Surgical Removal Of Primary Tumor Research Articles

Albumin-mediated molecular competition of supramolecular photosensitizers for NIR-II imaging-guided phototherapy

Heptamethine cyanines (Cy7) typically exhibit strong near-infrared (NIR) fluorescence signals when in monodisperse states, but their distinctive π-conjugated structure leads to limited solubility in aqueous solutions, ultimately resulting in inherent fluorescence self-quenching. Enhancing the fluorescence quantum yield of these agents within aqueous environments, in order to achieve high-resolution biological imaging, presents a significant challenge. Herein, a benzothiazole-based Cy7-derivative (Cy7-BTH) is developed, exhibiting unique H-aggregation properties in aqueous solutions. Bovine serum albumin (BSA) binds to Cy7-BTH (BSA@Cy7-BTH) to modulate its molecular stacking and energy transfer, boosting its fluorescence accompanied by bright NIR-II tail emission. The competitive binding alters the planarity of Cy7-BTH, restricting its intramolecular rotation, and simutaneously changes the conformation of BSA, leading to BSA@Cy7-BTH aggregation to form hierarchical-structured nanoparticles. Notably, the BSA@Cy7-BTH nanoparticles significantly enhanced photothermal response of Cy7-BTH while maintaining its controlled reactive oxygen species (ROS) generation, offering NIR-II imaging-guided surgical removal of primary tumors, and simultaneously inhibiting cancer cell metastasis by synergistic PDT/PTT dissection of metastatic tumor cells in sentinel lymph nodes (SLNs). This study provides an innovative but facile strategy for their potential clinical applications by precisely regulating the intermolecular competitive interactions of NIR theranostic agents.

FSP1 is a predictive biomarker of osteosarcoma cells’ susceptibility to ferroptotic cell death and a potential therapeutic target

Human osteosarcoma (OS) is a relatively rare malignancy preferentially affecting long body bones which prognosis is often poor also due to the lack of effective therapies. Clinical management of this cancer basically relies on surgical removal of primary tumor coupled with radio/chemotherapy. Unfortunately, most osteosarcoma cells are resistant to conventional therapy, with the undergoing epithelial-mesenchymal transition (EMT) giving rise to gene expression reprogramming, thus increasing cancer cell invasiveness and metastatic potential. Alternative clinical approaches are thus urgently needed. In this context, the recently described ferroptotic cell death represents an attractive new strategy to efficiently kill cancer cells, since most chemoresistant and mesenchymal-shaped tumors display high susceptibility to pro-ferroptotic compounds. However, cancer cells have also evolved anti-ferroptotic strategies, which somehow sustain their survival upon ferroptosis induction. Indeed, here we show that osteosarcoma cell lines display heterogeneous sensitivity to ferroptosis execution, correlating with the mesenchymal phenotype, which is consistently affected by the expression of the well-known anti-ferroptotic factor ferroptosis suppressor protein 1 (FSP1). Interestingly, inhibiting the activity or expression of FSP1 restores cancer cell sensitivity to ferroptosis. Moreover, we also found that: i) AKRs might also contribute to resistance; ii) NRF2 enhances FSP1 expression upon ferroptosis induction; while iii) p53 contributes to the regulation of FSP1 basal expression in OS cells.In conclusion, FSP1 expression can potentially be used as a valuable predictive marker of OS sensitivity to ferroptosis and as a new potential therapeutic target.

A surgically optimized intraoperative poly(I:C)-releasing hydrogel prevents cancer recurrence

Recurrences frequently occur following surgical removal of primary tumors. In many cancers, adjuvant therapies have limited efficacy. Surgery provides access to the tumor microenvironment, creating an opportunity for local therapy, in particular immunotherapy, which can induce local and systemic anti-cancer effects. Here, we develop a surgically optimized biodegradable hyaluronic acid-based hydrogel for sustained intraoperative delivery of Toll-like receptor 3 agonist poly(I:C) and demonstrate that it significantly reduces tumor recurrence after surgery in multiple mouse models. Mechanistically, poly(I:C) induces a transient interferon alpha (IFNα) response, reshaping the tumor/wound microenvironment by attracting inflammatory monocytes and depleting regulatory Tcells. We demonstrate that a pre-existing IFN signature predicts response to the poly(I:C) hydrogel, which sensitizes tumors to immune checkpoint therapy. The safety, immunogenicity, and surgical feasibility are confirmed in a veterinary trial in canine soft tissue tumors. The surgically optimized poly(I:C)-loaded hydrogel provides a safe and effective approach to prevent cancer recurrence.

