Quantitative evidence for early metastatic seeding in colorectal cancer

Bacterial ghosts: A breakthrough approach to cancer vaccination

Cancer is a devastating disease worldwide with high mortality rates and is a foremost concern for society. Immunotherapy has emerged as a promising strategy for treating cancer, harnessing the power of immune system to recognize and kill tumor cells. Bacterial ghosts (BGs), a novel platform in cancer vaccination, are suitable for personalized and effective immunotherapeutic interventions. BG are empty bacterial cell envelopes generated through a controlled lysis process, leaving behind empty but structurally intact cell membranes. BGs have been used as vaccine adjuvants and vaccine delivery vehicles worldwide. They possess inherent immunogenicity, enabling them to be used for controlled release and targeted drug delivery. Recently, the potential of BGs has been explored for tumor inhibition, making them suitable carrier vehicles. This review highlights cancer immunotherapy, methods of BG preparation, characterization of BGs, the interaction of BGs with the immune system, and research progress on BG-based cancer vaccines with future insights.

Polyclonal-to-monoclonal transition in colorectal precancerous evolution

Unravelling the origin and evolution of precancerous lesions is crucial for effectively preventing malignant transformation, yet our current knowledge remains limited1-3. Here we used a base editor-enabled DNA barcoding system4 to comprehensively map single-cell phylogenies in mouse models of intestinal tumorigenesis induced by inflammation or loss of the Apc gene. Through quantitative analysis of high-resolution phylogenies including 260,922 single cells from normal, inflamed and neoplastic intestinal tissues, we identified tens of independent cell lineages undergoing parallel clonal expansions within each lesion. We also found polyclonal origins of human sporadic colorectal polyps through bulk whole-exome sequencing and single-gland whole-genome sequencing. Genomic and clinical data support a model of polyclonal-to-monoclonal transition, with monoclonal lesions representing a more advanced stage. Single-cell RNA sequencing revealed extensive intercellular interactions in early polyclonal lesions, but there was significant loss of interactions during monoclonal transition. Therefore, our data suggest that colorectal precancer is often founded by many different lineages and highlight their cooperative interactions in the earliest stages of cancer formation. These findings provide insights into opportunities for earlier intervention in colorectal cancer.

Tissue-colonizing disseminated tumor cells secrete prostaglandin E2 to promote NK cell dysfunction and evade anti-metastatic immunity

Natural killer (NK) cells are critical for anti-metastatic immunity and can eliminate metastasizing tumor cells within circulation and sites of metastatic seeding. Here, we show that disseminated tumor cells (DTCs) colonizing the mouse lung secrete prostaglandin E2 (PGE2) to locally induce NK cell dysfunction, allowing outgrowing metastases to escape immune control and establish metastatic disease. Mechanistically, PGE2 signaling through its receptors EP2 and EP4 mediates NK cell dysfunction, which leads to reprogramming of NK cell gene expression and results in impaired production of anti-metastatic cytokines. In human cancer patients, the PGE2-EP2/EP4 axis is associated with NK cell dysfunction within distant organ metastases. Disabling EP2/EP4 signaling in NK cells prevents their dysfunction in DTC-colonized lungs and achieves effective NK cell-mediated control of metastatic disease. Our findings reveal a suppressive signaling axis exploited by metastasizing tumor cells to escape immune control in distant organs that could be targeted for metastatic cancer therapy.

Prevention of liver metastasis via the pharmacological suppression of AMIGO2 expression in tumor cells

AMIGO2 adheres to liver endothelium and induces liver metastasis. We revealed that genetically altering AMIGO2 expression in tumor cells affects their liver metastatic potential, depending on the AMIGO2 expression level. The aim of this study was to prevent liver metastasis by pharmacologically suppressing AMIGO2 expression. For screening, we used the mouse LV12 cells because of their affinity to adhere to liver endothelium and metastasize the liver owing to elevated AMIGO2 expression. Of the 285 compounds tested, 17 reduced AMIGO2 mRNA expression. We subsequently screened for compounds that inhibited tumor cell adhesion to liver endothelium and identified five compounds that inhibit three signaling pathways (MEK, JAK, and JNK). Treatment with these compounds inhibited liver metastasis of LV12 cells. Next, we used clinically available signal inhibitors (MEK inhibitor trametinib, JAK inhibitor ruxolitinib, and JNK inhibitor SP600125), and found that ruxolitinib inhibits AMIGO2 expression more stably. Furthermore, ruxolitinib inhibited the adhesion of LV12 cells to liver endothelium and suppressed liver metastasis. Using the MKN45 gastric cancer cells, we confirmed that ruxolitinib could prevent liver metastasis of human cancer cells. These results demonstrate that pharmacological inhibition of AMIGO2 expression in tumor cells is a promising novel strategy to prevent and control liver metastasis.

Veratridine, a plant-derived alkaloid, suppresses the hyperactive Rictor-mTORC2 pathway: a new targeted therapy for primary and metastatic colorectal cancer

Despite considerable advances to improve colorectal cancer (CRC) survival over the last decade, therapeutic challenges remain due to the rapid metastatic dissemination of primary tumors and screening limitations. Meanwhile, the rise of CRC in younger adults (Early-onset CRC), commonly diagnosed with a metastatic form of the disease, shows the pressing need to develop more effective targeted therapies to decrease the high mortality rates associated with metastatic disease. Hyperactivation of the Rictor-mTORC2-AKT signaling pathway drives key metastatic players in diverse malignant tumors, including early- and late-onset colorectal cancer. Selective mTORC2 inhibitors are becoming a potential treatment strategy for CRC due to the therapeutic limitations of mTORC1 inhibitors. Veratridine (VTD), a lipid-soluble alkaloid extracted from Liliaceae plants, can transcriptionally increase UBXN2A, which induces 26S proteasomal degradation of the Rictor protein, a key member in the mTORC2 complex. Destabilization of Rictor protein by VTD decreases Akt phosphorylation on Ser473, which is responsible for metastatic signaling downstream of the mTORC2 pathway in diverse malignant tumors. VTD decreases the population of metastatic colon cancer stem cells and functions as an angiogenesis inhibitor. VTD effectively reduces the spheroid growth rate and restricts cell migration. Live cell migration and invasion assays alongside biomechanical-force-based experiments revealed that VTD suppresses colon cancer cell invasiveness and the ensuing risk of tumor metastasis. A CRC mouse model that mimics the natural stages of human sporadic CRC revealed that VTD treatment significantly decreases tumor growth in a UBXN2A-dependent manner. This study showed a novel mechanistic connection between a ubiquitin-like protein and mTORC2-dependent migration and invasion in CRC tumors. This study revealed the therapeutic benefit of selective inhibition of Rictor in CRC, particularly in tumors with a hyperactive Rictor-mTORC2 signaling pathway. Finally, this study opened a new platform for repurposing VTD, a supplemental anti-hypertension molecule, into an effective targeted therapy in CRC tumors.

Activation of the WNT7B/β-Catenin Pathway Initiates GLUT1 Expression and Promotes Aerobic Glycolysis in Colorectal Cancer Cells

Glucose is an important energy source for tumors, however the molecular mechanisms by which tumor cells regulate glucose uptake remain unclear. In this study, we aimed to investigate the regulation mechanism of the WNT7B/β-catenin pathway for glucose transporter 1 (GLUT1)-mediated glucose metabolism in colorectal cancer. Here, we found that WNT7B expression levels were significantly increased in colorectal cancer tissues and closely associated with the clinical stage and lymph node metastasis in patients with colorectal cancer. Next, we confirmed that WNT7B significantly increased the glucose consumption and lactic acid levels in SW480 cells by overexpressing WNT7B. Additionally, gene and protein levels of GLUT1 were increased in WNT7B-overexpressing SW480 cells. However, WNT7B knockdown reversed these effects. WNT7B also enhanced GLUT1-mediated cell proliferation, invasion, and migration. WNT7B overexpression inhibited the effect of glucose deprivation on apoptosis. The WNT/β-catenin signaling pathway inhibitor, LGK974, inhibited WNT7B secretion, leading to GLUT1 levels downregulation and promotion of cell apoptosis. Ectopic tumor xenograft model experiments revealed that WNT7B promoted tumor progression in mice. Overall, our results suggest that WNT7B promotes β-catenin entry into the nucleus to initiates GLUT1 transcription, increases glucose transport and consumption, and enhances aerobic glycolysis, thus promoting tumor progression in colorectal cancer cells.

