Biomedical subjects

Damir Krunic

Publications and source records attributed to Damir Krunic.

4 recordsLinked to original sources

PubMed2025

Expression of Bovine Meat and Milk Factor in Hepatocellular Carcinoma and Colorectal Liver Metastasis Patients.

Bovine meat and milk factors (BMMFs) are plasmid-like DNA molecules isolated from cow's milk, meat, and human cancer tissues proposed to contribute to the development of specific types of cancer including colorectal cancer (CRC) and breast cancer based on chronic inflammation-associated indirect carcinogenesis. Chronic necro-inflammation of the liver poses a strong risk factor for the induction of hepatocellular carcinoma (HCC), which is associated with high intake of meat. Whether BMMFs contribute to HCC carcinogenesis or the development of colorectal liver metastasis (CRLM) remains unknown. Therefore, in this study, the presence of BMMFs was assessed in the liver of patients with viral and nonviral hepatitis-related HCC (n = 25), CRLM (14) and in healthy liver tissue from autopsy specimens (18) using monoclonal antibodies against the conserved BMMF Rep protein for immunohistochemistry, immunofluorescence detection, and immunoblotting. Rep was expressed in all tumor-distant and peritumor tissue specimens of HCC and CRLM patients and associated with CD68+ macrophages around portal triads. The number of Rep+CD68+cells was increased in HCC and CRLM patients compared to healthy liver tissue, which may indicate a link between BMMFs and tumor-associated chronic inflammation in the liver. Exclusively in viral hepatitis-linked HCC, Rep expression was also detected in the tumor. In addition, specifically in the liver of healthy individuals, we observed a well-defined gradient Rep expression in hepatocytes around the central veins. Altogether, these observations may indicate that the presence of BMMFs in the liver is associated with chronic inflammation and may represent a novel risk factor or surrogate marker for liver cancer.

Humans↗

PubMed2023

Bovine meat and milk factor protein expression in tumor-free mucosa of colorectal cancer patients coincides with macrophages and might interfere with patient survival.

Bovine milk and meat factors (BMMFs) are plasmid-like DNA molecules isolated from bovine milk and serum, as well as the peritumor of colorectal cancer (CRC) patients. BMMFs have been proposed as zoonotic infectious agents and drivers of indirect carcinogenesis of CRC, inducing chronic tissue inflammation, radical formation and increased levels of DNA damage. Data on expression of BMMFs in large clinical cohorts to test an association with co-markers and clinical parameters were not previously available and were therefore assessed in this study. Tissue sections with paired tumor-adjacent mucosa and tumor tissues of CRC patients [individual cohorts and tissue microarrays (TMAs) (n = 246)], low-/high-grade dysplasia (LGD/HGD) and mucosa of healthy donors were used for immunohistochemical quantification of the expression of BMMF replication protein (Rep) and CD68/CD163 (macrophages) by co-immunofluorescence microscopy and immunohistochemical scoring (TMA). Rep was expressed in the tumor-adjacent mucosa of 99% of CRC patients (TMA), was histologically associated with CD68+/CD163+ macrophages and was increased in CRC patients when compared to healthy controls. Tumor tissues showed only low stromal Rep expression. Rep was expressed in LGD and less in HGD but was strongly expressed in LGD/HGD-adjacent tissues. Albeit not reaching statistical significance, incidence curves for CRC-specific death were increased for higher Rep expression (TMA), with high tumor-adjacent Rep expression being linked to the highest incidence of death. BMMF Rep expression might represent a marker and early risk factor for CRC. The correlation between Rep and CD68 expression supports a previous hypothesis that BMMF-specific inflammatory regulations, including macrophages, are involved in the pathogenesis of CRC.

Humans↗

PubMed2005

Telomere-dependent chromosomal instability.

Telomeres are specialized DNA-protein structures at the ends of the linear chromosomes. In mammalian cells, they are composed of multifold hexameric TTAGGG repeats and a number of associated proteins. The double-stranded telomeric DNA ends in a 3' single stranded overhang of 150 to 300 base pair (bp) which is believed to be required for a higher order structure (reviewed in (Blackburn, 2001)). One important model is that the telomeres form loop structures, the T-loops, and by invasion of the 3' overhang into the duplex region of the double stranded part protect the DNA against degradation and hinder the cellular machinery to recognize the ends as broken DNA, thus providing chromosomal integrity (Griffith et al, 1999). If telomeres become critically short they loose their capping function, become sticky, and are prone to illegitimate chromosome end-to-end fusions. The resulting dicentric chromosomes are highly unusable and because of bridge-fusion-breakage cycles they give rise to chromosomal translocations, deletions, and amplifications. Thus, critically short telomeres are thought to be responsible for the onset of genomic instability. In addition, we provide evidence that in a length-independent manner telomeres can confer to genomic instability by forming telomericaggregates which through chromosomal dys-locations contribute to chromosomal aberrations.

Animals↗

PubMed2004

Cell cycle-dependent 3D distribution of telomeres and telomere repeat-binding factor 2 (TRF2) in HaCaT and HaCaT-myc cells.

Telomeres are specialized structures at the ends of the chromosomes that, with the help of proteins--such as the telomere repeat-binding factor TRF2 -, form protective caps which are essential for chromosomal integrity. Investigating the structure and three-dimensional (3D) distribution of the telomeres and TRF2 in the nucleus, we now show that the telomeres of the immortal HaCaT keratinocytes are distributed in distinct non-overlapping territories within the inner third of the nuclear space in interphase cells, while they extend more widely during mitosis. TRF2 is present at the telomeres at all cell cycle phases. During mitosis additional TRF2 protein concentrates all around the chromosomes. This change in staining pattern correlates with a significant increase in TRF2 protein at the S/G2 transition as seen in Western blots of synchronized cells and is paralleled by a cell cycle-dependent regulation of TRF2 mRNA, arguing for a specific role of TRF2 during mitosis. The distinct territorial localization of telomeres is abrogated in a HaCaT variant that constitutively expresses c-Myc--a protein known to contribute to genomic instability. These cells are characterized by overlapping telomere territories, telomeric aggregates (TAs), that are accompanied by an overall irregular telomere distribution and a reduced level in TRF2 protein. These TAs which are readily detectable in interphase nuclei, are similarly present in mitotic cells, including cells in telophase. Thus, we propose that TAs, which subsequently also cluster their respective chromosomes, contribute to genomic instability by forcing an abnormal chromosome segregation during mitosis.

Cell Cycle↗