Abstract 5514: Analysis of immune checkpoint receptor expression by circulating T cells and tumor specimens in patients pre- and post-neoadjuvant chemotherapy for operable breast cancer

While combinations of immune checkpoint (ICP) inhibitors and neo-adjuvant chemotherapy (NAC) have begun to be tested in patients with breast cancer (BC), chemotherapeutic effects on ICP expression in circulating T cells are still unclear. This information could help design future clinical trials including the selection of the best ICP inhibitors to be incorporated into NAC and finding predictive/prognostic biomarkers. Peripheral blood samples and/or tumor specimens before and after NAC were obtained from twenty-four women with operable BC. Using flow cytometry, the expression of CTLA4, PD-1, Lag3, OX40, and Tim3 on circulating T lymphocytes before and at the end of NAC were measured. Differences in the percentage of CD4+ and CD8+ T cells expressing various checkpoint receptors pre- and post-NAC were determined by a paired t-test. This data showed decreased ICP expression after NAC by circulating CD4+ T cells, including significant decreases in CTLA4 (p<0.001), Lag3 (p<0.001), OX40 (p<0.001), and PD-1 (p<0.001). In comparison, circulating CD8+ T cells showed a significant increase in CTLA4 (p<0.003), Lag3 (p=0.001), and OX40 (p<0.001). In comparing breast cancer subtypes, it was found there were significantly lower amounts of circulating Lag3+ CD4+ T cells from triple-negative (lacking estrogen, progesterone, and HER2 receptor expression) breast cancer patients than those from breast cancer patients with tumors expressing at least one of these receptors. Furthermore, using multi-color immunohistochemistry (IHC), the expression of stromal tumor infiltrating lymphocytes (TILs), CD8+ T cells, and PD-1/PD-L1 within the tumor were determined before and after NAC. This analysis revealed fewer tumor specimens were considered to be PD-L1/PD-1 positive post-NAC as compared to pre-NAC biopsy samples using a cutoff of 1% or greater expression. Overall, this work reveals that NAC has opposing effects on ICP expression by CD4+ and CD8+ T cells as well as provides a starting point to study the biological significance of these changes in BC patients.Trial registration: NCT04022616

Citation Format: Dionisia M. Quiroga, Andrew Stiff, Christopher McQuinn, Zaibo Li, Hiroaki Nitta, Himanshu Savardekar, Brooke Benner, Bhuvaneswari Ramaswamy, Maryam Lustberg, Rachel Layman, Erin Macrae, Mahmoud Kassem, Nicole Williams, Sagar Sardesai, Jeffrey VanDeusen, Daniel Stover, Mathew Cherian, Thomas Mace, Lianbo Yu, Megan Duggan, William E. Carson, Robert Wesolowski. Analysis of immune checkpoint receptor expression by circulating T cells and tumor specimens in patients pre- and post-neoadjuvant chemotherapy for operable breast cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5514.

Phase I Study of Veliparib on an Intermittent and Continuous Schedule in Combination with Carboplatin in Metastatic Breast Cancer: A Safety and [18F]-Fluorothymidine Positron Emission Tomography Biomarker Study

BACKGROUND

Poly(ADP-ribose) polymerase inhibitors (PARPis) are U.S. Food and Drug Administration (FDA) approved for treatment of BRCA-mutated metastatic breast cancer. Furthermore, the BROCADE studies demonstrated benefit of adding an oral PARPi, veliparib, to carboplatin and paclitaxel in patients with metastatic breast cancer harboring BRCA mutation. Given multiple possible dosing schedules and the potential benefit of this regimen for patients with defective DNA repair beyond BRCA, we sought to find the recommended phase II dose (RP2D) and schedule of veliparib in combination with carboplatin in patients with advanced breast cancer, either triple-negative (TNBC) or hormone receptor (HR)-positive, human epidermal growth receptor 2 (HER2) negative with defective Fanconi anemia (FA) DNA-repair pathway based on FA triple staining immunofluorescence assay.

