Lower-intensity CPX-351 + venetoclax for patients with newly diagnosed AML who are unfit for intensive chemotherapy

7031

Background: CPX-351 (US: Vyxeos; Europe: Vyxeos liposomal) is a dual-drug liposomal encapsulation of daunorubicin and cytarabine in a synergistic 1:5 molar ratio. CPX-351 is approved for newly diagnosed, therapy-related AML or AML with myelodysplasia-related changes in patients (pts) who are candidates for intensive chemotherapy (IC) and aged ≥1 year in the US and adults in Europe. However, the appropriate dosage of CPX-351 in pts unfit for IC may be different from the label dosage. Venetoclax (VEN; BCL-2 inhibitor) + low-dose cytarabine has demonstrated efficacy in unfit pts with AML, and drug synergism/additivity in preclinical studies provided a rationale for combining CPX-351 + VEN clinically. Our study evaluates the safety and efficacy of lower-intensity CPX-351 + VEN in adults with newly diagnosed AML who are unfit for IC. Methods: This is an ongoing, open-label, phase 1b study (NCT04038437). Pts who achieve at least partial remission after 1 or 2 cycles may receive up to 4 similar cycles in the dose-exploration phase (DEP) or up to 8 similar cycles in the expansion phase (EP). Pts are assessed for response (morphology, measurable residual disease [MRD]) and monitored for safety and survival. Results: The data include 31 pts enrolled by 9/15/2021, with a data cutoff of 12/2/2021: 4 pts in DEP at dose level 1 (CPX-351 20 units/m2 on Days 1 and 3 + VEN 400 mg on Days 2 to 21 of each cycle), 7 pts in DEP at dose level 2 (CPX-351 40 units/m2 + VEN 400 mg), and a total of 20 pts in DEP and EP at dose level 1b (CPX-351 30 units/m2 + VEN 400 mg; established as the recommended phase 2 dose). Pts were unfit for IC based on age ≥75 y (n = 15) or health (ECOG PS of 2 to 3 and/or comorbidities [n = 16]). Median age was 74 y (range: 60, 90); 65% were male; 77% had de novo AML; 58% had poor-risk disease; and 23% had a TP53 mutation. Nonhematologic treatment-emergent adverse events (TEAEs) in ≥20% of pts were diarrhea (26%), cough (23%), dyspnea (23%), and nausea (23%). Hematologic grade ≥3 TEAEs were reported in 17 (55%) pts; no nonhematologic grade ≥3 TEAE was reported in > 10% of pts. There were no deaths by Day 30; mortality at Day 60 was 13%, with deaths due to myocardial infarction unrelated to therapy (n = 1), worsening lung infection (n = 1), and disease progression (n = 2). Median (IQR) recovery times were 30 d (22, 34.5) to neutrophils ≥500/μL and 21 d (21, 27) to platelets ≥50,000/μL. Complete remission (CR) or CR with incomplete neutrophil or platelet recovery (CRi) was achieved by 16/28 (57%) evaluable pts. All 16 of these pts achieved remission (CR or CRi) after the first cycle. MRD negativity was achieved by 12/16 (75%) pts with CR or CRi, primarily after Cycle 1 (Cycle 1: n = 8; Cycle 2: n = 2; Cycle 3: n = 1; Cycle 4: n = 1). Survival data are not yet mature. Conclusions: Lower-intensity CPX-351 + VEN was generally well tolerated in adults with newly diagnosed AML who are unfit for IC and showed promising initial efficacy, with CR or CRi in the majority of pts. Clinical trial information: NCT04038437.

V-FAST master trial: Preliminary results of treatment with CPX-351 plus midostaurin in adults with newly diagnosed FLT3-mutated acute myeloid leukemia

