CDK12/13 inhibition induces immunogenic cell death and enhances anti-PD-1 anticancer activity in breast cancer

Identification of immunogenic cell death-related damage-related molecular patterns (DAMPs) to predict outcomes in patients with head and neck squamous cell carcinoma

PURPOSE

Head and neck cancer is the sixth most common type of cancer worldwide, wherein the immune responses are closely associated with disease occurrence, development, and prognosis. Investigation of the role of immunogenic cell death-related genes (ICDGs) in adaptive immune response activation may provide cues into the mechanism underlying the outcome of HNSCC immunotherapy.

METHODS

ICDGs expression patterns in HNSCC were analyzed, after which consensus clustering in HNSCC cohort conducted. A 4-gene prognostic model was constructed through LASSO and Cox regression analyses to analyze the prognostic index using the TCGA dataset, followed by validation with two GEO datasets. The distribution of immune cells and the response to immunotherapy were compared between different risk subtypes through multiple algorithms. Moreover, immunohistochemical (IHC) analyses were conducted to validate the prognostic value of HSP90AA1 as a predictor of HNSCC patient prognosis. In vitro assays were performed to further detect the effect of HSP90AA1 in the development of HNSCC.

RESULTS

A novel prognostic index based on four ICDGs was constructed and proved to be useful as an independent factor of HNSCC prognosis. The risk score derived from this model grouped patients into high- and low-risk subtypes, wherein the high-risk subtype had worse survival outcomes and poorer immunotherapy response. IHC analysis validated the applicability of HSP90AA1 as a predictor of prognosis of HNSCC patients. HSP90AA1 expression in tumor cells promotes the progression of HNSCC.

CONCLUSIONS

Together, these results highlight a novel four-gene prognostic signature as a valuable tool to assess survival status and prognosis of HNSCC patients.

Clinical application of immunogenic cell death inducers in cancer immunotherapy: turning cold tumors hot

Immunotherapy has emerged as a promising cancer treatment option in recent years. In immune "hot" tumors, characterized by abundant immune cell infiltration, immunotherapy can improve patients' prognosis by activating the function of immune cells. By contrast, immune "cold" tumors are often less sensitive to immunotherapy owing to low immunogenicity of tumor cells, an immune inhibitory tumor microenvironment, and a series of immune-escape mechanisms. Immunogenic cell death (ICD) is a promising cellular process to facilitate the transformation of immune "cold" tumors to immune "hot" tumors by eliciting innate and adaptive immune responses through the release of (or exposure to) damage-related molecular patterns. Accumulating evidence suggests that various traditional therapies can induce ICD, including chemotherapy, targeted therapy, radiotherapy, and photodynamic therapy. In this review, we summarize the biological mechanisms and hallmarks of ICD and introduce some newly discovered and technologically innovative inducers that activate the immune system at the molecular level. Furthermore, we also discuss the clinical applications of combing ICD inducers with cancer immunotherapy. This review will provide valuable insights into the future development of ICD-related combination therapeutics and potential management for "cold" tumors.

Loss of heterozygosity impacts MHC expression on the immune microenvironment in CDK12-mutated prostate cancer

BACKGROUND

In prostate cancer (PCa), well-established biomarkers such as MSI status, TMB high, and PDL1 expression serve as reliable indicators for favorable responses to immunotherapy. Recent studies have suggested a potential association between CDK12 mutations and immunotherapy response; however, the precise mechanisms through which CDK12 mutation may influence immune response remain unclear. A plausible explanation for immune evasion in this subset of CDK12-mutated PCa may be reduced MHC expression.

RESULTS

Using genomic data of CDK12-mutated PCa from 48 primary and 10 metastatic public domain samples and a retrospective cohort of 53 low-intermediate risk primary PCa, we investigated how variation in the expression of the MHC genes affected associated downstream pathways. We classified the patients based on gene expression quartiles of MHC-related genes and categorized the tumors into "High" and "Low" expression levels. CDK12-mutated tumors with higher MHC-expressed pathways were associated with the immune system and elevated PD-L1, IDO1, and TIM3 expression. Consistent with an inflamed tumor microenvironment (TME) phenotype, digital cytometric analyses identified increased CD8 + T cells, B cells, γδ T cells, and M1 Macrophages in this group. In contrast, CDK12-mutated tumors with lower MHC expression exhibited features consistent with an immune cold TME phenotype and immunoediting. Significantly, low MHC expression was also associated with chromosome 6 loss of heterozygosity (LOH) affecting the entire HLA gene cluster. These LOH events were observed in both major clonal and minor subclonal populations of tumor cells. In our retrospective study of 53 primary PCa cases from this Institute, we found a 4% (2/53) prevalence of CDK12 mutations, with the confirmation of this defect in one tumor through Sanger sequencing. In keeping with our analysis of public domain data this tumor exhibited low MHC expression at the RNA level. More extensive studies will be required to determine whether reduced HLA expression is generally associated with primary tumors or is a specific feature of CDK12 mutated PCa.

CONCLUSIONS

These data show that analysis of CDK12 alteration, in the context of MHC expression levels, and LOH status may offer improved predictive value for outcomes in this potentially actionable genomic subgroup of PCa. In addition, these findings highlight the need to explore novel therapeutic strategies to enhance MHC expression in CDK12-defective PCa to improve immunotherapy responses.

Calreticulin, a potential coregulator of immune checkpoints and biomarker associated with tumor microenvironment and clinical prognostic significance in breast invasive carcinoma

As a promising immune checkpoint of immunogenic cell death (ICD) and multifunctional calcium-binding molecular chaperone, calreticulin (CALR) has been attracting increasing attention. CALR mainly locates in cellular endoplasmic reticulum and significantly affects cell proliferation, invasion, induction of apoptosis, and angiogenesis in breast invasive carcinoma (BRCA). CALR overexpression might be correlated with a worse outcome. Nonetheless, it remains obscure how CALR correlates with immune infiltration and survival prognosis of BRCA. In this study, we investigated CALR expression utilizing RNAseq data from the cancer genome atlas (TCGA) and genotype-tissue expression (GTEx) database. The prognostic value of CALR was analyzed using clinical survival data. Enrichment analysis was conducted using the R package "clusterProfiler." We downloaded the immune cell infiltration score of TCGA samples from published articles and online databases and performed a correlation analysis between immune cell infiltration levels and CALR expression. We further assessed the association between CALR and immunomodulators. Moreover, we also evaluated the expression of CALR in 100 formalin-fixed and paraffin-embedded breast cancer and adjacent normal breast tissue specimens. Our results found that CALR was highly expressed in BRCA, and CALR expression levels differed in pathological stages, T stages, and N stages. Besides, these results suggested that CALR overexpression may have adverse effects on the progression-free interval (PFI) and disease-free interval (DFI), which may be related to tumor proliferation, invasion, and metastasis, leading to tumor deterioration. Meanwhile, immune cell infiltration analysis revealed a correlation between the expression of CALR and the number of neutrophils and dendritic cells, suggesting that CALR was highly correlated with many immunomodulators in BRCA. Our results provide potential biomarkers of CALR in BRCA. CALR may interact synergistically with other immunomodulators to regulate the immune microenvironment, which could be utilized to develop new immunotherapy drugs.

Immunogenic cell stress and death in the treatment of cancer

The successful treatment of oncological malignancies which results in long-term disease control or the complete eradication of cancerous cells necessitates the onset of adaptive immune responses targeting tumor-specific antigens. Such desirable anticancer immunity can be triggered via the induction of immunogenic cell death (ICD) of cancer cells, thus converting malignant cells into an in situ vaccine that elicits T cell mediated adaptive immune responses and establishes durable immunological memory. The exploration of ICD for cancer treatment has been subject to extensive research. However, functional heterogeneity among ICD activating therapies in many cases requires specific co-medications to achieve full-blown efficacy. Here, we described the hallmarks of ICD and classify ICD activators into three distinct functional categories namely, according to their mode of action: (i) ICD inducers, which increase the immunogenicity of malignant cells, (ii) ICD sensitizers, which prime cellular circuitries for ICD induction by conventional cytotoxic agents, and (iii) ICD enhancers, which improve the perception of ICD signals by antigen presenting dendritic cells. Altogether, ICD induction, sensitization and enhancement offer the possibility to convert well-established conventional anticancer therapies into immunotherapeutic approaches that activate T cell-mediated anticancer immunity.

