Racial disparities in chronic lymphocytic leukemia/small lymphocytic lymphoma accounting for small molecule inhibitors: A real-world cohort analysis

Kaplan-Meier curve depicting overall survival from CLL treatment start by race. For patients with CLL, no overall survival difference was observed between races in this real-world US database.

Immune-Related Gene Expression and Cytokine Secretion Is Reduced Among African American Colon Cancer Patients

Background: Colorectal cancer is the third most deadly cancer among African Americans (AA). When compared to Caucasian Americans (CA), AA present with more advanced disease and lower survival rates. Here, we investigated if differences in tumor immunology could be contributive to disparities observed between these populations.

Methods: We examined gene expression of tumor and non-tumor adjacent tissues from AA and CA by whole transcriptome sequencing, and generated scores for immune cell populations by NanoString. In addition, we utilized “The Cancer Genome Atlas” (TCGA) database from AA and CA as a validation cohort. Finally, we measured the secretion of cytokines characteristic of effector T helper cell (T_h) subsets by ELISA using plasma from each AA and CA participant.

Results: Colon tumors from AA patients showed significant fold-change increase in gene expression when compared to CA for FOXP3 (6.22 vs. 3.22), IL1B (103 vs. 11.4) and IL8 (220 vs. 28.9) (p < 0.05). In contrast, among CA we observed statistically higher gene expression of markers associated with antitumor activity such as GZMB (Granzyme B), IFNG and the immunotherapy targets PDL1 (CD274) and CTLA4 (p < 0.05). TCGA data validated our observed higher gene expression of GZMB and PDL1 in CA patients when compared to AA. Notably, our observations on immune cell populations show that AA tumors have significantly higher number of exhausted CD8+ cells (p < 0.01), mast cells (p < 0.02) and increased T regulatory cells when compared to CA. AA colon cancer patients differed from CA in cytokine production patterns in plasma (i.e., reduced IL-12).

Conclusions: Our study demonstrates significant differences of the immunological profiles of colon tumors from AA compared to CA that suggest a deficiency of appropriate immune defense mechanisms in terms of gene expression, recruitment of immune cells and systemic secretion of cytokines. As such, these immune differences could be mitigated through population-specific therapeutic approaches.

Abstract B059: African American pancreatic cancer microRNAs profile to identify links to drug resistance and tumor progression

Pancreatic cancer is a deadly disease with only 8% of the patients surviving 5 years (1). Recent data published for African Americans (AA) showed that this population has the highest death rate and shortest survival of any racial/ethnic group in the US for most cancers (2). The causes of this disparity are unknown; some of them may be socioeconomic as well as barriers to high-quality cancer prevention, early detection, and treatment information and services. It is clear that there is a gap between AA and Caucasian Americans (CA) concerning the development and death from pancreatic cancer. We hypothesize that there also are molecular differences in the tumors from AA and CA patients that contribute to this disparity. Importantly, The Cancer Genome Atlas (TCGA) numbers for pancreatic cancer reveals that only 7 out of 185 cases of pancreatic cancer are from African American patients. This clearly shows a prominent under-representation of tumor-related genetic information for the AA population. MicroRNAs (miRNAs) are able to regulate dozens of targets, especially those involved in cancer, making them a potential tool to study differences between populations. It is known that patients develop drug resistance against gemcitabine and one factor could be due to differential expression of miRNAs (3). The analysis of potential miRNA differences in AA and CA tumors would be a starting point to study the function(s) and mechanisms to understand the gap between these populations. We analyzed the tumor miRNAs expression of the TCGA 7 AA patients and compared the expression with 10 CA patients from TCGA to understand the main differences in expression between the two sets of samples. Using R studio, we found 26 miRNAs significantly different between CA and AA tumors. Some of them are involved in pathways related with tumor progression, cell invasion and tumor growth. We are interested in miRNAs involved in upregulating drug resistance against gemcitabine such as miR21, miR 155, or miR 196 as well as those miRNAs that dowregulate resistance to treatment like miR148, miR200 or miR34. Importantly, these miRNAs have been defined only in CA pancreatic tumor samples. We are collecting retrospective pancreatic cancer cases at SUNY Downstate Medical Center and Kings County Hospital Center to study the expression of miRNAs using Illumina technology in our AA population in Brooklyn, NY. These tissues will be matched for age, gender, body mass index, and for stage and site of disease to the best of our ability. Adjacent normal tissues will serve as standard controls. We will use CA PDAC cases from TCGA for comparison. This work is in progress. In conclusion, we found in our analysis 26 miRNAs differentially expressed between AA and CA using TCGA data. We expect to see a difference in expression of miRNAs using samples from our patient population. In addition, we are interested to see if our patients have a different expression pattern of miRNAs related to drug resistance and if this could explain the poor response often seen in AA PDAC patients.

