Acetylation of MORC2 by NAT10 regulates cell-cycle checkpoint control and resistance to DNA-damaging chemotherapy and radiotherapy in breast cancer.

MORC family CW-type zinc finger 2 (MORC2) is an oncogenic chromatin-remodeling enzyme with an emerging role in DNA repair. Here, we report a novel function for MORC2 in cell-cycle checkpoint control through an acetylation-dependent mechanism. MORC2 is acetylated by the acetyltransferase NAT10 at lysine 767 (K767Ac) and this process is counteracted by the deacetylase SIRT2 under unperturbed conditions. DNA-damaging chemotherapeutic agents and ionizing radiation stimulate MORC2 K767Ac through enhancing the interaction between MORC2 and NAT10. Notably, acetylated MORC2 binds to histone H3 phosphorylation at threonine 11 (H3T11P) and is essential for DNA damage-induced reduction of H3T11P and transcriptional repression of its downstream target genes CDK1 and Cyclin B1, thus contributing to DNA damage-induced G2 checkpoint activation. Chemical inhibition or depletion of NAT10 or expression of an acetylation-defective MORC2 (K767R) forces cells to pass through G2 checkpoint, resulting in hypersensitivity to DNA-damaging agents. Moreover, MORC2 acetylation levels are associated with elevated NAT10 expression in clinical breast tumor samples. Together, these findings uncover a previously unrecognized role for MORC2 in regulating DNA damage-induced G2 checkpoint through NAT10-mediated acetylation and provide a potential therapeutic strategy to sensitize breast cancer cells to DNA-damaging chemotherapy and radiotherapy by targeting NAT10.

Neoadjuvant therapy and sentinel lymph node biopsy in HER2-positive breast cancer patients: results from the PEONY trial.

OBJECTIVE: The aim of the study is to evaluate the optimal timing of sentinel lymph node biopsy (SLNB) in patients with clinical negative axillary lymph nodes (ALNs) before neoadjuvant therapy (NAT) and the feasibility of SLNB substituting for ALN dissection in patients with positive ALNs who convert to node negative, for HER2-positive disease. METHODS: Patients receiving SLNB with dual tracer mapping in the PEONY trial were analyzed. RESULTS: For 80 patients with clinical negative ALNs, the node negative rate by pathology after NAT was 83.8%. SLNB was performed after NAT in 71 patients. The identification rate of sentinel lymph nodes (SLNs) was 100%. For patients with positive ALNs before NAT, the axillary pathologic complete response rate in the dual HER2 blockade arm was significantly higher than that in the single blockade arm (p = 0.002). SLNB was performed in 71 patients. The identification rate was 100% and the false-negative rate was 17.2%. The false-negative rates were 33.3%, 14.3%, and 0 when 1, 2, and more than 2 SLNs were detected. There was no false-negative case when more than 1 SLN and the clipped nodes were removed simultaneously. CONCLUSIONS: For clinical ALN negative patients, HER2-positive subtype is found to have high node negative rate by pathology and it is recommended to undergo SLNB after NAT. For patients with positive ALNs who convert to negative, the false-negative rate is high. Dual tracer mapping, more than 2 SLNs detected, more than 1 SLN identified plus the clips placed are the guarantees for lower false-negative rate.

Detection of breast cancer stem cell gene mutations in circulating free DNA during the evolution of metastases.

PURPOSE: Limited knowledge exists on the detection of breast cancer stem cell (BCSC)-related mutations in circulating free DNA (cfDNA) from patients with advanced cancers. Identification of new cancer biomarkers may allow for earlier detection of disease progression and treatment strategy modifications. METHODS: We conducted a prospective study to determine the feasibility and prognostic utility of droplet digital polymerase chain reaction (ddPCR)-based BCSC gene mutation analysis of cfDNA in patients with breast cancer. RESULTS: Detection of quantitative BCSC gene mutation in cfDNA by ddPCR mirrors disease progression and thus may represent a valuable and cost-effective measure of tumor burden. We have previously shown that hematological and neurological expressed 1-like (HN1L), ribosomal protein L39 (RPL39), and myeloid leukemia factor 2 (MLF2) are novel targets for BCSC self-renewal, and targeting these genetic alterations could be useful for personalized genomic-based therapy. CONCLUSION: BCSC mutation detection in cfDNA may have important implications for diagnosis, prognosis, and serial monitoring.

Survival and chemotherapy-related risk of second primary malignancy in breast cancer patients: a SEER-based study.

