Role of RPL39 in Metaplastic Breast Cancer

Proteomic profiling of urinary extracellular vesicles differentiates breast cancer patients from healthy women

Urinary extracellular vesicles (uEVs) reflect the biological conditions of the producing cells. The protein profiling of uEVs allow us to better understand cancer progression in several cancers such as bladder cancer, prostate cancer and kidney cancer but has not been reported in breast cancer. We have, herein, aimed at quantifying the concentration and at generating the proteomic profile of uEVs in patients with breast cancer (BC) as compared to that of healthy controls (CT). Urine samples were collected from 29 CT and 47 patients with BC. uEVs were isolated by using differential ultracentrifugation, and were then characterized by Western blotting and transmission electron microscopy. Moreover, a nanoparticle tracking analysis was used in order to measure the concentration and the size distribution of urine particles and uEVs. The proteomic profiling of the uEVs was facilitated through LC-MS/MS. The uEV concentration was not significantly different between the assessed groups. The undertaken proteomic analysis revealed 15,473 and 11,278 proteins in the BC patients' group and the CT group, respectively. Furthermore, a heat map analysis revealed a differential protein expression, while a principal component analysis highlighted two clusters. The volcano plot indicated 259 differentially expressed proteins (DEPs; 155 up- and 104 down-regulated proteins) in patients with BC compared with CT. The up-regulated proteins from BC-derived uEVs were enriched in pathways related to cancer progression (i.e., cell proliferation, cell survival, cell cycle, cell migration, carbohydrate metabolism, and angiogenesis). Moreover, we verified the expression of the upregulated DEPs using UALCAN for web-based validation. Remarkably, the results indicated that 6 of 155 up-regulated proteins (POSTN, ATAD2, BCAS4, GSK3β, HK1, and Ki-67) were overexpressed in BC compared with normal samples. Since these six proteins often act as markers of cell proliferation and progression, they may be potential biomarkers for BC screening and diagnosis. However, this requires validation in larger cohorts.

Potential Candidate Genes for Therapeutic Targeting in Chronic Myeloid Leukemia: A Pilot Study

BACKGROUND

Chronic myeloid leukemia (CML) is a prevalent hematological malignancy known for the presence of the Philadelphia chromosome and activation of the BCR-Abl kinase activity. Although tyrosine kinase inhibitors are widely used as the standard treatment, resistance remains a concern among certain patients. This study aimed to investigate the gene expression profile of a group of CML patients in comparison to a control group in order to identify novel candidate genes associated with the disease.

METHODS

Whole transcriptome sequencing was performed, and gene expression levels were validated using quantitative real-time PCR. Additionally, single nucleotide and insertion/deletion variants were analyzed in the selected candidate genes among 10 CML patients and 4 healthy control subjects.

RESULTS

Analysis revealed a set of differentially expressed genes, whose up- or downregulation was further confirmed by qRT-PCR. Among the upregulated genes in the patient group were ribosomal protein like (RPL) members, specifically RPL9, RPL34, RPL36A, and RPL39, while downregulation was observed in CCDC170, LDB1, and SBF1 compared to the healthy subjects. Furthermore, gene variant studies identified novel genetic changes in these candidate genes, suggesting potential clinical significance in CML.

CONCLUSIONS

This study highlights RPL9, RPL34, RPL36A, RPL39, CCDC170, LDB1, and SBF1 as potential targets in CML. Additionally, it underscores the importance of investigating these genes and their variants in larger cohort studies to assess their clinical significance in CML patients.

RPL27 contributes to colorectal cancer proliferation and stemness via PLK1 signaling

Although expression of ribosomal protein L27 (RPL27) is upregulated in clinical colorectal cancer (CRC) tissue, to the best of our knowledge, the oncogenic role of RPL27 has not yet been defined. The present study aimed to investigate whether targeting RPL27 could alter CRC progression and determine whether RPL27 gains an extra‑ribosomal function during CRC development. Human CRC cell lines HCT116 and HT29 were transfected with RPL27‑specific small interfering RNA and proliferation was assessed in vitro and in vivo using proliferation assays, fluorescence‑activated cell sorting (FACS) and a xenograft mouse model. Furthermore, RNA sequencing, bioinformatic analysis and western blotting were conducted to explore the underlying mechanisms responsible for RPL27 silencing‑induced CRC phenotypical changes. Inhibiting RPL27 expression suppressed CRC cell proliferation and cell cycle progression and induced apoptotic cell death. Targeting RPL27 significantly inhibited growth of human CRC xenografts in nude mice. Notably, polo‑like kinase 1 (PLK1), which serves an important role in mitotic cell cycle progression and stemness, was downregulated in both HCT116 and HT29 cells following RPL27 silencing. RPL27 silencing reduced the levels of PLK1 protein and G2/M‑associated regulators such as phosphorylated cell division cycle 25C, CDK1 and cyclin B1. Silencing of RPL27 reduced the migration and invasion abilities and sphere‑forming capacity of the parental CRC cell population. In terms of phenotypical changes in cancer stem cells (CSCs), RPL27 silencing suppressed the sphere‑forming capacity of the isolated CD133+ CSC population, which was accompanied by decreased CD133 and PLK1 levels. Taken together, these findings indicated that RPL27 contributed to the promotion of CRC proliferation and stemness via PLK1 signaling and RPL27 may be a useful target in a next‑generation therapeutic strategy for both primary CRC treatment and metastasis prevention.

The conundrum of metaplastic breast cancer: a single Egyptian institution retrospective 10-year experience (2011-2020)

BACKGROUND

Metaplastic breast cancer (MetBC) still represents a conundrum owing to its peculiar histogenesis and molecular drivers that render it extremely resistant to standard chemotherapy with ultimate dismal survival.

AIM

Describe the Egyptian National Cancer Institute's (NCI-E) experience with MetBC regarding its clinicopathologic features, treatment, and survival outcomes.

PATIENTS AND METHODS

Between 2011 and 2020, all MetBC patients presented to NCI-E were retrospectively evaluated. Original clinicopathologic data, therapeutic modalities, pathologic response to neoadjuvant chemotherapy (NACT), recurrence, and date of last follow-up/death were obtained from archived charts.

RESULTS

A cohort of 135 females, the median age was 52 years, and median follow-up period was 40 months (range: 2.6-130.8). Two-thirds were triple negative (TN). Squamous carcinoma was prevalent in 74.8% followed by carcinoma with osseous/chondroid differentiation, spindle cell, and low-grade adenosquamous carcinoma encountered in 13.3, 7.4, and 4.5%, respectively. Modified radical mastectomy was done in 59.3%, and positive nodes (pN+) were depicted in 37.7%. Median Ki-67 was 45% (range: 10-88); grade III and lymphovascular invasion (LVI) were observed in 83.7 and 43.7%, respectively. Stage II was the most common (49%), whereas initial stage IV was encountered in 8.1%. Anthracyclines/taxane combinations were rampant in adjuvant/neoadjuvant settings. The latter was employed in 41 patients, with only 3 cases (7.3%) achieving pathologic complete response (pCR), while moderate/significant residual tumor burden was found in 83%. The 5-year DFS and OS were 56.4 and 57.6%, respectively. Spindle cell carcinoma showed the worst survival parameters in univariate analysis. On the multivariate level, higher tumor stage (pT3 & 4), Ki-67 ≥ 45%, and TN subtype were independent variables for worse DFS and OS; age ≥ 52 years and the presence of LVI were independent features for worse DFS, whereas pN+ was an independent parameter for worse OS.