7043

Background: CPX-351 (US: Vyxeos; Europe: Vyxeos liposomal), a dual-drug liposomal encapsulation of daunorubicin and cytarabine in a synergistic 1:5 molar ratio, is approved for newly diagnosed, therapy-related AML or AML with myelodysplasia-related changes in patients aged ≥1 year in the US and in adults in Europe. In a phase 3 study in older adults with newly diagnosed, high-risk/secondary AML, CPX-351 significantly improved overall survival and remission rates versus conventional 7+3, with a comparable safety profile. Preclinical data suggest CPX-351 may have synergistic activity with targeted agents, including the FLT3 inhibitor midostaurin (MID). Herein, we report preliminary results for the cohort of adults treated with CPX-351 + MID in the V-FAST (Vyxeos – First Phase Assessment with Targeted Agents) trial. Methods: V-FAST is an open-label, multicenter, multiarm, nonrandomized, phase 1b master trial (NCT04075747) to evaluate the safety and preliminary efficacy of CPX-351 combined with targeted agents (midostaurin, venetoclax, enasidenib). Eligible adults in the CPX-351 + MID cohort were aged 18 to 75 years, had newly diagnosed AML with a FLT3 internal tandem duplication (ITD) or tyrosine kinase domain (TKD) mutation, were fit for intensive chemotherapy, and had an ECOG performance status of 0 to 2. The dose-exploration phase (3+3 design) determined a recommended phase 2 dose of CPX-351 100 units/m2 (daunorubicin 44 mg/m2 + cytarabine 100 mg/m2) on Days 1, 3, and 5 + MID 50 mg BID on Days 8 to 21. There were no dose-limiting toxicities, and additional patients were enrolled in the expansion phase at this dose. Results: A total of 23 patients received CPX-351 + MID and had sufficient data to be included in the analysis (cutoff date: 1/20/2022). Patient baseline characteristics are shown in the Table. Treatment-emergent adverse events (TEAEs) in ≥40% of patients included febrile neutropenia (78%), nausea (65%), increased alanine aminotransferase (57%), leukopenia (57%), thrombocytopenia (57%), headache (43%), and hyponatremia (43%). All patients experienced a grade 3/4 TEAE, primarily hematologic events. Nonhematologic grade 3/4 TEAEs in ≥2 patients included pneumonia (17%), lung infection (13%), and hyperglycemia (9%). There were no grade 5 TEAEs and no deaths on or before Day 60. Complete remission was achieved by 18/22 (82%) evaluable patients after the first induction cycle. Conclusions: Preliminary results from the V-FAST trial suggest CPX-351 + MID is feasible, with a manageable safety profile and promising remission rates in adults with newly diagnosed AML who have a FLT3 mutation. Clinical trial information: NCT04075747. [Table: see text]

Preliminary results of V-FAST, a phase 1b master trial to investigate CPX-351 combined with targeted agents in newly diagnosed AML

7026

Background: CPX-351 (US: Vyxeos; EU: Vyxeos Liposomal), a dual-drug liposomal encapsulation of daunorubicin and cytarabine in a synergistic 1:5 molar drug ratio, is approved by the US FDA and EMA for adults with newly diagnosed t-AML or AML with myelodysplasia-related changes. Preclinical data suggest CPX-351 may exert synergistic activity when combined with agents such as the BCL-2 inhibitor venetoclax (VEN) or FLT3 inhibitor midostaurin (MIDO). Methods: V-FAST (Vyxeos – First Phase Assessment With Targeted Agents) is an open-label, multicenter, phase 1b master trial (NCT04075747) to evaluate safety and establish the recommended phase 2 dose (RP2D) of CPX-351 combined with targeted agents in patients (pts) aged 18-75 y with untreated AML who are fit for intensive chemotherapy. The study includes a dose-exploration phase (3+3 design) and subsequent expansion phase. Pts received CPX-351 (dose level 1 for first induction [DL1]: 100 units/m2 on Days 1, 3, and 5) plus VEN (Arm A; DL1: 400 mg on Days 1-14), MIDO (Arm B; DL1: 50 mg BID on Days 8-21), or the IDH2 inhibitor enasidenib ([ENA] Arm C; DL1: 100 mg on Days 8-28) based on mutation testing. Results: Among 21 pts with available data enrolled by 11/06/20 (24 pts enrolled total; data cut-off: 01/19/21), the median age was 54 y (range: 35, 69). In Arm A (n = 17), 11 (65%) pts had de novo AML, 5 (29%) had an antecedent hematologic disorder (2 [12%] had myelofibrosis), and 2 (12%) had t-AML; 12 (71%) had adverse-risk AML; and 6 (35%) had mutated TP53. In Arms B (n = 3) and C (n = 1), all pts had intermediate-risk de novo AML. DL1 was the RP2D in Arms A and B; the RP2D in Arm C is still under investigation. In Arm A, 1/6 pts in the dose-exploration phase had 2 dose-limiting toxicities (DLTs) of grade 4 neutropenia and thrombocytopenia that extended beyond 49 days; no DLTs have occurred for Arms B and C. The combinations exhibited manageable safety profiles (Table). Of pts with available response data, complete remission (CR) or CR with incomplete platelet or neutrophil recovery was achieved by 6/14 (43%) pts in Arm A, including 4 (29%) with CR. All pts in Arms B and C achieved CR. Conclusions: These preliminary results suggest CPX-351 can be combined with VEN and MIDO with manageable toxicities in newly diagnosed AML pts, with DL1 determined to be the RP2D. The study is ongoing and actively enrolling pts; updated results will be presented at the meeting. Clinical trial information: NCT04075747. [Table: see text]

