Molecular Oncology最新文献

Although first-line alectinib has prolonged survival in ALK-mutated non-small-cell lung cancers (NSCLCs), the response to treatment varies among patients, and the primary/early development of alectinib resistance mechanisms is still not fully understood. Here, we analyzed molecular profiles of 108 alectinib-treated patients (first-line and second-line after crizotinib) with confirmed relapse by targeted sequencing of cancer-related genes. After first-line treatment, off-target MET and NF2 alterations were more frequent than on-target alterations within the first 6 months, causing primary or early resistance. Conversely, on-target alterations became prevalent after 1 year of first-line alectinib treatment and predominantly after second-line. The incidence of acquired resistance also depended on EML4-ALK variants. In variant 1 (v1), off-target alterations were responsible for 50% of resistance cases after first-line alectinib therapy, whereas on-target mutations had no contribution in this subgroup. In variant 3 (v3), on-target alterations resulted in 46% of resistance cases, whereas only 18% were caused by off-target mutations. After second-line treatment, the most common mutations in v1 were L1196M (42%) and G1269A (25%), while G1202R was detected in 45% of v3 tumors. These findings emphasize the importance of stratifying resistance mechanisms to guide tailored treatment for ALK-positive NSCLCs.

Epigenetic regulators, such as the SWI/SNF complex, with important roles in tissue development and homeostasis, are frequently mutated in cancer. ARID1A, a subunit of the SWI/SNF complex, is mutated in approximately 20% of all bladder tumors; however, the consequences of this remain poorly understood. Finding truncations to be the most common mutation, we generated loss- and gain-of-function models to conduct RNA-Seq, interactome analyses, Omni-ATAC-Seq, and functional studies to characterize ARID1A-affected pathways potentially suitable for the treatment of ARID1A-deficient bladder cancers. We observed decreased cell proliferation and deregulation of stress-regulated pathways, including DNA repair, in ARID1A-deficient cells. Furthermore, ARID1A was linked to alternative splicing and translational regulation on RNA and interactome levels. ARID1A deficiency drastically reduced the accessibility of chromatin, especially around introns and distal enhancers, in a functional enrichment analysis. Less accessible chromatin areas were mapped to pathways such as cell proliferation and DNA damage response. Indeed, the G2/M checkpoint appeared impaired after DNA damage in ARID1A-deficient cells. Together, our data highlight the broad impact of ARID1A loss and the possibility of targeting proliferative and DNA repair pathways for treatment.

Triple-negative breast cancer (TNBC) is highly metastatic and presents clinical challenges given the lack of targeted therapies. Here, we report that the ShcD phosphotyrosine adaptor protein is upregulated in TNBC, and its expression correlates with overall reduced patient survival and decreased response to chemotherapy. In human breast cancer cells, we demonstrate that ShcD expression promotes cell invasion and reduces adhesion, and that these effects are abrogated by mutating the ShcD phosphotyrosine binding (PTB) domain. Similarly, in a three-dimensional assembloid model, ShcD-expressing spheroids derived from brain metastatic TNBC cells show enhanced infiltration into cerebral organoids. Using a proteomic screen for ShcD binding partners, we identify multiple components of epidermal growth factor receptor (EGFR) signaling and confirm these interactions with ShcD but not the PTB mutant. Interestingly, the ShcD interactome correlates with EGFR tyrosine kinase inhibitor resistance, in line with our findings that ShcD overexpression results in hyperphosphorylation of EGFR while ShcD knockout or PTB mutation reverts this response. Lastly, pharmacological inhibition of the ShcD PTB domain using indomethacin in TNBC cells decreases EGFR binding and hyperphosphorylation and reduces cell invasion. Altogether, our results identify ShcD as a potential contributor to metastasis in TNBC, and they provide a molecular basis for clinical targeting of adaptor proteins.

Circulating tumor cells (CTCs) play an important role in metastasis formation. Aberrant signaling of oncogenic pathways (e.g., PI3K/AKT/mTOR pathway) drives tumor progression. In this work, the susceptibility of the colon cancer CTC-derived cell line CTC-MCC-41 to AKT and mammalian target of rapamycin (mTOR) inhibitors was evaluated. Additionally, the functional role of the expressed AKT isoforms was characterized in this cell line. The efficacy of the AKT inhibitor MK2206, the mTOR inhibitor RAD001, and the combination was examined in CTC-MCC-41 cells in a murine intracardiac xenotransplantation model. Furthermore, stable isoform-specific AKT1 or AKT2 knockdowns (KDs) as well as AKT1/AKT2 double-KD cells were generated. Differentially regulated proteins and phospho-peptides were identified using liquid chromatography coupled mass spectrometry (LC-MS). CTC-MCC-41 cells showed a high susceptibility for dual targeting of AKT and mTOR in vivo, indicating that selective eradication of CTCs by AKT/mTOR inhibitors may be considered a new treatment option in cancer. KD of AKT1 or AKT2 significantly reduced the proliferation of CTC-MCC-41 cells. AKT KDs share commonly regulated proteins and phospho-proteins, but also regulate a large number uniquely. AKT1/AKT2 double-KD cells show a strongly dysregulated replication machinery, as well as a decrease in cell cycle activity and stem-cell-associated processes, underlining the non-redundant role of AKT isoforms.