Discovery of prognostic lncRNAs in colorectal cancer using spatial transcriptomics

Colorectal cancer (CRC) exhibits significant genetic and epigenetic diversity, evolving into sub-clonal populations with varied metastatic potentials and treatment responses. Predicting metastatic disease in CRC patients remains challenging, underscoring the need for reliable biomarkers. While most research on therapeutic targets and biomarkers has focused on proteins, non-coding RNAs such as long non-coding RNAs (lncRNAs) comprise most of the transcriptome and demonstrate superior tissue- and cancer-specific expression. We utilised spatial transcriptomics to investigate lncRNAs in CRC tumours, offering more precise cell-type-specific expression data compared to bulk RNA sequencing. Our analysis identified 301 lncRNAs linked to malignant CRC regions, which we validated with public data. Further validation using RNA-FISH revealed three lncRNAs (LINC01978, PLAC4, and LINC01303) that are detectable in stage II tumours but not in normal epithelium and are upregulated in metastatic tissues. These lncRNAs hold potential as biomarkers for early risk assessment of metastatic disease.

Clonal Lineage Tracing with Somatic Delivery of Recordable Barcodes Reveals Migration Histories of Metastatic Prostate Cancer

The patterns by which primary tumors spread to metastatic sites remain poorly understood. Here, we define patterns of metastatic seeding in prostate cancer using a novel injection-based mouse model-EvoCaP (Evolution in Cancer of the Prostate), featuring aggressive metastatic cancer to bone, liver, lungs, and lymph nodes. To define migration histories between primary and metastatic sites, we used our EvoTraceR pipeline to track distinct tumor clones containing recordable barcodes. We detected widespread intratumoral heterogeneity from the primary tumor in metastatic seeding, with few clonal populations instigating most migration. Metastasis-to-metastasis seeding was uncommon, as most cells remained confined within the tissue. Migration patterns in our model were congruent with human prostate cancer seeding topologies. Our findings support the view of metastatic prostate cancer as a systemic disease driven by waves of aggressive clones expanding their niche, infrequently overcoming constraints that otherwise keep them confined in the primary or metastatic site. Significance: Defining the kinetics of prostate cancer metastasis is critical for developing novel therapeutic strategies. This study uses CRISPR/Cas9-based barcoding technology to accurately define tumor clonal patterns and routes of migration in a novel somatically engineered mouse model (EvoCaP) that recapitulates human prostate cancer using an in-house developed analytical pipeline (EvoTraceR).

National Landscape of Neoadjuvant Therapy in Potentially Resectable Colon Cancer

INTRODUCTION

Surgery followed by pathology-guided adjuvant therapy is standard treatment for colon cancer. Data from the FOxTROT clinical trial showed potential benefit of a 6-wk neoadjuvant chemotherapy (NACT) in T3/T4 patients. The present study evaluated real-world outcomes of neoadjuvant therapy in a national cohort of patients with resectable colon cancer.

METHODS

169,120 patients with clinical stage I, II, or III colon cancer from the National Cancer Database registry were included. Patients were categorized as having received neoadjuvant therapy followed by surgery (NACT), surgery then adjuvant chemotherapy (AC), or surgery alone. Factors associated with treatment sequencing and outcomes were assessed.

RESULTS

Of identified patients, 1.4% received NACT including 0.5% of stage I, 1.8% of stage II, and 3.0% of stage III. For stage I, 5-y overall survival (OS) was 74.7% after AC, 62.2% after NACT, and 76.4% after SA. For stage II, 5-y OS was 73.2% after AC, 66.8% after NACT, and 64.3% after SA. For stage III, 5-y OS was 67.3% after AC, 67.7% after NACT, and 42.4% after SA. Cox proportional-hazards model suggested NACT had worse outcomes versus AC in clinical stages I (hazard ratio [HR] = 1.59, 95% confidence interval [CI] 1.39-1.85, P < 0.01) and II (HR = 1.37, 95% CI 1.23-1.52, P < 0.01). In stage III, there was no difference in OS between NACT and AC (HR = 1.1, 95% CI 0.99-1.22, P = 0.05).

CONCLUSIONS

In a real-world national cohort of patients with resectable colon cancer, NACT had no OS benefit over AC. Future studies should examine which subset of patients might benefit from neoadjuvant approaches.

Tumour evolution and microenvironment interactions in 2D and 3D space

To study the spatial interactions among cancer and non-cancer cells1, we here examined a cohort of 131 tumour sections from 78 cases across 6 cancer types by Visium spatial transcriptomics (ST). This was combined with 48 matched single-nucleus RNA sequencing samples and 22 matched co-detection by indexing (CODEX) samples. To describe tumour structures and habitats, we defined 'tumour microregions' as spatially distinct cancer cell clusters separated by stromal components. They varied in size and density among cancer types, with the largest microregions observed in metastatic samples. We further grouped microregions with shared genetic alterations into 'spatial subclones'. Thirty five tumour sections exhibited subclonal structures. Spatial subclones with distinct copy number variations and mutations displayed differential oncogenic activities. We identified increased metabolic activity at the centre and increased antigen presentation along the leading edges of microregions. We also observed variable T cell infiltrations within microregions and macrophages predominantly residing at tumour boundaries. We reconstructed 3D tumour structures by co-registering 48 serial ST sections from 16 samples, which provided insights into the spatial organization and heterogeneity of tumours. Additionally, using an unsupervised deep-learning algorithm and integrating ST and CODEX data, we identified both immune hot and cold neighbourhoods and enhanced immune exhaustion markers surrounding the 3D subclones. These findings contribute to the understanding of spatial tumour evolution through interactions with the local microenvironment in 2D and 3D space, providing valuable insights into tumour biology.

Defining heritability, plasticity, and transition dynamics of cellular phenotypes in somatic evolution

Single-cell sequencing has characterized cell state heterogeneity across diverse healthy and malignant tissues. However, the plasticity or heritability of these cell states remains largely unknown. To address this, we introduce PATH (phylogenetic analysis of trait heritability), a framework to quantify cell state heritability versus plasticity and infer cell state transition and proliferation dynamics from single-cell lineage tracing data. Applying PATH to a mouse model of pancreatic cancer, we observed heritability at the ends of the epithelial-to-mesenchymal transition spectrum, with higher plasticity at more intermediate states. In primary glioblastoma, we identified bidirectional transitions between stem- and mesenchymal-like cells, which use the astrocyte-like state as an intermediary. Finally, we reconstructed a phylogeny from single-cell whole-genome sequencing in B cell acute lymphoblastic leukemia and delineated the heritability of B cell differentiation states linked with genetic drivers. Altogether, PATH replaces qualitative conceptions of plasticity with quantitative measures, offering a framework to study somatic evolution.

Exploring the diagnostic and prognostic significance of circulating tumor cells in stage II-IV colorectal cancer using a nano-based detection method

BACKGROUND

Colorectal cancer (CRC) is a leading cause of cancer mortality globally, underscoring the urgency for a noninvasive and effective biomarker to enhance patient prognosis. Circulating tumor cells (CTCs), a potential marker for real-time tumor monitoring, are limited in clinical utility due to the low sensitivity of existing detection methods. Previously, we introduced a novel nano-based CTCs detection method that relies on the electrical properties of cell surfaces, thus eliminating the need for specific molecular biomarkers. In this study, we used this technique to evaluate the diagnostic and prognostic value of CTCs in stage II-IV CRC.

METHODS

A total of 194 participants were included, consisting of 136 CRC patients and 58 healthy individuals. The peripheral blood of the participants was collected, and CTC enumeration was performed utilizing the nano-based detection method that we newly developed. The receiver operating characteristic (ROC) curve and multivariate Cox proportional-hazards analysis were used to assess the effectiveness of CTCs for diagnosing CRC and predicting patient prognosis.

RESULTS

The nano-based method demonstrated an ability to differentiate CRC patients from healthy individuals with a sensitivity of 84.6% and a specificity of 94.8%. Furthermore, baseline CTC levels were predictive of progression-free survival (PFS) in CRC patients, with lower levels associated with longer PFS compared to higher levels (4.5 vs 8.0 months at 15 CTCs/mL, p = 0.016; 4.4 vs 8.0 months at 20 CTCs/mL, p = 0.028). We also explored the dynamic changes in the number of CTCs after 1 to 5 cycles of chemotherapy. Patients with increasing CTC levels typically experienced disease progression (PD), while those with decreasing levels often achieved a partial response (PR) or maintained stable disease (SD). These findings suggest that the dynamic fluctuations in CTC counts are closely tied to the clinical course of the disease.

CONCLUSION

Our study indicates the potential of nano-based CTCs detection in diagnosing and predicting outcomes for patients with stage II-IV CRC.