BACKGROUND: With the improvement in the survival of breast cancer, developing second primary malignancy becomes a serious health issue. The aim of this study was to explore the survival of breast cancer patients with second primary malignancy, and to evaluate the impact of chemotherapy on the risk of different cancer sites. METHOD: Obtaining data from the Surveillance, Epidemiology, and End Results database, we calculated the standardized incidence ratio (SIR) for second primary malignancy in breast cancer survivors between 2000 and 2014. Overall survival and cancer-specific survival were analyzed with Kaplan-Meier method. Then, we further conducted stratified sub-analyses according to chemotherapy. RESULTS: The overall risk of second primary cancer for all sites was significantly elevated in breast cancer patients (SIR = 1.15, 95% CI 1.14-1.16). Overall survival and cancer-specific survival of the patients with breast cancer only were significantly better than the patients with multiple primary cancers (both P < 0.001). Chemotherapy was associated with increased incidences for all sites, except lymphoma, myeloma, and chronic lymphocytic leukemia (SIR = 0.80, 95% CI 0.72-0.88; SIR = 0.85, 95% CI 0.71-1.01; SIR = 0.57, 95% CI 0.43-0.74, respectively). The risk for developing second acute myeloid leukemia after chemotherapy in breast cancer patients varied with age and latency. CONCLUSION: Female breast cancer patients showed higher incidence of second primary malignancy, which was associated with poorer prognosis. Chemotherapy benefits should be weighed against the risks of second primary malignancy.

The role and clinical significance of the CXCL17-CXCR8 (GPR35) axis in breast cancer.

BACKGROUND: Chemokine (C-X-C motif) ligand 17 (CXCL17) is the latest member of the chemokine family. However, its function in various cancer types is unknown. The G protein-coupled receptor 35 (GPR35) was identified as the receptor of CXCL17 and named recently as CXCR8. The function of the CXCL17-CXCR8 (GPR35) biological axis in cancer has not been reported. METHODS: The expression of CXCL17 and CXCR8 (GPR35) in breast cancer cell lines and a tissue microarray (TMA) was detected through western blot and immunohistochemistry (IHC). Expression data in IHC were analyzed using clinicopatholigical and survival information. RESULTS: CXCL17 and CXCR8 (GPR35) were found to be variably expressed in breast cancer cell lines. Both expressed higher in breast cancer tissue than normal adjacent tissue. Although CXCL17 can interact with CXCR8 (GPR35) in breast cancer cells in vitro, the expression correlation between these two markers in breast cancer tissue was not found to be significant. As to clinical significance, CXCR8 (GPR35) expression was found to be significantly associated with advanced histological grade and higher proliferation rate indicated by Ki-67 expression. Although CXCL17 was not found to statistically correlate with any clinicopathological characteristics, it was found to be associated with shorter overall survival and is an independent marker of poor prognosis in breast cancer. In addition, CXCL17 was found to promote proliferation and migration of breast cancer cells in vitro and in vivo. CONCLUSIONS: We investigated the role of the CXCL17-CXCR8 (GPR35) axis in breast cancer for the first time. CXCL17 is a potential oncogene and promising therapeutic target, is an independent biomarker of poor prognosis in patients with breast cancer, and can promote proliferation and migration of breast cancer cells in vitro and in vivo.

A nomogram for predicting pathological complete response in patients with human epidermal growth factor receptor 2 negative breast cancer.

BACKGROUND: The response to neoadjuvant chemotherapy has been proven to predict long-term clinical benefits for patients. Our research is to construct a nomogram to predict pathological complete response of human epidermal growth factor receptor 2 negative breast cancer patients. METHODS: We enrolled 815 patients who received neoadjuvant chemotherapy from 2003 to 2015 and divided them into a training set and a validation set. Univariate logistic regression was performed to screen for predictors and construct the nomogram; multivariate logistic regression was performed to identify independent predictors. RESULTS: After performing the univariate logistic regression analysis in the training set, tumor size, hormone receptor status, regimens of neoadjuvant chemotherapy and cycles of neoadjuvant chemotherapy were the final predictors for the construction of the nomogram. The multivariate logistic regression analysis demonstrated that T4 status, hormone receptor status and receiving regimen of paclitaxel and carboplatin were independent predictors of pathological complete response. The area under the receiver operating characteristic curve of the training set and the validation set was 0.779 and 0.701, respectively. CONCLUSIONS: We constructed and validated a nomogram to predict pathological complete response in human epidermal growth factor receptor 2 negative breast cancer patients. We also identified tumor size, hormone receptor status and paclitaxel and carboplatin regimen as independent predictors of pathological complete response.

Cisplatin plus gemcitabine versus paclitaxel plus gemcitabine as first-line therapy for metastatic triple-negative breast cancer (CBCSG006): a randomised, open-label, multicentre, phase 3 trial.

