-H3 enhanced the antiapoptotic ability of macrophage by up-regulating HIF-1ɑ via activating NF-κB. Taken together, these results imply that B7-H3 as a therapeutic target could hold promise for enhancing anti-tumor immune responses in individuals diagnosed with lung cancer.

Tumor Microenvironment Modulating CaCO3 -Based Colloidosomal Microreactors Can Generally Reinforce Cancer Immunotherapy

Tumor hypoxia and acidity, two general features of solid tumors, are known to have negative effect on cancer immunotherapy by directly causing dysfunction of effector immune cells and promoting suppressive immune cells inside tumors. Herein, a multifunctional colloidosomal microreactor is constructed by encapsulating catalase within calcium carbonate (CaCO3 ) nanoparticle-assembled colloidosomes (abbreviated as CaP CSs) via the classic double emulsion method. The yielded CCaP CSs exhibit well-retained proton-scavenging and hydrogen peroxide decomposition performances and can thus neutralize tumor acidity, attenuate tumor hypoxia, and suppress lactate production upon intratumoral administration. Consequently, CCaP CSs treatment can activate potent antitumor immunity and thus significantly enhance the therapeutic potency of coloaded anti-programmed death-1 (anti-PD-1) antibodies in both murine subcutaneous CT26 and orthotopic 4T1 tumor xenografts. In addition, such CCaP CSs treatment also markedly reinforces the therapeutic potency of epidermal growth factor receptor expressing chimeric antigen receptor T (EGFR-CAR-T) cells toward a human triple-negative breast cancer xenograft by promoting their tumor infiltration and effector cytokine secretion. Therefore, this study highlights that chemical modulation of tumor acidity and hypoxia can collectively reverse tumor immunosuppression and thus significantly potentiate both immune checkpoint blockade and CAR-T cell immunotherapies toward solid tumors.

Current advances in modulating tumor hypoxia for enhanced therapeutic efficacy

Hypoxia is a common feature of most solid tumors, which promotes the proliferation, invasion, metastasis, and therapeutic resistance of tumors. Researchers have been developing advanced strategies and nanoplatforms to modulate tumor hypoxia to enhance therapeutic effects. A timely review of this rapidly developing research topic is therefore highly desirable. For this purpose, this review first introduces the impact of hypoxia on tumor development and therapeutic resistance in detail. Current developments in the construction of various nanoplatforms to enhance tumor treatment in response to hypoxia are also systematically summarized, including hypoxia-overcoming, hypoxia-exploiting, and hypoxia-disregarding strategies. We provide a detailed discussion of the rationale and research progress of these strategies. Through a review of current trends, it is hoped that this comprehensive overview can provide new prospects for clinical application in tumor treatment. STATEMENT OF SIGNIFICANCE: As a common feature of most solid tumors, hypoxia significantly promotes tumor progression. Advanced nanoplatforms have been developed to modulate tumor hypoxia to enhanced therapeutic effects. In this review, we first introduce the impact of hypoxia on tumor progression. Current developments in the construction of various nanoplatforms to enhance tumor treatment in response to hypoxia are systematically summarized, including hypoxia-overcoming, hypoxia-exploiting, and hypoxia-disregarding strategies. We discuss the rationale and research progress of the above strategies in detail, and finally introduce future challenges for treatment of hypoxic tumors. By reviewing the current trends, this comprehensive overview can provide new prospects for clinical translatable tumor therapy.

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.

Therapeutic effects and underlying mechanism of poly (L-glutamic acid)-g-methoxy poly (ethylene glycol)/combretastatin A4/BLZ945 nanoparticles on Renca renal carcinoma

Introduction: The prognosis of advanced renal carcinoma is not ideal, necessitating the exploration of novel treatment strategies. Poly(L-glutamic acid)-g-methoxy poly(ethylene glycol)/Combretastatin A4 (CA4)/BLZ945 nanoparticles (CB-NPs) possess the dual capability of CA4 (targeting blood vessels to induce tumor necrosis) and BLZ945 (inducing M2 macrophage apoptosis), thereby inhibiting tumor growth. Methods: Here, the therapeutic effects and underlying mechanism was explored by CCK-8 cytotoxicity experiment, transwell cell invasion and migration experiment, H&E, western blot analysis, immunohistochemistry, flow cytometry, and other techniques. Results: These results demonstrated that CB-NPs could inhibit the growth of Renca cells and subcutaneous tumors in mice, with an impressive tumor inhibition rate of 88.0%. Results suggested that CB-NPs can induce necrosis in renal carcinoma cells and tissues, downregulate VEGFA expression, promote renal carcinoma cell apoptosis, and reduce the polarization of M2 macrophages. Discussion: These findings offer innovative perspectives for the treatment of advanced renal carcinoma.

Hyperthermia in Combination with Emerging Targeted and Immunotherapies as a New Approach in Cancer Treatment

Despite significant advancements in the development of novel therapies, cancer continues to stand as a prominent global cause of death. In many cases, the cornerstone of standard-of-care therapy consists of chemotherapy (CT), radiotherapy (RT), or a combination of both. Notably, hyperthermia (HT), which has been in clinical use in the last four decades, has proven to enhance the effectiveness of CT and RT, owing to its recognized potency as a sensitizer. Furthermore, HT exerts effects on all steps of the cancer-immunity cycle and exerts a significant impact on key oncogenic pathways. Most recently, there has been a noticeable expansion of cancer research related to treatment options involving immunotherapy (IT) and targeted therapy (TT), a trend also visible in the research and development pipelines of pharmaceutical companies. However, the potential results arising from the combination of these innovative therapeutic approaches with HT remain largely unexplored. Therefore, this review aims to explore the oncology pipelines of major pharmaceutical companies, with the primary objective of identifying the principal targets of forthcoming therapies that have the potential to be advantageous for patients by specifically targeting molecular pathways involved in HT. The ultimate goal of this review is to pave the way for future research initiatives and clinical trials that harness the synergy between emerging IT and TT medications when used in conjunction with HT.

