Triple negative breast cancer: A thorough review of biomarkers

Mild Hyperthermia Enhanced Liposomal Doxorubicin Delivery and CD8+ T cell Infiltration in Triple Negative Breast Cancer

Mild hyperthermia (MHTh) is often used in combination with chemotherapy and radiotherapy for cancer treatment. In the current study, the effect of MHTh on the enhanced uptake of the FDA-approved chemotherapy drug, liposomal doxorubicin (dox) in syngeneic 4T1 tumors was investigated. Doxorubicin has inherent fluorescence properties having an emission signal at 590 nm upon excitation with a 480 nm laser. A group of mice administered with doxorubicin (dox) were exposed to MHTh (42 °C) for 30 minutes whereas control group given dox did not receive MHTh. Ex vivo optical imaging of harvested tumors confirmed higher uptake of dox in treated versus the control untreated tumors. Confocal microscopy of tumor sections indicates higher fluorescent intensity due to increased accumulation of dox in MHTh-treated compared to untreated tumors. We examined the effect of MHTh to enhance CD8 tumor infiltration, production of interferon-γ (IFN-γ) and expression of programmed death ligand-1 (PD-L1). mRNA in situ hybridization was performed to test for transcripts of CD8, IFN-γ and PD-L1. Results showed that higher expression of CD8 mRNA was observed in MHTh-administered tumors versus untreated cohorts. The signal for IFN-γ and PD-L1 in both groups were not significantly different. Taken together, our findings imply that MHTh can improve tumor uptake of dox. Importantly, our data suggests that MHTh can boost CD8+ T cell infiltration.

EPAC inhibitor suppresses angiogenesis and tumor growth of triple-negative breast cancer

AIMS

Exchange protein directly activated by cAMP 1 (EPAC1), a major isoform of guanine nucleotide exchange factors, is highly expressed in vascular endothelia cells and regulates angiogenesis in the retina. High intratumor microvascular densities (MVD) resulting from angiogenesis is responsible for breast cancer development. Downregulation of EPAC1 in tumor cell reduces triple-negative breast cancer (TNBC)-induced angiogenesis. However, whether Epac1 expressed in vascular endothelial cells contributes to angiogenesis and tumor development of TNBC remains elusive.

MAIN METHODS

We employed NY0123, a previously identified potent EPAC inhibitor, to explore the anti-angiogenic biological role of EPAC1 in vitro and in vivo through vascular endothelial cells, rat aortic ring, Matrigel plug, and chick embryo chorioallantoic membrane (CAM) and yolk sac membrane (YSM) assays, as well as the in vivo xenograft tumor models of TNBC in both chick embryo and mice.

KEY FINDINGS

Inhibiting EPAC1 in vascular endothelial cells by NY0123 significantly suppresses angiogenesis and tumor growth of TNBC. In addition, NY0123 possesses a better inhibitory efficacy than ESI-09, a reported specific EPAC inhibitor tool compound. Importantly, inhibiting EPAC1 in vascular endothelia cells regulates the typical angiogenic signaling network, which is associated with not only vascular endothelial growth factor (VEGF)/vascular endothelial growth factor receptor-2 (VEGFR2) signaling, but also PI3K/AKT, MEK/ERK and Notch pathway.

CONCLUSIONS

Our findings support that EPAC1 may serve as an effective anti-angiogenic therapeutic target of TNBC, and EPAC inhibitor NY0123 has the therapeutic potential to be developed for the treatment of TNBC.

Review of recent preclinical and clinical research on ligand-targeted liposomes as delivery systems in triple negative breast cancer therapy

Triple-negative breast Cancer (TNBC) is one of the deadliest types, making up about 20% of all breast cancers. Chemotherapy is the traditional manner of progressed TNBC treatment; however, it has a short-term result with a high reversibility pace. The lack of targeted treatment limited and person-dependent treatment options for those suffering from TNBC cautions to be the worst type of cancer among breast cancer patients. Consequently, appropriate treatment for this disease is considered a major clinical challenge. Therefore, various treatment methods have been developed to treat TNBC, among which chemotherapy is the most common and well-known approach recently studied. Although effective methods are chemotherapies, they are often accompanied by critical limitations, especially the lack of specific functionality. These methods lead to systematic toxicity and, ultimately, the expansion of multidrug-resistant (MDR) cancer cells. Therefore, finding novel and efficient techniques to enhance the targeting of TNBC treatment is an essential requirement. Liposomes have demonstrated that they are an effective method for drug delivery; however, among a large number of liposome-based drug delivery systems annually developed, a small number have just received authorization for clinical application. The new approaches to using liposomes target their structure with various ligands to increase therapeutic efficiency and diminish undesired side effects on various body tissues. The current study describes the most recent strategies and research associated with functionalizing the liposomes' structure with different ligands as targeted drug carriers in treating TNBCs in preclinical and clinical stages.

LncRNA MCM3AP-AS1 promotes chemoresistance in triple-negative breast cancer through the miR-524-5p/RBM39 axis

Triple-negative breast cancer (TNBC) is the most lethal subtype of BC, with unfavorable treatment outcomes. Evidence suggests the engagement of lncRNA MCM3AP-AS1 in BC development. This study investigated the action of MCM3AP-AS1 in chemoresistance of TNBC cells. Drug-resistant TNBC cell lines SUM159PTR and MDA-MB-231R were constructed by exposure to increasing concentrations of doxorubicin/docetaxel (DOX/DXL). MCM3AP-AS1 and miR-524-5p expression levels were determined by RT-qPCR. RNA binding motif 39 (RBM39) level was measured using Western blot. Cell viability and apoptosis were assessed by CCK-8 assay and flow cytometry. The targeted binding of miR-524-5p with MCM3AP-AS1 or RBM39 was predicted by ECORI database and validated by dual-luciferase assays. The gain-and-loss of function assays were conducted in cells to investigate the interactions among MCM3AP-AS1, miR-524-5p, and RBM39. TNBC xenograft mouse models were established through subcutaneous injection of MCM3AP-AS1-silencing MDA-MB-231R cells and intraperitoneally administrated with DOX/DXL to verify the role of MCM3AP-AS1 in vivo. MCM3AP-AS1 was upregulated in drug-resistant TNBC cells, and MCM3AP-AS1 silencing could sensitize drug-resistant TNBC cells to chemotherapeutic drugs by promoting apoptosis. MCM3AP-AS1 targeted miR-524-5p. After DOX/DXL treatment, miR-524-5p inhibition partially reversed the effect of MCM3AP-AS1 silencing on inhibiting chemoresistance and promoting apoptosis of drug-resistant TNBC cells. miR-524-5p targeted RBM39. Silencing MCM3AP-AS1 promoted apoptosis via the miR-524-5p/RBM39 axis, thereby enhancing chemosensitivity of drug-resistant TNBC cells. MCM3AP-AS1 knockdown upregulated miR-524-5p, downregulated RBM39, and restrained tumor development in vivo. MCM3AP-AS1 silencing potentiates apoptosis of drug-resistant TNBC cells by upregulating miR-524-5p and downregulating RBM39, thereby suppressing chemoresistance in TNBC.

Long non-coding RNA HANR modulates the glucose metabolism of triple negative breast cancer via stabilizing hexokinase 2

Increasing evidence has demonstrated the oncogenic roles of long non-coding RNA (lncRNA) hepatocellular carcinoma (HCC)-associated long non-coding RNA (HANR) in the development of HCC and lung cancer; however, the involvement of HANR in triple-negative breast cancer (TNBC) remains largely unknown. Our results demonstrated the significant overexpression of HANR in TNBC tissues and cells. Higher HANR levels significantly correlated with the poorer phenotypes in patients with TNBC. HANR down-regulation inhibited the proliferation and cell cycle progression and increased the apoptosis of TNBC cells. Mechanistically, immunoprecipitation-mass spectrometry revealed hexokinase II (HK2) as a direct binding target of HANR. HANR binds to and stabilizes HK2 through the proteasomal pathway. Consistent with the important role of HK2 in cancer cells, HANR depletion represses the glucose absorbance and lactate secretion, thus reprogramming the metabolism of TNBC cells. An in vivo xenograft model also demonstrated that HANR promoted tumor growth and aerobic glycolysis. This study reveals the role of HANR in modulating the glycolysis in TNBC cells by regulating HK2 stability, suggesting that HANR is a potential drug target for TNBC.

Pathologic and immunohistochemical prognostic markers in residual triple-negative breast cancer after neoadjuvant chemotherapy

Background

The persistence of residual tumour after neoadjuvant chemotherapy (NAC) in localised triple-negative breast cancer (TNBC) is known to have a negative prognostic value. However, different degrees of expression of some immunohistochemical markers may correlate with different prognoses.

Methods

The expression of biomarkers with a known prognostic value, i.e., cytokeratin 5/6 (CK5/6), androgen receptor (AR), epidermal growth factor receptor (EGFR) proliferation-related nuclear antigen Ki-67, human epidermal growth factor receptor 2 (HER2), protein 53 (p53), forkhead box protein 3 (FOXP3), and cluster differentiation 8 (CD8), was analysed by immunohistochemistry in 111 samples after NAC in non-metastatic TNBC patients addressed to Georges-François Leclerc Cancer Centre Dijon, France. Clinical and pathological variables were retrospectively collected. Cox regression was used to identify immunohistochemical (IHC) and clinicopathological predictors of event-free survival (EFS) (relapse or death).