MATERIALS AND METHODS

Patients received escalating doses of veliparib on a 7-, 14-, or 21-day schedule with carboplatin every 3 weeks. Patients underwent [18]fluoro-3'-deoxythymidine (¹⁸ FLT) positron emission tomography (PET) imaging.

RESULTS

Forty-four patients (39 TNBC, 5 HR positive/HER2 negative with a defective FA pathway) received a median of 5 cycles (range 1-36). Observed dose-limiting toxicities were grade (G) 4 thrombocytopenia (n = 4), G4 neutropenia (n = 1), and G3 akathisia (n = 1). Common grade 3-4 toxicities included thrombocytopenia, lymphopenia, neutropenia, anemia, and fatigue. Of the 43 patients evaluable for response, 18.6% achieved partial response and 48.8% had stable disease. Median progression-free survival was 18.3 weeks. RP2D of veliparib was established at 250 mg twice daily on days 1-21 along with carboplatin at area under the curve 5. Patients with partial response had a significant drop in maximum standard uptake value (SUV_max ) of target lesions between baseline and early in cycle 1 based on ¹⁸ FLT-PET (day 7-21; p_trend  = .006).

CONCLUSION

The combination of continuous dosing of veliparib and every-3-week carboplatin demonstrated activity and an acceptable toxicity profile. Decrease in SUV_max on ¹⁸ FLT-PET scan during the first cycle of this therapy can identify patients who are likely to have a response.

IMPLICATIONS FOR PRACTICE

The BROCADE studies suggest that breast cancer patients with BRCA mutation benefit from addition of veliparib to carboplatin plus paclitaxel. This study demonstrates that a higher dose of veliparib is tolerable and active in combination with carboplatin alone. With growing interest in imaging-based early response assessment, the authors demonstrate that decrease in [18]fluoro-3'-deoxythymidine positron emission tomography (FLT-PET) SUV_max during cycle 1 of therapy is associated with response. Collectively, this study established a safety profile of veliparib and carboplatin in advanced breast cancer while also providing additional data on the potential for FLT-PET imaging modality in monitoring therapy response.

Exploratory analysis of immune checkpoint receptor expression by circulating T cells and tumor specimens in patients receiving neo-adjuvant chemotherapy for operable breast cancer

BACKGROUND

While combinations of immune checkpoint (ICP) inhibitors and neo-adjuvant chemotherapy (NAC) have begun testing in patients with breast cancer (BC), the effects of chemotherapy on ICP expression in circulating T cells and within the tumor microenvironment are still unclear. This information could help with the design of future clinical trials by permitting the selection of the most appropriate ICP inhibitors for incorporation into NAC.

METHODS

Peripheral blood samples and/or tumor specimens before and after NAC were obtained from 24 women with operable BC. The expression of CTLA4, PD-1, Lag3, OX40, and Tim3 on circulating T lymphocytes before and at the end of NAC were measured using flow cytometry. Furthermore, using multi-color immunohistochemistry (IHC), the expression of immune checkpoint molecules by stromal tumor-infiltrating lymphocytes (TILs), CD8+ T cells, and tumor cells was determined before and after NAC. Differences in the percentage of CD4+ and CD8+ T cells expressing various checkpoint receptors were determined by a paired Student's t-test.

RESULTS

This analysis showed decreased ICP expression by circulating CD4+ T cells after NAC, including significant decreases in CTLA4, Lag3, OX40, and PD-1 (all p values < 0.01). In comparison, circulating CD8+ T cells showed a significant increase in CTLA4, Lag3, and OX40 (all p values < 0.01). Within tumor samples, TILs, CD8+ T cells, and PD-L1/PD-1 expression decreased after NAC. Additionally, fewer tumor specimens were considered to be PD-L1/PD-1 positive post-NAC as compared to pre-NAC biopsy samples using a cutoff of 1% expression.

CONCLUSIONS

This work revealed that NAC treatment can substantially downregulate CD4+ and upregulate CD8+ T cell ICP expression as well as deplete the amount of TILs and CD8+ T cells found in breast tumor samples. These findings provide a starting point to study the biological significance of these changes in BC patients.

