Abstract P6-05-08: LINC02273 interacts with hnRNPL and promotes metastasis through directly activating AGR2 in breast cancer

The prognosis of breast cancer patients with metastasis is still poor even improved by current treatment modalities. Unveiling new biomarkers and molecular mechanisms that underlie metastasis are of vital importance for the treatment of breast cancer. The recent discovery of long noncoding RNAs (lncRNAs) has gained widespread attention. To identify critical lncRNAs that contributed to breast cancer metastasis, we profiled their expression in 5 pairs of primary tumors and lymph nodes metastasis loci by HTA2.0 microarray. LINC02273 is significantly upregulated in metastasis loci and its high expression is associated with poor diseases free survival in a validation set of 254 patients. LINC02273 was mainly located in the cell nucleus . RACE-PCR showed two isoforms and the longest one was the most abundant isoform in breast cancer. Through transwell assay, 3D spheroid invasion assay and mice xenograft metastasis model, we found that LINC02273 promoted breast cancer cell migration, invasion and metastasis. Via mass spectrometry, hnRNPL was found to interact with LINC02273 to enhance its stability, which was further confirmed by Actinomycin D inhibition assay and luciferase reporter assay. Furthermore, ChIRP-seq and ChIP-seq showed that LINC02273 stimulated oncogene AGR2 expression by directly binding to the AGR2 promoter region and increasing H3K27ac modification. Triplex formation assay was performed for verification. We demonstrated that the expression level and oncogenic ability of AGR2 were regulated by hnRNPL through LINC02273. Clinical data and mouse xenograft tumors also revealed the positive correlation of AGR2 and LINC02273. In conclusion, LINC02273, which is stabilized by hnRNPL can promote breast cancer metastasis through upregulation of AGR2 and may serve as a prognostic biomarker for breast cancer.

Citation Format: Xiu B, Chi Y, Ji W, Zhang Q, Wu J. LINC02273 interacts with hnRNPL and promotes metastasis through directly activating AGR2 in breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-05-08.

Abstract P3-13-09: Increased mortality with repeat lumpectomy alone after ipsilateral breast tumor recurrence: A propensity-adjusted, population-based SEER analysis

Background: The benefit of repeat lumpectomy for ipsilateral breast tumor recurrence (IBTR) after breast conserving surgery (BCS) is currently inconclusive. This issue has become even more important as small and isolated recurrent tumors were frequently diagnosed.

Methods: IBTR patients with definitive surgery were identified in the Surveillance, Epidemiology, and End Results registry between 1973 and 2013. The effect of different IBTR surgeries on overall and cancer-specific mortality was assessed using risk-adjusted Cox proportional hazard regression modeling and stratified propensity score matching analysis (PSMA).

Results: Based on the selection criteria, 5098 patients were recruited. Of those, 4048 (79.4%) women underwent mastectomy and 1050 (20.1%) underwent repeat lumpectomy after IBTR. Patients who received repeat lumpectomy had lower grade (23.7% vs 15% for well-differentiated) and smaller recurrent tumor (47% vs 36.2% for ≤ 1 cm) but earlier recurrence (23.9% vs 11.2% for interval times < 48 months) than those who underwent mastectomy. A minority of each group (24.7% of those undergoing repeat lumpectomy and 3% of the mastectomy group) underwent RT after surgery. In multivariable Cox regression analysis, repeat lumpectomy was associated with increased overall mortality (Hazard ratio (HR) = 1.58, 95% CI = 1.353 to 1.844, P < 0.001) and cancer-specific mortality (HR = 1.721, 95% CI = 1.345 to 2.202, P< 0.001). Similar HRs were derived from the PSMA cohort. However, we found no significant difference in overall mortality for women who underwent repeat lumpectomy followed by RT compared with that for those who underwent mastectomy (P= 0.411). Moreover, IBTR patients with small tumors (≤ 1 cm) who underwent repeat lumpectomy with RT rather than without had similar overall and cancer-specific survival rates to those who underwent mastectomy (P= 0.189 and P= 0.604, respectively).

Conclusions: Our investigation suggests that compared with mastectomy, repeat lumpectomy for IBTR is associated with higher overall and cancer-specific mortality under real-world observational conditions. Furthermore, repeat lumpectomy with RT is equivalent to mastectomy with respect to overall mortality and may influence treatment decision making for patients with small IBTR.

Citation Format: Su Y, Guo R, Xue J, Chi Y, Wu J. Increased mortality with repeat lumpectomy alone after ipsilateral breast tumor recurrence: A propensity-adjusted, population-based SEER analysis [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-13-09.