CONCLUSIONS

This study further solidifies the dreadful response of MetBC to conventional chemotherapy regimens employed in common non-metaplastic pathologies. A radical shift in treatment standards tailored to combat the molecular landscape of this distinctive tumor is urgently needed. Immunotherapy and molecularly targeted agents demonstrated promising results in phase I and II trials with hopeful sooner implementation in phase III studies.

Targeting Nitric Oxide: Say NO to Metastasis

Utilizing targeted therapies capable of reducing cancer metastasis, targeting chemoresistant and self-renewing cancer stem cells, and augmenting the efficacy of systemic chemo/radiotherapies is vital to minimize cancer-associated mortality. Targeting nitric oxide synthase (NOS), a protein within the tumor microenvironment, has gained interest as a promising therapeutic strategy to reduce metastatic capacity and augment the efficacy of chemo/radiotherapies in various solid malignancies. Our review highlights the influence of nitric oxide (NO) in tumor progression and cancer metastasis, as well as promising preclinical studies that evaluated NOS inhibitors as anticancer therapies. Lastly, we highlight the prospects and outstanding challenges of using NOS inhibitors in the clinical setting.

The mixed subtype has a worse prognosis than other histological subtypes: a retrospective analysis of 217 patients with metaplastic breast cancer

OBJECTIVE

Metaplastic breast cancer (MpBC) is an aggressive subtype of all breast cancer. We aimed to investigate the clinicopathological features, treatments and prognoses of MpBC patients.

METHODS

We collected the data from MpBC patients diagnosed at Tianjin Medical University Cancer Hospital from 2010 to 2017. Kaplan Meier curves and Cox regression model were used to evaluating clinical outcomes and prognostic factors. After removing baseline differences by propensity score matching (PSM), we analyzed the prognosis between MpBC patients and invasive ductal carcinomas of no special type (IDC-NST) patients.

RESULTS

A total of 217 MpBC patients were subsumed. Of all histological subtypes, 45.1% were mixed subtypes, followed by with mesenchymal differentiation (27.2%), pure squamous (15.2%) and pure spindle (12.4%) subtypes. 69.6% of MpBC were triple-negative, 25.3% and 6.5% were HR-positive and HER2-positive. MpBC patients had worse survival compared to IDC-NST patients, with 5-year RFS of 73.8 and 83.6% (HR = 1.177 95%CI (1.171-2.676) P = 0.0068), and 5-year BCSS of 79.0% and 89.7% (HR = 2.187 95%CI (1.357-3.523) P = 0.0013). In the multivariate COX model, AJCC stage, mixed subtype and chemotherapy were independent prognostic factors. Mixed MpBC is more aggressive than pure and with heterologous mesenchymal differentiation subtypes. And whether squamous or spindle MpBC, mixed forms have shorter outcomes than pure forms.

CONCLUSIONS

MpBCs are associated with poorer prognoses than IDC-NSTs. They are heterogeneous with different clinicopathological features and clinical outcomes between histological subtypes. Pure and with heterologous mesenchymal differentiation subtypes have more survival benefits than the mixed subtype.

Krüppel-like factor 7 influences translation and pathways involved in ribosomal biogenesis in breast cancer

Background

Ribosomal biogenesis and ribosomal proteins have attracted attention in the context of tumor biology in recent years. Instead of being mere translational machineries, ribosomes might play an active role in tumor initiation and progression. Despite its importance, regulation of ribosomal biogenesis is still not completely understood.

Methods

Using Gene Set Enrichment Analysis of RNA sequencing and proteomical mass spectrometry data in breast cancer cells expressing Krüppel-like factor 7 (KLF7), we identified processes altered by this transcription factor. In silico analyses of a cohort of breast cancer patients in The Cancer Genome Atlas confirmed our finding. We further verified the role of KLF7 the identified ribosomal processes in in vitro assays of mammary carcinoma cell lines and analyses of breast cancer patients’ tissue slices.

Results

We identified the transcription factor Krüppel-like factor 7 (KLF7) as a regulator of ribosomal biogenesis and translation in breast cancer cells and tissue. Highly significant overlapping processes related to ribosomal biogenesis were identified in proteomics and transcriptomics data and confirmed in patients’ breast cancer RNA Seq data. Further, nucleoli, the sites of ribosomal biogenesis, were morphologically altered and quantitatively increased in KLF7-expressing cells. Pre-rRNA processing was identified as one potential process affected by KLF7. In addition, an increase in global translation independent from proliferation and transcription was observed upon exogenous KLF7 expression in vitro. Importantly, in a cohort of breast cancer patients, KLF7-expression levels correlated with aggressiveness of the intrinsic breast cancer subtype and tumor grading. Moreover, KLF7 correlated with nucleolar characteristics in human breast tumor tissue, indicating a role for KLF7 in ribosomal biogenesis.

Conclusion

In mammary carcinoma, KLF7 is involved in ribosomal biogenesis. Alterations of ribosomal biogenesis has far reaching quantitative and qualitative implications for the proteome of the cancer cells. This might influence the aggressiveness of cancer cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-022-01562-8.

Identification and validation of a 17-gene signature to improve the survival prediction of gliomas

Gliomas are one of the most frequent types of nervous system tumours and have significant morbidity and mortality rates. As a result, it is critical to fully comprehend the molecular mechanism of glioma to predict prognosis and target gene therapy. The goal of this research was to discover the hub genes of glioma and investigate their prognostic and diagnostic usefulness. In this study, we collected mRNA expression profiles and clinical information from glioma patients in the TCGA, GTEx, GSE68848, and GSE4920 databases. WGCNA and differential expression analysis identified 170 DEGs in the collected datasets. GO and KEGG pathway analyses revealed that DEGs were mainly enriched in gliogenesis and extracellular matrix. LASSO was performed to construct prognostic signatures in the TCGA cohort, and 17 genes were used to build risk models and were validated in the CGGA database. The ROC curve confirmed the accuracy of the prognostic signature. Univariate and multivariate Cox regression analyses showed that all independent risk factors for glioma except gender. Next, we performed ssGSEA to demonstrate a high correlation between risk score and immunity. Subsequently, 7 hub genes were identified by the PPI network and found to have great drug targeting potential. Finally, RPL39, as one of the hub genes, was found to be closely related to the prognosis of glioma patients. Knockdown of RPL39 in vitro significantly inhibited the proliferation and migration of glioma cells, whereas overexpression of RPL39 had the opposite effect. And we found that knockdown of RPL39 inhibited the polarization and infiltration of M2 phenotype macrophages. In conclusion, our new prognosis-related model provides more potential therapeutic strategies for glioma patients.

RNA Editing Enzyme ADAR1 Regulates METTL3 in an Editing Dependent Manner to Promote Breast Cancer Progression via METTL3/ARHGAP5/YTHDF1 Axis

A-to-I RNA editing and m⁶A modification are two of the most prevalent types of RNA modifications controlling gene expression in mammals and play very important roles in tumorigenesis and tumor progression. However, the functional roles and correlations of these two RNA modifications remain to be further investigated in cancer. Herein, we show that ADAR1, an A-to-I RNA-editing enzyme, interacts with METTL3 and increases its protein level to promote the proliferation, migration and invasion of breast cancer cells through a mechanism connecting ADAR1, METTL3 and YTHDF1. We show that both ADAR1 and METTL3 are upregulated in breast cancer samples, and ADAR1 positively correlates with METTL3; ADAR1 edits METTL3 mRNA and changes its binding site to miR532-5p, leading to increased METTL3 protein, which further targets ARHGAP5, recognized by YTHDF1. Additionally, we show that loss of ADAR1 significantly inhibits breast cancer growth in vivo. Collectively, our findings identify the ADAR1–METTL3 axis as a novel, important pathway that connects A-to-I editing and m⁶A RNA modifications during breast cancer progression.

