Basal-like breast cancer represents a subgroup of mammary cancers associated with a particularly poor prognosis, as they are refractory to current targeted therapies employed for the treatment of breast cancer. In this work I aimed to explore the therapeutic potential of selective estrogen receptor modulators (SERMs), a targeted breast cancer treatment, in combination with epigallocatechin gallate (EGCG), for the treatment of basal-like breast cancer, using MDA-MB-231 cell as an in vitro model of the disease. A significant reduction in MDA-MB-231 cell number and a significant increase in cytotoxicity was observed following treatment with 25 [mu]M of EGCG in combination with 1 [mu]M of 4-hydroxytamoxifen (4-OHT) (EGCG+4-OHT) or 4 [mu]M of raloxifene (EGCG+Ral) over a 36 h time course. However, these effects were not resolved in time, with an increase in G₁-phase cell cycle arrest. Changes in the metabolism of EGCG were dismissed as a possible mechanism through which the combination treatments may be eliciting the cytotoxicity. Changes in the expression and phosphorylation of various signaling proteins, important for the proliferation and survival of basal-like breast cancer, were investigated through Western blotting. Interestingly, the two combination treatments produced very similar results; reductions in the phosphorylation of EGFR and AKT occurred after 6, 12, and 18 h with EGCG+4-OHT and 6, 12, 18 and 24 h with EGCG+Ral, while a reduction in S6K phosphorylation was observed following 6, 12, 18 and 24 h of both combination treatments. Interestingly, both SERMs contributed significantly to the net reduction in S6K phosphorylation, induced by the combination treatments. Both combination treatments were also associated with a significant increase in the phosphorylation and total expression of stress activated protein kinases, p38 and JNK1/2 following 12, 18 and 24 h of treatment. As changes were observed at an intracellular signaling level, the effect of the combination treatments were investigated at the transcriptomic level after 18 h of treatment, using human oligonucleotide microarrays. This transcriptomic analysis revealed that both combination treatments reduced the transcript expression of five enzymes involved with cholesterol synthesis, which was confirmed through qRT-PCR. Cholesterol is an important component of the plasma membrane and is critical for the transduction of extracellular signals. Furthermore, both combination treatments induced the transcriptomic expression of the zinc coordinating metallothionein (MT) proteins. This was associated with an increased nuclear localization of MTF-1, the transcription factor responsible for MT expression, after 6, 12 and 18 h of both combination treatments. Finally, nuclear Western blotting of the NF-[kappa]B subunit, p65, revealed that both combination treatments reduced the nuclear localization of NF-[kappa]B following 6, 12 and 18 h. In collating this data, it appears that the combination treatments of EGCG+4-OHT and EGCG+Ral are inducing cytotoxicity through various mechanisms, including reduced cellular signaling through EGFR, AKT and S6K, increased stress signaling through JNK1/2 and p38 and altered gene expression of MTs and enzymes involved with cholesterol synthesis. Therefore, the combination treatment of EGCG+SERMs exhibits therapeutic potential in MDA-MB-231 cells, a model of basal-like breast cancer.

<p>The human skin provides us with an excellent protective barrier and possesses a remarkable ability of constant renewal. Basal cell carcinoma is the most common type of skin cancer. The aim of this project was to verify results from an earlier study investigating the molecular differences between basal cell carcinoma (BCC) and basal cells of normal human epidermis. In that study microdissection of cell populations from BCC and basal cells of normal epidermis respectively was performed in five cases of confirmed BCC. Following RNA extraction and amplification, a gene expression analysis was performed using a 46 k human cDNA microarray. Comparison of expression profiles showed a differential expression of approximately 300 genes in BCC. An upregulation of signaling pathways previously known to be of importance in BCC development could be observed, as well as a downregulation of differentiation markers, MHC class II molecules, and proteins active in scavenging of oxygen radicals. We wanted to confirm these findings for a number of selected genes, using real time PCR. The focal point of this project was microdissection of cells from BCC and subsequent isolation of RNA. Microdissection based methods offer a possibility of selecting well defined cell populations for further analysis by using a focused laser beam. Initially tests in order to optimize the method were also performed, concerning the dehydration process and choice of slides used in microdissection. Isolation of RNA may, as we experienced, be associated with problems due to destruction of RNA by degrading enzymes.</p>

Diss. (sammanfattning) Göteborg : Göteborgs universitet, 2009. / Härtill 4 uppsatser.

Diss. (sammanfattning) Göteborg : Göteborgs universitet, 2008. / Härtill 4 uppsatser.

Thesis (Ph.D.) - University of Queensland, 2005. / Includes bibliography.

