The prognostic significance of sialyl-Tn antigen in women treated with adjuvant chemotherapy for breast cancer

Background and purpose. Sialyl-Tn(STn) represents an aberrantly glycosylated mucin epitope which is expressed in breast cancer and other adenocarcinomas and is an important target for the development of novel immunotherapeutic approaches. It is a marker of adverse prognosis in colon and ovarian cancer, but information about its prognostic impact in breast cancer is limited. The primary aim of the present study was to investigate the influence of STn expression on outcome of invasive breast cancer in 207 women who received anthracyline-containing adjuvant chemotherapy in a prospective clinical trial.^ Methods. Expression of STn was determined by an immunohistochemical procedure using the B72.3 monoclonal antibody. The extent of staining was determined by two observers using a 0 through 4 point scale, with 0 representing $<$5% of cells staining; 1: 5-25%; 2: 26-50%; 3: 51-75%; and 4: $>$75%. Intraobserver and interobserver agreement was.78-.92 (kappa). Kaplan-Meier and Cox proportional regression survival analyses were used to compare STn-negative and STn-positive patients.^ Results. Forty-eight (23%) of the 207 specimens demonstrated positive staining of STn. With a median follow-up of five years, STn-positivity was associated with a higher 5-year recurrence-free survival time than STn-negativity (67% vs. 80%, respectively; p = 0.03). STn expression was significantly associated with menopausal status (p = 0.04) but not other conventional prognostic markers. The risk of breast cancer recurrence and death was assessed by multivariate Cox regression analyses with adjustment for lymph node status, tumor size, menopausal status, hormone receptor status, nuclear grade, S-phase fraction and ploidy. In the final multivariate model for recurrence-free survival, the three factors that showed prognostic significance were: lymph node status (hazard ratio (HR) 3.04, 95% confidence interval (CI) 1.08-8.49), STn expression (HR 2.02, 95% CI 1.09-3.73), and tumor size (HR 1.96, 95% CI 1.05-3.64). STn was also associated with worse overall survival (HR 2.16, 95% CI 0.95-4.92) in multivariate analysis.^ Conclusion. STn antigen was shown to be a predictor of poor outcome in breast cancer. This tumor-associated antigen may be a valuable marker for identifying individuals at high risk of developing recurrent disease who may benefit from adjuvant therapy targeted at STn following definitive local therapy. Further study is needed to clarify the biologic and prognostic role of STn in breast cancer. ^

Adherence to adjuvant chemotherapy and post-treatment surveillance in a large community-based cohort of patients with colon cancer

The objective of this dissertation was to determine the initiation and completion rates of adjuvant chemotherapy, its toxicity and the compliance rates of post-treatment surveillance for elderly patients with colon cancer using the linked Surveillance, Epidemiology, and End Results – Medicare database.^ The first study assessed the initiation and completion rate of 5-fluorouracil-based adjuvant chemotherapy and its relationship with patient characteristics. Of the 12,265 patients diagnosed with stage III colon adenocarcinoma in 1991-2005, 64.4% received adjuvant chemotherapy within 3-months after tumor resection and 40% of them completed the treatment. Age, marital status, and comorbidity score were significant predictors for chemotherapy initiation and completion.^ The second study estimated the incidence rate of toxicity-related endpoints among stage III colon adenocarcinoma patients treated with chemotherapy in 1991-2005. Of the 12,099 patients, 63.9% underwent chemotherapy and had volume depletion disorder (3-month cumulative incidence rate [CIR]=9.1%), agranulocytosis (CIR=3.4%), diarrhea (CIR=2.4%), nausea and vomiting (CIR=2.3%). Cox regression analysis confirmed such association (HR=2.76; 95% CI=2.42-3.15). The risk of ischemic heart diseases was slightly associated with chemotherapy (HR=1.08), but significantly among patients aged <75 with no comorbidity (HR=1.70). ^ The third study determined the adherence rate of follow-up cares among patients diagnosed with stage I-III colon adenocarcinoma in 2000 - June 2002. We identified 7,348 patients with a median follow-up of 59 months. The adherence rate was 83.9% for office visits, 29.4% for CEA tests, and 74.3% for colonoscopy. Overall, 25.2% met the recommended post-treatment care. Younger age at diagnosis, white race, married, advanced stage, fewer comorbidities, and chemotherapy use were significantly associated with guideline adherence.^ In conclusions, not all colon cancer patients received chemotherapy. Receiving chemotherapy was associated with increased risk of developing gastrointestinal, hematological and cardiac toxicities. Patients were more likely to comply with the schedule for office visits and colonoscopy but failed in CEA tests. ^