BACKGROUND: Platinum chemotherapy has a role in the treatment of metastatic triple-negative breast cancer but its full potential has probably not yet been reached. We assessed whether a cisplatin plus gemcitabine regimen was non-inferior to or superior to paclitaxel plus gemcitabine as first-line therapy for patients with metastatic triple-negative breast cancer. METHODS: For this open-label, randomised, phase 3, hybrid-designed trial undertaken at 12 institutions or hospitals in China, we included Chinese patients aged 18-70 years with previously untreated, histologically confirmed metastatic triple-negative breast cancer, and an ECOG performance status of 0-1. These patients were randomly assigned (1:1) to receive either cisplatin plus gemcitabine (cisplatin 75 mg/m(2) on day 1 and gemcitabine 1250 mg/m(2) on days 1 and 8) or paclitaxel plus gemcitabine (paclitaxel 175 mg/m(2) on day 1 and gemcitabine 1250 mg/m(2) on days 1 and 8) given intravenously every 3 weeks for a maximum of eight cycles. Randomisation was done centrally via an interactive web response system using block randomisation with a size of eight, with no stratification factors. Patients and investigator were aware of group assignments. The primary endpoint was progression-free survival and analyses were based on all patients who received at least one dose of assigned treatment. The margin used to establish non-inferiority was 1·2. If non-inferiority of cisplatin plus gemcitabine compared with paclitaxel plus gemcitabine was achieved, we would then test for superiority. The trial is registered with ClinicalTrials.gov, number NCT01287624. FINDINGS: From Jan 14, 2011, to Nov 14, 2013, 240 patients were assessed for eligibility and randomly assigned to treatment (120 in the cisplatin plus gemcitabine group and 120 in the paclitaxel plus gemcitabine group). 236 patients received at least one dose of assigned chemotherapy and were included in the modified intention-to-treat analysis (118 per group). After a median follow-up of 16·3 months (IQR 14·4-26·8) in the cisplatin plus gemcitabine group and 15·9 months (10·7-25·4) in the paclitaxel plus gemcitabine group, the hazard ratio for progression-free survival was 0·692 (95% CI 0·523-0·915; pnon-inferiority<0·0001, psuperiority=0·009, thus cisplatin plus gemcitabine was both non-inferior to and superior to paclitaxel plus gemcitabine. Median progression-free survival was 7·73 months (95% CI 6·16-9·30) in the cisplatin plus gemcitabine group and 6·47 months (5·76-7·18) in the paclitaxel plus gemcitabine group. Grade 3 or 4 adverse events that differed significantly between the two groups included nausea (eight [7%] vs one [<1%]), vomiting (13 [11%] vs one [<1%]), musculoskeletal pain (none vs ten [8%]), anaemia (39 [33%] vs six [5%]), and thrombocytopenia (38 [32%] vs three [3%]), for the cisplatin plus gemcitabine compared with the paclitaxel plus gemcitabine groups, respectively. In addition, patients in the cisplatin plus gemcitabine group had significantly fewer events of grade 1-4 alopecia (12 [10%] vs 42 [36%]) and peripheral neuropathy (27 [23%] vs 60 [51%]), but more grade 1-4 anorexia (33 [28%] vs 10 [8%]), constipation (29 [25%] vs 11 [9%]), hypomagnesaemia (27 [23%] vs five [4%]), and hypokalaemia (10 [8%] vs two [2%]). Serious drug-related adverse events were seen in three patients in the paclitaxel plus gemcitabine group (interstitial pneumonia, anaphylaxis, and severe neutropenia) and four in the cisplatin plus gemcitabine group (pathological bone fracture, thrombocytopenia with subcutaneous haemorrhage, severe anaemia, and cardiogenic syncope). There were no treatment-related deaths. INTERPRETATION: Cisplatin plus gemcitabine could be an alternative or even the preferred first-line chemotherapy strategy for patients with metastatic triple-negative breast cancer. FUNDING: Shanghai Natural Science Foundation.

Predicting Non-sentinel Lymph Node Metastasis in a Chinese Breast Cancer Population with 1-2 Positive Sentinel Nodes: Development and Assessment of a New Predictive Nomogram.

BACKGROUND: We have developed a new nomogram to predict the probability of a patient with 1-2 metastatic sentinel lymph nodes (SLNs) to present further axillary disease. METHODS: Data were collected from 480 patients who were diagnosed with 1-2 positive lymph nodes and thus underwent axillary lymph node dissection between March 2005 and June 2011. Clinical and pathological features of the patients were assessed with multivariable logistic regression. The Shanghai Cancer Center Non-SLN nomogram (SCC-NSLN) was created from the logistic regression model. This new model was subsequently applied to 481 patients from July 2011 to December 2013. The predictive accuracy of the SCC-NSLN nomogram was measured by calculating the area under the receiver operating characteristic curve (AUC). RESULTS: Based on the results of the univariate analysis, the variables that were significantly associated with the incidence of non-SLN metastasis in an SLN-positive patient included lymphovascular invasion, neural invasion, the number of positive SLNs, the number of negative SLNs, and the size of SLN metastasis (P < 0.05). Using multivariate analysis, lymphovascular invasion, the number of positive SLNs, the number of negative SLNs, and the size of SLN metastasis were identified as independent predictors of non-SLN metastasis. The SCC-NSLN nomogram was then developed using these four variables. The new model was accurate and discriminating on both the modeling and validation groups (AUC: 0.7788 vs 0.7953). The false-negative rates of the SCC-NSLN nomogram were 3.54 and 9.29 % for the predicted probability cut-off points of 10 and 15 % when applied to patients who have 1-2 positive SLNs. CONCLUSION: The SCC-NSLN nomogram could serve as an acceptable clinical tool in clinical discussions with patients. The omission of ALND might be possible if the probability of non-SLN involvement is <10 and <15 % in accordance with the acceptable risk determined by medical staff and patients.