Citation Format: Maria Munoz-Sagastibelza, Mohamed Alshal, Sayed Imtiaz, Jenny E. Paredes Sanchez, Mubarak Akadri, Raavi Gupta, Maksim Agaronov, Ellen Li, Jovanny Zabaleta, Laura Martello-Rooney. African American pancreatic cancer microRNAs profile to identify links to drug resistance and tumor progression [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr B059.

Abstract C118: Tumor immune response in colon cancer African American patients and its role in cancer disparities

Introduction: Colorectal cancer (CRC) is the third most common cancer among African Americans (AA) and when compared to Caucasian Americans (CA), they present more advanced CRC disease and lower survival rates. Our previous findings suggest that this may be related to the differential expression in genes linked to cell recruitment and immune response. Therefore, we aimed to investigate the cellular antitumor activity and mutational profile of colon tumors from AAs. We also examined the secretion of cytokines characteristic of immune responses by different effector T helper cells (Th) subsets in AA and CA patients, as well as cell lines, to see if these differences play a role in the health disparities observed between these populations. Lastly, we observed the expression of the Program Death Ligand 1 (PD-L1) in response to the cytokines IL-17A and TNF-α in a microsatellite-unstable (MSI) AA and a microsatellite-stable (MSS) CA colon cancer cell line.

Methods: Using IHC, we evaluated the cell recruitment and activation of T and natural killer cells in AA tumors. For mutational analysis, we utilized the TruSight Tumor 170 RUO kit (Illumina). ELISA assays (RayBiotech) were used to examine the secretion of cytokines linked to Th subsets (Th1, Th2, Th17) and inflammation in plasma from the AA and CA CRC patients, as well as in supernatants from the AA and CA colon cancer cell lines. Western blots were used to observe the expression of PD-L1 in the in vitro models.

Results: ELISAs of plasma of CA and AA patients revealed a differential Th cytokines production patterns between early-stages (I, II) and late-stage (III) disease. The MSI AA cell line showed an increase on PD-L1 protein expression in response to IL-17A and TNF-α with an additive effect when combined in equal concentrations. Lastly, the mutational sequencing allowed us to further investigate the potential alterations that are responsible for the differences that we observed in gene expression between AAs and CAs in our RNA and cytokine expression profiling.

Conclusions: Our results indicate that the immune profiles of AA patients differ from CA in terms of cytokines' production; AAs expressed elevated IL-17A, whereas CA expressed elevated IFN-γ, the latter indicative of Th1 immunity that has a more favorable prognosis. As such, these differences could be used as biomarkers and to guide therapeutic strategy for these populations. The mutational sequencing will help us to elucidate the impaired tumor immune response in AAs with colon cancer when compared to CAs that we observed in terms of cell recruitment and cytokine secretion in our previous findings. Importantly, our data indicate that IL-17A and TNF-α promote the protein production of PD-L1 in an MSI AA cell line, which may result in the impairment of T cells' antitumor activity. Taken together, the differences in the immunologic profiles in AA when compared to CA suggest a deficiency of the appropriate immune defense mechanisms in this population that may contribute to the cancer health disparities among CRC patients.

Citation Format: Jenny E. Paredes, Ping Ji, Jone Garai, Marzia Spagnardi, Maria Munoz-Sagastibelza, Sayed Imtiaz, Gayle Mendez, Mubarak Akadri, Raavi Gupta, Mohamed Alshal, Maksim Agaronov, Henry Talus, Ellen Li, Jovanny Zabaleta, Laura Martello-Rooney, Jennie Williams. Tumor immune response in colon cancer African American patients and its role in cancer disparities [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr C118.