Outcomes associated with chemotherapy in elderly patients with early stage operable breast cancer

Background. Various clinical trials have proved the efficacy of adjuvant chemotherapy in women with breast cancer. Chemotherapy efficacy and guidelines for its use differ by stage of tumor and age of the patient with no clear recommendations for patients aged 70 and above. Objective. To examine the clinical and economic outcomes associated with chemotherapy use in and to examine the disparities in treatment and survival in elderly patients with early stage operable breast cancer by age and axillary node status. Methods. We studied a cohort of 23,110 node positive and 31,572 node negative women aged 65 and over diagnosed with incident American Joint Committee on Cancer (AJCC) stage I, II or IIIa breast cancer between January 1, 1991 and December 31, 2002 using SEER-Medicare data. Total patient costs were estimated using the phase of care approach and adjusted cost estimates were obtained from regression analysis using a 3% discount rate. Cox proportional hazard ratio of mortality was used to determine the effectiveness of chemotherapy. Propensity score approach was also used to minimize the bias associated with receipt of chemotherapy. To assess disparity in treatment, multivariate logistic regression analyses were performed to assess the relative odds of receiving surgery, chemotherapy and radiation after BCS for African Americans compared to Whites. Results. Regression adjusted cost estimates for all node positive patients receiving chemotherapy was approximately $2,300 and was significantly higher (p<0.05) than for patients not receiving chemotherapy. Mortality was significantly lower in node positive and node negative women aged 65-74 years receiving chemotherapy. There was a significant difference between African American and White women in receiving BCS and radiation after BCS; however this difference was explained by patient demographics, tumor characteristics and socioeconomic status (SES). African American node positive women were 21% less likely to receive chemotherapy than White women (OR, 0.79; CI, 0.68-0.92) in multivariate analysis. Conclusion. Chemotherapy is associated with increased survival in patients aged 65-74 and total costs attributable to chemotherapy differ by phase and age of the patient. Underutilization of systemic adjuvant chemotherapy in African American women requires attention and may serve as potential areas for appropriate intervention.^

Geographic variation in the utilization and survival associated with oxaliplatin chemotherapy in patients with stage III colon cancer

Background: Overall objectives of this dissertation are to examine the geographic variation and socio-demographic disparities (by age, race and gender) in the utilization and survival of newly FDA-approved chemotherapy agents (Oxaliplatin-containing regimens) as well as to determine the cost-effectiveness of Oxaliplatin in a large nationwide and population-based cohort of Medicare patients with resected stage-III colon cancer. Methods: A retrospective cohort of 7,654 Medicare patients was identified from the Surveillance, Epidemiology and End Results – Medicare linked database. Multiple logistic regression was performed to examine the relationship between receipt of Oxaliplatin-containing chemotherapy and geographic regions while adjusting for other patient characteristics. Cox proportional hazard model was used to estimate the effect of Oxaliplatin-containing chemotherapy on the survival variation across regions using 2004-2005 data. Propensity score adjustments were also made to control for potential bias related to non-random allocation of the treatment group. We used Kaplan-Meier sample average estimator to calculate the cost of disease after cancer-specific surgery to death, loss-to follow-up or censorship. Results: Only 51% of the stage-III patients received adjuvant chemotherapy within three to six months of colon-cancer specific surgery. Patients in the rural regions were approximately 30% less likely to receive Oxaliplatin chemotherapy than those residing in a big metro region (OR=0.69, p=0.033). The hazard ratio for patients residing in metro region was comparable to those residing in big metro region (HR: 1.05, 95% CI: 0.49-2.28). Patients who received Oxalipaltin chemotherapy were 33% less likely to die than those received 5-FU only chemotherapy (adjusted HR=0.67, 95% CI: 0.41-1.11). KMSA-adjusted mean payments were almost 2.5 times higher in the Oxaliplatin-containing group compared to 5-FU only group ($45,378 versus $17,856). When compared to no chemotherapy group, ICER of 5-FU based regimen was $12,767 per LYG, and ICER of Oxaliplatin-chemotherapy was $60,863 per LYG. Oxaliplatin was found economically dominated by 5-FU only chemotherapy in this study population. Conclusion: Chemotherapy use varies across geographic regions. We also observed considerable survival differences across geographic regions; the difference remained even after adjusting for socio-demographic characteristics. The cost-effectiveness of Oxaliplatin in Medicare patients may be over-estimated in the clinical trials. Our study found 5-FU only chemotherapy cost-effective in adjuvant settings in patients with stage-III colon cancer.^