Acylglycerol kinase promotes ovarian cancer progression and regulates mitochondria function by interacting with ribosomal protein L39

Background

Epithelial ovarian cancer (EOC) is the leading cause of deaths among patients with gynecologic malignancies. In recent years, cancer stem cells (CSCs) have attracted great attention, which have been regarded as new biomarkers and targets in cancer diagnoses as well as therapies. However, therapeutic failure caused by chemotherapy resistance in late-stage EOC occurs frequently. The 5-year survival rate of patients with EOC remains at about 30%.

Methods

In this study, the expression of acylglycerol kinase (AGK) was analyzed among patients with EOC. The effect of AGK on EOC cell proliferation and tumorigenicity was studied using Western blotting, flow cytometry, EdU assay and in vivo xenotransplantation assays. Furthermore, AGK induced CSC-like properties and was resistant to cisplatin chemotherapy in the EOC cells, which were investigated through sphere formation assays and the in vivo model of chemoresistance. Finally, the relationship between AGK and RPL39 (Ribosomal protein L39) in mitochondria as well as their effect on the mitochondrial function was analyzed through methods including transmission electron microscopy, microarray, biotin identification and immunoprecipitation.

Results

AGK showed a markedly upregulated expression in EOC, which was significantly associated with the poor survival of patients with EOC, the expression of AGK-promoted EOC cell proliferation and tumorigenicity. AGK also induced CSC-like properties in the EOC cells and was resistant to cisplatin chemotherapy. Furthermore, the results indicated that AGK not only maintained mitochondrial cristae morphogenesis, but also increased the production of reactive oxygen species and Δψm of EOC cells in a kinase-independent manner. Finally, our results revealed that AGK played its biological function by directly interacting with RPL39.

Conclusions

We demonstrated that AGK was a novel CSC biomarker for EOC, which the stemness of EOC was promoted and chemotherapy resistance was developed through physical as well as functional interaction with RPL39.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02448-5.

MQuad enables clonal substructure discovery using single cell mitochondrial variants

Mitochondrial mutations are increasingly recognised as informative endogenous genetic markers that can be used to reconstruct cellular clonal structure using single-cell RNA or DNA sequencing data. However, identifying informative mtDNA variants in noisy and sparse single-cell sequencing data is still challenging with few computation methods available. Here we present an open source computational tool MQuad that accurately calls clonally informative mtDNA variants in a population of single cells, and an analysis suite for complete clonality inference, based on single cell RNA, DNA or ATAC sequencing data. Through a variety of simulated and experimental single cell sequencing data, we showed that MQuad can identify mitochondrial variants with both high sensitivity and specificity, outperforming existing methods by a large extent. Furthermore, we demonstrate its wide applicability in different single cell sequencing protocols, particularly in complementing single-nucleotide and copy-number variations to extract finer clonal resolution.

Mitochondrial variants are informative endogenous barcodes for clonal substructure. Here, the authors developed a computational method MQuad to effectively detect these clonal informed mtDNA variants from single-cell RNA, DNA or ATAC sequencing data.

The Effect of Post-Mastectomy Radiotherapy in Patients With Metaplastic Breast Cancer: A Propensity Score-Matched Analysis of the SEER Database

Background

Metaplastic breast cancer (MBC) is a rare tumor with aggressive biological behavior. This study aimed to evaluate the efficacy of post-mastectomy radiotherapy (PMRT) on patients with low-risk (T1N0M0), intermediate-risk (T1-2N1M0 and T3N0M0), and high-risk (T1-4N2-3M0 and T4N0-1M0) MBC via propensity-score matching (PSM).

Methods

We analyzed information from the Surveillance, Epidemiology, and End Results (SEER) public-use database from 1975 to 2016 for MBC incidence trends and compared overall survival (OS) and breast cancer-specific survival (BCSS) between groups of MBC women diagnosed from 2001 to 2016 using Kaplan–Meier analysis and the multivariate Cox proportional model. PSM was used to make 1:1 case–control matching.

Results

Joinpoint analyses identified 1984 and 2003 as the inflection points among 4,672 patients. 1,588 (42.4%) of the 3,748 patients diagnosed with MBC between 2001 and 2016 received PMRT. According to multivariate analyses, PMRT provided better OS (p < 0.001) and BCSS (p < 0.001) before PSM, and better prognosis after PSM (n = 2528) for patients receiving PMRT (n = 1264) compared to those without PMRT (OS, p < 0.001 and BCSS, p < 0.001). When stratifying the case–control matching patients into low-risk, intermediate-risk, and high-risk groups, PMRT could improve BCSS compared with that in non-PMRT patients in the high-risk groups; it also improved OS in both the intermediate- and high-risk groups.

Conclusions

Per findings of the PSM analysis, PMRT could provide better BCSS in high-risk groups, and better OS in intermediate- and high-risk groups.

Utility of Oncotype DX score in clinical management for T1 estrogen receptor positive, HER2 negative, and lymph node negative breast cancer

BACKGROUND

The management of estrogen receptor positive (ER+)/HER2- and lymph node (LN) negative breast cancers can be influenced by Oncotype DX recurrence score (RS) in the USA. However, the benefit of RS in T1 tumors (≤ 1 cm) is not clear.

METHODS

We retrieved 199 T1 ER+/HER2-/LN- breast cancer diagnosed between 1993 and 2016 that had undergone RS testing. The median follow-up time was 51 months. We examined the disease-free survival (DFS) and distant metastasis and their association with RS and other clinicopathologic features.

RESULTS

Of the 199 cases, 40 were T1a (≤ 0.5 cm) and 159 were T1b (> 0.5 cm to 1 cm) tumors. In the 40 T1a tumors, 11 would benefit from chemotherapy by the TAILORx study results. Of these T1a tumors, 36 were Nottingham grade 1/2, 3 were grade 3, and 1 was microinvasive carcinoma; 2 (5%) had local recurrence and 1 (2.5%) had distant metastasis to the bone. The only patient with T1a tumor (Nottingham grade 3, RS = 42) and distant metastasis to bone had received adjuvant chemotherapy. In the 159 T1b tumors, 25 would benefit chemotherapy by the TAILORx results. Of the T1b tumors, 149 were Nottingham grade 1/2 and 10 were grade 3. Nine (5.7%) had local recurrence and 2 (1.3%) had distant metastasis to bone and mediastinum, respectively. The two T1b tumors with distant metastasis had a RS 20 and Nottingham grade 2, and RS 27 and Nottingham grade 3, respectively. Both patients received adjuvant chemotherapy. In multivariate analysis of the entire cohort (T1a and T1b tumors), Nottingham tumor grade and receiving chemotherapy were significantly associated with DFS. In univariate analysis of the entire cohort, Nottingham tumor grade, receiving adjuvant chemotherapy, and RS were significantly associated with distant metastasis.

CONCLUSION

This study demonstrates that the metastatic rate of T1a and T1b ER+/HER2-/LN- breast cancer is very low. Patients with low grade (1 or 2), T1a ER+/HER2-/LN- breast cancer may not need RS for treatment decision-making; however, in patients with high-grade T1a or T1b ER+/HER2-/LN- breast cancer, RS analysis should be strongly considered.

A phase 1/2 clinical trial of the nitric oxide synthase inhibitor L-NMMA and taxane for treating chemoresistant triple-negative breast cancer

[Figure: see text].