The evolutionary theory of cancer: challenges and potential solutions

The clonal evolution model of cancer was developed in the 1950s-1970s and became central to cancer biology in the twenty-first century, largely through studies of cancer genetics. Although it has proven its worth, its structure has been challenged by observations of phenotypic plasticity, non-genetic forms of inheritance, non-genetic determinants of clone fitness and non-tree-like transmission of genes. There is even confusion about the definition of a clone, which we aim to resolve. The performance and value of the clonal evolution model depends on the empirical extent to which evolutionary processes are involved in cancer, and on its theoretical ability to account for those evolutionary processes. Here, we identify limits in the theoretical performance of the clonal evolution model and provide solutions to overcome those limits. Although we do not claim that clonal evolution can explain everything about cancer, we show how many of the complexities that have been identified in the dynamics of cancer can be integrated into the model to improve our current understanding of cancer.

Genomic biology and therapeutic strategies of liver metastasis from gastric cancer

The liver is a frequent site of metastasis in advanced gastric cancer (GC). Despite significant advancements in diagnostic and therapeutic techniques, the overall survival rate for patients afflicted with gastric cancer liver metastasis (GCLM) remains dismally low. Precision oncology has made significant progress in identifying therapeutic targets and enhancing our understanding of metastasis mechanisms through genome sequencing and molecular characterization. Therefore, it is crucial to have a comprehensive understanding of the various molecular processes involved in GCLM and the fundamental principles of systemic therapy to develop new treatment approaches. This paper aims to review recent findings on the diagnosis, potential biomarkers, and therapies targeting the multiple molecular processes of GCLM, with the goal of improving treatment strategies for patients with GCLM.

A unique interplay of access and selection shapes peritoneal metastasis evolution in colorectal cancer

Whether metastasis in humans can be accomplished by most primary tumor cells or requires the evolution of a specialized trait remains an open question. To evaluate whether metastases are founded by non-random subsets of primary tumor lineages requires extensive, difficult-to-implement sampling. We have realized an unusually dense multi-region sampling scheme in a cohort of 26 colorectal cancer patients with peritoneal metastases, reconstructing the evolutionary history of on average 28.8 tissue samples per patient with a microsatellite-based fingerprinting assay. To assess metastatic randomness, we evaluate inter- and intra-metastatic heterogeneity relative to the primary tumor and find that peritoneal metastases are more heterogeneous than liver metastases but less diverse than locoregional metastases. Metachronous peritoneal metastases exposed to systemic chemotherapy show significantly higher inter-lesion diversity than synchronous, untreated metastases. Projection of peritoneal metastasis origins onto a spatial map of the primary tumor reveals that they often originate at the deep-invading edge, in contrast to liver and lymph node metastases which exhibit no such preference. Furthermore, peritoneal metastases typically do not share a common subclonal origin with distant metastases in more remote organs. Synthesizing these insights into an evolutionary portrait of peritoneal metastases, we conclude that the peritoneal-metastatic process imposes milder selective pressures onto disseminating cancer cells than the liver-metastatic process. Peritoneal metastases' unique evolutionary features have potential implications for staging and treatment.

Inferring cancer type-specific patterns of metastatic spread

The metastatic spread of a cancer can be reconstructed from DNA sequencing of primary and metastatic tumours, but doing so requires solving a challenging combinatorial optimization problem. This problem often has multiple solutions that cannot be distinguished based on current maximum parsimony principles alone. Current algorithms use ad hoc criteria to select among these solutions, and decide, a priori, what patterns of metastatic spread are more likely, which is itself a key question posed by studies of metastasis seeking to use these tools. Here we introduce Metient, a freely available open-source tool which proposes multiple possible hypotheses of metastatic spread in a cohort of patients and rescores these hypotheses using independent data on genetic distance of metastasizing clones and organotropism. Metient is more accurate and is up to 50x faster than current state-of-the-art. Given a cohort of patients, Metient can calibrate its parsimony criteria, thereby identifying shared patterns of metastatic dissemination in the cohort. Reanalyzing metastasis in 169 patients based on 490 tumors, Metient automatically identifies cancer type-specific trends of metastatic dissemination in melanoma, high-risk neuroblastoma and non-small cell lung cancer. Metient's reconstructions usually agree with semi-manual expert analysis, however, in many patients, Metient identifies more plausible migration histories than experts, and further finds that polyclonal seeding of metastases is more common than previously reported. By removing the need for hard constraints on what patterns of metastatic spread are most likely, Metient introduces a way to further our understanding of cancer type-specific metastatic spread.

Survival Analysis, Clinical Characteristics, and Predictors of Cerebral Metastases in Patients with Colorectal Cancer

INTRODUCTION

Colorectal cancer (CRC) is the third most common cancer globally and a leading cause of cancer-related deaths. While liver metastasis is common, brain metastasis (BM) is rare, occurring in 0.1% to 14% of cases. Risk factors for BM include lung metastasis at diagnosis, rectal cancer, and mutations in RAS and KRAS genes. Due to its rarity, guidelines for BM screening and treatment are limited. The aim of this study is to identify the clinical characteristics and predictors of BM at the time of the initial diagnosis of CRC.

METHODS

We evaluated patients ≥18 years old with metastatic colorectal cancer and brain metastases at diagnosis from the SEER database (2010-2021). A retrospective cohort study was conducted to analyze overall survival and predictive factors for brain metastasis, utilizing multivariate logistic regression, Kaplan-Meier survival analysis, and the Cox proportional hazards models, with p-values < 0.05 considered significant.

RESULTS

Out of 24,703 patients with metastatic colorectal cancer (mCRC), 228 (0.92%) had brain metastasis (BM) at diagnosis. BM was more prevalent in average-onset mCRC (≥50 years) compared to early-onset (<50 years) (1% vs. 0.55%, p = 0.004). Certain factors, such as older age and adenocarcinoma subtype, were associated with BM. Additionally, Asians/Pacific-Islanders (HR 1.83 CI: 1.01-3-33, p = 0.045) and American Indians/Alaska Natives (HR 4.79 CI 1.15-19.97, p = 0.032) had higher mortality rates, while surgical treatment and chemotherapy were linked to decreased mortality. Patients with BM had significantly worse overall survival (6 months vs. 21 months, p < 0.001).

CONCLUSION

BM in mCRC is uncommon, but it is associated with significantly worse outcomes, including markedly reduced overall survival. Our study highlights several critical factors associated with the presence of BM, such as older age and specific racial/ethnic groups, which may inform risk stratification and early-detection strategies. Our findings emphasize the need for heightened awareness and screening for BM in high-risk mCRC patients, as well as the inclusion of these patients in clinical trials to explore tailored therapeutic approaches aimed at improving survival and quality of life.

Deciphering the spatiotemporal transcriptional landscape of intestinal diseases (Review)

The intestines are the largest barrier organ in the human body. The intestinal barrier plays a crucial role in maintaining the balance of the intestinal environment and protecting the intestines from harmful bacterial invasion. Single‑cell RNA sequencing technology allows the detection of the different cell types in the intestine in two dimensions and the exploration of cell types that have not been fully characterized. The intestinal mucosa is highly complex in structure, and its proper functioning is linked to multiple structures in the proximal‑distal intestinal and luminal‑mucosal axes. Spatial localization is at the core of the efforts to explore the interactions between the complex structures. Spatial transcriptomics (ST) is a method that allows for comprehensive tissue analysis and the acquisition of spatially separated genetic information from individual cells, while preserving their spatial location and interactions. This approach also prevents the loss of fragile cells during tissue disaggregation. The emergence of ST technology allows us to spatially dissect enzymatic processes and interactions between multiple cells, genes, proteins and signals in the intestine. This includes the exchange of oxygen and nutrients in the intestine, different gradients of microbial populations and the role of extracellular matrix proteins. This regionally precise approach to tissue studies is gaining more acceptance and is increasingly applied in the investigation of disease mechanisms related to the gastrointestinal tract. Therefore, this review summarized the application of ST in gastrointestinal diseases.

Neoadjuvant Chemotherapy With Oxaliplatin and Fluoropyrimidine Versus Upfront Surgery for Locally Advanced Colon Cancer: The Randomized, Phase III OPTICAL Trial

PURPOSE

The role of neoadjuvant chemotherapy (NAC) in colon cancer remains unclear. This trial investigated whether 3 months of modified infusional fluorouracil, leucovorin, and oxaliplatin (mFOLFOX6) or capecitabine and oxaliplatin (CAPOX) as NAC could improve outcomes in patients with locally advanced colon cancer versus upfront surgery.