CHARACTERIZATION OF ALPHA-GALACTOSYLCERAMIDE AS A MUCOSAL ADJUVANT

Adjuvants are essential components of vaccine formulations that enhance adaptive immune responses to antigens, particularly for immunizations targeting the tolerogenic mucosal tissues, which are more biologically relevant for protective immunity against pathogens transmitted by the mucosal routes. Adjuvants possess the inherent capacity to bridge innate and adaptive immune responses through activating innate immune mediators. Here evidence is presented in support of the effectiveness of a synthetic glycolipid, alpha-Galactosylceramide (-GalCer), as an adjuvant for mucosal immunization with peptide and protein antigens, by oral and intranasal routes, to prime antigen-specific immune responses in multiple systemic and mucosal compartments. The adjuvant activity of -GalCer delivered by the intranasal route was manifested in terms of potent activation of NKT cells, an important innate immunity mediator, along with the activation of dendritic cells (DC) which serve as the professional antigen-presenting cells. Data from this investigation provide the first evidence for mucosal delivery as an effective means to harness the adjuvant potential of α-GalCer for priming as well as boosting cellular immune responses to co-administered immunogens. Unlike systemic administration where a single dose of α-GalCer leads to anergy of responding NKT cells and thus hinders delivery of booster immunizations, we demonstrated that administration of multiple doses of α-GalCer by the intranasal route affords repeated activation of NKT cells and the induction of broad systemic and mucosal immunity. This is specifically advantageous, and may be even essential, for vaccination regimens against mucosal pathogens such as the human immunodeficiency virus (HIV) and the human papillomavirus (HPV), where priming of durable protective immunity at the mucosal portals of pathogen entry would be highly desirable.

Specific, Reversible Cytostatic Protection of Normal Cells Against Negative Effects of Chemotherapy

Chemotherapy is a common and effective method to treat many forms of cancer. However, treatment of cancer with chemotherapy has severe side effects which often limit the doses of therapy administered. Because some cancer chemotherapeutics target proliferating cells and tissues, all dividing cells, whether normal or tumor, are affected. Cell culture studies have demonstrated that UCN-01 is able to reversibly and selectively arrest normal dividing cells; tumor cells lines do not undergo this temporary arrest. Following UCN-01 treatment, normal cells displayed a 50-fold increase in IC50 for camptothecin; tumor cells showed no such increased tolerance. We have examined the response of the proliferating tissues of the mouse to UCN- 01 treatment, using the small bowel epithelium as a model system. Our results indicate that UCN-01 treatment can cause a cell cycle arrest in the gut epithelium, beginning 24 hours following UCN-01 administration, with cell proliferation remaining suppressed for one week. Two weeks post-UCN-01 treatment the rate of proliferation returns to normal levels. 5-FU administered during this period demonstrates that UCN-01 is able to provide protection to normal cells of the mouse within a narrow window of efficacy, from three to five days post-UCN-01. UCN-01 pretreated mice displayed improved survival, weight status and blood markers following 5-FU compared to control mice, indicating that UCN-01 can protect normal dividing tissues. The mechanism by which UCN-01 arrests normal cells in vivo was also examined. We have demonstrated that UCN-01 treatment in mice causes an increase in the G1 phase cell cycle proteins cdk4 and cyclin D, as well as the inhibitor p27. Phosphorylated Rb was also elevated in the arrested cells. These results are a departure from cell culture studies, in which inhibition of G1 phase cyclin dependent kinases led to hyposphosphorylation of Rb. Future investigation will be required to understand the mechanism of UCN-01 action. This is important information, especially for identification of alternate compounds which could provide the protection afforded by UCN-01.