Evaluation of the feasibility of intrapancreatic delivery of drug-loaded microparticles via EUS-guided fine needle injection using a swine model

Background and study aims  Patients with pancreatic cancer often have locally advanced or metastatic disease and are not candidates for curative surgery. Polymer-based microparticles (MPs) represent a drug delivery system that offers sustained release of a chemotherapeutic drug after intralesional injection for local tumor management. The aim of this study was to determine the feasibility of endoscopic ultrasound-guided fine-needle injection (EUS-FNI) of drug-loaded MPs tagged with a fluorophore and fiducial markers for locating the injection site. Secondary aims were to determine the tissue-specific effects of MPs. Methods  Five pigs underwent EUS with selection of an injection site within the pancreas that was marked by placing fiducial markers prior to the MPs injection. EUS-FNI of either blank microparticles (BMPs), containing no drug, or gemcitabine-loaded microparticles (GMPs) was performed. A saline flush containing Spot Endoscopic Marker was used to expel any residual MPs in the needle shaft and tattoo the injection site. Results  A green fluorescent protein flashlight was used to successfully identify the site of MP injection sites in the dissected pancreas. Frozen sections of pig pancreas demonstrated a defined deposit, confirming the delivery of the MPs. Finally, fluorescence microscopy showed activation of caspase-mediated cell death in pancreases of animals that received injections of GMPs. Conclusions  This pilot study demonstrated that fiducial marker placement and pancreatic EUS-FNI of MPs was successful in all pigs with no animals demonstrating pancreatitis. Further studies are needed to determine the role for intralesional injection of drug-loaded MPs in borderline resectable or unresectable pancreatic cancer.

Abstract 152: Gene expression and mutational load in colon tumors from African American patients

Colorectal cancer (CRC) is the third most common cancer among African Americans (AA) and when compared to Caucasian Americans (CA), they present with more advanced disease and lower survival rates. Our previous findings suggest that this may be related to the differential expression of genes linked to cell recruitment and immune response. Therefore, we aimed to investigate if differences in the cellular anti-tumor immune activity in AA and CA patients play a role in the disparate cancer progression observed between these populations. Our approach includes examining gene expression and immune cell recruitment at the tumor site and secretion of cytokines characteristic of effector T helper cells (Th) subsets in plasma. Lastly, we observed the expression of several proteins involved in apoptosis, stress, and drug resistance in response to treatment with 5-FU in two microsatellite unstable (MSI) CRC cell lines, one from an AA and one from a CA patient, and a microsatellite stable (MSS) CA colon cancer cell line.

Methods: We performed whole transcriptome sequencing in colon tumors, utilizing the NextSeq 500/550 High Output Kit v2.5 (Illumina). ELISA assays (RayBiotech) were used to examine the secretion of cytokines linked to Th subsets (Th1, Th2, Th17) and inflammation in plasma. Using IHC we evaluated the cell recruitment and activation of T and Natural Killer cells in colon tumors and by MetaCore we correlated gene expression to immune-oncology pathways. Western blots were used to evaluate the expression of cleaved caspase 3, phospho-JNK and RRM1 in the in-vitro models.

Results: ELISAs of plasma from CA and AA patients revealed a differential Th cytokines production patterns between early stage (I, II) and late stage (III) disease. Our gene expression results indicate that the immune profiles of AA patients differ from CA in the expression of 36 key genes and cytokines related to cellular anti-tumor activity, including FOXP3, Granzyme B and IL-17A, suggestive of more favorable prognosis in the CA tumors. Lastly, the MSI AA cell line showed sensitivity to 5-FU in terms of protein expression when compared to the CA cell lines.

Conclusions: Our gene expression findings demonstrated the differential expression of immunological pathways involved in immune-surveillance, cancer progression and antigen presentation in colon tumors from these two ethnicities. These results were in accordance with the systemic cytokines’ expression patterns observed in plasma and cell recruitment to the tumor sites. Importantly, our data indicates that treatment with 5-FU chemotherapy promotes apoptosis and stress in the MSI AA cell line but fails to produce the same effect in the CA cell lines at the same concentrations. Taken together, the differences in the immunological profiles in AA when compared to CA suggests a deficiency of the appropriate immune defense mechanisms in this population that may contribute to the cancer disparities among CRC patients.

Citation Format: Jenny Paredes, Jone Garai, Ping Ji, Sayed Imtiaz, Marzia Spagnardi, Maria Munoz-Sagastibelza, Mubarak Akadri, Raavi Gupta, Mohamed Alshal, Maksim Agaronov, Henry Talus, Ellen Li, Jennie Williams, Jovanny Zabaleta, Laura Martello-Rooney. Gene expression and mutational load in colon tumors from African American patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 152.