PATIENTS AND METHODS

OPTICAL was a randomized, phase III trial in patients with clinically staged locally advanced colon cancer (T3 with extramural spread into the mesocolic fat ≥5 mm or T4). Patients were randomly assigned 1:1 to receive six preoperative cycles of mFOLFOX6 or four cycles of CAPOX, followed by surgery and adjuvant chemotherapy (NAC group), or immediate surgery and the physician's choice of adjuvant chemotherapy (upfront surgery group). The primary end point was 3-year disease-free survival (DFS) assessed in the modified intention-to-treat (mITT) population.

RESULTS

Between January 2016 and April 2021, of the 752 patients enrolled, 744 patients were included in the mITT analysis (371 in the NAC group; 373 in the upfront surgery group). At a median follow-up of 48.0 months (IQR, 46.0-50.1), 3-year DFS rates were 82.1% in the NAC group and 77.5% in the upfront surgery group (stratified hazard ratio [HR], 0.74 [95% CI, 0.54 to 1.03]). The R0 resection was achieved in 98% of patients who underwent surgery in both groups. Compared with upfront surgery, NAC resulted in a 7% pathologic complete response rate (pCR), significantly lower rates of advanced tumor staging (pT3-4: 77% v 94%), lymph node metastasis (pN1-2: 31% v 46%), and potentially improved overall survival (stratified HR, 0.44 [95% CI, 0.25 to 0.77]).

CONCLUSION

NAC with mFOLFOX6 or CAPOX did not show a significant DFS benefit. However, this neoadjuvant approach was safe, resulted in substantial pathologic downstaging, and appears to be a viable therapeutic option for locally advanced colon cancer.

Oncological risks associated with the planned watch-and-wait strategy using total neoadjuvant treatment for rectal cancer: A narrative review

Overall survival benefit of total neoadjuvant treatment (TNT) remains unconfirmed. Thus, in our opinion, the main rationale for using TNT is a planned watch-and-wait (w&w) strategy to improve patients' long-term quality of life through organ preservation. The OPRA randomized trial, which examined a planned w&w strategy using TNT, showed a higher organ preservation rate but also a higher regrowth rate compared to studies on the opportunistic w&w strategy. Higher rates of complete clinical response with TNT did not improve disease-free survival compared to historical controls. Therefore, the gain in organ-sparing capability might not be balanced by the increased oncological risk. The ultimate local failure rate in the intention-to-treat analysis of the OPRA trial was 13% for induction chemotherapy and 16% for consolidation chemotherapy, which seems higher than expected compared to 8% in a meta-analysis of w&w studies or 12% after TNT and surgery in the PRODIGE-23 and RAPIDO trials, which enrolled patients with more advanced cancers than the OPRA trial. Other studies also suggest worse local control when surgery is delayed for radio-chemoresistant cancers. Our review questions the safety of the planned w&w strategy using TNT in unselected patients. To reduce the oncological risk while maintaining high organ preservation rates, we suggest that the planned w&w strategy using TNT requires a two-tier patient selection process: before treatment and after tumor response assessment at the midpoint of consolidation chemotherapy. These robust selections should identify patients who are unlikely to achieve organ preservation with TNT and would be better managed by preoperative chemoradiotherapy (without consolidation chemotherapy) and surgery, or by discontinuing consolidation chemotherapy and proceeding directly to surgery.

Clinical, Radiologic, and Surgical Features of Brain Metastases in Colorectal Cancer. A Strong Correlation Between Surgical Patterns and Outcome

BACKGROUND

Brain metastases (BMs) from colorectal cancer (CRC) are a small percentage of metastatic patients and surgery is considered the best choice to improve survival. While most research has focused on the risk of CRC spreading to the brain, no studies have examined the characteristics of BMs in relation to surgery and outcome. In this study, we evaluate the clinical and radiologic features of BMs from CRC patients who underwent surgery and analyze their outcomes.

METHODS

The study is a retrospective observational analysis that included a cohort of 31 patients affected by CRC surgically-treated for their related BMs. For all patients, clinical and surgical data (number, site, side, tumor and edema volume, and morphology) were recorded.

RESULTS

Analysis found that synchronous diagnosis and lesion morphology, particularly cystic versus solid, had the most significant impact on survival (6 vs. 22 months, P = 0.04). To compare BMs with cystic morphology to those with solid morphology, a multivariate analysis was conducted. No significant differences were observed between the 2 groups in terms of age, sex, clinical onset, or performance status. The analysis revealed no significant differences in localization with regard to site, tumor and edema volume, biology, or complications rate.

CONCLUSIONS

BMs derived from CRC have a significantly different prognosis depending on whether they present as a solid or cystic pattern. Although solid pattern is more common, cystic BMs in this tumor type are less frequent and are associated with a poorer prognosis, regardless of molecular expression, location, size, and adjuvant treatment.

Mechanisms of metastatic colorectal cancer

Despite extensive research and improvements in understanding colorectal cancer (CRC), its metastatic form continues to pose a substantial challenge, primarily owing to limited therapeutic options and a poor prognosis. This Review addresses the emerging focus on metastatic CRC (mCRC), which has historically been under-studied compared with primary CRC despite its lethality. We delve into two crucial aspects: the molecular and cellular determinants facilitating CRC metastasis and the principles guiding the evolution of metastatic disease. Initially, we examine the genetic alterations integral to CRC metastasis, connecting them to clinically marked characteristics of advanced CRC. Subsequently, we scrutinize the role of cellular heterogeneity and plasticity in metastatic spread and therapy resistance. Finally, we explore how the tumour microenvironment influences metastatic disease, emphasizing the effect of stromal gene programmes and the immune context. The ongoing research in these fields holds immense importance, as its future implications are projected to revolutionize the treatment of patients with mCRC, hopefully offering a promising outlook for their survival.

Validation of a Microfluidic Device Prototype for Cancer Detection and Identification: Circulating Tumor Cells Classification Based on Cell Trajectory Analysis Leveraging Cell-Based Modeling and Machine Learning

Microfluidic devices (MDs) present a novel method for detecting circulating tumor cells (CTCs), enhancing the process through targeted techniques and visual inspection. However, current approaches often yield heterogeneous CTC populations, necessitating additional processing for comprehensive analysis and phenotype identification. These procedures are often expensive, time-consuming, and need to be performed by skilled technicians. In this study, we investigate the potential of a cost-effective and efficient hyperuniform micropost MD approach for CTC classification. Our approach combines mathematical modeling of fluid-structure interactions in a simulated microfluidic channel with machine learning techniques. Specifically, we developed a cell-based modeling framework to assess CTC dynamics in erythrocyte-laden plasma flow, generating a large dataset of CTC trajectories that account for two distinct CTC phenotypes. Convolutional Neural Network (CNN) and Recurrent Neural Network (RNN) were then employed to analyze the dataset and classify these phenotypes. The results demonstrate the potential effectiveness of the hyperuniform micropost MD design and analysis approach in distinguishing between different CTC phenotypes based on cell trajectory, offering a promising avenue for early cancer detection.

How much do we know about the metastatic process?

Cancer cells can leave their primary sites and travel through the circulation to distant sites, where they lodge as disseminated cancer cells (DCCs), even during the early and asymptomatic stages of tumor progression. In experimental models and clinical samples, DCCs can be detected in a non-proliferative state, defined as cellular dormancy. This state can persist for extended periods until DCCs reawaken, usually in response to niche-derived reactivation signals. Therefore, their clinical detection in sites like lymph nodes and bone marrow is linked to poor survival. Current cancer therapy designs are based on the biology of the primary tumor and do not target the biology of the dormant DCC population and thus fail to eradicate the initial or subsequent waves of metastasis. In this brief review, we discuss the current methods for detecting DCCs and highlight new strategies that aim to target DCCs that constitute minimal residual disease to reduce or prevent metastasis formation. Furthermore, we present current evidence on the relevance of DCCs derived from early stages of tumor progression in metastatic disease and describe the animal models available for their study. We also discuss our current understanding of the dissemination mechanisms utilized by genetically less- and more-advanced cancer cells, which include the functional analysis of intermediate or hybrid states of epithelial-mesenchymal transition (EMT). Finally, we raise some intriguing questions regarding the clinical impact of studying the crosstalk between evolutionary waves of DCCs and the initiation of metastatic disease.