Long-term survival after multidisciplinary management of resected pancreatic adenocarcinoma.

INTRODUCTION: Actual 5-year survival rates of 10-18% have been reported for patients with resected pancreatic adenocarcinoma (PC), but the use of multimodality therapy was uncommon in these series. We evaluated long-term survival and patterns of recurrence in patients treated for PC with contemporary staging and multimodality therapy. METHODS: We analyzed 329 consecutive patients with PC evaluated between 1990 and 2002 who underwent resection. Each received a multidisciplinary evaluation and a standard operative approach. Pre- or postoperative chemotherapy and/or chemoradiation were routine. Surgical specimens of 5-year survivors were re-reviewed. A multivariate model of factors associated with long-term survival was constructed. RESULTS: Patients underwent pancreaticoduodenectomy (n = 302; 92%), distal (n = 20; 6%), or total pancreatectomy (n = 7; 2%). A total of 108 patients (33%) underwent vascular reconstruction, 301 patients (91%) received neoadjuvant or adjuvant therapy, 157 specimens (48%) were node positive, and margins were microscopically positive in 52 patients (16%). Median overall survival and disease-specific survival was 23.9 and 26.5 months. Eighty-eight patients (27%) survived a minimum of 5 years and had a median overall survival of 11 years. Of these, 21 (24%) experienced recurrence, 7 (8%) after 5 years. Late recurrences occurred most frequently in the lungs, the latest at 6.7 years. Multivariate analysis identified disease-negative lymph nodes (P = .02) and no prior attempt at resection (P = 0.01) as associated with 5-year survival. CONCLUSIONS: Our 27% actual 5-year survival rate for patients with resected PC is superior to that previously reported, and it is influenced by our emphasis on detailed staging and patient selection, a standardized operative approach, and routine use of multimodality therapy.

Dual Targeting of Tumor Angiogenesis and Chemotherapy by Endostatin- Cytosine Deaminase-Uracil PhosphoribosylTransferase

Antiangiogenesis is a promising anti-tumor strategy through inhibition tumor vascularformation to suppress tumor growth. Targeting specific VEGF/R has been showntherapeutic benefits in many cancer types and become a first approvedantiangiogenic modalities by Food and Drug Administration (FDA) in United States.However, interruption of homeostasis in normal tissues that is likely due to theinhibition of VEGF/R signaling pathway induces unfavorable side effects. Moreover,cytostatic nature of antiangiogenic drugs frequently causes less tumor cell specifickilling activity, and cancer cells escaped from cell death induced by these drugseven gain more malignant phenotypes, resulting in tumor invasion and metastasis.To overcome these issues, we developed a novel anti-tumor therapeutic EndoCDfusion protein which linked endostatin (Endo) to cytosine deaminase-uracilvphosphoribosyl transferase (CD). Endo targets unique tumor endothelial cells toprovide tumor-specific antiangiogenesis activity and also carries CD to the localtumor area, where it serves nontoxic prodrug 5-fluorocytosine (5-FC) enzymaticconversion reaction to anti-metabolite chemotherapy drug 5-fluorouracil (5-FU). Wedemonstrated that 5-FU concentration was highly increased in tumor sites, resultingin high level of endothelial cells and tumor cells cytotoxic efficacy. Furthermore,EndoCD/5-FC therapy decreased tumor growth and colorectal liver metastasisincident compared with bevacizumab/5-FU treatment in human breast and colorectalliver metastasis orthotropic animal models. In cardiotoxicity safety profile,EndoCD/5-FC is a contrast to bevacizumab/5-FU; lower risk of cardiotoxicityinduction or heart function failure was found in EndoCD/5-FC treatment thanbevacizumab/5-FU does in mice. EndoCD/5-FC showed more potent therapeuticefficacy with high safety profile and provided stronger tumor invasion or metastasisinhibition than antiangiogenic drugs. Together, EndoCD fusion protein with 5-FCshowed dual tumor targeting activities including antiangiogenesis and tumor localchemotherapy, and it could serve as an alternative option for antiangiogenic therapy.