Abstract A73: Role of microsatellite stability and mismatch DNA repair mechanism in the response to 5-fluorouacil treatment in African American colon cancer cell lines

Despite progress in closing the gap, health disparities still persist among African American (AA) colon cancer patients both in incidence and death rates as well as worse prognosis after treatment with 5-fluorouacil (5-FU) when compared to Caucasian American (CA) patients. In addition, AA colon cancer patients have higher incidence of mutations on the mismatch DNA-repair mechanism (MMR) than CA patients, and previous studies have shown a correlation between mutations in MMR and microsatellite instability (MSI) to resistance to 5-FU. Therefore, we aim to examine if differential MSI and MMR play a role in the efficacy of 5-FU treatment in AAs.

Methods: We examined the microsatellite status and MMR mutations found in the tumors from AA colon cancer patients at our institution from 2010 to 2017 and utilized the AA tumor-derived colon cancer cell line SB-521, generated in Dr. Williams's laboratory, and the CA colon cancer cell line HT-29 for in vitro studies. In order to assess the response to 5-FU, we used the protein levels of the ribonucleotide reductase catalytic subunit M1 (RRM1) protein as a marker for drug resistance, the cleavage of caspase-3 for apoptosis initiation, c-Jun N-terminal kinases (JNK) phosphorylation as indicator of cellular stress, and histone 3 protein levels as reference of gene methylation changes.

Results: Our retrospective data (N=83 patients) demonstrated that up to 20% of our colon cancer patients have MSI and up to 30% showed MMR mutations. As hypothesized, the protein levels of the chosen targets in the two cell lines exhibited differences after treatment with 5-FU. The AA cell line SB-521 appears to be more sensitive to the chemotherapeutic in terms of apoptosis, stress response, and drug resistance when compared to HT-29 cells.

Conclusions: Altogether, our results illustrate the range of MSI, MMR, and protein patterns in AA tumors and cell line. The cell line SB-521 is a potential model to study 5-FU treatment for patients with MSI and MMR mutations as it has high MSI, does not express MLH1, has reduced MSH2, and overexpresses MSH6 (MMR proteins). Previous data suggest that lack of a functional MMR mechanism may play a role in the response to this chemotherapeutic. Further studies are needed to elucidate the differences in chemotherapy treatment responses between AAs and CAs and their role in colon cancer health disparities.

Citation Format: Jenny E. Paredes, Ping Ji, Maria Munoz-Sagastibelza, Malhaar Agrawal, Jennie Williams, Laura Martello-Rooney. Role of microsatellite stability and mismatch DNA repair mechanism in the response to 5-fluorouacil treatment in African American colon cancer cell lines [abstract]. In: Proceedings of the Tenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2017 Sep 25-28; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2018;27(7 Suppl):Abstract nr A73.

Abstract 3878: Drug-loaded microparticles as a treatment approach for pancreatic cancer

Pancreatic cancer is the fourth leading cause of cancer death in the United States with only 7% of diagnosed patients surviving 5 years. Most pancreatic cancer patients are not surgical candidates due to advanced stage at diagnosis. Also, current systemic chemotherapies have not been very effective at decreasing tumor burden. Poly(lactic-co-glycolic acid)-based (PLGA) microparticles (MPs) are a promising tool for localized drug delivery within the tumor due to their biocompatibility, flexibility in drug encapsulation and extended drug release. The present study investigated whether gemcitabine-loaded microparticles (GMPs), paclitaxel-loaded microparticles (PMPs) or sequential treatment of both, in comparison with blank (no drug) MPs, systemic treatments and no treatment control, are able to promote cancer cell killing effects and modulate drug resistance in vitro and in vivo. We previously showed in vitro studies with PANC-1 cells and we were able to complete the MPs studies with a second human pancreatic cancer cell line, MIAPaCa-2. In both cases, we tested the effect of single and combination treatments on two well-known resistance markers for gemcitabine, ribonucleotide reductase catalytic subunit M1 and cytidine deaminase, as well as on the promotion of cell death measuring cleaved caspase-3 (CC3). When treated with GMPs alone, both markers went up suggesting an increase in resistance against gemcitabine. Interestingly, both cell lines treated with PMPs alone showed an increase in CC3 expression and a significant decrease in the expression of both markers. Subsequently, we tested the in vivo efficacy of MPs by direct injection into established subcutaneous MIAPaCa-2 tumors in nude mice. Following four weeks of treatment, the tumors were excised, biopsied for protein analysis and frozen in OCT to allow visualization of fluorescent MPs and detect apoptosis by immunofluorescence. We also want to evaluate reactive oxygen species production; where we expect to see an increase in the MPs treated groups. This analysis is in progress. In conclusion, we observed a decrease in cell viability and drug resistance proteins in vitro using the drug-loaded microparticles in two grade 3 (or high grade) pancreatic cancer cell lines. The described drug delivery method has the potential to be a more efficient treatment modality than systemic gemcitabine and paclitaxel against early stage and locally advanced pancreatic cancer.

