Although long non-coding RNAs (lncRNAs) predominately reside in the nucleus and exert their functions in many biological processes, their potential involvement in cytoplasmic signal transduction remains unexplored. Here, we identify a cytoplasmic lncRNA, LINK-A (long intergenic non-coding RNA for kinase activation), which mediates HB-EGF-triggered, EGFR:GPNMB heterodimer-dependent HIF1α phosphorylation at Tyr 565 and Ser 797 by BRK and LRRK2, respectively. These events cause HIF1α stabilization, HIF1α-p300 interaction, and activation of HIF1α transcriptional programs under normoxic conditions. Mechanistically, LINK-A facilitates the recruitment of BRK to the EGFR:GPNMB complex and BRK kinase activation. The BRK-dependent HIF1α Tyr 565 phosphorylation interferes with Pro 564 hydroxylation, leading to normoxic HIF1α stabilization. Both LINK-A expression and LINK-A-dependent signalling pathway activation correlate with triple-negative breast cancer (TNBC), promoting breast cancer glycolysis reprogramming and tumorigenesis. Our findings illustrate the magnitude and diversity of cytoplasmic lncRNAs in signal transduction and highlight the important roles of lncRNAs in cancer.

Extracellular interaction between programmed death ligand-1 (PD-L1) and programmed cell death protein-1 (PD-1) leads to tumour-associated immune escape. Here we show that the immunosuppression activity of PD-L1 is stringently modulated by ubiquitination and N-glycosylation. We show that glycogen synthase kinase 3β (GSK3β) interacts with PD-L1 and induces phosphorylation-dependent proteasome degradation of PD-L1 by β-TrCP. In-depth analysis of PD-L1 N192, N200 and N219 glycosylation suggests that glycosylation antagonizes GSK3β binding. In this regard, only non-glycosylated PD-L1 forms a complex with GSK3β and β-TrCP. We also demonstrate that epidermal growth factor (EGF) stabilizes PD-L1 via GSK3β inactivation in basal-like breast cancer. Inhibition of EGF signalling by gefitinib destabilizes PD-L1, enhances antitumour T-cell immunity and therapeutic efficacy of PD-1 blockade in syngeneic mouse models. Together, our results link ubiquitination and glycosylation pathways to the stringent regulation of PD-L1, which could lead to potential therapeutic strategies to enhance cancer immune therapy efficacy.

The purpose of this study was to determine the association between body mass index (BMI) measurements (baseline BMI and changes in BMI during neoadjuvant systemic treatment [NST]) and clinical efficacy (pathologic complete response [pCR] rate and survival outcomes) in locally advanced breast cancer (LABC). We hypothesized that high baseline BMI and increases in BMI during NST are associated with lower pCR rates and poorer clinical outcomes in LABC. We retrospectively reviewed the medical records of 1002 patients, 204 with primary inflammatory breast cancer (IBC) and 798 with stage III non-IBC, who underwent standard NST and definitive surgery between November 1, 2006, and December 31, 2012. The median follow-up time for the survivors was 19.6 months (0.4 - 67.8 months). The pCR rates of patients whose BMI increased or decreased were 23.2% and 18.1%, respectively, (p=0.048). The unadjusted overall survival (OS) was significantly better in the group with increased BMI (p=0.006). However, increased BMI was not an independent predictor of pCR and clinical outcomes (recurrence-free survival and OS) after adjusting for other clinical variables. In subset analyses, increased BMI as a continuous variable was an independent predictor of higher pCR rates in the normal BMI/underweight group (odds ratio [OR]=1.35, 95% confidence interval [CI]: 1.06-0.71, p=0.015). Increased BMI (BMI change ≥0 vs. <0) was also an independent predictor of pCR (OR=1.65, 95% CI: 1.00-2.72, p=0.049) in the postmenopausal group. Our results show that increasing BMI shows improved clinical outcome in terms of better pCR rates in normal BMI/underweight group and in the postmenopausal group. These results contradict previously reported findings on the association between high BMI and poor clinical efficacy regarding pCR rate and survival outcomes in early-stage breast cancer. Thus, the role of BMI in breast cancer may depend on patients' clinical characteristics such as advanced stage.

Because of its high rate of metastasis, inflammatory breast cancer (IBC) has a poor prognosis compared with non-inflammatory types of breast cancer (non-IBC). In a recent study, Lehmann and colleagues identified seven subtypes of triple-negative breast cancer (TNBC). We hypothesized that the distribution of TNBC subtypes differs between TN-IBC and TN-non-IBC. We determined the subtypes and compared clinical outcomes by subtype in TN-IBC and TN-non-IBC patients.