A light-activatable theranostic combination for ratiometric hypoxia imaging and oxygen-deprived drug activity enhancement

While performing oxygen-related tumour treatments such as chemotherapy and photodynamic therapy, real-time monitoring hypoxia of tumour is of great value and significance. Here, we design a theranostic combination for light-activated ratiometric hypoxia imaging, hypoxia modulating and prodrug activation. This combination consisted of an oxygen-sensitive near-infrared-emitting ratiometric phosphorescence probe and a hypoxia-activated prodrug-loaded covalent organic framework. In this combination, the probe plays two roles, including quantitative monitoring of oxygen concentration by ratiometric imaging and consuming the oxygen of tumour under light excitation by photodynamic therapy. Meanwhile, the enhanced hypoxia microenvironment of tumour can raise the cytotoxicity of prodrug loaded in covalent organic framework, resulting in boosting antitumour therapeutic effects in vivo. This theranostic combination can precisely provide therapeutic regime and screen hypoxia-activated prodrugs based on real-time tumour hypoxia level, offering a strategy to develop hypoxia mediated tumour theranostics with hypoxia targeted prodrugs.

Nanodelivery Systems as a Novel Strategy to Overcome Treatment Failure of Cancer

Despite the tremendous progress in cancer treatment in recent decades, cancers often become resistant due to multiple mechanisms, such as intrinsic or acquired multidrug resistance, which leads to unsatisfactory treatment effects or accompanying metastasis and recurrence, ultimately to treatment failure. With a deeper understanding of the molecular mechanisms of tumors, researchers have realized that treatment designs targeting tumor resistance mechanisms would be a promising strategy to break the therapeutic deadlock. Nanodelivery systems have excellent physicochemical properties, including highly efficient tissue-specific delivery, substantial specific surface area, and controllable surface chemistry, which endow nanodelivery systems with capabilities such as precise targeting, deep penetration, responsive drug release, multidrug codelivery, and multimodal synergy, which are currently widely used in biomedical researches and bring a new dawn for overcoming cancer resistance. Based on the mechanisms of tumor therapeutic resistance, this review summarizes the research progress of nanodelivery systems for overcoming tumor resistance to improve therapeutic efficacy in recent years and offers prospects and challenges of the application of nanodelivery systems for overcoming cancer resistance.

The cell stress and immunity cycle in cancer: Toward next generation of cancer immunotherapy

The cellular stress and immunity cycle is a cornerstone of organismal homeostasis. Stress activates intracellular and intercellular communications within a tissue or organ to initiate adaptive responses aiming to resolve the origin of this stress. If such local measures are unable to ameliorate this stress, then intercellular communications expand toward immune activation with the aim of recruiting immune cells to effectively resolve the situation while executing tissue repair to ameliorate any damage and facilitate homeostasis. This cellular stress-immunity cycle is severely dysregulated in diseased contexts like cancer. On one hand, cancer cells dysregulate the normal cellular stress responses to reorient them toward upholding growth at all costs, even at the expense of organismal integrity and homeostasis. On the other hand, the tumors severely dysregulate or inhibit various components of organismal immunity, for example, by facilitating immunosuppressive tumor landscape, lowering antigenicity, and increasing T-cell dysfunction. In this review we aim to comprehensively discuss the basis behind tumoral dysregulation of cellular stress-immunity cycle. We also offer insights into current understanding of the regulators and deregulators of this cycle and how they can be targeted for conceptualizing successful cancer immunotherapy regimen.

TRAIL-driven targeting and reversing cervical cancer radioresistance by seleno-nanotherapeutics through regulating cell metabolism

Recently, radioresistance has become a major obstacle in the radiotherapy of cervical cancer. To demonstrate enhanced radiosensitization against radioresistant cervical cancer, radioresistant cervical cancer cell line was developed and the mechanism of radioresistance was explored. Due to the overexpression of (death receptor 5, DR5) in cervical cancer, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-overexpressed cervical cancer cell membrane-camouflaged Cu2-xSe nanomedicine (CCMT) was designed. Since the CCMT was encapsulated with TRAIL-modified cell membrane, it represented high target to cervical cancer cell and immune evasion. Furthermore, Cu2-xSe had the ability to scavenge glutathione (GSH) and produce ·OH with excess H2O2 in the tumor microenvironment. The presence of CCMT combined with radiation therapy could effectively increase the 1O2 produced by X-rays. In vitro and in vivo studies elaborated that CCMT exhibited excellent radiosensitization properties to reverse radiotolerance by scavenging GSH and promoting DNA damage, apoptosis, mitochondrial membrane potential damage and metabolic disruption. Collectively, this study suggested that the development of TRAIL-overexpressed cell membrane-camouflaged Cu2-xSe nanomedicine could advance future cervical cancer treatment and minimize the disadvantages associated with radiation treatment.