Deletion of ribosomal paralogs Rpl39 and Rpl39l compromises cell proliferation via protein synthesis and mitochondrial activity

Accumulating evidences suggest that the composition and functional roles of ribosomes are heterogeneous in cells, partly due to the temporal-spatial expression of paralogous ribosomal proteins (RPs), of which functional relationships remain largely unexplored. In mouse, the X chromosome-linked RPL39 and its male germline specific paralog RPL39L are thought to express mutually exclusively due to the meiotic sex chromosome inactivation, hinders the understanding of their functional relationships. In the present study, we investigated the expression and functional relations of Rpl39 and Rpl39l in a proliferative mouse cell line, in which both genes are expressed simultaneously, with the expression level of Rpl39 higher than that of Rpl39l. Disruption of Rpl39 via CRISPR/Cas9 method caused decreased cell proliferation, nascent protein synthesis and altered mitochondrial functions, whereas double mutations of Rpl39 and Rpl39l augmented these phenotypes, suggesting that both RPs contribute to the cellular physiology. Consistently, overexpression of Rpl39, Rpl39l or an alanine mutant of RPL39, rescued cell proliferation similarly in Rpl39^-/-::Rpl39l^-/- dual gene null cells. Deletion of Rpl39l induced compensatory expression of Rpl39, rendering the deleterious effects of Rpl39l mutation. Supporting this, Rpl39l mutation was more detrimental to cells under a low serum condition, under which the compensatory expression of Rpl39 was inhibited. Moreover, the low serum condition induced expression of both genes, suggesting that they possess stress responsive roles. Taken together, these data indicate that both RPL39 and RPL39L influence cell proliferation via protein synthesis and mitochondrial functions, suggesting a link between protein translation and cellular metabolism through these ribosomal protein paralogs.

Downregulated ribosomal protein L39 inhibits trophoblast cell migration and invasion by targeting E-cadherin in the placenta of patients with preeclampsia

Early-onset preeclampsia (PE) is a pregnancy complication that can lead to severe adverse maternal and fetal outcomes. However, the mechanisms underlying the development of early-onset PE are not fully understood. Ribosomal protein L39 (RPL39) is a member of the S39E family of ribosomal proteins that plays an important role in stem cell self-renewal, cancer metastasis, and chemoresistance. In this study, we aimed to explore the potential function of RPL39 in placental trophoblast cells. We analyzed the expression of RPL39 in early-onset PE and normal placental tissues using real-time PCR, western blot analysis, and immunohistochemistry. The results showed that RPL39 was markedly downregulated in early-onset PE placental tissues. RPL39 knockdown inhibited trophoblast cell proliferation, migration, and invasion, as well as placental explant outgrowth. Flow cytometry analysis suggested that knockdown of RPL39 resulted in cell cycle arrest at the G0/G1 phase, but had no significant effect on cell apoptosis. We also found that RPL39 knockdown could alter cell morphology. We then measured the expression of the epithelial cell marker E-cadherin following knockdown of RPL39 in Bewo and HTR8/SVneo cells. RPL39 knockdown increased the expression of E-cadherin. Furthermore, E-cadherin expression was upregulated in placental explant outgrowth tissues transfected with RPL39 small interfering RNA. In conclusion, RPL39 plays an essential role in proliferation, invasion, and migration of trophoblast cells by targeting E-cadherin. Our findings provide novel insight into the mechanisms underlying the occurrence of early-onset PE.

Durable Response to PD1 Inhibitor Pembrolizumab in a Metastatic, Metaplastic Breast Cancer

Metaplastic breast cancer (MBC) is a rare and aggressive subtype of breast cancer. Tumor characteristics typically feature estrogen receptor, progesterone receptor, and HER2-negative, triple-negative breast cancer (TNBC), with a poorer prognosis relative to pure invasive ductal or lobular disease. Resistance to chemotherapy often leads to local recurrence and distant metastasis. Genomic profiling has identified multiple molecular abnormalities that may translate to targetable therapies in MBC. These tumors are known to display higher PD-L1 expressivity than other subtypes of breast cancer, and disease control with pembrolizumab and chemotherapy has been documented. We identify a patient with metastatic, metaplastic TNBC, with mesenchymal components and osseous differentiation, who completed 2 years of pembrolizumab treatment and has remained without evidence of disease after 32 months of observation, while maintaining good quality of life. Future efforts should focus on immunotherapy response with respect to the various subtypes of MBC, and treatment should continue to be incorporated in clinical trials to maximize disease response.

Role of Nitric Oxide in Gene Expression Regulation during Cancer: Epigenetic Modifications and Non-Coding RNAs

Nitric oxide (NO) has been identified and described as a dual mediator in cancer according to dose-, time- and compartment-dependent NO generation. The present review addresses the different epigenetic mechanisms, such as histone modifications and non-coding RNAs (ncRNAs), miRNA and lncRNA, which regulate directly or indirectly nitric oxide synthase (NOS) expression and NO production, impacting all hallmarks of the oncogenic process. Among lncRNA, HEIH and UCA1 develop their oncogenic functions by inhibiting their target miRNAs and consequently reversing the inhibition of NOS and promoting tumor proliferation. The connection between miRNAs and NO is also involved in two important features in cancer, such as the tumor microenvironment that includes key cellular components such as tumor-associated macrophages (TAMs), cancer associated fibroblasts (CAFs) and cancer stem cells (CSCs).

Metaplastic breast cancer: Treatment and prognosis by molecular subtype

BACKGROUND

Metaplastic breast cancer (MBC) is a rare and aggressive subtype of breast. However, the effect of molecular subtype on treatment and prognosis of MBC remains unclear.

PATIENTS AND METHODS

The Surveillance, Epidemiology, and End Results database was used to analyze patients with MBC between 2010 and 2016. Molecular subtype was stratified to TN group (ER and PR-/HER2-), HER2 group (ER and PR-/HER2+, ER/PR+ and HER2+), and HR group (ER/PR+ and HER2-). The breast cancer-specific survival (BCSS) differences were estimated using multivariate Cox regression model and Kaplan-Meier curves.

RESULTS

We included 1665 patients with median follow-up time of 27 months (range 0-83 months). 1154 (69.3%), 65 (3.9%), and 446 (26.8%) patients presented in TN group, HER2 group, and HR group, respectively. On multivariate Cox analysis, the prognosis was related to age, tumor size, regional node metastasis, and surgery. Molecular subtype remained no impact on BCSS. Radiotherapy (RT) was associated with better prognosis. Patients cannot benefit from chemotherapy. In Kaplan-Meier curve, triple-negative (P = 0.047) and HR-positive (P = 0.006) patients receiving RT had a superior BCSS than that not RT. HER2-positive patients cannot benefit from RT. However, adjusted Kaplan-Meier survival model showed that triple-negative (P = 0.019) but not HER2-positive (P = 0.575) or HR-positive (P = 0.574) patients receiving RT had a superior BCSS than that not RT.

CONCLUSIONS

Molecular subtype is not associated with the better prognosis of MBC. Patients could benefit from RT. However, triple-negative but not HR-positive or HER2-positive patients have superior survival after receiving RT.

An Update on the Molecular Pathology of Metaplastic Breast Cancer

Metaplastic breast cancer (MpBC) is a fascinating morphologic sub-type of breast cancer, characterised by intra-tumoural heterogeneity. By definition, these tumors show regions of metaplasia that can present as spindle, squamous, chondroid or even osseous differentiation. MpBC are typically triple-negative, and are therefore not targetable with hormone therapy or anti-HER2 therapies, leaving only chemotherapeutics for management. MpBC are known for their aggressive course and poor response to chemotherapy. We review herein the pathology and molecular landscape of MpBC and discuss opportunities for targetted therapies as well as immunotherapies.

