Copy number amplification of ENSA promotes the progression of triple-negative breast cancer via cholesterol biosynthesis

Tylophora yunnanensis extract inhibits cholesterol biosynthesis to suppress triple negative breast cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Female breast cancer ranks second in incidence rate and fourth in mortality globally. Tylophora yunnanensis Schlechter (Asclepiadaceae) is frequently used in folk medicine to treat irregular menses, falls caused injuries, rheumatoid arthritis, hepatitis, gastric ulcers, and gynecological tumors.

AIMS OF THE STUDY

To explore the molecular mechanism of T. yunnanensis against breast cancer.

MATERIALS AND METHODS

Numerous experiments were implemented for detection of cell proliferation, death, toxicity, MMP, cycle, apoptosis, DNA damage, and cholesterol levels. Transcriptomic analysis, proteomic analysis, exogenous cholesterol antagonism, gene overexpression and Western blot were performed to explore the mechanism of action. A tumor-bearing animal model was utilized. The chemical composition of T. yunnanensis extract (TYE) was analyzed using LC-MS/MS.

RESULTS

TYE repressed the proliferation of BT549 and 4T1 cells, with IC50 values of 4.88, 2.98 μg/mL for 24 h and 4.70, 1.87 μg/mL for 48 h, respectively. Cell cycle arrest was also induced. The multi-omics analysis displayed that TYE suppressed cholesterol biosynthesis and interfered with DNA damage repair in TNBC cells. Exogenous cholesterol reversed these effects, counteracted the elevated intracellular TC, FC, γ-H2AX, and tail moment. TYE downregulated the expression of SQLE, MVK, FDPS, TM7SF2, and DHCR24 proteins, which was offset by addition of cholesterol. Overexpression of SQLE reduced the inhibition effects of TYE on cell viability but was not responsible for the expression inhibition of MVK, FDPS and DHCR24 proteins. TYE decreased the tumor growth, serum TC and TG, and in situ expression of ki67 and SQLE in tumor-bearing mice and had no acute toxicity to mice. No chemical components of TYE were identified.

CONCLUSION

TYE inhibits SQLE transcription to decrease its protein expression, reduces cholesterol biosynthesis and accumulation, impedes DNA damage repair, leading to cell cycle arrest, and thus elicits cell death, followed by obstruction of breast cancer progression. T. yunnanensis may be a novel anti-breast cancer agent owing to its inhibitory effects on cholesterol biosynthesis.

Cholesterol metabolism: A strategy for overcoming drug resistance in tumors

Despite significant advancements in targeted tumor therapies, the emergence of drug resistance remains a complex challenge. Cholesterol accumulation within tumor cells plays a crucial role in mediating drug resistance through various mechanisms, including altered membrane dynamics, enhanced drug efflux, and activation of survival signaling pathways. Targeting cholesterol metabolism presents an innovative strategy to enhance therapeutic sensitivity, particularly in breast cancer. Consequently, ongoing preclinical studies and clinical trials involving cholesterol-lowering agents indicate a promising direction for improving treatment outcomes in tumors. The combination of these agents with existing therapeutic regimens may lead to enhanced efficacy, highlighting the necessity for continued research in this vital area. This review examines the impact of cholesterol metabolism on drug resistance in tumors, particularly solid tumors, identifies therapeutic targets in this metabolic pathway (with a special focus on breast cancer), and discusses recent advances in cholesterol-lowering drugs in preclinical, as well as those that have entered clinical trials.

Dysregulation of cholesterol homeostasis in cancer pathogenesis

Cholesterol is a unique lipid for all mammalian cells, with important functions in membrane biogenesis and maintenance of proper membrane integrity and fluidity. Therefore, it plays an important role in cellular homeostasis. Dysregulation of cholesterol homeostasis is associated with various diseases in humans, including cardiovascular diseases, inflammatory diseases, neurodegenerative disorders, and cancers. In the tumor microenvironment, intrinsic and extrinsic cellular factors reprogram cholesterol metabolism and consequently promote tumorigenesis. Here, we summarize the current knowledge on molecular mechanisms and functional roles of cholesterol homeostasis and its dysregulation in regard to cancer pathogenesis. We also discuss the interplay of cholesterol metabolism and the ATP-binding cassette (ABC) proteins, highly conserved cellular transmembrane lipid transporters. An emerging role of lipid ABC transporters as potential prognostic tools for cancer progression and invasiveness is emphasized. Targeting both cholesterol metabolism and proteins associated with membrane cholesterol holds promise as a novel therapeutic strategy for cancer treatment.

SREBP2 as a central player in cancer progression: potential for targeted therapeutics

Recent studies have identified the reprogramming of lipid metabolism as a critical hallmark of malignancy. Enhanced cholesterol uptake and increased cholesterol biosynthesis significantly contribute to the rapid growth of tumors, with cholesterol also playing essential roles in cellular signaling pathways. Targeting cholesterol metabolism has emerged as a promising therapeutic strategy in oncology. The sterol regulatory element-binding protein-2 (SREBP2) serves as a primary transcriptional regulator of genes involved in cholesterol biosynthesis and is crucial for maintaining cholesterol homeostasis. Numerous studies have reported the upregulation of SREBP2 across various cancers, facilitating tumor progression. This review aims to provide a comprehensive overview of the structure, biological functions, and regulatory mechanisms of SREBP2. Furthermore, we summarize that SREBP2 plays a crucial role in various cancers and tumor microenvironment primarily by regulating cholesterol, as well as through several non-cholesterol pathways. We also particularly emphasize therapeutic agents targeting SREBP2 that are currently under investigation. This review seeks to enhance our understanding of SREBP2's involvement in cancer and provide theoretical references for cancer therapies that target SREBP2.

Cholesterol metabolism in tumor immunity: Mechanisms and therapeutic opportunities for cancer

Cholesterol is an essential component of the cell membrane which plays a critical role in the survival of immune and tumor cells. Reprogramming of cholesterol metabolism in both tumor cells and immune cells can impact tumor progression and anti-tumor immune responses. Strategies aimed at modulating cholesterol metabolism have been demonstrated to be effective in hindering tumor growth and boosting anti-tumor immune functions. This review provides a thorough analysis of intracellular cholesterol homeostasis regulation in cells, focusing on key genes and signaling pathways. It particularly emphasizes the regulatory mechanisms and importance of the cholesterol presence state (esterified/free), levels of cholesterol, and its metabolites in immune and tumor cells. Additionally, the review thoroughly explores how cholesterol metabolism and sources (endogenous/exogenous) in the tumor microenvironment (TME) contribute to the interplay among tumor cells, immune suppressor cells, and immune effector cells, promoting cancer progression and immune evasion. It also delves into current insights on the influence of cholesterol metabolites and related drugs in regulating tumor development or immunotherapy. Finally, it presents an overview of recent advancements in clinical and preclinical trials investigating the efficacy of targeted cholesterol metabolism treatments and combination therapies in cancer management, while proposing potential future research directions in tumor immunity. This review is poised to offer fresh perspectives and avenues for examining the potential of cancer immunotherapy centered on cholesterol metabolism regulation.