NCOG-46. PERSONALIZED, PARCEL-GUIDED RTMS FOR NEURO-REHABILITATION AFTER TUMOR NEUROSURGERY: SAFETY AND PROOF OF CONCEPT

Abstract Deficits in neurological and psychocognitive function are common for patients who have undergone surgical removal of primary tumors. Repetitive Transcranial Magnetic Stimulation (rTMS) is an emerging non-invasive tool used for the treatment of neuropsychiatric disorders. We present a retrospective review of individualized, targeted rTMS in thirteen patients who presented with post-operative neurological deficits following craniotomy for tumor resection. Multiple cortical targets were selected based on the patient’s neurological disorder, the networks associated with the deficit, and anomalies in the functional connectivity of the patient’s brain as determined by machine-learning. TMS treatment was performed for 5 consecutive days. EuroQol quality of life (EQ-5D), functional extremity scales, and neuropsychiatric questionnaires related to the patient’s deficit were assessed prior to rTMS treatment, after treatment, and during follow-up. Five patients (38.5%) had glioblastomas; four patients (30.8%) had oligodendrogliomas; two patients (15.4%) had astrocytoma; one patient (7.7%) had ganglioglioma; and one patient (7.7%) had a pineal cyst. All thirteen patients reported significantly improved quality of life after rTMS treatment (p = 0.0065) and during follow-up (p = 0.0038) as compared to baseline. For patients with functional deficits, lower extremity functional scale (LEFS) was significantly improved one week after rTMS treatment (p = 0.0205). Upper extremity function scale (UEFS) showed non-significant trend in improvement after rTMS treatment (p = 0.0777). In the two patients who developed post-craniotomy depression, they showed a 26% and 88% reduction in depressive symptoms based on the Beck’s Depression Inventory (BDI) at two-month follow-up. These results suggest that the personalized, functional connectivity approach to rTMS target and treatment may be effective for patients with post-craniotomy functional impairments and neuropsychiatric disorders. This method of post-operative interventional neuro-rehabilitation is safe, noninvasive, and allows for the simultaneous treatment of multiple symptoms.

Increased lung metastasis with sevoflurane in breast cancer surgery is associated with VEGF and elevated vascular permeability by VEGF in a mouse model of human breast cancer.

e13060 Background: An on-going controversy is whether general anesthetics used in cancer surgery substantially influence the outcome of cancer patients. Thousands of cancer patients undergo surgery with hope of cure. However, postoperative metastasis remains a deadly disease that affects millions of lives, even with all the recent therapeutic advancements. Anesthesia is required for surgical resection of solid tumors and we have shown that general anesthetics substantially influences the process of breast cancer lung metastasis through increasing pulmonary permeability in animal models. Our previous study demonstrates that inhaled anesthetic sevoflurane used during resecting primary breast tumors promotes lung metastasis via IL6 pathway in syngeneic model of murine 4T1 breast cancer cells, compared with an intravenous anesthetic propofol. Methods: Xenograft model of human MDA-MB 231 breast cancer of spontaneous metastasis was utilized in this study to evaluate the effect of commonly used general anesthetics including sevoflurane and propofol on breast cancer lung metastasis and explore the potential mechanism. Results: In this study we show that the metastatic promoting effect of sevoflurane is associated with elevated secretion of VEGF and increased vascular permeability in xenograft model of human MDA-MB 231 breast cancer of spontaneous metastasis. Cytokine array profiling reveals that the mice receiving sevoflurane have increased levels of pro-angiogenic factor VEGF in serum and lung tissues. Sevoflurane enhances the expression level of VEGFR on HUVEC cells. Furthermore, sevoflurane disrupts endothelial monolayer in vitro and elevates pulmonary vascular permeability in vivo. The sevoflurane-promoted breast cancer lung metastasis is reversed by DC101, an antibody targeting mouse VEGFR-2. Conclusions: Our results show that the inhaled anesthetic sevoflurane during surgical removal of primary tumor alter the course of metastasis through regulating secretion of VEGF and associated vascular remodeling. The mechanistic study of general anesthetics on cancer cell metastasis establishes the causal link and could provide the potential therapeutic intervention and guide the clinical trials.

AKR1B10 as a Potential Novel Serum Biomarker for Breast Cancer: A Pilot Study.

BackgroundAldo-keto reductase 1B10 (AKR1B10) is a secretory protein that is upregulated in breast cancer.ObjectiveThis case-controlled pilot study evaluated the serum level of AKR1B10 in healthy women and patients with a localized or metastatic breast cancer.MethodsAKR1B10 levels were measured by ELISA and IHC in several patient cohorts.ResultsOur data showed that serum AKR1B10 was significantly elevated in patients with localized (6.72 ± 0.92 ng/ml) or metastatic (7.79 ± 1.13 ng/ml) disease compared to cancer-free healthy women (1.69 ± 0.17 ng/ml) (p<0.001); the serum AKR1B10 was correlated with its expression in tumor tissues, but not with the tumor burden, molecular subtypes or histological stages. After surgical removal of primary tumors, the serum AKR1B10 was rapidly decreased within 3 days and plateaued at a level similar to that of healthy controls in most patients. ROC curve analysis suggested the optimal diagnostic cut-off value of serum AKR1B10 at 3.456 ng/ml with AUC 0.9045 ± 0.0337 (95% CI 0.8384 – 0.9706), sensitivity 84.75% (95% CI 73.01% to 92.78%), and specificity 93.88% (95% CI 83.13% to 98.72%).ConclusionsThese data indicate the potential value of serum AKR1B10 as a biomarker of breast cancer.