Prognostic significance of xCT polymorphisms and expression in patients with advanced pancreatic cancer treated with chemotherapy

The plasma membrane xc- cystine/glutamate transporter mediates cellular uptake of cystine in exchange for intracellular glutamate and is highly expressed by pancreatic cancer cells. The xCT gene, encoding the cystine-specific xCT protein subunit of xc-, is important in regulating intracellular glutathione (GSH) levels, critical for cancer cell protection against oxidative stress, tumor growth and resistance to chemotherapeutic agents including platinum. We examined 4 single nucleotide polymorphisms (SNPs) of the xCT gene in 269 advanced pancreatic cancer patients who received first line gemcitabine with or without cisplatin or oxaliplatin. Genotyping was performed using Taqman real-time PCR assays. A statistically significant correlation was noted between the 3' untranslated region (UTR) xCT SNP rs7674870 and overall survival (OS): Median survival time (MST) was 10.9 and 13.6 months, respectively, for the TT and TC/CC genotypes (p = 0.027). Stratified analysis showed the genotype effect was significant in patients receiving gemcitabine in combination with platinum therapy (n = 145): MST was 10.5 versus 14.1 months for the TT and TC/CC genotypes, respectively (p = 0.013). The 3' UTR xCT SNP rs7674870 may correlate with OS in pancreatic cancer patients receiving gemcitabine and platinum combination therapy. Paraffin-embedded core and surgical biopsy tumor specimens from 98 patients with metastatic pancreatic adenocarcinoma were analyzed by immunohistochemistry using an xCT specific antibody. xCT protein IHC expression scores were analyzed in relation to overall survival in 86 patients and genotype in 12 patients and no statistically significant association was found between the level of xCT IHC expression score and overall survival (p = 0.514). When xCT expression was analyzed in terms of treatment response, no statistically significant associations could be determined (p = 0.908). These data suggest that polymorphic variants of xCT may have predictive value, and that the xc- transporter may represent an important target for therapy in pancreatic cancer.

Effect of cancer chemotherapy on the frequency of minisatellite repeat number changes in human sperm

The objective of this study was to determine whether cancer chemotherapy induces detectable mutations in DNA of the human germline and whether minisatellite repeat number changes can be used as a sensitive indicator of genetic damage in human sperm caused by mutagens. We compared the mutation frequencies in sperm of the same cancer patients pre- and post-, pre- and during, or during and post-treatment. Small pool polymerase chain reaction (SP-PCR) (DNA equivalent to approximately 100 sperm) and Southern blotting techniques were used to detect mutations and quantify the frequency of repeat number changes at the minisatellite MS205 locus. One pre- and one post-treatment semen sample was obtained from each Hodgkin's disease patient treated with either: (1) a regimen without alkylating agents, Novantrone, Oncovin, Vinblastine, and Prednisone (NOVP), 4 patients; (2) a regimen containing alkylating agents, Cytoxan, Vinblastine, Procarbazine, and Prednisone (CVPP)/Adriamycin, Bleomycin, DTIC, CCNU, and Prednisone (ABDIC), 2 patients; and (3) a regimen containing alkylating agents, Mechlorethamine, Oncovin, Procarbazine, and Prednisone (MOPP), 1 patient. One pre- and one during treatment semen sample from each of two Hodgkin's disease patients treated with Adriamycin, Bleomycin, Vinblastine, and Dacarbazine (ABVD) were obtained. One during and one post-treatment semen sample from a Hodgkin's disease patient treated with NOVP were also obtained. At least 7900 sperm in each sample were screened for the repeat number changes at the MS205 locus by multi-aliquots of SP-PCR. The mutation frequencies of pre- and post-treatment for the four patients treated with NOVP were 0.22 and 0.18%; 0.24 and 0.16%; 0.35 and 0.28%; and 0.19 and 0.18%. With CVPP/ABDIC, they were 0.22 and 0.23%; and 0.94 and 0.98% for the two patients and with MOPP they were 0.79 and 1.14%. The mutation frequencies of pre- and during treatment with ABVD were 0.09 and 0.07%; and 0.34 and 0.27% for the two patients. The mutation frequencies of during and post-treatment with NOVP for one patient were 0.31 and 0.25%. A statistically significant increase in mutation frequency was only found in the patient treated with MOPP. According to the time of samples collected after or during treatment and the above results, we conclude that there is no effect of NOVP and CVPP/ABDIC regimens on the mutation frequency in spermatogonia. The spermatocytes are not highly sensitive to chemotherapy agents compared to spermatogonia at the minisatellite MS205 locus. MOPP treatment may increase the mutation frequency at the MS205 locus in spermatogonia. ^