Engineering Versatile Nanomedicines for Ultrasonic Tumor Immunotherapy

Due to the specific advantages of ultrasound (US) in therapeutic disease treatments, the unique therapeutic US technology has emerged. In addition to featuring a low-invasive targeted cancer-cell killing effect, the therapeutic US technology has been demonstrated to modulate the tumor immune landscape, amplify the therapeutic effect of other antitumor therapies, and induce immunosensitization of tumors to immunotherapy, shedding new light on the cancer treatment. Tremendous advances in nanotechnology are also expected to bring unprecedented benefits to enhancing the antitumor efficiency and immunological effects of therapeutic US, as well as therapeutic US-derived bimodal and multimodal synergistic therapies. This comprehensive review summarizes the immunological effects induced by different therapeutic US technologies, including ultrasound-mediated micro-/nanobubble destruction (UTMD/UTND), sonodynamic therapy (SDT), and focused ultrasound (FUS), as well as the main underlying mechanisms involved. It is also discussed that the recent research progress of engineering intelligent nanoplatform in improving the antitumor efficiency of therapeutic US technologies. Finally, focusing on clinical translation, the key issues and challenges currently faced are summarized, and the prospects for promoting the clinical translation of these emerging nanomaterials and ultrasonic immunotherapy in the future are proposed.

Navigating the Immune Maze: Pioneering Strategies for Unshackling Cancer Immunotherapy Resistance

Cancer immunotherapy has ushered in a transformative era in oncology, offering unprecedented promise and opportunities. Despite its remarkable breakthroughs, the field continues to grapple with the persistent challenge of treatment resistance. This resistance not only undermines the widespread efficacy of these pioneering treatments, but also underscores the pressing need for further research. Our exploration into the intricate realm of cancer immunotherapy resistance reveals various mechanisms at play, from primary and secondary resistance to the significant impact of genetic and epigenetic factors, as well as the crucial role of the tumor microenvironment (TME). Furthermore, we stress the importance of devising innovative strategies to counteract this resistance, such as employing combination therapies, tailoring immune checkpoints, and implementing real-time monitoring. By championing these state-of-the-art methods, we anticipate a paradigm that blends personalized healthcare with improved treatment options and is firmly committed to patient welfare. Through a comprehensive and multifaceted approach, we strive to tackle the challenges of resistance, aspiring to elevate cancer immunotherapy as a beacon of hope for patients around the world.

Alleviating hypoxia to improve cancer immunotherapy

Tumor hypoxia resulting from abnormal and dysfunctional tumor vascular network poses a substantial obstacle to immunotherapy. In fact, hypoxia creates an immunosuppressive tumor microenvironment (TME) through promoting angiogenesis, metabolic reprogramming, extracellular matrix remodeling, epithelial-mesenchymal transition (EMT), p53 inactivation, and immune evasion. Vascular normalization, a strategy aimed at restoring the structure and function of tumor blood vessels, has been shown to improve oxygen delivery and reverse hypoxia-induced signaling pathways, thus alleviates hypoxia and potentiates cancer immunotherapy. In this review, we discuss the mechanisms of tumor tissue hypoxia and its impacts on immune cells and cancer immunotherapy, as well as the approaches to induce tumor vascular normalization. We also summarize the evidence supporting the use of vascular normalization in combination with cancer immunotherapy, and highlight the challenges and future directions of this overlooked important field. By targeting the fundamental problem of tumor hypoxia, vascular normalization proposes a promising strategy to enhance the efficacy of cancer immunotherapy and improve clinical outcomes for cancer patients.

Oncofetal reprogramming in tumor development and progression: novel insights into cancer therapy

Emerging evidence indicates that cancer cells can mimic characteristics of embryonic development, promoting their development and progression. Cancer cells share features with embryonic development, characterized by robust proliferation and differentiation regulated by signaling pathways such as Wnt, Notch, hedgehog, and Hippo signaling. In certain phase, these cells also mimic embryonic diapause and fertilized egg implantation to evade treatments or immune elimination and promote metastasis. Additionally, the upregulation of ATP-binding cassette (ABC) transporters, including multidrug resistance protein 1 (MDR1), multidrug resistance-associated protein 1 (MRP1), and breast cancer-resistant protein (BCRP), in drug-resistant cancer cells, analogous to their role in placental development, may facilitate chemotherapy efflux, further resulting in treatment resistance. In this review, we concentrate on the underlying mechanisms that contribute to tumor development and progression from the perspective of embryonic development, encompassing the dysregulation of developmental signaling pathways, the emergence of dormant cancer cells, immune microenvironment remodeling, and the hyperactivation of ABC transporters. Furthermore, we synthesize and emphasize the connections between cancer hallmarks and embryonic development, offering novel insights for the development of innovative cancer treatment strategies.

Hypoxia is correlated with the tumor immune microenvironment: Potential application of immunotherapy in bladder cancer

OBJECTIVE

Hypoxia, which can considerably affect the tumor microenvironment, hinders the use of immunotherapy in bladder cancer (BLCA). Therefore, we aimed to identify reliable hypoxia-related biomarkers to guide clinical immunotherapy in BLCA.

METHODS

Using data downloaded from TCGA-BLCA cohort, we determined BLCA subtypes which divide 408 samples into different subtypes. Tumor immune infiltration levels of two clusters were quantified using ssGSEA, MCPcounter, EPIC, ESTIMATE, and TIMER algorithms. Next, we constructed a hypoxia score based on the expression of hypoxia-related genes. The IMvigor210 cohort and SubMap analysis were used to predict immunotherapeutic responses in patients with different hypoxia scores. Hub genes were screened using cytoscape, immunohistochemistry (IHC), and multispectral immunofluorescence were used to detect the spatial distribution of immune markers.

RESULTS

Patients with BLCA were categorized into cluster1 (n = 227) and Cluster2 (n = 181). Immune infiltration and expression of immune markers were higher in Cluster1. Immune infiltration was also more obvious in the high-hypoxia score group which related to a better predicted response to immunotherapy. IHC, and multispectral immunofluorescence confirmed the importance of TLR8 in immune infiltration and immune phenotype.

CONCLUSIONS

BLCA subtype can evaluate the infiltration of immune cells in the tumor microenvironment of different patients. Hypoxia score in this study could effectively predict immunotherapeutic responses in patients with BLCA. TLR8 may be a potential target for clinical immunotherapy.