Metaplastic breast cancer: an old histotype but a current therapeutic problem

Metaplastic breast cancer (MPBC) is a rare and aggressive tumor type in great need of satisfactory therapies. Although most cases of MPBC are 'triple negative', they are nonetheless related to worse outcomes compared with other triple-negative invasive tumors. MPBC presents high levels of genetic and molecular heterogeneity, suggesting that novel targeted therapies can be exploited. Overexpression of PD-L1 and high levels of tumor-infiltrating lymphocytes have also been observed in these tumors, suggesting a role for immunotherapy. We present an updated literature revision on clinical, histopathological and molecular features of MPBC and their significance to prognosis and therapy options. We discuss emerging efforts to improve and personalize prognostic and therapeutic approaches, exploiting the molecular signature of MPBC with targeted therapies and immunotherapies.

Recent Discoveries of Macromolecule- and Cell-Based Biomarkers and Therapeutic Implications in Breast Cancer

Breast cancer is the most commonly diagnosed cancer type and the leading cause of cancer-related mortality in women worldwide. Breast cancer is fairly heterogeneous and reveals six molecular subtypes: luminal A, luminal B, HER2+, basal-like subtype (ER−, PR−, and HER2−), normal breast-like, and claudin-low. Breast cancer screening and early diagnosis play critical roles in improving therapeutic outcomes and prognosis. Mammography is currently the main commercially available detection method for breast cancer; however, it has numerous limitations. Therefore, reliable noninvasive diagnostic and prognostic biomarkers are required. Biomarkers used in cancer range from macromolecules, such as DNA, RNA, and proteins, to whole cells. Biomarkers for cancer risk, diagnosis, proliferation, metastasis, drug resistance, and prognosis have been identified in breast cancer. In addition, there is currently a greater demand for personalized or precise treatments; moreover, the identification of novel biomarkers to further the development of new drugs is urgently needed. In this review, we summarize and focus on the recent discoveries of promising macromolecules and cell-based biomarkers for the diagnosis and prognosis of breast cancer and provide implications for therapeutic strategies.

The Role of Nitric Oxide in Cancer: Master Regulator or NOt?

Nitric oxide (NO) is a key player in both the development and suppression of tumourigenesis depending on the source and concentration of NO. In this review, we discuss the mechanisms by which NO induces DNA damage, influences the DNA damage repair response, and subsequently modulates cell cycle arrest. In some circumstances, NO induces cell cycle arrest and apoptosis protecting against tumourigenesis. NO in other scenarios can cause a delay in cell cycle progression, allowing for aberrant DNA repair that promotes the accumulation of mutations and tumour heterogeneity. Within the tumour microenvironment, low to moderate levels of NO derived from tumour and endothelial cells can activate angiogenesis and epithelial-to-mesenchymal transition, promoting an aggressive phenotype. In contrast, high levels of NO derived from inducible nitric oxide synthase (iNOS) expressing M1 and Th1 polarised macrophages and lymphocytes may exert an anti-tumour effect protecting against cancer. It is important to note that the existing evidence on immunomodulation is mainly based on murine iNOS studies which produce higher fluxes of NO than human iNOS. Finally, we discuss different strategies to target NO related pathways therapeutically. Collectively, we present a picture of NO as a master regulator of cancer development and progression.

A comprehensive overview of metaplastic breast cancer: clinical features and molecular aberrations

Metaplastic breast cancer (MpBC) is an exceedingly rare breast cancer variant that is therapeutically challenging and aggressive. MpBC is defined by the histological presence of at least two cellular types, typically epithelial and mesenchymal components. This variant harbors a triple-negative breast cancer (TNBC) phenotype, yet has a worse prognosis and decreased survival compared to TNBC. There are currently no standardized treatment guidelines specifically for MpBC. However, prior studies have found that MpBC typically has molecular alterations in epithelial-to-mesenchymal transition, amplification of epidermal growth factor receptor, PI3K/Akt signaling, nitric oxide signaling, Wnt/β-catenin signaling, altered immune response, and cell cycle dysregulation. Some of these molecular alterations have been studied as therapeutic targets, in both the preclinical and clinical setting. This current review discusses the histological organization and cellular origins of MpBC, molecular alterations, the role of radiation therapy, and current clinical trials for MpBC.

Evaluating the therapeutic potential of ADAR1 inhibition for triple-negative breast cancer

Triple-negative breast cancer (TNBC) is the deadliest form of breast cancer. Unlike other types of breast cancer that can be effectively treated by targeted therapies, no such targeted therapy exists for all TNBC patients. The ADAR1 enzyme carries out A-to-I editing of RNA to prevent sensing of endogenous double-stranded RNAs. ADAR1 is highly expressed in breast cancer including TNBC. Here, we demonstrate that expression of ADAR1, specifically its p150 isoform, is required for the survival of TNBC cell lines. In TNBC cells, knockdown of ADAR1 attenuates proliferation and tumorigenesis. Moreover, ADAR1-knockdown leads to robust translational repression. ADAR1-dependent TNBC cell lines also exhibit elevated IFN stimulated gene expression. IFNAR1 reduction significantly rescued the proliferative defects of ADAR1 loss. These findings establish ADAR1 as a novel therapeutic target for TNBC tumors.

Evaluation of deacetylase inhibition in metaplastic breast carcinoma using multiple derivations of preclinical models of a new patient-derived tumor

Metaplastic breast carcinoma (MBC) is a clinically aggressive and rare subtype of breast cancer, with similar features to basal-like breast cancers. Due to rapid growth rates and characteristic heterogeneity, MBC is often unresponsive to standard chemotherapies; and novel targeted therapeutic discovery is urgently needed. Histone deacetylase inhibitors (DACi) suppress tumor growth and metastasis through regulation of the epithelial-to-mesenchymal transition axis in various cancers, including basal-like breast cancers. We utilized a new MBC patient-derived xenograft (PDX) to examine the effect of DACi therapy on MBC. Cell morphology, cell cycle-associated gene expressions, transwell migration, and metastasis were evaluated in patient-derived cells and tumors after treatment with romidepsin and panobinostat. Derivations of our PDX model, including cells, spheres, organoids, explants, and in vivo implanted tumors were treated. Finally, we tested the effects of combining DACi with approved chemotherapeutics on relative cell biomass. DACi significantly suppressed the total number of lung metastasis in vivo using our PDX model, suggesting a role for DACi in preventing circulating tumor cells from seeding distal tissue sites. These data were supported by our findings that DACi reduced cell migration, populations, and expression of mesenchymal-associated genes. While DACi treatment did affect cell cycle-regulating genes in vitro, tumor growth was not affected compared to controls. Importantly, gene expression results varied depending on the cellular or tumor system used, emphasizing the importance of using multiple derivations of cancer models in preclinical therapeutic discovery research. Furthermore, DACi sensitized and produced a synergistic effect with approved oncology therapeutics on inherently resistant MBC. This study introduced a role for DACi in suppressing the migratory and mesenchymal phenotype of MBC cells through regulation of the epithelial-mesenchymal transition axis and suppression of the CTC population. Preliminary evidence that DACi treatment in combination with MEK1/2 inhibitors exerts a synergistic effect on MBC cells was also demonstrated.

Antiglioma Activity of Aryl and Amido-Aryl Acetamidine Derivatives Targeting iNOS: Synthesis and Biological Evaluation

Nitric oxide is an important inflammation mediator with a recognized role in the development of different cancers. Gliomas are primary tumors of the central nervous system with poor prognosis, and the expression of the inducible nitric oxide synthase correlates with the degree of malignancy, changes in vascular reactivity, and neo-angiogenesis. Therefore, targeting the nitric oxide biosynthesis appears as a potential strategy to impair glioma progression. In the present work a set of aryl and amido-aryl acetamidine derivatives were synthesized to obtain new potent and selective inducible nitric oxide synthase inhibitors with improved physicochemical parameters with respect to the previously published molecules. Compound 17 emerged as the most promising inhibitor and was evaluated on C6 rat glioma cell line, showing antiproliferative effects and high selectivity over astrocytes.