CDK12 inhibition upregulates ATG7 triggering autophagy via AKT/FOXO3 pathway and enhances anti-PD-1 efficacy in colorectal cancer

As the world's fourth most deadly cancer, colorectal cancer (CRC) still needed the novel therapeutic drugs and target urgently. Although cyclin-dependent kinase 12 (CDK12) has been shown to be implicated in the malignancy of several types of cancer, its functional role and mechanism in CRC remain largely unknown. Here, we found that suppression of CDK12 inhibited tumor growth in CRC by inducing apoptosis. And CDK12 inhibition triggered autophagy by upregulating autophagy related gene 7 (ATG7) expression. Inhibition of autophagy by ATG7 knockdown and chloroquine (CQ) further decreased cell viability induced by CDK12 inhibition. Further mechanism exploration showed that CDK12 interacted with protein kinase B (AKT) regulated autophagy via AKT/forkhead box O3 (AKT/FOXO3) pathway. FOXO3 transcriptionally upregulated ATG7 expression and autophagy when CDK12 inhibition in CRC. Level of CDK12 and p-FOXO3/FOXO3 ratio were correlated with survival in CRC patients. Moreover, CDK12 inhibition improved the efficacy of anti-programmed cell death 1(PD-1) therapy in CRC murine models by enhancing CD8 + T cells infiltration. Thus, our study founded that CDK12 inhibition upregulates ATG7 triggering autophagy via AKT/FOXO3 pathway and enhances anti-PD-1 efficacy in CRC. We revealed the roles of CDK12/FOXO3/ATG7 in regulating CRC progression, suggesting potential biomarkers and therapeutic target for CRC.

HMGB1 in the interplay between autophagy and apoptosis in cancer

Lysosome-mediated autophagy and caspase-dependent apoptosis are dynamic processes that maintain cellular homeostasis, ensuring cell health and functionality. The intricate interplay and reciprocal regulation between autophagy and apoptosis are implicated in various human diseases, including cancer. High-mobility group box 1 (HMGB1), a nonhistone chromosomal protein, plays a pivotal role in coordinating autophagy and apoptosis levels during tumor initiation, progression, and therapy. The regulation of autophagy machinery and the apoptosis pathway by HMGB1 is influenced by various factors, including the protein's subcellular localization, oxidative state, and interactions with binding partners. In this narrative review, we provide a comprehensive overview of the structure and function of HMGB1, with a specific focus on the interplay between autophagic degradation and apoptotic death in tumorigenesis and cancer therapy. Gaining a comprehensive understanding of the significance of HMGB1 as a biomarker and its potential as a therapeutic target in tumor diseases is crucial for advancing our knowledge of cell survival and cell death.

Trans-Regulation of Alternative PD-L1 mRNA Processing by CDK12 in Non-Small-Cell Lung Cancer Cells

Immunotherapy using checkpoint inhibitors targeting the interaction between PD-1 on T cells and PD-L1 on cancer cells has shown significant results in non-small-cell lung cancer (NSCLC). Not all patients respond to the therapy, and PD-L1 expression heterogeneity is proposed to be one determinant for this. The alternative processing of PD-L1 RNA, which depends on an alternative poly-A site in intron 4, generates a shorter mRNA variant (PD-L1v4) encoding soluble PD-L1 (sPD-L1), relative to the canonical PD-L1v1 mRNA encoding membrane-associated PD-L1 (mPD-L1). This study aimed to identify factors influencing the ratio between these two PD-L1 mRNAs in NSCLC cells. First, we verified the existence of the alternative PD-L1 RNA processing in NSCLC cells, and from in silico analyses, we identified a candidate list of regulatory factors. Examining selected candidates showed that CRISPR/Cas9-generated loss-of-function mutations in CDK12 increased the PD-L1v4/PD-L1v1 mRNA ratio and, accordingly, the sPD-L1/mPD-L1 balance. The CDK12/13 inhibitor THZ531 could also increase the PD-L1v4/PD-L1v1 mRNA ratio and impact the PD-L1 transcriptional response to IFN-γ stimulation. The fact that CDK12 regulates PD-L1 transcript variant formation in NSCLC cells is consistent with CDK12's role in promoting transcriptional elongation over intron-located poly-A sites. This study lays the groundwork for clinical investigations to delineate the implications of the CDK12-mediated balancing of sPD-L1 relative to mPD-L1 for immunotherapeutic responses in NSCLC.

An immunogenic cell death-related signature predicts prognosis and immunotherapy response in stomach adenocarcinoma

The immunogenic cell death (ICD) is a specific type of regulatory cell death (RCD), which induces adaptive immunity against antigens of dead cells. ICDs have received increasing attention for their potential role in tumor microenvironment reprogramming and immunotherapy. However, the relationship between ICD-related features and stomach adenocarcinoma (STAD) prognosis, immune cell infiltration and immunotherapy remains unclear. Patients were divided into different ICD-related subtypes by consensus clustering. The differences in prognosis, Tumor microenvironment (TME), and immune checkpoint expression between different ICD-related subtypes were systematically assessed. Additionally, we constructed an ICD-related gene risk score (ICDRS). We systematically analyzed the correlation between ICDRS and prognosis, TME, immunotherapy response and drug sensitivity of gastric cancer. In addition, we explored the role of TGM2 in promoting gastric cancer progression through in vitro experiments. We identified three ICD-associated subtypes by consensus clustering. The ICD gene was highly expressed in Cluster B. Compared with the other two subtypes, Cluster B had better prognosis, higher immune response signaling activity, massive immune cell infiltration and lower tumor purity. Immune checkpoint (ICP) and human leukocyte antigen (HLA) related genes were also highly expressed in Cluster B. In addition, we found that ICDRS is an effective indicator for predicting the prognosis and immune efficacy of STAD. The low ICDRS group has the characteristics of good prognosis, high tumor mutation burden (TMB), high microsatellite instability (MSI), and sensitivity to immunotherapy, while the high ICDRS group is prone to immune escape and immunotherapy resistance. In addition, we found that down-regulating TGM2 gene can inhibit the proliferation and migration of gastric cancer cells through in vitro experiments. Our study found that the model based on ICD features is helpful to clarify the TME characteristics of STAD, and has important clinical significance for evaluating the prognosis and immunotherapy response of STAD patients. TGM2 plays an important role in the progression of STAD, suggesting that TGM2 can be used as a new target for the treatment of STAD.

Immunological characteristics of immunogenic cell death genes and malignant progression driving roles of TLR4 in anaplastic thyroid carcinoma

Anaplastic thyroid carcinoma (ATC) was a rare malignancy featured with the weak immunotherapeutic response. So far, disorders of immunogenic cell death genes (ICDGs) were identified as the driving factors in cancer progression, while their roles in ATC remained poorly clear. Datasets analysis identified that most ICDGs were high expressed in ATC, while DE-ICDGs were located in module c1_112, which was mainly enriched in Toll-like receptor signalings. Subsequently, the ICD score was established to classify ATC samples into the high and low ICD score groups, and function analysis indicated that high ICD score was associated with the immune characteristics. The high ICD score group had higher proportions of specific immune and stromal cells, as well as increased expression of immune checkpoints. Additionally, TLR4, ENTPD1, LY96, CASP1 and PDIA3 were identified as the dynamic signature in the malignant progression of ATC. Notably, TLR4 was significantly upregulated in ATC tissues, associated with poor prognosis. Silence of TLR4 inhibited the proliferation, metastasis and clone formation of ATC cells. Eventually, silence of TLR4 synergistically enhanced paclitaxel-induced proliferation inhibition, apoptosis, CALR exposure and release of ATP. Our findings highlighted that the aberrant expression of TLR4 drove the malignant progression of ATC, which contributed to our understanding of the roles of ICDGs in ATC.

In Situ Cocktail Nanovaccine for Cancer Immunotherapy

In situ vaccination is a desirable strategy for cancer immunotherapy due to its convenience and capacity to target tumor antigens. Here, an in situ nanovaccine based on a cationic peptide with cholesterol-modified, DP7-C, for cancer immunotherapy is rationally designed, and developed a cancer nanovaccine that is easy to preparate. The nanovaccine includes cocktail small interfering RNAs (siRNAs) and immunologic adjuvant CpG ODNs, has synergistic effect in the cancer treatment. This nanovaccine can induce tumor cell death, promote antigen presentation and relieve immune suppression in the tumor microenvironment (TME). Moreover, this nanovaccine is administered to CT26 (hot) and B16F10 (cold) tumor model mice, in which it targeted the primary tumors and induced systemic antitumor immunity to inhibit metastasis. It is validated that the nanovaccine can convert cold tumors into hot tumors. Furthermore, the nanovaccine increased the immune response to anti-PD-1 therapy by modulating the TME in both CT26- and B16F10-tumor-bearing mice. The siRNA cocktail/CpG ODN/self-assembling peptide nanovaccine is a simple and universal tool that can effectively generate specific tumor cell antigens and can be combined with immuno-oncology agents to enhance antitumor immune activity. The versatile methodology provides an alternative approach for developing cancer nanovaccines.