TRIAL REGISTRATION

NCT04022616.

Endocrine Therapy for Hormone Receptor-Positive Metastatic Breast Cancer: American Society of Clinical Oncology Guideline

PURPOSE

To develop recommendations about endocrine therapy for women with hormone receptor (HR) -positive metastatic breast cancer (MBC).

METHODS

The American Society of Clinical Oncology convened an Expert Panel to conduct a systematic review of evidence from 2008 through 2015 to create recommendations informed by that evidence. Outcomes of interest included sequencing of hormonal agents, hormonal agents compared with chemotherapy, targeted biologic therapy, and treatment of premenopausal women. This guideline puts forth recommendations for endocrine therapy as treatment for women with HR-positive MBC.

RECOMMENDATIONS

Sequential hormone therapy is the preferential treatment for most women with HR-positive MBC. Except in cases of immediately life-threatening disease, hormone therapy, alone or in combination, should be used as initial treatment. Patients whose tumors express any level of hormone receptors should be offered hormone therapy. Treatment recommendations should be based on type of adjuvant treatment, disease-free interval, and organ function. Tumor markers should not be the sole criteria for determining tumor progression; use of additional biomarkers remains experimental. Assessment of menopausal status is critical; ovarian suppression or ablation should be included in premenopausal women. For postmenopausal women, aromatase inhibitors (AIs) are the preferred first-line endocrine therapy, with or without the cyclin-dependent kinase inhibitor palbociclib. As second-line therapy, fulvestrant should be administered at 500 mg with a loading schedule and may be administered with palbociclib. The mammalian target of rapamycin inhibitor everolimus may be administered with exemestane to postmenopausal women with MBC whose disease progresses while receiving nonsteroidal AIs. Among patients with HR-positive, human epidermal growth factor receptor 2-positive MBC, human epidermal growth factor receptor 2-targeted therapy plus an AI can be effective for those who are not chemotherapy candidates.

Abstract P4-09-18: Characterization of circulating myeloid derived suppressor cells and cytokines in patients undergoing neo-adjuvant chemotherapy for breast cancer

Myeloid derived suppressor cells (MDSC) are immature immune cells that expand in patients (pts) with cancer and suppress anti-tumor immunity. MDSC are also known to support angiogenesis. Higher circulating MDSC levels are seen in patients with greater tumor burden. Therefore, circulating MDSC levels could be affected by chemotherapy and could correlate with response. In this prospective pilot trial, peripheral blood (PB) levels of granulocytic (G-MDSC) and monocytic (M-MDSC) MDSC were measured in pts with operable breast cancer (BC) treated with neo-adjuvant chemotherapy (NAC) to study their association with pathologic complete response. It was hypothesized that MDSC % would show an association with complete pathologic response (pCR). The association of 10 different cytokine levels (IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, IL-13, IFN-γ, TNF-α) with pCR was also explored. Linear mixed models tested the associations between MDSC % or cytokines across time points with pCR. Levels of MDSC were measured by flow cytometry as a % of PB mononuclear cells prior to cycle (C) 1 and 2 of doxorubicin and cyclophosphamide (AC) and 1st and last administration of paclitaxel (T) or T and anti-HER2 therapy (in HER2+ pts). For other regimens, MDSC were measured prior to 1st, 2nd and last cycle. MDSC were defined as HLA-DR-, CD11b+, CD33+ cells with G-MDSC and M-MDSC cells expressing CD15 and CD14, respectively. Plasma cytokine levels were measured using a multiplex assay (Bio-Rad). Of 24 enrolled pts, 1, 20 and 3 had clinical stage I, II, IIIA, respectively. Median age was 48 (range 32-70). 11, 6 and 7 pts were triple negative (TN), HER2+ and hormone receptor (HR)+, respectively. PCR rate was 45.8% (46%, 50%, 43%, 20% for TN, HER2+, HR+ and &gt;10% HR+ pts). Rate of residual cancer burden (RCB) class 0-1 was 58.3% (63.6%, 50%, 57.1%, 40% in TN, HER2+, HR+ and &gt;10% HR+ pts). Mean M-MDSC % were &lt;1 at all time points. Mean G-MDSC % and 95% confidence intervals (CI) were 0.88 (0.23-1.54), 5.07 (2.45-7.69), 9.32(4.02-14.61) and 1.97 (0.53-3.41) at times 1-4. The increase in MDSC by C1 of T was significant (p&lt;0.0001) in all BC types. Baseline G-MDSC % did not differ in pts with or without pCR. G-MDSC levels at the last time point were also not statistically different but were numerically slightly lower in pts with pCR (1.15; 95%CI 0.14-2.16) versus pts with no pCR (2.71; 95%CI 0-5.47). Levels of all 10 cytokines were measurable in pts throughout NAC. The mean levels of IL-1β, IL-2, IL-4, IL-13 and IFN-γ peaked by C1 of T, while levels of IL-5, IL-6, IL-10, IL-12 and TNF-α were the highest at draw 1 and decreased during NAC. This pilot study confirmed feasibility of measuring circulating MDSC and cytokines in breast cancer pts receiving neo-adjuvant chemotherapy. The results showed that G-MDSC % increase during AC and then decrease during T and that a mixture of Th1 and Th2 cytokines peak during treatment. Levels of MDSC and cytokines did not significantly differ between pts with or without a pCR. However, a larger study with greater power to detect smaller differences and evaluate association between MDSC levels and pCR in different BC subtypes is needed.

