Bioactive compounds, antioxidant activity and antiproliferative effects in prostate cancer cells of green and roasted coffee extracts obtained by microwave-assisted extraction (MAE)

Coffee consumption has been investigated as a protective factor against prostate cancer. Coffee may be related to prostate cancer risk reduction due to its phytochemical compounds, such as caffeine, chlorogenic acids, and trigonelline. The roasting process affects the content of the phytochemicals and undesired compounds can be formed. Microwave-assisted extraction is an alternative to conventional extraction techniques since it preserves more bioactive compounds. Therefore, this study aimed to evaluate the phytochemical composition and the putative preventive effects in prostate cancer development of coffee beans submitted to four different coffee-roasting degrees extracted using microwave-assisted extraction. Coffea arabica green beans (1) were roasted into light (2), medium (3) and dark (4) and these four coffee samples were submitted to microwave-assisted extraction. The antioxidant capacity of these samples was evaluated by five different methods. Caffeine, chlorogenic acid and caffeic acid were measured through HPLC. Samples were tested against PC-3 and DU-145 metastatic prostate cancer cell lines regarding their effects on cell viability, cell cycle progression and apoptotic cell death. We found that green and light roasted coffee extracts had the highest antioxidant activity. Caffeine content was not affected by roasting, chlorogenic acid was degraded due to the temperature, and caffeic acid increased in light roasted and decreased in medium and dark roasted. Green and light roasted coffee extracts promoted higher inhibition of cell viability, caused greater cell cycle arrest in S and G₂/M and induced apoptosis more compared to medium and dark roasted coffee extracts and the control samples. Coffee extracts were more effective against DU-145 than in PC-3 cells. Our data provide initial evidence that among the four tested samples, the consumption of green and light coffee extracts contributes to inhibit prostate cancer tumor progression features, potentially preventing aspects related to advanced prostate cancer subtypes.

Abstract 3121: Osteopontin-c is overexpressed and mediates cell adhesion and proliferation in leukemia cell line with KMT2A-AFF1

Osteopontin (OPN) primary transcript suffers alternative splicing generating at least five OPN splicing isoforms (OPN-SI) named OPNa, OPNb, OPNc, OPN4 and OPN5. In solid tumors, total OPN (tOPN) expression has been correlated to several cancer features. However, OPN-SI roles in hematological malignancies are still under investigation. A hallmark of B-cell acute lymphoblastic leukemia (B-ALL) is the recurrence of specific gene rearrangements associated with prognostic risk stratification. Patients harbouring the KMT2A-AFF1 fusion gene are included into poor prognostic subgroup, with an overall survival rate of 50% and increased risk of extramedullary sites involvement. In B-ALL, it has been reported that tOPN support tumor dormancy and cell survival in response to chemotherapeutic drugs. However, the specific roles of OPN-SI have not been addressed. The aim of this study was to analyze the expression of OPN-SI in B-ALL samples and then investigate the role of the most overexpressed OPN-SI on modulating cellular and molecular aspects of B-ALL presenting KMT2A-AFF1. We found that OPNc is overexpressed in relation to OPNa and OPNb in patients with KMT2A-AFF1. In addition, OPNc transcript levels were associated with poor prognostic features, such as central nervous system infiltration, white blood cell counting and the high-risk group at diagnosis. In response to OPNc silencing in B-ALL cell lines, we found increased proliferation rates, as opposed to decreased cell adhesion properties over matrigel matrix. Our data evidenced that overexpressed OPNc in B-ALL with KMT2A-AFF1 is correlated to poor prognostic features and may modulate the leukemic phenotype by the decrease of cell proliferation while promoting cell adhesion. Further work should be conducted in order to evaluate OPNc putative application as an additional risk-stratification and prognostic marker for B-ALL and how OPNc could control leukemia development and progression.

Note: This abstract was not presented at the meeting.

Citation Format: Ana Clara Santos da Fonseca Bastos, Júlio César Santoro, Caroline Barbieri Blunck, Luciana Bueno Ferreira, Maria do Soccro Pombo-de-Oliveira, Mariana Emerenciano, Etel R. Gimba. Osteopontin-c is overexpressed and mediates cell adhesion and proliferation in leukemia cell line with KMT2A-AFF1 [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 3121.

OPNa Overexpression Is Associated with Matrix Calcification in Thyroid Cancer Cell Lines

Osteopontin (OPN) spliced variants (OPN-SV: OPNa, OPNb, and OPNc) are aberrantly expressed in tumors and frequently associated with cancer progression. This holds true for papillary thyroid carcinoma (PTC), which is the most common type of thyroid cancer (TC). PTC often presents with desmoplasia and dystrophic calcification, including psammoma bodies (PB). This work aimed to investigate total OPN (tOPN) and OPN-SV expression and their association with the presence of PB in the PTC classical variants (cPTC), as well as the involvement of OPN-SV in matrix calcification of TC cell lines. We found that cPTC samples presenting PB showed higher OPN expression levels. In TC cell lines, OPNa overexpression promotes higher matrix calcification and collagen synthesis when compared to that of clones overexpressing OPNb or OPNc. In response to OPN knockdown, calcification was inhibited, paralleled with the downregulation of calcification markers. In conclusion, our data evidenced that OPN expression is associated with the presence of PB in cPTC samples. Among the OPN-SV, OPNa is the main contributor to matrix calcification in tested TC cells, providing clues to a better understanding on the biology and ethiopathogenesis of the calcification process in TC cells.