TUMOR PROGRESSION: ANALYSIS OF THE INSTABILITY OF THE METASTATIC PHENOTYPE, SENSITIVITY TO RADIATION AND CHEMOTHERAPY (PHENOTYPIC DRIFT, BREAST CANCER)

The major complications for tumor therapy are (i) tumor spread (metastasis); (ii) the mixed nature of tumors (heterogeneity); and (iii) the capacity of tumors to evolve (progress). To study these tumor characteristics, the rat 13762NF mammary adenocarcinoma was cloned and studied for metastatic properties and sensitivities to therapy (chemotherapy, radiation and hyperthermia). The cell clones were heterogeneous and no correlation between metastatic potential and therapeutic sensitivities was observed. Further, these phenotypes were unstable during passage in vitro; yet, the changes were clone dependent and reproducible using different cryoprotected cell stocks. To understand the phenotypic instability, subclones were isolated from low and high passage cell clones. Each subclone possessed a unique composite phenotype. Again, no apparent correlation was seen between metastatic potential and sensitivity to therapy. The results demonstrated that (1) tumor cells are heterogeneous for multiple phenotypes; (2) tumor cells are unstable for multiple phenotypes; (3) the magnitude, direction and time of occurrence of phenotypic drift is clone dependent; (4) the sensitivity of cell clones to ionizing radiation (gamma or heat) and chemotherapy agents is independent of their metastatic potential; (5) shifts in metastatic potential and sensitivity to therapy may occur simultaneously but are not linked; and (6) tumor cells independently diverge to form several subpopulations with unique phenotypic profiles. ^

Prime and boost vaccination against HER2/neu in breast cancer

Breast cancer is the most common cancer among women with approximately 180,000 new cases being diagnosed yearly in the United States (1). HER2/neu gene amplification and subsequent protein overexpression is found in 20–30% of breast cancer patients and can lead to the promotion of various metastasis-related properties (2–4) and/or resistance to cancer therapies such as chemotherapy and radiation (5). ^ The protein product of the HER2/neu gene, p185, is a proven target for immunological therapy. Recently, passive immunotherapy with the monoclonal antibody Trastuzumab® has validated an immunological approach to HER2/neu+ breast cancer. Immunity to HER2/ neu, when found in breast cancer patients, is of low magnitude. Vaccination-induced HER2/neu-specific antibodies and HER2/neu-specific cytotoxic T cells could result in long-lived immunity with therapeutic benefit. Many features of DNA vaccines and attenuated viral vectors may contribute to the efficacy of prime-boost vaccination. In particular, vaccines capable of eliciting strong cell-mediated immunity are thought to hold the greatest promise for control of cancer (6–9). ^ To optimize cellular immunization to HER2/neu in my study, the HER2/neu gene was presented to the immune system using a priming vector followed by a second vector used as the boost. In both animals and humans, priming with DNA and boosting with a poxviruses, vaccinia or canarypox appears to be particularly promising for induction of a broad immune responses (10). ^ I tested three gene vaccines encoding the HER2/neu gene: (1) a plasmid, SINCP, that contains part of the genome of Sindbis virus; (2) Viral Replicon Particles (VRP) of Venezuela Equine Encephalitis virus (VEE) and (3) E1/E2a-deleted human Type 5 Adenovirus. In SINCP and the VRP, the caspid and envelope genes of the virus were deleted and replaced with the gene for HER2/neu. SINCP-neu, VRP- neu and Adeno-neu when used alone were effective vaccines protecting healthy mice from challenge with a breast cancer cell line injected in the mammary fat pad or injected i.v. to induce experimental lung metastasis. However, SINCP-neu, VRP-neu or Adeno-neu when used alone were not able to prolong survival of mice in therapeutic models in which vaccination occurred after injection of a breast cancer cell line. ^ When the vaccines were combined in a mixed regimen of a SINCP- neu prime VRP-neu or Adeno-neu boost, there was a significant difference in tumor growth and survival in the therapeutic vaccine models. In vitro assays demonstrated that vaccination with each of the three vaccines induced IgG specific for p185, the gene product of HER2/neu, induced p185-specific T lymphocytes, as measured by tetramer analysis. Vaccination also induced intracellular INF-γ and a positive ELISPOT assay. These findings indicate that SINCP-neu, VRP-neu and Adeno-neu, used alone or in combination, may have clinical potential as adjuvant immunotherapy for the treatment of HER2/neu-expressing tumors. ^

