Gasdermin E suppresses tumour growth by activating anti-tumour immunity.

Cleavage of the gasdermin proteins to produce pore-forming amino-terminal fragments causes inflammatory cell death (pyroptosis)1. Gasdermin E (GSDME, also known as DFNA5)-mutated in familial ageing-related hearing loss2-can be cleaved by caspase 3, thereby converting noninflammatory apoptosis to pyroptosis in GSDME-expressing cells3-5. GSDME expression is suppressed in many cancers, and reduced GSDME levels are associated with decreased survival as a result of breast cancer2,6, suggesting that GSDME might be a tumour suppressor. Here we show that 20 of 22 tested cancer-associated GSDME mutations reduce GSDME function. In mice, knocking out Gsdme in GSDME-expressing tumours enhances, whereas ectopic expression in Gsdme-repressed tumours inhibits, tumour growth. This tumour suppression is mediated by killer cytotoxic lymphocytes: it is abrogated in perforin-deficient mice or mice depleted of killer lymphocytes. GSDME expression enhances the phagocytosis of tumour cells by tumour-associated macrophages, as well as the number and functions of tumour-infiltrating natural-killer and CD8+ T lymphocytes. Killer-cell granzyme B also activates caspase-independent pyroptosis in target cells by directly cleaving GSDME at the same site as caspase 3. Uncleavable or pore-defective GSDME proteins are not tumour suppressive. Thus, tumour GSDME acts as a tumour suppressor by activating pyroptosis, enhancing anti-tumour immunity.

Neoadjuvant everolimus plus letrozole versus fluorouracil, epirubicin and cyclophosphamide for ER-positive, HER2-negative breast cancer: a randomized pilot trial.

BACKGROUND: Here we evaluated the feasibility, efficacy, tolerability, and treatment-mediated immune modulation of neoadjuvant everolimus plus letrozole versus chemotherapy in treating postmenopausal patients with ER-positive, HER2-negative breast cancer. METHODS: Postmenopausal women with ER-positive, HER2-negative breast cancer who had a primary tumor > 2 cm or positive axillary lymph node(s) proofed by biopsy were randomly (1,1) enrolled to receive neoadjuvant everolimus plus letrozole for 18 weeks or fluorouracil, epirubicin plus cyclophosphamide (FEC) for 6 cycles before surgery. Primary outcome was feasibility of the trial. Secondary outcome included ultrasound response rate, pathological complete response rate, breast-conserving surgery rate, toxicities, treatment-mediated immune modulation and biomarkers. RESULTS: Forty patients were randomized. Completion rate was 90.0% in the neoadjuvant endocrine therapy (NET) arm but 70.0% in the neoadjuvant chemotherapy (NAC) arm. The ultrasound response rate was 65.0% in NET arm and 40.0% in FEC arm, respectively. In terms of the adverse events, clearly favored NET arm. Everolimus plus letrozole increased the ratio of peripheral Tregs to CD4+ T cells and tumor PD-L1 expression, and decreased Ki67 index and tumor-infiltrating Tregs, and patients with a greater increase of tumor-specific CTLs showed more sensitive to NET. CONCLUSION: This pilot trial showed that neoadjuvant everolimus plus letrozole might achieve a favorable ultrasound response rate with low toxicities in treating postmenopausal ER-positive, HER2-negative breast cancer patients. Everolimus plus letrozole might have positive antitumoral immunity effects. Further large randomized controlled trials are needed to confirm our findings. TRAIL REGISTRATION: A Trial of Neoadjuvant Everolimus Plus Letrozole Versus FEC in Women With ER-positive, HER2-negative Breast Cancer, registered on 07/04/2016 and first posted on 18/04/2016, NCT02742051 .

Antibody against early driver of neurodegeneration cis P-tau blocks brain injury and tauopathy.