Identifying targets involved in tumor evolution and immune escape is an active area of research in oncology. Macrophage migration inhibitory factor (MIF) is an upstream immunoregulatory cytokine that promotes transformed cell proliferation and survival, and generates a tumor-permissive immune landscape of immunosuppressive myeloid and T cells. Shvefel and colleagues have identified a key role for MIF in tumor progression in melanoma clones with low tumor heterogeneity. These findings provide important insights into the potential therapeutic utility of MIF antagonists and support ongoing research to utilize MIF pathway inhibitors for improved therapeutic outcomes.

B-cell chronic lymphocytic leukemia (B-CLL) is characterized by highly heterogeneous genomic alterations and altered signaling pathways, with limited studies on its proteome. Our study presents a comprehensive analysis of the proteome and phosphoproteome in B-CLL and CLL-like monoclonal B-cell lymphocytosis (MBL) primary cells. Using high-resolution mass spectrometry, we identified 2970 proteins and 316 phosphoproteins across five tumor samples, including 55 newly identified phosphopeptides (ProteomeXchange-PXD005997). Our multifaceted approach also integrated protein microarrays and western blotting for further data validation in a new patient cohort of 14 patients. Despite sharing 73% of their proteomes, the phosphoproteomes varied significantly among samples, independent of cytogenetic alterations and immunoglobulin heavy variable cluster (IGHV) mutational status. We identified common functional hallmarks in B-CLL and MBL phosphoproteomes, notably tonic signaling (low-level, constitutive signaling) of the B-cell antigen-specific receptor (BCR) and nuclear factor NF-kappa-B (NF-kβ)/signal transducer and activator of transcription 3 (STAT3) pathways. Nine phosphoproteins involved in BCR signaling were further validated, showing a high correlation with early disease stages. Our study advances the field by providing a detailed perspective on the proteome and phosphoproteome of B-CLL cells, revealing signaling pathways crucial for disease development and progression. Integrating diverse proteomics techniques and identifying novel phosphopeptides offers new insights into CLL biology, potentially informing future therapeutic strategies and biomarker development for early diagnosis and personalized treatment.

Cancer's notorious heterogeneity poses significant challenges, as each tumor comprises a unique ecosystem. While single-cell and spatial transcriptomics advancements have transformed our understanding of spatial diversity within tumors, the temporal dimension remains underexplored. Tumors are dynamic entities that continuously evolve and adapt, and relying solely on static snapshots obscures the intricate interplay between cancer cells and their microenvironment. Here, we advocate for integrating temporal dynamics into cancer research, emphasizing a fundamental shift from traditional endpoint experiments to data-driven, continuous approaches. This integration involves, for instance, the development of advanced live imaging techniques, innovative temporal omics methodologies, and novel computational tools.

Solid tumours routinely access the blood supply by promoting endothelium-dependent angiogenesis; but tumour vasculature can also be formed by cancer cells themselves via vasculogenic mimicry (VM). Investigation of the gene expression profile during the early stages of VM formation by MDA-MB-231-LM2 breast cancer cells identified the transcriptional regulator inhibitor of DNA binding 1 (ID1) to be elevated ~ 10-fold within the first 2 hours. This role for ID1 in promoting VM was supported by ID1 genetic knockdown or chemical inhibition interrupting VM formation by MDA-MB-231-LM2 (breast) and BxPC-3 (pancreatic) cancer cells. More specifically, reducing ID1 lowered cancer cell expression of endothelial cell genes (e.g. CDH5, TIE2) and production of pro-angiogenic proteins (e.g. VEGF, CD31, MMP9 and IL-8). In silico analysis of MDA-MB-231 cells engrafted into mice identified elevated ID1 expression in cancer cells that had metastasised to the lungs or liver, and an enrichment of pro-angiogenic genes. Additionally, Id1 knockdown in 4T1.13 murine breast cancer cells demonstrated reduced tumour growth and metastasis in vivo. Taken together, this study further implicates ID1 in a vascular program within cancer cells that supports disease progression.

The brain is a common site of metastatic dissemination in advanced melanoma. Due to limited access to samples from human brain metastases, our understanding of the tumor microenvironment in the brain lags behind that of other sites, and murine studies are therefore highly informative. Rodriguez-Baena et al. conducted elegant studies of myeloid cells within melanoma brain metastases, demonstrating their plasticity and changes before and after colonization by melanoma cells. The immune-inhibitory changes in microglial cells may be reversed or mitigated by inhibition of RelA/NF-κB.

Retinoids have demonstrated efficacy as preventative/treatment agents for keratinocyte carcinomas (KCs): basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (SCC). However, retinoid resistance mechanisms limit the efficacy of these compounds. A subset of KCs expresses Preferentially Expressed Antigen in Melanoma (PRAME): a retinoid signaling corepressor. PRAME is proposed to repress retinoid signaling by guiding enhancer of zeste homolog 2 (EZH2) to retinoic acid response elements (RARE) in promoters. We investigated the effects of PRAME on KC pathogenesis and retinoid response. High-PRAME expression in tumors was negatively correlated with epidermal differentiation gene signatures. PRAME overexpression downregulated epidermal differentiation gene signatures and impaired differentiation in 3D culture. PRAME overexpression attenuated retinoid-induced RARE activation, growth suppression, and differentiation responses. Conversely, low-PRAME tumors and PRAME-depleted KC cells demonstrated enriched epidermal differentiation gene signatures. PRAME downregulation restored retinoid-induced RARE activation, growth suppression, keratinization in SCC, and cell death signaling in BCC. Furthermore, combined retinoid and EZH2 inhibitor treatment augmented RARE activation and suppressed PRAME-expressing KC cell growth. Hence, PRAME confers retinoid resistance in KC, which may be overcome by EZH2 inhibition.