Abstract P1-05-08: Targeting tumor heterogeneity and breast cancer metastasis through the metastatic microenvironment mediated epigenetic reprogramming

Abstract Targeting tumor heterogeneity and breast cancer metastasis through the metastaticmicroenvironment mediated epigenetic reprogrammingLi Yang and Jae Young So, Nicolas Skrypek, Anand Merchant, George Nelson, Howard H.Yang, Maxwell P. LeeNational Cancer Institute, National Institutes of Health, Bethesda, MD 20892Current cancer treatments are largely based on the genetic characterization of primarytumors and are ineffective for metastatic disease. There is lack of mechanistic understanding ashow cancer cells are selected and evolved to establish distant metastatic colonies. In addition,tumor heterogeneity and biomarker identification remain to be some of the most difficultchallenges in cancer treatment. In the current study, we discovered an increased DNAmethyltransferase 3B (DNMT3B) in metastatic nodules and in tumor cells with epithelia tomesenchymal (EMT) phenotype. Of great interest, high levels of DNMT3B were correlated withpoor clinical outcomes in multiple human breast cancer datasets. Mechanistically, DNMT3Balters multiple pathways including STAT3, NFkappaB, PI3K/Akt, beta-catenin, Notch signalingas well as EMT, which are critical for cancer cell survival, apoptosis, proliferation, invasion, andcolonization. We further identified PGE2 and IL6 as critical inflammatory mediators inDNMT3B induction. Importantly, targeting IL6 or PGE2 production reduced DNMT3Bexpression and improved chemo treatment or PD1 immune therapy. Furthermore, perioperative(surgical removal of primary tumors) targeting DNMT3B in combination with chemotherapymarkedly suppressed tumor recurrence and metastasis in preclinical mouse models for triplenegative breast cancer. Our studies identify DNMT3B as an important mechanism fortranscription regulation in tumor heterogeneity that is critical for tumor invasion and metastasis,thus suggesting a validated target for treating metastatic disease. Citation Format: Li Yang, Jae Young So, Nicolas Skrypek, Anand Merchant, George Nelson, Howard Yang, Maxwell Lee. Targeting tumor heterogeneity and breast cancer metastasis through the metastatic microenvironment mediated epigenetic reprogramming [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-05-08.

No Difference Among Inhaled Anesthetics on the Growth and Metastasis of Murine 4T1 Breast Cancers in a Mouse Model of Spontaneous Metastasis.

Objective: This study evaluates the effect of the commonly used inhaled anesthetics isoflurane, sevoflurane, and desflurane on the viability and migration of murine 4T1 breast cancer cells, the growth, and lung metastasis in a syngenetic model of spontaneous metastasis. Methods: The murine 4T1 breast cancer cells were exposed to isoflurane (2%), sevoflurane (3.6%), or desflurane (10.3%) for 3 h. Cell viability was measured using the MTT assay. The migratory capacity of 4T1 cells was assessed using a scratch assay after 24 h incubation. Female balb/c mice were subjected to orthotopic implantation of 4T1 cells under anesthesia with one of the inhaled anesthetics: 2% isoflurane, 3.6% sevoflurane, or 10.3% desflurane. Subsequently, resection of primary tumors was performed under the identical anesthetic used during implantation for 3 h. Three weeks later, the mice were euthanized to harvest lungs for ex vivo bioluminescent imaging and histological analysis. Blood was collected for serum cytokine assays by ELISA. Results: There was no difference in cell viability among isoflurane, sevoflurane, desflurane, and control groups (n = 180 for each group, P = 0.648). Sevoflurane but not isoflurane or desflurane significantly increased the migration of 4T1 cells compared to the control group (n = 18, P = 0.024). There was no difference in the growth of the orthotopically implanted primary tumors (n = 12 for the isoflurane group, n = 11 for the sevoflurane group, and for the desflurane group, P = 0.879). Surgical dissection of primary tumors in mice under anesthesia with isoflurane, sevoflurane, or desflurane led to no difference in lung metastasis following surgery (P = 0.789). No significant difference was observed among isoflurane, sevoflurane, and desflurane groups in the serum levels of IL-6 (P = 0.284), CCL-1 (P = 0.591), MCP-1 (P = 0.135), and VEGF (P = 0.354). Conclusion: Our study demonstrated that sevoflurane increased the migration of 4T1 breast cancer cells in vitro. Inhaled anesthetics isoflurane, sevoflurane, and desflurane had no difference on the growth of primary tumor and the lung metastasis of 4T1 cells in the mouse model of spontaneous metastasis with surgical removal of primary tumors.