Citation Format: Wesolowski R, Duggan M, Stiff A, Trikha P, Schoenfield L, Abdel-Rasoul M, Layman R, Ramaswamy B, Macrae E, Lustberg MB, Mrozek E, Carson WE. Characterization of circulating myeloid derived suppressor cells and cytokines in patients undergoing neo-adjuvant chemotherapy for breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-09-18.

Abstract P1-09-03: Prevention of aromatase Inhibitor (AI)-induced joint symptoms with omega-3 fatty acid supplementation: A randomized placebo-controlled pilot study

Introduction: AI-induced joint symptoms negatively impact drug adherence and quality of life. Based on observations that n-3 polyunsaturated fatty acids (PUFAs) have anti-inflammatory effects and that the mechanism of AI-induced joint symptoms may be partly due to inflammation, we hypothesized that women taking more n-3 PUFAs are less likely to develop AI-induced joint symptoms.

Methods: We conducted a randomized, double-blind, placebo-controlled study comparing n-3 PUFA vs placebo in postmenopausal breast cancer patients starting adjuvant AIs. Participants were randomized to n-3 supplements [2.58 g eicosapentaenoic acid + 1.74 g docosahexaenoic acid/day; Marine Nutriceuticals, Mt. Bethel, PA] vs matched placebo for 24 weeks (wks). Primary endpoints was feasibility; secondary outcomes were self-reported symptoms as assessed by the Brief Pain Inventory short form (BPI-SF), Functional Assessment of Cancer Treatment, Breast & Endocrine Symptoms (FACTB-ES), and Stanford's Health Assessment and Disability Index (HAQ) at baseline prior to AI receipt, 12 and 24 wks. Compliance and toxicity were evaluated monthly. Serial peripheral blood n-3 PUFA levels and inflammatory cytokines (IL-6, TNFR2, IL-17) were drawn. MRI of hands/wrists was performed in selected patients using a 3 Tesla dedicated wrist coil at baseline and treatment end.