Targeting TNFAIP2 induces immunogenic cell death and sensitizes glioblastoma multiforme to anti-PD-1 therapy

BACKGROUND

The efficacy of current immunotherapeutic strategies for patients with glioblastoma multiforme (GBM) remains unsatisfactory. The purpose of this study was to investigate the correlation between tumor necrosis factor alpha-induced protein 2 (TNFAIP2) and immunogenic cell death (ICD) in GBM, and to examine the effect of TNFAIP2 knockdown and anti-PD-1 combination treatment in a mouse glioma model.

METHODS

The CGGA and TCGA databases were used to explore the possible function of TNFAIP2 in GBM. Multiplex immunohistochemistry (mIHC) staining was performed to detect the immune infiltration of tissues. Western blot, quantitative real-time polymerase chain reaction (qRT-PCR), flow cytometry, and enzyme linked immunosorbent assay (ELISA) were utilized to detect the release of damage-associated molecular patterns (DAMPs) and the activation of the immune response. A mouse glioma model was applied to examine the induction of immune response.

RESULTS

In vitro and in vivo studies demonstrated that TNFAIP2 knockdown increased the surface exposure of calreticulin (CALR), heat shock protein 70 kDa (HSP70), and heat shock protein 90 kDa (HSP90) in GBM cell lines, thereby inducing immunogenic cell death (ICD). Importantly, the study found that TNFAIP2 knockdown in combination with anti-PD-1 therapy significantly improved the overall survival of glioma in a mouse model.

CONCLUSIONS

TNFAIP2 knockdown induces ICD by downregulating TNFAIP2 in GBM. In addition, TNFAIP2 knockdown sensitized glioma to anti-PD-1 therapy. Hence, targeting TNFAIP2 alone or in combination with anti-PD-1 therapy may be a potential strategy for GBM treatment through ICD.

Nano-enabled colorectal cancer therapy

Colorectal cancer (CRC), one of the most common and deadliest diseases worldwide, poses a great health threat and social burden. The clinical treatments of CRC encompassing surgery, chemotherapy, and radiotherapy are challenged with toxicity, therapy resistance, and recurrence. In the past two decades, targeted therapy and immunotherapy have greatly improved the therapeutic benefits of CRC patients but they still suffer from drug resistance and low response rates. Very recently, gut microbiota regulation has exhibited a great potential in preventing and treating CRC, as well as in modulating the efficacy and toxicity of chemotherapy and immunotherapy. In this review, we provide a cutting-edge summary of nanomedicine-based treatment in colorectal cancer, highlighting the recent progress of oral and systemic tumor-targeting and/or tumor-activatable drug delivery systems as well as novel therapeutic strategies against CRC, including nano-sensitizing immunotherapy, anti-inflammation, gut microbiota modulation therapy, etc. Finally, the recent endeavors to address therapy resistance, metastasis, and recurrence in CRC were discussed. We hope this review could offer insight into the design and development of nanomedicines for CRC and beyond.

Comprehensive analysis of ICD-related lncRNAs in predicting risk stratification, clinical prognosis and immune response for breast cancer

BACKGROUND

Breast cancer (BRCA) represents a significant threat with high mortality rates due to relapse, metastasis, and chemotherapy resistance. As a regulated cell death process characterized by the induction of immunogenic signals, immunogenic cell death (ICD) has been identified as an effective anti-tumorigenesis approach. However, the comprehensive study and its clinical value of ICD-related lncRNAs in BRCA is still missing.

METHODS

The transcriptome matrix and corresponding clinical information of BRCA patients were obtained from The Cancer Genome Atlas (TCGA) database. Pearson correlation analysis was performed to identify ICD-related lncRNAs (ICDRLs). To determine the prognostic value of the identified ICDRLs, univariate Cox regression analysis, LASSO algorithm, and multivariate Cox regression analysis were employed to construct a risk model. The prognostic risk model was subsequently evaluated using univariate and multivariate Cox regression analysis, as well as Nomogram analysis. In vitro experiments were also conducted to validate the bioinformatics findings using quantitative real-time PCR (qRT-PCR).

RESULTS

We established a prognostic risk signature consisting of five ICDRLs. The prognostic value of this model was subsequently confirmed in guiding BRCA prognostic stratification. Furthermore, we explored the correlation of the risk score with various clinical characteristics and chemotherapy response. qRT-PCR result confirmed the abnormal expression of ICDRLs, which was consistent with the bioinformatics data.

CONCLUSIONS

Our findings provide evidence of the critical role of ICDRLs in BRCA and offer a novel perspective for exploring precise treatment options for BRCA patients.

Reinforcing the immunogenic cell death to enhance cancer immunotherapy efficacy

Immunogenic cell death (ICD) has been a revolutionary modality in cancer treatment since it kills primary tumors and prevents recurrent malignancy simultaneously. ICD represents a particular form of cancer cell death accompanied by production of damage-associated molecular patterns (DAMPs) that can be recognized by pattern recognition receptors (PRRs), which enhances infiltration of effector T cells and potentiates antitumor immune responses. Various treatment methods can elicit ICD involving chemo- and radio-therapy, phototherapy and nanotechnology to efficiently convert dead cancer cells into vaccines and trigger the antigen-specific immune responses. Nevertheless, the efficacy of ICD-induced therapies is restrained due to low accumulation in the tumor sites and damage of normal tissues. Thus, researchers have been devoted to overcoming these problems with novel materials and strategies. In this review, current knowledge on different ICD modalities, various ICD inducers, development and application of novel ICD-inducing strategies are summarized. Moreover, the prospects and challenges are briefly outlined to provide reference for future design of novel immunotherapy based on ICD effect.

Promotion of ICD via Nanotechnology

Immunotherapy represents the most promising treatment strategy for cancer, but suffers from compromised therapeutic efficiency due to low immune activity of tumor cells and an immunosuppressive microenvironment, which significantly hampers the clinical translations of this treatment strategy. To promote immunotherapy with desired therapeutic efficiency, immunogenic cell death (ICD), a particular type of death capable of reshaping body's antitumor immune activity, has drawn considerable attention due to the potential to stimulate a potent immune response. Still, the potential of ICD effect remains unsatisfactory because of the intricate tumor microenvironment and multiple drawbacks of the used inducing agents. ICD has been thoroughly reviewed so far with a general classification of ICD as a kind of immunotherapy strategy and repeated discussion of the related mechanism. However, there are no published reviews, to the authors' knowledge, providing a systematic summarization on the enhancement of ICD via nanotechnology. For this purpose, this review first discusses the four stages of ICD according to the development mechanisms, followed by a comprehensive description on the use of nanotechnology to enhance ICD in the corresponding four stages. The challenges of ICD inducers and possible solutions are finally summarized for future ICD-based enhanced immunotherapy.

Immunogenic cell death-based prognostic model for predicting the response to immunotherapy and common therapy in lung adenocarcinoma

Lung adenocarcinoma (LUAD) is a malignant tumor in the respiratory system. The efficacy of current treatment modalities varies greatly, and individualization is evident. Therefore, finding biomarkers for predicting treatment prognosis and providing reference and guidance for formulating treatment options is urgent. Cancer immunotherapy has made distinct progress in the past decades and has a significant effect on LUAD. Immunogenic Cell Death (ICD) can reshape the tumor's immune microenvironment, contributing to immunotherapy. Thus, exploring ICD biomarkers to construct a prognostic model might help individualized treatments. We used a lung adenocarcinoma (LUAD) dataset to identify ICD-related differentially expressed genes (DEGs). Then, these DEGs were clustered and divided into subgroups. We also performed variance analysis in different dimensions. Further, we established and validated a prognostic model by LASSO Cox regression analysis. The risk score in this model was used to evaluate prognostic differences by survival analysis. The treatment prognosis of various therapies were also predicted. LUAD samples were divided into two subgroups. The ICD-high subgroup was related to an immune-hot phenotype more sensitive to immunotherapy. The prognostic model was constructed based on six ICD-related DEGs. We found that high-risk score patients responded better to immunotherapy. The ICD prognostic model was validated as a standalone factor to evaluate the ICD subtype of individual LUAD patients, which might contribute to more effective therapies.