Citation Format: Maria Munoz-Sagastibelza, Oluwafeyikemi Okome, Jenny E. Paredes Sanchez, Albert Palileo, Catherine Burkhart, Laura Martello-Rooney. Drug-loaded microparticles as a treatment approach for pancreatic cancer [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 3878.

Abstract 646: Immune checkpoints and inflammation in colon tumors from African Americans

Colorectal cancer (CRC) is the third most common cancer among African Americans (AA) and when compared to Caucasian Americans (CA), they present more advanced CRC disease and lower survival rates. Recent findings suggest that this may be related to the differential expression in genes linked to inflammation and immune response. Therefore, we aimed to investigate if tumors from AA colon cancer patients diverge in their immunologic profile from CA and if the immune response of a CRC cell line derived from an AA tumor will differ from a CA CRC cell line. Additionally, we are recording the genetic profiles of colon tumors and outcomes from AA patients at our institution.

Methods: Using DESeq2 we evaluated the differential gene expression pattern by whole transcriptome sequencing (Illumina) of 10 CRC tissues (and matching adjacent non-tumor tissue) from both AA and CA individuals. We focused on genes involved in immune checkpoints and inflammation. We also examined the secretion of Interleukin 8 (IL-8) in plasma from our AA CRC patients. For the in vitro experiments, we used the AA tumor-derived colon cancer cell line SB-521, generated in Dr. Williams' laboratory, and the CA colon cancer cell line HT-29 to determine if the cell lines expressed the Programmed death-ligand 1 (PD-L1). Lastly, we analyzed the microsatellite (MSI) status and MMR mutations in tumors from AA colon cancer patients at our institution and correlated their genetic analysis to response to chemotherapies and survival.

Results: The genomic data revealed that AA and CA tumors had a significant difference of expression in a total of 221 genes. Remarkably, some of these genes included PD1, IL1B, IL17A, IL10, IL5, CD80 and FOXP3. The cytokine IL-8 concentration detected by ELISA in plasma of these patients revealed a differential expression between early stages (I, II) and late stages (III, IV). As hypothesized, the MSI and AA tumor-derived cell line SB-521 expressed PD-L1 and showed an increase in protein levels in response to TNF-α treatment (the CA cell line HT-29 did not express PD-L1). Lastly, our retrospective data (N=200 patients) demonstrated that up to 20% of our AA colon cancer patients have MSI and/or MMR mutations.

Conclusions: Altogether, our results suggest that the immune profiles of the tumors from AA patients differ from CA and these differences could be used as biomarkers and to guide therapeutic strategy for these populations. Also, since the AA cell line presented distinct inflammatory patterns and when compared to the HT-29 CA cell line, it is a potential model to study MSI and PD-L1 in AA. Hence, we aim to supplement our preliminary data on AA patients with MSI and MMR mutations at Downstate and to elucidate what other genomic differences exist and cytokines' secretion patterns observed. In conclusion, we will address the immune and molecular biology of CRC tumors in AA through genomic and in vitro studies, and generate patient's data on AA diagnosed with colon cancer.

Citation Format: Jenny E. Paredes, Ping Ji, Maria Munoz-Sagastibelza, Sayed Imtiaz, Kaylene Barrera, Raavi Gupta, Maksim Agaronov, Henry Talus, Jovanny Zabaleta, Jennie Williams, Laura Martello-Rooney. Immune checkpoints and inflammation in colon tumors from African Americans [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 646.