Spermatid perinuclear RNA-binding protein promotes UBR5-mediated proteolysis of Dicer to accelerate triple-negative breast cancer progression.

Triple-negative breast cancer (TNBC) is the most lethal subtype of breast cancer with no targeted therapy. Spermatid perinuclear RNA binding protein (STRBP), a poorly characterized RNA-binding protein (RBP), has an essential role in normal spermatogenesis and sperm function, but whether and how its dysregulation contributing to cancer progression has not yet been explored. Here, we report that STRBP functions as a novel oncogene to drive TNBC progression. STRBP expression was upregulated in TNBC tissues and correlated with poor disease prognosis. Functionally, STRBP promoted TNBC cell proliferation, migration, and invasion in vitro, and enhanced xenograft tumor growth and lung colonization in mice. Mechanistically, STRBP interacted with Dicer, a core component of the microRNA biogenesis machinery, and promoted its proteasomal degradation through enhancing its interaction with E3 ubiquitin ligase UBR5. MicroRNA-sequencing analysis identified miR-200a-3p as a downstream effector of STRBP, which was regulated by Dicer and affected epithelial-mesenchymal transition. Importantly, the impaired malignant phenotypes of TNBC cells caused by STRBP depletion were largely rescued by knockdown of Dicer, and these effects were compromised by transfection of miR-200a-3p mimics. Collectively, these findings revealed a previously unrecognized oncogenic role of STRBP in TNBC progression and identified STRBP as a promising target against TNBC.

Response to anti-HER2 neoadjuvant chemotherapy in HER2-positive invasive breast cancers with different HER2 FISH patterns.

AIMS: Human epidermal growth factor receptor 2 (HER2)-positive patients with breast cancer may have different HER2/CEP17 ratios and HER2 copy numbers, with inconsistent responses to anti-HER2 neoadjuvant chemotherapy (NACT). Our study aimed to explore the relationship between different HER2 fluorescence in situ hybridisation (FISH) patterns in HER2-positive patients with breast cancer and responses to anti-HER2 NACT. METHODS: 527 patients with HER2-positive invasive breast cancer who received anti-HER2 NACT from 2015 to 2022 were included and divided into three groups by FISH results, namely group A: HER2/CEP17<2.0 and HER2 copy numbers ≥6.0, HER2 immunohistochemistry 2/3+; group B: HER2/CEP17≥2.0 and HER2 copy numbers ≥4.0 and <6.0; group C: HER2/CEP17≥2.0 and HER2 copy numbers ≥6.0. We compared clinicopathological characteristics and pathological complete response (pCR) rates of different groups. RESULTS: According to HER2 FISH results, 12 patients (2.3%, 12/527) were in group A, 40 (7.6%, 40/527) were in group B and 475 (90.1%, 475/527) were in group C. The pCR rate was the lowest in group B (5.0%), while the pCR rates in group A and group C were 33.3% and 44.4%, respectively (p (group A vs. B) =0.021, p (group C vs. B) < 0.001). Both univariate and multivariate analyses revealed that HER2 FISH pattern was correlated with pCR rate (p (group C vs. B) < 0.001, p (group C vs. B) = 0.025). CONCLUSIONS: Patients with HER2/CEP17≥2.0 and HER2 copy numbers ≥4.0 and <6.0 do not benefit to the same extent from current anti-HER2 therapies as FISH-positive patients with other patterns.

C9orf142 transcriptionally activates MTBP to drive progression and resistance to CDK4/6 inhibitor in triple-negative breast cancer.

BACKGROUND: Triple-negative breast cancer (TNBC) presents the most challenging subtype of all breast cancers because of its aggressive clinical phenotypes and absence of viable therapy targets. In order to identify effective molecular targets for treating patients with TNBC, we conducted an integration analysis of our recently published TNBC dataset of quantitative proteomics and RNA-Sequencing, and found the abnormal upregulation of chromosome 9 open reading frame 142 (C9orf142) in TNBC. However, the functional roles of C9orf142 in TNBC are unclear. METHODS: In vitro and in vivo functional experiments were performed to assess potential roles of C9orf142 in TNBC. Immunoblotting, real-time quantitative polymerase chain reaction (RT-qPCR), and immunofluorescent staining were used to investigate the expression levels of C9orf142 and its downstream molecules. The molecular mechanisms underlying C9orf142-regulated mouse double minute 2 (MDM2)-binding protein (MTBP) were determined by chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays. RESULTS: In TNBC tissues and metastatic lymph nodes, we observed that C9orf142 exhibited abnormal up-regulation, and its elevated expression was indicative of unfavorable prognosis for TNBC patients. Both in vitro and in vivo functional experiments demonstrated that C9orf142 accelerated TNBC growth and metastasis. Further mechanism exploration revealed that C9orf142 transcriptionally activated MTBP, thereby regulating its downstream MDM2/p53/p21 signaling axis and the transition of cell cycle from G1 to S phase. Functional rescue experiment demonstrated that knockdown of MTBP attenuated C9orf142-mediated tumour growth and metastasis. Furthermore, depletion of C9orf142 remarkably increased the responsiveness of TNBC cells to CDK4/6 inhibitor abemaciclib. CONCLUSIONS: Together, these findings unveil a previously unrecognized effect of C9orf142 in TNBC progression and responsiveness to CDK4/6 inhibitor, and emphasize C9orf142 as a promising intervention target for TNBC treatment.