Results

Median age was 50.4 years (range 25.6-88.3), 55.9% (n = 62) were non-menopausal, 70 (63.1%) had stage IIA-IIB disease. NAC was mostly sequential anthracycline-taxanes (72.1%), and surgical intervention was principally conservative (51.3%). We found 65.7% ypT1, 47.2% lymph node involvement (ypN+), and 29.4% lymphovascular invasion (LVI). Most residual tumours were EGFR >110 (H-score) (60.5%, n = 66), AR ≥4% (53.2%, n = 58), p53-positive mutated (52.7%, n = 58), CD8 ≥26 (58.1%, n = 61), FOXP3 ≥7 (51.4%, n = 54), more than half in the stroma, and 52.3% (n = 58) HER2 score 0. After a median follow-up of 80.8 months, 48.6% had relapsed. Median EFS was 62.3 months (95% CI, 37.2-not reached (NR)). Factors independently associated with poor EFS were AR-low (p = 0.002), ypN+ (p < 0.001), and LVI (p = 0.001). Factors associated with lower overall survival (OS) were EGFR-low (p = 0.041), Ki-67 high (p = 0.024), and ypN+ (p < 0.001).

Conclusion

Post-NAC residual disease in TNBC showed biomarkers specific to a basal-like subtype and markers of lymphocyte infiltration mostly present in the stroma. Prognostic markers for EFS were AR, LVI, and ypN and warrant further validation in a prognostic model.

Recent Advances of Multifunctional PLGA Nanocarriers in the Management of Triple-Negative Breast Cancer

Even though chemotherapy stands as a standard option in the therapy of TNBC, problems associated with it such as anemia, bone marrow suppression, immune suppression, toxic effects on healthy cells, and multi-drug resistance (MDR) can compromise their effects. Nanoparticles gained paramount importance in overcoming the limitations of conventional chemotherapy. Among the various options, nanotechnology has appeared as a promising path in preclinical and clinical studies for early diagnosis of primary tumors and metastases and destroying tumor cells. PLGA has been extensively studied amongst various materials used for the preparation of nanocarriers for anticancer drug delivery and adjuvant therapy because of their capability of higher encapsulation, easy surface functionalization, increased stability, protection of drugs from degradation versatility, biocompatibility, and biodegradability. Furthermore, this review also provides an overview of PLGA-based nanoparticles including hybrid nanoparticles such as the inorganic PLGA nanoparticles, lipid-coated PLGA nanoparticles, cell membrane-coated PLGA nanoparticles, hydrogels, exosomes, and nanofibers. The effects of all these systems in various in vitro and in vivo models of TNBC were explained thus pointing PLGA-based NPs as a strategy for the management of TNBC.

Predictive biomarkers of response and survival following immunotherapy with a PD-L1 inhibitor benmelstobart (TQB2450) and antiangiogenic therapy with a VEGFR inhibitor anlotinib for pretreated advanced triple negative breast cancer

In our phase Ib trial (ClinialTrials.gov Identifier: NCT03855358), benmelstobart (TQB2450), a novel humanized IgG1 antibody against PD-L1, plus antiangiogenic multikinase inhibitor, anlotinib, demonstrated promising antitumor activities in pretreated triple negative breast cancer (TNBC) patients. We conducted explorative analyses of genomic biomarkers to explore the associations with treatment response and survival outcomes. Targeted next generation sequencing (NGS) was undertaken toward circulating tumor DNA (ctDNA) collected from peripheral blood samples prior to the start of treatment and after disease progression. A total of 31 patients received targeted NGS and functional driver mutations in 29 patients were analyzed. The most frequent mutations were TP53 (72%), MLL3 (28%), and PIK3CA (17%). At a blood-based tumor mutational burden (bTMB) cutoff of 6.7 mutations per megabase, patients with low bTMB showed better response to anlotinib plus TQB2450 (50% vs. 7%, P = 0.015) and gained greater PFS benefits (7.3 vs. 4.1 months, P = 0.012) than those with high bTMB. At a maximum somatic allele frequency (MSAF) cutoff of 10%, a low MSAF indicated a better objective response (43% vs. 20%) as well as a significantly longer median PFS (7.9 vs. 2.7 months, P < 0.001). Patients with both low MSAF and low bTMB showed a notably better objective response to anlotinib plus TQB2450 (70% vs. 11%, P < 0.001) and a significantly longer median PFS (11.0 vs. 2.9 months, P < 0.001) than patients with other scenarios. Our findings support future studes and validation of MSAF and the combined bTMB-MSAF classification as predictive biomarkers of immune checkpoint inhibitor-based regimens in advanced TNBC patients.

Advances in Tumour-Infiltrating Lymphocytes for Triple-Negative Breast Cancer Management

Triple negative breast cancer (TNBC) is a subtype of breast cancer which does not express or expresses a minimum amount of estrogen receptors (ER), progesterone receptors (PR) and human epidermal growth factor receptor 2 (HER2) protein. TNBCs include a heterogenic group of cancers that are aggressive, grow rapidly and are associated with poor prognosis and overall survival, mainly attributed to a lack of effective therapeutic targets. For a long time, a major issue with predicting the outcome and prognosis of TNBCs was the lack of an accurate biomarker, a molecule that helps us objectively assess a patient's health status. In recent times, defining the presence of tumor-infiltrating lymphocytes (TIL) is becoming an indispensable method of determining a patient's prognosis. TILs are found in tumor tissue and the surrounding stroma and carry a prognostic value. Furthermore, they are known to improve the effect of systemic therapy. With the rise of immunotherapy, the role of TIL in this newer therapeutic option is a topic of increased importance. The goal behind this research article is a comprehensive review of the current literature on the importance of tumor-infiltrating lymphocytes in the prognosis of TNBC.

Zhuidu Formula suppresses the migratory and invasive properties of triple-negative breast cancer cells via dual signaling pathways of RhoA/ROCK and CDC42/MRCK

ETHNOPHARMACOLOGICAL RELEVANCE

Zhuidu Formula (ZDF) is composed of triptolide, cinobufagin and paclitaxel, which are the active ingredients of Tripterygium wilfordii Hook. F, dried toad skin and Taxus wallichiana var. chinensis (Pilg) Florin, respectively. Modern pharmacological studies show that triptolide, cinobufagin, and paclitaxel are well-known natural compounds that exert anti-tumor effects by interfering with DNA synthesis, inducing tumor cell apoptosis, and inhibiting the dynamic balance of the tubulin. However, the mechanism by which the three compounds inhibit triple-negative breast cancer (TNBC) metastasis is unknown.

OBJECTIVE

The objective of this investigation was to examine the inhibitory essences of ZDF on the metastasis of TNBC and elucidate its potential mechanism.

MATERIALS AND METHODS

Cell viability of triptolide (TPL), cinobufagin (CBF), and paclitaxel (PTX) on MDA-MB-231 cells was assessed employing a CCK-8 assay. The drug interactions of the three drugs on MDA-MB-231 cells were determined in vitro utilizing the Chou-Talalay method. MDA-MB-231 cells were identified for migration, invasion and adhesion in vitro through the implementation of the scratch assay, transwell assay and adhesion assay, respectively. The formation of cytoskeleton protein F-actin was detected by immunofluorescence assay. The expressions of MMP-2 and MMP-9 in the supernatant of the cells were determined by ELISA analysis. The Western blot and RT-qPCR were employed to explore the protein expressions associated with the dual signaling pathways of RhoA/ROCK and CDC42/MRCK. The anti-tumor efficacy of ZDF in vivo and its preliminary mechanism were investigated in the mouse 4T1 TNBC model.

RESULTS

The results demonstrated that ZDF could significantly reduce the viability of the MDA-MB-231 cell, and the combination index (CI) values of actual compatibility experimental points were all less than 1, demonstrating a favorable synergistic compatibility relationship. It was found that ZDF reduces RhoA/ROCK and CDC42/MRCK dual signaling pathways, which are responsible for MDA-MB-231cell migration, invasion, and adhesion. Additionally, there has been a significant reduction in the manifestation of cytoskeleton-related proteins. Furthermore, the expression levels of RhoA, CDC42, ROCK2, and MRCKβ mRNA and protein were down-regulated. ZDF significantly decreased the protein expressions of vimentin, cytokeratin-8, Arp2 and N-WASP, and inhibited actin polymerization and actomyosin contraction. Furthermore, MMP-2 and MMP-9 levels in the high-dose ZDF group were decreased by 30% and 26%, respectively. ZDF significantly reduced the tumor volume and protein expressions of ROCK2 and MRCKβ in tumor tissues without eliciting any perceptible alterations in the physical mass of the mice, and the reduction was more pronounced than that of the BDP5290 treated group.

CONCLUSION

The current investigation demonstrates that ZDF exhibits a proficient inhibitory impact on TNBC metastasis by regulating cytoskeletal proteins through the dual signaling pathways of RhoA/ROCK and CDC42/MRCK. Furthermore, the findings indicate that ZDF has significant anti-tumorigenic and anti-metastatic characteristics in breast cancer animal models.