Frequent copy number gain of MCL1 is a therapeutic target for osteosarcoma

Osteosarcoma (OS) is a primary malignant bone tumor primarily affecting children and adolescents. The lack of progress in drug development for OS is partly due to unidentified actionable oncogenic drivers common to OS. In this study, we demonstrate that copy number gains of MCL1 frequently occur in OS, leading to vulnerability to therapies based on Mcl-1 inhibitors. Fluorescence in situ hybridization analysis of 41 specimens revealed MCL1 amplification in 46.3% of patients with OS. Genetic inhibition of MCL1 induced significant apoptosis in MCL1-amplified OS cells, and the pharmacological efficacy of Mcl-1 inhibitors was correlated with MCL1 copy numbers. Chromosome 1q21.2-3 region, where MCL1 is located, contains multiple genes related to the IGF-1R/PI3K pathway, including PIP5K1A, TARS2, OUTD7B, and ENSA, which also showed increased copy numbers in MCL1-amplified OS cells. Furthermore, combining Mcl-1 inhibitors with IGF-1R inhibitors resulted in synergistic cell death by overcoming drug tolerance conferred by the activation of IGF signaling and suppressed tumor growth in MCL1-amplified OS xenograft models. These results suggest that genomic amplification of MCL1 in the 1q21.2-3 region, which occurred in approximately half of OS patients, may serve as a predictive biomarker for the combination therapy with an Mcl-1 inhibitor and an IGF1R inhibitor.

Targeting cholesterol metabolism: a promising therapy strategy for cancer

Cholesterol is a crucial structural component of cell membranes, playing a vital role in maintaining membrane fluidity and stability. Cholesterol metabolism involves four interconnected processes: de novo synthesis, uptake, efflux, and esterification. Disruptions in any of these pathways can lead to imbalances in cholesterol homeostasis, which are significantly associated with cancer progression. In recent years, traditional Chinese medicine (TCM) has emerged as a comprehensive therapeutic approach with multi-target and multi-pathway effects, demonstrating significant potential in regulating cholesterol metabolism. Research has shown that certain components of TCM can modulate enzymes, transport proteins, and signaling pathways involved in cholesterol metabolism, effectively interfering with survival and migration of cancer. These mechanisms highlight the unique advantages of TCM in inhibiting tumor progression. In this review we systematically describe the execution and regulation of the four key cholesterol metabolism processes, highlights the roles of critical proteins involved, and provides a comprehensive overview of natural products from TCM that modulate cholesterol metabolism. This review provides valuable insights for the development of novel drugs and cancer therapeutic strategies targeting cholesterol metabolism.

Biological effects of baicalin on the ovine mammary cells and regulatory mechanism study by transcriptomic analysis

Baicalin is a natural flavonoid compound with a wide range of biological activities, including anti-oxidant and anti-inflammatory properties. Previous we found that the abundance of baicalin in bovine serum is significantly higher than in ovine serum at mid-lactation. It suggests that baicalin may play a role in the regulation of lactation performance. Here, the biological effects of baicalin on proliferative, oxidative stress response, synthesis capacities of major milk components of ovine mammary epithelial cells (OMECs) were investigated. And the transcriptomic analysis was utilized to explore the possible regulatory mechanism. Results showed that 25 μg/mL baicalin can significantly enhance the proliferation, antioxidant, triglyceride and lactose synthesis capacities of OMECs. In transcriptomic analysis, 150 differentially expressed genes (DEGs) were screened between 25 μM baicalin treated (Baicalin) and 0 μM baicalin treated (NT) groups. Functional analysis of DEGs showed that lipid metabolic process, response to oxidative stress, biosynthesis of fat and saccharide pathways were enriched. qRT-PCR result showed that antioxidation-related negative regulatory gene MPO was significantly down-regulated and milk fat biosynthesis related genes PLA2G12A, GPCPD1, LPIN1, FASN and lactose biosynthesis related genes MGEA5, RHOQ were significantly up-regulated in baicalin treated OMECs (P < 0.01). In summarize, 25 μM baicalin can significantly enhance the proliferation, antioxidant and biosynthesis of milk fat and lactose capacities through lipid metabolic process, response to oxidative stress, biosynthesis of fat and saccharide pathways related genes regulation in OMECs. The study would provide a theoretical basis for the improvement of lactation performance and the exploration of lactation regulation theory of dairy sheep.

Dual Inhibition of CDK4/6 and CDK7 Suppresses Triple-Negative Breast Cancer Progression via Epigenetic Modulation of SREBP1-Regulated Cholesterol Metabolism

Inhibitors targeting cyclin-dependent kinases 4 and 6 (CDK4/6) to block cell cycle progression have been effective in treating hormone receptor-positive breast cancer, but triple-negative breast cancer (TNBC) remains largely resistant, limiting their clinical applicability. The study reveals that transcription regulator cyclin-dependent kinase7 (CDK7) is a promising target to circumvent TNBC's inherent resistance to CDK4/6 inhibitors. Combining CDK4/6 and CDK7 inhibitors significantly enhances therapeutic effectiveness, leading to a marked decrease in cholesterol biosynthesis within cells. This effect is achieved through reduced activity of the transcription factor forkhead box M1 (FOXM1), which normally increases cholesterol production by inducing SREBF1 expression. Furthermore, this dual inhibition strategy attenuates the recruitment of sterol regulatory element binding transcription factor 1 (SREBP1) and p300 to genes essential for cholesterol synthesis, thus hindering tumor growth. This research is corroborated by an in-house cohort showing lower survival rates in TNBC patients with higher cholesterol production gene activity. This suggests a new treatment approach for TNBC by simultaneously targeting CDK4/6 and CDK7, warranting additional clinical trials.

Tetramethylpyrazine attenuates the cancer stem cell like-properties and doxorubicin resistance by targeting HMGCR in breast cancer

BACKGROUND

Tetramethylpyrazine (TMP), a key bioactive constituent derived from Ligusticum wallichii Franchat, has demonstrated efficacy in mitigating multidrug resistance (MDR) in human breast cancer (BC) cells. However, the precise mechanisms underlying its action remain poorly understood.

PURPOSE

Cancer stem cells (CSCs) are widely recognized as the primary contributors to MDR. This investigation seeks to elucidate the role and mechanisms through which TMP counteracts MDR by attenuating CSC-like characteristics.