Abstract P5-03-13: ERVMER34 sensitizes the response of HER2 positive breast cancer to neoadjuvant therapy

Although anti-HER2/neu antibody therapy combined with chemotherapy has achieved an outstanding effect, many patients with HER2-positive breast cancer still succumb due to therapeutic resistance. Understanding the mechanisms of therapeutic resistance is of vital importance. In this study, core needle biopsy tissue from HER2-positive patients was collected before neoadjuvant chemotherapy. Differentially expressed RNAs between pCR and non-pCR group have been identified through RNA-seq. Here we found that ERVMER34, an endogenous retroviral envelope protein was significantly inhibited in non-pCR group compared to pCR group. High ERVMER34 expression was associated with good overall survival both in TCGA database and our own patients cohort. Further study showed that ERVMER34 could be glycosylated and secreted to cell supernatant. The IC50 of paclitaxel and trastuzumab in HER2 positive breast cancer cells was decreased by ectopic overexpression of ERVMER34. Furthermore, RNA-seq, FACS assay and western blot revealed that ERVMER34 could promote cell apoptosis and sensitize therapy response through inhibiting mTOR pathway in HER2 positive breast cancer cells. Via mass spectrometry, TRIM21, an E3 ligase was found to interact with ERVMER34 and promoted its ubiquitination degradation. Taken together, these data suggest that ERVMER34 may severve as a novel biomarker to predict therapy response in HER2 positive breast cancer.

Citation Format: Chi Y, Ji W, Xiu B, Zhang Q, Wu J. ERVMER34 sensitizes the response of HER2 positive breast cancer to neoadjuvant therapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-03-13.

Abstract P6-09-11: NFATC2 suppresses the metastatic cascade in breast cancer patients

For the patients with breast cancer, the pathological status of axillary lymph nodes is one of the most important predictor of prognosis. In recent years, the application of sentinel lymph node biopsy has provided us with an opportunity for the further study on the mechanism of lymph node metastasis in breast cancer. Through detailed pathological examination of sentinel lymph nodes, we can easily find patients who are in the early stage of lymph node metastasis - that is, the tumor cells from the primary tumor, invading the lymph nodes and successfully colonized, but not yet break through the lymph node microenvironment defense to the subsequent lymph node. It is the most important stage during lymph node metastasis.

In the present study, we selected the pairing samples from breast cancer patients with early stage lymph node metastasis to carry out differential genomics research. A total of 182 genes with significant function and involved in significant signal transduction pathways were obtained. Bioinformatics method was used to screen out the mRNA, microRNA and transcription factor in the process of lymph node metastasis of breast cancer. We investigated the role of activated T cells c2 (NFATC2) in the core transcription factors as a target for further clinical and basic research.

The expression of NFATC2 was detected in the tissue microarray prepared from 200 patients with primary breast cancer. After the median follow-up period of 89.5 months, it showed that the prognosis of patients with NFATC2 overexpression was significantly better than that of the control group (p = 0.022). We also measured the expression of NFATC2 in 50 pairs of breast cancer patients with lymph node metastasis. The results showed that the expression of NFATC2 in the primary tumor was significantly higher than that in the matched lymph node, suggesting that in patients with breast cancer, the down-regulate or deficiency of NFATC2 expression may be related with lymph node metastasis. We also attempted to add the expression of NFATC2 as a new parameter in the prediction model of lymph node metastasis based on preoperative clinical and pathological parameters. The area under the ROC curve obtained in the newly established model was 0.767, the expression state of NFATC2 had impact on the performance of the prediction model. Furthermore, when we removed the NFATC2 parameter, it could reduce the area under the ROC curve in the validation group, suggesting that the expression of NFATC2 in the primary tumor may be used as a predictor of the pathological state of axillary lymph nodes.

In vitro and in vivo experiments, we demonstrated that NFATC2 has a significant suppression effect on the proliferation, migration and invasion of breast cancer cells. The potential NFATC2-target genes were determined by RNAseq and Chipseq. Nine differentially expressed genes were found to be regulated by NFATC2 in the Chip-seq analysis and bound to the promoter region of the gene, whereas GRAMD3 and SRGAP2 in the subsequent validation showed a positive correlation with the expression of NFATC2, suggesting that the two genes are likely to have a positive regulatory relationship with NFATC2.

This study clarifies that NFATC2 may represent a therapeutic target for early metastasis breast cancer.

Citation Format: Xue J, Chi Y, Chen J, Wu J. NFATC2 suppresses the metastatic cascade in breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-09-11.