Dynamic SUMOylation of MORC2 orchestrates chromatin remodelling and DNA repair in response to DNA damage and drives chemoresistance in breast cancer.

Rationale: SUMOylation regulates a plethora of biological processes, and its inhibitors are currently under investigation in clinical trials as anticancer agents. Thus, identifying new targets with site-specific SUMOylation and defining their biological functions will not only provide new mechanistic insights into the SUMOylation signaling but also open an avenue for developing new strategy for cancer therapy. MORC family CW-type zinc finger 2 (MORC2) is a newly identified chromatin-remodeling enzyme with an emerging role in the DNA damage response (DDR), but its regulatory mechanism remains enigmatic. Methods: In vivo and in vitro SUMOylation assays were used to determine the SUMOylation levels of MORC2. Overexpression and knockdown of SUMO-associated enzymes were used to detect their effects on MORC2 SUMOylation. The effect of dynamic MORC2 SUMOylation on the sensitivity of breast cancer cells to chemotherapeutic drugs was examined through in vitro and in vivo functional assays. Immunoprecipitation, GST pull-down, MNase, and chromatin segregation assays were used to explore the underlying mechanisms. Results: Here, we report that MORC2 is modified by small ubiquitin-like modifier 1 (SUMO1) and SUMO2/3 at lysine 767 (K767) in a SUMO-interacting motif dependent manner. MORC2 SUMOylation is induced by SUMO E3 ligase tripartite motif containing 28 (TRIM28) and reversed by deSUMOylase sentrin-specific protease 1 (SENP1). Intriguingly, SUMOylation of MORC2 is decreased at the early stage of DNA damage induced by chemotherapeutic drugs that attenuate the interaction of MORC2 with TRIM28. MORC2 deSUMOylation induces transient chromatin relaxation to enable efficient DNA repair. At the relatively late stage of DNA damage, MORC2 SUMOylation is restored, and SUMOylated MORC2 interacts with protein kinase CSK21 (casein kinase II subunit alpha), which in turn phosphorylates DNA-PKcs (DNA-dependent protein kinase catalytic subunit), thus promoting DNA repair. Notably, expression of a SUMOylation-deficient mutant MORC2 or administration of SUMO inhibitor enhances the sensitivity of breast cancer cells to DNA-damaging chemotherapeutic drugs. Conclusions: Collectively, these findings uncover a novel regulatory mechanism of MORC2 by SUMOylation and reveal the intricate dynamics of MORC2 SUMOylation important for proper DDR. We also propose a promising strategy to sensitize MORC2-driven breast tumors to chemotherapeutic drugs by inhibition of the SUMO pathway.

Protein Phosphatase 1 Subunit PPP1R14B Stabilizes STMN1 to Promote Progression and Paclitaxel Resistance in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) represents the most lethal subtype of breast cancer due to its aggressive clinical features and the lack of effective therapeutic targets. To identify novel approaches for targeting TNBC, we examined the role of protein phosphatases in TNBC progression and chemoresistance. Protein phosphatase 1 regulatory subunit 14B (PPP1R14B), a poorly defined member of the protein phosphatase 1 regulatory subunits, was aberrantly upregulated in TNBC tissues and predicted poor prognosis. PPP1R14B was degraded mainly through the ubiquitin-proteasome pathway. RPS27A recruited deubiquitinase USP9X to deubiquitinate and stabilize PPP1R14B, resulting in overexpression of PPP1R14B in TNBC tissues. Gain- and loss-of-function assays demonstrated that PPP1R14B promoted TNBC cell proliferation, colony formation, migration, invasion, and resistance to paclitaxel in vitro. PPP1R14B also induced xenograft tumor growth, lung metastasis, and paclitaxel resistance in vivo. Mechanistic investigations revealed that PPP1R14B maintained phosphorylation and stability of oncoprotein stathmin 1 (STMN1), a microtubule-destabilizing phosphoprotein critically involved in cancer progression and paclitaxel resistance, which was dependent on PP1 catalytic subunits α and γ. Importantly, the tumor-suppressive effects of PPP1R14B deficiency could be partially rescued by ectopic expression of wild-type but not phosphorylation-deficient STMN1. Moreover, PPP1R14B decreased STMN1-mediated α-tubulin acetylation, microtubule stability, and promoted cell-cycle progression, leading to resistance of TNBC cells to paclitaxel. Collectively, these findings uncover a functional and mechanistic role of PPP1R14B in TNBC progression and paclitaxel resistance, indicating PPP1R14B is a potential therapeutic target for TNBC. SIGNIFICANCE: PPP1R14B upregulation induced by RPS27A/USP9X in TNBC increases STMN1 activity, leading to cancer progression and paclitaxel resistance.