METHODS

Various assays, including flow cytometry, sphere formation, and Western blotting, were employed to evaluate TMP's effects on breast cancer stem cell (BCSC)-like phenotypes in vitro. In vivo, extreme limiting dilution assays and immunohistochemistry (IHC) were executed to assess the impacts of TMP on BCSC frequency and the levels of stemness markers. Mechanistically, RNA sequencing was performed to uncover the key biological processes involved in TMP's effects on BCSCs. Further experiments, encompassing micro scale thermophoresis (MST), drug affinity responsive target stability (DARTS), cellular thermal shift assay (CETSA) and amino acid mutation analyses, were utilized to identify the essential targets and corresponding binding sites of TMP. Finally, the effects of TMP on BCSC-like phenotypes were confirmed using cells with mutated amino acid residues, which allowed us to investigate the specificity of TMP's binding sites. To further evaluate the impact of TMP on drug resistance, doxorubicin-resistant MCF7 (MCF-7ADR) cells, along with corresponding cell lines harboring mutated amino acid residues, were employed.

RESULTS

TMP was found to inhibit BCSC-like properties both in vitro and in vivo, evidenced by a reduction in the CD44+/CD24- population, sphere formation capability, and expression of stemness markers. Mechanistic studies revealed that TMP targets 3‑hydroxy-3-methylglutaryl-CoA reductase (HMGCR), a rate-limiting enzyme in cholesterol biosynthesis. TMP binds to Asp-767 of HMGCR, thereby inhibiting its activity and reducing cholesterol synthesis. The influence of TMP on BCSC-like phenotypes was nullified by overexpression of wild-type HMGCR, while mutations in the binding site of HMGCR had no effect on TMP's inhibition of BCSC-like properties. Additionally, TMP mitigated MDR by targeting HMGCR.

CONCLUSION

These findings suggest that TMP alleviates MDR by reducing BCSC-like traits through targeting HMGCR and disruption of cholesterol biosynthesis in BC. This provides new insights into the mechanisms through which TMP alleviates MDR and offers new lead compound for exploring HMCGR antagonists.

Tumor-derived miR-9-5p-loaded EVs regulate cholesterol homeostasis to promote breast cancer liver metastasis in mice

Cancer cells secrete extracellular vesicles (EV) encapsulating bioactive cargoes to facilitate inter-organ communication in vivo and are emerging as critical mediators of tumor progression and metastasis, a condition which is often accompanied by a dysregulated cholesterol metabolism. Whether EVs are involved in the control of cholesterol homeostasis during tumor metastasis is still undefined and warrant further investigation. Here, we find that breast cancer-derived exosomal miR-9-5p induces the expression of HMGCR and CH25H, two enzymes involved in cholesterol synthesis and the conversion of 25-hydroxycholesterol from cholesterol by targeting INSIG1, INSIG2 and ATF3 genes in the liver. Notably, in vivo miR-9-5p antagomir treatment and genetic CH25H ablation prevents tumor metastasis in a mouse model of breast cancer. Thus, our findings reveal the regulatory mechanism of tumor-derived miR-9-5p in liver metastasis by linking oxysterol metabolism and Kupffer cell polarization, shedding light on future applications for cancer diagnosis and treatment.

Ketogenesis promotes triple-negative breast cancer metastasis via calpastatin β-hydroxybutyrylation

Triple-negative breast cancer (TNBC) continues to pose a significant obstacle in the field of oncology. Dysregulation of lipid metabolism, notably upregulated ketogenesis, has emerged as a hallmark of TNBC, yet its role in metastasis has been elusive. Here, by utilizing clinical specimens and experimental models, the study demonstrates that increased ketogenesis fosters TNBC metastasis by promoting the up-regulation of β-hydroxybutyrate (β-OHB), a key ketone body. Mechanistically, β-OHB facilitates β-hydroxybutyrylation (Kbhb) of Calpastatin (CAST), an endogenous calpain (CAPN) inhibitor, at K43, blocking the interaction with CAPN and subsequently promoting FAK phosphorylation and epithelial‒mesenchymal transition (EMT). In conclusion, the study reveals a novel regulatory axis linking ketogenesis to TNBC metastasis, shedding light on the intricate interplay between metabolic reprogramming and tumor progression.

m6A-Mediated Induction of 7-Dehydrocholesterol Reductase Stimulates Cholesterol Synthesis and cAMP Signaling to Promote Bladder Cancer Metastasis

Dysregulation of cholesterol homeostasis occurs in multiple types of tumors and promotes cancer progression. Investigating the specific processes that induce abnormal cholesterol metabolism could identify therapeutic targets to improve cancer treatment. In this investigation, we observed upregulation of 7-dehydrocholesterol reductase (DHCR7), a vital enzyme involved in the synthesis of cholesterol, within bladder cancer tissues in comparison to normal tissues, which was correlated with increased bladder cancer metastasis. Increased expression of DHCR7 in bladder cancer was attributed to decreased mRNA degradation mediated by YTHDF2. Loss or inhibition of DHCR7 reduced bladder cancer cell invasion in vitro and metastasis in vivo. Mechanistically, DHCR7 promoted bladder cancer metastasis by activating the cAMP/protein kinase A/FAK pathway. Specifically, DHCR7 increased cAMP levels by elevating cholesterol content in lipid rafts, thereby facilitating the transduction of signaling pathways mediated by cAMP receptors. DHCR7 additionally enhanced the cAMP signaling pathway by reducing the concentration of 7-dehydrocholesterol and promoting the transcription of the G protein-coupled receptor, namely gastric inhibitory polypeptide receptor. Overall, these findings demonstrate that DHCR7 plays an important role in bladder cancer invasion and metastasis by modulating cholesterol synthesis and cAMP signaling. Furthermore, inhibition of DHCR7 shows promise as a viable therapeutic strategy for suppressing bladder cancer invasion and metastasis. Significance: Inhibiting DHCR7 induces cholesterol metabolism reprogramming and lipid raft remodeling to inactivate the cAMP/protein kinase A/FAK axis and suppress bladder cancer metastasis, indicating the therapeutic potential of targeting DHCR7.

