The tumor microenvironment significantly influences breast cancer development, progression, and metastasis. Various immune cell populations, including T cells, B cells, NK cells, and myeloid cells ...exhibit diverse functions in different breast cancer subtypes, contributing to both anti-tumor and pro-tumor activities.
This review provides an overview of the predominant immune cell populations in breast cancer subtypes, elucidating their suppressive and prognostic effects. We aim to outline the role of the immune microenvironment from normal breast tissue to invasive cancer and distant metastasis.
A comprehensive literature review was conducted to analyze the involvement of immune cells throughout breast cancer progression.
In breast cancer, tumors exhibit increased immune cell infiltration compared to normal tissue. Variations exist across subtypes, with higher levels observed in triple-negative and HER2+ tumors are linked to better survival. In contrast, ER+ tumors display lower immune infiltration, associated with poorer outcomes. Furthermore, metastatic sites commonly exhibit a more immunosuppressive microenvironment.
Understanding the complex interaction between tumor and immune cells during breast cancer progression is essential for future research and the development of immune-based strategies. This comprehensive understanding may pave the way for more effective treatment approaches and improved patients outcomes.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
To prevent replication fork collapse and genome instability under replicative stress, DNA damage tolerance (DDT) mechanisms have evolved. The RAD5 homologs, HLTF (helicase-like transcription factor) ...and SHPRH (SNF2, histone-linker, PHD and RING finger domain-containing helicase), both ubiquitin ligases, are involved in several DDT mechanisms; DNA translesion synthesis (TLS), fork reversal/remodeling and template switch (TS). Here we show that these two human RAD5 homologs contain functional APIM PCNA interacting motifs. Our results show that both the role of HLTF in TLS in HLTF overexpressing cells, and nuclear localization of SHPRH, are dependent on interaction of HLTF and SHPRH with PCNA. Additionally, we detected multiple changes in the mutation spectra when APIM in overexpressed HLTF or SHPRH were mutated compared to overexpressed wild type proteins. In plasmids from cells overexpressing the APIM mutant version of HLTF, we observed a decrease in C to T transitions, the most common mutation caused by UV irradiation, and an increase in mutations on the transcribed strand. These results strongly suggest that direct binding of HLTF and SHPRH to PCNA is vital for their function in DDT.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Proliferating cell nuclear antigen (PCNA) is a cellular hub in DNA metabolism and a potential drug target. Its binding partners carry a short linear motif (SLiM) known as the PCNA-interacting ...protein-box (PIP-box), but sequence-divergent motifs have been reported to bind to the same binding pocket. To investigate how PCNA accommodates motif diversity, we assembled a set of 77 experimentally confirmed PCNA-binding proteins and analyzed features underlying their binding affinity. Combining NMR spectroscopy, affinity measurements and computational analyses, we corroborate that most PCNA-binding motifs reside in intrinsically disordered regions, that structure preformation is unrelated to affinity, and that the sequence-patterns that encode binding affinity extend substantially beyond the boundaries of the PIP-box. Our systematic multidisciplinary approach expands current views on PCNA interactions and reveals that the PIP-box affinity can be modulated over four orders of magnitude by positive charges in the flanking regions. Including the flanking regions as part of the motif is expected to have broad implications, particularly for interpretation of disease-causing mutations and drug-design, targeting DNA-replication and -repair.
Full text
Available for:
EMUNI, FZAB, GEOZS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
New antibacterial drugs with novel modes of action are urgently needed as antibiotic resistance in bacteria is increasing and spreading throughout the world. In this study, we aimed to explore the ...possibility of using APIM-peptides targeting the bacterial β-clamp for treatment of skin infections. We selected a lead peptide, named betatide, from five APIM-peptide candidates based on their antibacterial and antimutagenic activities in both G
and G
bacteria. Betatide was further tested in minimal inhibitory concentration (MIC) assays in ESKAPE pathogens, in
infection models, and in a resistance development assay. We found that betatide is a broad-range antibacterial which obliterated extracellular bacterial growth of methicillin-resistant
(MRSE) in cell co-cultures without affecting the epithelialization of HaCaT keratinocytes. Betatide also reduced the number of intracellular
in infected HaCaT cells. Furthermore, long-time exposure to betatide at sub-MICs induced minimal or no increase in resistance development compared to ciprofloxacin and gentamicin or ampicillin in
and
. These properties support the potential of betatide for the treatment of topical skin infections.