TOLLIP-mediated autophagic degradation pathway links the VCP-TMEM63A-DERL1 signaling axis to triple-negative breast cancer progression.

Triple-negative breast cancer (TNBC) is the most challenging breast cancer subtype to treat due to the lack of effective targeted therapies. Transmembrane (TMEM) proteins represent attractive drug targets for cancer therapy, but biological functions of most members of the TMEM family remain unknown. Here, we report for the first time that TMEM63A (transmembrane protein 63A), a poorly characterized TMEM protein with unknown functions in human cancer, functions as a novel oncogene to promote TNBC cell proliferation, migration, and invasion in vitro and xenograft tumor growth and lung metastasis in vivo. Mechanistic investigations revealed that TMEM63A localizes in endoplasmic reticulum (ER) and lysosome membranes, and interacts with VCP (valosin-containing protein) and its cofactor DERL1 (derlin 1). Furthermore, TMEM63A undergoes autophagy receptor TOLLIP-mediated autophagic degradation and is stabilized by VCP through blocking its lysosomal degradation. Strikingly, TMEM63A in turn stabilizes oncoprotein DERL1 through preventing TOLLIP-mediated autophagic degradation. Notably, pharmacological inhibition of VCP by CB-5083 or knockdown of DERL1 partially abolishes the oncogenic effects of TMEM63A on TNBC progression both in vitro and in vivo. Collectively, these findings uncover a previously unknown functional and mechanistic role for TMEM63A in TNBC progression and provide a new clue for targeting TMEM63A-driven TNBC tumors by using a VCP inhibitor.Abbreviations: ATG16L1, autophagy related 16 like 1; ATG5, autophagy related 5; ATP5F1B/ATP5B, ATP synthase F1 subunit beta; Baf-A1, bafilomycin A1; CALCOCO2/NDP52, calcium binding and coiled-coil domain 2; CANX, calnexin; DERL1, derlin 1; EGFR, epidermal growth factor receptor; ER, endoplasmic reticulum; ERAD, endoplasmic reticulum-associated degradation; HSPA8, heat shock protein family A (Hsp70) member 8; IP, immunoprecipitation; LAMP2A, lysosomal associated membrane protein 2; NBR1, NBR1 autophagy cargo receptor; OPTN, optineurin; RT-qPCR, reverse transcription-quantitative PCR; SQSTM1/p62, sequestosome 1; TAX1BP1, Tax1 binding protein 1; TMEM63A, transmembrane protein 63A; TNBC, triple-negative breast cancer; TOLLIP, toll interacting protein; VCP, valosin containing protein.

Destabilization of microrchidia family CW-type zinc finger 2 via the cyclin-dependent kinase 1-chaperone-mediated autophagy pathway promotes mitotic arrest and enhances cancer cellular sensitivity to microtubule-targeting agents.

BACKGROUND: Microtubule-targeing agents (MTAs), such as paclitaxel (PTX) and vincristine (VCR), kill cancer cells through activtion of the spindle assembly checkpoint (SAC) and induction of mitotic arrest, but the development of resistance poses significant clinical challenges. METHODS: Immunoblotting and RT-qPCR were used to investigate potential function and related mechanism of MORC2. Flow cytometry analyses were carried out to determine cell cycle distribution and apoptosis. The effect of MORC2 on cellular sensitivity to PTX and VCR was determined by immunoblotting, flow cytometry, and colony formation assays. Immunoprecipitation assays and immunofluorescent staining were utilized to investigate protein-protein interaction and protein co-localization. RESULTS: Here, we identified microrchidia family CW-type zinc finger 2 (MORC2), a poorly characterized oncoprotein, as a novel regulator of SAC activation, mitotic progression, and resistance of cancer cells to PTX and VCR. Mechanically, PTX and VCR activate cyclin-dependent kinase 1, which in turn induces MORC2 phosphorylation at threonine 717 (T717) and T733. Phosphorylated MORC2 enhances its interation with HSPA8 and LAMP2A, two essential components of the chaperone-mediated autophagy (CMA) mechinery, resulting in its autophagic degradation. Degradation of MORC2 during mitosis leads to SAC activation through stabilizing anaphase promoting complex/cyclosome activator protein Cdc20 and facilitating mitotic checkpoint complex assembly, thus contributing to mitotic arrest induced by PTX and VCR. Notably, knockdown of MORC2 promotes mitotic arrest induced by PTX and VCR and enhances the sensitivity of cancer cells to PTX and VCR. CONCLUSIONS: Collectively, these findings unveil a previously unrecognized function and regulatory mechanism of MORC2 in mitotic progression and resistance of cancer cells to MTAs. These results also provide a new clue for developing combined treatmentstrategy by targeting MORC2 in combination with MTAs against human cancer.