Evidence for 2-Methoxyestradiol-Mediated Inhibition of Receptor Tyrosine Kinase RON in the Management of Prostate Cancer

2-Methoxyestradiol (2-ME₂) possesses anti-tumorigenic activities in multiple tumor models with acceptable tolerability profile in humans. Incomplete understanding of the mechanism has hindered its development as an anti-tumorigenic compound. We have identified for the first-time macrophage stimulatory protein 1 receptor (MST1R) as a potential target of 2-ME₂ in prostate cancer cells. Human tissue validation studies show that MST1R (a.k.a RON) protein levels are significantly elevated in prostate cancer tissues compared to adjacent normal/benign glands. Serum levels of macrophage stimulatory protein (MSP), a ligand for RON, is not only associated with the risk of disease recurrence, but also significantly elevated in samples from African American patients. 2-ME₂ treatment inhibited mechanical properties such as adhesion and elasticity that are associated with epithelial mesenchymal transition by downregulating mRNA expression and protein levels of MST1R in prostate cancer cell lines. Intervention with 2-ME₂ significantly reduced tumor burden in mice. Notably, global metabolomic profiling studies identified significantly higher circulating levels of bile acids in castrated animals that were decreased with 2-ME₂ intervention. In summary, findings presented in this manuscript identified MSP as a potential marker for predicting biochemical recurrence and suggest repurposing 2-ME₂ to target RON signaling may be a potential therapeutic modality for prostate cancer.

Palmatine suppresses glutamine-mediated interaction between pancreatic cancer and stellate cells through simultaneous inhibition of survivin and COL1A1

Reciprocal interaction between pancreatic stellate cells (PSCs) and cancer cells (PCCs) in the tumor microenvironment (TME) promotes tumor cell survival and progression to lethal, therapeutically resistant pancreatic cancer. The goal of this study was to test the ability of Palmatine (PMT) to disrupt this reciprocal interaction in vitro and examine the underlying mechanism of interaction. We show that PSCs secrete glutamine into the extracellular environment under nutrient deprivation. PMT suppresses glutamine-mediated changes in GLI signaling in PCCs resulting in the inhibition of growth and migration while inducing apoptosis by inhibition of survivin. PMT-mediated inhibition of (glioma-associated oncogene 1) GLI activity in stellate cells leads to suppression (collagen type 1 alpha 1) COL1A1 activation. Remarkably, PMT potentiated gemcitabine’s growth inhibitory activity in PSCs, PCCs and inherently gemcitabine-resistant pancreatic cancer cells. This is the first study that shows the ability of PMT to inhibit growth of PSCs and PCCs either alone or in combination with gemcitabine. These studies warrant additional investigations using preclinical models to develop PMT as an agent for clinical management of pancreatic cancer.

Pancreatic cancer: Current status and Challenges

Purpose of the review

The 5-year survival rate of patients with pancreatic cancer (PanCA) has remained stagnant. Unfortunately, the incidence is almost equal to mortality rates. These facts underscore the importance of concerted efforts to understand the pathology of this disease. Deregulation of multiple signaling pathways involved in a wide variety of cellular processes including proliferation, apoptosis, invasion, and metastasis contribute not only to cancer development but also to therapeutic resistance. The purpose of this review is to summarize current understanding of etiological factors including emerging evidence on the role of infectious agents, factors associated with therapeutic resistance and therapeutic options.