A cascade nanoplatform for the regulation of the tumor microenvironment and combined cancer therapy

Recently, disulfiram (DSF), an anti-alcoholism drug, has attracted increasing biomedical interest due to its anticancer effects. However, the anticancer activity of DSF is Cu(II)-dependent and it is extremely unstable, which severely hinders its clinical translation. Herein, we report the fabrication of a multifunctional nanoplatform (MCDGF) that can improve the stability of diethyldithiocarbamate (DTC), a main metabolite of DSF, by modifying the aryl boronic ester group to form a prodrug (DQ), and also realize the in situ generation of Cu(DTC)2, which relies on a cascade reaction. The delivered Cu/DQ induces immunogenic cell death (ICD) and powerfully enhances immune responses of cytotoxic T lymphocytes (CTLs) and the infiltration of dendritic cells as well as T cells. Furthermore, the grafted glucose oxidase (GOx) decomposes glucose, thus "starving" the cancer cells and providing H2O2 for the production of Cu(DTC)2. More importantly, H2O2 significantly promotes the polarization of macrophages to the anti-tumor subtype. The nano-carrier "mesoporous polydopamine (MPDA)" also displays a good photothermal therapeutic effect. The nanoplatform-integrated chemotherapy, starvation therapy, photothermal therapy, and immunotherapy synergistically stimulated CTL activation and M1 macrophage polarization. Taken together, the as-prepared nanoplatform could regulate the tumor immune microenvironment and eliminate cancer with combined cancer therapy, which will offer a promising strategy for cancer treatment and promote the clinical application of DSF in breast cancer.

The PTX3/TLR4 autocrine loop as a novel therapeutic target in triple negative breast cancer

BACKGROUND

The pattern recognition receptor long pentraxin-3 (PTX3) plays conflicting roles in cancer by acting as an oncosuppressor or as a pro-tumor mediator depending on tumor context. Triple negative breast cancer (TNBC) represents the most aggressive histotype of breast cancer, characterized by the lack of efficacious therapeutic targets/approaches and poor prognosis. Thus, the characterization of new molecular pathways and/or alternative druggable targets is of great interest in TNBC.

METHODS

The expression of PTX3 in BC tumor samples and in BC cell lines has been analyzed using the Gene Expression-Based Outcome for Breast Cancer Online (GOBO), qPCR, Western blot and ELISA assay. The contribution of tumor and stromal cells to PTX3 production in TNBC was assessed by analyzing single cell RNA sequencing data and RNAscope performed on TNBC tumor samples. In order to investigate the effects of PTX3 in TNBC, different cell lines were engineered to knock-down (MDA-MB-231 and BT549 cells) or overexpress (MDA-MB-468 and E0771 cells) PTX3. Finally, using these engineered cells, in vitro (including gene expression profiling and gene set enrichment analyses) and in vivo (orthotopic tumor models in immune-compromised and immune competent mice) analyses were performed to assess the role and the molecular mechanism(s) exerted by PTX3 in TNBC.

RESULTS

In silico and experimental data indicate that PTX3 is mainly produced by tumor cells in TNBC and that its expression levels correlate with tumor stage. Accordingly, gene expression and in vitro results demonstrate that PTX3 overexpression confers a high aggressive/proliferative phenotype and fosters stem-like features in TNBC cells. Also, PTX3 expression induces a more tumorigenic potential when TNBC cells are grafted orthotopically in vivo. Conversely, PTX3 downregulation results in a less aggressive behavior of TNBC cells. Mechanistically, our data reveal that PTX3 drives the activation of the pro-tumorigenic Toll-like receptor 4 (TLR4) signaling pathway in TNBC, demonstrating for the first time that the PTX3/TLR4 autocrine stimulation loop contributes to TNBC aggressiveness and that TLR4 inhibition significantly impacts the growth of PTX3-producing TNBC cells.

CONCLUSION

Altogether, these data shed light on the role of tumor-produced PTX3 in TNBC and uncover the importance of the PTX3/TLR4 axis for therapeutic and prognostic exploitation in TNBC.

MEF2C and miR-194-5p: New Players in Triple Negative Breast Cancer Tumorigenesis

Among breast cancer (BC) subtypes, the most aggressive is triple negative BC (TNBC), which is prone to metastasis. We previously found that microRNA (miR)-194-5p is downregulated at the early stages of TNBC brain metastasis development. Additionally, the transcription factor myocyte enhancer factor 2 (MEF2)C, a bioinformatically predicted miR-194-5p target, was increasingly expressed throughout TNBC brain metastasis formation and disease severity. However, the contributions of these two players to malignant cells' features remain undetermined. This study aimed at disclosing the role of miR-194-5p and MEF2C in TNBC tumorigenesis. The transfection of 4T1 cells with a silencer for MEF2C or with a pre-miRNA for miR-194-5p was employed to study TNBC cells' phenotypic alterations regarding epithelial and mesenchymal markers, as well as migratory capability alterations. MEF2C-silenced cells presented a decline in both vimentin and cytokeratin expression, whereas the overexpression of miR-194-5p promoted an increase in cytokeratin and a reduction in vimentin, reflecting the acquisition of an epithelial phenotype. Both treatments reduced TNBC cells' migration. These results suggest that MEF2C may determine TNBC cells' invasive properties by partially determining the occurrence of epithelial-mesenchymal transition, while the overexpression of miR-194-5p promotes a decline in TNBC cells' aggressive behavior and reinforces this miRNA's role as a tumor suppressor in TNBC.

HER3 functions as an effective therapeutic target in triple negative breast cancer to potentiate the antitumor activity of gefitinib and paclitaxel

BACKGROUND

Triple negative breast cancer (TNBC) represents a significant clinical challenge. Chemotherapy remains the mainstay for a large part of TNBC patients, whereas drug resistance and tumor recurrence frequently occur. It is in urgent need to identify novel molecular targets for TNBC and develop effective therapy against the aggressive disease.

METHODS

Immunohistochemistry was performed to examine the expression of HER3 in TNBC samples. Western blots were used to assess protein expression and activation. Cell proliferation and viability were determined by cell growth (MTS) assays. TCGA databases were analyzed to correlate HER3 mRNA expression with the clinical outcomes of TNBC patients. Specific shRNA was used to knockdown HER3 expression. IncuCyte system was utilized to monitor cell growth and migration. LIVE/DEAD Cell Imaging was to detect live and dead cells. HER3 recognition by our anti-HER3 monoclonal antibody (mAb) 4A7 was verified by ELISA, flow cytometry, and co-immunoprecipitation assays. Orthotopic tumor models were established in nude mice to determine the capability of TNBC cells forming tumors and to test if our mAb 4A7 could potentiate the antitumor activity of paclitaxel in vivo.

RESULTS

Elevated expression of HER3 was observed in approximately half of the TNBC specimens and cell lines tested. Analyses of TCGA databases found that the TNBC patients with high HER3 mRNA expression in the tumors showed significantly worse overall survival (OS) and relapse-free survival (RFS) than those with low HER3 expression. Specific knockdown of HER3 markedly inhibited TNBC cell proliferation and mammosphere formation in vitro and tumor growth in vivo. Our mAb 4A7 abrogated heregulin (a ligand for HER3), but not SDF-1 (a ligand for CXCR4)-induced enhancement of TNBC cell migration. Combinations of 4A7 and the EGFR-tyrosine kinase inhibitor (TKI) gefitinib dramatically decreased the levels of phosphorylated HER3, EGFR, Akt, and ERK1/2 in TNBC cells and potently induced growth inhibition and cell death. Moreover, 4A7 in combination with paclitaxel exerted significant antitumor activity against TNBC in vitro and in vivo.

CONCLUSIONS

Our data demonstrate that increased HER3 is an effective therapeutic target for TNBC and our anti-HER3 mAb (4A7) may enhance the efficacy of gefitinib or paclitaxel in TNBC.

A meta-analysis of application of PD-1/PD-L1 inhibitor-based immunotherapy in unresectable locally advanced triple-negative breast cancer

Aims: The purpose of this study was to explore the efficacy of immunotherapy for patients with triple-negative breast cancer (TNBC). Materials & methods: Randomized clinical trials comparing immunotherapy with chemotherapy for advanced TNBC patients were included. Results: A total of six articles (3183 patients) were eligible for this meta-analysis. PD-1/PD-L1 inhibitor-based immunotherapy combined with chemotherapy can significantly increase the progression-free survival (hazard ratio [HR] = 0.82; 95% CI = 0.76-1.14; p < 0.001) of unresectable locally advanced or metastatic TNBC patients without effect on overall survival, compared with chemotherapy. Conclusion: PD-1/PD-L1 inhibitors-based immunotherapy can safely improve progression-free survival in patients with unresectable locally advanced or metastatic TNBC, but has no effect on overall survival.

Gold-Catalyzed Formal [4+2] Cycloaddition as Access to Antitumor-Active Spirocyclic Oxindoles from Alkynes and Isatin-Derived Ketimines

Due to its excellent bioactivity profile, which is increasingly utilized in pharmaceutical and synthetic chemistry, spirooxindole is an important core scaffold. We herein describe an efficient method for the construction of highly functionalized new spirooxindolocarbamates via a gold-catalyzed cycloaddition reaction of terminal alkynes or ynamides with isatin-derived ketimines. This protocol has a good functional group compatibility, uses readily available starting materials, mild reaction conditions, low catalyst loadings and no additives. It enables the transformation of various functionalized alkyne groups into cyclic carbamates. Gram-scale synthesis was achieved and DFT calculations verify the feasibility of the mechanistic proposal. Some of the target products exhibit good to excellent antiproliferative activity on human tumor cell lines. In addition, one of the most active compounds displayed a remarkable selectivity towards tumor cells over normal ones.