Lactoferrin: An adjuvant to enhance the efficacy of the BCG vaccine

Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB), is a disease with world wide consequences, affecting nearly a third of the world's population. The established vaccine for TB; an attenuated strain of Mycobacterium bovis Calmette Guerin (BCG), has existed virtually unchanged since 1921. Intensive research is focused on developing a TB vaccine that can surpass and improve the existing BCG vaccine. Lactoferrin, an iron binding protein found in mucosal secretions and granules of neutrophils was hypothesized to be an ideal adjuvant to enhance the efficacy of the BCG vaccine. Specifically, Lactoferrin enhanced the ratio of IL-12:IL-10 production from macrophages stimulated with LFS or infected with BCG, indicating the potential to affect T-cell development in vivo. Five different vaccination protocols were investigated for generation of host protective responses against MTB infection using Lactoferrin admixed to the BCG vaccine. Mice immunized and boosted at 2 weeks with BCG/Lactofefrin increased host protection against MTB infection by decreasing organ bacterial load and reducing lung histopathology. The observed postchallenge results paralleled with increasing production of IFN-γ, IL-2, TNF-α, and IL-12 from BCG stimulated splenocytes. In vitro studies examined possible mechanisms of Lactoferrin action on BCG infected macrophages and dendritic cells. Addition of Lactoferrin to BCG infected macrophages and dendritic cells increased stimulation of presensitized CD3+ and CD4+ T-cells. Analysis by fluorescent activated cell sorting (FACS) revealed an increase in surface expression of MHC I and decreased ratio of CD80/86 from BCG infected macrophages cultured with Lactoferrin. In contrast, Lactoferrin decreased surface expression of MHC I, MHC II, CD80, CD86, and CD40, but increased CD 11c, from BCG infected dendritic cells, indicating involvement of adhesion molecules. Overall, these studies indicate that Lactoferrin is a useful and effective adjuvant to improve efficacy of the BCG vaccine by enhancing generation of mycobacterial antigen specific T-cell responses through promotion of antigen presentation and T-cell stimulation.^

Response to chemotherapy, recurrence and survival in advanced-stage ovarian, fallopian tube and primary peritoneal cancer patients with non-Ashkenazi Jewish BRCA mutations, compared to those without

Objectives. Previous studies have shown a survival advantage in ovarian cancer patients with Ashkenazi-Jewish (AJ) BRCA founder mutations, compared to sporadic ovarian cancer patients. The purpose of this study was to determine if this association exists in ovarian cancer patients with non-Ashkenazi Jewish BRCA mutations. In addition, we sought to account for possible "survival bias" by minimizing any lead time that may exist between diagnosis and genetic testing. ^ Methods. Patients with stage III/IV ovarian, fallopian tube, or primary peritoneal cancer and a non-Ashkenazi Jewish BRCA1 or 2 mutation, seen for genetic testing January 1996-July 2007, were identified from genetics and institutional databases. Medical records were reviewed for clinical factors, including response to initial chemotherapy. Patients with sporadic (non-hereditary) ovarian, fallopian tube, or primary peritoneal cancer, without family history of breast or ovarian cancer, were compared to similar cases, matched by age, stage, year of diagnosis, and vital status at time interval to BRCA testing. When possible, 2 sporadic patients were matched to each BRCA patient. An additional group of unmatched, sporadic ovarian, fallopian tube and primary peritoneal cancer patients was included for a separate analysis. Progression-free (PFS) & overall survival (OS) were calculated by the Kaplan-Meier method. Multivariate Cox proportional hazards models were calculated for variables of interest. Matched pairs were treated as clusters. Stratified log rank test was used to calculate survival data for matched pairs using paired event times. Fisher's exact test, chi-square, and univariate logistic regression were also used for analysis. ^ Results. Forty five advanced-stage ovarian, fallopian tube and primary peritoneal cancer patients with non-Ashkenazi Jewish (non-AJ) BRCA mutations, 86 sporadic-matched and 414 sporadic-unmatched patients were analyzed. Compared to the sporadic-matched and sporadic-unmatched ovarian cancer patients, non-AJ BRCA mutation carriers had longer PFS (17.9 & 13.8 mos. vs. 32.0 mos., HR 1.76 [95% CI 1.13–2.75] & 2.61 [95% CI 1.70–4.00]). In relation to the sporadic- unmatched patients, non-AJ BRCA patients had greater odds of complete response to initial chemotherapy (OR 2.25 [95% CI 1.17–5.41]) and improved OS (37.6 mos. vs. 101.4 mos., HR 2.64 [95% CI 1.49–4.67]). ^ Conclusions. This study demonstrates a significant survival advantage in advanced-stage ovarian cancer patients with non-AJ BRCA mutations, confirming the previous studies in the Jewish population. Our efforts to account for "survival bias," by matching, will continue with collaborative studies. ^