Targeting DAMP-induced inflammation to prevent breast cancer metastasis and improve anti-tumor immunity

Abstract Biomarkers associated with systemic inflammation correlate with poor prognosis in cancer patients. Circulating cell-free DNA (cfDNA) is released passively and actively by both tumor cells and host cells and cfDNA levels in blood correlate with tumor burden in many tumor types. Notably, studies in breast cancer have shown that inhibition of cfDNA has a significant effect in reducing invasion and migration in vitro and metastatic disease in vivo. We have previously demonstrated that nucleic acid binding polymers (NABPs) bind and inhibit the proinflammatory effects of cfDNA in a murine model of pancreatic cancer. We observed that levels of cfDNA in blood increase with tumor burden in an orthotopic immunocompetent murine model of breast cancer. Moreover, treatment of mice with the NABP, PAMAM-G3, following surgical removal of primary tumor results in decreased lung metastasis. This decrease in lung metastasis is associated with reduction in the levels of cfDNA in blood. In addition, treatment of mice with NABPs in an intravenous experimental metastasis breast cancer model results in reduced seeding of tumor cells in lungs and lung metastasis. Analysis of immune infiltrates in lungs of PAMAM-G3- and control-treated mice demonstrates NABP-mediated transition of immune cell composition in lungs from innate to adaptive immune cells. Collectively, these data suggest that NABPs can be used to target cfDNA and inhibit DAMPs associated pathological inflammation. The use of NABPs is an innovative approach to treat cancer progression and metastasis, particularly in a clinical setting following standard of care surgical tumor resection. This work is funded by the Department of Defense Breast Cancer Research Program award (PI, Smita Nair).

Abstract A72: Exploring the role of miR-223 loss in mammary epithelial cell transformation

Abstract Despite novel treatment strategies and prevention, one of the major clinical challenges in breast cancer (BC) is the development of local and distant recurrences. These are linked not only to genetic and epigenetic alteration in cancer cells, but also to tumor-microenvironment and tumor-host crosstalk. In this context, surgical removal of primary tumor, inducing an inflammatory response and a wound healing process, may stimulate residual cancer cell survival, growth, and invasion. Radiotherapy, representing a standard care after surgery in BC, exerts its function by killing residual tumor cells and altering the local microenvironment. We have recently demonstrated that intraoperative radiotherapy strongly induced miR-223 expression that, by targeting EGF released in the peritumoral context, dampened the activation of EGFR/HER2 pathway, eventually resulting as a potent restrainer of residual cancer cell survival and growth. We also observed that miR-223 is highly expressed in normal mammary tissue, while all BC specimens analyzed expressed remarkably low levels. In line with these results, normal mammary epithelial cells of basal (HMEC) or luminal (BPEC) subtype expressed high levels of miR-223 compared to all tested BC cell lines. These data supported the possibility that loss of miR-223 expression could represent a common and possibly early event during mammary epithelial cell transformation. To explore this possibility, we transduced HMEC and BPEC cells using several oncogenes and tested the expression of miR-223. Transient expression of HER2, vSrc, and KRasG12D resulted in immediate drop of miR-223. Furthermore, to mimic oncogene-driven miR-223 down-modulation, we silenced its expression in HMEC and BPEC cells. Intriguingly, the loss of miR-223 per se induced the acquisition of transformed-like phenotypes, such as an increased proliferation in 2D-culture and a loss of polarized acinar structure with the formation of disorganized colonies in 3D-context. Interrogation of the TCGA BC dataset, comprising a large panel of normal and BC samples, confirmed our data and showed that, among all BC subtypes, miR-223 was particularly decreased in HER2+ and luminal BC. Notably, clustering HER2+ BC for miR-223HIGH/pY1068-EGFRLOW stratified patients with a significantly better overall survival. We thus explored the contribution of miR-223 in HER2-driven cell transformation. We overexpressed miR-223 in normal mammary epithelial cells and transformed them with HER2WT, ∆16HER2 (a particularly aggressive alternative splicing form of HER2), or HER2V659E (constitutively active form of HER2). Overexpression of miR-223 was able to efficiently counteract HER2-driven transformation, both in in vitro and in vivo models, not only in the presence of the WT oncogene, but also in the presence of the two aggressive mutants, the ∆16HER2 and HER2V659E. Altogether, our results indicate that loss or decreased expression of miR-223 may represent an early and common event during mammary epithelial cell transformation, contributing to loss of polarity and altering the maintenance of the differentiate phenotype, features profoundly linked to the tumorigenic process. Discovering the molecular mechanism by which miR-223 (and/or its targets) exerts their functions in cellular transformation and their possible interference in the tumor/stroma crosstalk may lead to identification of novel prognostic markers for early lesions and new promising therapeutic targets. Citation Format: Francesca Citron, Ilenia Segatto, Gian Luca Rampioni Vinciguerra, Gustavo Baldassarre, Barbara Belletti. Exploring the role of miR-223 loss in mammary epithelial cell transformation [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr A72.