Traumatic brain injury (TBI), characterized by acute neurological dysfunction, is one of the best known environmental risk factors for chronic traumatic encephalopathy and Alzheimer's disease, the defining pathologic features of which include tauopathy made of phosphorylated tau protein (P-tau). However, tauopathy has not been detected in the early stages after TBI, and how TBI leads to tauopathy is unknown. Here we find robust cis P-tau pathology after TBI in humans and mice. After TBI in mice and stress in vitro, neurons acutely produce cis P-tau, which disrupts axonal microtubule networks and mitochondrial transport, spreads to other neurons, and leads to apoptosis. This process, which we term 'cistauosis', appears long before other tauopathy. Treating TBI mice with cis antibody blocks cistauosis, prevents tauopathy development and spread, and restores many TBI-related structural and functional sequelae. Thus, cis P-tau is a major early driver of disease after TBI and leads to tauopathy in chronic traumatic encephalopathy and Alzheimer's disease. The cis antibody may be further developed to detect and treat TBI, and prevent progressive neurodegeneration after injury.

Adjuvant radiotherapy and chemotherapy for patients with breast phyllodes tumors: a systematic review and meta-analysis.

BACKGROUND: As the efficacy of radiotherapy and chemotherapy for treatment of phyllodes tumors (PTs) remains unclear, this study aimed to review all available data and evaluate the roles of radiotherapy and chemotherapy in PT treatment. METHODS: We performed a comprehensive search of databases, including PubMed, Web of Science and the Cochrane Library. The outcomes of interest included the local recurrence (LR) rate, metastasis rate, disease-free survival rate and overall survival rate. RESULTS: Seventeen studies enrolling 696 patients were included in this random effect meta-analysis. Subgroup analysis and meta-regression were also conducted to determine study heterogeneity. A pooled local recurrence rate of 8% (95% CI: 1-22%) was observed with a statistical heterogeneity of I2 = 86.6% (p < 0.01) for radiotherapy. This was lower than the recurrence rate of 12% for simple surgical treatment (95% CI: 7-18%). Meta-regression analysis found that surgical margin status was the main source of heterogeneity (p = 0.04). The metastasis rate of 4% (95% CI: 0-11%) for patients receiving radiotherapy without significant heterogeneity was also lower than the rate for the simple surgery group (8, 95% CI: 3-15%). The available data for chemotherapy were too limited to support meta-analysis. Accordingly, we offer a pure review of these data. CONCLUSION: Our findings suggest that radiotherapy is effective in achieving local disease control and preventing metastasis.

Molecular epidemiology and virulence characteristics of Staphylococcus aureus nasal colonization in medical laboratory staff: comparison between microbiological and non-microbiological laboratories.

BACKGROUND: Medical laboratory staff are a high-risk population for colonization of Staphylococcus aureus (S. aureus) due to direct and dense contact with the pathogens; however, there is limited information about this colonization. This study sought to determine the prevalence and molecular characteristics of nasal colonization by S. aureus in medical laboratory staff in Guangzhou, southern China, and to compare the differences between microbiological laboratory (MLS) and non-microbiological laboratory (NMLS) staff. METHODS: S. aureus colonization was assessed by nasal swab cultures from 434 subjects, including 130 MLSs and 304 NMLSs from 33 hospitals in Guangzhou. All S. aureus isolates underwent the antimicrobial susceptibility test, virulence gene detection and molecular typing. RESULTS: The overall prevalence of S. aureus carriage was 20.1% (87/434), which was higher in MLSs than in NMLSs (26.2% vs. 17.4%, P < 0.05), while the prevalence of Methicillin-resistant S. aureus (MRSA) was similar. Living with hospital staff was associated with S. aureus carriage. The majority of the isolates harboured various virulence genes, and those in MLSs appeared less resistant to antibiotics and more virulent than their counterparts. A total of 37 different spa types were detected; among these, t338, t437, t189 and t701 were the most frequently encountered types. T338 was the main spa type contributing to nasal colonization Methicillin-sensitive S. aureus (MSSA) (13.0%), and t437-SCCmec IV was predominant in MRSA isolates (40%). CONCLUSIONS: These findings provide insight into the risk factors, molecular epidemiology and virulence gene profiles of S. aureus nasal carriage among the medical laboratory staff in Guangzhou.