Coming of Age: Targeting Cyclin K in Cancers

Cyclins and cyclin-dependent kinases (CDKs) play versatile roles in promoting the hallmarks of cancer. Therefore, cyclins and CDKs have been widely studied and targeted in cancer treatment, with four CDK4/6 inhibitors being approved by the FDA and many other inhibitors being examined in clinical trials. The specific purpose of this review is to delineate the role and therapeutic potential of Cyclin K in cancers. Studies have shown that Cyclin K regulates many essential biological processes, including the DNA damage response, mitosis, and pre-replicative complex assembly, and is critical in both cancer cell growth and therapeutic resistance. Importantly, the druggability of Cyclin K has been demonstrated in an increasing number of studies that identify novel opportunities for its use in cancer treatment. This review first introduces the basic features and translational value of human cyclins and CDKs. Next, the discovery, phosphorylation targets, and related functional significance of Cyclin K-CDK12/13 complexes in cancer are detailed. This review then provides a summary of current Cyclin K-associated cancer studies, with an emphasis on the available Cyclin K-targeting drugs. Finally, the current knowledge gaps regarding the potential of Cyclin K in cancers are discussed, along with interesting directions for future investigation.

PTPRC promoted CD8+ T cell mediated tumor immunity and drug sensitivity in breast cancer: based on pan-cancer analysis and artificial intelligence modeling of immunogenic cell death-based drug sensitivity stratification

Background

Immunogenic cell death (ICD) is a result of immune cell infiltration (ICI)-mediated cell death, which is also a novel acknowledgment to regulate cellular stressor-mediated cell death, including drug therapy and radiotherapy.

Methods

In this study, TCGA and GEO data cohorts were put into artificial intelligence (AI) to identify ICD subtypes, and in vitro experiments were performed.

Results

Gene expression, prognosis, tumor immunity, and drug sensitivity showed significance among ICD subgroups, Besides, a 14-gene-based AI model was able to represent the genome-based drug sensitivity prediction, which was further verified in clinical trials. Network analysis revealed that PTPRC was the pivotal gene in regulating drug sensitivity by regulating CD8+ T cell infiltration. Through in vitro experiments, intracellular down-regulation of PTPRC enhanced paclitaxel tolerance in triple breast cancer (TNBC) cell lines. Meanwhile, the expression level of PTPRC was positively correlated with CD8+ T cell infiltration. Furthermore, the down-regulation of PTPRC increased the level of TNBC-derived PD-L1 and IL2.

Discussion

ICD-based subtype clustering of pan-cancer was helpful to evaluate chemotherapy sensitivity and immune cell infiltration, and PTPRC was a potential target to against drug resistance of breast cancer.

Analyzing molecular typing and clinical application of immunogenic cell death-related genes in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is considered one of the most common cancers, characterized by low early detection and high mortality rates, and is a global health challenge. Immunogenic cell death (ICD) is defined as a specific type of regulated cell death (RCD) capable of reshaping the tumor immune microenvironment by releasing danger signals that trigger immune responses, which would contribute to immunotherapy.

METHODS

The ICD gene sets were collected from the literature. We collected expression data and clinical information from public databases for the HCC samples in our study. Data processing and mapping were performed using R software to analyze the differences in biological characteristics between different subgroups. The expression of the ICD representative gene in clinical specimens was assessed by immunohistochemistry, and the role of the representative gene in HCC was evaluated by various in vitro assays, including qRT-PCR, colony formation, and CCK8 assay. Lasso-Cox regression was used to screen prognosis-related genes, and an ICD-related risk model (ICDRM) was constructed. To improve the clinical value of ICDRM, Nomograms and calibration curves were created to predict survival probabilities. Finally, the critical gene of ICDRM was further investigated through pan-cancer analysis and single-cell analysis.

RESULTS

We identified two ICD clusters that differed significantly in terms of survival, biological function, and immune infiltration. As well as assessing the immune microenvironment of tumors in HCC patients, we demonstrate that ICDRM can differentiate ICD clusters and predict the prognosis and effectiveness of therapy. High-risk subpopulations are characterized by high TMB, suppressed immunity, and poor survival and response to immunotherapy, whereas the opposite is true for low-risk subpopulations.

CONCLUSIONS

This study reveals the potential impact of ICDRM on the tumor microenvironment (TME), immune infiltration, and prognosis of HCC patients, but also a potential tool for predicting prognosis.

Chemo-Immunotherapy: A New Trend in Cancer Treatment

Chemotherapy has been the basis of advanced cancer treatment for decades. This therapy has largely been considered immunosuppressive, yet accumulated preclinical and clinical evidence shows that certain chemotherapeutic drugs, under defined conditions, may stimulate antitumor immunity and potentiate immune checkpoint inhibitor (ICI)-based therapy. Its effectiveness has been highlighted by recent regulatory approvals of various combinations of chemotherapy with ICIs in several tumors, particularly in some difficult-to-treat cancers. This review discusses the immune modulatory properties of chemotherapy and how they may be harnessed to develop novel chemo-immunotherapy combinations. It also highlights the key determinants of the success of chemo-immunotherapy and provides an overview of the combined chemo-immunotherapies that have been clinically approved.

Significance of Immunogenic Cell Death-Related Prognostic Gene Signature in Cervical Cancer Prognosis and Anti-Tumor Immunity

Background

Immunogenic cell death (ICD) can reshape the immune microenvironment of tumors. Driven by stressful pressure, by directly destroying tumor cells and activating the body's adaptive immunity, ICD acts as a modulator of cell death, enabling the body to generate an anti-tumor immune response that produces a more effective therapeutic effect, while tumor cells are driven to kill. Hence, this research aimed to find and evaluate ICD-related genetic signatures as cervical cancer (CC) prognostic factors.

Methods

Data of CC patients from the Tumor Genome Atlas (TCGA) were used as the basis to obtain immunogenic cell-death-related prognostic genes (IPGs) in patients with CC, using the least absolute shrinkage and selection operator and Cox regression screening, and the IPGs scoring system was constructed to classify patients into high- and low-risk groups, with the Gene Expression Omnibus (GEO) dataset as the validation group. Finally, the difference analysis of single-sample gene set enrichment analysis, tumor microenvironment (TME), immune cells, tumor mutational burden, and chemotherapeutic drug sensitivity between the high-risk and low-risk groups was investigated.

Results

A prognostic model with four IPGs (PDIA3, CASP8, IL1, and LY96) was developed, and it was found that the group of CC patients with a higher risk score of IPGs expression had a lower survival rate. Single and multifactor Cox regression analysis also showed that this risk score was a reliable predictor of overall survival. In comparison to the low-risk group, the high-risk group had lower TME scores and immune cell infiltration, and gene set variation analysis showed that immune-related pathways were more enriched in the high-risk group.

Conclusion

A risk model constructed from four IPGs can independently predict the prognosis of CC patients and recommend more appropriate immunotherapy strategies for patients.

Kinase inhibitors: Opportunities for small molecule anticancer immunotherapies

As the fifth pillar of cancer treatment, immunotherapy has dramatically changed the paradigm of therapeutic strategies by focusing on the host's immune system. In the long road of immunotherapy development, the identification of immune-modulatory effects for kinase inhibitors opened a new chapter in this therapeutic approach. These small molecule inhibitors not only directly eradicate tumors by targeting essential proteins of cell survival and proliferation but can also drive immune responses against malignant cells. This review summarizes the current standings and challenges of kinase inhibitors in immunotherapy, either as a single agent or in a combined modality.

