Acetylation of ELMO1 correlates with Rac1 activity and colorectal cancer progress.

Acetylation, a critical regulator of diverse cellular processes, holds significant implications in various cancer contexts. Further understanding of the acetylation patterns of key cancer-driven proteins is crucial for advancing therapeutic strategies in cancer treatment. This study aimed to unravel the acetylation patterns of Engulfment and Cell Motility Protein 1 (ELMO1) and its relevance to the pathogenesis of colorectal cancer (CRC). Immunoprecipitation and mass spectrometry precisely identified lysine residue 505 (K505) as a central acetylation site in ELMO1. P300 emerged as the acetyltransferase for ELMO1 K505 acetylation, while SIRT2 was recognized as the deacetylase. Although K505 acetylation minimally affected ELMO1's localization and stability, it played a crucial role in mediating ELMO1-Dock180 interaction, thereby influencing Rac1 activation. Functionally, ELMO1 K505 acetylation proved to be a pivotal factor in CRC progression, exerting its influence on key cellular processes. Clinical analysis of CRC samples unveiled elevated ELMO1 acetylation in primary tumors, indicating a potential association with CRC pathologies. This work provides insights into ELMO1 acetylation and its significance in advancing potentially therapeutic interventions in CRC treatment.

High KRT17 expression in tumour budding indicates immunologically 'hot' tumour budding and predicts good survival in patients with colorectal cancer.

Objectives: Emerging evidence has demonstrated that tumour budding (TB) is negatively associated with T-lymphocyte infiltration in CRC. Despite extensive research, the molecular characteristics of immunologically 'hot' TB remain poorly understood. Methods: We quantified the number of TB by haematoxylin-eosin (H&E) sections and the densities of CD3+ and CD8+ T-lymphocytes by immunohistochemistry in a CRC cohort of 351 cases who underwent curative resection. We analysed the differential expression and T-lymphocyte infiltration score of 37 human epithelial keratins in CRC using RNA sequencing from the TCGA dataset. In 278 TB-positive cases, KRT17 expression was evaluated in tumour centre (TC) and TB with a staining score. Patient demographic, clinicopathological features and survival rates were analysed. Results: In a CRC cohort of 351 cases, low-grade TB was associated with high CD3+ and CD8+ T-cell densities in the invasive margin (IM) but not in the TC. Of 37 human epithelial keratins, only KRT17 expression in TB had an apparent association with TB-grade and T-lymphocyte infiltration. In 278 TB-positive cases, high KRT17 expression in TB (KRT17TB) was negatively associated with low-grade TB and positively associated with high CD3+ and CD8+ T-cell densities in IM. High KRT17TB predicted early tumour grade, absence of lymph node metastasis and absence of tumour deposits. Additionally, patients with high KRT17TB had good overall survival and disease-free survival. Notably, low KRT17TB can specifically identify those patients with a poor prognosis among colorectal cancer patients with low TB and high T-lymphocyte infiltration. Conclusions: KRT17 can be employed as a new indicator for distinguishing different immunological TBs.

KRT17 Promotes T-lymphocyte Infiltration Through the YTHDF2-CXCL10 Axis in Colorectal Cancer.

Poor infiltration of T lymphocytes has been regarded as a crucial mechanism of tumor immune escape. Here, we demonstrate a protective role of KRT17 in colorectal cancer, where KRT17 reversed the tumor immunosuppressive microenvironment by increasing T-lymphocyte infiltration. High-throughput RNA sequencing suggested that KRT17 was significantly upregulated in deficient mismatch repair (dMMR) tumors compared with proficient mismatch repair (pMMR) tumors. In a colorectal cancer cohort of 446 cases, KRT17 expression positively correlated with better clinical outcomes. Krt17 overexpression decreased xenograft tumor growth in immune-competent mice. T-cell depletion in a murine model showed that the presence of T lymphocytes was necessary for Krt17-mediated disruption of tumorigenesis. Mass spectrometry and coimmunoprecipitation assays suggested KRT17 caused YTHDF2 degradation through the ubiquitin-proteasome system. Through high-throughput RNA immunoprecipitation sequencing, we found that CXCL10 was the target gene of the N6-methyladenosine (m6A) "reader" YTHDF2. KRT17 synergized with anti-PD-1 for better tumor control in an immunotherapy-resistant murine model. In a cohort of patients with colorectal cancer receiving pembrolizumab, high KRT17 expression was found within the tumors of responders. Collectively, we elucidated a critical role of KRT17 in colorectal cancer to prevent immune escape. These findings present new insights into potential therapeutic strategies and effective markers of immunotherapy reactivity against pMMR tumors.