A case of Cardiobacterium valvarum endocarditis with cerebral hemorrhage after MVR, TVP and vegetation removal operation.

BACKGROUND: Cardiobacterium is a fastidious Gram-negative bacillus, and is a rare human pathogen in clinical settings. Herein, we describe a case of Cardiobacterium valvarum (C. valvarum) endocarditis with a rare complication of cerebral hemorrhage after mitral valve replacement (MVR), tricuspid valve prosthesis (TVP) and vegetation removal operation. CASE PRESENTATION: A 41-year-old woman who had a history of gingivitis developed into infective endocarditis due to the infection of C. valvarum. Then, she was hospitalized to receive MVR, TVP and vegetation removal operation. The indicators of patient tended to be normal until the abrupt cerebral hemorrhage occurred on day 15 after operation. This is the first well-described case of C. valvarum infection in China, and the first report of C. valvarum endocarditis with cerebral hemorrhage after MVR, TVP and vegetation removal operation worldwide. CONCLUSIONS: We reported the first case of C. valvarum infection in China clinically, with a rare complication of cerebral hemorrhage after MVR, TVP and vegetation removal operation.

Potentiated DNA Damage Response in Circulating Breast Tumor Cells Confers Resistance to Chemotherapy.

Circulating tumor cells (CTCs) are seeds for cancer metastasis and are predictive of poor prognosis in breast cancer patients. Whether CTCs and primary tumor cells (PTCs) respond to chemotherapy differently is not known. Here, we show that CTCs of breast cancer are more resistant to chemotherapy than PTCs because of potentiated DNA repair. Surprisingly, the chemoresistance of CTCs was recapitulated in PTCs when they were detached from the extracellular matrix. Detachment of PTCs increased the levels of reactive oxygen species and partially activated the DNA damage checkpoint, converting PTCs to a CTC-like state. Inhibition of checkpoint kinases Chk1 and Chk2 in CTCs reduces the basal checkpoint response and sensitizes CTCs to DNA damage in vitro and in mouse xenografts. Our results suggest that DNA damage checkpoint inhibitors may benefit the chemotherapy of breast cancer patients by suppressing the chemoresistance of CTCs and reducing the risk of cancer metastasis.

MiR-320a acts as a prognostic factor and Inhibits metastasis of salivary adenoid cystic carcinoma by targeting ITGB3.

BACKGROUND: Salivary Adenoid cystic carcinoma (SACC) patients with local invasion and lung metastasis are often resistant to conventional therapy such as operation, chemotherapy and radiotherapy. To explore the underling mechanisms, we studied the roles of miRNA in regulating invasiveness of SACC cells. METHODS: MicroRNA profiling was done in SACC cells with microarray. MiRNA mimics or antisense oligonucleotide was transfected and invasiveness of SACC cells was evaluated by adhesion assay and transwell assay. The target gene of miRNA was identified by luciferase reporter assay and "rescue" experiment. Tumor metastasis was evaluated by BALB/c-nu mice xenografts. MiRNA and its target gene expression were identified by in-situ hybridization and immunohistochemistry respectively, in 302 patients from affiliated hospitals of Sun Yat-sen University and in 148 patients from affiliated hospitals of Central South University, and correlated to the clinicopathological status of the patients. RESULTS: MiR-320a was down-regulated in high lung metastatic ACCM and SACC-LM cells compared with the corresponding low metastatic ACC2 and SACC-83 cells, and inhibited adhesion, invasion and migration of SACC cells by targeting integrin beta 3 (ITGB3). In vivo, enforced miR-320a expression suppressed metastasis of SACC xenografts. In the two independent sets, miR-320a was downregulated in primary SACCs with metastasis compared to those without metastasis, and low expression of this miRNA predicts poor patient survival and rapid metastasis. Multivariate analysis showed that miR-320a expression was an independent indicator of lung metastasis. CONCLUSIONS: MiR-320a inhibits metastasis in SACCs by targeting ITGB3 and may serve as a therapeutic target and prognostic marker in salivary cancers.