Genetic dysregulation of immunologic and oncogenic signaling pathways associated with tumor-intrinsic immune resistance: a molecular basis for combination targeted therapy-immunotherapy for cancer

Since the turn of the century, advances in targeted therapy and immunotherapy have revolutionized the treatment of cancer. Although these approaches have far outperformed traditional therapies in various clinical settings, both remain plagued by mechanisms of innate and acquired resistance that limit therapeutic efficacy in many patients. With a focus on tumor-intrinsic resistance to immunotherapy, this review highlights our current understanding of the immunologic and oncogenic pathways whose genetic dysregulation in cancer cells enables immune escape. Emphasis is placed on genomic, epigenomic, transcriptomic, and proteomic aberrations that influence the activity of these pathways in the context of immune resistance. Specifically, the role of pathways that govern interferon signaling, antigen processing and presentation, and immunologic cell death as determinants of tumor immune susceptibility are discussed. Likewise, mechanisms of tumor immune resistance mediated by dysregulated RAS-MAPK, WNT, PI3K-AKT-mTOR, and cell cycle pathways are described. Finally, this review highlights the ways in which recent insight into genetic dysregulation of these immunologic and oncogenic signaling pathways is informing the design of combination targeted therapy-immunotherapy regimens that aim to restore immune susceptibility of cancer cells by overcoming resistance mechanisms that often limit the success of monotherapies.

An Overview of CDK Enzyme Inhibitors in Cancer Therapy

The ability to address the cell cycle in cancer therapy brings up new medication development possibilities. Cyclin-dependent kinases are a group of proteins that control the progression of the cell cycle. The CDK/cyclin complexes are activated when specific CDK sites are phosphorylated. Because of their non-selectivity and severe toxicity, most first-generation CDK inhibitors (also known as pan-CDK inhibitors) have not been authorized for clinical usage. Despite this, significant progress has been made in allowing pan-CDK inhibitors to be employed in clinical settings. Pan-CDK inhibitors' toxicity and side effects have been lowered in recent years because of the introduction of combination therapy techniques. As a result of this, pan-CDK inhibitors have regained a lot of clinical potential as a combination therapy approach. The CDK family members have been introduced in this overview, and their important roles in cell cycle control have been discussed. Then, we have described the current state of CDK inhibitor research, with a focus on inhibitors other than CDK4/6. We have mentioned first-generation pan-CDKIs, flavopiridol and roscovitine, as well as second-generation CDKIs, dinaciclib, P276-00, AT7519, TG02, roniciclib, and RGB-286638, based on their research phases, clinical trials, and cancer targeting. CDKIs are CDK4/6, CDK7, CDK9, and CDK12 inhibitors. Finally, we have looked into the efficacy of CDK inhibitors and PD1/PDL1 antibodies when used together, which could lead to the development of a viable cancer treatment strategy.

Transcription-associated cyclin-dependent kinase 12 (CDK12) as a potential target for cancer therapy

Cyclin-dependent kinase 12 (CDK12), a transcription-related cyclin dependent kinase (CDK), plays a momentous part in multitudinous biological functions, such as replication, transcription initiation to elongation and termination, precursor mRNA (pre-mRNA) splicing, intron polyadenylation (IPA), and translation. CDK12 can act as a tumour suppressor or oncogene in disparate cellular environments, and its dysregulation likely provokes tumorigenesis. A comprehensive understanding of CDK12 will tremendously facilitate the exploitation of novel tactics for the treatment and precaution of cancer. Currently, CDK12 inhibitors are nonspecific and nonselective, which profoundly hinders the pharmacological target validation and drug exploitation process. Herein, we summarize the newly comprehension of the biological functions of CDK12 with a focus on recently emerged advancements of CDK12-associated therapeutic approaches in cancers.

CDK regulators—Cell cycle progression or apoptosis—Scenarios in normal cells and cancerous cells

Serine/threonine kinases called cyclin-dependent kinases (CDKs) interact with cyclins and CDK inhibitors (CKIs) to control the catalytic activity. CDKs are essential controllers of RNA transcription and cell cycle advancement. The ubiquitous overactivity of the cell cycle CDKs is caused by a number of genetic and epigenetic processes in human cancer, and their suppression can result in both cell cycle arrest and apoptosis. This review focused on CDKs, describing their kinase activity, their role in phosphorylation inhibition, and CDK inhibitory proteins (CIP/KIP, INK 4, RPIC). We next compared the role of different CDKs, mainly p21, p27, p57, p16, p15, p18, and p19, in the cell cycle and apoptosis in cancer cells with respect to normal cells. The current work also draws attention to the use of CDKIs as therapeutics, overcoming the pharmacokinetic barriers of pan-CDK inhibitors, analyze new chemical classes that are effective at attacking the CDKs that control the cell cycle (cdk4/6 or cdk2). It also discusses CDKI's drawbacks and its combination therapy against cancer patients. These findings collectively demonstrate the complexity of cancer cell cycles and the need for targeted therapeutic intervention. In order to slow the progression of the disease or enhance clinical outcomes, new medicines may be discovered by researching the relationship between cell death and cell proliferation.

Research progress in inducing immunogenic cell death of tumor cells

Immunogenic cell death (ICD) is a regulated cell death (RCD) pathway. In response to physical and chemical signals, tumor cells activate specific signaling pathways that stimulate stress responses in the endoplasmic reticulum (ER) and expose damage-associated molecular patterns (DAMPs), which promote antitumor immune responses. As a result, the tumor microenvironment is altered, and many tumor cells are killed. The ICD response in tumor cells requires inducers. These inducers can be from different sources and contribute to the development of the ICD either indirectly or directly. The combination of ICD inducers with other tumor treatments further enhances the immune response in tumor cells, and more tumor cells are killed; however, it also produces side effects of varying severity. New induction methods based on nanotechnology improve the antitumor ability and significantly reduces side effects because they can target tumor cells precisely. In this review, we introduce the characteristics and mechanisms of ICD responses in tumor cells and the DAMPs associated with ICD responses, summarize the current methods of inducing ICD response in tumor cells in five distinct categories: chemical sources, physical sources, pathogenic sources, combination therapies, and innovative therapies. At the same time, we introduce the limitations of current ICD inducers and make a summary of the use of ICD responses in clinical trials. Finally, we provide an outlook on the future of ICD inducer development and provide some constructive suggestions.

Development and validation of immunogenic cell death-related signature for predicting the prognosis and immune landscape of uveal melanoma

INTRODUCTION

Uveal melanoma (UM) is the most common primary intraocular malignant tumor in adults, and the main treatment for UM is currently surgery and plaque brachytherapy. UM is highly susceptible to metastasis, which eventually occurs in nearly half of all patients; once metastasis occurs, patients have a poor prognosis and the condition is difficult to treat. Therefore, the identification of new and effective UM biomarkers is vital for the application of therapeutic strategies. Immunogenic cell death (ICD) is a type of regulatory cell death that activates adaptive immune responses and generates long-term immunological memory. ICD can promote antitumor immunity, which may be a potential immunotherapeutic strategy for UM.

METHODS

The data of UM from the Cancer Genome Atlas (TCGA) was used as a training set and the data from Gene Expression Omnibus (GEO) was used as a validation set. To determine the expression pattern of ICD-related genes in UM, survival analysis and difference analysis was conducted. The ICD-related risk signature was constructed by employing the least absolute shrinkage and selection operator (LASSO) Cox regression. Subsequently, immune profile and somatic mutation analysis were performed. In addition, cell experiments were performed to verify the role of immunogenic cell death-related genes in UM.

RESULTS

In this study, we analyzed the relationship between ICD-related gene expression and UM patient prognosis, somatic mutations, and the tumor immune microenvironment. Importantly, we constructed a 5-gene ICD-related risk signature and confirmed it as a novel prognostic biomarker in UM patients. We found that the high-risk group had more immune cell infiltration and a worse prognosis than the low-risk group. In cellular experiments, we confirmed the high expression of FOXP3 inMUM2B andOCM-1A cell lines and that knockdown of FOXP3 markedly inhibited the proliferation of UM tumor cells.

DISCUSSION

ICD-related genes play a critical role in the tumor immune microenvironment. Our results may contribute to the development of effective immunotherapies.

