The Spectrum of HPV-independent Penile Intraepithelial Neoplasia: A Proposal for Subclassification.

Compared with vulva, precursor lesions of human papillomavirus (HPV)-independent invasive squamous cell carcinoma (SCC) of the penis are insufficiently characterized. We analyzed the histologic and immunohistochemical characteristics of 70 peritumoral precursor lesions and correlated them with the histology and mutational profile of the adjacent HPV-negative invasive penile SCC. Atypical basal keratinocyte proliferation with variously elongated epithelial rete with premature squamatiziation, but regular superficial cornification, termed differentiated penile intraepithelial neoplasia (d-PeIN), were identified adjacent to 42/70 (60%) SCC (36/42 keratinizing ( P <0.001); 3 papillary, and 1 each verrucous, clear cell, sarcomatoid SCC). d-PeIN were associated with chronic inflammatory dermatoses (32/42; P <0.001), p53 overexpression (26/42; P <0.001), and hotspot mutations in TP53 (32/42; P <0.001), CDKN2A (26/42; P <0.001) or both (21/42; P =0.003) in the adjacent SCC. Cytoplasmic p16 ink4a overexpression in 5/42 d-PeIN correlated with CDKN2A missense mutations in the adjacent SCC. In all, 21/70 (30%) cornified verrucous or glycogenated verruciform precursors with minimal atypia and wild-type p53 (18/21; P <0.001) occurred adjacent to verrucous or papillary SCC (17/21; P <0.001) and keratinizing (4/21) SCC, which harbored mutations in HRAS and/or PIK3CA (12/21; P <0.004). Undifferentiated p16 ink4a -negative full-thickness precursors were identified in 7/70 (10%) SCC. Four histologically different HPV-independent penile precursor lesions can be assigned to 2 major genetic/biological pathways with characteristic highly differentiated precursors requiring different clinical management decisions. These include d-PeIN in chronic inflammatory dermatoses, with p53 overexpression and TP53/CDKN2A mutations, and the p53 wild-type verrucous and verruciform precursors unassociated with dermatoses, but with mutations in oncogenes PIK3CA and HRAS .

Different Mutational Landscapes in Human Papillomavirus-Induced and Human Papillomavirus-Independent Invasive Penile Squamous Cell Cancers.

Penile squamous cell carcinomas (SCC) are rare cancers that arise after transforming human papillomavirus (HPV) infections or independent of HPV in the background of chronic dermatoses. Limited knowledge about genetic alterations driving penile carcinogenesis comes from studies of mainly small cohorts of typically mixed etiology. In this comparative genetic study of HPV-induced and HPV-independent invasive penile SCC of 156 patients from a single institution in a low-incidence country, hotspots of 50 cancer-relevant genes were analyzed with targeted next-generation sequencing. Seventy-nine of 156 SCC were classified as HPV induced, and 77 of 156 SCC arose independent of HPV. Only 28 (35%) of 79 HPV-induced penile SCC, but 69 (90%) of 77 HPV-independent SCC carried somatic gene mutations. PIK3CA, FGFR3, and FBXW7 mutations occurred in both groups in similar numbers as seen in other human cancers. In contrast, mutations in TP53 (44/77; 57%), CDKN2A (35/77; 45%), and HRAS (13/77; 17%) genes occurred with one exception of a HIV positive patient exclusively in HPV-independent SCC with a frequent co-occurrence of TP53 and CDKN2A mutations (28/77; 42%). Mutations in multiple genes occurred in 9 (11%) of 79 HPV-induced SCC versus 47 (62%) of 77 HPV-independent SCC (χ2; P < .001). More than one mutation per gene (multi hits) was characteristic for HPV-independent SCC in 14 (18%) of 77 compared with only 3 (4%) of 79 HPV-induced SCC (χ2; P < .001). The total number of mutations in HPV-induced penile SCC (47 mutations) was significantly lower than that in HPV-independent SCC (143 mutations; Welsh test; P < .001). The presence of somatic driver gene mutations did not correlate with the age of patients, histology, or tumor stage of the primary SCC in either etiologic group, suggesting that acquisition of driver gene mutations is an early event after invasion. This large cohort analysis identified characteristic differences in mutational landscapes for the 2 etiologies. While genetic mutations in tumor suppressor genes drive HPV-independent penile carcinogenesis, oncogenic action of E6 and E7 substitute for mutations in HPV-induced SCC. A subgroup of patients with advanced SCC may be candidates for targeted therapy and clinical trials, although the majority of advanced penile SCC remain a therapeutic challenge.

"Pulsed Hypoxia" Gradually Reprograms Breast Cancer Fibroblasts into Pro-Tumorigenic Cells via Mesenchymal-Epithelial Transition.

