Osteopontin Expression in Thyroid Cancer: Deciphering EMT-Related Molecular Mechanisms.

Thyroid cancer is the most common tumor arising from the endocrine system and generally presents good prognosis. However, its aggressive subtypes are related to therapeutic resistance and early metastasis. Epithelial-mesenchymal transition (EMT) and its reverse process, the mesenchymal-epithelial transition (MET), are key events mediating cancer progression, including in thyroid cancer. The matricellular protein osteopontin (OPN) has been reported as a master regulator of EMT in many tumor types. Although high OPN expression has been described and associated with important aspects of thyroid cancer progression, there is no clear evidence regarding OPN as a regulator of EMT in thyroid cancer. Thus, taking together the known roles of OPN in the modulation of EMT in cancer and the information reporting the expression of OPN in thyroid tumor progression, this review aims at summarizing and discussing data related to EMT in thyroid cancer and its putative relation to the roles of OPN in the development of thyroid cancer. These data provide new insights into the molecular mechanisms by which OPN could potentially modulate EMT in thyroid tumors, generating evidence for future studies that may contribute to new therapeutic, prognostic and/or diagnostic tools.

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.

Osteopontin-4 and Osteopontin-5 splice variants are expressed in several tumor cell lines.

Among osteopontin splice variants (OPN-SV), the expression profile of osteopontin-4 (OPN4) and osteopontin-5 (OPN5) has not been addressed in distinct cancer types. We herein aimed to investigate their expression in several cancer cell lines, besides comparing it in relation to the three previously described OPN-SV: OPNa, OPNb and OPNc. Total RNA from cancer cell lines, including prostate (PC3 and DU145), ovarian (A2780), breast (MCF-7 and MDA-MB-231), colorectal (Caco-2, HT-29 and HCT-116), thyroid (TT, TPC1 and 8505c) and lung (A549 and NCI-H460) was extracted, followed by cDNA synthesis. OPN-SV transcript analysis by RT-PCR or RT-qPCR were performed using OPN-SV specific oligonucleotides and gapdh and actin transcripts were used as housekeeping controls. OPN4 and OPN5 transcripts displayed co-expression in most tested cell lines. OPN4 was found expressed in similar or higher levels in relation to OPN5. Moreover, in most tested cell lines, OPN4 is also expressed in similar levels to OPNa or OPNb. The expression of OPN5 is also generally variable in relation to the other OPN-SV, but expressed in similar or higher levels in relation to OPNc, depending on each tested cell line. OPN4 and OPN5 seem to be co-expressed in several tumor types and OPN4 is one of the most overexpressed OPN-SV in distinct tumor cell lines. Once both OPN4 and OPN5 are differentially expressed and also evidence tumor-specific expression patterns, we hypothesize that similarly to the other OPN-SV, they also possibly contribute to key aspects of tumor progression, what should be further functionally investigated in distinct tumor models.