Abstract 2899: Antitumor activity of CIGB-300, a peptide CK2 inhibitor, in breast cancer models

Abstract CK2 is a serine-threonine kinase that has been involved in growth, proliferation and cell apoptosis. CK2 has a constitutive expression and it has more than 300 substrates. In recent years, CK2 became an interesting target for anticancer therapies. Inhibition of CK2 showed antitumor activity in different types of cancer. Because breast cancer is one of the main tumor types in which CK2 is overexpressed, we focus on the effect of CK2 inhibition as a modulator of key features of breast cancer cell biology. The aim of the present study was to evaluate the role of inhibition of CK2 by CIGB-300 in murine and human mammary carcinoma cell lines. For this purpose, we evaluated the action of CIGB-300 on viability, apoptosis, cell cycle, clonogenic capacity and migration using three different breast tumor cell lines, MCF7 (positive for estrogen, progesterone and HER2-neu receptors), MDA MB 231 (representative of triple negative tumors) and F3II, a murine mammary carcinoma. As compared the potential of CK2 inhibition in these models we included another chemical inhibitor of the enzyme, CX-4945. Our results showed that CIGB-300 reduced the viability of MDA MB 231 (IC50=120 μM) and MCF-7 (IC50=140 μM) (p&amp;lt;0.05, ANOVA). We observed that in both human and murine cell lines CIGB-300 exerts a pro-apoptotic action (TUNEL assay, p&amp;lt;0.05, χ2) and arrest cell cycle. We also found that the inhibition of CK2 by CIGB-300 decreased the clonogenic capacity and migration of F3II, MCF-7 and MDA-MB-231 (p&amp;lt;0.05, ANOVA). In vivo studies using the syngeneic F3II breast cancer model in BalB/c mice showed a decrease in the number of lung metastases in mice treated systemically with CIGB-300 after primary tumor surgery (Mann Whitney test, p&amp;lt;0.05). However, CK2 inhibition did not affect the growth of local recurrences. Also, intravenous administration of CIGB-300 decreased lung metastasis development of F3II cells. These results demonstrate an antimetastatic effect of CIGB-300 in a systemic inoculation model after surgical removal of primary tumors. In this work we demostrated the antitumor effect of CIGB-300 in breast cancer models such as those reported in myeloid leukemia, lung and cervix and head cancer. Citation Format: Maria F. Gottardo, Carla S. Capibianco, Johanna E. Sidabra, Yasser Perera, Silvio Perea, Daniel F. Alonso, Hernan G. Farina. Antitumor activity of CIGB-300, a peptide CK2 inhibitor, in breast cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2899.

Survival Benefit of Surgical Removal of Primary Tumor in Patients With Stage IV Breast Cancer

BackgroundSeveral studies have suggested that primary tumor removal improved overall survival for patients with stage IV breast cancer. However, the survival benefit of local treatment remains controversial. The purpose of the present study was to determine whether surgical removal of the primary tumor provides survival benefits to patients with stage IV breast cancer. Patients and MethodsWe retrospectively reviewed the medical records of 155 patients with an initial diagnosis of stage IV breast cancer at Seoul National University Bundang Hospital from 2003 to 2014. Kaplan-Meier analysis was used to estimate the median survival. The log-rank test was used to compare differences in patient and tumor characteristics. Multivariate Cox regression analysis for survival was used, controlling for potential confounding variables. ResultsOf 155 patients with stage IV breast cancer, 95 (61%) underwent surgical removal of the primary tumor. The median follow-up period was 59 months (95% confidence interval [CI], 45-73 months). The median survival was longer for the patients with a better response to chemotherapy (70 vs. 47 months; P = .010) and for those who had undergone surgery (118 vs. 28 months; P < .001) than for those who without a better chemotherapy response or surgery. The median survival of the patients who received radiotherapy was better than that of the patients who did not (65 vs. 39 months; P = .004). Patients with luminal A cancer had a median survival of 118 months, the longest compared with those with other subtypes (P = .001). In addition, patients with distant metastasis at a single site had a longer median survival than did those with multiple metastatic sites. The multivariate Cox regression analysis revealed that fewer distant metastases, surgery of the primary tumor, a better response to chemotherapy, and luminal A subtype were significant independent predictors of survival. ConclusionOur results showed that primary tumor removal was independently associated with improvement in survival. Therefore, surgical management for the primary tumor could be considered more actively in patients with stage IV breast cancer.

Anti-tumor effects of cold atmospheric pressure plasma on vestibular schwannoma demonstrate its feasibility as an intra-operative adjuvant treatment.