Hypoxia arises in most growing solid tumors and can lead to pleotropic effects that potentially increase tumor aggressiveness and resistance to therapy through regulation of the expression of genes associated with the epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET). The main goal of the current work was to obtain and investigate the intermediate phenotype of tumor cells undergoing the hypoxia-dependent transition from fibroblast to epithelial morphology. Primary breast cancer fibroblasts BrC4f, being cancer-associated fibroblasts, were subjected to one or two rounds of "pulsed hypoxia" (PH). PH induced transformation of fibroblast-shaped cells to semi-epithelial cells. Western blot analysis, fluorescent microscopy and flow cytometry of transformed cells demonstrated the decrease in the mesenchymal markers vimentin and N-cad and an increase in the epithelial marker E-cad. These cells kept mesenchymal markers αSMA and S100A4 and high ALDH activity. Real-time PCR data of the cells after one (BrC4f_Hyp1) and two (BrC4f_Hyp2) rounds of PH showed consistent up-regulation of TWIST1 gene as an early response and ZEB1/2 and SLUG transcriptional activity as a subsequent response. Reversion of BrC4f_Hyp2 cells to normoxia conditions converted them to epithelial-like cells (BrC4e) with decreased expression of EMT genes and up-regulation of MET-related OVOL2 and c-MYC genes. Transplantation of BrC4f and BrC4f_Hyp2 cells into SCID mice showed the acceleration of tumor growth up to 61.6% for BrC4f_Hyp2 cells. To summarize, rounds of PH imitate the MET process of tumorigenesis in which cancer-associated fibroblasts pass through intermediate stages and become more aggressive epithelial-like tumor cells.

EGFR Transgene Stimulates Spontaneous Formation of MCF7 Breast Cancer Cells Spheroids with Partly Loss of HER3 Receptor.

Multicellular spheroids with 3D cell-cell interactions are a useful model to simulate the growth conditions of cancer. There is evidence that in tumor spheroids, the expression of various essential molecules is changed compared to the adherent form of cell cultures. These changes include growth factor receptors and ABC transporters and result in the enhanced invasiveness of the cells and drug resistance. It is known that breast adenocarcinoma MCF7 cells can spontaneously form 3D spheroids and such spheroids are characterized by high expression of EGFR/HER2, while the natural phenotype of MCF7 cells is EGFRlow/HER2low. Therefore, it was interesting to reveal if high epidermal growth factor receptor (EGFR) expression is sufficient for the conversion of adherent MCF7 to spheroids. In this study, an MCF7 cell line with high expression of EGFR was engineered using the retroviral transduction method. These MCF7-EGFR cells assembled in spheroids very quickly and grew predominantly as a 3D suspension culture with no special plates, scaffolds, growth supplements, or exogenous matrixes. These spheroids were characterized by a rounded shape with a well-defined external border and 100 µM median diameter. The sphere-forming ability of MCF7-EGFR cells was up to 5 times stronger than in MCF7wt cells. Thus, high EGFR expression was the initiation factor of conversion of adherent MCF7wt cells to spheroids. MCF7-EGFR spheroids were enriched by the cells with a cancer stem cell (CSC) phenotype CD24-/low/CD44- in comparison with parental MCF7wt cells and MCF7-EGFR adhesive cells. We suppose that these properties of MCF7-EGFR spheroids originate from the typical features of parental MCF7 cells. We showed the decreasing of HER3 receptors in MCF7-EGFR spheroids compared to that in MCFwt and in adherent MCF7-EGFR cells, and the same decrease was observed in the MCF7wt spheroids growing under the growth factors stimulation. To summarize, the expression of EGFR transgene in MCF7 cells stimulates rapid spheroids formation; these spheroids are enriched by CSC-like CD24-/CD44- cells, they partly lose HER3 receptors, and are characterized by a lower potency in drug resistance pomp activation compared to MCF7wt. These MCF7-EGFR spheroids are a useful cancer model for the development of anticancer drugs, including EGFR-targeted therapeutics.

Establishment of primary human breast cancer cell lines using "pulsed hypoxia" method and development of metastatic tumor model in immunodeficient mice.

BACKGROUND: Among breast cancer (BC) patients the outcomes of anticancer therapy vary dramatically due to the highly heterogeneous molecular characteristics of BC. Therefore, an extended panel of BC cell lines are required for in vitro and in vivo studies to find out new characteristic of carcinogenesis and metastasis. The purpose of this study was to develop patient-derived BC cell cultures and metastatic tumor models representing a tool for personal therapy and translational research. METHODS: Breast cancer cells were prepared by optimizing technique from tumor samples. We used real-time RT-PCR, flow cytometry, western blotting, cytotoxicity assay, karyotyping and fluorescent and electron microscopy analyses to characterize the established cell lines. BC xenografts in scid mice were used for in vivo tumorigenicity studies. RESULTS: The technique of preparing primary cells was optimized and this resulted in a high output of viable and active proliferated cells of nine patient-derived breast cancer cell lines and one breast non-malignant cell line. High E-cadherine and EpCAM expression correlated positively with epithelial phenotype while high expression of N-cadherine and Vimentin were shown in cells with mesenchymal phenotype. All mesenchymal-like cell lines were high HER3-positive-up to 90%. More interesting than that, is that two cell lines under specific culturing conditions (pulsed hypoxia and conditioned media) progressively transformed from mesenchymal to epithelial phenotypes displaying the expression of respective molecular markers proving that the mesenchymal-to-epithelial transition occurred. Becoming epithelial, these cells have lost HER3 and decreased HER2 membrane receptors. Three of the established epithelial cancer cell lines were tumorigenic in SCID mice and the generated tumors exhibited lobules-like structures. Ultrastructure analysis revealed low-differentiate phenotype of tumorigenic cell lines. These cells were in near-triploid range with multiple chromosome rearrangements. Tumorigenic BrCCh4e cells, originated from the patient of four-course chemotherapy, initiated metastasis when they were grafted subcutaneous with colonization of mediastinum lymph nodes. CONCLUSIONS: The developed BC cells metastasizing to mediastinum lymph nodes are a relevant model for downstream applications. Moreover, our findings demonstrate that pulsed hypoxia induces transformation of primary fibroblastoid breast cancer cells to epithelial-like cells and both of these cultures-induced and original-don't show tumor initiating capacity.