Immunogenic cell death-related classifications in breast cancer identify precise immunotherapy biomarkers and enable prognostic stratification

Background: Immunogenic cell death (ICD) remodels the tumor immune microenvironment, plays an inherent role in tumor cell apoptosis, and promotes durable protective antitumor immunity. Currently, appropriate biomarker-based ICD immunotherapy for breast cancer (BC) is under active exploration. Methods: To determine the potential link between ICD genes and the clinical risk of BC, TCGA-BC was used as the training set and GSE58812 was used as the validation set. Gene expression, consistent clustering, enrichment analysis, and mutation omics analyses were performed to analyze the potential biological pathways of ICD genes involved in BC. Furthermore, a risk and prognosis model of ICD was constructed to evaluate the correlation between risk grade and immune infiltration, clinical stage, and survival prognosis. Results: We identified two ICD-related subtypes by consistent clustering and found that the C2 subtype was associated with good survival prognosis, abundant immune cell infiltration, and high activity of immune biological processes. Based on this, we constructed and validated an ICD risk and prognosis model of BC, including ATG5, HSP90AA1, PIK3CA, EIF2AK3, MYD88, IL1R1, and CD8A. This model can effectively predict the survival rate of patients with BC and is negatively correlated with the immune microenvironment and clinical stage. Conclusion: This study provides new insights into the role of ICD in BC. The novel classification risk model based on ICD in BC established in this study can aid in estimating the potential prognosis of patients with BC and the clinical outcomes of immunotherapy and postulates targets that are more useful in comprehensive treatment strategies.

Tubular-specific CDK12 knockout causes a defect in urine concentration due to premature cleavage of the slc12a1 gene

Cyclin-dependent kinase 12 (CDK12) plays a critical role in regulating gene transcription. CDK12 inhibition is a potential anticancer therapeutic strategy. However, several clinical trials have shown that CDK inhibitors might cause renal dysfunction and electrolyte disorders. CDK12 is abundant in renal tubular epithelial cells (RTECs), but the exact role of CDK12 in renal physiology remains unclear. Genetic knockout of CDK12 in mouse RTECs causes polydipsia, polyuria, and hydronephrosis. This phenotype is caused by defects in water reabsorption that are the result of reduced Na-K-2Cl cotransporter 2 (NKCC2) levels in the kidney. In addition, CKD12 knockout causes an increase in Slc12a1 (which encodes NKCC2) intronic polyadenylation events, which results in Slc12a1 truncated transcript production and NKCC2 downregulation. These findings provide novel insight into CDK12 being necessary for maintaining renal homeostasis by regulating NKCC2 transcription, which explains the critical water and electrolyte disturbance that occurs during the application of CDK12 inhibitors for cancer treatment. Therefore, there are safety concerns about the clinical use of these new anticancer drugs.

CDK12 orchestrates super-enhancer-associated CCDC137 transcription to direct hepatic metastasis in colorectal cancer

BACKGROUND

Hepatic metastasis is the primary and direct cause of death in individuals with colorectal cancer (CRC) attribute to lack of effective therapeutic targets. The present study aimed to identify potential druggable candidate targets for patients with liver metastatic CRC.

METHODS

The transcriptional profiles of super-enhancers (SEs) in primary and liver metastatic CRC were evaluated in publicly accessible CRC datasets. Immunohistochemistry of human CRC tissues was conducted to determine the expression level of CDK12. Cellular proliferation, survival and stemness were examined upon CDK12 inhibition by shCDK12 or a selective CDK12 inhibitor named SR-4835 with multiple in vitro and in vivo assays. RNA sequencing and bioinformatics analyses were carried out to investigate the mechanisms of CDK12 inhibition in CRC cells.

RESULTS

We identified CDK12 as a driver gene for direct hepatic metastasis in CRC. Suppression of CDK12 led to robust inhibition of proliferation, survival and stemness. Mechanistically, CDK12 intervention preferentially repressed the transcription of SE-associated genes. Integration of the SE landscape and RNA sequencing, BCL2L1 and CCDC137 were identified as SE-associated oncogenic genes to strengthen the abilities of cellular survival, proliferation and stemness, eventually increasing liver metastasis of CRC.

CONCLUSIONS

Our data highlight the potential of CDK12 and SE-associated oncogenic transcripts as therapeutic targets for patients with liver metastatic CRC.

Targeting the Heterogeneous Genomic Landscape in Triple-Negative Breast Cancer through Inhibitors of the Transcriptional Machinery

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer defined by lack of the estrogen, progesterone and human epidermal growth factor receptor 2. Although TNBC tumors contain a wide variety of oncogenic mutations and copy number alterations, the direct targeting of these alterations has failed to substantially improve therapeutic efficacy. This efficacy is strongly limited by interpatient and intratumor heterogeneity, and thereby a lack in uniformity of targetable drivers. Most of these genetic abnormalities eventually drive specific transcriptional programs, which may be a general underlying vulnerability. Currently, there are multiple selective inhibitors, which target the transcriptional machinery through transcriptional cyclin-dependent kinases (CDKs) 7, 8, 9, 12 and 13 and bromodomain extra-terminal motif (BET) proteins, including BRD4. In this review, we discuss how inhibitors of the transcriptional machinery can effectively target genetic abnormalities in TNBC, and how these abnormalities can influence sensitivity to these inhibitors. These inhibitors target the genomic landscape in TNBC by specifically suppressing MYC-driven transcription, inducing further DNA damage, improving anti-cancer immunity, and preventing drug resistance against MAPK and PI3K-targeted therapies. Because the transcriptional machinery enables transcription and propagation of multiple cancer drivers, it may be a promising target for (combination) treatment, especially of heterogeneous malignancies, including TNBC.

Current progress and novel strategies that target CDK12 for drug discovery

CDK12 is a cyclin-dependent kinase that plays critical roles in DNA replication, transcription, mRNA splicing, and DNA damage repair. CDK12 genomic changes, including mutation, amplification, deletion, and fusion, lead to various cancers, such as colorectal cancer, gastric cancer, and ovarian cancer. An increasing number of CDK12 inhibitors have been reported since CDK12 was identified as a biomarker and cancer therapeutic target. A major challenge lies in that CDK12 and CDK13 share highly similar sequences, which leads to great difficulties in the development of highly selective CDK12 inhibitors. In recent years, great efforts were made in developing selective CDK12 blockers. Techniques including PROTAC and molecular glue degraders were also applied to facilitate their development. Also, the drug combination strategy of CDK12 small molecule inhibitors were studied. This review discusses the latest studies on CDK12 inhibitors and analyzes their structure-activity relationships, shedding light on their further development.

Cyclin-dependent kinase inhibition and its intersection with immunotherapy in breast cancer: more than CDK4/6 inhibition

INTRODUCTION

Cyclin-dependent kinase (CDK) 4/6 inhibitors (CDK4/6i) have had clinical success in treating hormone receptor-positive, human epidermal growth factor receptor 2-negative metastatic breast cancer. Notably, CDK4/6i have expanded to the neoadjuvant setting for early breast cancer and other cancer types and potently synergize with immunotherapy. Other CDKs, including CDK7, CDK9, and CDK12/13, mainly function in transcriptional processes as well as cell cycle regulation, RNA splicing, and DNA damage response. Inhibiting these CDKs aids in suppressing tumors, reversing drug resistance, increasing drug sensitivity, and enhancing anti-tumor immunity in breast cancer.

AREAS COVERED

We reviewed the applications of CDK4/6i, CDK7i, CDK9i and CDK12/13i for various breast cancer subtypes and their potentials for combination with immunotherapy. A literature search of PubMed, Embase, and Web of Science was conducted in April 2022.

EXPERT OPINION

The use of CDK4/6i represents a major milestone in breast cancer treatment. Moreover, transcription-related CDKs play critical roles in tumor development and are promising therapeutic targets for breast cancer. Some relevant clinical studies are underway. More specific and efficient CDKis will undoubtedly be developed and clinically tested. Characterization of their immune-priming effects will promote the development of combination therapies consisting of CDKi and immunotherapy.

Huaier Induces Immunogenic Cell Death Via CircCLASP1/PKR/eIF2α Signaling Pathway in Triple Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most lethal breast cancer subtype owing to the lack of targeted therapeutic strategies. Immunogenic cell death (ICD), a modality of regulated cancer cell death, offered a novel option for TNBC via augmenting tumor immunogenic microenvironment. However, few ICD-inducing agents are currently available. Here, we showed that Trametes robiniophila Murr (Huaier) triggered ICD in TNBC cells by promoting cell surface calreticulin (CRT) exposure, and increasing release of adenosine triphosphate (ATP) and high-mobility group protein B1 (HMGB1). Co-culturing with Huaier-treated TNBC cells efficiently enhanced the maturation of dendritic cells (DCs), which was further validated via cell-based vaccination assay. In the xenograft mouse model, oral administration of Huaier led to tumor-infiltrating lymphocytes (TILs) accumulation and significantly delayed tumor growth. Besides, depletion of endogenous T cells obviously abrogated the effect. Mechanically, Huaier could elicit endoplasmic reticulum (ER) stress-associated ICD through eIF2α signaling pathway. Further studies revealed that circCLASP1 was involved in the Huaier-induced immunogenicity by binding with PKR in the cytoplasm and thus blocking its degradation. Taken together, we highlighted an essential role of circCLASP1/PKR/eIF2α axis in Huaier-induced ICD. The findings of our study carried significant translational potential that Huaier might serve as a promising option to achieve long-term tumor remission in patients with TNBC.