Results: Forty-four women were enrolled and randomized to study drug; 42 received ≥1 cycle (4 wks) of treatment; 36 had ≥1 post treatment evaluation at wk 12 or 24. Median age was 59.5 (range 43-76); history of prior taxane (n=15, 34%). The two groups’ baseline characteristics were similar. Overall, 93% and 88% of patients took &gt;80% of the placebo and n-3 PUFA doses, respectively. Baseline erythrocyte n-3 PUFA was similar for both groups (6.6% ± 1.6%, 7.2% ±1.9%, p=0.20), but higher in the n-3 PUFA arm by wk 24 (6.5%±1.0% vs 15.0%±3.3%, p&lt;0.001). Most toxicities were grade 1; the n-3 PUFA arm had only 1 (2.5%) grade 3 toxicity (diarrhea). The n-3 PUFA arm reported lower mean BPI-SF scores after treatment [(-.0.28/ -0.25 at week 12/24); but not statistically significant compared to placebo (p=0.494 and 0.601)]. Based on BPI-SF, the n-3 PUFA arm reported less interference of pain symptoms compared to placebo at 12 weeks (-.72, p=0.08). This arm also had a decreased walking, activity and working (WAW) score on BPI-SF at 12 weeks (-.81 p=0.05), and reported significantly greater pain relief from medications at 12 (p=0.043) and 24 weeks (p=0.011). Both arms had similar baseline and wk 24 serum IL-6 levels; levels decreased from baseline to wk 24 in the n-3 PUFA arm (-0.54±0.25, p=0.048). There was a non-significant trend (p= 0.2) toward decreased wrist inflammation by MRI imaging at 24 wks in the n-3 PUFA arm.

Conclusions: This is the first randomized pilot study to show that n-3 PUFA supplementation to prevent AI-induced joint symptoms is feasible and well tolerated. There is preliminary evidence that this intervention may help reduce the burden of AI-induced arthralgias.

OSU Study #11022; ClinicalTrials.gov Identifier: NCT01478477. Grants from the National Cancer Institute (CA037447-26) to the Alliance for Clinical Trials in Oncology supported this pilot study.

Citation Format: Maryam B Lustberg, Tonya Orchard, Xueliang Pan, Raquel Reinbolt, Amanda Logan, Joanne Lester, Rachel M Layman, Erin Macrae, Ewa Mrozek, Bhuvaneswari Ramaswamy, Robert Wesolowski, Michael Berger, Michael Knopp, Charles Loprinzi, Charles L Shapiro, Lisa Yee. Prevention of aromatase Inhibitor (AI)-induced joint symptoms with omega-3 fatty acid supplementation: A randomized placebo-controlled pilot study [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-09-03.

Abstract P4-01-02: Prospective characterization of HER2-positive circulating tumor cells in patients with HER2-negative metastatic breast cancer

Background: We have previously shown feasibility by CLIA validation of HER2 FISH on circulating tumor cells (CTCs). Several small retrospective studies have identified HER2 amplification in CTCs in a subset of patients (pts) with clinically HER2 negative metastatic breast cancer (MBC). While these findings potentially have profound implications for CTCs as a predictive biomarker, prospective validation and functional characterization of this subgroup is necessary.

Methods: We enrolled a prospective cohort of pts with MBC that was HER2 negative by IHC and/or FISH on all available primary and metastatic biopsies. Pts had ≥1 line of prior chemotherapy for MBC. Blood samples were collected at study entry. CTCs were enumerated based on standard criteria (Cytokeratin (CK)+/CD45- staining) as well as by FISH for HER2 using the OncoCEE-BR™ CTC test (Biocept, Incorporated). This test employs a proprietary antibody cocktail for capture followed by CK/CD45 staining, and FISH analysis directly within a microfluidic device. Samples were reported as positive if the HER2/CEP17 ratio was ≥ 2.0. HER2+ CTCs were classified into two categories: CK+/CD45-/HER2+ and CK-/CD45-/HER2-

Results: CTCs were observed in 208 out of 323 pts (64%). Median number of CTCs was 10 (range 1 to &gt; 34195). 75 pts (23%) had HER2+ CTCs, with a median number of 3 HER2+ CTCs (range 1 to 21). 36% (27/75) of these pts had CK+/HER2+ CTCs and 43% (32/75) of pts had only CK-/HER2+ CTCs. The remaining pts (21%) had both CK+/HER2+ and CK-/HER2+ CTCs present.