Small EV in plasma of triple negative breast cancer patients induce intrinsic apoptosis in activated T cells

Small extracellular vesicles (sEV) in TNBC patients' plasma promote T cell dysfunction and tumor progression. Here we show that tumor cell-derived exosomes (TEX) carrying surface PDL-1, PD-1, Fas, FasL, TRAIL, CTLA-4 and TGF-β1 induce apoptosis of CD8+T and CD4+T cells but spare B and NK cells. Inhibitors blocking TEX-induce receptor/ligand signals and TEX pretreatments with proteinase K or heat fail to prevent T cell apoptosis. Cytochalasin D, Dynosore or Pit Stop 2, partly inhibit TEX uptake but do not prevent T cell apoptosis. TEX entry into T cells induces cytochrome C and Smac release from mitochondria and caspase-3 and PARP cleavage in the cytosol. Expression of survival proteins is reduced in T cells undergoing apoptosis. Independently of external death receptor signaling, TEX entry into T cells induces mitochondrial stress, initiating relentless intrinsic apoptosis, which is responsible for death of activated T cells in the tumor-bearing hosts. The abundance of TEX in cancer plasma represents a danger for adoptively transferred T cells, limiting their therapeutic potential.

Matrix Metalloproteinase-9 Expression Is Associated with the Absence of Response to Neoadjuvant Chemotherapy in Triple-Negative Breast Cancer Patients

Triple-negative breast cancer (TNBC) is particularly challenging due to the weak or absent response to therapeutics and its poor prognosis. The effectiveness of neoadjuvant chemotherapy (NAC) response is strongly influenced by changes in elements of the tumor microenvironment (TME). This work aimed to characterize the residual TME composition in 96 TNBC patients using immunohistochemistry and in situ hybridization techniques and evaluate its prognostic implications for partial responders vs. non-responders. Compared with non-responders, partial responders containing higher levels of CD83+ mature dendritic cells, FOXP3+ regulatory T cells, and IL-15 expression but lower CD138+ cell concentration exhibited better OS and RFS. However, along with tumor diameter and positive nodal status at diagnosis, matrix metalloproteinase-9 (MMP-9) expression in the residual TME was identified as an independent factor associated with the impaired response to NAC. This study yields new insights into the key components of the residual tumor bed, such as MMP-9, which is strictly associated with the lack of a pathological response to NAC. This knowledge might help early identification of TNBC patients less likely to respond to NAC and allow the establishment of new therapeutic targets.

Exploring the Therapeutic Potential of trans-Chalcone: Modulation of MicroRNAs Linked to Breast Cancer Progression in MCF-7 Cells

Breast cancer is responsible for 25% of all cancers that affect women. Due to its high heterogeneity pattern in clinical diagnosis and its molecular profile differences, researchers have been seeking new targets and therapies, with more specificity and fewer side effects. Thus, one compound that has garnered our attention is trans-chalcone, which is naturally occurring in various plants and possesses promising biological properties, including antitumor effects. MiRNA is an extensive class of non-coding small, endogenous, and single-stranded RNAs, and it is involved in post-translational gene regulation. Therefore, the objective of this study was to investigate the effects of TChal on miRNAs expression and its relationship with anticancer activity against MCF-7. Initially, the trans-chalcone IC50 value was established by MTT assay for MCF-7and HaCat (non-cancer cell), in which we found out that it was 53.73 and 44.18 μM, respectively. Subsequently, we treated MCF-7 cells with trans-chalcone at its IC50 concentration and performed Mi-seq analysis, which unveiled 23 differentially expressed miRNAs. From this set, we selected five miRNAs (miR-25-5p, miR-27a-3p, miR-891a, miR-449a, and miR-4485) for further validation using qRT-PCR, guided by in silico analysis and their known association with tumorigenesis. In conclusion, our research provides valuable insights into the potential use of TChal to reveal MicroRNAs molecular targets that can be applied in breast cancer therapy.

Triple Negative Breast Cancer Treatment Options and Limitations: Future Outlook

Triple negative breast cancer (TNBC) has a negative expression of estrogen receptors (ER), progesterone receptors (PR), and human epidermal growth factor receptors (HER2). The survival rate for TNBC is generally worse than other breast cancer subtypes. TNBC treatment has made significant advances, but certain limitations remain. Treatment for TNBC can be challenging since the disease has various molecular subtypes. A variety of treatment options are available, such as chemotherapy, immunotherapy, radiotherapy, and surgery. Chemotherapy is the most common of these options. TNBC is generally treated with systemic chemotherapy using drugs such as anthracyclines and taxanes in neoadjuvant or adjuvant settings. Developing resistance to anticancer drugs and off-target toxicity are the primary hindrances to chemotherapeutic solutions for cancer. It is imperative that researchers, clinicians, and pharmaceutical companies work together to develop effective treatment options for TNBC. Several studies have suggested nanotechnology as a potential solution to the problem of suboptimal TNBC treatment. In this review, we summarized possible treatment options for TNBC, including chemotherapy, immunotherapy, targeted therapy, combination therapy, and nanoparticle-based therapy, and some solutions for the treatment of TNBC in the future. Moreover, we gave general information about TNBC in terms of its characteristics and aggressiveness.

DNA hydrogels and nanogels for diagnostics, therapeutics, and theragnostics of various cancers

As an efficient class of hydrogel-based therapeutic drug delivery systems, deoxyribonucleic acid (DNA) hydrogels (particularly DNA nanogels) have attracted massive attention in the last five years. The main contributor to this is the programmability of these 3-dimensional (3D) scaffolds that creates fundamental effects, especially in treating cancer diseases. Like other active biological ingredients (ABIs), DNA hydrogels can be functionalized with other active agents that play a role in targeting drug delivery and modifying the half-life of the therapeutic cargoes in the body's internal environment. Considering the brilliant advantages of DNA hydrogels, in this survey, we intend to submit an informative collection of feasible methods for the design and preparation of DNA hydrogels and nanogels, and the responsivity of the immune system to these therapeutic cargoes. Moreover, the interactions of DNA hydrogels with cancer biomarkers are discussed in this account. Theragnostic DNA nanogels as an advanced species for both detection and therapeutic purposes are also briefly reviewed.

Nigericin Boosts Anti-Tumor Immune Response via Inducing Pyroptosis in Triple-Negative Breast Cancer

Although immune checkpoint inhibitors improved the clinical outcomes of advanced triple negative breast cancer (TBNC) patients, the response rate remains relatively low. Nigericin is an antibiotic derived from Streptomyces hydrophobicus. We found that nigericin caused cell death in TNBC cell lines MDA-MB-231 and 4T1 by inducing concurrent pyroptosis and apoptosis. As nigericin facilitated cellular potassium efflux, we discovered that it caused mitochondrial dysfunction, leading to mitochondrial ROS production, as well as activation of Caspase-1/GSDMD-mediated pyroptosis and Caspase-3-mediated apoptosis in TNBC cells. Notably, nigericin-induced pyroptosis could amplify the anti-tumor immune response by enhancing the infiltration and anti-tumor effect of CD4+ and CD8+ T cells. Moreover, nigericin showed a synergistic therapeutic effect when combined with anti-PD-1 antibody in TNBC treatment. Our study reveals that nigericin may be a promising anti-tumor agent, especially in combination with immune checkpoint inhibitors for advanced TNBC treatment.

Therapeutic effects of guanidine hydrochloride on breast cancer through targeting KCNG1 gene

BACKGROUND

Triple-negative breast cancer (TNBC) is one of the subtypes of breast cancer (BC) that is associated with poor survival rates and failure to respond to hormonal and targeted therapies.

OBJECTIVE

The aim of this study was to identify a specific gene at the expression level for TNBC and targeting of this type of breast cancer based on it. Using TCGA database, genes that are particularly high expression in TNBC subtypes compared to other BC subtypes (in terms of receptor status) and normal samples were identified and their sensitivity and specificity were evaluated. Using PharmacoGX and Drug Bank data, drug sensitivity and drug-appropriate genes were identified, respectively. The effects of the identified drug on triple-negative cell lines (MDA-MB-468) were evaluated in comparison with the cell line of other subtypes (MCF7) by apoptosis and MTS tests.

RESULTS

Data analyzes showed that the expression level of KCNG1 gene in the TNBC subgroup was significantly higher compared to other BC subtypes from the KCN gene family and ROC results showed that this gene had highest sensitivity and specificity in TNBC subtype. The results of drug resistance and sensitivity showed that an increase in the expression level of KCNG1 was associated with sensitivity to Cisplatin and Oxaliplatin. Moreover, Drug Bank results showed that Guanidine hydrochloride (GuHCl) was a suitable inhibitor for KCNG1. In vitro results showed that the expression level of KCNG1 was higher in MDA-MB-468 compared to MCF7. In addition, the rate of apoptosis in response to GuHCl treatment in MDA-MB-468 cell line as TNBC cell model was higher than MCF7 in the same concentration.

CONCLUSION

This study revealed that GuHCl could be a suitable treatment for TNBC subtype by targeting of KCNG1.

circ-0000512 inhibits PD-L1 ubiquitination through sponging miR-622/CMTM6 axis to promote triple-negative breast cancer and immune escape

BACKGROUND

This study reported the function and mechanism of circ-0000512 in the progression of triple-negative breast cancer (TNBC).

METHODS

circ-0000512 expression in TNBC tissues and paired adjacent normal tissues and cells was examined by qRT-PCR. Moreover, circ-0000512 expression in TNBC cells was modulated by transfection. Thereafter, colony formation assay, Transwell assay and flow cytometry were conducted to observe cell proliferation, migration and apoptosis. TNBC cells were treated with cycloheximide and the protease inhibitor MG132. Later, ubiquitination assay was performed to detect programmed cell death ligand 1 (PD-L1) ubiquitination in TNBC cells. The T cell killing ability was assessed by the T cell-mediated tumor cell killing assay. IFNγ and IL-2 levels were detected by ELISA. The percentage of activated T cells was detected with a flow cytometer. In addition, dual luciferase reporter gene assay and RNA immunoprecipitation assay were carried out to evaluate the binding between two genes. In vivo study was conducted on mice. CD8+ T cells in xenograft tumors were detected by immunohistochemistry.