Predicting sentinel lymph node metastasis in a Chinese breast cancer population: assessment of an existing nomogram and a new predictive nomogram.

We assessed the MSKCC nomogram performance in predicting SLN metastases in a Chinese breast cancer population. A new model (the SCH nomogram) was developed with clinically relevant variables and possible advantages. Data were collected from 1,545 patients who had a successful SLN biopsy between March 2005 and November 2011. We validated the MSKCC nomogram in the modeling and validation group. Clinical and pathologic features of SLN biopsy in modeling group of 1,000 patients were assessed with multivariable logistic regression to predict the presence of SLN metastasis in breast cancer. The SCH nomogram was created from the logistic regression model and subsequently applied to 545 consecutive SLN biopsies. By multivariate analysis, age, tumor size, tumor location, tumor type, and lymphovascular invasion were identified as independent predictors of SLN metastasis. The SCH nomogram was then developed using the five variables. The new model was accurate and discriminating (with an AUC of 0.7649 in the modeling group) compared to the MSKCC nomogram (with an AUC of 0.7105 in the modeling group). The area under the ROC curve for the SCH nomogram in the validation population is 0.7587. The actual probability trends for the various deciles were comparable to the predicted probabilities. The false-negative rates of the SCH nomogram were 1.67, 3.54, and 8.20 % for the predicted probability cut-off points of 5, 10, and 15 %, respectively. Compared with the MSKCC nomogram, the SCH nomogram has a better AUC with fewer variables and has lower false-negative rates for the low-probability subgroups. The SCH nomogram could serve as a more acceptable clinical tool in preoperative discussions with patients, especially very-low-risk patients. When applied to these patients, the SCH nomogram could be used to safely avoid a SLN procedure. The nomogram should be validated in various patient populations to demonstrate its reproducibility.

Correlation between Duffy blood group phenotype and breast cancer incidence.

BACKGROUND: Different ethnicities have different distribution of Duffy blood group (DBG) phenotypes and different breast cancer morbidity. A study in our lab demonstrated that Duffy antigen/receptor for chemokines (DARC, also known as DBGP, the Duffy protein phenotype), led to the inhibition of tumorigenesis. Therefore, we tested the hypothesis that DBGP is correlated with breast cancer occurrence. METHODS: DBGP proteins were examined by indirect antiglobulin testing with anti-FYa and anti-FYb antibodies. The phenotypes were classified into four groups according to the agglutination reactions: FYa + FYb+, FYa + FYb-, FYa-FYb + and FYa-FYb-. The phenotypes and pathological diagnosis of consecutively hospitalized female patients (n = 5,022) suffering from breast cancer at the Shanghai Cancer Hospital and Henan Province Cancer Hospital were investigated. The relationships between DBGP expression with breast cancer occurrence, axillary lymph status, histological subtype, tumor size pathological grade and overall survival were analyzed. RESULTS: The incidence of breast cancer was significantly different between FYa + FYb + (29.8%), FYa + FYb- (33.2%), FYa-FYb + (45.6%) and FYa-FYb- (59.1%; P = 0.001). Significant different numbers of breast cancer patients had metastases to the axillary lymph nodes in the FYa + FYb + group (25.1%), FYa + FYb- (36.9%), FYa-FYb + (41.0%) and FYa-FYb- (50.0%, (P = 0.005). There was a statistical significance (p = 0.022) of the overall survival difference between patients with difference phenotypes. No significant difference was observed in cancer size (t-test, p > 0.05), histological cancer type (Fisher's exact test, p > 0.05) or histological grade (Fisher's exact test, p > 0.05) between every each DBGP group. CONCLUSIONS: DBGP is correlated with breast cancer incidence and axillary lymph node metastasis and overall survival. Further investigations are required to determine the underlying mechanism of Duffy blood group phenotype on breast cancer risk.

[Therapeutic effect of ovarian intra-arterial infusion of GE7-delivery system-mediated HSVl-tk/ganciclovir gene therapy in a rat model of malignant ovarian tumor].