Conclusion: HER2 amplified CTCs are present in a subset (23%) of pts with clinically HER2-negative breast cancers. Interestingly, we observed a high prevalence of pts with only CK-/HER2 amplified CTCs (32 out of 323; 10%). The unique multi-antibody CTC capture method used here thus allows for detection of a prevalent population of CK-/HER2+ CTCs that may be largely undetected by other current adopted technologies. The functional significance of CK-/HER2+ and CK+/HER2+ CTCs in patients with clinically HER2 negative breast cancer is currently being evaluated in a prospective study with HER2-directed therapy.

Citation Format: Ian E Krop, Erin Macrae, Sarah R Galler, Farideh Bischoff, Romeo Fauni, Edgar Sales, Lan Huynh, Christine Mitchell, Trisky Clarin-Tamayo, Mark Anderson, Leslie Abad, Eric Winer. Prospective characterization of HER2-positive circulating tumor cells in patients with HER2-negative metastatic breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P4-01-02.

Abstract P1-09-04: Longitudinal evaluation of taxane-induced neuropathy in early stage breast cancer

Introduction

Chemotherapy-induced peripheral neuropathy (CIPN) is a dose-limiting toxicity of several chemotherapy drug classes, including taxanes. Peripheral neuropathies have been shown to lead to pain, falls, and difficulty in walking and performing activities of daily living in a variety of patient populations. Although the prevalence of CIPN has been noted in cancer patients, the development of self-reported symptoms, gait changes and balance changes during treatment have not been well explored to date. We hypothesized that the use of taxane-based chemotherapy will result in significant changes in spatiotemporal gait and balance parameters, as well as self-reported quality of life and function.

Methods

We characterized the alterations in gait and balance that occur in non-metastatic breast cancer patients during taxane chemotherapy. We evaluated (1) spatiotemporal gait parameters, including cadence and step length, and (2) balance parameters, including time-to-contact and 95% ellipse area, using each patient as her own control. Laboratory assessment of gait and balance was conducted at baseline and at completion of therapy in selected patients. We compared the natural history of changes in gait and balance parameters with changes in CIPN status as measured by validated patient reported outcomes, including EORTC QLQ-C30, CIPN-20, and Brief Pain Inventory Short Form (BPI-SF), and the Duke Activity Status Index (DASI). Time points included pre-chemotherapy, after each cycle of chemotherapy, and one month after the end of therapy to collect information on neuropathy, pain and functional capacity. The preliminary data were illustrated using individual plots; trend lines (changing over time) were based on least square means at each time point, which were estimated using the linear mixed models for repeated measures.

Results

To date, 15 patients with localized breast cancer have been enrolled; patient recruitment is ongoing. The median age is 42 years (range 25-67). Ten patients (67%) received weekly paclitaxel, 1 patient (7%) received paclitaxel every 2 weeks, and 4 patients (27%) received docetaxel every 3 weeks. Preliminary results with these 15 patients, based on least square means at each timepoint, showed trends in several parameters. As treatments progressed, patients tended to develop more difficulty in quiet balance and in their ability to actively shift weight in the sagittal and frontal planes. From the CIPN-20, they also tended to develop increased difficulty with sensory and motor systems. From the QLQ-C30, their global health status also tended to worsen. For most of these parameters, the largest changes were observed between the 2nd and 3rd treatments, though some changes were not observed until the 4th treatment. From the BPI-SF, no trends in pain symptoms or pain interference were observed within this preliminary cohort.

Conclusions

Gait and balance testing is feasible in the clinical setting. Preliminary observations suggest that balance, function and quality of life may all be affected by taxane therapy, even without pain symptoms. The findings of this study will enable us to better characterize the neurotoxic effect of taxanes and to ultimately test the effectiveness of preventative measures and interventions.

Funding by NCI R03CA182165-01.