Surface-enhanced Raman scattering-based identification of breast cancer progression using extracellular vesicles-derived integrin α6β4

Detection of progression is of great importance to breast cancer treatment and can benefit patients. Limited by current detection technologies and biomarkers, early breast cancer progression diagnosis remains challenging. Researchers have found blood extracellular vesicles (EVs)-derived integrin α6β4 directly facilitate progression in breast cancer, enabling cancer detection. However, EVs size and heterogeneity hinder protein detection, masked by abundant background EVs. Hence, novel tools for efficient detection of EVs with high selectivity and low interference are significantly desired. Here, a new silver-coated gold nanorods SERS probe, termed as Au@Ag@IDA-B/4MSTP, based on DNA aptamer was established for the detection of integrin α6β4 derived from EVs. Validation of the Au@Ag@IDA-B/4MSTP probes using cell-culture-derived EVs revealed a LOD of 23 particles/μL for EVs detection. This tool was further confirmed to mimic the real state of cancer with subcutaneous tumor model and lung metastasis model in mice. With 10 μL of blood plasma and simple Raman analysis process, the test achieved 85.7 % sensitivity and 83.3 % specificity. Moreover, our method achieves a simplified approach that expedites the detection process. These results demonstrate the good detection performance of Au@Ag@IDA-B/4MSTP probes for EVs integrin α6β4, and suggest that this non-invasive approach could be a promising tool for early detection of breast cancer progression.

In vivo interaction screening reveals liver-derived constraints to metastasis

It is estimated that only 0.02% of disseminated tumour cells are able to seed overt metastases1. While this suggests the presence of environmental constraints to metastatic seeding, the landscape of host factors controlling this process remains largely unclear. Here, combining transposon technology2 and fluorescence niche labelling3, we developed an in vivo CRISPR activation screen to systematically investigate the interactions between hepatocytes and metastatic cells. We identify plexin B2 as a critical host-derived regulator of liver colonization in colorectal and pancreatic cancer and melanoma syngeneic mouse models. We dissect a mechanism through which plexin B2 interacts with class IV semaphorins on tumour cells, leading to KLF4 upregulation and thereby promoting the acquisition of epithelial traits. Our results highlight the essential role of signals from the liver parenchyma for the seeding of disseminated tumour cells before the establishment of a growth-promoting niche. Our findings further suggest that epithelialization is required for the adaptation of CRC metastases to their new tissue environment. Blocking the plexin-B2-semaphorin axis abolishes metastatic colonization of the liver and therefore represents a therapeutic strategy for the prevention of hepatic metastases. Finally, our screening approach, which evaluates host-derived extrinsic signals rather than tumour-intrinsic factors for their ability to promote metastatic seeding, is broadly applicable and lays a framework for the screening of environmental constraints to metastasis in other organs and cancer types.

Short- and long-term outcomes of surgical treatment for inguinal lymph node metastasis in rectal and anal canal adenocarcinoma

AIM

The significance of lymphadenectomy and its indications in patients with inguinal lymph node metastasis (ILNM) of anorectal adenocarcinoma is unclear. This study aimed to clarify the surgical outcomes and prognostic factors of inguinal lymphadenectomy for ILNM.

METHOD

This study included patients who underwent surgical resection for ILNM of rectal or anal canal adenocarcinoma with pathologically positive metastases between 1997 and 2011 at 20 participating centres in the Study Group for Inguinal Lymph Node Metastasis from Colorectal Cancer organized by the Japanese Society for Cancer of the Colon and Rectum. Clinicopathological characteristics and short- and long-term postoperative outcomes were retrospectively analysed.

RESULTS

In total, 107 patients were included. The primary tumour was in the rectum in 57 patients (53.3%) and in the anal canal in 50 (46.7%). The median number of ILNMs was 2.34. Postoperative complications of Clavien-Dindo Grade III or higher were observed in five patients. The 5-year overall survival rate was 38.8%. Multivariate analysis identified undifferentiated histological type (P < 0.001), pathological venous invasion (P = 0.01) and pathological primary tumour depth T0-2 (P = 0.01) as independent prognostic factors for poor overall survival.

CONCLUSION

The 5-year overall survival after inguinal lymph node dissection was acceptable, and it warrants consideration in more patients. Further larger-scale studies are needed in order to clarify the surgical indications.

Oncologic outcomes of screen-detected and non-screen-detected T1 colorectal cancers

BACKGROUND

The incidence of T1 colorectal cancer (CRC) has increased with the implementation of CRC screening programs. It is unknown whether the outcomes and risk models for T1 CRC based on non-screen-detected patients can be extrapolated to screen-detected T1 CRC. This study aimed to compare the stage distribution and oncologic outcomes of T1 CRC patients within and outside the screening program.

METHODS

Data from T1 CRC patients diagnosed between 2014 and 2017 were collected from 12 hospitals in the Netherlands. The presence of lymph node metastasis (LNM) at diagnosis was compared between screen-detected and non-screen-detected patients using multivariable logistic regression. Cox proportional hazard regression was used to analyze differences in the time to recurrence (TTR), metastasis-free survival (MFS), cancer-specific survival (CSS), and overall survival. Additionally, the performance of conventional risk factors for LNM was evaluated across the groups.

RESULTS

1803 patients were included (1114 [62%] screen-detected), with median follow-up of 51 months (interquartile range 30). The proportion of LNM did not significantly differ between screen- and non-screen-detected patients (12.6% vs. 8.9%; odds ratio 1.41; 95%CI 0.89-2.23); a prediction model for LNM performed equally in both groups. The 3- and 5-year TTR, MFS, and CSS were similar for patients within and outside the screening program. However, overall survival was significantly longer in screen-detected T1 CRC patients (adjusted hazard ratio 0.51; 95%CI 0.38-0.68).

CONCLUSIONS

Screen-detected and non-screen-detected T1 CRCs have similar stage distributions and oncologic outcomes and can therefore be treated equally. However, screen-detected T1 CRC patients exhibit a lower rate of non-CRC-related mortality, resulting in longer overall survival.

Frequency-dependent selection of neoantigens fosters tumor immune escape and predicts immunotherapy response

Cancer is an evolutionary process shaped by selective pressure from the microenvironments. However, recent studies reveal that certain tumors undergo neutral evolution where there is no detectable fitness difference amongst the cells following malignant transformation. Here, through computational modeling, we demonstrate that negative frequency-dependent selection (or NFDS), where the immune response against cancer cells depends on the clonality of neoantigens, can lead to an immunogenic landscape that is highly similar to neutral evolution. Crucially, NFDS promotes high antigenic heterogeneity and early immune evasion in hypermutable tumors, leading to poor responses to immune checkpoint blockade (ICB) therapy. Our model also reveals that NFDS is characterized by a negative association between average clonality and total burden of neoantigens. Indeed, this unique feature of NFDS is common in the whole-exome sequencing (WES) datasets (357 tumor samples from 275 patients) from four melanoma cohorts with ICB therapy and a non-small cell lung cancer (NSCLC) WES dataset (327 tumor samples from 100 patients). Altogether, our study provides quantitative evidence supporting the theory of NFDS in cancer, explaining the high prevalence of neutral-looking tumors. These findings also highlight the critical role of frequency-dependent selection in devising more efficient and predictive immunotherapies.

A Role of Effector CD 8 + T Cells Against Circulating Tumor Cells Cloaked with Platelets: Insights from a Mathematical Model

Cancer metastasis accounts for a majority of cancer-related deaths worldwide. Metastasis occurs when the primary tumor sheds cells into the blood and lymphatic circulation, thereby becoming circulating tumor cells (CTCs) that transverse through the circulatory system, extravasate the circulation and establish a secondary distant tumor. Accumulating evidence suggests that circulating effector CD 8 + T cells are able to recognize and attack arrested or extravasating CTCs, but this important antitumoral effect remains largely undefined. Recent studies highlighted the supporting role of activated platelets in CTCs's extravasation from the bloodstream, contributing to metastatic progression. In this work, a simple mathematical model describes how the primary tumor, CTCs, activated platelets and effector CD 8 + T cells participate in metastasis. The stability analysis reveals that for early dissemination of CTCs, effector CD 8 + T cells can present or keep secondary metastatic tumor burden at low equilibrium state. In contrast, for late dissemination of CTCs, effector CD 8 + T cells are unlikely to inhibit secondary tumor growth. Moreover, global sensitivity analysis demonstrates that the rate of the primary tumor growth, intravascular CTC proliferation, as well as the CD 8 + T cell proliferation, strongly affects the number of the secondary tumor cells. Additionally, model simulations indicate that an increase in CTC proliferation greatly contributes to tumor metastasis. Our simulations further illustrate that the higher the number of activated platelets on CTCs, the higher the probability of secondary tumor establishment. Intriguingly, from a mathematical immunology perspective, our simulations indicate that if the rate of effector CD 8 + T cell proliferation is high, then the secondary tumor formation can be considerably delayed, providing a window for adjuvant tumor control strategies. Collectively, our results suggest that the earlier the effector CD 8 + T cell response is enhanced the higher is the probability of preventing or delaying secondary tumor metastases.