RESULTS

circ-0000512 was upregulated in patients with TNBC. circ-0000512 knockdown attenuated the proliferation and migration of TNBC cells and enhanced their apoptosis. circ-0000512 overexpression had opposite effects. circ-0000512 knockdown enhanced the PD-L1 protein ubiquitination in TNBC cells by inhibiting CMTM6. Meanwhile, circ-0000512 promoted CMTM6 expression by sponging miR-622. circ-0000512 knockdown increased the ratio of CD8+T cells and the lethality of T cells against TNBC cells. Besides, circ-0000512 knockdown inhibited the growth of TNBC cells in immunodeficient nude mice and normal immune mice and increased the ratio of CD8+T cells in xenograft tumors of normal immune mice.

CONCLUSIONS

circ-0000512 inhibited PD-L1 ubiquitination by sponging the miR-622/CMTM6 axis, thus promoting TNBC progression and immune escape.

Effect of surgical treatment on patients with stage T3 or T4 triple-negative breast cancer: a SEER-based retrospective observational study

Background

The use of surgery is controversial in patients with stage T3 or T4 triple-negative breast cancer (TNBC). We aimed to explore the effect of surgical treatment on overall survival (OS) of these patients.

Methods

A total of 2,041 patients were selected and divided into the surgical and non-surgical groups based on the Surveillance, Epidemiology, and End Results database from 2010 to 2018. Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were applied to balance covariates between different groups. The OS of the two groups were assessed by Kaplan-Meier survival curves and Cox proportional hazards regression models.

Results

A total of 2,041 patients were included in the study. After PSM and IPTW, baseline characteristics of the matched variables were fully balanced. Kaplan-Meier survival curves showed that the median survival time and OS of TNBC patients with stage T3 or T4 in the surgical group were significantly improved compared with those in the non-surgical group. Multivariate Cox proportional hazards regression analysis showed that surgery was a protective factor for prognosis.

Conclusion

Our study found that surgery prolonged the median survival and improved OS compared with the non-surgical group of TNBC patients with stage T3 or T4.

Endorsement of TNBC Biomarkers in Precision Therapy by Nanotechnology

Breast cancer is a heterogeneous disease which accounts globally for approximately 1 million new cases annually, wherein more than 200,000 of these cases turn out to be cases of triple-negative breast cancer (TNBC). TNBC is an aggressive and rare breast cancer subtype that accounts for 10-15% of all breast cancer cases. Chemotherapy remains the only therapy regimen against TNBC. However, the emergence of innate or acquired chemoresistance has hindered the chemotherapy used to treat TNBC. The data obtained from molecular technologies have recognized TNBC with various gene profiling and mutation settings that have helped establish and develop targeted therapies. New therapeutic strategies based on the targeted delivery of therapeutics have relied on the application of biomarkers derived from the molecular profiling of TNBC patients. Several biomarkers have been found that are targets for the precision therapy in TNBC, such as EGFR, VGFR, TP53, interleukins, insulin-like growth factor binding proteins, c-MET, androgen receptor, BRCA1, glucocorticoid, PTEN, ALDH1, etc. This review discusses the various candidate biomarkers identified in the treatment of TNBC along with the evidence supporting their use. It was established that nanoparticles had been considered a multifunctional system for delivering therapeutics to target sites with increased precision. Here, we also discuss the role of biomarkers in nanotechnology translation in TNBC therapy and management.

Effect of Melittin Complexes with Graphene and Graphene Oxide on Triple-Negative Breast Cancer Tumors Grown on Chicken Embryo Chorioallantoic Membrane

One of the components of bee venom is melittin (M), which has strong lysing properties on membranes. M has high toxicity to cancer cells, but it also affects healthy cells, making it necessary to use methods for targeted delivery to ensure treatment. This research is a continuation of previous studies using graphene nanomaterials as M carriers to breast cancer cells. The studies described below are conducted on a more organized biological structure than what is found in vitro cells, namely, cancerous tumors grown on a chicken embryo chorioallantoic membrane. Caspase 3 and 8 levels are analyzed, and the level of oxidative stress markers and changes in protein expression for cytokines are examined. The results show that M complexes with nanomaterials reduce the level of oxidative stress more than M alone does, but the use of graphene (GN) as a carrier increases the level of DNA damage to a greater extent than the increase caused by M alone. An analysis of cytokine levels shows that the use of the M and GN complex increases the level of proteins responsible for inhibiting tumor progression to a greater extent than the increase occasioned by a complex with graphene oxide (GO). The results suggest that the use of GN as an M carrier may increase the toxic effect of M on structures located inside a cell.

Antiproliferative Effect of Inorganic and Organic Selenium Compounds in Breast Cell Lines

Triple-negative breast cancer (TNBC) is an aggressive, fast-growing tumor that is more likely to spread to distant organs. Among women diagnosed with breast cancer, the prevalence of TNBC is 20%, and treatment is currently limited to chemotherapy. Selenium (Se), an essential micronutrient, has been explored as an antiproliferative agent. Therefore, this study aimed to evaluate the effects of exposure to organic (selenomethionine, ebselen, and diphenyl diselenide) and inorganic (sodium selenate and sodium selenite) Se molecules in different breast cell lines. The compounds were tested at 1, 10, 50, and 100 μM for 48 h in the non-tumor breast cell line (MCF-10A) and TNBC derivatives cell lines (BT-549 and MDA-MB-231). The effects of Se on cell viability, apoptotic and necrotic processes, colony formation, and cell migration were analyzed. Exposure to selenomethionine and selenate did not alter the evaluated parameters. However, selenomethionine had the highest selectivity index (SI). The exposure to the highest doses of selenite, ebselen, and diphenyl diselenide resulted in antiproliferative and antimetastatic effects. Selenite had a high SI to the BT cell line; however, the SI of ebselen and diphenyl diselenide was low in both tumoral cell lines. In conclusion, the Se compounds had different effects on the breast cell lines, and additional tests are needed to reveal the antiproliferative effects of Se compounds.

TMEM25 inhibits monomeric EGFR-mediated STAT3 activation in basal state to suppress triple-negative breast cancer progression

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with poor outcome and lacks of approved targeted therapy. Overexpression of epidermal growth factor receptor (EGFR) is found in more than 50% TNBC and is suggested as a driving force in progression of TNBC; however, targeting EGFR using antibodies to prevent its dimerization and activation shows no significant benefits for TNBC patients. Here we report that EGFR monomer may activate signal transducer activator of transcription-3 (STAT3) in the absence of transmembrane protein TMEM25, whose expression is frequently decreased in human TNBC. Deficiency of TMEM25 allows EGFR monomer to phosphorylate STAT3 independent of ligand binding, and thus enhances basal STAT3 activation to promote TNBC progression in female mice. Moreover, supplying TMEM25 by adeno-associated virus strongly suppresses STAT3 activation and TNBC progression. Hence, our study reveals a role of monomeric-EGFR/STAT3 signaling pathway in TNBC progression and points out a potential targeted therapy for TNBC.

Convolutional neural network for biomarker discovery for triple negative breast cancer with RNA sequencing data

Triple negative breast cancers (TNBCs) are tumors with a poor treatment response and prognosis. In this study, we propose a new approach, candidate extraction from convolutional neural network (CNN) elements (CECE), for discovery of biomarkers for TNBCs. We used the GSE96058 and GSE81538 datasets to build a CNN model to classify TNBCs and non-TNBCs and used the model to make TNBC predictions for two additional datasets, the cancer genome atlas (TCGA) breast cancer RNA sequencing data and the data from Fudan University Shanghai Cancer Center (FUSCC). Using correctly predicted TNBCs from the GSE96058 and TCGA datasets, we calculated saliency maps for these subjects and extracted the genes that the CNN model used to separate TNBCs from non-TNBCs. Among the TNBC signature patterns that the CNN models learned from the training data, we found a set of 21 genes that can classify TNBCs into two major classes, or CECE subtypes, with distinct overall survival rates (P = 0.0074). We replicated this subtype classification in the FUSCC dataset using the same 21 genes, and the two subtypes had similar differential overall survival rates (P = 0.0490). When all TNBCs were combined from the 3 datasets, the CECE II subtype had a hazard ratio of 1.94 (95% CI, 1.25-3.01; P = 0.0032). The results demonstrate that the spatial patterns learned by the CNN models can be utilized to discover interacting biomarkers otherwise unlikely to be identified by traditional approaches.

Amide proton transfer (APT) imaging of breast cancers and its correlation with biological status

PURPOSE

To assess the usefulness of amide proton transfer (APT) imaging to predict the biological status of breast cancers.

METHOD

Sixty-six patients (age range 31-85 years, mean 58.9 years) with histopathologically proven invasive ductal carcinomas of 2 cm or larger in diameter were included in this study. 3D APT weighted imaging was conducted on a 3 T scanner. Mean APT signal intensity (SI) was analyzed in relation to biological subtypes, Ki-67 labeling index, and nuclear grades (NGs).