Recent findings

The unique aspect of PanCA is "desmoplasia", a process that involves proliferation of stromal fibroblasts and collagen deposition in and around the filtrating cancer. Recent studies have identified pancreatic stellate cells (PSCs) as a potential source of such desmoplasia. Biphasic interactions between PSCs and cancer cells, endothelial cells, and/or myeloid derived suppressor cells in the tumor microenvironment contribute to pancreatic carcinogenesis.

Summary

We summarize limitations of current therapeutic approaches and potential strategies to overcome these limitations using natural products including botanicals as adjuvant/neo-adjuvant for effective management of PanCA.

Abstract 5268: Nexrutine and palmatine mediated effects on the STAT3/EP4/IL-6 axis in pancreatic cancer

With a 5 year survival of less than 8%, the poor prognosis of pancreatic cancer (PanCA) underlines the importance of improving therapies for effective management of this disease. In previous studies, we identified the tumor cell growth inhibitory activities for Nexrutine® (Nx, a bark extract from Phellodendron amurense) and palmatine (PMT) which is a constituent of Nx. These studies revealed an important role for downregulation of KRAS downstream effectors including GLI, STAT3 and NF-κB in mediating growth inhibitory effects. Remarkably, both Nx and PMT exerted synergistic growth inhibitory effects in combination with the conventional chemotherapeutic agent, Gemcitabine (GEM). Despite such promising in vitro observations, the in vivo efficacy of Nx or PMT had not been established. In this investigation, we evaluated the ability of Nx and PMT to (i) prevent the development of pancreatic tumors; and (ii) inhibit the growth of patient derived pancreatic cancer tissue in short term ex vivo cultures. Studies were also conducted to investigate the underlying molecular mechanism using cell culture models. Our results show that both Nx and PMT are well tolerated in vivo as evidenced by a lack of significant changes in the body weights of athymic mice implanted with Capan-2 cells. Interestingly, both Nx and PMT showed a significant decrease in the circulating levels of inflammatory molecules including IL-6 and CXCL1. In this first proof-of-concept study, PMT treated animals demonstrated a trend towards decreased pancreatic tumor weight with associated histopathogical changes. Remarkably, both Nx and PMT inhibited the growth of patient derived pancreatic cancer cells. Mechanistic investigations identified downregulation of STAT3, TrkA, Src, and RPS6 activities as potential contributors to Nx or PMT-induced synergistic growth inhibitory effects with GEM. Further investigation of STAT3 signaling revealed the involvement of the prostaglandin receptor, EP4, in a potential feedback loop with STAT3 and in asserting STAT3-mediated inhibition of autophagy. Taken together these data support potential utility for Nx and/or PMT in the management of PanCA and suggest that these agents use multiple mechanisms to affect growth of pancreatic tumors. Supported by NCCIH (R01 AT007448; APK) and VA-MERIT Award (I01 BX 000766; APK).

Citation Format: Amanda R. Munoz, Roble G. Bedolla, Paul Rivas, Divya Chakravarthy, Robert L. Reddick, Martha A. Hanes, Glenn A. Halff, Rita Ghosh, Addanki P. Kumar. Nexrutine and palmatine mediated effects on the STAT3/EP4/IL-6 axis in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5268. doi:10.1158/1538-7445.AM2017-5268

Preparation of a Dextran-Based Degradable Absorbent Suitable for Wound Healing Applications

Hydrolytically degradable microspheres were prepared by crosslinkng dextran under alkaline conditions with cyanogen bromide (CNBr). The crosslinking was performed in a water-in-oil type heterophase suspension medium. Dextran Mws of 500,000 and 40,000 were used for the preparations, CNBr:dextran-OH mole ratios ranged from 0.021:1 to 0.21:1. The microspheres absorbed significant quantities of water (20-45 times their own weight), and were shown to degrade in neutral buffer to soluble and non-toxic products. Hydration and degradation behavior varied linearly with the ratios of CNBr to dextran. The physical properties were dependent on the molecular weights of the dextrans used in the preparations. In contrast to epichlorohydrin crosslinked dextran microspheres that are resistant to hydrolysis and only degrade enzymatically, the described microspheres degrade more rapidly by simple hydrolysis of the iminocarbonate bonds that constitute the microspheres. Such degradative properties are ideal in the application of the microspheres as wound filers and as components of wound dressings.