Pin1 cysteine-113 oxidation inhibits its catalytic activity and cellular function in Alzheimer's disease.

The unique proline isomerase Pin1 is pivotal for protecting against age-dependent neurodegeneration in Alzheimer's disease (AD), with its inhibition providing a molecular link between tangle and plaque pathologies. Pin1 is oxidatively modified in human AD brains, but little is known about its regulatory mechanisms and pathological significance of such Pin1 modification. In this paper, our determination of crystal structures of oxidized Pin1 reveals a series of Pin1 oxidative modifications on Cys113 in a sequential fashion. Cys113 oxidization is further confirmed by generating antibodies specifically recognizing oxidized Cys113 of Pin1. Furthermore, Pin1 oxidation on Cys113 inactivates its catalytic activity in vitro, and Ala point substitution of Cys113 inactivates the ability of Pin1 to isomerize tau as well as to promote protein turnover of tau and APP. Moreover, redox regulation affects Pin1 subcellular localization and Pin1-mediated neuronal survival in response to hypoxia treatment. Importantly, Cys113-oxidized Pin1 is significantly increased in human AD brain comparing to age-matched controls. These results not only identify a novel Pin1 oxidation site to be the critical catalytic residue Cys113, but also provide a novel oxidative regulation mechanism for inhibiting Pin1 activity in AD. These results suggest that preventing Pin1 oxidization might help to reduce the risk of AD.

Serotype distribution and antibiotic resistance of Streptococcus pneumoniae isolates collected at a Chinese hospital from 2011 to 2013.

BACKGROUND: Streptococcus pneumoniae infections are a major cause of global morbidity and mortality, and the emergence of antibiotic-resistant Streptococcus pneumoniae strains has been increasingly reported. This study provides up-to-date information on bacterial serotype distribution and drug resistance from S. pneumoniae clinical isolates that could guide prevention and treatment strategies for pneumococcal disease in China. METHODS: A total of 94 S. pneumoniae isolates were collected from outpatients and inpatients at one Chinese hospital from 2011-2013. Drug susceptibility and resistance was determined by minimum inhibitory concentrations (MICs). Capsular serotypes were identified by the quellung reaction test and multiplex polymerase chain reaction. RESULTS: Fifteen serotypes were identified among the 94 S. pneumoniae clinical isolates that were collected. Prevalent serotypes were 19F (42.6 %), 19A (8.5 %), 3 (8.5 %), and 6B (7.4 %). Potential immunization coverage rates for the 7-, 10- and 13-valent pneumococcal polysaccharide conjugate vaccines were 59.6, 62.6, and 79.6 %, respectively. Resistance rates to tetracycline, erythromycin, and trimethoprim/sulfamethoxazole were 91.2, 80.2 and 63.8 %, respectively. Resistance rates to penicillin, amoxicillin, ceftriaxone, and cefotaxime were 47.3, 34.1, 19.8, and 18.7 %, respectively. In almost all cases, antimicrobial resistance of the S. pneumoniae isolates in patients five years or younger was higher than isolates collected from patients aged 51 years or older. CONCLUSION: Prevalent serotypes among the 94 S. pneumoniae clinical isolates were 19F, 19A, 3, and 6B. The 13-valent pneumococcal polysaccharide conjugate vaccine covered the majority of the serotypes identified in this sample. Drug resistance varied among different serotypes and age groups. Clinical precautions should be taken to avoid the development of multidrug resistance in this potential human pathogen.

Differences in Staphylococcus aureus nasal carriage and molecular characteristics among community residents and healthcare workers at Sun Yat-Sen University, Guangzhou, Southern China.