Vestibular schwannoma (VS), although a benign intracranial tumor, causes morbidities by brainstem compression. Since chemotherapy is not very effective in most Nf2-negative schwannomas, surgical removal or radiation therapy is required. However, depending on the size and site of the tumor, these approaches may cause loss of auditory or vestibular functions, and severely decrease the post-surgical wellbeing. Here, we examined the feasibility of cold atmospheric pressure plasma (CAP) as an intra-operative adjuvant treatment for VS after surgery. Cell death was efficiently induced in both human HEI-193 and mouse SC4 VS cell lines upon exposure to CAP for seven minutes. Interestingly, both apoptosis and necroptosis were simultaneously induced by CAP treatment, and cell death was not completely inhibited by pan-caspase and receptor-interacting serine/threonine-protein kinase 1 (RIK1) inhibitors. Upon CAP exposure, cell death phenotype was similarly observed in patient-derived primary VS cells and tumor mass. In addition, CAP exposure after the surgical removal of primary tumor efficiently inhibited tumor recurrence in SC4-grafted mouse models. Collectively, these results strongly suggest that CAP should be developed as an efficient adjuvant treatment for VS after surgery to eliminate the possible remnant tumor cells, and to minimize the surgical area in the brain for post-surgical wellbeing.

Should primary tumor be resected for non-small cell lung cancer with malignant pleural disease unexpectedly found during operation?-a systemic review and meta-analysis.

Non-small cell lung cancer (NSCLC) with malignant pleural disease (MPD) was considered to be contraindication for surgery, but sometimes MPD was unexpectedly found intraoperatively. There was no consensus on the role of surgical intervention on the primary tumor in patients with MPD. The object of this research was to assess whether exairesis of primary tumor could prolong survival time. A systemic research of literature was performed on the databases of PubMed, Embase and Web of Science. Literatures examining surgical benefit or other prognostic factors among NSCLC patients with MPD unexpectedly found during operations were included. Hazard ratio (HR) with 95% confidence interval (95% CI) as well as P value is applied for prognostic role of surgical removal or other potential factors. Nine articles with a total number of 861 patients fulfilled the eligibility criteria, five of them compared the survival benefit between exploration and resection among NSCLC patients with unexpected MPD, and other studies also investigated the prognostic factors in these patients. There was a significant survival benefit in patients with primary tumor resection (HR =0.443; 95% CI: 0.344-0.571; P<0.001). This role was further detected when stratified by analysis method and ethnicity. Female was an independent favorable predicted factor (HR =0.788; 95% CI: 0.648-0.959; P=0.017) while higher N-stage was a risk factor (HR =1.879; 95% CI: 1.307-2.701; P=0.001). Among patients who received primary tumor resection, higher N-stage was also a risk factor for poorer survival (HR =2.021; 95% CI: 1.496-2.730; P<0.001). Resection of primary tumor, female and lower-N stage were suggested to be beneficial prognostic factor among NSCLC patients who were detected with MPD for the first time in the operating room. And among these people who received surgical removal of primary tumor, lower N-stage also indicated a better survival.

Abstract 3996: KA2237 and KA2507: Novel, oral cancer immunotherapeutics targeting PI3K-p110β/p110δ and HDAC6 with single-agent and combination activity

Abstract Two de novo-designed classes of orally-active immunotherapeutics - selectively targeting the PI3K-p110β/p110δ and HDAC6 enzymes - for solid and hematological cancer treatment will be described. The former, exemplified by the clinical candidate KA2237, are uniquely-selective inhibitors of the PI3K-p110β/p110δ isoforms, displaying immunotherapeutic activity and inhibiting primary tumor growth and metastasis. The latter, for which KA2507 is the candidate compound, are HDAC6-specific inhibitors, which inhibit tumor growth through regulation of aggresome formation, and inhibition of PD-L1 expression via decrease of STAT3 phosphorylation. In both cases, selectivity has been achieved over other enzyme superfamily members, with the aim being to minimize mechanism-related toxicity, thereby potentially providing opportunities to enable elevated single dose levels - and broad combination modalities not possible with pan-inhibitors of both enzymes - to be investigated. The PI3K-p110β/p110δ and HDAC6 inhibitors display potent oral activity as single agents in in vivo tumor syngeneic models, impacting on growth inhibition, PD and tumor marker responses; the PI3K-p110β/p110δ inhibitors also inhibit metastatic spread and, following surgical removal of primary tumor, confer promising inhibition of tumor regrowth. Crucially, the inhibitors work in combination with one another, making this co-therapy approach unique in oncology, and potentially important clinically in overcoming resistance mechanisms in both solid and hematological cancer. The rationale for this combination is based upon immunotherapeutic and cell signalling mechanisms, which will be described. KA2237 is entering Phase I studies in patients with lymphoma as a single agent in Q1 2016, with KA2507 scheduled to follow in Q3 to treat multiple myeloma. Further clinical investigations into solid tumor immunotherapy - both single agent- and combination-studies - are planned. Citation Format: Stephen J. Shuttleworth. KA2237 and KA2507: Novel, oral cancer immunotherapeutics targeting PI3K-p110β/p110δ and HDAC6 with single-agent and combination activity. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3996.