LIFR regulates cholesterol-driven bidirectional hepatocyte-neutrophil cross-talk to promote liver regeneration

Liver regeneration is under metabolic and immune regulation. Despite increasing recognition of the involvement of neutrophils in regeneration, it is unclear how the liver signals to the bone marrow to release neutrophils after injury and how reparative neutrophils signal to hepatocytes to reenter the cell cycle. Here we report that loss of the liver tumour suppressor Lifr in mouse hepatocytes impairs, whereas overexpression of leukaemia inhibitory factor receptor (LIFR) promotes liver repair and regeneration after partial hepatectomy or toxic injury. In response to physical or chemical damage to the liver, LIFR from hepatocytes promotes the secretion of cholesterol and CXCL1 in a STAT3-dependent manner, leading to the efflux of bone marrow neutrophils to the circulation and damaged liver. Cholesterol, via its receptor ERRα, stimulates neutrophils to secrete hepatocyte growth factor to accelerate hepatocyte proliferation. Altogether, our findings reveal a LIFR-STAT3-CXCL1-CXCR2 axis and a LIFR-STAT3-cholesterol-ERRα-hepatocyte growth factor axis that form bidirectional hepatocyte-neutrophil cross-talk to repair and regenerate the liver.

The HOXC10/NOD1/ERK axis drives osteolytic bone metastasis of pan-KRAS-mutant lung cancer

While KRAS mutation is the leading cause of low survival rates in lung cancer bone metastasis patients, effective treatments are still lacking. Here, we identified homeobox C10 (HOXC10) as a lynchpin in pan-KRAS-mutant lung cancer bone metastasis. Through RNA-seq approach and patient tissue studies, we demonstrated that HOXC10 expression was dramatically increased. Genetic depletion of HOXC10 preferentially impeded cell proliferation and migration in vitro. The bioluminescence imaging and micro-CT results demonstrated that inhibition of HOXC10 significantly reduced bone metastasis of KRAS-mutant lung cancer in vivo. Mechanistically, the transcription factor HOXC10 activated NOD1/ERK signaling pathway to reprogram epithelial-mesenchymal transition (EMT) and bone microenvironment by activating the NOD1 promoter. Strikingly, inhibition of HOXC10 in combination with STAT3 inhibitor was effective against KRAS-mutant lung cancer bone metastasis by triggering ferroptosis. Taken together, these findings reveal that HOXC10 effectively alleviates pan-KRAS-mutant lung cancer with bone metastasis in the NOD1/ERK axis-dependent manner, and support further development of an effective combinatorial strategy for this kind of disease.

Copy number alterations: a catastrophic orchestration of the breast cancer genome

Breast cancer (BCa) is a prevalent malignancy that predominantly affects women around the world. Somatic copy number alterations (CNAs) are tumor-specific amplifications or deletions of DNA segments that often drive BCa development and therapy resistance. Hence, the complex patterns of CNAs complement BCa classification systems. In addition, understanding the precise contributions of CNAs is essential for tailoring personalized treatment approaches. This review highlights how tumor evolution drives the acquisition of CNAs, which in turn shape the genomic landscapes of BCas. It also discusses advanced methodologies for identifying recurrent CNAs, studying CNAs in BCa and their clinical impact.

Using Copy Number Variation Data and Neural Networks to Predict Cancer Metastasis Origin Achieves High Area under the Curve Value with a Trade-Off in Precision

The accurate identification of the primary tumor origin in metastatic cancer cases is crucial for guiding treatment decisions and improving patient outcomes. Copy number alterations (CNAs) and copy number variation (CNV) have emerged as valuable genomic markers for predicting the origin of metastases. However, current models that predict cancer type based on CNV or CNA suffer from low AUC values. To address this challenge, we employed a cutting-edge neural network approach utilizing a dataset comprising CNA profiles from twenty different cancer types. We developed two workflows: the first evaluated the performance of two deep neural networks-one ReLU-based and the other a 2D convolutional network. In the second workflow, we stratified cancer types based on anatomical and physiological classifications, constructing shallow neural networks to differentiate between cancer types within the same cluster. Both approaches demonstrated high AUC values, with deep neural networks achieving a precision of 60%, suggesting a mathematical relationship between CNV type, location, and cancer type. Our findings highlight the potential of using CNA/CNV to aid pathologists in accurately identifying cancer origins with accessible clinical tests.

PKMYT1 knockdown inhibits cholesterol biosynthesis and promotes the drug sensitivity of triple-negative breast cancer cells to atorvastatin

Triple negative breast cancer (TNBC) as the most aggressive molecular subtype of breast cancer is characterized by high cancer cell proliferation and poor patient prognosis. Abnormal lipid metabolism contributes to the malignant process of cancers. Study observed significantly enhanced cholesterol biosynthesis in TNBC. However, the mechanisms underlying the abnormal increase of cholesterol biosynthesis in TNBC are still unclear. Hence, we identified a member of the serine/threonine protein kinase family PKMYT1 as a key driver of cholesterol synthesis in TNBC cells. Aberrantly high-expressed PKMYT1 in TNBC was indicative of unfavorable prognostic outcomes. In addition, PKMYT1 promoted sterol regulatory element-binding protein 2 (SREBP2)-mediated expression of enzymes related to cholesterol biosynthesis through activating the TNF/ TNF receptor-associated factor 1 (TRAF1)/AKT pathway. Notably, downregulation of PKMYT1 significantly inhibited the feedback upregulation of statin-mediated cholesterol biosynthesis, whereas knockdown of PKMYT1 promoted the drug sensitivity of atorvastatin in TNBC cells. Overall, our study revealed a novel function of PKMYT1 in TNBC cholesterol biosynthesis, providing a new target for targeting tumor metabolic reprogramming in the cancer.

Bone morphogenetic protein 4 derived from the cerebrospinal fluid in patients with postherpetic neuralgia induces allodynia via the crosstalk between microglia and astrocyte

INTRODUCTION

During postherpetic neuralgia (PHN), the cerebral spinal fluid (CSF) possesses the capability to trigger glial activation and inflammation, yet the specific changes in its composition remain unclear. Recent findings from our research indicate elevations of central bone morphogenetic protein 4 (BMP4) during neuropathic pain (NP), serving as an independent modulator of glial cells. Herein, the aim of the present study is to test the CSF-BMP4 expressions and its role in the glial modulation in the process of PHN.

METHODS

CSF samples were collected from both PHN patients and non-painful individuals (Control) to assess BMP4 and its antagonist Noggin levels. Besides, intrathecal administration of both CSF types was conducted in normal rats to evaluate the impact on pain behavior, glial activity, and inflammation.; Additionally, both Noggin and STAT3 antagonist-Stattic were employed to treat the PHN-CSF or exogenous BMP4 challenged cultured astrocytes to explore downstream signals. Finally, microglial depletion was performed prior to the PHN-CSF intervention so as to elucidate the microglia-astrocyte crosstalk.