Hypoxic Effects on Matrix Metalloproteinases' Expression in the Tumor Microenvironment and Therapeutic Perspectives

The tumor microenvironment (TME) is characterized by an acidic pH and low oxygen concentrations. Hypoxia induces neoplastic cell evasion of the immune surveillance, rapid DNA repair, metabolic reprogramming, and metastasis, mainly as a response to the hypoxic inducible factors (HIFs). Likewise, cancer cells increase matrix metalloproteinases' (MMPs) expression in response to TME conditions, allowing them to migrate from the primary tumor to different tissues. Since HIFs and MMPs are augmented in the hypoxic TME, it is easy to consider that HIFs participate directly in their expression regulation. However, not all MMPs have a hypoxia response element (HRE)-HIF binding site. Moreover, different transcription factors and signaling pathways activated in hypoxia conditions through HIFs or in a HIF-independent manner participate in MMPs' transcription. The present review focuses on MMPs' expression in normal and hypoxic conditions, considering HIFs and a HIF-independent transcription control. In addition, since the hypoxic TME causes resistance to anticancer conventional therapy, treatment approaches using MMPs as a target alone, or in combination with other therapies, are also discussed.

Multifunctional Tumor-Targeting Carbon Dots for Tumor Microenvironment Activated Ferroptosis and Immunotherapy in Cancer Treatment

As an emerging cancer treatment strategy, ferroptosis is distinguished by the perturbation of lipid metabolism equilibrium and the accumulation of lipid peroxidation. However, the efficacy is consistently hindered by excessive GSH in the tumor microenvironment (TME). Here, this work designed and prepared multifunctional tumor-targeting carbon dots (FG-CDs@Cu) for ferroptosis and immunotherapy. Cu2+ in FG-CDs@Cu rapidly depletes high concentrations of GSH and inhibits glutathione peroxidase 4 (GPX4) expression in an acidic TME. Meanwhile, the generated Cu+ produced reactive oxygen species (ROS) through Fenton-like reaction. Due to the high efficiency of ROS production and GSH depletion, ferroptosis mediated by oxidative stress is significantly enhanced by FG-CDs@Cu in vivo, which can induce immunogenic cell death and promote CD8+ T cell infiltration. Meanwhile, the generated O2 effectively improves the hypoxic environment of the cells and leads to the reduction of hypoxia factor-1α (HIF-1α) expression, which activates the transformation of tumor-promoting M2-type tumor-associated macrophages (TAMs) to tumor-inhibiting M1-type TAMs, further enhancing the immune response and ferroptosis. The in vivo tests suggested that FG-CDs@Cu could efficiently suppress tumor growth in the mouse model and did not cause obvious toxicity. The combination with antiprogrammed death-ligand 1 (αPD-L1) synergy immune therapy could effectively restrain the growth of distal tumors, suggesting the significant potential of FG-CDs@Cu in augmenting ferroptosis and immunotherapy for efficacious cancer treatment.

Radiological artificial intelligence - predicting personalized immunotherapy outcomes in lung cancer

Personalized medicine has revolutionized approaches to treatment in the field of lung cancer by enabling therapies to be specific to each patient. However, physicians encounter an immense number of challenges in providing the optimal treatment regimen for the individual given the sheer complexity of clinical aspects such as tumor molecular profile, tumor microenvironment, expected adverse events, acquired or inherent resistance mechanisms, the development of brain metastases, the limited availability of biomarkers and the choice of combination therapy. The integration of innovative next-generation technologies such as deep learning-a subset of machine learning-and radiomics has the potential to transform the field by supporting clinical decision making in cancer treatment and the delivery of precision therapies while integrating numerous clinical considerations. In this review, we present a brief explanation of the available technologies, the benefits of using these technologies in predicting immunotherapy response in lung cancer, and the expected future challenges in the context of precision medicine.

Transcription factor LHX9 (LIM Homeobox 9) enhances pyruvate kinase PKM2 activity to induce glycolytic metabolic reprogramming in cancer stem cells, promoting gastric cancer progression

BACKGROUND

Glycolytic metabolic reprogramming is a phenomenon in which cells undergo altered metabolic patterns during malignant transformation, mainly involving various aspects of glycolysis, electron transport chain, oxidative phosphorylation, and pentose phosphate pathway. This reprogramming phenomenon can be used as one of the markers of tumorigenesis and development. Pyruvate kinase is the third rate-limiting enzyme in the sugar metabolism process by specifically catalyzing the irreversible conversion of PEP to pyruvate.

PURPOSE

This study aimed to reveal the critical mediator(s) that regulate glycolytic metabolism reprogramming in gastric cancer and their underlying molecular mechanism and then explore the molecular mechanisms by which LHX9 may be involved in regulating gastric cancer (GC) progression.

METHODS

Firstly, we downloaded the GC and glycolysis-related microarray datasets from TCGA and MSigDB databases and took the intersection to screen out the transcription factor LHX9 that regulates GC glycolytic metabolic reprogramming. Software packages were used for differential analysis, single gene predictive analysis, and Venn diagram. In addition, an enrichment analysis of the glycolytic pathway was performed. Immunohistochemical staining was performed for LHX9 and PKM2 protein expression in 90 GC patients, and the association between their expressions was evaluated by Spearman's correlation coefficient method. Three human GC cell lines (AGS, NCI-N87, HGC-27) were selected for in vitro experimental validation. Flow cytometry was utilized to determine the stem cell marker CD44 expression status in GCSCs. A sphere formation assay was performed to evaluate the sphere-forming capabilities of GCSCs. In addition, RT-qPCR and Western blot experiments were employed to investigate the tumor stem cell markers OCT4 and SOX2 expression levels in GCSCs. Furthermore, a lentiviral expression vector was constructed to assess the impact of downregulating LHX9 or PKM2 on the glycolytic metabolic reprogramming of GCSCs. The proliferation, migration, and invasion of GCSCs were then detected by CCK-8, EdU, and Transwell assays. Subsequently, the mutual binding of LHX9 and PKM2 was verified using chromatin immunoprecipitation and dual luciferase reporter genes. In vivo experiments were verified by establishing a subcutaneous transplantation tumor model in nude mice, observing the size and volume of tumors in vivo in nude mice, and obtaining fresh tissues for subsequent experiments.