The DNA damage inducible SOS response in bacteria serves to increase survival of the species at the cost of mutagenesis. The SOS response first initiates error-free repair followed by error-prone ...repair. Here, we have employed a multi-omics approach to elucidate the temporal coordination of the SOS response.
was grown in batch cultivation in bioreactors to ensure highly controlled conditions, and a low dose of the antibiotic ciprofloxacin was used to activate the SOS response while avoiding extensive cell death. Our results show that expression of genes involved in error-free and error-prone repair were both induced shortly after DNA damage, thus, challenging the established perception that the expression of error-prone repair genes is delayed. By combining transcriptomics and a sub-proteomics approach termed signalomics, we found that the temporal segregation of error-free and error-prone repair is primarily regulated after transcription, supporting the current literature. Furthermore, the heterology index (i.e., the binding affinity of LexA to the SOS box) was correlated to the maximum increase in gene expression and not to the time of induction of SOS genes. Finally, quantification of metabolites revealed increasing pyrimidine pools as a late feature of the SOS response. Our results elucidate how the SOS response is coordinated, showing a rapid transcriptional response and temporal regulation of mutagenesis on the protein and metabolite levels.
Base excision repair (BER) initiated by alkyladenine DNA glycosylase (AAG) is essential for removal of aberrantly methylated DNA bases. Genome instability and accumulation of aberrant bases accompany ...multiple diseases, including cancer and neurological disorders. While BER is well studied on naked DNA, it remains unclear how BER efficiently operates on chromatin. Here, we show that AAG binds to chromatin and forms complex with RNA polymerase (pol) II. This occurs through direct interaction with Elongator and results in transcriptional co-regulation. Importantly, at co-regulated genes, aberrantly methylated bases accumulate towards the 3'end in regions enriched for BER enzymes AAG and APE1, Elongator and active RNA pol II. Active transcription and functional Elongator are further crucial to ensure efficient BER, by promoting AAG and APE1 chromatin recruitment. Our findings provide insights into genome stability maintenance in actively transcribing chromatin and reveal roles of aberrantly methylated bases in regulation of gene expression.
Multiple myeloma is a hematological cancer that is considered incurable despite advances in treatment strategy during the last decade. Therapies targeting single pathways are unlikely to succeed due ...to the heterogeneous nature of the malignancy. Proliferating cell nuclear antigen (PCNA) is a multifunctional protein essential for DNA replication and repair that is often overexpressed in cancer cells. Many proteins involved in the cellular stress response interact with PCNA through the five amino acid sequence AlkB homologue 2 PCNA-interacting motif (APIM). Thus inhibiting PCNA's protein interactions may be a good strategy to target multiple pathways simultaneously. We initially found that overexpression of peptides containing the APIM sequence increases the sensitivity of cancer cells to contemporary therapeutics. Here we have designed a cell-penetrating APIM-containing peptide, ATX-101, that targets PCNA and show that it has anti-myeloma activity. We found that ATX-101 induced apoptosis in multiple myeloma cell lines and primary cancer cells, while bone marrow stromal cells and primary healthy lymphocytes were much less sensitive. ATX-101-induced apoptosis was caspase-dependent and cell cycle phase-independent. ATX-101 also increased multiple myeloma cells' sensitivity against melphalan, a DNA damaging agent commonly used for treatment of multiple myeloma. In a xenograft mouse model, ATX-101 was well tolerated and increased the anti-tumor activity of melphalan. Therefore, targeting PCNA by ATX-101 may be a novel strategy in multiple myeloma treatment.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Cell-penetrating peptides (CPPs) are increasingly used for cellular drug delivery in both pro- and eukaryotic cells, and oligoarginines have attracted special attention. How arginine-rich CPPs ...translocate across the cell envelope, particularly for prokaryotes, is still unknown. Arginine-rich CPPs efficiently deliver antimicrobial peptide nucleic acid (PNA) to its intracellular mRNA target in bacteria. We show that resistance to PNA conjugated to an arginine-rich CPP in Escherichia coli requires multiple genetic modifications and is specific for the CPP part and not to the PNA part. An integral part of the resistance was the constitutively activated Cpx-envelope stress response system (cpx∗), which decreased the cytoplasmic membrane potential. This indicates an indirect energy-dependent uptake mechanism for antimicrobials conjugated to arginine-rich CPPs. In agreement, cpx∗ mutants showed low-level resistance to aminoglycosides and an arginine-rich CPP conjugated to a peptide targeting the DNA sliding clamp, i.e., similar uptake in E. coli for these antimicrobial compounds.