A novel protein encoded by circINSIG1 reprograms cholesterol metabolism by promoting the ubiquitin-dependent degradation of INSIG1 in colorectal cancer.

BACKGROUND: Hypoxia is a hallmark of solid tumors and leads to the metabolic reprogramming of cancer cells. The role of epigenetic regulation between hypoxia and aberrant cholesterol metabolism in colorectal cancer (CRC) remains elusive. METHODS: Hypoxia-responsive circular RNAs (circRNAs) were identified by high throughput RNA sequencing between CRC cells cultured under normoxia or hypoxia. The protein-coding potential of circINSIG1 was identified by polysome profiling and LC-MS. The function of circINSIG1 was validated in vitro and in vivo by gain or loss of function assays. Mechanistic results were concluded by immunoprecipitation analyses. RESULTS: A novel hypoxia-responsive circRNA named circINSIG1 was identified, which was upregulated in CRC tissues and correlated with advanced clinical stages and poor survival. Mechanistically, circINSIG1 encoded a 121 amino acid protein circINSIG1-121 to promote K48-linked ubiquitination of the critical cholesterol metabolism regulator INSIG1 at lysine 156 and 158 by recruiting CUL5-ASB6 complex, a ubiquitin E3 ligase complex, thereby inducing cholesterol biosynthesis to promote CRC proliferation and metastasis. The orthotopic xenograft tumor models and patient-derived xenograft models further identified the role of circINSIG1 in CRC progression and potential therapeutic target of CRC. CONCLUSIONS: circINSIG1 presents an epigenetic mechanism which provides insights into the crosstalk between hypoxia and cholesterol metabolism, and provides a promising therapeutic target for the treatment of CRC.

Engulfment and cell motility protein 1 fosters reprogramming of tumor-associated macrophages in colorectal cancer.

Functional reprogramming of tumor-associated macrophages (TAMs) is crucial to their potent tumor-supportive capacity. However, the molecular mechanism behind the reprogramming process remains poorly understood. Here, we identify engulfment and cell motility protein 1 (ELMO1) as a crucial player for TAM reprogramming in colorectal cancer (CRC). The expression of ELMO1 in stromal but not epithelial tumor cells was positively associated with advanced clinical stage and poor disease-free survival in CRC. An increase in ELMO1 expression was specifically found in TAMs, but not in other multiple nonmalignant stromal cells. Gain- and loss-of-function assays indicated ELMO1 reprogrammed macrophages to a TAM-like phenotype through Rac1 activation. In turn, ELMO1-reprogrammed macrophages were shown to not only facilitate the malignant behaviors of CRC cells but exhibited potent phagocytosis of tumor cells. Taken together, our work underscores the importance of ELMO1 in determining functional reprogramming of TAMs and could provide new insights on potential therapeutic strategies against CRC.

Transanal total mesorectal excision combined with intersphincteric resection has similar long-term oncological outcomes to laparoscopic abdominoperineal resection in low rectal cancer: a propensity score-matched cohort study.

Background: Transanal total mesorectal excision (taTME) or intersphincteric resection (ISR) has recently proven to be a valid and safe surgical procedure for low rectal cancer. However, studies focusing on the combination of these two technologies are limited. This study aimed to evaluate perioperative results, long-term oncologic outcomes, and anorectal functions of patients with low rectal cancer undergoing taTME combined with ISR, by comparing with those of patients undergoing laparoscopic abdominoperineal resection (laAPR). Methods: After 1:1 propensity score matching, 200 patients with low rectal cancer who underwent laAPR (n = 100) or taTME combined with ISR (n = 100) between September 2013 and November 2019 were included. Patient demographics, clinicopathological characteristics, oncological outcomes, and anal functional results were analysed. Results: Patients in the taTME-combined-with-ISR group had less intraoperative blood loss (79.6 ± 72.6 vs 107.3 ± 65.1 mL, P = 0.005) and a lower rate of post-operative complications (22.0% vs 44.0%, P < 0.001) than those in the laAPR group. The overall local recurrence rates were 7.0% in both groups within 3 years after surgery. The 3-year disease-free survival rates were 86.3% in the taTME-combined-with-ISR group and 75.1% in the laAPR group (P = 0.056), while the 3-year overall survival rates were 96.7% and 94.2%, respectively (P = 0.319). There were 39 patients (45.3%) in the taTME-combined-with-ISR group who developed major low anterior resection syndrome, whereas 61 patients (70.9%) had good post-operative anal function (Wexner incontinence score ≤ 10). Conclusion: We found similar long-term oncological outcomes for patients with low rectal cancer undergoing laAPR and those undergoing taTME combined with ISR. Patients receiving taTME combined with ISR had acceptable post-operative anorectal function.