Το σηματοδοτικό μονοπάτι Hippo παίζει καθοριστικό ρόλο στην ομοιόσταση ιστών και οργάνων κατά την εμβρυογένεση και την ενήλικο ζωή ενώ όλο και περισσότερες μελέτες αναδεικνύουν τη σημασία του στην καρκινογένεση. Σκοπός της παρούσας μελέτης ήταν η διερεύνηση της έκφρασης των πρωτεϊνών YAP, TAZ, Ε-cadherin και b-catenin, στο Βασικοκυτταρικό καρκίνωμα του δέρματος (ΒΚΚ) και η συσχέτιση των ευρημάτων με την ενεργοποίηση της σηματοδοτικής οδού HIPPO, με την αλληλεπίδραση των σηματοδοτικών μονοπατιών Wnt/b-catenin και Hippo/YAP και με κλινικοπαθολογοανατομικές παραμέτρους του νεοπλάσματος. . Μέθοδοι και αποτελέσματα: Με την τεχνική της ανοσοϊστοχημείας ελεγχθηκε η έκφραση των πρωτεϊνών ΥΑΡ, ΤΑΖ, Ε-cadherin και b-catenin σε τομές παραφίνης μονιμομοποιημένου σε φορμόλη ιστού 95 περιστατικών ανθρώπινου ΒΚΚ. Η έκφραση και των δύο βασικών επιτελεστικών μορίων του Hippo (YAP,TAZ) βρέθηκε αυξημένη στον πυρήνα όλων των ιστολογικών τύπων ΒΚΚ και ήταν σημαντικά αυξημένη στους υψηλού κινδύνου υπότυπους. Τα μικροοζώδη, διαφοροποιούνταν τόσο από τα διηθητικά όσο και από τους χαμηλού κινδύνου υπότυπους εμφανίζοντας ενδιάμεση έκφραση για την ΥΑΡ όμως την υψηλότερη έκφραση για την ΤΑΖ μεταξύ όλων των ιστολογικών υποτύπων. Η E-cadherin στα περιστατικά μας διατηρούσε σε μεγάλο βαθμό τη μεμβρανική της έκφραση αν και μειωμένη σε σχέση με τη φυσιολογική επιδερμίδα, χωρίς σημαντικές διαφορές μεταξύ των ιστολογικών τύπων ή μεταξύ του όγκου συνολικά και της διηθητικής παρυφής. Τέλος, στα μισά περίπου περιστατικά μας διαπιστώθηκε πυρηνική έκφραση της β-catenin η οποία ήταν σημαντική στα διηθητικά σε σχέση με τα οζώδη, ενώ επίσης τα διηθητικά ΒΚΚ εμφάνιζαν τα υψηλότερα ποσοστά κυτταροπλασματικής έκφρασης της β-catenin μεταξύ όλων των ιστολογικών τύπων. Επίσης, η μεμβρανική έκφραση της β-catenin στο διηθητικό μέτωπο των υψηλού κινδύνου υποτύπων ήταν μειωμένη σε σχέση με τους χαμηλού κινδύνου. Συμπεράσματα: Το μονοπάτι Hippo φαίνεται ότι συμβάλλει στην παθογένεια του ΒΚΚ με έμφαση στους υψηλού κινδύνου υποτύπους, έχοντας κατά κύριο λόγο ογκογόνο δράση. Στην περίπτωση του ΒΚΚ, η Ε-cadherin δεν φαίνεται να αποτελεί ανωφερή ρυθμιστή του Hippo καθώς η διατήρηση της μεμβρανικής της έκφρασης δεν συνοδεύεται από σημαντικές αλλαγές στην υποκυτταρική εντόπιση της ΥΑΡ, γεγονός που ίσως αντανακλά τον ιστό προέλευσης του όγκου και οι νεοπλασματικές φωλεές διατηρούν αξιοσημείωτη κυτταρική συνοχή και επιθηλιακό φαινότυπο ακόμη και στην περίπτωση των επιθετικών υποτύπων. Η προφανής απαίτηση για Wnt/β-catenin σηματοδότηση στα ΒΚΚ θα πρέπει να ερευνηθεί περαιτέρω καθώς ενδέχεται να βρίσκεται υπό αρνητική ρύθμιση από παράγοντες όπως η ενεργοποίηση της non canonical Wnt σηματοδοτικής οδού που δρά ανταγωνιστικά ως προς την canonical Wnt σηματοδοτική οδό και η έκφραση σε υψηλά επίπεδα της E-cadherin στις μεμβράνες. Η παρατηρούμενη βιβλιογραφική ετερογένεια ως προς τη σημασία της Wnt σηματοδότησης στην παθογένεια του ΒΚΚ πιθανόν να αντανακλά βιολογική ετερογένεια ως προς την απαίτηση για Wnt σηματοδότηση εν γένει στο ΒΚΚ που πιθανόν αντικατοπτρίζει διαφορετική συμβολή της Wnt σηματοδοτικής οδού στα διάφορα στάδια εξέλιξης του όγκου ή/και στους διαφορετικούς ιστολογικούς υπότυπους. / Hippo pathway has emerged as a crucial component of organ and tissue homeostasis. Increasing number of studies highlight it’s significance in carcinogenesis. The aim of this study was to determine the expression of YAP, TAZ, Ε-cadherin and b-catenin in human Basal Cell Carcinoma (BCC) and correlate it with the activation status of Hippo signaling pathway, the interaction of Wnt/b-catenin και Hippo/YAP signaling pathways and clinicopathological features of the tumor. Materials and results: Paraffin-embedded tissue sections from 95 human BCC cases were processed by immunohistochemistry for the expression of YAP, TAZ, Ε-cadherin and b-catenin. Nuclear expression of both Hippo effector proteins (YAP,TAZ) was observed in 100% of cases and was strongly corellated with the high risk subtypes. Micronodular differed from both the invasive and low risk subtypes by showing intermediate nuclear YAP expression and the highest nuclear TAZ expression among all BCC subtypes tested. E-cadherin expression in our cases was largely membranous, though reduced compared to normal epidermis, with no significant differences between histologic subtypes or between the tumor overall and it’s invasive front. Finaly, nuclear β-catenin expression was observed in about half of our cases and was significantly increased in the infiltrative compared to the nodular subtype with the infiltrative BCC’s having the highest cytoplasmic β-catenin expression among all subtypes tested. Moreover, membranous β-catenin expression at the invasive front was significantly reduced in the high risk subtypes when compared to the low risk. Conclusions: We believe that Hippo signaling pathway holds a critical oncogenic role in the pathogenesis of BCC, expecially in the high risk subtypes. In the case of BCC, Ε-cadherin doesn’t appear to act as an upstream regulator of Hippo because it’s relatively stable membranous expression doesn’t seem to follow any variations in the subcellular localization of YAP, an observation probably reflecting the fact that skin is the tissue of origin for BCC. Neoplastic nests remain remarkably cohesive and retain an epithelial phenotype even in the high risk variants. The obvious demand for Wnt/β-catenin signaling in BCC development needs to be further invastigated because it seems likely being under negative regulation by factors like activation of the non canonical Wnt signaling cascade and increased expression levels of membranous E-cadherin. The observed variability in the literature regarding the significance of canonical Wnt signaling in BCC pathogenesis could be reflecting biological variability in the contribution of Wnt signaling in BCC pathogenesis overall, corresponding to differencies in Wnt signaling between the various stages of neoplastic development or/and the different histologic subtypes .