Genomic characterization of cervical lymph node metastases in papillary thyroid carcinoma following the Chornobyl accident

Childhood radioactive iodine exposure from the Chornobyl accident increased papillary thyroid carcinoma (PTC) risk. While cervical lymph node metastases (cLNM) are well-recognized in pediatric PTC, the PTC metastatic process and potential radiation association are poorly understood. Here, we analyze cLNM occurrence among 428 PTC with genomic landscape analyses and known drivers (131I-exposed = 349, unexposed = 79; mean age = 27.9 years). We show that cLNM are more frequent in PTC with fusion (55%) versus mutation (30%) drivers, although the proportion varies by specific driver gene (RET-fusion = 71%, BRAF-mutation = 38%, RAS-mutation = 5%). cLNM frequency is not associated with other characteristics, including radiation dose. cLNM molecular profiling (N = 47) demonstrates 100% driver concordance with matched primary PTCs and highly concordant mutational spectra. Transcriptome analysis reveals 17 differentially expressed genes, particularly in the HOXC cluster and BRINP3; the strongest differentially expressed microRNA also is near HOXC10. Our findings underscore the critical role of driver alterations and provide promising candidates for elucidating the biological underpinnings of PTC cLNM.

Targeted Treatment against Cancer Stem Cells in Colorectal Cancer

The cancer stem cell (SC) theory proposes that a population of SCs serves as the driving force behind fundamental tumor processes, including metastasis, recurrence, and resistance to therapy. The standard of care for patients with stage III and high-risk stage II colorectal cancer (CRC) includes surgery and adjuvant chemotherapy. Fluoropyrimidines and their combination with oxaliplatin increased the cure rates, being able to eradicate the occult metastatic SC in a fraction of patients. The treatment for unresectable metastatic CRC is based on chemotherapy, antibodies to VEGF and EGFR, and tyrosine-kinase inhibitors. Immunotherapy is used in MSI-H tumors. Currently used drugs target dividing cells and, while often effective at debulking tumor mass, these agents have largely failed to cure metastatic disease. SCs are generated either due to genetic and epigenetic alterations in stem/progenitor cells or to the dedifferentiation of somatic cells where diverse signaling pathways such as Wnt/β-catenin, Hedgehog, Notch, TGF-β/SMAD, PI3K/Akt/mTOR, NF-κB, JAK/STAT, DNA damage response, and Hippo-YAP play a key role. Anti-neoplastic treatments could be improved by elimination of SCs, becoming an attractive target for the design of novel agents. Here, we present a review of clinical trials assessing the efficacy of targeted treatment focusing on these pathways in CRC.

Platelets favor the outgrowth of established metastases

Despite abundant evidence demonstrating that platelets foster metastasis, anti-platelet agents have low therapeutic potential due to the risk of hemorrhages. In addition, whether platelets can regulate metastasis at the late stages of the disease remains unknown. In this study, we subject syngeneic models of metastasis to various thrombocytopenic regimes to show that platelets provide a biphasic contribution to metastasis. While potent intravascular binding of platelets to tumor cells efficiently promotes metastasis, platelets further support the outgrowth of established metastases via immune suppression. Genetic depletion and pharmacological targeting of the glycoprotein VI (GPVI) platelet-specific receptor in humanized mouse models efficiently reduce the growth of established metastases, independently of active platelet binding to tumor cells in the bloodstream. Our study demonstrates therapeutic efficacy when targeting animals bearing growing metastases. It further identifies GPVI as a molecular target whose inhibition can impair metastasis without inducing collateral hemostatic perturbations.

Distinct molecular profiles drive multifaceted characteristics of colorectal cancer metastatic seeds

Metastasis of primary tumors remains a challenge for early diagnosis and prevention. The cellular properties and molecular drivers of metastatically competent clones within primary tumors remain unclear. Here, we generated 10-16 single cell-derived lines from each of three colorectal cancer (CRC) tumors to identify and characterize metastatic seeds. We found that intrinsic factors conferred clones with distinct metastatic potential and cellular communication capabilities, determining organ-specific metastasis. Poorly differentiated or highly metastatic clones, rather than drug-resistant clones, exhibited poor clinical prognostic impact. Personalized genetic alterations, instead of mutation burden, determined the occurrence of metastatic potential during clonal evolution. Additionally, we developed a gene signature for capturing metastatic potential of primary CRC tumors and demonstrated a strategy for identifying metastatic drivers using isogenic clones with distinct metastatic potential in primary tumors. This study provides insight into the origin and mechanisms of metastasis and will help develop potential anti-metastatic therapeutic targets for CRC patients.

Molecular Heterogeneity in Leiomyosarcoma and Implications for Personalised Medicine

OPINION STATEMENT

Leiomyosarcoma (LMS) is one of the more common subtypes of soft tissue sarcomas (STS), accounting for about 20% of cases. Differences in anatomical location, risk of recurrence and histomorphological variants contribute to the substantial clinical heterogeneity in survival outcomes and therapy responses observed in patients. There is therefore a need to move away from the current one-size-fits-all treatment approach towards a personalised strategy tailored for individual patients. Over the past decade, tissue profiling studies have revealed key genomic features and an additional layer of molecular heterogeneity among patients, with potential utility for optimal risk stratification and biomarker-matched therapies. Furthermore, recent studies investigating intratumour heterogeneity and tumour evolution patterns in LMS suggest some key features that may need to be taken into consideration when designing treatment strategies and clinical trials. Moving forward, national and international collaborative efforts to aggregate expertise, data, resources and tools are needed to achieve a step change in improving patient survival outcomes in this disease of unmet need.

Considerations for using potential surrogate endpoints in cancer screening trials

The requirement of large-scale expensive cancer screening trials spanning decades creates considerable barriers to the development, commercialisation, and implementation of novel screening tests. One way to address these problems is to use surrogate endpoints for the ultimate endpoint of interest, cancer mortality, at an earlier timepoint. This Review aims to highlight the issues underlying the choice and use of surrogate endpoints for cancer screening trials, to propose criteria for when and how we might use such endpoints, and to suggest possible candidates. We present the current landscape and challenges, and discuss lessons and shortcomings from the therapeutic trial setting. It is hugely challenging to validate a surrogate endpoint, even with carefully designed clinical studies. Nevertheless, we consider whether there are candidates that might satisfy the requirements defined by research and regulatory bodies.

Overcoming Xenoantigen Immunity to Enable Cellular Tracking and Gene Regulation with Immune-competent "NoGlow" Mice

The ability to temporally regulate gene expression and track labeled cells makes animal models powerful biomedical tools. However, sudden expression of xenobiotic genes [e.g., GFP, luciferase (Luc), or rtTA3] can trigger inadvertent immunity that suppresses foreign protein expression or results in complete rejection of transplanted cells. Germline exposure to foreign antigens somewhat addresses these challenges; however, native fluorescence and bioluminescence abrogates the utility of reporter proteins and highly spatiotemporally restricted expression can lead to suboptimal xenoantigen tolerance. To overcome these unwanted immune responses and enable reliable cell tracking/gene regulation, we developed a novel mouse model that selectively expresses antigen-intact but nonfunctional forms of GFP and Luc, as well as rtTA3, after CRE-mediated recombination. Using tissue-specific CREs, we observed model and sex-based differences in immune tolerance to the encoded xenoantigens, illustrating the obstacles of tolerizing animals to foreign genes and validating the utility of these "NoGlow" mice to dissect mechanisms of central and peripheral tolerance. Critically, tissue unrestricted NoGlow mice possess no detectable background fluorescence or luminescence and exhibit limited adaptive immunity against encoded transgenic xenoantigens after vaccination. Moreover, we demonstrate that NoGlow mice allow tracking and tetracycline-inducible gene regulation of triple-transgenic cells expressing GFP/Luc/rtTA3, in contrast to transgene-negative immune-competent mice that eliminate these cells or prohibit metastatic seeding. Notably, this model enables de novo metastasis from orthotopically implanted, triple-transgenic tumor cells, despite high xenoantigen expression. Altogether, the NoGlow model provides a critical resource for in vivo studies across disciplines, including oncology, developmental biology, infectious disease, autoimmunity, and transplantation.