Citation Format: Maryam B Lustberg, Scott Monfort, Janani Singaravelu, Raquel E Reinbolt, Xueliang Pan, Bhuvaneswari Ramaswamy, Rachel M Layman, Robert Wesolowski, Ewa Mrozek, Erin Macrae, Charles Shapiro, Robyn Patrick, Charles L Loprinzi, Ajit Chaudhari. Longitudinal evaluation of taxane-induced neuropathy in early stage breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-09-04.

Mitogen-activated protein kinase signaling controls basal and oncostatin M-mediated JUNB gene expression

The mitogen-activated protein kinase (MAPK) pathway is aberrantly activated in many human cancers, including breast cancer. Activation of MAPK signaling is associated with the increased expression of a wide range of genes that promote cell survival, proliferation, and migration. This report investigated the influence of MAPK signaling on the regulation and expression of JUNB in human breast cancer cell lines. JUNB has been associated with tumor suppressor and oncogenic functions, with most reports describing JUNB as an oncogene in breast cancer. Our results indicated that JUNB expression is elevated in MCF10A(met), SKBR3, and MDA-MB-231 human breast cancer cell lines compared to nontransformed MCF10A mammary epithelial cells. Increased RAS/MAPK signaling in MCF10A(met) cells correlates with the increased association of RNA polymerase II (Pol II) phosphorylated on serine 5 (Pol IIser5p) with the JUNB proximal promoter. Pol IIser5p is the "transcription initiating" form of Pol II. Treatment with U0126, a MAPK pathway inhibitor, reduces Pol IIser5p association with the JUNB proximal promoter and reduces JUNB expression. Oncostatin M (OSM) enhances MAPK and STAT3 signaling and significantly induces JUNB expression. U0126 treatment reduces OSM-induced Pol IIser5p binding to the JUNB proximal promoter and JUNB expression, but does not reduce pSTAT3 levels or the association of pSTAT3 with the JUNB proximal promoter. These results demonstrate that the MAPK pathway plays a primary role in the control of JUNB gene expression by promoting the association of Pol IIser5p with the JUNB proximal promoter.

Use and duration of chemotherapy in patients with metastatic breast cancer according to tumor subtype and line of therapy

Benefits of chemotherapy vary in patients with metastatic breast cancer (MBC). This article describes the impact of tumor subtype and the line of therapy on the duration of chemotherapy. Clinicopathologic characteristics were extracted from the medical records of 199 consecutive patients with MBC at Dana-Farber Cancer Institute and analyzed according to subtype. Tumor subtypes were classified as hormone receptor (HR)-positive, triple-negative (TNBC), or HER2-amplified breast cancer. Duration of chemotherapy of each line was defined as the start of a chemotherapy regimen to the start of the next line of therapy as a result of progression or toxicity. There were 96, 44, and 59 patients with HR(+), TNBC, and HER2-amplified breast cancer, respectively. Median age at MBC diagnosis was 53 years. Median overall survivals were 32 and 54 months for HER2-amplified disease, 36 months for HR(+) breast cancer, and 17 months for TNBC (P<.0001). Patients with HER2-amplified disease received the most lines (median, 4; P=.032) and the longest duration of chemotherapy for every line. The median duration of chemotherapy in HER2-amplified patients remained at more than 4 months even out to sixth-line therapy. Patients with TNBC tended to receive the shortest duration of chemotherapy for every line of therapy. Tumor subtypes influence the number of lines, duration of chemotherapy, and survival. Among patients with HR(+) and HER2-amplified disease who undergo chemotherapy beyond the third line, substantial rates of prolonged therapies suggest clinical benefit. The role of advanced (greater than third) chemotherapy lines in improving survival of all patients with MBC warrants further study.

Abstract P4-12-20: Clinical outcomes of patients with recurrent HER2-positive breast cancer after exposure to adjuvant trastuzumab

Background:

Trastuzumab has become the cornerstone of adjuvant therapy for patients with HER2-positive breast cancer, as it has significantly impacted on overall survival for these patients. Unfortunately, not all patients are cured, and recurrences occur in up to 13% of patients. In the post-trastuzumab era, long-term outcomes for HER2-positive breast cancer patients who develop recurrent disease after exposure to adjuvant trastuzumab is unknown.