Basal cell carcinoma is an indolent, slow-growing tumor that rarely metastasizes. Approximately 70% of tumors occur in the head and neck regions. If a basal cell tumor metastasizes, it usually spreads to the regional lymph nodes first, followed by the lungs. We describe a patient with basal cell carcinoma of the right lower extremity with skin metastases. Skin biopsy of one tumor revealed fibroepithelioma of Pinkus, a rare variant of basal cell carcinoma.

We report two cases of combined cutaneous tumors composed of melanoma and carcinoma. The first tumor presented as a 5-mm pink-blue macule over the right zygomatic arch in an 85-year-old man. Shave biopsy and immunohistochemical studies revealed that the tumor was composed of melanoma (highlighted by SOX10 and MART-1, with high Ki-67 proliferative index) intermixed with nodular basal cell carcinoma (highlighted by pan-cytokeratin and Ber-EP4). The neoplastic melanocytes were confined to the basal cell carcinoma nodules, and a diagnosis of combined melanoma in situ and basal cell carcinoma was rendered. After therapeutic excision, the patient was disease-free at 9 months after the initial diagnosis. The second tumor presented as a 6-mm pink-brown crusted papule on the right forehead in an 89-year-old man. Shave biopsy and immunohistochemical studies revealed that the tumor was composed of malignant melanoma (MM) (highlighted by S100 and MART-1) intermixed with squamous cell carcinoma (SCC) (highlighted by cytokeratin and p63), and a diagnosis of combined MM-SCC was rendered. These two cases highlight the importance of recognizing these rare types of melanocytic-epithelial cutaneous neoplasms to arrive at an accurate diagnosis that may inform appropriate disease stage and therapy.

Background. Both basal-like subtype and BRCA1-related breast cancers tend to have a poor overall prognosis and lack of effective treatments. Given that the lung cancer drug gefitinib and the leukemia drug dasatinib inhibit proteins also belonging to the molecular signature of this subtype, we and others hypothesized that they might be useful therapies for those two breast cancer subgroups. / Methods. Eight breast cancer cell lines were characterized by immunohistochemistry and western blotting and were treated with both drugs. Response was measured by using the sulphorhodamine B (SRB) assay. / Results. Two out of six basal-like cell lines were sensitive to gefitinib and five of six to dasatinib. BRCA1-related breast cancers were also responsive to dasatinib (three out of four). Moreover, EGFR and caveolin-1 act as markers for dasatinib sensitivity, but do not appear to be the primary targets of this drug. The presence of SRC but not ABL is necessary to achieve a response to dasatinib. / Conclusion. Dasatinib is more effective in the treatment of basal-like breast cancers than gefitinib and acts by inhibiting SRC and other molecules that are yet to be determined.

No description available.