SIGNIFICANCE

Multitolerant NoGlow mice enable tracking and gene manipulation of transplanted tumor cells without immune-mediated rejection, thus providing a platform to investigate novel mechanisms of adaptive immunity related to metastasis, immunotherapy, and tolerance.

A radiomics and genomics-derived model for predicting metastasis and prognosis in colorectal cancer

Approximately 50% of colorectal cancer (CRC) patients would develop metastasis with poor prognosis, therefore, it is necessary to effectively predict metastasis in clinical treatment. In this study, we aimed to establish a machine-learning model for predicting metastasis in CRC patients by considering radiomics and transcriptomics simultaneously. Here, 1023 patients with CRC from three centers were collected and divided into five queues (Dazhou Central Hospital n = 517, Nanchong Central Hospital n = 120 and the Cancer Genome Atlas (TCGA) n = 386). A total of 854 radiomics features were extracted from tumor lesions on CT images, and 217 differentially expressed genes were obtained from non-metastasis and metastasis tumor tissues using RNA sequencing. Based on radiotranscriptomic (RT) analysis, a novel RT model was developed and verified through genetic algorithms (GA). Interleukin (IL)-26, a biomarker in RT model, was verified for its biological function in CRC metastasis. Furthermore, 15 radiomics variables were screened through stepwise regression, which was highly correlated with the IL26 expression level. Finally, a radiomics model (RA) was established by combining GA and stepwise regression analysis with radiomics features. The RA model exhibited favorable discriminatory ability and accuracy for metastasis prediction in two independent verification cohorts. We designed multicenter, multi-scale cohorts to construct and verify novel combined radiomics and genomics models for predicting metastasis in CRC. Overall, RT model and RA model might help clinicians in directing personalized diagnosis and therapeutic regimen selection for patients with CRC.

Multiregion WES of metastatic pancreatic neuroendocrine tumors revealed heterogeneity in genomic alterations, immune microenvironment and evolutionary patterns

Pancreatic neuroendocrine tumors (PanNETs), though uncommon, have a high likelihood of spreading to other body parts. Previously, the genetic diversity and evolutionary patterns in metastatic PanNETs were not well understood. To investigate this, we performed multiregion sampling whole-exome sequencing (MRS-WES) on samples from 10 patients who had not received prior treatment for metastatic PanNETs. This included 29 primary tumor samples, 31 lymph node metastases, and 15 liver metastases. We used the MSK-MET dataset for survival analysis and validation of our findings. Our research indicates that mutations in the MEN1/DAXX genes might trigger the early stages of PanNET development. We categorized the patients based on the presence (MEN1/DAXXmut, n = 7) or absence (MEN1/DAXXwild, n = 3) of these mutations. Notable differences were observed between the two groups in terms of genetic alterations and clinically relevant mutations, confirmed using the MSK-MET dataset. Notably, patients with mutations in MEN1/DAXX/ATRX genes had a significantly longer median overall survival compared to those without these mutations (median not reached vs. 43.63 months, p = 0.047). Multiplex immunohistochemistry (mIHC) analysis showed a more prominent immunosuppressive environment in metastatic tumors, especially in patients with MEN1/DAXX mutations. These findings imply that MEN1/DAXX mutations lead PanNETs through a unique evolutionary path. The disease's progression pattern indicates that PanNETs can spread early, even before clinical detection, highlighting the importance of identifying biomarkers related to metastasis to guide personalized treatment strategies.

Expression Analysis of Early Metastatic Seeding of Colorectal Cancer

BACKGROUND

Distant metastasis is the leading cause of death in patients with colorectal cancer (CRC). Tumor dissemination for metastasis formation occurs in advanced cancers and also during early stages of tumorigenesis. Here, we investigated the genes involved in early metastatic seeding of CRC using gene expression analysis.

PATIENTS AND METHODS

We performed a cDNA microarray using specimens resected from stages I-II CRC with and without metachronous metastatic recurrence. For the candidate genes, we immunohistochemically validated protein expression using a tissue microarray of stages I-III CRC.

RESULTS

The expression of TROP2, VWCE, and BMP7 was upregulated in the recurrence group rather than in the non-recurrence group. Protein expression analysis revealed significant association of these genes with distant metastatic recurrence. The specimens with high expression of BMP7 showed worse recurrence-free survival (RFS; p = 0.02). Those with high expression of TROP2 and VWCE showed worse overall survival (OS) and RFS (TROP2: p = 0.01 and p = 0.03; VWCE: p < 0.05 and p < 0.001, respectively). In the multivariate analysis, high expression of VWCE and BMP7 was an independent predictor of recurrence [VWCE: hazard ratio (HR) 3.41, p < 0.001; BMP7: HR 2.93, p = 0.005]. In contrast, TROP2 was an independent prognostic factor for OS (HR 4.58, p = 0.03).

CONCLUSIONS

Gene expression analysis revealed that TROP2, VWCE, and BMP7 were involved in early metastatic seeding. The high expression of these genes may warrant careful surveillance or adjuvant therapy, even in stages I-II CRC cases.

Laennec's approach for central liver resection of colorectal cancer liver metastasis adjacent to the hepatic hilum that occurred 10 years after colectomy: A case report

INTRODUCTION AND IMPORTANCE

Colorectal cancer ranks as one of the most common cancer globally. About half of the patients experience a disease recurrence in the form of сolorectal cancer liver metastasis (CRLM) within the first 5 years of the course of the disease. However, there are rare cases of delayed onset of liver metastasis, that occur after cessation of standard follow-up.

CASE PRESENTATION

A 38-year-old woman was referred to our institute with a metastatic liver mass adjacent to the liver hilum. The patient had sigmoid colectomy 10 years ago. After 6 cycles of chemotherapy, she underwent a central liver resection: Sg4, Sg5, Sg8v + middle hepatic vein with surgical skeletonization of 1st and 2nd order hepatic pedicles. The patient was discharged on 5th post-operative day. After 18th month of follow-up, the patient was alive without any signs of recurrence.

CLINICAL DISCUSSION

The recommended follow-up of colorectal cancer patients is 5 years. However, there are rare instances of late metachronous liver recurrences, that suggest the necessity of more continuous surveillance. For patients with CRLM surgical resection is considered the most radical treatment of choice. The anatomy of Laennec's capsule allows the precise isolation of hepatic pedicles and can facilitate anatomical hepatectomy.

CONCLUSION

We present a rare case report of borderline-resectable CRLM successfully treated with central liver resection with application of Laennec's approach a decade after the resection of a primary colorectal tumor.

Zebrafish xenograft as a tool for the study of colorectal cancer: a review

Colorectal cancer (CRC) is the second leading cause of cancer-related death, mostly due to metastatic disease and the fact that many patients already show signs of metastasis at the time of first diagnosis. Current CRC therapies negatively impact patients' quality of life and have little to no effect on combating the tumor once the dissemination has started. Danio rerio (zebrafish) is a popular animal model utilized in cancer research. One of its main advantages is the ease of xenograft transplantation due to the fact that zebrafish larvae lack the adaptative immune system, guaranteeing the impossibility of rejection. In this review, we have presented the many works that choose zebrafish xenograft as a tool for the study of CRC, highlighting the methods used as well as the promising new therapeutic molecules that have been identified due to this animal model.

Immune evasion of dormant disseminated tumor cells is due to their scarcity and can be overcome by T cell immunotherapies

The period between "successful" treatment of localized breast cancer and the onset of distant metastasis can last many years, representing an unexploited window to eradicate disseminated disease and prevent metastases. We find that the source of recurrence-disseminated tumor cells (DTCs) -evade endogenous immunity directed against tumor neoantigens. Although DTCs downregulate major histocompatibility complex I, this does not preclude recognition by conventional T cells. Instead, the scarcity of interactions between two relatively rare populations-DTCs and endogenous antigen-specific T cells-underlies DTC persistence. This scarcity is overcome by any one of three immunotherapies that increase the number of tumor-specific T cells: T cell-based vaccination, or adoptive transfer of T cell receptor or chimeric antigen receptor T cells. Each approach achieves robust DTC elimination, motivating discovery of MHC-restricted and -unrestricted DTC antigens that can be targeted with T cell-based immunotherapies to eliminate the reservoir of metastasis-initiating cells in patients.