The role of reactive astrocytes in the resistance of melanoma brain metastasis to chemotherapy

Brain metastasis is resistant to chemotherapy while the leaky blood-brain-barrier in brain metastasis can not be the underlying reason. Metastatic tumor cells (“seed”) exploit the host microenvironment (“soil”) for survival advantages. Astrocytes which maintain the homeostasis of the brain microenvironment become reactive subsequent to brain damages and protect neurons from various injuries. We observed reactive astrocytes surrounding and infiltrating into brain metastasis in both clinical specimen and experimental animal model, thus raising a possibility that reactive astrocytes may protect tumor cells from cytotoxic chemotherapeutic drugs. ^ To test this hypothesis, we first generated an immortalized astrocyte cell line from H-2Kb-tsA58 mice. The immortal mouse astrocytes expressed specific markers including GFAP. Scanning electron microscopy demonstrated that astrocytes formed direct physical contact with tumor cells. Moreover, the expression of GFAP by astrocytes was up-regulated subsequent to co-culture with tumor cells, indicating that the co-culture of astrocytes and tumor cells may serve as a model to recapitulate the pathophysiological situation of brain metastasis. ^ In co-culture, astrocytes dramatically reduced apoptosis of tumor cells produced by various chemotherapeutic drugs. This protection effect was not because of culturing cells from different species since mouse fibroblasts did not protect tumor cells from chemotherapy. Furthermore, the protection by astrocytes was completely dependent on a physical contact. ^ Gap junctional communication (GJC) served as this physical contact. Tumor cells and astrocytes both expressed the major component of gap junctional channel—connexin 43 and formed functional GJC as evidenced by the “dye transfer” assay. The blockage of GJC between tumor cells and astrocytes by either specific chemical blocker carbenoxolone (CBX) or by genetically knocking down connexin 43 on astrocytes reversed the chemo-protection. ^ Calcium was the signal molecule transmitted through GJC that rescued tumor cells from chemotherapy. Accumulation of cytoplasmic calcium preceded the progress of apoptosis in tumor cells treated with chemotherapeutic drugs. Furthermore, chelation of accumulated cytoplasmic calcium inhibited the apoptosis of tumor cells treated with chemotherapeutic drugs. Most importantly, astrocytes could “shunt” the accumulated cytoplasmic calcium from tumor cells (treated with chemotherapeutic drug) through GJC. We also used gene expression micro-array to investigate global molecular consequence of tumor cells forming GJC with astrocytes. The data demonstrated that astrocytes (but not fibroblasts), through GJC, up-regulated the expressions of several well known survival genes in tumor cells. ^ In summary, this dissertation provides a novel mechanism underlying the resistance of brain metastasis to chemotherapy, which is due to protection by astrocytes through GJC. Interference with the GJC between astrocytes and tumor cells holds great promise in sensitizing brain metastasis to chemotherapy and improving the prognosis for patients with brain metastasis. ^