Successful creation of pancreatic cancer organoids by means of EUS-guided fine-needle biopsy sampling for personalized cancer treatment

BACKGROUND AND AIMS

Pancreatic cancer organoids are tumor models of individualized human pancreatic ductal adenocarcinoma (PDA), created from surgical specimens and used for personalized treatment strategies. Unfortunately, most patients with PDA are not operative candidates. Creation of human PDA organoids at the time of initial tumor diagnosis is therefore critical. Our aim was to assess the feasibility of creating human PDA organoids by EUS fine-needle biopsy (EUS-FNB) sampling in patients with PDA.

METHODS

In this prospective clinical trial in patients referred to evaluate a pancreatic mass, EUS-FNA was performed for initial onsite diagnosis. Two additional needle passes were performed with a 22-gauge FNB needle for organoid creation. Primary outcome was successful isolation of organoids within 2 weeks of EUS-FNB sampling (P0, no passages), confirmed by organoid morphology and positive genotyping.

RESULTS

Thirty-seven patients with 38 PDA tumors were enrolled. Successful isolation of organoids (P0) was achieved in 33 of 38 tumors (87%). Establishment of PDA organoid lines for ≥5 passages of growth (P5, five passages) was reached in 25 of 38 tumors (66%). In the single patient with successful P5 FNB sampling-derived and P5 surgically derived organoids, there was identical matching of specimens. There were no serious adverse events. Two patients developed bleeding at the EUS-FNB puncture site requiring hemostasis clips.

CONCLUSIONS

Pancreatic cancer organoids can be successfully and rapidly created by means of EUS-FNB sampling using a 22-gauge needle at the time of initial diagnosis. Successful organoid generation is essential for precision medicine in patients with pancreatic cancer in whom most are not surgically resectable. (Clinical trial registration number: NCT03140592.).

Abstract 1091: Paclitaxel-loaded microparticles in combination with gemcitabine-loaded microparticles decreases gemcitabine resistance and promotes cell death in pancreatic cancer cell lines

Pancreatic cancer is the fourth leading cause of cancer death in the United States with only 7% of diagnosed patients surviving 5 years. Current systemic chemotherapies have not been very effective at decreasing tumor burden, but nonetheless expose patients to the adverse side effects of treatment. Poly(lactic-co-glycolic acid)-based microparticles (MPs) are a promising tool for localized drug delivery within the tumor due to their high biocompatibility, flexibility in drug encapsulation and extended drug release. A previous in vivo experiment from our laboratory demonstrated minimal penetration of systemic gemcitabine into the tumor resulting in low levels of apoptosis compared to locally injected gemcitabine-loaded microparticles (GMPs), which demonstrated much higher levels of intratumoral apoptosis. The present study investigated whether paclitaxel-loaded microparticles (PMPs), alone or in combination with GMPs, decreased gemcitabine resistance, colony formation and promoted cell death in two human pancreatic cancer cell lines, PANC-1 and MIAPaCa-2. In vitro studies with PANC-1 cells treated with PMPs or GMPs showed enhanced cell killing and a significant decrease in colony formation in the higher MPs volume groups. Moreover, the combination treatment of PMPs followed by GMPs, showed a greater decrease in colony formation in comparison with the single treatments. Subsequently, we tested the effect of single and combination treatments on two well-known resistance markers for gemcitabine, ribonucleotide reductase catalytic subunit M1 (RRM1) and cytidine deaminase (CDA), as well as on the promotion of cell death measuring cleaved caspase-3 (CC3). Interestingly, PANC-1 cells treated with PMPs alone showed an increase in CC3 expression and a significant decrease in the expression of both markers when treated with different volumes of PMPs. MIAPaCa-2 cells exhibited similar results. The combination treatment also showed a modulation in RRM1 and CDA proteins and an increase in CC3 expression. However, when PANC-1 cells were treated with GMPs alone, both markers went up suggesting an increase in resistance against gemcitabine. These experiments are in progress for the MIAPaCa-2 cells. In addition, preliminary drug release studies with GMPs demonstrated detection of gemcitabine up to 14 days. In conclusion, our data demonstrated that PMPs and GMPs promote an increase in cancer cell death. Furthermore, the combination of the drug-loaded MPs indicated a reduction in drug resistance and clear impairment in colony formation. Further studies are in progress to investigate combination MPs injections in a mouse model of pancreatic cancer to confirm in vivo efficacy. The described drug delivery method has the potential to be a more efficient local treatment modality than systemic drug against pancreatic cancer.