RESULTS

The triple-negative (TN) cancers (n = 10; 2.75 ± 0.42%) showed significantly higher APT SI than the luminal type cancers (n = 48; 1.74 ± 0.83) and HER2 cancers (n = 8; 1.83 ± 0.21) (P = 0.0007, 0.03). APT SI had weakly positive correlation with the Ki-67 labeling index (r = 0.38, P = 0.002). The mean APT SIs were significantly higher for high-Ki-67 (>30%) (n = 31; 2.25 ± 0.70) than low-Ki-67 (≤30%) cancers (n = 35; 1.60 ± 0.79) (P = 0.0007). There was no significant difference in the APT SIs between NG 1-2 (n = 31; 1.71 ± 0.84) and NG 3 (n = 35; 2.08 ± 0.76%) cancers (P = 0.06).

CONCLUSIONS

TN and high-Ki-67 breast cancers showed high APT SIs. APT imaging can help to predict the biological status of breast cancers.

Signals transduced by Eph receptors and ephrin ligands converge on MAP kinase and AKT pathways in human cancers

Eph receptors, the largest known family of receptor tyrosine kinases, and ephrin ligands have been implicated in a variety of human cancers. The novel bidirectional signaling events initiated by binding of Eph receptors to their cognate ephrin ligands modulate many cellular processes such as proliferation, metastasis, angiogenesis, invasion, and apoptosis. The relationships between the abundance of a unique subset of Eph receptors and ephrin ligands with associated cellular processes indicate a key role of these molecules in tumorigenesis. The combinatorial expression of these molecules converges on MAP kinase and/or AKT/mTOR signaling pathways. The intracellular target proteins of the initial signal may, however, vary in some cancers. Furthermore, we have also described the commonality of up- and down-regulation of individual receptors and ligands in various cancers. The current state of research in Eph receptors illustrates MAP kinase and mTOR pathways as plausible targets for therapeutic interventions in various cancers.

Targeting KK-LC-1 inhibits malignant biological behaviors of triple-negative breast cancer

BACKGROUND

Cancer/testis antigens (CTAs) participate in the regulation of malignant biological behaviors in breast cancer. However, the function and mechanism of KK-LC-1, a member of the CTA family, in breast cancer are still unclear.

METHODS

Bioinformatic tools, immunohistochemistry, and western blotting were utilized to detect the expression of KK-LC-1 in breast cancer and to explore the prognostic effect of KK-LC-1 expression in breast cancer patients. Cell function assays, animal assays, and next-generation sequencing were utilized to explore the function and mechanism of KK-LC-1 in the malignant biological behaviors of triple-negative breast cancer. Small molecular compounds targeting KK-LC-1 were also screened and drug susceptibility testing was performed.

RESULTS

KK-LC-1 was significantly highly expressed in triple-negative breast cancer tissues than in normal breast tissues. KK-LC-1 high expression was related to poor survival outcomes in patients with breast cancer. In vitro studies suggested that KK-LC-1 silencing can inhibit triple-negative breast cancer cell proliferation, invasion, migration, and scratch healing ability, increase cell apoptosis ratio, and arrest the cell cycle in the G0-G1 phase. In vivo studies have suggested that KK-LC-1 silencing decreases tumor weight and volume in nude mice. Results showed that KK-CL-1 can regulate the malignant biological behaviors of triple-negative breast cancer via the MAL2/MUC1-C/PI3K/AKT/mTOR pathway. The small-molecule compound Z839878730 had excellent KK-LC-1 targeting ability and cancer cell killing ability. The EC₅₀ value was 9.7 μM for MDA-MB-231 cells and 13.67 µM for MDA-MB-468 cells. Besides, Z839878730 has little tumor-killing effect on human normal mammary epithelial cells MCF10A and can inhibit the malignant biological behaviors of triple-negative breast cancer cells by MAL2/MUC1-C/PI3K/AKT/mTOR pathway.

CONCLUSIONS

Our findings suggest that KK-LC-1 may serve as a novel therapeutic target for triple-negative breast cancer. Z839878730, which targets KK-LC-1, presents a new path for breast cancer clinical treatment.

Relaxin-encapsulated polymeric metformin nanoparticles remodel tumor immune microenvironment by reducing CAFs for efficient triple-negative breast cancer immunotherapy

Cancer-associated fibroblasts (CAFs) are one of the most abundant stromal cells in the tumor microenvironment which mediate desmoplastic response and are the primary driver for an immunosuppressive microenvironment, leading to the failure of triple-negative breast cancer (TNBC) immunotherapy. Therefore, depleting CAFs may enhance the effect of immunotherapy (such as PD-L1 antibody). Relaxin (RLN) has been demonstrated to significantly improve transforming growth factor-β (TGF-β) induced CAFs activation and tumor immunosuppressive microenvironment. However, the short half-life and systemic vasodilation of RLN limit its in vivo efficacy. Here, plasmid encoding relaxin (pRLN) to locally express RLN was delivered with a new positively charged polymer named polymeric metformin (PolyMet), which could increase gene transfer efficiency significantly and have low toxicity that have been certified by our lab before. In order to improve the stability of pRLN in vivo, this complex was further formed lipid poly-γ-glutamic acid (PGA)/PolyMet-pRLN nanoparticle (LPPR). The particle size of LPPR was 205.5 ± 2.9 nm, and the zeta potential was +55.4 ± 1.6 mV. LPPR displayed excellent tumor penetrating efficacy and weaken proliferation of CAFs in 4T1^luc/CAFs tumor spheres in vitro. In vivo, it could reverse aberrantly activated CAFs by decreasing the expression of profibrogenic cytokine and remove the physical barrier to reshape the tumor stromal microenvironment, which enabled a 2.2-fold increase in cytotoxic T cell infiltration within the tumor and a decrease in immunosuppressive cells infiltration. Thus, LPPR was observed retarded tumor growth by itself in the 4T1 tumor bearing-mouse, and the reshaped immune microenvironment further led to facilitate antitumor effect when it combined with PD-L1 antibody (aPD-L1). Altogether, this study presented a novel therapeutic approach against tumor stroma using LPPR to achieve a combination regimen with immune checkpoint blockade therapy against the desmoplastic TNBC model.

Systemic immune mediators reflect tumour-infiltrating lymphocyte intensity and predict therapeutic response in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer (BC). Neoadjuvant chemotherapy has proven efficacy in its treatment, and a pathological complete response (pCR) to therapy is predictive of improved long-term survival. The immune response is key to successful neoadjuvant chemotherapy, as indicated by the relation between the percentage of stromal tumour-infiltrating lymphocytes (TILs) in pre-treated tumour tissue samples and the likelihood of achieving pCR. Here we studied systemic immune mediators from volunteer TNBC patients before undergoing neoadjuvant chemotherapy to determine the systemic response association with TIL intensity, treatment response and survival. Patients were classified into pCR responder or non-responder at time of surgery. We found higher levels of immune mediators before treatment began in patients that went on to be pCR responders versus non-pCR, with area under the curve (AUC) values of 0.64-0.80. We also observed a positive correlation between inflammatory systemic immune mediators and the percentage of TILs in pCR responder patients. Combining TILs and systemic immune mediator levels provided stronger AUC values (range of 0.72-0.82). Last, performing a progression-free survival analysis with several of the systemic cytokines that predict pCR, segregated the patients into long- and short-survival groups based on high and low production of the cytokines, respectively. Our study demonstrates that circulating cytokines, before treatment begins, predict pCR in TNBC patients treated with neoadjuvant chemotherapy. Moreover, they may act as a surrogate marker of high TILs or together with TILs to better predict pCR and survival.

Identifying biomarkers of differential chemotherapy response in TNBC patient-derived xenografts with a CTD/WGCNA approach

Although systemic chemotherapy remains the standard of care for TNBC, even combination chemotherapy is often ineffective. The identification of biomarkers for differential chemotherapy response would allow for the selection of responsive patients, thus maximizing efficacy and minimizing toxicities. Here, we leverage TNBC PDXs to identify biomarkers of response. To demonstrate their ability to function as a preclinical cohort, PDXs were characterized using DNA sequencing, transcriptomics, and proteomics to show consistency with clinical samples. We then developed a network-based approach (CTD/WGCNA) to identify biomarkers of response to carboplatin (MSI1, TMSB15A, ARHGDIB, GGT1, SV2A, SEC14L2, SERPINI1, ADAMTS20, DGKQ) and docetaxel (c, MAGED4, CERS1, ST8SIA2, KIF24, PARPBP). CTD/WGCNA multigene biomarkers are predictive in PDX datasets (RNAseq and Affymetrix) for both taxane- (docetaxel or paclitaxel) and platinum-based (carboplatin or cisplatin) response, thereby demonstrating cross-expression platform and cross-drug class robustness. These biomarkers were also predictive in clinical datasets, thus demonstrating translational potential.

Prognostic Implications of the Residual Tumor Microenvironment after Neoadjuvant Chemotherapy in Triple-Negative Breast Cancer Patients without Pathological Complete Response

With a high risk of relapse and death, and a poor or absent response to therapeutics, the triple-negative breast cancer (TNBC) subtype is particularly challenging, especially in patients who cannot achieve a pathological complete response (pCR) after neoadjuvant chemotherapy (NAC). Although the tumor microenvironment (TME) is known to influence disease progression and the effectiveness of therapeutics, its predictive and prognostic potential remains uncertain. This work aimed to define the residual TME profile after NAC of a retrospective cohort with 96 TNBC patients by immunohistochemical staining (cell markers) and chromogenic in situ hybridization (genetic markers). Kaplan-Meier curves were used to estimate the influence of the selected TME markers on five-year overall survival (OS) and relapse-free survival (RFS) probabilities. The risks of each variable being associated with relapse and death were determined through univariate and multivariate Cox analyses. We describe a unique tumor-infiltrating immune profile with high levels of lymphocytes (CD4, FOXP3) and dendritic cells (CD21, CD1a and CD83) that are valuable prognostic factors in post-NAC TNBC patients. Our study also demonstrates the value of considering not only cellular but also genetic TME markers such as MUC-1 and CXCL13 in routine clinical diagnosis to refine prognosis modelling.