RESULTS

BMP4 levels were significantly higher in PHN-CSF compared to Control-CSF (P < 0.001), with a positive correlation with pain duration (P < 0.05, r = 0.502). Comparing with the Control-CSF producing moderate paw withdrawal threshold (PWT) decline and microglial activation, PHN-CSF further exacerbated allodynia and triggered both microglial and astrocytic activation (P < 0.05). Moreover, PHN-CSF rather than Control-CSF evoked microglial proliferation and pro-inflammatory transformation, reinforced iron storage, and activated astrocytes possibly through both SMAD159 and STAT3 signaling, which were all mitigated by the Noggin application (P < 0.05). Next, both Noggin and Stattic effectively attenuated BMP4-induced GFAP and IL-6 upregulation, as well as SMAD159 and STAT3 phosphorylation in the cultured astrocytes (P < 0.05). Finally, microglial depletion diminished PHN-CSF induced astrogliosis, inflammation and endogenous BMP4 expression (P < 0.05).

CONCLUSION

Our study highlights the role of CSF-BMP4 elevation in glial activation and allodynia during PHN, suggesting a potential therapeutic avenue for future exploration.

Targeting STAT3 potentiates CDK4/6 inhibitors therapy in head and neck squamous cell carcinoma

Anti-CDK4/6 therapy has been employed for the treatment for head and neck squamous cell carcinoma (HNSCC) with CDK4/6 hyperactivation, but the response rate is relatively low. In this study, we first showed that CDK4 and CDK6 was over-expressed and conferred poor prognosis in HNSCC. Moreover, in RB-positive HNSCC, STAT3 signaling was activated induced by CDK4/6 inhibition and STAT3 promotes RB deficiency by upregulation of MYC. Thirdly, the combination of Stattic and CDK4/6 inhibitor results in striking anti-tumor effect in vitro and in Cal27 derived animal models. Additionally, phospho-STAT3 level negatively correlates with RB expression and predicts poor prognosis in patients with HNSCC. Taken together, our findings suggest an unrecognized function of STAT3 confers to CDK4/6 inhibitors resistance and presenting a promising combination strategy for patients with HNSCC.

Copy number gain of FAM131B-AS2 promotes the progression of glioblastoma by mitigating replication stress

BACKGROUND

Glioblastoma (GBM) is characterized by chromosome 7 copy number gains, notably 7q34, potentially contributing to therapeutic resistance, yet the underlying oncogenes have not been fully characterized. Pertinently, the significance of long noncoding RNAs (lncRNAs) in this context has gained attention, necessitating further exploration.

METHODS

FAM131B-AS2 was quantified in GBM samples and cells using qPCR. Overexpression and knockdown of FAM131B-AS2 in GBM cells were used to study its functions in vivo and in vitro. The mechanisms of FAM131B-AS2 were studied using RNA-seq, qPCR, Western blotting, RNA pull-down, coimmunoprecipitation assays, and mass spectrometry analysis. The phenotypic changes that resulted from FAM131B-AS2 variation were evaluated through CCK8 assay, EdU assay, comet assay, and immunofluorescence.

RESULTS

Our analysis of 149 primary GBM patients identified FAM131B-AS2, a lncRNA located in the 7q34 region, whose upregulation predicts poor survival. Mechanistically, FAM131B-AS2 is a crucial regulator of the replication stress response, stabilizing replication protein A1 through recruitment of ubiquitin-specific peptidase 7 and activating the ataxia telangiectasia and rad3-related protein kinase pathway to protect single-stranded DNA from breakage. Furthermore, FAM131B-AS2 overexpression inhibited CD8+ T-cell infiltration, while FAM131B-AS2 inhibition activated the cGAS-STING pathway, increasing lymphocyte infiltration and improving the response to immune checkpoint inhibitors.

CONCLUSIONS

FAM131B-AS2 emerges as a promising indicator for adjuvant therapy response and could also be a viable candidate for combined immunotherapies against GBMs.

Her-2/neu gene amplification and its correlation with other prognostic factors in Iranian breast cancer patients

BACKGROUND

Breast cancer is one of the most common diseases in females, arising from overexpression of a variety of oncogenes like HER2/neu. The amplification rate of this gene is variable in different breast cancer patients. In this study, the amplification of the HER2/neu oncogene was distinguished in breast cancer patients and its correlation with prognostic factors. Also, the simultaneous effect of prognostic factors on the occurrence of a specific prognostic factor was investigated.

MATERIALS AND METHODS

The multiplex PCR technique was used to assay the amplification of the HER2/neu oncogene in breast cancer patients. After extracting DNA from 100 tumor tissue and 8 normal breast tissue samples, the amplification of the HER2/neu gene was distinguished by the co-amplification of a single-copy reference gene, γ-IFN, and the target gene HER2/neu in the PCR reaction and using the Gel analyzer software. SPSS 23 and STATA 9.1 software were used for statistical analysis.

RESULTS

The HER2/neu gene was amplification in 30% of the tumor samples. The statistical analysis showed a statistically significant relationship between HER2/neu gene amplification and progesterone receptors. Amplification of the HER2/neu gene significantly increases the chance of lymph node involvement. Also, the amplification of this gene in tumors with histological grade II tissue is more than grade I.

CONCLUSION

The amplification of the HER2/neu gene can be used as an independent prognostic factor in predicting lymph node involvement and histological grade in breast cancer patients.

STAT3 activation of SCAP-SREBP-1 signaling upregulates fatty acid synthesis to promote tumor growth

SCAP plays a central role in controlling lipid homeostasis by activating SREBP-1, a master transcription factor in controlling fatty acid (FA) synthesis. However, how SCAP expression is regulated in human cancer cells remains unknown. Here, we revealed that STAT3 binds to the promoter of SCAP to activate its expression across multiple cancer cell types. Moreover, we identified that STAT3 also concurrently interacts with the promoter of SREBF1 gene (encoding SREBP-1), amplifying its expression. This dual action by STAT3 collaboratively heightens FA synthesis. Pharmacological inhibition of STAT3 significantly reduces the levels of unsaturated FAs and phospholipids bearing unsaturated FA chains by reducing the SCAP-SREBP-1 signaling axis and its downstream effector SCD1. Examination of clinical samples from patients with glioblastoma, the most lethal brain tumor, demonstrates a substantial co-expression of STAT3, SCAP, SREBP-1, and SCD1. These findings unveil STAT3 directly regulates the expression of SCAP and SREBP-1 to promote FA synthesis, ultimately fueling tumor progression.