BACKGROUND: The pathogenic potential and commensal nature of Staphylococcus aureus allows for easy transmission both within and outside of the hospital environment, and nasal carriage may be responsible for some serious infections. This study aimed to determine the molecular and epidemiological characteristics of nasal colonization by S. aureus in community residents (CR) and healthcare workers (HW) at Sun Yat-Sen University, Guangzhou, China. METHODS: A total of 589 volunteers, both CR (n = 297) and HW (n = 292), were recruited. Each subject completed a questionnaire, and specimens were obtained from the anterior nares for S. aureus screening. Genotypic analysis included pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), staphylococcal cassette chromosome mec (SCCmec) typing, and virulence gene detection. RESULTS: A total of 138 S. aureus isolates were recovered from separate subjects (23.4%, 138/589), with four isolates showing methicillin resistance (0.7%, 4/589). The prevalence of S. aureus carriage was 25.3% (75/297) in CR and 21.6% (63/292) in HW. Methicillin-resistant S. aureus (MRSA) were isolated from one CR (0.3%, 1/297) and three HW (1.0%, 3/292). The most common risk factors for S. aureus carriage in CR were being male, age ≤ 30 years, and nasal cavity cleaning habits. Having a household member in the healthcare profession was associated with increased risk among HW. Sequence type (ST)188 and ST59 were the most prevalent among the 20 observed STs, accounting for 14.6% and 12.2% of all isolates, respectively. The four MRSA isolates presented four different STs, with one isolate carrying a type IVa SCCmec element and the other three isolates containing type III SCCmec. PFGE analysis grouped the 129 isolates into 23 pulsotypes, with profiles A, N, E, L, and O the most prevalent. The Panton-Valentine leucocidin gene (pvl) was identified in two of the 138 isolates, while 57.5% of isolates carried both the Staphylococcus aureus enterotoxin A (sea) and enterotoxin B (seb) genes. CONCLUSIONS: These data indicate a low prevalence of nasal MRSA carriage but evidence of molecular heterogeneity among S. aureus isolates from CR and HW at Sun Yat-Sen University, Guangzhou. Differences in epidemiological and molecular characteristics of S. aureus between CR and HW populations may be useful for the understanding and prevention of S. aureus infection.

YTHDF2 favors protumoral macrophage polarization and implies poor survival outcomes in triple negative breast cancer.

Patients with triple-negative breast cancer (TNBC) frequently experience resistance to chemotherapy, leading to recurrence. The approach of optimizing anti-tumoral immunological effect is promising in overcoming such resistance, given the heterogeneity and lack of biomarkers in TNBC. In this study, we focused on YTHDF2, an N6-methyladenosine (m6A) RNA-reader protein, in macrophages, one of the most abundant intra-tumoral immune cells. Using single-cell sequencing and ex vivo experiments, we discovered that YTHDF2 significantly promotes pro-tumoral phenotype polarization of macrophages and is closely associated with down-regulated antigen-presentation signaling to other immune cells in TNBC. The in vitro deprivation of YTHDF2 favors anti-tumoral effect. Expressions of multiple transcription factors, especially SPI1, were consistently observed in YTHDF2-high macrophages, providing potential therapeutic targets for new strategies. In conclusion, YTHDF2 in macrophages appears to promote pro-tumoral effects while suppressing immune activity, indicating the treatment targeting YTHDF2 or its transcription factors could be a promising strategy for chemoresistant TNBC.

The Detection of Exosomal PD-L1 in Peripheral Blood.

Peripheral blood is a source for liquid biopsy, which can meet the requirements of pretreatment disease typing to determine precise targeted therapy and monitoring of posttreatment minimal residual disease monitoring. Compared with ctDNA and CTC, exosomes have a higher concentration, good biostability, biocompatibility, low immunogenicity, and low toxicity in peripheral blood. Tumors generally secrete a large amounts of exosomes, which have potential pathophysiological roles in tumor progression. With the continuous improvement of liquid biopsy technology, many researchers have found that exosomes are the key for tumor PD-L1 to exert its role, which may be the mechanism that leads to PD-L1 and/or PD-1 inhibitor therapy resistance. Namely, tumor-derived exosomes may mediate systemic immunosuppression against PD-1 or PD-L1 inhibitor therapy, endogenous tumor cell-derived exosomal PD-L1, and tumor microenvironment-derived exosomes. Induction of PD-L1 by exosomes may be a crucial mechanisms of exosome-mediated antitumor immune tolerance. This article reviews the relationship between the detection of peripheral blood exosomal PD-L1 and tumor progression and the mechanism of exosomal PD-L1 in tumor immunotherapy.