Combined targeting of STAT3/NF-κB/COX-2/EP4 for effective management of pancreatic cancer

PURPOSE

Near equal rates of incidence and mortality emphasize the need for novel targeted approaches for better management of patients with pancreatic cancer. Inflammatory molecules NF-κB and STAT3 are overexpressed in pancreatic tumors. Inhibition of one protein allows cancer cells to survive using the other. The goal of this study is to determine whether targeting STAT3/NF-κB crosstalk with a natural product Nexrutine can inhibit inflammatory signaling in pancreatic cancer.

EXPERIMENTAL DESIGN

HPNE, HPNE-Ras, BxPC3, Capan-2, MIA PaCa-2, and AsPC-1 cells were tested for growth, apoptosis, cyclooxygenase-2 (COX-2), NF-κB, and STAT3 level in response to Nexrutine treatment. Transient expression, gel shift, chromatin immunoprecipitation assay was used to examine transcriptional regulation of COX-2. STAT3 knockdown was used to decipher STAT3/NF-κB crosstalk. Histopathologic and immunoblotting evaluation was performed on BK5-COX-2 transgenic mice treated with Nexrutine. In vivo expression of prostaglandin receptor E-prostanoid 4 (EP4) was analyzed in a retrospective cohort of pancreatic tumors using a tissue microarray.

RESULTS

Nexrutine treatment inhibited growth of pancreatic cancer cells through induction of apoptosis. Reduced levels and activity of STAT3, NF-κB, and their crosstalk led to transcriptional suppression of COX-2 and subsequent decreased levels of prostaglandin E2 (PGE2) and PGF2. STAT3 knockdown studies suggest STAT3 as negative regulator of NF-κB activation. Nexrutine intervention reduced the levels of NF-κB, STAT3, and fibrosis in vivo. Expression of prostaglandin receptor EP4 that is known to play a role in fibrosis was significantly elevated in human pancreatic tumors.

CONCLUSIONS

Dual inhibition of STAT3-NF-κB by Nexrutine may overcome problems associated with inhibition of either pathway.

Abstract LB-101: Targeting pancreatic cancer stroma with Palmatine, a novel compound from herbal supplement

Pancreatic ductal adenocarcinoma is the fourth leading cause of cancer related deaths with 5-year survival rates less than 6%. Survival periods with gemcitabine in combination with various agents average over 6 months. Desmoplasia is a striking feature of pancreatic cancer. It is characterized by formation of dense stroma surrounding the tumor. This dense stroma serves as a therapeutic barrier for many chemotherapeutic drugs, in turn decreasing their efficacy. Pancreatic stellate cells (PSCs) have been reported to be involved in the observed desmoplastic reaction. Therefore targeting this stroma can be an alternate approach to pancreatic cancer. Previous studies from our laboratory showed that Nexrutine, a herbal supplement inhibits proliferation of multiple pancreatic cancer cells through modulation of Stat3/NFκB/Cox-2 signaling and reduced the number of animals developing fibrosis in vivo. To the best of our knowledge, the effect of Nexrutine or its active components on pancreatic stroma has not been studied. In this study we evaluated the effect of Nexrutine and Palmatine, an active component of Nexrutine, for its ability to target the stroma. Our studies show for the first time that Palmatine (i) inhibits proliferation of PSCs as well as the tumor cells; (ii) inhibits hedgehog signaling as evidenced by GLI expression and reporter activity; (iii) modulates expression and activity of downstream targets of GLI including Patched1, IKKB-ε and anti-apoptotic protein Survivin. Remarkably Palmatine treatment inhibits invasive ability of PSCs that is associated with reduced levels of COL1A1. Overall this is the first study reporting the ability of Palmatine to modulate Hh signaling and may have utility either alone or in conjunction with Gemcitabine for treatment of pancreatic ductal adenocarcinoma. Supported by NCCAM (AT 005513-01A1 and AT 007448l; APK).