RESULTS

Bioinformatics analysis revealed that LHX9 might be involved in the occurrence and development of GC through regulating glycolytic metabolism. High LHX9 expression could be used as a reference marker for prognosis prediction of GC patients. Clinical tissue assays revealed that LHX9 and PKM2 were highly expressed in GC tissues. Meanwhile, GC tissues also highly expressed glycolysis-associated protein GLUT1 and tumor cell stemness marker CD44. In vitro cellular assays showed that LHX9 could enhance its activity and induce glycolytic metabolic reprogramming in GCSCs through direct binding to PKM2. In addition, the knockdown of LHX9 inhibited PKM2 activity and glycolytic metabolic reprogramming and suppressed the proliferation, migration, and invasive ability of GCSCs. In vivo animal experiments further confirmed that the knockdown of LHX9 could reduce the tumorigenic ability of GCSCs in nude mice by inhibiting PKM2 activity and glycolytic metabolic reprogramming.

CONCLUSION

The findings suggest that both LHX9 and PKM2 are highly expressed in GCs, and LHX9 may induce the reprogramming of glycolytic metabolism through transcriptional activation of PKM2, enhancing the malignant biological properties of GCSCs and ultimately promoting GC progression.

Dose-Specific Intratumoral GM-CSF Modulates Breast Tumor Oxygenation and Antitumor Immunity

GM-CSF has been employed as an adjuvant to cancer immunotherapy with mixed results based on dosage. We previously showed that GM-CSF regulated tumor angiogenesis by stimulating soluble vascular endothelial growth factor (VEGF) receptor-1 from monocytes/macrophages in a dose-dependent manner that neutralized free VEGF, and intratumoral injections of high-dose GM-CSF ablated blood vessels and worsened hypoxia in orthotopic polyoma middle T Ag (PyMT) triple-negative breast cancer (TNBC). In this study, we assessed both immunoregulatory and oxygen-regulatory components of low-dose versus high-dose GM-CSF to compare effects on tumor oxygen, vasculature, and antitumor immunity. We performed intratumoral injections of low-dose GM-CSF or saline controls for 3 wk in FVB/N PyMT TNBC. Low-dose GM-CSF uniquely reduced tumor hypoxia and normalized tumor vasculature by increasing NG2+ pericyte coverage on CD31+ endothelial cells. Priming of "cold," anti-PD1-resistant PyMT tumors with low-dose GM-CSF (hypoxia reduced) sensitized tumors to anti-PD1, whereas high-dose GM-CSF (hypoxia exacerbated) did not. Low-dose GM-CSF reduced hypoxic and inflammatory tumor-associated macrophage (TAM) transcriptional profiles; however, no phenotypic modulation of TAMs or tumor-infiltrating lymphocytes were observed by flow cytometry. In contrast, high-dose GM-CSF priming increased infiltration of TAMs lacking the MHC class IIhi phenotype or immunostimulatory marker expression, indicating an immunosuppressive phenotype under hypoxia. However, in anti-PD1 (programmed cell death 1)-susceptible BALB/c 4T1 tumors (considered hot versus PyMT), high-dose GM-CSF increased MHC class IIhi TAMs and immunostimulatory molecules, suggesting disparate effects of high-dose GM-CSF across PyMT versus 4T1 TNBC models. Our data demonstrate a (to our knowledge) novel role for low-dose GM-CSF in reducing tumor hypoxia for synergy with anti-PD1 and highlight why dosage and setting of GM-CSF in cancer immunotherapy regimens require careful consideration.

Nanomedicine Strategies in Conquering and Utilizing the Cancer Hypoxia Environment

Cancer with a complex pathological process is a major disease to human welfare. Due to the imbalance between oxygen (O2) supply and consumption, hypoxia is a natural characteristic of most solid tumors and an important obstacle for cancer therapy, which is closely related to tumor proliferation, metastasis, and invasion. Various strategies to exploit the feature of tumor hypoxia have been developed in the past decade, which can be used to alleviate tumor hypoxia, or utilize the hypoxia for targeted delivery and diagnostic imaging. The strategies to alleviate tumor hypoxia include delivering O2, in situ O2 generation, reprogramming the tumor vascular system, decreasing O2 consumption, and inhibiting HIF-1 related pathways. On the other side, hypoxia can also be utilized for hypoxia-responsive chemical construction and hypoxia-active prodrug-based strategies. Taking advantage of hypoxia in the tumor region, a number of methods have been applied to identify and keep track of changes in tumor hypoxia. Herein, we thoroughly review the recent progress of nanomedicine strategies in both conquering and utilizing hypoxia to combat cancer and put forward the prospect of emerging nanomaterials for future clinical transformation, which hopes to provide perspectives in nanomaterials design.