Mutation update and long-term outcome after treatment with active vitamin D3 in Chinese patients with pseudovitamin D-deficiency rickets (PDDR)

Pseudovitamin D-deficiency rickets is a rare disease which is caused by CYP27B1. In this study, we identified 9 mutations in 7 PDDR patients. In addition, we observed the response to long-term treatment of calcitriol in 15 Chinese patients with PDDR, which showed that the biochemical abnormalities had been corrected satisfactorily after 1-year treatment.

INTRODUCTION

Pseudovitamin D-deficiency rickets is a rare autosomal recessive disorder resulting from a defect in 25-hydroxyvitamin D 1α-hydroxylase, which is encoded by CYP27B1. The purpose of this study was to identify the CYP27B1 mutations and investigate the response to long-term treatment of calcitriol in Chinese patients with PDDR.

METHODS

We investigated CYP27B1 mutations in seven individuals from six separate families. To investigate the response to long-term (13 years) treatment with calcitriol in PDDR patients, we additionally collected clinical data of eight families from our previous report and analyzed their biochemical parameter and radiographic changes during the treatment.

RESULTS

Nine different mutations were identified: two novel missense mutations (G194R, R259L), three novel and one reported deletion mutations (c1442delA, c1504delA, c311-321del, and c. 48-60del), two novel nonsense mutations (c.85G>T, c.580G>T), and a reported insertion mutation (c1325-1332insCCCACCC). The statistical analysis revealed that parathyroid hormone (PTH) and ALP significantly decreased after 6-month and 1-year treatment with calcitriol respectively. Urine calcium was measured in all the patients without kidney stones being documented. After 6-year treatment, the radiographic abnormalities had also been improved. Two patients who had reached their final height are both with short stature (height Z-score below - 2.0).

CONCLUSIONS

We identified seven novel mutations of CYP27B1 gene in seven Chinese PDDR families. Our findings revealed after 1-year treatment of active vitamin D₃, PTH and ALP significantly decreased. The correction of the biochemical abnormalities had not improved the final height satisfactorily.

The functions of caspase in whitefly Bemisia tabaci apoptosis in response to ultraviolet irradiation

Whiteflies (Bemisia tabaci) are phloem feeders, and some invasive species are composed of cryptic species complexes that cause extensive crop damage, particularly via the direct transmission of plant viruses. Apoptosis is a type of programmed cell death essential for organismal development and tissue homeostasis. The caspases belong to a family of cysteine proteases that play a central role in the initiation of apoptosis in many organisms. Here, we employed a comprehensive genomics approach to identity caspases in B. tabaci Middle East Asia Minor 1 (MEAM1), an invasive whitefly that carries a cryptic species complex that is devastating to crops. Four caspase genes were identified, and their motif compositions were predicted. Structures were relatively conserved in both putative effector and initiator caspases. Expression patterns of caspase genes differed across insect developmental stages. Three caspase genes were induced immediately after ultraviolet (UV) treatment. Expression levels of Bt-caspase-1 and Bt-caspase-3b increased in the midgut and salivary glands during apoptosis induced by UV treatments, whereas silencing of both genes reduced UV-triggered apoptosis. Our study demonstrates that Bt-caspase-1 and Bt-caspase-3b, respectively, act as putative initiator and effector apoptotic caspases in the MEAM1 whitefly.

Mutations in ORP1 Conferring Oxathiapiprolin Resistance Confirmed by Genome Editing using CRISPR/Cas9 in Phytophthora capsici and P. sojae

Oxathiapiprolin is a novel fungicide that was recently registered in a number of countries to control plant-pathogenic oomycetes such as Phytophthora capsici. In our previous study, point mutations G770V and G839W in oxysterol binding protein-related protein 1 (ORP1) were detected in oxathiapiprolin-resistant P. capsici isolates (PcORP1). Here, we used the CRISPR/Cas9 system to verify the effects of these two point mutations on P. capsici phenotypes. Transformants containing heterozygous G770V and G839W mutations in PcORP1 showed high levels of oxathiapiprolin resistance. The G770V transformants showed otherwise similar phenotypes compared with the wild-type isolate BYA5, including sporangia and zoospore production, cyst germination, and pathogenicity. However, two independent transformants with heterozygous G839W mutations in PcORP1 could not produce sporangia. Three transformants with an unexpected point mutation in PcORP1 (ΔN837) showed high oxathiapiprolin resistance, and either similar or significantly reduced fitness compared with BYA5. The same deletion (ΔN837) was confirmed to confer oxathiapiprolin resistance in P. sojae by using CRISPR/Cas9. These homozygous P. sojae mutants also showed either similar or strongly reduced fitness compared with the wild-type parent isolate P6497. These results improve our understanding of oxathiapiprolin resistance in Phytophthora spp., and will be useful for the development of novel oxysterol-binding protein homolog inhibitor fungicides.