Breast Cancer: A Molecularly Heterogenous Disease Needing Subtype-Specific Treatments

Breast cancer is the most commonly occurring cancer in women. There were over two-million new cases in world in 2018. It is the second leading cause of death from cancer in western countries. At the molecular level, breast cancer is a heterogeneous disease, which is characterized by high genomic instability evidenced by somatic gene mutations, copy number alterations, and chromosome structural rearrangements. The genomic instability is caused by defects in DNA damage repair, transcription, DNA replication, telomere maintenance and mitotic chromosome segregation. According to molecular features, breast cancers are subdivided in subtypes, according to activation of hormone receptors (estrogen receptor and progesterone receptor), of human epidermal growth factors receptor 2 (HER2), and or BRCA mutations. In-depth analyses of the molecular features of primary and metastatic breast cancer have shown the great heterogeneity of genetic alterations and their clonal evolution during disease development. These studies have contributed to identify a repertoire of numerous disease-causing genes that are altered through different mutational processes. While early-stage breast cancer is a curable disease in about 70% of patients, advanced breast cancer is largely incurable. However, molecular studies have contributed to develop new therapeutic approaches targeting HER2, CDK4/6, PI3K, or involving poly(ADP-ribose) polymerase inhibitors for BRCA mutation carriers and immunotherapy.

CDK2-mediated site-specific phosphorylation of EZH2 drives and maintains triple-negative breast cancer

Triple-negative breast cancer (TNBC), which lacks estrogen receptor α (ERα), progesterone receptor, and human epidermal growth factor receptor 2 (HER2) expression, is closely related to basal-like breast cancer. Previously, we and others report that cyclin E/cyclin-dependent kinase 2 (CDK2) phosphorylates enhancer of zeste homolog 2 (EZH2) at T416 (pT416-EZH2). Here, we show that transgenic expression of phospho-mimicking EZH2 mutant EZH2^T416D in mammary glands leads to tumors with TNBC phenotype. Coexpression of EZH2^T416D in mammary epithelia of HER2/Neu transgenic mice reprograms HER2-driven luminal tumors into basal-like tumors. Pharmacological inhibition of CDK2 or EZH2 allows re-expression of ERα and converts TNBC to luminal ERα-positive, rendering TNBC cells targetable by tamoxifen. Furthermore, the combination of either CDK2 or EZH2 inhibitor with tamoxifen effectively suppresses tumor growth and markedly improves the survival of the mice bearing TNBC tumors, suggesting that the mechanism-based combination therapy may be an alternative approach to treat TNBC.

EZH2 phosphorylation by CDK2 promotes progression of triple-negative breast cancer (TNBC). Here, the authors show that this signaling axis downregulates ERα, and thus combinatorial blockade of CDK2 and EZH2 sensitizes TNBC cells to tamoxifen.

Germline variability and tumor expression level of ribosomal protein gene RPL28 are associated with survival of metastatic colorectal cancer patients

This study investigated the potential of single nucleotide polymorphisms as predictors of survival in two cohorts comprising 417 metastatic colorectal cancer (mCRC) patients treated with the FOLFIRI (folinic acid, 5-fluorouracil and irinotecan) regimen. The rs4806668G > T of the ribosomal protein gene RPL28 was associated with shorter progression-free survival and overall survival by 5 and 9 months (P = 0.002), with hazard ratios of 3.36 (P < 0.001) and 3.07 (P = 0.002), respectively. The rs4806668T allele was associated with an increased RPL28 expression in transverse normal colon tissues (n = 246, P = 0.007). RPL28 expression was higher in colorectal tumors compared to paired normal tissues by up to 124% (P < 0.001) in three independent datasets. Metastatic cases with highest RPL28 tumor expression had a reduced survival in two datasets (n = 88, P = 0.009 and n = 56, P = 0.009). High RPL28 was further associated with changes in immunoglobulin and extracellular matrix pathways. Repression of RPL28 reduced proliferation by 1.4-fold to 5.6-fold (P < 0.05) in colon cancer HCT116 and HT-29 cells. Our findings suggest that the ribosomal RPL28 protein may influence mCRC outcome.

Therapeutic landscape of metaplastic breast cancer

Metaplastic breast carcinomas (MPBC) are rare, aggressive and relatively chemorefractory tumors with a high unmet need. While most are "triple negative" and lack expression of estrogen, progesterone and HER2 receptors, MPBC are associated with worse outcomes compared to conventional triple negative invasive tumors. MPBCs are genetically heterogeneous and harbor somatic mutations, most frequently in TP53, PIK3CA and PTEN, with emerging studies suggesting a role for novel targeted therapies. These tumors have also been associated with overexpression of PD-L1 and tumor-infiltrating lymphocytes suggesting an endogenous immune response and therefore a rationale for treatment with immunotherapies. Here, we focus on therapeutic options for this difficult to treat breast cancer subtype and encourage physicians to consider targeted therapies/immunotherapies as part of ongoing clinical trials.

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.

Metaplastic breast carcinoma: Current therapeutic approaches and novel targeted therapies

Metaplastic breast carcinoma (MBC) is a rare subtype of invasive breast cancer consisting of various combinations of malignant epithelial and mesenchymal cells. Its aggressive growth pattern combined with its histological heterogeneity account for MBC's characteristic resistance to systemic therapies, which subsequently leads to increased risk of recurrence and breast cancer mortality compared with other invasive mammary carcinomas. The aim of this review is to discuss the current therapeutic approaches, both in loco-regional as well as in systemic management of MBC. With the accumulation of knowledge from histopathologic assessment and the increasing identification of underlying molecular aberrations, emerging, novel targeted therapies will enable physicians to implement a more individualized and efficacious therapeutic strategy, leading hopefully to an improvement in the poor prognosis of MBC.

Cancer therapeutic targeting using mutant-p53-specific siRNAs

Mutations in Tp53 compromise therapeutic response, due either to the dominant-negative effect over the functional wild-type allele; or as a result of the survival advantage conferred by mutant p53 to which cancer cells become addicted. Thus, targeting mutant p53 represents an effective therapeutic strategy to treat over half of all cancers. We have therefore generated a series of small-interfering-RNAs, capable of targeting four p53 hot-spot mutants which represent ~20% of all p53 mutations. These mutant–p53-specific siRNAs (MupSi) are highly specific in silencing the expression of the intended mutants without affecting wild-type p53. Functionally, these MupSis induce cell death by abrogating both the addiction to mutant p53 and the dominant-negative effect; and retard tumor growth in xenografts when administered in a therapeutic setting. These data together demonstrate the possibility of targeting mutant p53 specifically to improve clinical outcome.