Citation Format: Divya Chakravarthy, Jingjing Gong, Rosa F. Hwang, Addanki Pratap Kumar. Targeting pancreatic cancer stroma with Palmatine, a novel compound from herbal supplement. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-101. doi:10.1158/1538-7445.AM2013-LB-101

Abstract 5392: Metabolic profiling of castrate-resistant prostate cancer reveals novel role for bile acids in driving castration resistance

The 5-year survival for metastatic castrate-resistant prostate cancer patients is less than 30% despite significant progress in the understanding of prostate cancer biology and development of novel therapeutic agents. A major contributing factor for the observed low survival rate of patients with castrate resistant disease is the lack of knowledge regarding metabolic alterations and their underlying contributions during development of castrate-resistant phenotype. Studies conducted in our laboratory and others identified a potential role for 2-methoxyestradiol (2-ME2) to prevent prostate cancer development and progression through inhibition of the anti-apoptotic protein FLIP. The goal of the current study was to identify biochemical changes in response to castration and treatment with 2-ME2 in serum from transgenic adenocarcinoma of mouse prostate (TRAMP) mice using mass spectrometry based global profiling. We identified a total of 54 biochemicals of which 16 increased and 38 decreased in castrated animals compared to sham-castration. Treatment of sham-castrated animals with low and high doses of 2-ME2 altered 91 and 145 biochemicals respectively. On the other hand treatment of castrated animals modulated 89 and 106 biochemicals. Cumulative analysis of these data also identified alteration of 60 biochemicals associated with castration effect, 149 with treatment and 70 interactions between castration and treatment effects. Castration affected metabolites involved in variety of metabolic pathways including lipid, oxidative stress, energetics and bile acid. Given the data showing enhanced expression of FLIP in castrate-resistant prostate tumors and upregulation of bile acids in patients undergoing androgen deprivation therapy, we examined the activation of FLIP in prostate cancer cells in response to deoxycholic acid (DCA). Our data suggests that transcriptional activity of FLIP was higher in PC-3 cells treated with DCA. To the best of our knowledge, this is the first report demonstrating global metabolomic profiling of serum in response to castration and provide a framework for therapeutic targeting of bile acid metabolism. Supported by NIH CA 135451 (APK).

Citation Format: Divya Chakravarthy, Paul Rivas, Brian Keppler, Jianhua Ruan, Rita Ghosh, Addanki Pratap Kumar. Metabolic profiling of castrate-resistant prostate cancer reveals novel role for bile acids in driving castration resistance. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5392. doi:10.1158/1538-7445.AM2013-5392

Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.

A novel approach for detection and classification of mammographic microcalcifications using wavelet analysis and extreme learning machine

The objective of this paper is to reveal the effectiveness of wavelet based tissue texture analysis for microcalcification detection in digitized mammograms using Extreme Learning Machine (ELM). Microcalcifications are tiny deposits of calcium in the breast tissue which are potential indicators for early detection of breast cancer. The dense nature of the breast tissue and the poor contrast of the mammogram image prohibit the effectiveness in identifying microcalcifications. Hence, a new approach to discriminate the microcalcifications from the normal tissue is done using wavelet features and is compared with different feature vectors extracted using Gray Level Spatial Dependence Matrix (GLSDM) and Gabor filter based techniques. A total of 120 Region of Interests (ROIs) extracted from 55 mammogram images of mini-Mias database, including normal and microcalcification images are used in the current research. The network is trained with the above mentioned features and the results denote that ELM produces relatively better classification accuracy (94%) with a significant reduction in training time than the other artificial neural networks like Bayesnet classifier, Naivebayes classifier, and Support Vector Machine. ELM also avoids problems like local minima, improper learning rate, and over fitting.