Display omitted
We show that activation of the Cpx inner membrane stress response results in decreased respiration and thus a decreased ΔΨ across the inner membrane in Escherichia coli. This results in decreased killing by peptide nucleic acid/APIM when conjugated to arginine-rich cell-penetrating peptides and to aminoglycosides.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Antimicrobial resistance is an increasing threat to global health and challenges the way we treat infections. Peptides containing the PCNA interacting motif APIM (APIM-peptides) were recently shown ...to bind to the bacterial PCNA homolog, the beta (β)-clamp, and to have both antibacterial and anti-mutagenic activities. In this study we explore the antibacterial effects of these peptides on
, a bacterial species commonly found in prosthetic joint infections (PJI). Drug-resistant bacterial isolates from PJIs often lead to difficult-to-treat chronic infections. We show that APIM-peptides have a rapid bactericidal effect which when used at sublethal levels also increase the efficacy of gentamicin. In addition, APIM-peptides reduce development and eliminate already existing
biofilm. To study the potential use of APIM-peptides to prevent PJI, we used an
bone graft model in rats where APIM-peptide, gentamicin, or a combination of the two was added to cement. The bone grafts containing cement with the combination was more effective than cement containing only gentamicin, which is the current standard of care. In summary, these results suggest that APIM-peptides can be a promising new drug candidate for anti-infective implant materials to use in the fight against resistant bacteria and chronic PJI.
Proliferating cell nuclear antigen (PCNA) is an essential protein for DNA replication, DNA repair, cell cycle regulation, chromatin remodeling, and epigenetics. Many proteins interact with PCNA ...through the PCNA interacting peptide (PIP)-box or the newly identified AlkB homolog 2 PCNA interacting motif (APIM). The xeroderma pigmentosum group A (XPA) protein, with a central but somewhat elusive role in nucleotide excision repair (NER), contains the APIM sequence suggesting an interaction with PCNA. With an in vivo based approach, using modern techniques in live human cells, we show that APIM in XPA is a functional PCNA interacting motif and that efficient NER of UV lesions is dependent on an intact APIM sequence in XPA. We show that XPA(-/-) cells complemented with XPA containing a mutated APIM sequence have increased UV sensitivity, reduced repair of cyclobutane pyrimidine dimers and (6-4) photoproducts, and are consequently more arrested in S phase as compared to XPA(-/-) cells complemented with wild type XPA. Notably, XPA colocalizes with PCNA in replication foci and is loaded on newly synthesized DNA in undamaged cells. In addition, the TFIIH subunit XPD, as well as XPF are loaded on DNA together with XPA, and XPC and XPG colocalize with PCNA in replication foci. Altogether, our results suggest a presence of the NER complex in the vicinity of the replisome and a novel role of NER in post-replicative repair.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
PDF