Nanoparticles (NPs)-mediated systemic mRNA delivery to reverse trastuzumab resistance for effective breast cancer therapy.

Monoclonal antibody-based therapy has achieved great success and is now one of the most crucial therapeutic modalities for cancer therapy. The first monoclonal antibody authorized for treating human epidermal growth receptor 2 (HER2)-positive breast cancer is trastuzumab. However, resistance to trastuzumab therapy is frequently encountered and thus significantly restricts the therapeutic outcomes. To address this issue, tumor microenvironment (TME) pH-responsive nanoparticles (NPs) were herein developed for systemic mRNA delivery to reverse the trastuzumab resistance of breast cancer (BCa). This nanoplatform is comprised of a methoxyl-poly (ethylene glycol)-b-poly (lactic-co-glycolic acid) copolymer with a TME pH-liable linker (Meo-PEG-Dlink m -PLGA) and an amphiphilic cationic lipid that can complex PTEN mRNA via electrostatic interaction. When the long-circulating mRNA-loaded NPs build up in the tumor after being delivered intravenously, they could be efficiently internalized by tumor cells due to the TME pH-triggered PEG detachment from the NP surface. With the intracellular mRNA release to up-regulate PTEN expression, the constantly activated PI3K/Akt signaling pathway could be blocked in the trastuzumab-resistant BCa cells, thereby resulting in the reversal of trastuzumab resistance and effectively suppress the development of BCa.

Nanoblock-mediated selective oncolytic polypeptide therapy for triple-negative breast cancer.

Rationale: Broad-spectrum oncolytic peptides (Olps) constitute potential therapeutic options for treating heterogeneous triple-negative breast cancer (TNBC); however, their clinical application is limited owing to high toxicity. Methods: A nanoblock-mediated strategy was developed to induce selective anticancer activity of synthetic Olps. A synthetic Olp, C12-PButLG-CA, was conjugated to the hydrophobic or hydrophilic terminal of a poly(ethylene oxide)-b-poly(propylene oxide) nanoparticle or a hydrophilic poly(ethylene oxide) polymer. A nanoblocker, that can significantly reduce the toxicity of Olp, was screened out through hemolytic assay, and then Olps were conjugated to the nanoblock via a tumor acidity-cleavable bond to obtain the selective RNolp ((mPEO-PPO-CDM)2-Olp). The tumor acidity responsive membranolytic activity, in vivo toxicity and anti-tumor efficacy of RNolp were determined. Results: We found that the conjugation of Olps to the hydrophobic core of a nanoparticle but not the hydrophilic terminal or a hydrophilic polymer restricts their motion and drastically reduces their hemolytic activity. We then covalently conjugated Olps to such a nanoblock via a cleavable bond that can be hydrolyzed in the acidic tumor environment, yielding a selective RNolp molecule. At physiological pH (pH 7.4), RNolp remained stable with the Olps shielded by nanoblocks and exhibited low membranolytic activity. At the acidic tumor environment (pH 6.8), Olps could be released from the nanoparticles via the hydrolysis of the tumor acidity-cleavable bonds and exerted membranolytic activity against TNBC cells. RNolp is well tolerated in mice and demonstrated high antitumor efficacy in orthotopic and metastatic mouse models of TNBC. Conclusion: We developed a simple nanoblock-mediated strategy to induce a selective cancer therapy of Olps for TNBC.

Repolarization of macrophages to improve sorafenib sensitivity for combination cancer therapy.