Expression and secretion of TGF-beta isoforms and expression of TGF-beta-receptors I, II and III in normal and neoplastic human breast

We investigated gene expression of the TGF-beta signalling system (including peptides and receptors) in normal and malignant breast tissue. Additionally, gene and protein expression was determined in a series of primary epithelial and stromal cultures derived from these tissues. TGF-beta isoforms and their receptors were expressed by both tissue sets, however the percentage of samples expressing each transcript varied. In normal breast, both TGF-beta1 and TGF-beta3 were found in most samples (88 and 89% respectively), with fewer expressing TGF-beta2 (68%). A similar pattern was evident in the tumours. Type I receptor of TGF-beta was constitutively expressed in normal breast and observed in most tumours (90%). Type II and III receptors of TGF-beta were expressed less frequently, although the type II receptor was mainly expressed by tumours (P=0. 0075). All primary cultures produced TGF-beta1 and TGF-beta2. Comparing respective cell populations, tumour stromal cells produced significantly more TGF-beta1 than those derived from normal breast (P<0.0001). Linear regression analysis showed stromal cultures derived from breast tumours exhibited a strong positive correlation (r=0.976) in the production of TGF-beta1 and TGF-beta2. Thus, TGF-beta and TGF-beta-receptors are widely and differentially expressed by normal and malignant breast and secretion of this peptide by epithelial and stromal cultures, in particular those derived from tumours, confirms its potential as an autocrine/paracrine regulator in breast cancer.

Nitric oxide-releasing polymers containing the [N(O)NO]- group

Ions of structure X[N(O)NO]- display broad-spectrum pharmacological activity that correlates with the rate and extent of their spontaneous, first-order decomposition to nitric oxide when dissolved. We report incorporation of this functional group into polymeric matrices that can be used for altering the time course of nitric oxide release and/or targeting it to tissues with which the polymers are in physical contact. Structural types prepared include those in which the [N(O)NO]- group is attached to heteroatoms in low molecular weight species that are noncovalently distributed throughout the polymeric matrix, in groupings pendant to the polymer backbone, and in the polymer backbone itself. They range in physical form from films that can be coated onto other surfaces to microspheres, gels, powders, and moldable resins. Chemiluminescence measurements confirm that polymers to which the [N(O)NO]- group is attached can serve as localized sources of nitric oxide, with one prototype providing sustained NO release for 5 weeks in pH 7.4 buffer at 37 degrees C. The latter composition, a cross-linked poly-(ethylenimine) that had been exposed to NO, inhibited the in vitro proliferation of rat aorta smooth muscle cells when added as a powder to the culture medium and showed potent antiplatelet activity when coated on a normally thrombogenic vascular graft situated in an arteriovenous shunt in a baboon's circulatory system. The results suggest that polymers containing the [N(O)NO]- functional group may hold considerable promise for a variety of biomedical applications in which local delivery of NO is desired.

Evaluation of three new hydrocolloid dressings: retention of dressing integrity and biodegradability of absorbent components attenuate inflammation

Residues from hydrocolloid dressings (HCDs) that originate from matrix disintegration and nonbiodegradability of the absorbent components, may cause deep-seated, unresolved inflammation in tissue that appears otherwise healed. The purpose of this study was to evaluate three new HCDs that were formulated with the goal of attenuating the inflammatory responses that may arise from HCD therapy. Two of the HCDs (A-106 and A-107) consisted of conventional absorbents dispersed in a new maceration-resistant adhesive matrix. The same matrix, mixed with potentially biodegradable dextran microspheres, formed the third dressing (Dextran Bead Dressing [DBD]). In this pilot scale study these novel dressings were evaluated on full-thickness dermal wounds on swine. Restore (Hollister) and DuoDERM CGF (Convatec) dressings were used as controls. Wound healing was evaluated histomorphometrically. Pertinent histologic parameters were ranked from wound tissue that was harvested 18 days after wounding. Grossly visible dressing disintegration ranged from minimal (DBD) to severe (Restore). Disintegration of other dressings was moderate. The percentage of tissue sections exhibiting giant cells reflected, in parallel, the observed extent of dressing disintegration. Thirty-eight percent of wounds dressed with DBD contained giant cells; 74 and 100% of wounds treated with DuoDERM CGF and Restore, respectively, contained giant cells. DBD-dressed wounds had relatively fewer chronic inflammatory cells than other dressings. These wounds were also characterized by a well-organized collagen matrix and complete reepithelialization. The extent of wound closures was similar for all dressing types except Restore. Closure of Restore-dressed wounds was delayed compared with closure with DBD and DuoDERM CGF on all days of evaluation except one. A-106 and A-107 were comparable to DuoDERM CGF in retention of dressing integrity and the elicited inflammatory tissue response. The DBD dressing appears to possess equivalent properties of typical HCDs while causing minimal tissue reactions.