Pseudoperonospora cubensis in China: Its sensitivity to and control by oxathiapiprolin

The novel fungicide oxathiapiprolin has potential for the control of downy mildew of cucumber, which is caused by Pseudoperonospora cubensis. In this study, an in vitro bioassay with detached leaves was used to determine the baseline sensitivity to oxathiapiprolin for 77 Ps. cubensis isolates from 11 provinces in China. The baseline sensitivity curve was continuous, and the average EC₅₀ value was 2.23 × 10^-4 μg ml^-1. In field trials, the control of downy mildew of cucumber was greater with oxathiapiprolin at 20 or 30 g a.i. ha^-1 than with dimethomorph at 262.5 g a.i. ha^-1. Oxathiapiprolin was taken up by cucumber roots and transported upwards to stems and leaves. The full length of PscORP1, the gene that encodes the target protein of oxathiapiprolin in Ps. cubensis, was sequenced for the first time. Our results suggested that oxathiapiprolin will be an excellent alternative fungicide for control of cucumber downy mildew. However, as Ps. cubensis is a high-risk pathogen, resistance development to oxathiapiprolin should be monitored and managed.

Abstract P5-07-05: LOC283299 suppress the lymphnode metastatic cascade in breast cancer patients

Background

Long non-coding RNAs (lncRNAs) have been proved to play an essential role in cancer metastasis. The accuracy of intraoperative assessment of lymph nodes metastasis need to be improved. In this study, we aimed to define the lncRNA biomarker ectopic expressed in breast cancer patients' metastatic lymph nodes, and to explore the potential molecular mechanisms.

Experimental Design

RNA-seq analyses in 3 paired breast cancer patients' primary tumor and metastatic lymph node was used as training set to determine differentially expressed lncRNAs that may be associated with lymph node metastasis. The other 40 patients were analyzed as validation set to test the accuracy of lncRNAs identification by quantitative real-time PCR. The correlation between LOC283299 expression level and prognosis in other 282 breast cancer patients was confirmed. In parallel, in vitro and in vivo analyses were carried out to determine the potential mechanisms of LncRNA-dependent lymph node metastases and prognosis.

Results

RNA-seq analyses in the training set revealed significant correlation between high expression level of LOC283299 and lower lymph node metastasis potential in breast cancer patients. We further validated that the expression level of LOC283299 was significantly higher in tumor primary tissue than that in paired metastatic lymph node (P=0.0245), and higher LOC283299 expression level was markedly associated with good metastasis-free survival in breast cancer patients (P=0.04). In breast cancer cell lines, CRISPR-on overexpression of LOC283299 inhibited proliferation, migration, invasion, and metastases both in vivo and in vitro. shRNA knockdown LOC283299 promotes the ability of tumor proliferation and metastasis. The molecular mechanisms by which LOC283299 as metastasis-suppressing lncRNAs regulates recurrence and metastasis may involve regulation of epithelial to mesenchymal transition (EMT), cellular invasion and microenvironment in breast cancer cells.

Conclusion

Our study revealed a strong correlation between LOC283299 expression and lymph node metastases in breast cancers. High level of LOC283299 was associated with better metastasis-free survival. The changed metastasis phenotype may be mediated by the interaction of LOC283299 and breast cancer cells. Therefore, LOC283299 may represent a potential predictive biomarker for early lymph node metastasis in breast cancer.

Citation Format: Guo R, Xue J, Su Y, Xiu B, Ji W, Chi Y, Wu J. LOC283299 suppress the lymphnode metastatic cascade in breast cancer patients [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-07-05.