Sorafenib is the first line drug for hepatocellular carcinoma (HCC) therapy. However, HCC patients usually acquire resistance to sorafenib treatment within 6 months. Recent evidences have shown that anticancer drugs with antiangiogenesis effect (e.g., sorafenib) can aggravate the hypoxia microenvironment and promote the infiltration of more tumor-associated macrophages (TAMs) into the tumor tissues. Therefore, repolarization of TAMs phenotype could be expected to not only eliminate the influence of TAMs on sorafenib lethality to HCC cells, but also provide an additional anticancer effect to achieve combination therapy. However, immune side effects remain a great challenge due to the non-specific macrophage repolarization in normal tissues. We herein employed a tumor microenvironment (TME) pH-responsive nanoplatform to concurrently transport sorafenib and modified resiquimod (R848-C16). This nanoparticle (NP) platform is made with a TME pH-responsive methoxyl-poly(ethylene glycol)-b-poly(lactic-co-glycolic acid) copolymer. After intravenous administration, the co-delivery NPs could highly accumulate in the tumor tissues and then respond to the TME pH to detach their surface PEG chains. With this PEG detachment to enhance uptake by TAMs and HCC cells, the co-delivery NPs could combinatorially inhibit HCC tumor growth via sorafenib-mediated lethality to HCC cells and R848-mediated repolarization of TAMs into tumoricidal M1-like macrophages. STATEMENT OF SIGNIFICANCE: Anticancer drugs with antiangiogenesis effect (e.g., sorafenib) can aggravate the hypoxia microenvironment and promote the infiltration of more tumor-associated macrophages (TAMs) into the tumor tissues to restrict the anticancer effect. In this work, we designed and developed a tumor microenvironment (TME) pH-responsive nanoplatform for systemic co-delivery of sorafenib and resiquimod in hepatocellular carcinoma (HCC) therapy. These co-delivery NPs show high tumor accumulation and could respond to the TME pH to enhance uptake by TAMs and HCC cells. With the sorafenib-mediated lethality to HCC cells and R848-mediated repolarization of TAMs, the co-delivery NPs show a combinational inhibition of HCC tumor growth in both xenograft and orthotopic tumor models.

Overexpressed Cyclin D1 and CDK4 proteins are responsible for the resistance to CDK4/6 inhibitor in breast cancer that can be reversed by PI3K/mTOR inhibitors.

CDK4/6 inhibitors are the standard treatment in advanced HR+/HER2- breast cancer patients. Nevertheless, the resistance to CDK4/6 inhibitors is inevitable and the strategies to overcome resistance are of great interest. Here, we show that the palbociclib-resistant breast cancer cells expressed significantly higher levels of Cyclin D1 and CDK4 proteins because of upregulated protein synthesis. Silencing Cyclin D1 or CDK4 led to cell cycle arrest while silencing Cyclin E1 or CDK2 restored the sensitivity to palbociclib. Furthermore, PI3K/mTOR pathway was hyper-activated in palbociclib-resistant cells, leading to more phosphorylated 4E-BP1 and higher levels of Cyclin D1 and CDK4 translation. Targeting PI3K/mTOR pathway with a specific PI3Kα inhibitor (BYL719) or an mTOR inhibitor (everolimus) reduced the protein levels of Cyclin D1 and CDK4, and restored the sensitivity to palbociclib. The tumor samples expressed significantly higher levels of Cyclin D1, CDK4, p-AKT and p-4E-BP1 after progression on palbociclib treatment. In conclusion, our findings suggest that overexpressed Cyclin D1 and CDK4 proteins lead to the resistance to CDK4/6 inhibitor and PI3K/mTOR inhibitors are able to restore the sensitivity to CDK4/6 inhibitors, which provides the biomarker and rationale for the combinational use of CDK4/6 inhibitors and PI3K/mTOR inhibitors after CDK4/6 inhibitor resistance in breast cancer.

LncRNA EILA promotes CDK4/6 inhibitor resistance in breast cancer by stabilizing cyclin E1 protein.