Phenotypic and molecular dissection of metaplastic breast cancer and the prognostic implications

Metaplastic breast carcinoma (MBC) is relatively rare but accounts for a significant proportion of global breast cancer mortality. This group is extremely heterogeneous and by definition exhibits metaplastic change to squamous and/or mesenchymal elements, including spindle, squamous, chondroid, osseous, and rhabdomyoid features. Clinically, patients are more likely to present with large primary tumours (higher stage), distant metastases, and overall, have shorter 5-year survival compared to invasive carcinomas of no special type. The current World Health Organisation (WHO) diagnostic classification for this cancer type is based purely on morphology - the biological basis and clinical relevance of its seven sub-categories are currently unclear. By establishing the Asia-Pacific MBC (AP-MBC) Consortium, we amassed a large series of MBCs (n = 347) and analysed the mutation profile of a subset, expression of 14 breast cancer biomarkers, and clinicopathological correlates, contextualising our findings within the WHO guidelines. The most significant indicators of poor prognosis were large tumour size (T3; p = 0.004), loss of cytokeratin expression (lack of staining with pan-cytokeratin AE1/3 antibody; p = 0.007), EGFR overexpression (p = 0.01), and for 'mixed' MBC, the presence of more than three distinct morphological entities (p = 0.007). Conversely, fewer morphological components and EGFR negativity were favourable indicators. Exome sequencing of 30 cases confirmed enrichment of TP53 and PTEN mutations, and intriguingly, concurrent mutations of TP53, PTEN, and PIK3CA. Mutations in neurofibromatosis-1 (NF1) were also overrepresented [16.7% MBCs compared to ∼5% of breast cancers overall; enrichment p = 0.028; mutation significance p = 0.006 (OncodriveFM)], consistent with published case reports implicating germline NF1 mutations in MBC risk. Taken together, we propose a practically minor but clinically significant modification to the guidelines: all WHO_1 mixed-type tumours should have the number of morphologies present recorded, as a mechanism for refining prognosis, and that EGFR and pan-cytokeratin expression are important prognostic markers. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

The Role of RNA Editing in Cancer Development and Metabolic Disorders

Numerous human diseases arise from alterations of genetic information, most notably DNA mutations. Thought to be merely the intermediate between DNA and protein, changes in RNA sequence were an afterthought until the discovery of RNA editing 30 years ago. RNA editing alters RNA sequence without altering the sequence or integrity of genomic DNA. The most common RNA editing events are A-to-I changes mediated by adenosine deaminase acting on RNA (ADAR), and C-to-U editing mediated by apolipoprotein B mRNA editing enzyme, catalytic polypeptide 1 (APOBEC1). Both A-to-I and C-to-U editing were first identified in the context of embryonic development and physiological homeostasis. The role of RNA editing in human disease has only recently started to be understood. In this review, the impact of RNA editing on the development of cancer and metabolic disorders will be examined. Distinctive functions of each RNA editase that regulate either A-to-I or C-to-U editing will be highlighted in addition to pointing out important regulatory mechanisms governing these processes. The potential of developing novel therapeutic approaches through intervention of RNA editing will be explored. As the role of RNA editing in human disease is elucidated, the clinical utility of RNA editing targeted therapies will be needed. This review aims to serve as a bridge of information between past findings and future directions of RNA editing in the context of cancer and metabolic disease.

Prognosis in different subtypes of metaplastic breast cancer: a population-based analysis

BACKGROUND

Metaplastic breast cancer (MpBC) is a rare histological subtype of breast cancer recognized as a unique pathologic entity in 2000. However, the pathogenesis, optimal therapy, and prognosis of MpBC and the potential effect of systemic treatments on different subtypes of MpBC are not well defined.

METHODS

A retrospective population-based study was performed to identify breast cancer patients with MpBC and other triple-negative breast cancers (TNBC) between 2010 and 2014 using the surveillance, Epidemiology, and End Results (SEER) database. Chi-square test was used to analyze characteristics between subgroups. Kaplan-Meier analysis and Multivariate Cox regressions were used to evaluate overall survival (OS) of MpBC, TNBC, and MpBC subgroups. Competing risk analysis and multivariate regression model of competing risk were used to assess breast cancer-specific survival (BCSS) of MpBC and TNBC RESULTS: We identified a study cohort of 22,433 patients (1112 MpBC and 21,321 TNBC). MpBC correlated with older population, larger tumor size and less lymph node involvement, and TNBC phenotype. Patients with MpBC especially with triple-negative subtype (TN-MpBC) had worse survival than the overall TNBC population. However, the prognosis of MpBC without triple-negative subtype (non-TN MpBC) was not different from that of TNBC. In Kaplan-Meier analysis, chemotherapy was not associated with significant difference in OS of TN-MpBC. In non-TN MpBC group, the 3-year OS was 79.8% for patients receiving chemotherapy and 70.5% in patients without chemotherapy, and chemotherapy was associated (P = 0.033) with improved OS. Within the MpBC patients, radiotherapy was significantly (HR 1.544; 95% CI 1.148-2.078; P = 0.004) associated with improved OS and (HR 1.474; 95% CI 1.067-2.040; P = 0.019) BCSS.

CONCLUSIONS

Patients with TN-MpBC had worse prognosis than TNBC and chemotherapy was not associated with improved survival. In contrast, non-TN MpBC may derive survival benefit from chemotherapy and radiotherapy.

Pharmacological Inhibition of NOS Activates ASK1/JNK Pathway Augmenting Docetaxel-Mediated Apoptosis in Triple-Negative Breast Cancer

Purpose: Chemoresistance in triple-negative breast cancer (TNBC) is associated with the activation of a survival mechanism orchestrated by the endoplasmic reticulum (EnR) stress response and by inducible nitric oxide synthase (iNOS). Our aim was to determine the effects of pharmacologic NOS inhibition on TNBC.Experimental Design: TNBC cell lines, SUM-159PT, MDA-MB-436, and MDA-MB-468, were treated with docetaxel and NOS inhibitor (L-NMMA) for 24, 48, and 72 hours. Apoptosis was assessed by flow cytometry using Annexin-V and propidium iodide. Western blot was used to assess ER stress and apoptosis, and rtPCR was used to evaluate s-XBP1. TNBC patient-derived xenografts (PDX) were treated either with vehicle, docetaxel, or combination therapy (NOS inhibition + docetaxel). Mouse weight and tumor volumes were recorded twice weekly. Docetaxel concentration was determined using mass spectrometry. To quantify proliferation and apoptosis, PDX tumor samples were stained using Ki67 and TUNEL assay.Results:In vitro, L-NMMA ameliorated the iNOS upregulation associated with docetaxel. Apoptosis increased when TNBC cells were treated with combination therapy. In TNBC PDXs, combination therapy significantly reduced tumor volume growth and increased survival proportions. In the BCM-5998 PDX model, intratumoral docetaxel concentration was higher in mice receiving combination therapy. Coupling docetaxel with NOS inhibition increased EnR-stress response via coactivation of ATF4 and CHOP, which triggered the pASK1/JNK proapoptotic pathway, promoting cleavage of caspases 3 and 9.Conclusions: iNOS is a critical target for docetaxel resistance in TNBC. Pharmacologic inhibition of NOS enhanced chemotherapy response in TNBC PDX models. Combination therapy may improve prognosis and prevent relapse in TNBC patients who have failed conventional chemotherapy. Clin Cancer Res; 24(5); 1152-62. ©2018 AACR.

Evaluation of Prognosis in Hormone Receptor-Positive/HER2-Negative and Lymph Node-Negative Breast Cancer With Low Oncotype DX Recurrence Score

INTRODUCTION

Hormone receptor-positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancers without lymph node metastasis have good prognosis. We compared the prognosis of hormone receptor-positive, HER2-negative, lymph node-negative cancers with Oncotype DX score ranges of 1 to 10 (1-10 group) and 11 to < 18 (11-18 group).

PATIENTS AND METHODS

A total of 107 cases in the 1-10 group and 225 cases in the 11-18 group were reviewed. All patients received surgery. The use of chemotherapy, radiotherapy, and endocrine therapy, and overall survival (OS), disease-free survival (DFS), and distant metastasis were compared between groups.