Methods:

We retrospectively identified patients with stage I-III HER2-positive breast cancer treated at The Ohio State University Medical Center from 1995-2011. Patients were divided into two groups: those exposed to adjuvant trastuzumab, and those who never received adjuvant trastuzumab. Medical records were reviewed to obtain demographic data, disease status at diagnosis, adjuvant and metastatic therapeutic regimens, date and location of recurrent disease, date of last follow-up and vital status. Time-dependent analyses were carried out using Kaplan-Meier estimates.

Results:

Six hundred and sixty-two patients were initially identified and included in the analysis. Of the 374 patients who did not receive adjuvant trastuzumab, 96 patients had recurrence (26%). There were 288 patients who received adjuvant trastuzumab, with 33 patients developing relapse (11%). In the patients who received adjuvant trastuzumab and subsequently recurred, there was a higher incidence of CNS recurrence (n = 8; 24%) than those who did not receive adjuvant trastuzumab (n = 10; 10%). Those that received adjuvant trastuzumab also had fewer bone metastases (n = 3; 9%) than the patients who did not receive adjuvant trastuzumab (n = 29; 30%). There was no difference in overall survival in patients with metastatic progression after exposure to adjuvant trastuzumab compared to patients with metastatic HER2-positive breast cancer without prior adjuvant trastuzumab (p = 0.41). Of the 33 patients who relapsed after adjuvant trastuzumab, the majority received HER2-targeted therapy in the form of trastuzumab or lapatinib (n = 22; 67%). Eleven patients received trastuzumab-based therapy and 9 received lapatinib-based therapy. Two patients received the combination of trastuzumab and lapatinib. The remainder received cytotoxic therapy alone (n = 3; 9%), endocrine therapy (n = 1; 3%) or local therapy (surgery or radiation) (n = 4; 12%). Three patients received no therapy.

Conclusion:

There was no difference in overall survival for HER2-positive breast cancer patients who recur after adjuvant trastuzumab compared to metastatic patients without exposure to adjuvant trastuzumab. CNS disease as the first site of recurrence occured more frequently in patients who had received adjuvant trastuzumab than in those who were not previously exposed to trastuzumab. Continued HER2-targeted therapy after relapse on adjuvant trastuzumab was the regimen of choice in the first-line metastatic setting.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-12-20.

Carbohydrate metabolism during postharvest ripening in kiwifruit

Mature fruit (kiwifruit) of Actinidia deliciosa var. deliciosa (A. Chev.), (C.F.) Liang and Ferguson cv. Haywood (Chinese gooseberry) were harvested and allowed to ripen in the dark at 20° C. Changes were recorded in metabolites, starch and sugars, adenine nucleotides, respiration, and sucrose and glycolytic enzymes during the initiation of starch degradation, net starch-to-sucrose conversion and the respiratory climacteric. The conversion of starch to sucrose was not accompanied by a consistent increase in hexose-phosphates, and UDP-glucose declined. The activity of sucrose phosphate synthase (SPS) measured with saturating substrate rose soon after harvesting and long before net sucrose synthesis commenced. The onset of sugar accumulation correlated with an increase in SPS activity measured with limiting substrates. Throughout ripening, until sucrose accumulation ceased, feeding [(14)C] glucose led to labelling of sucrose and fructose, providing evidence for a cycle of sucrose synthesis and degradation. It is suggested that activation of SPS, amplified by futile cycles, may regulate the conversion of starch to sugars. The respiratory climacteric was delayed, compared with net starchsugar interconversion, and was accompanied by a general decline of pyruvate and all the glycolytic intermediates except fructose-1,6-bisphosphate. The ATP/ ADP ratio was maintained or even increased. It is argued that the respiratory climacteric cannot be simply a consequence of increased availability of respiratory substrate during starch-sugar conversion, nor can it result from an increased demand for ATP during this process.