CDK4/6 inhibitors (CDK4/6i) plus endocrine therapy are now standard first-line therapy for advanced HR+/HER2- breast cancer, but developing resistance is just a matter of time in these patients. Here, we report that a cyclin E1-interacting lncRNA (EILA) is up-regulated in CDK4/6i-resistant breast cancer cells and contributes to CDK4/6i resistance by stabilizing cyclin E1 protein. EILA overexpression correlates with accelerated cell cycle progression and poor prognosis in breast cancer. Silencing EILA reduces cyclin E1 protein and restores CDK4/6i sensitivity both in vitro and in vivo. Mechanistically, hairpin A of EILA binds to the carboxyl terminus of cyclin E1 protein and hinders its binding to FBXW7, thereby blocking its ubiquitination and degradation. EILA is transcriptionally regulated by CTCF/CDK8/TFII-I complexes and can be inhibited by CDK8 inhibitors. This study unveils the role of EILA in regulating cyclin E1 stability and CDK4/6i resistance, which may serve as a biomarker to predict therapy response and a potential therapeutic target to overcome resistance.

CCL18 signaling from tumor-associated macrophages activates fibroblasts to adopt a chemoresistance-inducing phenotype.

The heterogeneity of cancer-associated fibroblasts (CAFs) might be ascribed to differences in origin. CD10 and GPR77 have been reported to identify a chemoresistance-inducing CAF subset in breast cancer. However, the precise mechanism for the formation of the CD10+GPR77+ CAFs remains unknown. In this study, we found that CCL18 expression was positively correlated with the density of CD10+GPR77+ CAFs in breast cancer and associated with a poor response to chemotherapy. Moreover, CCL18 secreted by tumor-associated macrophages (TAMs) activated a CD10+GPR77+ CAF phenotype in normal breast-resident fibroblasts (NBFs), which could then enrich cancer stem cells (CSCs) and induce chemoresistance in breast cancer cells. Mechanistically, CCL18 activated NF-κB signaling via PITPNM3 and thus enhanced the production of IL-6 and IL-8. Furthermore, intratumoral CCL18 injection significantly induced the activation of NBFs and the chemoresistance of xenografts in vivo. In addition, targeting CCL18 by anti-CCL18 antibody could inhibit the formation of CD10+GPR77+ CAFs and recover the chemosensitivity in vivo, leading to effective tumor control. Collectively, these findings reveal that inflammatory signaling crosstalk between TAMs and fibroblasts is responsible for the formation of the CD10+GPR77+ CAFs, suggesting CCL18-PITPNM3 signaling is a potential therapeutic target to block the activation of this specific CAF subtype and tumor chemoresistance.

Up-regulation of miR-21 mediates resistance to trastuzumab therapy for breast cancer.

Trastuzumab resistance emerges to be a major issue in anti-human epidermal growth factor receptor 2 (HER2) therapy for breast cancers. Here, we demonstrated that miR-21 expression was up-regulated and its function was elevated in HER2(+) BT474, SKBR3, and MDA-MB-453 breast cancer cells that are induced to acquire trastuzumab resistance by long-term exposure to the antibody, whereas protein expression of the PTEN gene, a miR-21 target, was reduced. Blocking the action of miR-21 with antisense oligonucleotides re-sensitized the resistant cells to the therapeutic activities of trastuzumab by inducing growth arrest, proliferation inhibition, and G(1)-S cell cycle checking in the presence of the antibody. Ectopic expression of miR-21 in HER2(+) breast cancer cells confers resistance to trastuzumab. Rescuing PTEN expression with a p3XFLAG-PTEN-mut construct with deleted miR-21 targeting sequence at its 3' UTR restored the growth inhibition of trastuzumab in the resistant cells by inducing PTEN activation and AKT inhibition. In vivo, administering miR-21 antisense oligonucleotides restored trastuzumab sensitivity in the resistant breast cancer xenografts by inducing PTEN expression, whereas injection of miR-21 mimics conferred trastuzumab resistant in the sensitive breast tumors via PTEN silence. Up-regulatin of miR-21 in tumor biopsies obtained from patients receiving pre-operative trastuzumab therapy was associated with poor trastuzumab response. Therefore, miR-21 overexpression contributes to trastuzumab resistance in HER2(+) breast cancers and antagonizing miR-21 demonstrates therapeutic potential by sensitizing the malignancy to anti-HER2 treatment.