Abstract 3251: A Senescence-like phenotype associates with rapid metastasis promotion following antiangiogenic drug resistance and therapy withdrawal

Abstract Few studies have investigated mechanisms of antiangiogenic drug resistance in mouse models that faithfully recapitulate clinically relevant spontaneous metastatic disease or evaluate the impact of therapy cessation on tumor and stromal cell growth. Generation of such models may be critical to study reported instances of antiangiogenic therapy-induced metastasis in animals that have often proved challenging to confirm in patients. Here we describe the derivation of several human and mouse tumor cell lines obtained from spontaneous metastatic lesions present after surgical removal of primary tumors and following long-term in vivo treatment with sunitinib or axitinib. Selected drug-resistant metastatic (kidney, breast, and melanoma) and non-malignant stromal cell variants (endothelial and fibroblast) were continuously exposed to drug in vitro and then evaluated following both short- and long-term treatment removal (48 hours and 6 months, respectively). Our results show that metastatic drug-resistant cells receiving sustained treatment were re-sensitized to therapy upon orthotopic re-implantation into treatment-naïve animals, suggesting a predominant host-mediated role in therapy failure. However, significant increases in tumor growth and metastatic potential were observed in all models when cells were re-implanted and therapy stopped, suggesting a tumor-dependent pro-metastatic mechanism activated by therapy withdrawal. Whole genome expression analysis for resistant cells on and off treatment revealed reversible and irreversible gene changes implicating a senescence-like phenotype capable of influencing metastatic potential. Senescent-like characteristics included increased cell size, decreased proliferation, cell cycle check-point protein alteration, and therapy-induced SA-β-galactosidase expression, depending on the cell line. Critically, antiangiogenic therapy could induce a senescence associated secretory phenotype (SASP) in both tumor and stroma cells which reversed or persisted following therapy cessation in certain instances. Importantly, we found that interleukin-6 (IL-6) - a major component of the SASP - was upregulated in resistant tumor and stroma cells, but only remained upregulated in stromal cells following therapy withdrawal. These results suggest that antiangiogenic treatment-induced senescence-like changes may contribute to treatment failure and contribute to pro-metastatic growth depending on cell origin (i.e., tumor or stroma) and whether treatment is sustained or stopped. Citation Format: Michalis Mastri, Amanda Tracz, Biao Liu, Christina R. Lee, John ML Ebos. A Senescence-like phenotype associates with rapid metastasis promotion following antiangiogenic drug resistance and therapy withdrawal. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3251.

The effect of the gastrectomy on survival in patients with metastatic gastric cancer: a study of ASMO.

To investigate the role of surgical resection of primary tumor on overall survival (OS) in advanced gastric cancer patients at the time of diagnosis. The survival rates of metastatic gastric cancer patients whose gastric primary tumor was resected at time of diagnosis were compared with metastatic gastric cancer patients whose primary tumor was nonresected. The median progression-free survival and OS in operated and nonoperated group were 10 versus 6, 14 versus 9 months, respectively (p < 0.001). In multivariate analysis, gastric resection of primary tumor, Eastern Cooperative Oncology Group performance status, second-line chemotherapy had a significant effect on OS (hazard ratio [HR]: 0.52 [95% CI: 0.38-0.71], HR: 0.57 [95% CI: 0.42-0.78], HR: 1.48 [1.09-2.01]; p ≤ 0.001, p = 0.001 and p = 0.012, respectively). Subpopulations of patients with metastatic gastric cancer might benefit from surgical removal of primary tumor.

Surgical removal of primary tumor in metastatic breast cancer: Impact on health-related quality of life (HR-QOL) in a randomized controlled trial (RCT).

1124 Background: We have previously reported in a RCT that surgical removal of the primary tumor (versus not) did not significantly improve median overall survival (18.8 Vs 20.5 months) in women wi...

Abstract P5-04-05: Preclinical modeling of luminal breast cancer: Recapitulating progression to lethal and tamoxifen-resistant lung metastases in novel patient-derived xenotransplant models in prolactin-humanized mice