Citation Format: Maria Munoz-Sagastibelza, Ariella Moshchinsky, Oluwafeyikemi Okome, Jenny E. Paredes Sanchez, Raavi Gupta, Laura Martello-Rooney. Paclitaxel-loaded microparticles in combination with gemcitabine-loaded microparticles decreases gemcitabine resistance and promotes cell death in pancreatic cancer cell lines [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 1091. doi:10.1158/1538-7445.AM2017-1091

Abstract C35: Differential inflammatory cytokine secretion between African American and Caucasian colon cancer cell lines

Colorectal cancer (CRC) incidence and mortality rates in African Americans (AAs) are up to 38% higher than in Caucasian Americans (CAs). Moreover, our previous studies reported that AAs have hypermethylated DNA regions in inflammatory genes such as NELL1, GDF1, ARHGEF4, and ITGA4; suggesting that AAs have differences in their inflammation patterns when compared to CAs. Therefore, we used two AA tumor-derived cell lines, which were generated in Dr. Williams' laboratory, and two CA tumor-derived cell lines to study the production of the pro-inflammatory IL-8 and anti-inflammatory IL-10 cytokines as they relate to possible differences in the inflammatory response. The inflammatory inducers IL-1B and TNF-alpha as well as Lipopolysaccharide from E. coli were used to mimic colonic inflammatory niches and induce cytokines secretion in these four cell lines. As hypothesized, our results show a significantly higher inflammatory cytokine production of IL-8 in the CA cell lines in response to all the treatments when compared to the AA cell lines. In contrast, secretion of IL-10 between the cell lines was within the same range. We could then propose that AA colon tumors secrete less IL-8 than CA colon tumors as a consequence of their DNA hypermethylated genes and this leads to deficient recruitment of neutrophils and macrophages, key cells for pathogen elimination and T cell activation. Further studies are needed to elucidate the differences in inflammation patterns between AAs and CAs and their role in CRC health disparities.

Citation Format: Jenny Elizabeth Paredes Sanchez, Maria Munoz-Sagastibelza, Ji Peing, Laura Martello-Rooney, Jennie Williams. Differential inflammatory cytokine secretion between African American and Caucasian colon cancer cell lines. [abstract]. In: Proceedings of the Ninth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2016 Sep 25-28; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2017;26(2 Suppl):Abstract nr C35.

Abstract B56: Paclitaxel-loaded microparticles promote cancer cell death and reduce gemcitabine resistance in a pancreatic cancer cell line

Pancreatic cancer is the fourth leading cause of cancer death in the United States with only 7% of diagnosed patients surviving 5 years. Most pancreatic cancer patients are not surgical candidates due to advanced stage at diagnosis. Current systemic chemotherapies, while exposing patients to the adverse side effects of treatment, have not been very effective at decreasing tumor burden primarily due to poor systemic drug uptake resulting from the dense stromal nature of pancreatic tumors. Poly (lactic-co-glycolic acid)-based microparticles (MPs) are a promising tool for localized drug delivery within the tumor due to their biocompatibility, flexibility in the encapsulation of different drugs and extended drug release inside the tumor. Previous studies in our laboratory with gemcitabine-loaded microparticles (GMPs) showed an enhanced cell killing effect against the PANC-1 and MIAPaCa-2 human pancreatic ductal adenocarcinoma cell lines. In addition, we tested the efficacy of these GMPs by direct injection into established subcutaneous MIAPaCa-2 tumors in nude mice. We observed a significant increase in apoptosis (p&lt;0.05) and a trending decrease in tumor volume in the GMPs-injected MIAPaCa-2 tumors compared to the blank microparticles-injected and control tumors.

Paclitaxel (PTX) is an FDA-approved drug to treat pancreatic cancer but the systemic toxicity restricts the dosing and therefore efficacy of the treatment. Recently, a new version of PTX, nab-paclitaxel, has been approved and exhibits increased effectiveness in a proportion of pancreatic cancer patients. It has been described that PTX improves gemcitabine effects, making them an attractive combination for treatment. The present study investigated whether paclitaxel-loaded microparticles (PMPs) in the range of 10-30 microns, as a single agent and in combination with GMPs, are able to promote cell death and overcome the resistance against gemcitabine in vitro.