Cholesterol metabolism in tumor microenvironment: cancer hallmarks and therapeutic opportunities

Cholesterol is crucial for cell survival and growth, and dysregulation of cholesterol homeostasis has been linked to the development of cancer. The tumor microenvironment (TME) facilitates tumor cell survival and growth, and crosstalk between cholesterol metabolism and the TME contributes to tumorigenesis and tumor progression. Targeting cholesterol metabolism has demonstrated significant antitumor effects in preclinical and clinical studies. In this review, we discuss the regulatory mechanisms of cholesterol homeostasis and the impact of its dysregulation on the hallmarks of cancer. We also describe how cholesterol metabolism reprograms the TME across seven specialized microenvironments. Furthermore, we discuss the potential of targeting cholesterol metabolism as a therapeutic strategy for tumors. This approach not only exerts antitumor effects in monotherapy and combination therapy but also mitigates the adverse effects associated with conventional tumor therapy. Finally, we outline the unresolved questions and suggest potential avenues for future investigations on cholesterol metabolism in relation to cancer.

Metabolism-regulating non-coding RNAs in breast cancer: roles, mechanisms and clinical applications

Breast cancer is one of the most common malignancies that pose a serious threat to women's health. Reprogramming of energy metabolism is a major feature of the malignant transformation of breast cancer. Compared to normal cells, tumor cells reprogram metabolic processes more efficiently, converting nutrient supplies into glucose, amino acid and lipid required for malignant proliferation and progression. Non-coding RNAs(ncRNAs) are a class of functional RNA molecules that are not translated into proteins but regulate the expression of target genes. NcRNAs have been demonstrated to be involved in various aspects of energy metabolism, including glycolysis, glutaminolysis, and fatty acid synthesis. This review focuses on the metabolic regulatory mechanisms and clinical applications of metabolism-regulating ncRNAs involved in breast cancer. We summarize the vital roles played by metabolism-regulating ncRNAs for endocrine therapy, targeted therapy, chemotherapy, immunotherapy, and radiotherapy resistance in breast cancer, as well as their potential as therapeutic targets and biomarkers. Difficulties and perspectives of current targeted metabolism and non-coding RNA therapeutic strategies are discussed.

Fluvastatin prevents lung metastasis in triple-negative breast cancer by triggering autophagy via the RhoB/PI3K/mTOR pathway

Triple-negative breast cancer is more common among younger than older women and is associated with the poorest survival outcomes of all breast cancer types. Fluvastatin inhibits tumour progression and induces the autophagy of breast cancer cells; however, the role of autophagy in fluvastatin-induced inhibition of breast cancer metastasis is unknown. Therefore, this study aimed to determine this mechanism. The effect of fluvastatin on human hormone receptor-negative breast cancer cells was evaluated in vitro via migration and wound healing assays, western blotting, and morphological measurements, as well as in vivo using a mouse xenograft model. Chloroquine, a prophylactic medication used to prevent malaria in humans was used as an autophagy inhibitor. We found that fluvastatin administration effectively prevented the migration/invasion of triple-negative breast cancer cells, an effect that was largely dependent on the induction of autophagy. Administration of the autophagy inhibitor chloroquine prevented the fluvastatin-induced suppression of lung metastasis in the nude mouse model. Furthermore, fluvastatin increased Ras homolog family member B (RhoB) expression, and the autophagy and anti-metastatic activity induced by fluvastatin were predominantly dependent on the regulation of RhoB through the protein kinase B-mammalian target of rapamycin (Akt-mTOR) signaling pathway. These results suggest that fluvastatin inhibits the metastasis of triple-negative breast cancer cells by modulating autophagy via the up regulation of RhoB through the AKT-mTOR signaling pathway. Fluvastatin may be a promising therapeutic option for patients with triple-negative breast cancer.

Multiomics of HER2-low triple-negative breast cancer identifies a receptor tyrosine kinase-relevant subgroup with therapeutic prospects

To provide complementary information and reveal the molecular characteristics and therapeutic insights of HER2-low breast cancer, we performed this multiomics study of hormone receptor-negative (HR-) and HER2-low breast cancer, also known as HER2-low triple-negative breast cancer (TNBC), and identified 3 subgroups: basal-like, receptor tyrosine kinase-relevant (TKR), and mesenchymal stem-like. These 3 subgroups had distinct features and potential therapeutic targets and were validated in external data sets. Interestingly, the TKR subgroup (which exists in both HR+ and HR- breast cancer) had activated HER2 and downstream MAPK signaling. In vitro and in vivo patient-derived xenograft experiments revealed that pretreatment of the TKR subgroup with a tyrosine kinase inhibitor (lapatinib or tucatinib) could inhibit HER2 signaling and induce accumulated expression of nonfunctional HER2, resulting in increased sensitivity to the sequential HER2-targeting, Ab-drug conjugate DS-8201. Our findings identify clinically relevant subgroups and provide potential therapeutic strategies for HER2-low TNBC subtypes.

KLHL29-mediated DDX3X degradation promotes chemosensitivity by abrogating cell cycle checkpoint in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a heterogeneous breast cancer subtype and accounts for approximately 15-20% of breast cancer cases. In this study, we identified KLHL29, which is an understudied member of the Kelch-like gene family, as a crucial tumor suppressor that regulates chemosensitivity in TNBC. KLHL29 expression was significantly downregulated in breast cancer tissues compared with adjacent normal tissues, and low levels of KLHL29 were associated with unfavorable prognoses. Ectopic KLHL29 suppressed, while depleting KLHL29 promoted, the growth, proliferation, migration, and invasion of TNBC. Mechanistically, KLHL29 recruited the CUL3 E3-ligase to the RNA-binding protein DDX3X, leading to the proteasomal degradation of the latter. This downregulation of DDX3X resulted in the destabilization of CCND1 mRNA and the consequent cell cycle arrest at G0/G1 phase. Remarkably, the DDX3X inhibitor RK33 combined with platinum-based chemotherapy can synergistically suppress TNBC that usually expresses low levels of KLHL29 and high levels of DDX3X using cancer cell-derived xenograft and patient-derived organoids models. Altogether, we uncovered the potential role for the KLHL29-DDX3X signaling cascade in the regulation of TNBC progression, thus providing a promising combination strategy for overcoming TNBC chemoresistance.

Gut microbial metabolite deoxycholic acid facilitates Th17 differentiation through modulating cholesterol biosynthesis and participates in high-fat diet-associated colonic inflammation

BACKGROUND

High-fat diet (HFD) is closely associated with the increased prevalence of inflammatory bowel disease (IBD). Excessive gut microbial metabolite deoxycholic acid (DCA) caused by HFD plays significant roles in eliciting intestinal inflammation, however, the mechanism underlining the induction of inflammatory response by DCA has not been fully elucidated. The purpose of this study was to investigate the role of DCA in the triggering of inflammation via affecting CD4+ T cell differentiation.

