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Complement activation in tumor microenvironment after neoadjuvant therapy and its impact on pancreatic cancer outcomes
Neoadjuvant therapy (NAT) is increasingly being used for pancreatic ductal adenocarcinoma (PDAC). This study investigates how NAT differentially impacts PDAC’s carcinoma cells and the tumor microenvironment (TME). Spatial transcriptomics was used to compare gene expression profiles in carcinoma cells and the TME of 23 NAT-treated versus 13 NAT-naïve PDACs. Findings were validated by single-nucleus RNA sequencing (snRNA-seq) analysis. NAT induces apoptosis and inhibits proliferation of carcinoma cells and coordinately upregulates multiple complement genes (C1R, C1S, C3, C4B and C7) within the TME. Higher TME complement expression following NAT is associated with increased immunomodulatory and neurotrophic cancer-associated fibroblasts (CAFs); more CD4+ T cells; reduced immune exhaustion gene expression, and improved overall survival. snRNA-seq analysis demonstrates C3 complement is mainly upregulated in CAFs. These findings suggest that local complement dynamics could serve as a novel biomarker for prognosis, evaluating treatment response, and guiding therapeutic strategies in NAT-treated PDAC patients.
Catalytic dwell oscillations complete the F1-ATPase mechanism
The F1-ATPase molecular motor rotates subunit-γ in 120° power strokes within its ring of three catalytic sites separated by catalytic dwells for ATP hydrolysis and Pi release. By monitoring rotary position of subunit-γ in E. coli F1 every 5 μs, we resolved Stage-1 catalytic dwell oscillations that extend from -13° to 13° centered at 0° consistent with F1 structures containing transition state inhibitors, which decay by a first order process consistent with ATP hydrolysis. During Stage-2, 80% of the oscillations extend from 3° and 25° centered at 14°, while 20% are centered at 33° and can extend to 27°–44° comparable to the ATP binding position. Remarkably, in Stage-3 subunit-γ returns to 0° to end the catalytic dwell, which keeps the start of power strokes in phase for consecutive rotational events. These newly observed states fit with F1 structures that were inconsistent with the canonical mechanism, and indicate that catalytic dwell oscillations must persist until the correct occupancy of substrates and products occurs at all three catalytic sites. When that condition is met, F1 can proceed to the next power stroke. Understanding the basis of these catalytic dwell oscillations completes the F1-ATPase rotary mechanism.
Accelerated differentiation of neo-W nuclear-encoded mitochondrial genes between two climate-associated bird lineages signals potential co-evolution with mitogenomes
There is considerable evidence for mitochondrial-nuclear co-adaptation as a key evolutionary driver. Hypotheses regarding the roles of sex-linkage have emphasized Z-linked nuclear genes with mitochondrial function (N-mt genes), whereas it remains contentious whether the perfect co-inheritance of W genes with mitogenomes could hinder or facilitate co-adaptation. Young (neo-) sex chromosomes that possess relatively many N-mt genes compared to older chromosomes provide unprecedented hypothesis-testing opportunities. Eastern Yellow Robin (EYR) lineages in coastal and inland habitats with different climates are diverged in mitogenomes, and in a ~ 15.4 Mb nuclear region enriched with N-mt genes, in contrast with otherwise-similar nuclear genomes. This nuclear region maps to passerine chromosome 1A, previously found to be neo-sex in the inland EYR genome. To compare sex-linked Chr1A-derived genes between lineages, we assembled and annotated the coastal EYR genome. We found that: (i) the coastal lineage shares a similar neo-sex system with the inland lineage, (ii) neo-W and neo-Z N-mt genes are not more diverged between lineages than are comparable non-N-mt genes, and showed little evidence for broad positive selection, (iii) however, W-linked N-mt genes are more diverged between lineages than are their Z-linked gametologs. The latter effect was ~7 times stronger for N-mt than non-N-mt genes, suggesting that W-linked N-mt genes might have diverged between lineages under environmental selection through co-evolution with mitogenomes. Finally, we identify a candidate gene driver for divergent selection, NDUFA12. Our data represent a rare example suggesting a possible role for W-associated mitochondrial-nuclear interactions in climate-associated adaptation and lineage differentiation.
Targeting of TAMs: can we be more clever than cancer cells?
With increasing incidence and geography, cancer is one of the leading causes of death, reduced quality of life and disability worldwide. Principal progress in the development of new anticancer therapies, in improving the efficiency of immunotherapeutic tools, and in the personification of conventional therapies needs to consider cancer-specific and patient-specific programming of innate immunity. Intratumoral TAMs and their precursors, resident macrophages and monocytes, are principal regulators of tumor progression and therapy resistance. Our review summarizes the accumulated evidence for the subpopulations of TAMs and their increasing number of biomarkers, indicating their predictive value for the clinical parameters of carcinogenesis and therapy resistance, with a focus on solid cancers of non-infectious etiology. We present the state-of-the-art knowledge about the tumor-supporting functions of TAMs at all stages of tumor progression and highlight biomarkers, recently identified by single-cell and spatial analytical methods, that discriminate between tumor-promoting and tumor-inhibiting TAMs, where both subtypes express a combination of prototype M1 and M2 genes. Our review focuses on novel mechanisms involved in the crosstalk among epigenetic, signaling, transcriptional and metabolic pathways in TAMs. Particular attention has been given to the recently identified link between cancer cell metabolism and the epigenetic programming of TAMs by histone lactylation, which can be responsible for the unlimited protumoral programming of TAMs. Finally, we explain how TAMs interfere with currently used anticancer therapeutics and summarize the most advanced data from clinical trials, which we divide into four categories: inhibition of TAM survival and differentiation, inhibition of monocyte/TAM recruitment into tumors, functional reprogramming of TAMs, and genetic enhancement of macrophages.
A multifunctional mesoporous silica drug delivery nanosystem that ameliorates tumor hypoxia and increases radiotherapy efficacy
Radiotherapy (RT) is a widely used treatment with strong therapeutic effects, but overcoming challenges related to hypoxia-induced tumor resistance and ineffective antitumor immune responses is crucial for optimal outcomes. In this study, we developed a versatile nanosystem using mesoporous silica nanoparticles (MSNs), R837, and a small quantity of manganese peroxide (Mn/ZnO2). The synthesized MSN@R837-Mn/ZnO2 nanoparticles exhibited precise tumor targeting and accumulation, controlled drug release under acidic conditions, and increased sensitivity in magnetic resonance imaging. These attributes collectively augmented the therapeutic efficacy of RT by alleviating hypoxia and immunosuppression. Tumor cells treated with RT combined with these nanoparticles displayed reduced oxidative stress, alleviated hypoxia, and normalized blood vessel formation. Notably, all mice in the RT + PD-1 + MSN@R837-Mn/ZnO2 group achieved complete tumor regression with extended survival. Safety assessments confirmed the absence of MSN@R837-Mn/ZnO2 toxicity, highlighting its potential as a promising approach with dual functionality for the diagnostic imaging and treatment of cancer.
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