For this study, we used the PANC-1 cell line, which is less sensitive to gemcitabine, to investigate the effect of PMPs on proteins involved in drug resistance by cancer cells prior to and during gemcitabine treatment, as well as potential cell death effects. Using different volumes of PMPs as a single agent, we observed a decrease in ribonucleotide reductase catalytic subunit M1 (RRM1) and in cytidine deaminase (CDA) protein expression, which are known resistance markers for gemcitabine in pancreatic cancer. In addition, cell viability was determined using Trypan Blue exclusion assay and we confirmed that the treatment significantly increased cell death in comparison with the control cells. We also observed an increase in cleaved-caspase 3 expression indicating engagement of the apoptotic cascade. Subsequently, we treated PANC-1 cells with a sequential combination of PMPs first followed by GMPs, and observed an effect of PTX on certain resistance proteins, as well as an increase in cell death when combining the MPs.

In conclusion, our data suggests that PMPs could reduce resistance barriers and, combined with GMPs, could enhance cancer cell death. Further studies are needed to investigate PMPs injections into established mouse tumors to confirm efficacy. The described drug delivery method has the potential to be a more efficient local treatment modality than systemic gemcitabine and paclitaxel against pancreatic cancer.

Citation Format: Maria Munoz-Sagastibelza, Laura Martello-Rooney.{Authors}. Paclitaxel-loaded microparticles promote cancer cell death and reduce gemcitabine resistance in a pancreatic cancer cell line. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2016 May 12-15; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(24 Suppl):Abstract nr B56.

Abstract 2070: Gemcitabine-loaded microparticles promote cancer cell death in subcutaneous pancreatic cancer xenografts

Pancreatic cancer is the fourth leading cause of cancer death in the United States with only 7% of diagnosed patients surviving 5 years. Most pancreatic cancer patients are not surgical candidates due to advanced stage at diagnosis. Current systemic chemotherapies, while exposing patients to the adverse side effects of treatment, have not been very effective at decreasing tumor burden primarily due to poor systemic drug uptake resulting from the dense stromal nature of pancreatic tumors. Poly(lactic-co-glycolic acid)-based (PLGA) microparticles (MPs) are a promising tool for localized drug delivery within the tumor due to their high biocompatibility, flexibility in the encapsulation of different drugs and extended drug release inside the tumor. The present study investigated whether gemcitabine-loaded microparticles (GMPs) in the range of 10-50 microns, in comparison with blank (no drug) MPs (BMPs), saline intraperitoneal injection (SIP) and gemcitabine intraperitoneal injection (GIP) as controls, are able to promote cancer cell killing effects in vivo.

In vitro studies with PANC-1 and MIAPaCa-2 human pancreatic adenocarcinoma cell lines treated with different PLGA co-polymer ratios used to encapsulate gemcitabine showed enhanced cell killing and decreased colony formation in the longer release co-polymer ratio after 2 weeks of treatment. Subsequently, the in vivo efficacy of GMPs was tested by direct injection of GMPs into established subcutaneous MIAPaCa-2 tumors in nude mice. Treatment commenced when tumor volume was approximately 250 mm3. Following two weeks of treatment, there was a trending decrease in tumor volume in the GMPs-injected MIAPaCa-2 tumors compared to the BMPs-injected tumors. When comparing the SIP to GIP groups, there was no difference in final tumor volume emphasizing the lack of effective penetration of systemic gemcitabine into the tumor. In addition, we observed less tumor progression in the GMPs group compared to the others. At the endpoint, the tumors were excised, frozen in OCT compound and sectioned to visualize fluorescent MPs and to detect apoptosis by immunofluorescence. Interestingly, we observed a significant increase in apoptosis in the tumors treated with GMPs compared to the BMP tumors (p&lt;0.05) as well as the SIP (p&lt;0.05) and GIP tumors (p&lt;0.05).

In conclusion, our data suggest that gemcitabine-loaded MPs could decrease tumor volume and increase local pancreatic tumor cell death. Further studies are needed to optimize the MPs loading and injection to confirm its efficacy. The described drug delivery method has the potential to be a more efficient local treatment modality than systemic gemcitabine against pancreatic cancer.

Citation Format: Maria Munoz-Sagastibelza, Vadim Kurbatov, Sophia Dynes, Jennifer Caceres, Michael Chen, Raavi Gupta, Catherine Burkhart, Laura Martello-Rooney. Gemcitabine-loaded microparticles promote cancer cell death in subcutaneous pancreatic cancer xenografts. [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 2070.