RESULTS

Murine CD4+T cells were cultured under Th1, Th2 or Th17-polarizing conditions treated with or without different dosage of DCA, and flowcytometry was conducted to detect the effect of DCA on CD4+ T cell differentiation. Alteration of gene expression in CD4+ T cells upon DCA treatment was determined by RNA-sequencing and qRT-PCR. Bioinformatic analysis, cholesterol metabolic profiling, ChIP assay and immuno-fluorescent staining were further applied to explore the DCA-regulated pathway that involved in CD4+T cell differentiation. The results showed that DCA could dose-dependently promote the differentiation of CD4+ T cell into Th17 linage with pathogenic signature. Mechanistically, DCA stimulated the expression of cholesterol biosynthetic enzymes CYP51 and led to the increased generation of endogenous RORγt agonists, including zymosterol and desmosterol, therefore facilitating Th17 differentiation. Up-regulation of CYP51 by DCA was largely mediated via targeting transcription factor SREBP2 and at least partially through bile acid receptor TGR5. In addition, DCA-supplemented diet significantly increased intestinal Th17 cell infiltration and exacerbated TNBS-induced colitis. Administration of cholestyramine to eliminate fecal bile acid obviously alleviated colonic inflammation accompanied by decreased Th17 cells in HFD-fed mice.

CONCLUSIONS

Our data establish a link between DCA-induced cholesterol biosynthesis in immune cells and gut inflammation. Modulation of bile acid level or targeting cholesterol metabolic pathway may be potential therapeutic measurements for HFD-related colitis.

Emerging therapies in cancer metabolism

Metabolic reprogramming in cancer is not only a biological hallmark but also reveals treatment vulnerabilities. Numerous metabolic molecules have shown promise as treatment targets to impede tumor progression in preclinical studies, with some advancing to clinical trials. However, the intricacy and adaptability of metabolic networks hinder the effectiveness of metabolic therapies. This review summarizes the metabolic targets for cancer treatment and provides an overview of the current status of clinical trials targeting cancer metabolism. Additionally, we decipher crucial factors that limit the efficacy of metabolism-based therapies and propose future directions. With advances in integrating multi-omics, single-cell, and spatial technologies, as well as the ability to track metabolic adaptation more precisely and dynamically, clinicians can personalize metabolic therapies for improved cancer treatment.

A phase II study of a doublet metronomic chemotherapy regimen consisting of oral vinorelbine and capecitabine in Chinese women with HER2-negative metastatic breast cancer

BACKGROUND

This single-arm prospective phase II trial was performed to assess the efficacy and safety of the dual oral metronomic vinorelbine and capecitabine (mNC) regimen in women with HER2-negative metastatic breast cancer (MBC) in China.

METHODS

The mNC regimen was administered to the enrolled cases, including oral vinorelbine (VNR) 40 mg three times weekly (on days 1, 3 and 5 every week) and capecitabine (CAP) 500 mg three times a day, until disease progression or intolerable toxicity. The primary endpoint was the 1-year progression-free survival (PFS) rate. Secondary endpoints included objective response rate (ORR), disease control rate (DCR), clinical benefit rate (CBR) and treatment-related adverse events (TRAEs). Stratified factors included treatment lines and hormone receptor (HR) status.

RESULTS

Between June 2018 and March 2023, 29 patients were enrolled into the study. The median follow-up time was 25.4 months (range, 2.0-53.8). In the entire group, the 1-year PFS rate was 54.1%. ORR, DCR and CBR were 31.0%, 96.6% and 62.1%, respectively. The mPFS was 12.5 months (range, 1.1-28.1). Subgroup analysis revealed that ORRs were 29.4% and 33.3% in first- and ≥second-line chemotherapy, respectively. ORRs were 29.2% (7/24) and 40.0% (2/5) for HR-positive MBC and metastatic triple-negative breast cancer (mTNBC), respectively. Grade 3/4 TRAEs were neutropenia (10.3%) and nausea/vomiting (6.9%).

CONCLUSIONS

The dual oral mNC regimen showed very good safety features and improved compliance without loss of efficacy in both first- and second-line treatments. The regimen also reached an excellent ORR in the mTNBC subgroup.

Integrating somatic CNV and gene expression in breast cancers from women with PTEN hamartoma tumor syndrome

Women with germline PTEN variants (PTEN hamartoma tumor syndrome, PHTS) have up to 85% lifetime risk of female breast cancer (BC). We previously showed that PHTS-derived BCs are distinct from sporadic BCs both at the clinical and genomic levels. In this study, we examined somatic copy number variations (CNV) and transcriptome data to further characterize the somatic landscape of PHTS-derived BCs. We analyzed exome sequencing data from 44 BCs from women with PHTS for CNV. The control group comprised of 558 women with sporadic BCs from The Cancer Genome Atlas (TCGA) dataset. Here, we found that PHTS-derived BCs have several distinct CNV peaks compared to TCGA. Furthermore, RNA sequencing data revealed that PHTS-derived BCs have a distinct immunologic cell type signature, which points toward cancer immune evasion. Transcriptomic data also revealed PHTS-derived BCs with pathogenic germline PTEN variants appear to have vitamin E degradation as a key pathway associated with tumorigenesis. In conclusion, our study revealed distinct CNV x transcript features in PHTS-derived BCs, which further facilitate understanding of BC biology arising in the setting of germline PTEN mutations.

Development and validation of an inflammatory response-related signature in triple negative breast cancer for predicting prognosis and immunotherapy

Background

Inflammation is one of the most important characteristics of tumor tissue. Signatures based on inflammatory response-related genes (IRGs) can predict prognosis and treatment response in a variety of tumors. However, the clear function of IRGs in the triple negative breast cancer (TNBC) still needs to be explored.

Methods

IRGs clusters were discovered via consensus clustering, and the prognostic differentially expressed genes (DEGs) across clusters were utilized to develop a signature using a least absolute shrinkage and selection operator (LASSO). Verification analyses were conducted to show the robustness of the signature. The expression of risk genes was identified by RT-qPCR. Lastly, we formulated a nomogram to improve the clinical efficacy of our predictive tool.

Results

The IRGs signature, comprised of four genes, was developed and was shown to be highly correlated with the prognoses of TNBC patients. In contrast with the performance of the other individual predictors, we discovered that the IRGs signature was remarkably superior. Also, the ImmuneScores were elevated in the low-risk group. The immune cell infiltration showed significant difference between the two groups, as did the expression of immune checkpoints.

Conclusion

The IRGs signature could act as a biomarker and provide a momentous reference for individual therapy of TNBC.

Cholesterol metabolism in cancer and cell death

SIGNIFICANCE

Cholesterol is a type of lipid that plays a crucial role in building and maintaining cell membranes, producing certain hormones, and aiding in digestion. The two main types of cholesterol are low-density lipoprotein and high-density lipoprotein, and maintaining a healthy balance between them is essential for cellular function and organism health.