A new method to reconstruct intra-fractional prostate motion in volumetric modulated arc therapy

Intra-fractional motion is a concern during prostate radiation therapy, as it may cause deviations between planned and delivered radiation doses. Because accurate motion information during treatment delivery is critical to address dose deviation, we developed the projection marker matching method (PM³), a novel method for prostate motion reconstruction in volumetric modulated arc therapy. The purpose of this method is to reconstruct in-treatment prostate motion trajectory using projected positions of implanted fiducial markers measured in kV x-ray projection images acquired during treatment delivery. We formulated this task as a quadratic optimization problem. The objective function penalized the distance from the reconstructed 3D position of each fiducial marker to the corresponding straight line, defined by the x-ray projection of the marker. Rigid translational motion of the prostate and motion smoothness along the temporal dimension were assumed and incorporated into the optimization model. We tested the motion reconstruction method in both simulation and phantom experimental studies. We quantified the accuracy using 3D normalized root-mean-square (RMS) error defined as the norm of a vector containing ratios between the absolute RMS errors and corresponding motion ranges in three dimensions. In the simulation study with realistic prostate motion trajectories, the 3D normalized RMS error was on average [Formula: see text] (range from [Formula: see text] to [Formula: see text]). In an experimental study, a prostate phantom was driven to move along a realistic prostate motion trajectory. The 3D normalized RMS error was [Formula: see text]. We also examined the impact of the model parameters on reconstruction accuracy, and found that a single set of parameters can be used for all the tested cases to accurately reconstruct the motion trajectories. The motion trajectory derived by PM³ may be incorporated into novel strategies, including 4D dose reconstruction and adaptive treatment replanning to address motion-induced dose deviation.

S-1 chemotherapy and intensity-modulated radiotherapy after D1/D2 lymph node dissection in patients with node-positive gastric cancer: a phase I/II study

BACKGROUND

This phase I/II clinical trial investigated S-1 administered with intensity-modulated radiotherapy (IMRT) as adjuvant therapy for node-positive gastric cancer. Patients had undergone radical resection and D1/D2 lymph node dissection.

METHODS

In phase I, patients received adjuvant chemoradiotherapy of IMRT (45 Gy in 25 fractions) with concurrent S-1 administered on a dose-escalation schedule to determine the recommended dose (RD). In phase II, the safety and efficacy of the RD of S-1 combined with IMRT were assessed.

RESULTS

We consecutively enrolled 73 patients (56 men; median age, 53 years; range, 29-73 years) and the phase I portion of the study included 27 patients. The RD of S-1 administered concomitantly with IMRT was 80 mg m^-2 day^-1 orally, twice daily. The phase II analysis included 52 patients (46 new patients plus 6 from phase I). 8 patients (15.4%) developed grade 3 or 4 toxicities. There were 21 recurrence events and 15 deaths (1 bowel obstruction, 14 gastric cancer). Three-year disease-free survival and overall survival were 62.2% (95% confidence interval (CI), 48.5-75.9) and 70.0% (95% CI, 56.3-83.7), respectively. The median time to recurrence was 17.5 months (range, 3.8-42.0). The median time from recurrence to death was 7.0 months (range, 1.5-28.7).

CONCLUSIONS

S-1 combined with IMRT adjuvant chemoradiotherapy is safe and efficacious for advanced gastric cancer.

Stenosis detection and quantification on cardiac CTCA using panoramic MIP of coronary arteries

In this work, we proposed to demonstrate the entire 3D coronary tree using panoramic maximum intensity projection (MIP) of coronary arteries, and to detect and quantify coronary stenosis from computed tomography coronary angiography (CTCA). The performance of the proposed method was assessed in comparison with invasive coronary angiography (ICA) as reference standard. Six anonymized CTCA datasets were tested. MIP method achieved a sensitivity of 82% and a specificity of 95% for the stenosis detection with a good reproducibility (i.e. Cohen's kappa coefficient of 0.74 for the intra-rater agreement, and 0.45 for the inter-raters agreement). In stenosis quantification, three image options are provided. The original density images resulted in an accuracy of 0.85. The edge map images resulted in an accuracy of 0.79. The image combination had a better accuracy of 0.89 than any single image option. In conclusion, the panoramic MIP provided fast and accurate way for the stenosis detection and quantification. It may be helpful to assist the radiologist in identifying the location of the greatest narrowing in clinical practice.

The beam energy feedback system for Beijing electron positron collider II linac

A beam-energy feedback system has been developed for the injection linac to meet the beam quality needed for the Beijing electron positron collider II storage ring. This paper describes the implementation and commissioning of this system in detail. The system consists of an energy measurement unit, application software, and an actuator unit. A non-intersecting beam energy monitor was developed to allow real-time online energy adjustment. The beam energy adjustment is achieved by adjusting the output microwave phase of the RF power source station. The phase control mechanism has also been modified, and a new control method taking the return difference of the phase shifter into account is used to improve the system's performance. This system achieves the design aim and can adjust the beam center energy with a rate of 2 Hz. With the energy feedback system, the stability of the injection rate is better; the fluctuation range is reduced from 20 mA/min to 10 mA/min, while the stability of the beam center energy is maintained within ±0.1%.