Carbon ion radiotherapy triggers immunogenic cell death and sensitizes melanoma to anti-PD-1 therapy in mice

Carbon ion radiotherapy (CIRT) is an emerging type of radiotherapy for the treatment of solid tumors. In recent years, evidence accumulated that CIRT improves the therapeutic outcome in patients with otherwise poor response to immune checkpoint blockade. Here, we aimed at identifying the underlying mechanisms of CIRT-induced tumor immunogenicity and treatment efficacy. We used human U2OS osteosarcoma cells for the in vitro assessment of immunogenic cell death and established several in vivo models of melanoma in mice. We treated the animals with conventional radiation, CIRT, PD-1-targeting immune checkpoint blockade or a sequential combinations of radiotherapy with checkpoint blockade. We utilized flow cytometry, polyacrylamide gel electrophoresis (PAGE) and immunoblot analysis, immunofluorescence, immunohistochemistry, as well as enzyme-linked immunosorbent assays (ELISA) to assess biomarkers of immunogenic cell death in vitro. Treatment efficacy was studied by tumor growth assessment and the tumor immune infiltrate was analyzed by flow cytometry and immunohistochemistry. Compared with conventional radioimmunotherapy, the combination of CIRT with anti-PD-1 more efficiently triggered traits of immunogenic cell death including the exposure of calreticulin, the release of adenosine triphosphate (ATP), the exodus of high-mobility group box 1 (HMGB1) as well as the induction of type-1 interferon responses. In addition, CIRT plus anti-PD-1 led to an increased infiltration of CD4⁺, and CD8⁺ lymphocytes into the tumor bed, significantly decreased tumor growth and prolonged survival of melanoma bearing mice. We herein provide evidence that CIRT-triggered immunogenic cell death, enhanced tumor immunogenicity and improved the efficacy of subsequent anti-PD-1 immunotherapy.

Engineered exosomes as an in situ DC-primed vaccine to boost antitumor immunity in breast cancer

Background

Dendritic cells (DCs) are central for the initiation and regulation of innate and adaptive immunity in the tumor microenvironment. As such, many kinds of DC-targeted vaccines have been developed to improve cancer immunotherapy in numerous clinical trials. Targeted delivery of antigens and adjuvants to DCs in vivo represents an important approach for the development of DC vaccines. However, nonspecific activation of systemic DCs and the preparation of optimal immunodominant tumor antigens still represent major challenges.

Methods

We loaded the immunogenic cell death (ICD) inducers human neutrophil elastase (ELANE) and Hiltonol (TLR3 agonist) into α-lactalbumin (α-LA)-engineered breast cancer-derived exosomes to form an in situ DC vaccine (HELA-Exos). HELA-Exos were identified by transmission electron microscopy, nanoscale flow cytometry, and Western blot analysis. The targeting, killing, and immune activation effects of HELA-Exos were evaluated in vitro. The tumor suppressor and immune-activating effects of HELA-Exos were explored in immunocompetent mice and patient-derived organoids.

Results

HELA-Exos possessed a profound ability to specifically induce ICD in breast cancer cells. Adequate exposure to tumor antigens and Hiltonol following HELA-Exo-induced ICD of cancer cells activated type one conventional DCs (cDC1s) in situ and cross-primed tumor-reactive CD8⁺ T cell responses, leading to potent tumor inhibition in a poorly immunogenic triple negative breast cancer (TNBC) mouse xenograft model and patient-derived tumor organoids.

Conclusions

HELA-Exos exhibit potent antitumor activity in both a mouse model and human breast cancer organoids by promoting the activation of cDC1s in situ and thus improving the subsequent tumor-reactive CD8⁺ T cell responses. The strategy proposed here is promising for generating an in situ DC-primed vaccine and can be extended to various types of cancers.

Graphic Abstract

Scheme 1. Schematic illustration of HELA-Exos as an in situ DC-primed vaccine for breast cancer. (A) Allogenic breast cancer-derived exosomes isolated from MDA-MB-231 cells were genetically engineered to overexpress α-LA and simultaneously loaded with the ICD inducers ELANE and Hiltonol (TLR3 agonist) to generate HELA-Exos. (B) Mechanism by which HELA-Exos activate DCs in situ in a mouse xenograft model ofTNBC. HELA-Exos specifically homed to the TME and induced ICD in cancer cells, which resulted in the increased release of tumor antigens, Hiltonol, and DAMPs, as well as the uptake of dying tumor cells by cDC1s. The activated cDC1s then cross-primed tumor-reactive CD8+ T cell responses. (C) HELA-Exos activated DCs in situ in the breast cancer patient PBMC-autologous tumor organoid coculture system. Abbreviations: DCs: dendritic cells; α-LA: α-lactalbumin; HELA-Exos: Hiltonol-ELANE-α-LA-engineered exosomes; ICD: immunogenic cell death; ELANE: human neutrophil elastase; TLR3: Toll-like receptor 3; TNBC: triple-negative breast cancer; TME: tumor microenvironment; DAMPs: damage-associated molecular patterns; cDC1s: type 1 conventional dendritic cells; PBMCs: peripheral blood mononuclear cells

Supplementary Information

The online version contains supplementary material available at 10.1186/s12943-022-01515-x.

Targeting transcription cycles in cancer

Accurate control of gene expression is essential for normal development and dysregulation of transcription underpins cancer onset and progression. Similar to cell cycle regulation, RNA polymerase II-driven transcription can be considered as a unidirectional multistep cycle, with thousands of unique transcription cycles occurring in concert within each cell. Each transcription cycle comprises recruitment, initiation, pausing, elongation, termination and recycling stages that are tightly controlled by the coordinated action of transcriptional cyclin-dependent kinases and their cognate cyclins as well as the opposing activity of transcriptional phosphatases. Oncogenic dysregulation of transcription can entail defective control of gene expression, either at select loci or more globally, impacting a large proportion of the genome. The resultant dependency on the core-transcriptional machinery is believed to render 'transcriptionally addicted' cancers sensitive to perturbation of transcription. Based on these findings, small molecules targeting transcriptional cyclin-dependent kinases and associated proteins hold promise for the treatment of cancer. Here, we utilize the transcription cycles concept to explain how dysregulation of these finely tuned gene expression processes may drive tumorigenesis and how therapeutically beneficial responses may arise from global or selective transcriptional perturbation. This conceptual framework helps to explain tumour-selective transcriptional dependencies and facilitates the rational design of combination therapies.

Transcriptional cyclin-dependent kinases: Potential drug targets in cancer therapy

In the wake of the development of the concept of cell cycle and its limiting points, cyclin-dependent kinases (CDKs) are considered to play a central role in regulating cell cycle progression. Recent studies have strongly demonstrated that CDKs also has multiple functions, especially in response to extracellular and intracellular signals by interfering with transcriptional events. Consequently, how to inhibit their function has been a hot research topic. It is worth noting that the key role of CDKs in regulating transcription has been explored in recent years, but its related pharmacological targets are less developed, and most inhibitors have not entered the clinical stage. Accordingly, this perspective focus on the biological functions of transcription related CDKs and their complexes, some key upstream and downstream signals, and inhibitors for cancer treatment in recent years. In addition, some corresponding combined treatment strategies will provide a more novel perspective for future cancer remedy.