OBJECTIVE: To observe the gene expression of herpes simplex virus type 1 thymidine kinase (HSVl-tk) in rat malignant ovarian tumor tissues and the therapeutic effect of ganciclovior (GCV) after intra-arterial infusion of HSVl-tk gene therapy mediated by GE7-delivery system. METHODS: A GE7-polylysine/pCMV-HSV1-tk/polylysine-HA20 4-element complex was constructed. Eighteen rats with DMBA-induced ovarian tumor were divided into 3 groups as Atk, ANS and Vtk groups. The 4-element complex GE7-polylysine/pCMV-HSV1-tk/polylysine-HA20 was injected via the ovarian artery into the rats of Atk group, saline buffer was injected in the ANS groups, and the 4-element complex was injected via the tail vein into the rats of Vtk group. All rats received intraperitoneal injection of GCV in a dose of 50 mg/kg daily for 10 days. The rats were sacrificed 3 days after the final dose of GCV, and the tumor weight was measured and tumor growth inhibition rate was calculated. Flow cytometry was used to assess the cell cycle and apoptosis. RESULTS: The tumor weight in the rats of Atk group was (4.77 ± 2.31) g, significantly lower than that of ANS group [(14.66 ± 6.26) g, P < 0.01] and Vtk group [(17.53 ± 7.19) g, P < 0.01]. The tumor growth inhibition rate of the Atk group was 67.5%, while that of Vtk group was -19.6%. The flow cytometry showed that S-phase tumor cells in the Atk group were (54.32 ± 9.65)%, significantly higher than that in the ANS (27.43 ± 9.22)% and (30.16 ± 11.57)% in the Vtk group (both P < 0.01). The tumor cell apoptosis rate in the Atk group was (39.15 ± 12.16)%, significantly higher than that in the ANS group [(11.86 ± 5.28)%, P < 0.01] and Vtk group [(14.32 ± 6.43)%, P < 0.01]. CONCLUSION: HSV1-tk/GCV gene therapy system mediated by GE7 non-viral delivery system via ovarian arterial infusion effectively causes cell cycle arrest at S phase and enhances cell apoptosis, therefore, exerts an inhibitory effect on tumor growth.

[Correlation of polymorphism rs1563828 in MDM4 gene with breast cancer risk and onset age].

OBJECTIVE: To explore effect of polymorphism rs1563828 (C > T) in human murine double minute 4 gene (MDM4) on genetic susceptibility for early-onset breast cancer and potential association with age of onset of breast cancer. METHODS: One hundred and twenty-four early-onset breast cancer patients (age ≤ 35 years at time of diagnosis) from independent families admitted from January 2006 to June 2010 and 101 age-matched healthy control subjects were analyzed. Genotype analysis was conducted by polymerase chain reaction and then MALDI-TOF-MS assay. Association of genotype distribution and breast cancer risk was evaluated by χ(2) test. The odd-ratios (OR) and 95% confidence intervals (CI) were calculated by unconditional Logistic regression model. The t test was used to compare the age and demographic differences among groups. RESULTS: The frequency of rs1563828 polymorphism genotypes in control group were CC 43.6% (44/101), CT 42.6% (43/101), TT 13.9% (14/101), and in case group were 42.7% (53/124), 46.0% (57/124), 11.3% (14/124), respectively. No significant difference (χ(2) = 0.449, P = 0.799) was reached by χ(2) test. rs1563828CT or TT genotype does not confer a significantly increased risk for breast cancer compared with CC genotype after adjusting for age, menarche in Logistic regression analysis (OR = 1.024, 95%CI: 0.581 - 1.806, P = 0.934). TT carriers were observed to develop breast cancer earlier than CC/CT carriers [(30 ± 4) years vs. (32 ± 3) years, P = 0.028]. CONCLUSIONS: The rs1563828(C > T) polymorphism in MDM4 gene may not confer risk to breast cancer, especially for early-onset breast cancer patients. Homozygous TT of rs1563828 is associated with younger age to develop breast cancer.

[Correlation of miR-195 with invasiveness and prognosis of breast cancer].

OBJECTIVE: To explore the potential role of miR-195 on invasiveness and prognosis of breast cancer. METHODS: The RNA in formalin-fixed paraffin embedded (FFPE) of 88 breast cancer patients with primary tumors was extracted, and miR-195 levels were quantified by quantitative real-time polymerase chain reaction (real-time PCR). The relationship of miR-195 levels and clinicopathological variables were assessed by Mann Whitney-U test. Recurrence-free survival and overall survival curves were derived from Kaplan-Meier estimates and the curves were compared by Log-rank tests. Cox regression analysis was used for multivariate analysis. All statistical tests were two-sided. RESULTS: The levels of miR-195 in the breast cancer with histological high grade, tumor size of T3-4, lymph nodal involvement or vessel invasion were significantly down-regulated, compared with those of patients with histological low grade (Z = -2.271, P = 0.023), tumor size of T1-2 (Z = -2.687, P = 0.007), no lymph node metastasis (Z = -1.967, P = 0.049) and vessel invasion (Z = -2.432, P = 0.015). In addition, no statistically significant difference (P > 0.05) was identified between miR-195 levels and hormone receptors status, HER-2 expression, TNM stage, tumor types, recurrence and menstrual status. When considering 2(-ΔCt) = 0.270 (median level) as cut-off value, Kaplan-Meier survival analysis indicated that patients with high miR-195 level showed a positive association towards a longer survival, either recurrence-free survival (χ(2) = 5.985, P = 0.014) or overall survival (χ(2) = 30.05, P = 0.000). In a multivariate analysis, miR-195 expression on FFPE correlated significantly with outcomes of breast cancer (HR = 0.040, 95%CI: 0.009 - 0.179, P = 0.000) and was independent of other prognostic factors. CONCLUSIONS: It suggests that miR-195 expression on FFPE is inversely correlated with histological high grade, bigger tumor size, lymph node involvement, vessel invasion. Furthermore, as independent prognostic factor, low miR-195 significantly contributes to poor outcomes of breast cancer.