T-cell dysfunction by pseudohypoxia and autocrine purinergic signaling in chronic lymphocytic leukemia

Acquired T-cell dysfunction is common in chronic B-cell malignancies. Given the strong connection between T-cell metabolism and function, we investigated metabolic alterations as the basis of T-cell dysfunction induced by malignant cells. Using B-cell malignant cell lines and human peripheral blood mononuclear cells, we first established a model that recapitulates major aspects of cancer-induced T-cell dysfunction. Cell lines derived from chronic lymphocytic leukemia (CLL) (PGA-1, CII, and Mec-1), but not from other B-cell malignancies, altered the T-cell metabolome by generating a pseudohypoxic state. T cells were retained in aerobic glycolysis and were not able to switch to oxidative phosphorylation (OXPHOS). Moreover, T cells produced immunosuppressive adenosine that negatively affected function by dampening the activation, which could be restored by the blocking of adenosine receptors. Subsequently, we uncovered a similar hypoxic-like signature in autologous T cells from primary CLL samples. Pseudohypoxia was reversible upon depletion of CLL cells ex vivo and, importantly, after the in vivo reduction of the leukemic burden with combination therapy (venetoclax and obinutuzumab), restoring T-cell function. In conclusion, we uncovered a pseudohypoxic program connected with T-cell dysfunction in CLL. Modulation of hypoxia and the purinergic pathway might contribute to therapeutic restoration of T-cell function.

Resistance to immune checkpoint inhibitors in gastric cancer

Gastric cancer (GC) is one of the most common gastrointestinal malignancies worldwide. In the past decade, with the development of early diagnostic techniques, a clear decline in GC incidence has been observed, but its mortality remains high. The emergence of new immunotherapies such as immune checkpoint inhibitors (ICIs) has changed the treatment of GC patients to some extent. However, only a small number of patients with advanced GC have a durable response to ICI treatment, and the efficacy of ICIs is very limited. Existing studies have shown that the failure of immunotherapy is mainly related to the development of ICI resistance in patients, but the understanding of the resistance mechanism is still insufficient. Therefore, clarifying the mechanism of GC immune resistance is critical to improve its treatment and clinical benefit. In this review, we focus on summarizing the mechanisms of primary or acquired resistance to ICI immunotherapy in GC from both internal and external aspects of the tumor. At the same time, we also briefly discuss some other possible resistance mechanisms in light of current studies.

Development and validation of a combined hypoxia- and metabolism-related prognostic signature to predict clinical prognosis and immunotherapy responses in clear cell renal cell carcinoma

Background

Hypoxia and metabolism are closely correlated with the progression of cancer. We aimed to construct a combined hypoxia- and metabolism-related genes (HMRGs) prognostic signature to predict survival and immunotherapy responses in patients with clear cell renal cell carcinoma (ccRCC).

Methods

The RNA-seq profiles and clinical data of ccRCC were acquired from the TCGA and the ArrayExpress (E-MTAB-1980) databases. Least absolute shrinkage and selection operator (LASSO) and univariate and multivariate Cox regression analyses were applied to establish a prognostic signature. The E-MTAB-1980 cohort was selected for validation. The effectiveness and reliability of the signature were further evaluated by Kaplan-Meier (K-M) survival and time-dependent receiver operating characteristic (ROC) curves. Further analyses, including functional enrichment, ssGSEA algorithm, CIBERSORT algorithm, and expression of immune checkpoints, were explored to investigate immune status and immunotherapy responses.

Results

We constructed a prognostic eight-gene signature with IRF6, TEK, PLCB2, ABCB1, TGFA, COL4A5, PLOD2, and TUBB6. Patients were divided into high-risk and low-risk groups based on the medium-risk score. The K-M analysis revealed that patients in the high-risk group had an apparently poor prognosis compared to those in the low-risk group in the TCGA (p < 0.001) and E-MTAB-1980 (p < 0.005). The area under ROC curve (AUC) of the prognostic signature was 0.8 at 1 year, 0.77 at 3 years, and 0.78 at 5 years in the TCGA, respectively, and was 0.82 at 1 year, 0.74 at 3 years, and 0.75 at 5 years in the E-MTAB-1980, respectively. Independent prognostic analysis confirmed the risk score as a separate prognostic factor in ccRCC patients (p < 0.001). The results of ssGSEA showed not only a high degree of immune cell infiltration but also high scores of immune-related functions in the high-risk group. The CIBERSORT analysis further confirmed that the abundance of immune cells was apparently different between the two risk groups. The risk score was significantly correlated with the expression of cytotoxic T lymphocyte-associated antigen-4 (CTLA4), lymphocyte-activation gene 3 (LAG3), and programmed cell death protein 1 (PD-1).

Conclusion

The HMRGs signature could be used to predict clinical prognosis, evaluate the efficacy of immunotherapy, and guide personalized immunotherapy in ccRCC patients.

Comprehensive analysis of resistance mechanisms to EGFR-TKIs and establishment and validation of prognostic model

PURPOSE

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are the first-line therapy for patients with lung adenocarcinoma (LUAD) harboring activating EGFR mutations. However, the emergence of drug resistance to EGFR-TKIs remains a critical obstacle for successful treatment and is associated with poor patient outcomes. The overarching objective of this study is to apply bioinformatics tools to gain insights into the mechanisms underlying resistance to EGFR-TKIs and develop a robust predictive model.

METHODS

The genes associated with gefitinib resistance in the LUAD cell Gene Expression Omnibus (GEO) database were identified using gene chip expression data. Functional enrichment analysis, gene set enrichment analysis (GSEA), and immune infiltration analysis were performed to comprehensively explore the mechanism of gefitinib resistance. Furthermore, a GRRG_score was constructed by integrating genes related to LUAD prognosis from The Cancer Genome Atlas (TCGA) database with the screened Gefitinib Resistant Related differentially expressed genes (GRRDEGs) using the Least Absolute Shrinkage and Selection Operator (LASSO) and Cox regression analyses. Furthermore, we conducted an in-depth analysis of the tumor microenvironment (TME) features and their association with immune infiltration between different GRRG_score groups. A prognostic model for LUAD was developed based on the GRRG_score and validated. The HPA database was used to validate protein expression. The CTR-DB database was utilized to validate the results of drug therapy prediction based on the relevant genes.