Molecular Classification, Treatment, and Genetic Biomarkers in Triple-Negative Breast Cancer: A Review

Breast cancer is the most common malignancy and the second most common cause of cancer-related mortality in women. Triple-negative breast cancers do not express estrogen receptors, progesterone receptors, or human epidermal growth factor receptor 2 and have a higher recurrence rate, greater metastatic potential, and lower overall survival rate than those of other breast cancers. Treatment of triple-negative breast cancer is challenging; molecular-targeted therapies are largely ineffective and there is no standard treatment. In this review, we evaluate current attempts to classify triple-negative breast cancers based on their molecular features. We also describe promising treatment methods with different advantages and discuss genetic biomarkers and other prediction tools. Accurate molecular classification of triple-negative breast cancers is critical for patient risk categorization, treatment decisions, and surveillance. This review offers new ideas for more effective treatment of triple-negative breast cancer and identifies novel targets for drug development.

Compounds from diverse natural origin against triple-negative breast cancer: A comprehensive review

Triple-negative breast cancer (TNBC) is caused due to the lack of estrogen receptors (ER), progesterone receptors (PR), and human epidermal growth factor 2 (HER2) expression. Triple-negative breast cancer is the most aggressive heterogeneous disease that is capable of producing different clones and mutations. Tumorigenesis in TNBC is caused due to the mutation or overexpression of tumor suppressor genes. It is also associated with mutations in the BRCA gene which is linked to hereditary breast cancer. In addition, PARP proteins and checkpoint proteins also play a crucial function in causing TNBC. Many cell signaling pathways are dysregulated in TNBC. Even though chemotherapy and immunotherapy are good options for TNBC treatment, the response rates are still low in general. Many phytochemicals that are derived from natural compounds have shown very good inhibitions for TNBC. Natural compounds have the great advantage of being less toxic, having lesser side effects, and being easily available. The secondary metabolites such as alkaloids, terpenoids, steroids, and flavonoids in natural products make them promising inhibitors of TNBC. Their compositions also offer vital insights into inhibitory action, which could lead to new cancer-fighting strategies. This review can help in understanding how naturally occurring substances and medicinal herbs decrease specific tumors and pave the way for the development of novel and extremely efficient antitumor therapies.

CODA: a combo-Seq data analysis workflow

The analysis of the combined mRNA and miRNA content of a biological sample can be of interest for answering several research questions, like biomarkers discovery, or mRNA-miRNA interactions. However, the process is costly and time-consuming, separate libraries need to be prepared and sequenced on different flowcells. Combo-Seq is a library prep kit that allows us to prepare combined mRNA-miRNA libraries starting from very low total RNA. To date, no dedicated bioinformatics method exists for the processing of Combo-Seq data. In this paper, we describe CODA (Combo-seq Data Analysis), a workflow specifically developed for the processing of Combo-Seq data that employs existing free-to-use tools. We compare CODA with exceRpt, the pipeline suggested by the kit manufacturer for this purpose. We also evaluate how Combo-Seq libraries analysed with CODA perform compared with conventional poly(A) and small RNA libraries prepared from the same samples. We show that using CODA more successfully trimmed reads are recovered compared with exceRpt, and the difference is more dramatic with short sequencing reads. We demonstrate how Combo-Seq identifies as many genes and fewer miRNAs compared to the standard libraries, and how miRNA validation favours conventional small RNA libraries over Combo-Seq. The CODA code is available at https://github.com/marta-nazzari/CODA.

HDAC7 inhibits cell proliferation via NudCD1/GGH axis in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is the most malignant subtype of breast cancer. In the absence of effective molecular markers for TNBC, there is an urgent clinical need for promising therapeutic target for TNBC. Histone deacetylases (HDACs), key regulators for chromatin remodeling and gene expression, have been suggested to play critical roles in cancer development. However, little is known ~the functions and implications of HDACs in TNBC treatment in the future. By analyzing the expression and prognostic significance of HDAC family members in TNBC through TCGA and METABRIC databases, HDAC7 was found to be downregulated in TNBC samples and the survival of patients with lower expression of HDAC7 was shorter. Furthermore, HDAC7 was negatively associated with NudC domain containing 1 (NudCD1) and γ-glutamyl hydrolase (GGH). Loss of NudCD1 or GGH predicted improved overall survival time (OS) of patients with TNBC. In vitro experiments showed that silencing of HDAC7 enhanced TNBC cell proliferation, while overexpression HDAC7 inhibited TNBC cell proliferation. The results of functional experiments confirmed that HDAC7 negatively modulated GGH and NudCD1 expression. Furthermore, decrease of NudCD1 or GGH inhibited cell proliferation. Notably, the HDAC7-NudCD1/GGH axis was found to be associated with NK cell infiltration. Overall, the present study revealed a novel role of HDAC7-NudCD1/GGH axis in TNBC, which might provide a promising treatment strategy for patients with TNBC.

A MCL-1-targeted photosensitizer to combat triple-negative breast cancer with enhanced photodynamic efficacy, sensitization to ROS-induced damage, and immune response

As growth factor receptor-2 (HER-2), progesterone receptor (PR) and estrogen receptor (ER) are scarce in triple-negative breast cancer (TNBC), it is a great challenge to combat TNBC with high tumor specificity and therapeutic efficacy. Most traditional treatments including surgical resection, chemotherapy, and radiotherapy would more or less cause serious side effects and drug resistance. Photodynamic therapy (PDT) has huge potential in the treatment of TNBC for minimal invasiveness, low toxicity, less drug resistance and high spatiotemporal selectivity. Inspired by the advantages of small-molecule-targeted PDT and the sensitization effect of myeloid cell leukemia-1 (MCL-1) inhibitor, a novel photosensitizer BC-Pc was designed by conjugating MCL-1 inhibitor with zinc phthalocyanines. Owning to 3-chloro-6-methyl-1-benzothiophene-2-carboxylic acid (BC) moiety, BC-Pc exhibits the high affinity towards MCL-1 and reduce its self-aggregation in TNBC cells. Therefore, MCL-1 targeted BC-Pc showed remarkable intracellular fluorescence and ROS generation in TNBC cells. Additionally, BC-Pc can selectively sensitize TNBC cells to ROS-induced damage, resulting in improved therapeutic effect to TNBC cells and negligible toxicity to normal cells. More importantly, BC-Pc can effectively inhibit the migration and invasion of TNBC cells, and enhance immune response, all of which will be beneficial to eradicate TNBC. To the best of our knowledge, BC-Pc is the novel MCL-targeted photosensitizer, which owns the amplified ROS-induced lethality and anticancer immune response for TNBC. Overall, our study provides a promising strategy to achieve targeting and highly efficient therapy of TNBC.

Asiaticoside hampers epithelial–mesenchymal transition by promoting PPARG expression and suppressing P2RX7‐mediated TGF‐β/Smad signaling in triple‐negative breast cancer

Triple-negative breast cancer (TNBC) accounts for 10-20% of all human ductal adenocarcinomas and has a poor prognosis relative to other subtypes because of its high propensity to develop metastases. Here, the anticancer effects of asiaticoside (AC) against TNBC and the possible underlying mechanism were examined. We found that AC inhibited the TGF-β1 expression and the SMAD2/3 phosphorylation in TNBC cells, thereby impairing the TGF-β/SMAD signaling. AC inhibited the migration, invasion, and epithelial-mesenchymal transition (EMT) of TNBC cells by suppressing the TGF-β/SMAD signaling. Meanwhile, AC inhibited the lung metastasis of TNBC cells in vivo and the expression of p-SMAD2/3 and vimentin, and increased the expression of E-cadherin and ZO-1 in the lung. Peroxisome proliferator activated receptor gamma (PPARG) was identified as a potential target of AC. AC increased PPARG expression, while PPARG knockdown attenuated the therapeutic effect of AC. AC-mediated PPARG overexpression suppressed the transcription of P2X purinoceptor 7 (P2RX7). The restoration of P2RX7 reversed the therapeutic effect of AC. These results suggested that AC blocked P2RX7-mediated TGF-β/SMAD signaling by increasing PPARG expression, thereby suppressing EMT in TNBC.