An Immunogenic Cell Death-Related Classification Predicts Prognosis and Response to Immunotherapy in Head and Neck Squamous Cell Carcinoma

Immunogenic cell death (ICD) has been classified as a form of regulated cell death (RCD) that is sufficient to activate an adaptive immune response. Accumulating evidence has demonstrated the ability of ICD to reshape the tumor immune microenvironment through the emission of danger signals or DAMPs, which may contribute to the immunotherapy. Currently, identification of ICD-associated biomarkers that stratify patients according to their benefit from ICD immunotherapy would be of great advantage. Here, we identified two ICD-associated subtypes by consensus clustering. ICD-high subtype was associated with the favorable clinical outcomes, abundant immune cell infiltration, and high activity of immune response signaling. Besides, we established and validated an ICD-related prognostic model that predicted the survival of HNSCC and was associated with tumor immune microenvironment. In conclusion, we established a new classification system of HNSCC based on ICD signatures. This stratification had significant clinical outcomes for estimating prognosis, as well as the immunotherapy of HNSCC patients

CDK13-Mediated Cell Cycle Disorder Promotes Tumorigenesis of High HMGA2 Expression Gastric Cancer

The inhibitor of CDK4/6 has been clinically used for treating certain types of cancer which are characterized by G0/G1 acceleration induced by the CDK4/6-RB1 pathway. On the contrary, the cell cycle–related molecules are abnormal in over 50% of the patients with gastric cancer (GC), but the efficiency of inhibiting CDK4/6 does not work well as it is expected. In our study, we found HMGA2 promotes GC through accelerating the S–G2/M phase transition, instead of G0/G1. We also found CDK13 is the direct target gene of HMGA2. Importantly, we analyzed 200 pairs of GC and the adjacent tissue and proved the positive relation between HMGA2 and CDK13; moreover, high expression of both genes predicts a poorer prognosis than the expression of single gene does. We explored the effect of the novel CDK12/13 inhibiting agent, SR-4835, on high HMGA2 expression GC and found inhibition of both genes jointly could reach a satisfied result. Therefore, we suggest that inhibition of CDK13 and HMGA2 simultaneously could be an effective strategy for high HMGA2 expression GC. To detect the expression of both genes simultaneously and individually could be of benefit to predict prognosis for GC.

Bullatacin triggers immunogenic cell death of colon cancer cells by activating endoplasmic reticulum chaperones

Background

It is well accepted that the immune system efficiently contributes to positive outcomes of chemotherapeutic cancer treatment by activating immunogenic cell death (ICD). However, only a limited number of ICD-inducing compounds are well characterized at present; therefore, identification of novel ICD inducers is urgently needed for cancer drug discovery, and the need is becoming increasingly urgent.

Methods

Herein, we assessed the antitumour activity of bullatacin by MTS assay and apoptosis assay. ICD biomarkers, such as calreticulin (CRT), high-mobility group protein B1 (HMGB-1), heat shock protein (HSP)70, HSP90 and ATP, were assessed by Western blotting, ELISA and flow cytometry. Western blot and qPCR assays were performed to explore the underlying mechanisms of bullatacin-induced ICD. Flow cytometry was used to detect macrophage phagocytosis.

Results

First, bullatacin induced apoptosis in both SW480 cells and HT-29 cells in a time-dependent manner at 10 nM, as assessed by flow cytometry. Moreover, Western blot and flow cytometry assays showed that CRT and HSP90 (biomarkers of early ICD) significantly accumulated on the cell membrane surface after approximately 6 h of treatment with bullatacin. In addition, ELISAs and Western blot assays showed that the second set of hallmarks required for ICD (HMGB1, HSP70 and HSP90) were released in the conditioned media of both SW480 and HT-29 cells after 36 h of treatment. Furthermore, qPCR and Western blot assays indicated that bullatacin triggered ICD via activation of the endoplasmic reticulum stress (ERS) signalling pathway. Finally, bullatacin promoted macrophage phagocytosis.

Conclusion

This study documents that bullatacin, a novel ICD inducer, triggers immunogenic tumour cell death by activating ERS even at a relatively low concentration in vitro.

Oxygen-carrying nanoparticle-based chemo-sonodynamic therapy for tumor suppression and autoimmunity activation

Sonodynamic therapy (SDT) is a promising non-invasive approach for cancer therapy. However, tumor hypoxia, a pathological characteristic of most solid tumor types, poses a major challenge in the application of SDT. In this study, a novel CD44 receptor-targeted and redox/ultrasound-responsive oxygen-carrying nanoplatform was constructed using chondroitin sulfate (CS), reactive oxygen species (ROS)-generating sonosensitizer Rhein (Rh), and perfluorocarbon (PFC). Perfluoroalkyl groups introduced into the structures preserved the oxygen carrying ability of PFC, increasing the oxygen content in B16F10 melanoma cells and enhancing the efficiency of SDT. Controlled nanoparticles without PFC generated lower ROS levels and exerted inferior tumor inhibition effects, both in vitro and in vivo, under ultrasound-treatment. In addition, SDT promoted immunogenic cell death (ICD) by inducing exposure of calreticulin (CRT) after treatment with CS-Rh-PFC nanoparticles (NPs). The immune system was significantly activated by docetaxel (DTX)-loaded NPs after SDT treatment due to the enhanced secretion of IFN-γ, TNF-α, IL-2 and IL-6 cytokines and tumor-infiltrating CD4+ and CD8+ T cell contents. Our findings support the utility of CS-Rh-PFC as an effective anti-tumor nanoplatform that promotes general immunity and accommodates multiple hydrophobic drugs to enhance the beneficial effects of chemo-SDT therapy.

CDK12 Promotes Cervical Cancer Progression through Enhancing Macrophage Infiltration

Cervical cancer (CC) is a commonly diagnosed and primary consideration of cancer patient death in female reproductive system malignancy. Cyclin-dependent kinase 12 (CDK12), as a transcription-associated CDK, plays important roles in tumor-promoting behaviors, whereas the underlying mechanisms of CDK12 in CC progression are still obscure. In this report, we investigated the role of CDK12 in cervical cancer. The current study identified CDK12 mRNA and protein expression remarkably upregulated in CC patients. Upregulated CDK12 was closely associated with CC progression and poor prognosis. In vitro and in vivo functional experiments showed that knockdown of CDK12 inhibited cancer cell proliferation and colony formation and promoted apoptosis. Further investigations demonstrated that CDK12 regulated the immune microenvironment to facilitate the progression of CC cells by promoting macrophage infiltration. Meanwhile, we first demonstrated that nuclear import of CDK12 is mediated by TNPO1 and might be a new therapeutic target in oncology. Collectively, this study pointed out the potential of CDK12 to serve as a novel therapeutic target in restricting CC proliferation and cell cycle process through promoting macrophage infiltration.

Pingyangmycin enhances the antitumor efficacy of anti-PD-1 therapy associated with tumor-infiltrating CD8+ T cell augmentation

PURPOSE

To investigate the antitumor efficacy of pingyangmycin (PYM) in combination with anti-PD-1 antibody and determine the capability of PYM to induce immunogenic cell death (ICD) in cancer cells.

METHODS

The murine 4T1 breast cancer and B16 melanoma models were used for evaluation of therapeutic efficacy of the combination of PYM with anti-PD-1 antibody. The ELISA kits were used to quantify the ICD related ATP and HMGB1 levels. The Transwell assay was conducted to determine the chemotaxis ability of THP-1 cell in vitro. The flow cytometry was used to measure reactive oxygen species level and analyze the ratio of immune cell subsets.

RESULTS

PYM induced ICD in murine 4T1 breast cancer and B16 melanoma cells and increased the release of nucleic acid fragments that may further promote the monocytic chemotaxis. In the 4T1 murine breast cancer model, PYM alone, anti-PD-1 antibody alone, and their combination suppressed tumor growth by 66.3%, 16.1% and 77.6%, respectively. PYM markedly enhanced the therapeutic efficacy of anti-PD-1 antibody against 4T1 breast cancer. The calculated CDI (coefficient of drug interaction) indicated synergistic effect. Evaluated by graphic analysis, the nucleated cells intensity in the femur bone marrow remained unchanged. Histopathological observations revealed no noticeable toxico-pathological changes in the lung and various organs, indicating that the PYM and anti-PD-1 antibody combination exerted enhanced efficacy at well-tolerated dosage level. By the combination treatment, a panel of immunological changes emerged. The ratio of CD3⁺ cells, NK cells and NKT cells increased and Tregs decreased in peripheral blood. The DCs increased in the spleen. Prominent changes occurred in tumor infiltrating lymphocytes. The ratio of CD8⁺ cells increased, while that of CD4⁺ cells decreased; however, the ratio of CD3⁺ cells remained unchanged, implying that certain immunological responses emerged in the tumor microenvironment. PYM alone could also increase CD8⁺ cells and reduce CD4⁺ cells in tumor infiltrating lymphocytes.

CONCLUSIONS

The studies indicate that PYM, as an ICD inducer with mild myelosuppression effect, may enhance the therapeutic efficacy of anti-PD-1 antibody in association with tumor infiltrating CD8⁺ T cell augmentation.