Taxanes are among the drugs most commonly used for preoperative chemotherapy for breast cancer. Taxanes induce mitotic arrest and subsequent apoptosis. The spindle-assembly checkpoint (SAC) is known to be activated during mitosis, along with cyclin-dependent kinase-1 (CDK1), and is required for taxane-induced cell death. We hypothesized that CDK1 activity predicts response to taxane-containing chemotherapy. This study included breast cancer patients who received preoperative chemotherapy- taxane-containing treatment followed by anthracycline-based treatment-and then underwent surgery. Before starting taxane-containing chemotherapy, patients underwent fine-needle aspiration biopsy, and the biopsy samples were incubated in paclitaxel solution to measure CDK activity. Clinical were evaluated after taxane therapy, and pathological resposes were evaluated after completion of all preoperative chemotherapy. Thirty five patients were eligible for analysis of clinical response to taxane-containing therapy. Twenty-six patients had taxane-sensitive and 9 taxane-resistant tumors. Using a cut-off of CDK activity determined by the ROC analysis, patients were classified into SAC function and dysfunction groups. Univariate logistic regression analysis with clinicopathologic parameters showed that only CDK-based SAC functionality was significantly correlated with clinical response (P =0.017). No significant correlation was observed between SAC functionality and pathologic response. CDK-based SAC functionality significantly predicted clinical response (P =.0072, overall agreement = 71.4%), and this is a unique mechanism-based marker for predicting taxane chemosensitivity. Further, large prospective study is needed to determine CDK-based SAC functionality could be developed as a predictive biomarker.

Epithelial-mesenchymal transition (EMT) is associated with characteristics of breast cancer stem cells, including chemoresistance and radioresistance. However, it is unclear whether EMT itself or specific EMT regulators play causal roles in these properties. Here we identify an EMT-inducing transcription factor, zinc finger E-box binding homeobox 1 (ZEB1), as a regulator of radiosensitivity and DNA damage response. Radioresistant subpopulations of breast cancer cells derived from ionizing radiation exhibit hyperactivation of the kinase ATM and upregulation of ZEB1, and the latter promotes tumour cell radioresistance in vitro and in vivo. Mechanistically, ATM phosphorylates and stabilizes ZEB1 in response to DNA damage, ZEB1 in turn directly interacts with USP7 and enhances its ability to deubiquitylate and stabilize CHK1, thereby promoting homologous recombination-dependent DNA repair and resistance to radiation. These findings identify ZEB1 as an ATM substrate linking ATM to CHK1 and the mechanism underlying the association between EMT and radioresistance.

A phase III clinical trial showed gemcitabine chemotherapy combined with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor erlotinib significantly improved overall survival in patients with advanced pancreatic cancer. Therefore, we studied whether addition of gemcitabine to erlotinib in cancer cells having intrinsic or acquired erlotinib resistance could restore chemosensitization in these cells. We studied the synergistic effect of erlotinib and gemcitabine in EGFR-overexpressing A-431 cells with acquired erlotinib resistance and in intrinsic erlotinib-resistant triple negative breast cancer (TNBC) BT-549, MDA-MB-231 and MDA-MB-468 cell lines. Erlotinib and gemcitabine were synergistic in both parental intrinsically erlotinib-sensitive A-431 cells (combination index = 0.69 at the effective dose [ED(50)]) and in two A-431 cell pools that had acquired erlotinib resistance (combination indices = 0.63 and 0.49 at ED(50)). The synergistic effect of erlotinib and gemcitabine on cancer cells did not require sensitivity to erlotinib provided that erlotinib can inhibit EGFR. The restoration of sensitivity by gemcitabine occurred through downregulation of phosphorylated Akt (p-Akt), which suggests that PI3K-PTEN-Akt activity is important to the synergism between the two agents. In A-431 parental cells, treatment with gemcitabine followed by erlotinib - but not the reverse sequence - was superior to erlotinib alone. The importance of the order of administration maybe due to the downregulation of p-Akt by gemcitabine in a dose- and time-dependent manner in cells with intrinsic or acquired erlotinib resistance. Our data show that gemcitabine increased the cytotoxic effect of erlotinib by downregulating p-Akt in EGFR-overexpressing cells with either intrinsic or acquired erlotinib resistance.

ACE inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) may have anti-tumor properties. We investigated whether the use of ACEI/ARBs affects the clinical outcomes of primary breast cancer patients receiving taxane and anthracycline-based neoadjuvant chemotherapy.

Paclitaxel is used widely in the treatment of breast cancer. Not all tumors respond to this drug, however, and the characteristics that distinguish resistant tumors from sensitive tumors are not well defined. Activation of the spindle assembly checkpoint is required for paclitaxel-induced cell death. We hypothesized that cyclin-dependent kinase (CDK) 1 activity and CDK2 activity in cancer cells, which reflect the activation state of the spindle assembly checkpoint and the growth state, respectively, predict sensitivity to paclitaxel.