RESULTS

A total of 110 differentially expression genes were identified. Pathway enrichment analysis of DEGs showed that the differentially expressed genes were mainly enriched in Mucin type O-glycan biosynthesis, Cytokine-cytokine receptor interaction, Sphingolipid metabolism. Gene set enrichment analysis showed that biological processes strongly correlated with gefitinib resistance were cell proliferation and immune-related pathways, EPITHELIAL_MESENCHYMAL_TRANSITION, APICAL_SURFACE, and APICAL_JUNCTION were highly expressed in the drug-resistant group; KRAS_SIGNALING_DN, HYPOXIA, and HEDGEHOG_SIGNALING were highly expressed in the drug-resistant group. The GRRG_score was constructed based on the expression levels of 13 genes, including HSPA2, ATP8B3, SPOCK1, EIF6, NUP62CL, BCAR3, PCSK9, NT5E, FLNC, KRT8, FSCN1, ANGPTL4, and ID1. We further screened and validated two key genes, namely, NUP62CL and KRT8, which exhibited predictive value for both prognosis and drug resistance.

CONCLUSIONS

Our study identified several novel GRRDEGs and provided insight into the underlying mechanisms of gefitinib resistance in LUAD. Our results have implications for developing more effective treatment strategies and prognostic models for LUAD patients.

Tumor associated macrophages in esophageal squamous carcinoma: Promising therapeutic implications

Esophageal squamous carcinoma (ESCC) is a prevalent and highly lethal malignant tumor, with a five-year survival rate of approximately 20 %. Tumor-associated macrophages (TAMs) are the most prominent immune cells in the tumor microenvironment (TME), comprising over 50 % of the tumor volume. TAMs can be polarized into two distinct phenotypes, M1-type and M2-type, through interactions with cancer cells. M2-type TAMs are more abundant than M1-type TAMs in the TME, contributing to tumor progression, such as tumor cell survival and the construction of an immunosuppressive environment. This review focuses on the role of TAMs in ESCC, including their polarization, impact on tumor proliferation, angiogenesis, invasion, migration, therapy resistance, and immunosuppression. In addition, we discuss the potential of targeting TAMs for clinical therapy in ESCC. A thorough comprehension of the molecular biology about TAMs is essential for the development of innovative therapeutic strategies to treat ESCC.

Hypoxia-inducing cryogels uncover key cancer-immune cell interactions in an oxygen-deficient tumor microenvironment

Hypoxia is a major factor shaping the immune landscape, and several cancer models have been developed to emulate hypoxic tumors. However, to date, they still have several limitations, such as the lack of reproducibility, inadequate biophysical cues, limited immune cell infiltration, and poor oxygen (O2) control, leading to non-pathophysiological tumor responses. Therefore, it is essential to develop better cancer models that mimic key features of the tumor extracellular matrix and recreate tumor-associated hypoxia while allowing cell infiltration and cancer-immune cell interactions. Herein, hypoxia-inducing cryogels (HICs) have been engineered using hyaluronic acid (HA) to fabricate three-dimensional microtissues and model a hypoxic tumor microenvironment. Specifically, tumor cell-laden HICs have been designed to deplete O2 locally and induce long-standing hypoxia. HICs promoted changes in hypoxia-responsive gene expression and phenotype, a metabolic adaptation to anaerobic glycolysis, and chemotherapy resistance. Additionally, HIC-supported tumor models induced dendritic cell (DC) inhibition, revealing a phenotypic change in the plasmacytoid DC (pDC) subset and an impaired conventional DC (cDC) response in hypoxia. Lastly, our HIC-based melanoma model induced CD8+ T cell inhibition, a condition associated with the downregulation of pro-inflammatory cytokine secretion, increased expression of immunomodulatory factors, and decreased degranulation and cytotoxic capacity of T cells. Overall, these data suggest that HICs can be used as a tool to model solid-like tumor microenvironments and has great potential to deepen our understanding of cancer-immune cell relationship in low O2 conditions and may pave the way for developing more effective therapies.

Hypoxia-induced TMTC3 expression in esophageal squamous cell carcinoma potentiates tumor angiogenesis through Rho GTPase/STAT3/VEGFA pathway

BACKGROUND

Hypoxia is one of most typical features in the tumor microenvironment of solid tumor and an inducer of endoplasmic reticulum (ER) stress, and HIF-1α functions as a key transcription factor regulator to promote tumor angiogenesis in the adaptive response to hypoxia. Increasing evidence has suggested that hypoxia plays an important regulatory role of ER homeostasis. We previously identified TMTC3 as an ER stress mediator under nutrient-deficiency condition in esophageal squamous cell carcinoma (ESCC), but the molecular mechanism in hypoxia is still unclear.

METHODS

RNA sequencing data of TMTC3 knockdown cells and TCGA database were analyzed to determine the association of TMTC3 and hypoxia. Moreover, ChIP assay and dual-luciferase reporter assay were performed to detect the interaction of HIF-1α and TMTC3 promoter. In vitro and in vivo assays were used to investigate the function of TMTC3 in tumor angiogenesis. The molecular mechanism was determined using co-immunoprecipitation assays, immunofluorescence assays and western blot. The TMTC3 inhibitor was identified by high-throughput screening of FDA-approved drugs. The combination of TMTC3 inhibitor and cisplatin was conducted to confirm the efficiency in vitro and in vivo.