A Positive Feedback Loop between Inactive VHL-Triggered Histone Lactylation and PDGFRß Signaling Drives Clear Cell Renal Cell Carcinoma Progression.

Inactive von Hippel-Lindau (VHL) is linked to metabolic reprogramming and plays pivotal roles in the pathogenesis of clear cell renal cell carcinoma (ccRCC). Here, we identify a previously unknown oncogenic role for inactive VHL in actively triggering histone lactylation to promote ccRCC progression. In patients with ccRCC, inactive VHL positively correlates with the presence of histone lactylation, and high levels of histone lactylation indicates poor patient prognosis. Inactive VHL-triggered histone lactylation contributes to ccRCC progression by activating the transcription of platelet-derived growth factor receptor ß (PDGFRß). In turn, PDGFRß signaling is shown to stimulate histone lactylation, thereby forming an oncogenic positive feedback loop in ccRCC. Target correction of aberrant histone lactylation represses the growth and metastasis of ccRCC in vivo. More importantly, the combined inhibition of histone lactylation and PDGFRß significantly reinforces the therapeutic efficacy. This work underscores the importance of histone lactylation in facilitating ccRCC progression and suggests targeting the positive feedback loop between histone lactylation and PDGFRß signaling might provide a promising therapeutic strategy for ccRCC patients.

Transanal versus Laparoscopic Total Mesorectal Excision in Male Patients with Low Tumor Location after Neoadjuvant Therapy: A Propensity Score-Matched Cohort Study.

Background: Since Sylla and Lacy successfully reported the transanal total mesorectal excision in 2010, taTME was considered to have the potential to overcome some problematic laparoscopic cases in male, low advanced rectal cancer. However, the evidence is still lacking. This study compared the short and long outcomes of taTME with laTME in these "challenging" patients to explore the advantages of taTME among the patients. Method: After propensity score matching analysis, 106 patients were included in each group from 325 patients who met the including standard. Statistical analysis was used to compare the differences of perioperative outcomes, histopathological results, and survival results between taTME and laTME groups. Results: The mean time of pelvic operation in the taTME group was significantly shorter than in the laTME group (62.2 ± 14.2 mins vs 81.1 ± 18.9 mins, P = 0.003). The complication incidence rate and the rate of protective loop ileostomy in the taTME group were significantly lower than those in the laTME group (19.8% vs 38.7%, P = 0.003 and 70.8% vs 92.5%, P < 0.001). In long-term result, there was no significant difference between the two groups for 3-year OS (87.3% vs 85.4%, P = 0.86) or 3-year DFS (74.9% vs 70.1%, P = 0.92). The 2-year cumulative local recurrence rate was similar between the two groups (1.1% vs 5.8%, P = 0.22). Conclusion: This study demonstrated that taTME might reduce the incidence of postoperative complications, especially of anastomotic leakage in these "challenging" patients. taTME may be considered to have clear advantages for "challenging" patients.

Three-year outcomes of transanal total mesorectal excision versus standard laparoscopic total mesorectal excision for mid and low rectal cancer.

INTRODUCTION: Since transanal total mesorectal excision (taTME) was introduced, it has become an important topic in rectal cancer treatment. Many previous studies reported positive relevant short-term results, histopathological results, and associated complications. Recently, concerns regarding the oncological safety of taTME have been raised due to reports showing high local recurrences (LR) rates. Therefore, this study aimed to compare the 3-year outcomes between taTME and laparoscopic total mesorectal excision (laTME) for mid-low rectal cancer. METHODS: A total of 104 patients who underwent taTME were matched with 208 patients treated by laTME. The primary endpoint was 3-year LR rate; secondary endpoints in this matched-cohort study included the perioperative outcomes and histopathological outcomes. RESULTS: taTME was associated with lower permanent ostomy rate (1% vs 13.5%) and lower conversion rate (0% vs 3.4%) compared to laTME. A similar quality of resected specimens was detected for each group. In both groups, the local recurrence rate was 3.8%. Within 3 years after surgery, the disease-free survival (DFS) rates were 78.8% in the taTME group and 76.9% in the laTME group (P = 0.640), while the overall survival (OS) rates were 93.3% in the taTME group and 89.9% in the laTME group (P = 0.327). CONCLUSION: No significant differences regarding 3-year local recurrence rate (3.8%) were observed in the taTME group compared to laTME group.

Transanal Total Mesorectal Excision in Mid-Low Rectal Cancer: Evaluation of the Learning Curve and Comparison of Short-term Results With Standard Laparoscopic Total Mesorectal Excision.