RECENT ADVANCES

Cholesterol metabolism is a complex and dynamic process that involves biosynthesis, uptake, efflux, transport, and esterification. Disruptions in cholesterol metabolism are implicated in all stages of cancer, contributing to drug resistance, immune evasion, and autophagy dysfunction. These disruptions have also been linked to various types of regulated cell death, such as apoptosis, anoikis, lysosome-dependent cell death, pyroptosis, NETosis, necroptosis, entosis, ferroptosis, alkaliptosis, immunogenic cell death, and paraptosis.

CRITICAL ISSUES

Understanding the complex interplay between cholesterol metabolism and cell death and their impact on cancer development and progression is still a significant challenge. Additionally, there is currently a lack of reliable biomarkers that can accurately reflect cholesterol metabolism dysregulation in cancer.

FUTURE DIRECTIONS

To develop more specific and effective cholesterol metabolism-targeted therapies, a better understanding of the mechanisms by which cholesterol metabolism dysregulation contributes to cell death and cancer progression is needed. Additionally, improving the accuracy and reliability of biomarkers will be crucial for monitoring and diagnosing cholesterol-related cancer subtypes and evaluating the effectiveness of cholesterol metabolism-targeted therapies. These efforts will require ongoing research and collaboration among multidisciplinary teams of scientists and clinicians.

Cholesterol induces inflammation and reduces glucose utilization

Cholesterol stimulates inflammation and affects the normal function of islet tissues. However, the precise mechanism underlying the effects of cholesterol on islet cells requires clarification. In this study, we explored the role of cholesterol in glucose utilization in pancreatic cells. Beta-TC-6 cells and mice were treated with cholesterol. We used glucose detection kits to identify the glucose content in the cell culture supernatant and mouse serum and an enzyme-linked immunosorbent assay was used to detect insulin levels in the serum. Glucose-6-phosphatase catalytic subunit 2 (G6PC2), 78 kDa glucose-regulated protein (GRP78), 94 kDa glucose-regulated protein (GRP94), nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3), caspase-1 (casp1), and interleukin-1β (IL-1β) expression levels were detected using immunofluorescence, immunohistochemistry, western blotting, and reverse transcription-quantitative polymerase chain reaction. Hematoxylin-eosin staining was used to detect the histological alterations in pancreatic tissues. Cholesterol decreased beta-TC-6 cell glucose utilization; enhanced pancreatic tissue pathological alterations; increased glucose and insulin levels in mouse serum; increased G6PC2, GRP78, GRP94, and NLRP3 expression levels; and elevated casp1 and pro-IL-1β cleavage. Cholesterol can attenuate glucose utilization efficiency in beta-TC-6 cells and mice, which may be related to endoplasmic reticulum stress and inflammation.

Lactobacillus johnsonii alleviates colitis by TLR1/2-STAT3 mediated CD206+ macrophagesIL-10 activation

Imbalance of gut microbiota homeostasis is related to the occurrence of ulcerative colitis (UC), and probiotics are thought to modulate immune microenvironment and repair barrier function. Here, in order to reveal the interaction between UC and gut microbiota, we screened a new probiotic strain by 16S rRNA sequencing from Dextran Sulfate Sodium (DSS)-induced colitis mice, and explored the mechanism and clinical relevance. Lactobacillus johnsonii (L. johnsonii), as a potential anti-inflammatory bacterium was decreased colonization in colitis mice. Gavage L. johnsonii could alleviate colitis by specifically increasing the proportion of intestinal macrophages and the secretion of Il-10 with macrophages depleted model and in Il10^-/- mice. We identified this subset of immune cells activated by L. johnsonii as CD206⁺ macrophages^IL-10. Mechanistically, L. johnsonii supplementation enhanced the mobilization of CD206⁺ macrophages^IL-10 through the activation of STAT3 in vivo and in vitro. In addition, we revealed that TLR1/2 was essential for the activation of STAT3 and the recognition of L. johnsonii by macrophages. Clinically, there was positive correlation between the abundance of L. johnsonii and the expression level of MRC1, IL10 and TLR1/2 in UC tissues. L. johnsonii could activate native macrophages into CD206⁺ macrophages and release IL-10 through TLR1/2-STAT3 pathway to relieve experimental colitis. L. johnsonii may serve as an immunomodulator and anti-inflammatory therapeutic target for UC.

Comprehensive Analysis of the Immunogenomics of Triple-Negative Breast Cancer Brain Metastases From LCCC1419

Background

Triple negative breast cancer (TNBC) is an aggressive variant of breast cancer that lacks the expression of estrogen and progesterone receptors (ER and PR) and HER2. Nearly 50% of patients with advanced TNBC will develop brain metastases (BrM), commonly with progressive extracranial disease. Immunotherapy has shown promise in the treatment of advanced TNBC; however, the immune contexture of BrM remains largely unknown. We conducted a comprehensive analysis of TNBC BrM and matched primary tumors to characterize the genomic and immune landscape of TNBC BrM to inform the development of immunotherapy strategies in this aggressive disease.

Methods

Whole-exome sequencing (WES) and RNA sequencing were conducted on formalin-fixed, paraffin-embedded samples of BrM and primary tumors of patients with clinical TNBC (n = 25, n = 9 matched pairs) from the LCCC1419 biobank at UNC—Chapel Hill. Matched blood was analyzed by DNA sequencing as a comparison for tumor WES for the identification of somatic variants. A comprehensive genomics assessment, including mutational and copy number alteration analyses, neoantigen prediction, and transcriptomic analysis of the tumor immune microenvironment were performed.

Results

Primary and BrM tissues were confirmed as TNBC (23/25 primaries, 16/17 BrM) by immunohistochemistry and of the basal intrinsic subtype (13/15 primaries and 16/19 BrM) by PAM50. Compared to primary tumors, BrM demonstrated a higher tumor mutational burden. TP53 was the most frequently mutated gene and was altered in 50% of the samples. Neoantigen prediction showed elevated cancer testis antigen- and endogenous retrovirus-derived MHC class I-binding peptides in both primary tumors and BrM and predicted that single-nucleotide variant (SNV)-derived peptides were significantly higher in BrM. BrM demonstrated a reduced immune gene signature expression, although a signature associated with fibroblast-associated wound healing was elevated in BrM. Metrics of T and B cell receptor diversity were also reduced in BrM.

Conclusions

BrM harbored higher mutational burden and SNV-derived neoantigen expression along with reduced immune gene signature expression relative to primary TNBC. Immune signatures correlated with improved survival, including T cell signatures. Further research will expand these findings to other breast cancer subtypes in the same biobank. Exploration of immunomodulatory approaches including vaccine applications and immune checkpoint inhibition to enhance anti-tumor immunity in TNBC BrM is warranted.