Integrated multi-omics profiling to dissect the spatiotemporal evolution of metastatic hepatocellular carcinoma

Comprehensive molecular analyses of metastatic hepatocellular carcinoma (HCC) are lacking. Here, we generate multi-omic profiling of 257 primary and 176 metastatic regions from 182 HCC patients. Primary tumors rich in hypoxia signatures facilitated polyclonal dissemination. Genomic divergence between primary and metastatic HCC is high, and early dissemination is prevalent. The remarkable neoantigen intratumor heterogeneity observed in metastases is associated with decreased T cell reactivity, resulting from disruptions to neoantigen presentation. We identify somatic copy number alterations as highly selected events driving metastasis. Subclones without Wnt mutations show a stronger selective advantage for metastasis than those with Wnt mutations and are characterized by a microenvironment rich in activated fibroblasts favoring a pro-metastatic phenotype. Finally, metastases without Wnt mutations exhibit higher enrichment of immunosuppressive B cells that mediate terminal exhaustion of CD8+ T cells via HLA-E:CD94-NKG2A checkpoint axis. Collectively, our results provide a multi-dimensional dissection of the complex evolutionary process of metastasis.

Curcumin targets miR-134-5p to suppress the progression of colorectal cancer through regulating the CDCA3/CDK1 pathway

It has been reported the anti-tumor action of curcumin on colorectal cancer. In this study, we aimed to explore the potential mechanisms underlying curcumin in the development of colorectal cancer. CCK-8, EdU, flow cytometry, and transwell invasion assays were conducted to investigate the function role of curcumin in cell proliferation, apoptosis, and invasion. The level of miR-134-5p and CDCA3 was determined using RT-qPCR analysis. Western blot was applied for detecting the levels of c-myc, MMP9, CDCA3, and CDK1. Dual-luciferase reporter assay was used to evaluate the relationship between miR-134-5p and CDCA3, and IP assay was performed to examine the interaction between CDCA3 and CDK1. Additionally, SW620 cells were injected into the mice to form the xenograft tumor model. Curcumin treatment repressed cell growth and invasion, and induced cell apoptosis in HCT-116 and SW620 cells. Curcumin elevated miR-134-5p expression and restrained CDCA3 expression in HCT-116 and SW620 cells. MiR-134-5p inhibitor or CDCA3 overexpression could restore the effects of curcumin on cell growth, apoptosis, and invasion in HCT-116 and SW620 cells. MiR-134-5p targeted CDCA3, and CDCA3 could rescue the repressive effects of miR-134-5p on the progression of colorectal cancer. Moreover, CDCA3 interacted with CDK1, and CDK1 overexpression blocked the suppressive effects of CDCA3 downregulation on the development of colorectal cancer. In addition, curcumin treatment repressed tumor growth in colorectal cancer via increasing miR-134-5p and downregulating CDCA3 and CDK1 expression in vivo. Our findings provided the evidence that curcumin upregulated miR-134-5p to inhibit the progression of colorectal cancer by regulating CDCA3/CDK1 pathway.

Engineering Heterogeneous Tumor Models for Biomedical Applications

Tumor tissue engineering holds great promise for replicating the physiological and behavioral characteristics of tumors in vitro. Advances in this field have led to new opportunities for studying the tumor microenvironment and exploring potential anti-cancer therapeutics. However, the main obstacle to the widespread adoption of tumor models is the poor understanding and insufficient reconstruction of tumor heterogeneity. In this review, the current progress of engineering heterogeneous tumor models is discussed. First, the major components of tumor heterogeneity are summarized, which encompasses various signaling pathways, cell proliferations, and spatial configurations. Then, contemporary approaches are elucidated in tumor engineering that are guided by fundamental principles of tumor biology, and the potential of a bottom-up approach in tumor engineering is highlighted. Additionally, the characterization approaches and biomedical applications of tumor models are discussed, emphasizing the significant role of engineered tumor models in scientific research and clinical trials. Lastly, the challenges of heterogeneous tumor models in promoting oncology research and tumor therapy are described and key directions for future research are provided.

Surgical Primary Tumor Resection Reduces Accumulation of CD11b+ Myeloid Cells in the Lungs Augmenting the Efficacy of an Intranasal Cancer Vaccination against Secondary Lung Metastasis

A hallmark of effective cancer treatment is the prevention of tumor reoccurrence and metastasis to distal organs, which are responsible for most cancer deaths. However, primary tumor resection is expected to be curative as most solid tumors have been shown both experimentally and clinically to accelerate metastasis to distal organs including the lungs. In this study, we evaluated the efficacy of our engineered nasal nano-vaccine (CpG-NP-Tag) in reducing accelerated lung metastasis resulting from primary tumor resection. Cytosine-phosphate-guanine oligonucleotide [CpG ODN]-conjugated nanoparticle [NP] encapsulating tumor antigen [Tag] (CpG-NP-Tag) was manufactured and tested in vivo using a syngeneic mouse mammary tumor model following intranasal delivery. We found that our nasal nano-vaccine (CpG-NP-Tag), compared to control NPs administered after primary mammary tumor resection, significantly reduced lung metastasis in female BALB/c mice subjected to surgery (surgery mice). An evaluation of vaccine efficacy in both surgery and non-surgery mice revealed that primary tumor resection reduces CD11b+ monocyte-derived suppressor-like cell accumulation in the lungs, allowing increased infiltration of vaccine-elicited T cells (IFN-γ CD8+ T cells) in the lungs of surgery mice compared to non-surgery mice. These findings suggest that the combination of the target delivery of a nasal vaccine in conjunction with the standard surgery of primary tumors is a plausible adjunctive treatment against the establishment of lung metastasis.

The lncRNA FENDRR inhibits colorectal cancer progression via interacting with and triggering GSTP1 ubiquitination by FBX8

Background

Colorectal cancer (CRC) is characterized by its aggressiveness and high fatality rate. Long noncoding RNAs (lncRNAs) as molecular scaffolding in CRC have received little attention.

Methods

The TCGA database was used to find putative anti-oncogenic lncRNAs in CRC. The effect of FENDRR on CRC was evaluated using the colony formation assay, transwell assays, and wound healing assays, and FENDRR expression was validated by qRT-PCR. The location of the FENDRR binding proteins was determined by an RNA pull-down experiment, and the retrieved proteins were recognized by mass spectrometry. RNA immunoprecipitation (RIP) studies were used to demonstrate the interaction of GSTP1, FBX8, and FENDRR. Co-IP and immunofluorescence were utilized to confirm the connection between GSTP1 and FBX8. To determine the precise signaling pathways implicated in the action of FENDRR in CRC, we performed next-generation sequencing (NGS) on CRC cells transfected with a vector overexpressing FENDRR.

Results

The expression of FENDRR was significantly downregulated in CRC tissue and cells. The results of the function experiments showed that overexpression of FENDRR reduced CRC cells' ability to proliferation, invasion, migration and tube formation. In terms of mechanism, FENDRR could bind both GSTP1 and FBX8, act as a molecular scaffold, and utilize FBX8 to regulate the stability of GSTP1's protein. Additionally, the outcomes of NGS and qRT-PCR demonstrated that the expression of genes linked to the HIF-1 pathway was down-regulated following FENDRR overexpression. Lastly, rescue tests demonstrated that overexpression of GSTP1 in CRC cells could completely restore the inhibition induced by FENDRR.

Conclusion

In this study, we found that the molecular scaffolding protein FENDRR regulates the ubiquitination of GSTP1 and the suppression of the HIF-1 signaling pathway in the development of CRC. Our research provides more evidence of FENDRR's crucial role in the emergence of CRC and identifies it as a potential therapeutic target for CRC patients.

Cancer metastasis under the magnifying glass of epigenetics and epitranscriptomics

Most of the cancer-associated mortality and morbidity can be attributed to metastasis. The role of epigenetic and epitranscriptomic alterations in cancer origin and progression has been extensively demonstrated during the last years. Both regulations share similar mechanisms driven by DNA or RNA modifiers, namely writers, readers, and erasers; enzymes responsible of respectively introducing, recognizing, or removing the epigenetic or epitranscriptomic modifications. Epigenetic regulation is achieved by DNA methylation, histone modifications, non-coding RNAs, chromatin accessibility, and enhancer reprogramming. In parallel, regulation at RNA level, named epitranscriptomic, is driven by a wide diversity of chemical modifications in mostly all RNA molecules. These two-layer regulatory mechanisms are finely controlled in normal tissue, and dysregulations are associated with every hallmark of human cancer. In this review, we provide an overview of the current state of knowledge regarding epigenetic and epitranscriptomic alterations governing tumor metastasis, and compare pathways regulated at DNA or RNA levels to shed light on a possible epi-crosstalk in cancer metastasis. A deeper understanding on these mechanisms could have important clinical implications for the prevention of advanced malignancies and the management of the disseminated diseases. Additionally, as these epi-alterations can potentially be reversed by small molecules or inhibitors against epi-modifiers, novel therapeutic alternatives could be envisioned.