BACKGROUND: Ever since transanal total mesorectal excision was introduced by Sylla and Lacy in 2010, it has become more popular among colorectal surgeons. However, some surgeons hesitate to use it, because this novel approach differs greatly from laparoscopic total mesorectal excision and requires a long learning curve. OBJECTIVE: This study analyzed the learning curve of transanal total mesorectal excision procedure and compared the different phases of transanal total mesorectal excision with laparoscopic total mesorectal excision. DESIGN: This is retrospective case-control study. SETTINGS: We used data from the approved colorectal cancer database of the Sixth Affiliated Hospital of Sun Yat-sen University. PATIENTS: The patients involved in this study underwent transanal total mesorectal excision performed by a single surgeon (L.K.) or underwent laparoscopic transanal total mesorectal excision performed by experienced surgeons. INTERVENTIONS: Transanal or laparoscopic resection of mid-low rectal cancer was conducted. MAIN OUTCOMES MEASURES: Perioperative complication and resection margin were measured. RESULTS: A total of 342 patients were included in both groups. The learning curve of transanal total mesorectal excision was divided into 3 phases. Data show that demographics and tumor characteristics were not significantly different between the matched groups. Indeed, during phase 1, only operative time was longer than in the laparoscopic group, whereas, during phase 2, results from the transanal group were comparable with the laparoscopic group. Results show that, during phase 3, operative time, intraoperative blood loss, and postoperative hospital stay were all lower than in the laparoscopic group. Local recurrence occurred in 3 patients during phase 1 and in 1 patient during phase 2. LIMITATIONS: This study was a small retrospective study and focused on just 1 surgeon performing transanal total mesorectal excision. CONCLUSIONS: Short-term and histopathologic outcomes are similar compared between a transanal group and matched laparoscopic group. Transanal total mesorectal excision also provided good oncologic outcomes. See Video Abstract at http://links.lww.com/DCR/B450. ESCISIN MESORRECTAL TOTAL TRANSANAL EN EL CNCER DE RECTO MEDIOBAJO EVALUACIN DE LA CURVA DE APRENDIZAJE Y COMPARACIN DE RESULTADOS A CORTO PLAZO CON TME LAPAROSCPICA ESTNDAR: ANTECEDENTES:Desde que Sylla y Lacy introdujeron la escisión mesorrectal total transanal en 2010, se ha vuelto más popular entre los cirujanos colorrectales. Sin embargo, algunos cirujanos dudan en utilizarlo, porque este nuevo método difiere mucho de la escisión mesorrectal total laparoscópica y requiere una larga curva de aprendizaje.OBJETIVO:Este estudio analizó la curva de aprendizaje del procedimiento de escisión mesorrectal total transanal y comparó las diferentes fases de la escisión mesorrectal total transanal con la escisión mesorrectal total laparoscópica.DISEÑO:Este es un estudio retrospectivo de casos y controles.ENTORNO CLINICO:Utilizamos base de datos de cáncer colorrectal aprobada del Sexto Hospital Afiliado de la Universidad Sun Yat-sen (Guangzhou, China).PACIENTES:Los pacientes involucrados en este estudio fueron sometidos a escisión mesorrectal total transanal realizada por un solo cirujano (LK) o se sometieron a escisión mesorrectal total transanal laparoscópica realizada por cirujanos experimentados.INTERVENCIONES:Resección transanal o laparoscópica de cáncer de recto medio-bajo.PRINCIPALES MEDIDAS DE VOLARCION:complicación perioperatoria y margen de resección.RESULTADOS:Se incluyó un total de 342 pacientes en ambos grupos. La curva de aprendizaje de la escisión mesorrectal total transanal se dividió en tres fases. Los datos muestran que las características demográficas y tumorales no fueron significativamente diferentes entre los grupos emparejados. De hecho, durante la fase 1, solo el tiempo operatorio fue más largo que en el grupo laparoscópico. Mientras que durante la fase 2, los resultados del grupo transanal fueron comparables a los del grupo laparoscópico. Los resultados muestran que durante la fase 3, el tiempo operatorio, la pérdida de sangre intraoperatoria y la estancia hospitalaria postoperatoria fueron menores que en el grupo laparoscópico. La recurrencia local ocurrió en 3 pacientes durante la fase 1 y en 1 paciente durante la fase 2.LIMITACIONES:Este estudio fue un estudio retrospectivo pequeño y se centró en un solo cirujano que realizaba la escisión mesorrectal total transanal.CONCLUSIÓN:Los resultados a corto plazo e histopatológicos son similares en comparación entre el grupo transanal y el grupo laparoscópico emparejado. La escisión mesorrectal total transanal también proporcionó buenos resultados oncológicos. Consulte Video Resumen en http://links.lww.com/DCR/B450.