Abstract 1491: Expression of osteopontin splicing isoforms in childhood B-cell precursor acute lymphoblastic leukemia

Osteopontin (OPN) suffers alternative splicing generating three OPN splicing isoforms (OPN-SI), named OPNa, OPNb and OPNc. However, OPN-SI roles in hematological malignancies (HMs) are still under investigation. Detection of specific gene rearrangements allows the identification of relevant prognostic subgroups of childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Patients harbouring the ETV6-RUNX1 rearrangement are classified as a good prognostic subgroup, while those with the KMT2A-AFF1 fusion are included into poor prognostic subgroup. This work aimed to analyze the expression levels of OPN-SI in BCP-ALL cell lines and patient samples. We tested 4 BCP-ALL cell lines: 207, ALL-PO, RS4;11 and REH. Patient samples included 28 samples from patients harbouring the ETV6-RUNX1 fusion and 26 samples presenting the KMT2A-AFF1 rearrangement. We found that these three OPN-SIs are expressed in all BCP-ALL cell lines and in 70% of both patient prognostic subgroups tested. Both 207 and REH cell lines displayed higher OPNc and OPNb levels than OPNa. We found that OPNc is expressed in higher levels than OPNb and OPNa in unfavorable prognostic subgroup and is also overexpressed in relation to OPNc levels in relation to the ETV6-RUNX1 fusion the comparative subgroup. Interestingly, we found that higher OPNc transcriptional levels are associated with poor prognostic features, such as central nervous system (CNS), initial white blood cell counting and high risk of relapse. In conclusion, we found that the three tested OPN-SI are expressed in most tested BCP-ALL cell lines and BCP-ALL human samples. Since higher OPNc levels are associated to prognostic features, our data provide early evidence that these OPN-SIs could specifically contribute to step BCP-ALL progression. Further work should investigate their putative applications as additional risk-stratification and prognostic markers for BCP-ALL, as well as, their roles on modulating HM progression.

Citation Format: Ana Clara Santos da Fonseca Bastos, Caroline Barbieri Blunck Blunck, Luciana Bueno Ferreira, Maria do Socorro Pombo-de-Oliveira, Mariana Emerenciano, Etel R. Gimba. Expression of osteopontin splicing isoforms in childhood B-cell precursor acute lymphoblastic leukemia [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 1491.

Abstract 180: OPNa variant expression is associated with matrix mineralization in thyroid cancer cell lines

Osteopontin (OPN) and its three spliced variants (OPN-SV: OPNa, OPNb and OPNc) are overexpressed in several tumors and frequently associated with cancer progression. This holds true for papillary thyroid carcinoma (PTC), which is the most common variety of thyroid cancer (TC), being the histologic type which often presents desmoplasia (collagen deposition) and dystrophic calcification, including a fairly typical feature, the psammoma bodies (PB). This study aims to investigate the OPN-SV expression in classical variant of PTC (cPTC) and the role of OPN in calcification and collagen deposition into the extracellular matrix of thyroid cancer cell lines. Total OPN and OPN-SV expression was analyzed by immunohistochemistry and real time PCR in a series of 48 cPTC cases and three diffuse sclerosing PTCs. The association of OPN expression and the presence of PB as well as between PB in cPTC and the clinicopathological features of the tumors were evaluated. TPC-1 and c643 TC cell lines overexpressing OPN-SV were tested for the ability to promote calcification and to synthesize collagen in vitro. We also evaluated the expression of calcification markers, including osteocalcin and collagen I. Overexpression of OPNa transcripts was significantly associated with the presence of PB in cPTC samples. The presence of PB in cPTC was associated with younger patients and lymph node metastasis. Moreover, OPNa overexpression displayed a strong capacity to promote calcification and substantial collagen deposition in thyroid cancer cell lines. Upon OPN knockdown, the mRNA expression levels of calcification markers (osteocalcin and collagen I) were downregulated, further evidencing the involvement of OPN on activating these processes. Our data suggest that OPNa plays a role in the extracellular matrix calcification associated with cPTC. Basic research on the interactions between OPNa overexpression by tumor cells and the surrounding microenvironment can give clues for a better understanding of cPTC biology and phenotype.

Citation Format: Luciana B. Ferreira, Raquel T. Lima, Ana Clara Santos da Fonseca Bastos, Andreia Machado Silva, Catarina Tavares, Ana Pestana, Elisabete Rios, Catarina Eloy, Manuel Sobrinho-Simões, Etel Rodrigues Pereira Gimba, Paula Soares. OPNa variant expression is associated with matrix mineralization in thyroid cancer cell lines [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 180.