RESULTS

The expression of TMTC3 was remarkably increased under hypoxia and regulated by HIF-1α. Knockdown of TMTC3 inhibited the capability of tumor angiogenesis and ROS production in ESCC. Mechanistically, TMTC3 promoted the production of GTP through interacting with IMPDH2 Bateman domain. The activity of Rho GTPase/STAT3, regulated by cellular GTP levels, decreased in TMTC3 knockdown cells, whereas reversed by IMPDH2 overexpression. Additionally, TMTC3 regulated the expression of VEGFA through Rho GTPase/STAT3 pathway. Allopurinol inhibited the expression of TMTC3 and further reduced the phosphorylation and activation of STAT3 signaling pathway in a dose-dependent manner in ESCC. Additionally, the combination of allopurinol and cisplatin significantly inhibited the cell viability in vitro and tumor growth in vivo, comparing with single drug treatment, respectively.

CONCLUSIONS

Collectively, our study clarified the molecular mechanism of TMTC3 in regulating tumor angiogenesis and highlighted the potential therapeutic combination of TMTC3 inhibitor and cisplatin, which proposed a promising strategy for the treatment of ESCC.

HIF-1α drives resistance to ferroptosis in solid tumors by promoting lactate production and activating SLC1A1

Solid tumors have developed robust ferroptosis resistance. The mechanism underlying ferroptosis resistance regulation in solid tumors, however, remains elusive. Here, we report that the hypoxic tumor microenvironment potently promotes ferroptosis resistance in solid tumors in a hypoxia-inducible factor 1α (HIF-1α)-dependent manner. In combination with HIF-2α, which promotes tumor ferroptosis under hypoxia, HIF-1α is the main driver of hypoxia-induced ferroptosis resistance. Mechanistically, HIF-1α-induced lactate contributes to ferroptosis resistance in a pH-dependent manner that is parallel to the classical SLC7A11 and FSP1 systems. In addition, HIF-1α also enhances transcription of SLC1A1, an important glutamate transporter, and promotes cystine uptake to promote ferroptosis resistance. In support of the role of hypoxia in ferroptosis resistance, silencing HIF-1α sensitizes mouse solid tumors to ferroptosis inducers. In conclusion, our results reveal a mechanism by which hypoxia drives ferroptosis resistance and identify the combination of hypoxia alleviation and ferroptosis induction as a promising therapeutic strategy for solid tumors.

Immune checkpoint therapy for solid tumours: clinical dilemmas and future trends

Immune-checkpoint inhibitors (ICBs), in addition to targeting CTLA-4, PD-1, and PD-L1, novel targeting LAG-3 drugs have also been approved in clinical application. With the widespread use of the drug, we must deeply analyze the dilemma of the agents and seek a breakthrough in the treatment prospect. Over the past decades, these agents have demonstrated dramatic efficacy, especially in patients with melanoma and non-small cell lung cancer (NSCLC). Nonetheless, in the field of a broad concept of solid tumours, non-specific indications, inseparable immune response and side effects, unconfirmed progressive disease, and complex regulatory networks of immune resistance are four barriers that limit its widespread application. Fortunately, the successful clinical trials of novel ICB agents and combination therapies, the advent of the era of oncolytic virus gene editing, and the breakthrough of the technical barriers of mRNA vaccines and nano-delivery systems have made remarkable breakthroughs currently. In this review, we enumerate the mechanisms of each immune checkpoint targets, associations between ICB with tumour mutation burden, key immune regulatory or resistance signalling pathways, the specific clinical evidence of the efficacy of classical targets and new targets among different tumour types and put forward dialectical thoughts on drug safety. Finally, we discuss the importance of accurate triage of ICB based on recent advances in predictive biomarkers and diagnostic testing techniques.

Nanomedicine Strategies for Targeting Tumor Stroma

The tumor stroma, or the microenvironment surrounding solid tumors, can significantly impact the effectiveness of cancer therapies. The tumor microenvironment is characterized by high interstitial pressure, a consequence of leaky vasculature, and dense stroma created by excessive deposition of various macromolecules such as collagen, fibronectin, and hyaluronic acid (HA). In addition, non-cancerous cells such as cancer-associated fibroblasts (CAFs) and the extracellular matrix (ECM) itself can promote tumor growth. In recent years, there has been increased interest in combining standard cancer treatments with stromal-targeting strategies or stromal modulators to improve therapeutic outcomes. Furthermore, the use of nanomedicine, which can improve the delivery and retention of drugs in the tumor, has been proposed to target the stroma. This review focuses on how different stromal components contribute to tumor progression and impede chemotherapeutic delivery. Additionally, this review highlights recent advancements in nanomedicine-based stromal modulation and discusses potential future directions for developing more effective stroma-targeted cancer therapies.

Optimizing Boron Neutron Capture Therapy (BNCT) to Treat Cancer: An Updated Review on the Latest Developments on Boron Compounds and Strategies

Boron neutron capture therapy (BNCT) is a tumor-selective particle radiotherapy. It combines preferential boron accumulation in tumors and neutron irradiation. The recent initiation of BNCT clinical trials employing hospital-based accelerators rather than nuclear reactors as the neutron source will conceivably pave the way for new and more numerous clinical trials, leading up to much-needed randomized trials. In this context, it would be interesting to consider the implementation of new boron compounds and strategies that will significantly optimize BNCT. With this aim in mind, we analyzed, in this review, those articles published between 2020 and 2023 reporting new boron compounds and strategies that were proved therapeutically useful in in vitro and/or in vivo radiobiological studies, a critical step for translation to a clinical setting. We also explored new pathologies that could potentially be treated with BNCT and newly developed theranostic boron agents. All these radiobiological advances intend to solve those limitations and questions that arise during patient treatment in the clinical field, with BNCT and other therapies. In this sense, active communication between clinicians, radiobiologists, and all disciplines will improve BNCT for cancer patients, in a cost- and time-effective way.