Protein glycosylation provides proteomic diversity in regulating protein localization, stability, and activity; it remains largely unknown whether the sugar moiety contributes to immunosuppression. In the study of immune receptor glycosylation, we showed that EGF induces programmed death ligand 1 (PD-L1) and receptor programmed cell death protein 1 (PD-1) interaction, requiring β-1,3-N-acetylglucosaminyl transferase (B3GNT3) expression in triple-negative breast cancer. Downregulation of B3GNT3 enhances cytotoxic T cell-mediated anti-tumor immunity. A monoclonal antibody targeting glycosylated PD-L1 (gPD-L1) blocks PD-L1/PD-1 interaction and promotes PD-L1 internalization and degradation. In addition to immune reactivation, drug-conjugated gPD-L1 antibody induces a potent cell-killing effect as well as a bystander-killing effect on adjacent cancer cells lacking PD-L1 expression without any detectable toxicity. Our work suggests targeting protein glycosylation as a potential strategy to enhance immune checkpoint therapy.

Sustained energy starvation leads to activation of AMP-activated protein kinase (AMPK), which coordinates energy status with numerous cellular processes including metabolism, protein synthesis, and autophagy. Here, we report that AMPK phosphorylates the histone methyltransferase EZH2 at T311 to disrupt the interaction between EZH2 and SUZ12, another core component of the polycomb repressive complex 2 (PRC2), leading to attenuated PRC2-dependent methylation of histone H3 at Lys27. As such, PRC2 target genes, many of which are known tumor suppressors, were upregulated upon T311-EZH2 phosphorylation, which suppressed tumor cell growth both in cell culture and mouse xenografts. Pathologically, immunohistochemical analyses uncovered a positive correlation between AMPK activity and pT311-EZH2, and higher pT311-EZH2 correlates with better survival in both ovarian and breast cancer patients. Our finding suggests that AMPK agonists might be promising sensitizers for EZH2-targeting cancer therapies.

Metastatic breast cancer (MBC) patients with bone only metastasis (BOM) are a unique population with limited characterization. We identified patients followed at MD Anderson Cancer Center from 01/01/1997 to 12/31/2015 for at least 6 months with a BOM diagnosis as first site of metastasis. Tumor subtype (TS) was assessed by initial breast biopsy immunohistochemistry using hormonal receptor (HR) and HER2 status, with four subtypes identified: HR+/HER2-, HR+/HER2+, HR-/HER2-, HR-/HER2+. HR+ was defined as estrogen receptor or progesterone receptor ≥1%. We identified 1445 patients with BOM, 1048 with TS data available. Among these patients, the majority were HR+/HER2- (78%). Median time from breast cancer diagnosis to first bone metastasis was 2.3 years (95% CI 2.1, 2.5) and varied significantly by TS, with longer time to distant disease in HR+/HER2- patients relative to all other TS (p < .0001). Median overall survival (OS) from breast cancer diagnosis was 8.7 years (95% CI 8.0, 9.7) and varied significantly by TS with poorer OS for HR-/HER2- and HR-/HER2+ patients relative to HR+/HER2- TS (p < .0001). The 442 patients with de novo BOM disease, defined as bone metastasis diagnosis within 4 months of breast cancer diagnosis, had significantly shorter OS (p < .0001). Overall, several higher risk BOM subsets were identified in this analysis, most notably HR-/HER2+ and HR-/HER2- TS and de novo BOM patients.

Radium-223 dichloride (Ra-223) is a targeted alpha therapy that induces localized cytotoxicity in bone metastases. We evaluated the efficacy and safety of Ra-223 plus hormonal therapy in hormone receptor-positive (HR+), bone-dominant metastatic breast cancer.

KRAS G12C inhibitor (G12Ci) has produced encouraging, albeit modest and transient, clinical benefit in pancreatic ductal adenocarcinoma (PDAC). Identifying and targeting resistance mechanisms to G12Ci treatment is therefore crucial. To better understand the tumor biology of the KRAS G12C allele and possible bypass mechanisms, we developed a novel autochthonous KRAS G12C -driven PDAC model. Compared to the classical KRAS G12D PDAC model, the G12C model exhibit slower tumor growth, yet similar histopathological and molecular features. Aligned with clinical experience, G12Ci treatment of KRAS G12C tumors produced modest impact despite stimulating a 'hot' tumor immune microenvironment. Immunoprofiling revealed that CD24, a 'do-not-eat-me' signal, is significantly upregulated on cancer cells upon G12Ci treatment. Blocking CD24 enhanced macrophage phagocytosis of cancer cells and significantly sensitized tumors to G12Ci treatment. Similar findings were observed in KRAS G12D -driven PDAC. Our study reveals common and distinct oncogenic KRAS allele-specific biology and identifies a clinically actionable adaptive mechanism that may improve the efficacy of oncogenic KRAS inhibitor therapy in PDAC.