RESULTS

There were no statistical differences in the use of chemotherapy (5.05% vs. 6.05%, P = .724) or radiotherapy (52.53% vs. 59.07%, P = .276) between the 1-10 group and the 11-18 group, respectively. The median OS and DFS were 47 and 45 months, respectively, in the 1-10 group, and 49 and 48 months in the 11-18 group. No significant difference was seen in OS (P = .995), DFS (P = .148), or rates of metastasis (P = .998). The 11-18 group had more death events and distant metastasis (death, 5 events; recurrence, 2 events; metastasis, 2 events) than the 1-10 group (death, 0 events; recurrence, 4 events; metastasis, 0 events). The majority of recurrences seen in both groups were in young patients who failed to comply with their endocrine therapy regimen.

CONCLUSION

Patients in both the 1-10 group and the 11-18 group had good prognoses. Those who experienced recurrence were more likely to be premenopausal and to have failed to comply with the recommended endocrine therapy regimen. Endocrine therapy remains important in these patients.

Proteomic characterization of EL4 lymphoma-derived tumors upon chemotherapy treatment reveals potential roles for lysosomes and caspase-6 during tumor cell death in vivo

The murine mouse lymphoblastic lymphoma cell line (EL4) tumor model is an established in vivo apoptosis model for the investigation of novel cancer imaging agents and immunological treatments due to the rapid and significant response of the EL4 tumors to cyclophosphamide and etoposide combination chemotherapy. Despite the utility of this model system in cancer research, little is known regarding the molecular details of in vivo tumor cell death. Here, we report the first in-depth quantitative proteomic analysis of the changes that occur in these tumors upon cyclophosphamide and etoposide treatment in vivo. Using a label-free quantitative proteomic approach a total of 5838 proteins were identified in the treated and untreated tumors, of which 875 were determined to change in abundance with statistical significance. Initial analysis of the data reveals changes that may have been predicted, such as the downregulation of ribosomes, but demonstrates the robustness of the dataset. Analysis of the dataset also reveals the unexpected downregulation of caspase-3 and an upregulation of caspase-6 in addition to a global upregulation of lysosomal proteins in the bulk of the tumor.

African American patients with breast cancer have worse prognosis than white patients in certain subtypes and stages

PURPOSE

Racial disparity of breast cancer in each subtype and substage is not clear.

METHODS

We reviewed 156,938 patients with breast cancer from 2010 to 2012 from the National Cancer Institute Surveillance, Epidemiology, and End Results database. Breast cancer was subtyped by hormone receptor (HR) and human epidermal growth factor 2 (HER2) status as HR+/HER2-, HR+/HER2+, HR-/HER2+, and HR-/HER2-.

RESULTS

African American (AA) patients had worse overall survival (OS) and breast cancer cause-specific survival (BCSS) in HR+/HER2- stages III and IV breast cancer and HR-/HER2+ stage IV cancer; they had worse OS but not BCSS in HR+ /HER2- stage II cancer and HR-/HER2- stage II cancer.

CONCLUSION

AA patients with breast cancer had worse survival in certain subtype and stage, especially in ER+ breast cancer.

Whole-Exome Sequencing of Metaplastic Breast Carcinoma Indicates Monoclonality with Associated Ductal Carcinoma Component

Purpose: Although most human cancers display a single histology, there are unusual cases where two or more distinct tissue types present within a primary tumor. One such example is metaplastic breast carcinoma, a rare but aggressive cancer with a heterogeneous histology, including squamous, chondroid, and spindle cells. Metaplastic carcinomas often contain an admixed conventional ductal invasive or in situ mammary carcinoma component, and are typically triple-negative for estrogen receptor, progesterone receptor, and HER-2 amplification/overexpression. An unanswered question is the origin of metaplastic breast cancers. While they may arise independently from their ductal components, their close juxtaposition favors a model that postulates a shared origin, either as two derivatives from the same primary cancer or one histology as an outgrowth of the other. Understanding the mechanism of development of these tumors may inform clinical decisions.Experimental Design: We performed exome sequencing for paired metaplastic and adjacent conventional invasive ductal carcinomas in 8 patients and created a pipeline to identify somatic variants and predict their functional impact, without having normal tissue. We then determined the genetic relationships between the histologically distinct compartments.Results: In each case, the tumor components have nearly identical landscapes of somatic mutation, implying that the differing histologies do not derive from genetic clonal divergence.Conclusions: A shared origin for tumors with differing histologies suggests that epigenetic or noncoding changes may mediate the metaplastic phenotype and that alternative therapeutic approaches, including epigenetic therapies, may be required for metaplastic breast cancers. Clin Cancer Res; 23(16); 4875-84. ©2017 AACR.

The Role of Tumor Microenvironment in Chemoresistance: To Survive, Keep Your Enemies Closer

Chemoresistance is a leading cause of morbidity and mortality in cancer and it continues to be a challenge in cancer treatment. Chemoresistance is influenced by genetic and epigenetic alterations which affect drug uptake, metabolism and export of drugs at the cellular levels. While most research has focused on tumor cell autonomous mechanisms of chemoresistance, the tumor microenvironment has emerged as a key player in the development of chemoresistance and in malignant progression, thereby influencing the development of novel therapies in clinical oncology. It is not surprising that the study of the tumor microenvironment is now considered to be as important as the study of tumor cells. Recent advances in technological and analytical methods, especially ‘omics’ technologies, has made it possible to identify specific targets in tumor cells and within the tumor microenvironment to eradicate cancer. Tumors need constant support from previously ‘unsupportive’ microenvironments. Novel therapeutic strategies that inhibit such microenvironmental support to tumor cells would reduce chemoresistance and tumor relapse. Such strategies can target stromal cells, proteins released by stromal cells and non-cellular components such as the extracellular matrix (ECM) within the tumor microenvironment. Novel in vitro tumor biology models that recapitulate the in vivo tumor microenvironment such as multicellular tumor spheroids, biomimetic scaffolds and tumor organoids are being developed and are increasing our understanding of cancer cell-microenvironment interactions. This review offers an analysis of recent developments on the role of the tumor microenvironment in the development of chemoresistance and the strategies to overcome microenvironment-mediated chemoresistance. We propose a systematic analysis of the relationship between tumor cells and their respective tumor microenvironments and our data show that, to survive, cancer cells interact closely with tumor microenvironment components such as mesenchymal stem cells and the extracellular matrix.

Review of Triple Negative Breast Cancer and the Impact of Inducible Nitric Oxide Synthase on Tumor Biology and Patient Outcomes

Triple negative breast cancers (TNBCs), which are defined as estrogen-receptor, progesterone-receptor, and HER2-receptor negative, account for 10-20% of breast cancers, and they are associated with early metastasis, chemotherapeutic resistance, and poor survival rates. One aspect of TNBC that complicates its prognosis and the development of new molecular therapeutic targets is its clinical and molecular heterogeneity. Herein we compare TNBC and basal cytokeratin-positive breast cancers. We examine the different TNBC molecular subtypes, based on gene expression profiling, which include basal-like, mesenchymal, and luminal androgen receptors, in the context of their biology and impact on TNBC prognosis. We explore the potential role of inducible nitric oxide synthase (iNOS) in TNBC tumor biology and treatment responses. iNOS has been shown to induce p53 mutation accumulation, basal-like gene signature enrichment, and transactivation of the epidermal growth factor receptor (EGFR) via S-nitrosylation, all of which are key components of TNBC biology. Moreover, iNOS predicts poor outcome in TNBC, and iNOS inhibitors show efficacy against TNBC when used in combination with chemotherapy. We discuss molecular targeted approaches, including EGFR, PARP, and VEGF inhibitors and immunotherapeutics, that are under consideration for the treatment of TNBC and what role, if any, iNOS may play in their success.