Intercellular Communication Reveals Therapeutic Potential of Epithelial-Mesenchymal Transition in Triple-Negative Breast Cancer

(1) Background: Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with high intra-tumoral heterogeneity. The epithelial-mesenchymal transition (EMT) is one of the inducers of cancer metastasis and migration. However, the description of the EMT process in TNBC using single-cell RNA sequencing (scRNA-seq) remains unclear. (2) Methods: In this study, we analyzed 8938 cellular gene expression profiles from five TNBC patients. We first scored each malignant cell based on functional pathways to determine its EMT characteristics. Then, a pseudo-time trajectory analysis was employed to characterize the cell trajectories. Furthermore, CellChat was used to identify the cellular communications. (3) Results: We identified 888 epithelium-like and 846 mesenchyme-like malignant cells, respectively. A further pseudo-time trajectory analysis indicated the transition trends from epithelium-like to mesenchyme-like in malignant cells. To characterize the potential regulators of the EMT process, we identified 10 dysregulated transcription factors (TFs) between epithelium-like and mesenchyme-like malignant cells, in which overexpressed forkhead box protein A1 (FOXA1) was recognized as a poor prognosis marker of TNBC. Furthermore, we dissected the cell-cell communications via ligand-receptor (L-R) interactions. We observed that tumor-associated macrophages (TAMs) may support the invasion of malignant epithelial cells, based on CXCL-CXCR2 signaling. The tumor necrosis factor (TNF) signaling pathway secreted by TAMs was identified as an outgoing communication pattern, mediating the communications between monocytes/TAMs and malignant epithelial cells. Alternatively, the TNF-related ligand-receptor (L-R) pairs showed promising clinical implications. Some immunotherapy and anti-neoplastic drugs could interact with the L-R pairs as a potential strategy for the treatment of TNBC. In summary, this study enhances the understanding of the EMT process in the TNBC microenvironment, and dissections of EMT-related cell communications also provided us with potential treatment targets.

LC–MS Based Lipidomics Depict Phosphatidylethanolamine as Biomarkers of TNBC MDA-MB-231 over nTNBC MCF-7 Cells

Breast cancer (BC) is the first malignant neoplasm in women, with a high death rate despite early diagnoses and treatment advances. Significant differences exist between the most common BC and triple-negative breast cancer (TNBC). TNBC presents molecular differences such as lacking expression of the estrogen receptor (ER), progesterone receptor (PR), and HER2 proteins, making this cancer have a poor clinical prognostic and lack clear strategies for its treatment. However, growing evidence points to metabolic dysregulation as another differential process between stages and types of BC. Therefore, the study of this crucial hallmark could identify new therapeutic targets to treat this aggressive form of BC. These differences induce an in vitro exploration of the metabolic behavior of the MCF7 cells (nTNBC) and MDA-MB-231 (TNBC) cells under lipidomic based LC–MS. The results show more significant differences in lipid regulation (phosphatidylethanolamine) that could be associated with the aggressiveness and difficulties of the treatment of TNBC.

Long noncoding RNA ST8SIA6-AS1 promotes cell proliferation and metastasis in triple-negative breast cancer by targeting miR-145-5p/CDCA3 to inactivate the p53/p21 signaling pathway

BACKGROUND

Triple-negative breast cancer (TNBC), the most aggressive subtype of breast cancer, always exhibits a poor prognosis due to high risk of early recurrence and distant metastasis. Long noncoding RNAs (lncRNAs) have been reported as crucial regulators in breast cancer. However, the functions and action mechanisms of lncRNA ST8SIA6-AS1 in TNBC are largely unknown.

METHODS

Quantitative real-time PCR and western blot assays were used to measure the expression levels of different genes and proteins. Cell proliferation ability was monitored by CCK-8, colony forming and flow cytometry assays. Wound healing and transwell assays were performed to evaluate cell migration and invasion. The regulatory mechanisms of ST8SIA6-AS1 in TNBC were confirmed by dual luciferase reporter and RIP assays. A mouse xenograft model was established to investigate the role of ST8SIA6-AS1 in TNBC tumor growth.

RESULTS

ST8SIA6-AS1 displayed a higher expression in TNBC cells. Silencing ST8SIA6-AS1 impaired cell proliferation, cell cycle progression, migration, and invasion in vitro, and slowed tumor growth in vivo. Mechanistically, ST8SIA6-AS1 could facilitate the expression of its target CDCA3 (cell division cycle associated protein 3) and inactivate the p53/p21 signaling by inhibiting miR-145-5p. Moreover, miR-145-5p exerted a tumor-suppressive activity by targeting CDCA3. The tumor-suppressive effects induced by ST8SIA6-AS1 knockdown were abated by the down-regulation of miR-145-5p or the up-regulation of CDCA3.

CONCLUSION

ST8SIA6-AS1 exerts an oncogenic role in TNBC by interacting with miR-145-5p to up-regulate CDCA3 expression and inactivate the p53/p21 signaling, highlighting ST8SIA6-AS1 as a promising molecular target to combat TNBC.

Trophoblast cell-surface antigen 2 (TROP2) expression in triple-negative breast cancer

Background

Trophoblast cell-surface antigen 2 (TROP2) is related to tumor proliferation enhancement and poor prognosis. An antibody targeting TROP2 was developed to treat metastatic triple-negative breast cancer (TNBC) which has a limited treatment modality. To characterize the TROP2 expressing tumors in TNBC, we analyzed TROP2 expression in three cohorts; (1) primary tumor without neoadjuvant chemotherapy, (2) primary tumor with neoadjuvant chemotherapy, and (3) metastatic tumor.

Methods

A total of 807 TNBC cases were evaluated for TROP2 immunohistochemical expression. We evaluated the TROP2 H-score distribution in the three cohorts. Tumors were divided into two groups based on TROP2 expression (high vs. low). We analyzed the relationship between clinicopathologic features and markers, including epidermal growth factor receptor, cytokeratin 5/6, p53, and Ki-67, and prognostic significance at high vs. low TROP2 expression.

Results

There was no difference in TROP2 H-score distribution between the three cohorts. Moderate-to-strong membranous expression of TROP2 in at least 10% of tumor cells was present in 662 cases (82.0%) in Cohort 1, 59 cases (89.4%) in Cohort 2, and 23 cases (88.5%) in Cohort 3. There was no significant difference in clinicopathologic features between high vs. low TROP2 in all cohorts. TROP2 H-score was an independent poor prognostic factor for overall survival in Cohort 3.

Conclusions

TNBC showed similar TROP2 expression regardless of neoadjuvant treatment or primary tumor/metastasis. Although the prognostic significance of TROP2 expression in metastatic TNBC has been revealed, further evaluation of the predictive value of TROP2 expression for targeted therapy is needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-10076-7.

LINC00511/hsa-miR-573 axis-mediated high expression of Gasdermin C associates with dismal prognosis and tumor immune infiltration of breast cancer

Breast cancer (BC) is considered the second commonest human carcinoma and the most incident and mortal in the female population. Despite promising treatments for breast cancer, mortality rates of metastatic disease remain high. Gasdermin C (GSDMC) is an affiliate of the gasdermin (GSDM) family, which is involved in the process of pyroptosis. Pyroptosis is implicated in tumorigenesis, but the role of GSDMC in cancer cells is yet to be fully elucidated. In this study, we investigated the role and mechanism of GSDMC in breast cancer. We conducted a pan-cancer analysis of the expression and prognosis of GSDMC utilizing multidimensional data from The Cancer Genome Atlas (TCGA). We investigated GSDMC expression levels in 15 BC tissues and matched adjacent normal tissues by immunohistochemistry (IHC). Further verification was performed in the Gene Expression Omnibus (GEO) database. We discovered that elevated GSDMC expression was considerably linked to a worse prognosis in breast invasive carcinoma (BRCA). Next, we identified noncoding RNAs (ncRNAs) which contributing to higher expression of GSDMC by a series of expression, survival, and correlation analysis. We finally identified LINC00511/hsa-miR-573 axis to be the most promising ncRNA-associated pathways that account for GSDMC in BRCA. Furthermore, we demonstrated the significant correlations between GSDMC expression and immune infiltrates, immune checkpoints, and immune markers in BRCA. This study illustrated that ncRNAs-mediated upregulation of GSDMC linked to dismal prognosis and also exhibited a correlation with tumor immune cell infiltration in BRCA. It is anticipated to offer novel ideas for the link between pyroptosis and tumor immunotherapy.

Glycoproteomics Identifies Plexin-B3 as a Targetable Cell Surface Protein Required for the Growth and Invasion of Triple-Negative Breast Cancer Cells

Driven by the lack of targeted therapies, triple-negative breast cancers (TNBCs) have the worst overall survival of all breast cancer subtypes. Considering that cell surface proteins are favorable drug targets and are predominantly glycosylated, glycoproteome profiling has significant potential to facilitate the identification of much-needed drug targets for TNBCs. Here, we performed N-glycoproteomics on six TNBCs and five normal control (NC) cell lines using hydrazide-based enrichment. Quantitative proteomics and integrative data mining led to the discovery of Plexin-B3 (PLXNB3), a previously undescribed TNBC-enriched cell surface protein. Furthermore, siRNA knockdown and CRISPR-Cas9 editing of in vitro and in vivo models show that PLXNB3 is required for TNBC cell line growth, invasion, and migration. Altogether, we provide insights into N-glycoproteome remodeling associated with TNBCs and functional evaluation of an extracted target, which indicate the surface protein PLXNB3 as a potential therapeutic target for TNBCs.

Clinical applications of mass spectrometry-based proteomics in cancer: where are we?

Tumor tissue processing methodologies in combination with data-independent acquisition mass spectrometry (DIA-MS) have emerged that can comprehensively analyze the proteome of multiple tumor samples accurately and reproducibly. Increasing recognition and adoption of these technologies has resulted in a tranche of studies providing novel insights into cancer classification systems, functional tumor biology, cancer biomarkers, treatment response and drug targets. Despite this, with some limited exceptions, MS-based proteomics has not yet been implemented in routine cancer clinical practice. Here, we summarize the use of DIA-MS in studies that may pave the way for future clinical cancer applications, and highlight the role of alternative MS technologies and multi-omic strategies. We discuss limitations and challenges of studies in this field to date and propose steps for integrating proteomic data into the cancer clinic. This article is protected by copyright. All rights reserved.