PARP inhibitors are considered promising anticancer agents and currently being tested in clinical trials in hereditary breast cancer patients harboring mutations in BRCA1 and BRCA2 genes. In this study, we investigated the antiproliferative effects and mechanism of PARP inhibitors ABT-888 (Veliparib), BSI-201 (Iniparib) and AZD228 (Olaparib) in breast cancer cell lines with BRCA1 or BRCA2 mutations and 9 different BRCA wild-type cell lines with BRCA1 allelic loss. We found that AZD2281 was the most potent in the PARP inhibitors and induces significant growth inhibition (~95%) in BRCA1 mutant (HCC‑1937, MDA-MB-436, and SUM-149PT) and BRCA2 mutant (HCC‑1428) cell lines. AZD2281 treatment also resulted in growth inhibition ranging from 20 to 50% in cells with BRCA1 allelic loss, including ER(+), HER2/Neu(+) and triple-negative breast cancer (TNBC) cells, but showed no effect in cells without with type BRCA without allelic loss. Knocking down of BRCA1 or BRCA2 in TNBC cells with BRCA1 allelic loss by RNA interference significantly enhanced AZD2281-induced growth inhibition and induced significant autophagy that was associated with mitophagy in cells with BRCA mutations. Inhibition of autophagy by gene knockdown significantly diminished AZD2281-induced mitophagy and apoptosis, indicating that autophagic process mediates some of the downstream effects of PARP inhibitors. In conclusion, our data provide the first evidence of PARP inhibitor AZD2281 autophagy and mitophagy in breast cancer cell lines with BRCA mutations or BRCA-allelic loss. In addition, our results indicate that the patients with BRCA1 allelic loss may also benefit from PARP inhibitor therapy if BRCA is further inhibited.

The incidence of breast cancer diagnosed during pregnancy is expected to increase as more women delay childbearing in the United States. Treatment of cancer in pregnant women requires prudent judgment to balance the benefit to the cancer patient and the risks to the fetus. Prospective data on the outcomes of children exposed to chemotherapy in utero are limited for the breast cancer population.

To determine whether functional proteomics improves breast cancer classification and prognostication and can predict pathological complete response (pCR) in patients receiving neoadjuvant taxane and anthracycline-taxane-based systemic therapy (NST).

A number of studies of copy number imbalances (CNIs) in breast tumors support associations between individual CNIs and patient outcomes. However, no pattern or signature of CNIs has emerged for clinical use. We determined copy number (CN) gains and losses using high-density molecular inversion probe (MIP) arrays for 971 stage I/II breast tumors and applied a boosting strategy to fit hazards models for CN and recurrence, treating chromosomal segments in a dose-specific fashion (-1 [loss], 0 [no change] and +1 [gain]). The concordance index (C-Index) was used to compare prognostic accuracy between a training (n = 728) and test (n = 243) set and across models. Twelve novel prognostic CNIs were identified: losses at 1p12, 12q13.13, 13q12.3, 22q11, and Xp21, and gains at 2p11.1, 3q13.12, 10p11.21, 10q23.1, 11p15, 14q13.2-q13.3, and 17q21.33. In addition, seven CNIs previously implicated as prognostic markers were selected: losses at 8p22 and 16p11.2 and gains at 10p13, 11q13.5, 12p13, 20q13, and Xq28. For all breast cancers combined, the final full model including 19 CNIs, clinical covariates, and tumor marker-approximated subtypes (estrogen receptor [ER], progesterone receptor, ERBB2 amplification, and Ki67) significantly outperformed a model containing only clinical covariates and tumor subtypes (C-Index(full model), train[test]  =  0.72[0.71] ± 0.02 vs. C-Index(clinical + subtype model), train[test]  =  0.62[0.62] ± 0.02; p<10(-6)). In addition, the full model containing 19 CNIs significantly improved prognostication separately for ER-, HER2+, luminal B, and triple negative tumors over clinical variables alone. In summary, we show that a set of 19 CNIs discriminates risk of recurrence among early-stage breast tumors, independent of ER status. Further, our data suggest the presence of specific CNIs that promote and, in some cases, limit tumor spread.

Traditional factors currently used for prognostic stratification do not always adequately predict treatment response and disease evolution in advanced breast cancer patients. Therefore, the use of blood-based markers, such as circulating tumor cells (CTCs), represents a promising complementary strategy for disease monitoring. In this retrospective study, we explored the role of CTC counts as predictors of disease evolution in breast cancer patients with limited metastatic dissemination.

Obesity increases the risk of cancer death among postmenopausal women with estrogen receptor-positive (ER+) breast cancer, but the direct evidence for the mechanisms is lacking. The purpose of this study is to demonstrate direct evidence for the mechanisms mediating this epidemiologic phenomenon.