Abstract Seventy to eighty percent of newly diagnosed breast cancer cases are estrogen receptor(ER)-positive and are classified as luminal. Despite hormone therapy, 25-30% of luminal breast cancers will recur within 15 years of surgical removal of the primary tumor, and many of these patients will die from currently incurable distant metastases. Lung and bone are the most common organ sites for distant breast cancer metastases, with either site affected in approximately 70% of patients based on autopsy studies. A major hurdle for therapeutic progress with luminal breast cancer is the historical difficulty to establish xenograft models of human luminal breast cancer in mice. In particular, there is a need for experimental ER-positive breast cancer models that recapitulate distant metastasis formation from orthotopic tumor implants in mammary glands. Such experimental models will allow surgical resection of the primary tumor followed by clinically relevant testing of targeted adjuvant agents against distant residual disease. We have engineered prolactin-humanized mice that have been backcrossed for ten generations into the Nod-SCOD-IL2Rgamma (NSG) immunodeficient background. These prolactin-humanized mice display improved take rates of patient-derived luminal breast cancer. Using prolactin-humanized mice we have established patient-derived serially transplantable luminal breast cancer models that metastasize to distant sites when grown as primary tumors in the mammary gland. One of the ER-positive lines, PDX2, effectively metastasizes to lungs in 100% of animals within 55 days of grafting into mammary glands. PDX2 lung metastases retain ER and progesterone receptor (PR) expression as well as expression of the luminal marker, GATA3, and display high degree of Ki67 positivity indicating rapidly proliferative lesions. Importantly, metastatic PDX2 lesions show only limited dormancy. In fact, when primary PDX2 tumors are surgically removed at Day 55, mice will die from lung metastases around Day 150. Estrogen supplementation is required for establishment of PDX2 tumors in mice. After primary PDX2 tumors are established in mammary glands in the presence of estradiol, primary tumors respond to tamoxifen with growth suppression but do not undergo tumor regression, and develop resistance to tamoxifen. Treatment of mice with adjuvant tamoxifen following surgical removal of primary PDX2 tumors led to extensive regression of existing lung metastases to barely detectable levels within 30 days of surgery. However, tamoxifen-refractory PDX2 lung metastases regrew during the next 30 day-period in the continued exposure to tamoxifen. Molecular phenotyping of the PDX2 model and other new luminal breast cancer models are ongoing, with the goal of characterizing tamoxifen-responsive and tamoxifen-refractory primary and metastatic lesions. Long-term, our intent is to use the PDX2 and other preclinical xenograft models in prolactin-humanized mice to systematically explore agents for synergy with anti-estrogens to establish curative combination treatments for metastatic luminal breast cancer. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-04-05.

Abstract S2-02: Surgical removal of primary tumor and axillary lymph nodes in women with metastatic breast cancer at first presentation: A randomized controlled trial

Abstract BACKGROUND: The role of loco-regional treatment, in women with metastatic breast cancer (MBC) at first presentation, is debatable. Preclinical evidence suggests that such treatment may facilitate growth of metastatic disease. On the other hand, many retrospective analyses in clinical cohorts have suggested favorable impact of loco-regional treatment in these patients. However, these results are likely to be influenced by selection bias. We conducted a prospective randomized controlled trial to assess the impact of loco-regional treatment on outcome in women with metastatic breast cancer at initial diagnosis. [NCT00193778] METHODS: Women with metastatic breast cancer at initial diagnosis and planned to be treated with anthracycline based chemotherapy (CT) were registered for the study. Those who had objective tumor response after 6 cycles of CT were randomized to one of the following arms: ‘LRT’ (loco-regional treatment) or ‘No-LRT’ (no loco-regional treatment). Patients were stratified by endocrine receptor (ER) status, site of metastases (visceral Vs bone Vs both) and number of metastatic lesions (&amp;lt; 3 Vs &amp;gt; 3). Women in LRT arm received surgery (breast conservation or mastectomy plus axillary lymph node dissection) followed by radiation therapy (RT), as per standard adjuvant guidelines. Women in No-LRT arm were followed up without surgery and RT. Both groups received standard endocrine therapy after last cycle of chemotherapy, if indicated. They were regularly followed up with clinical evaluation. Appropriate imaging was performed within 6 months after randomization and thereafter as clinically indicated. The primary endpoint was overall survival (OS). RESULTS: Between Feb 2005 and Jan 2013, 350 women were randomized, 173 in LRT and 177 in No-LRT arm. The data cutoff was in May 2013. The two arms were balanced with respect to age, clinical tumor size, HER2 receptor status and stratification factors. Eight (5.8%) patients in the LRT arm did not undergo loco-regional therapy while 19 (10.7%) patients in the No-LRT arm underwent surgical removal of primary tumor because of palliative reasons. The median follow-up was 17 months and 218 deaths (LRT = 111/173, No-LRT = 107/177) had been recorded at data cutoff. The median OS in LRT and No-LRT arms were 18.8 and 20.5 months (HR = 1.07, 95%CI = 0.82-1.40, p = 0.60) and the corresponding 2-year OS were 40.8% and 43.3%, respectively. After adjusting for age, ER status, HER2 receptor status, site of metastases and number of metastatic lesions in a Cox regression model, there was no significant difference in OS between LRT and No-LRT arms (HR = 1.00, 95%CI = 0.76-1.33, p = 0.98). There was no interaction between the effect of LRT and covariates in the model. CONCLUSIONS: Loco-regional treatment of the primary tumor and axillary nodes has no impact on OS in patients diagnosed with MBC at initial presentation, who have responded to frontline chemotherapy. We were unable to identify any subgroups that are likely to benefit from LRT. Such treatment should be reserved for women who need it for palliative reasons. Detailed analysis will be presented at the Symposium. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr S2-02.