Comparison of laparoscopic and open surgery for colorectal malignancy in obese patients: a propensity score-weighted cohort study.

BACKGROUND: Insufficient evidence exists to ascertain the long-term prognosis in patients with obesity undergoing laparoscopic surgery versus open surgery for colorectal cancer. METHODS: Employing an institutional database from 2009 to 2019, we assessed individuals with a body mass index of ≥30 kg/m2 who underwent surgery for primary stage I-III colorectal adenocarcinoma. We used propensity score-weighted analysis to compare short-term and oncologic outcomes between laparoscopic and open surgical approaches. RESULTS: This study enrolled 473 patients (open vs. laparoscopic surgery: 220 vs. 253; median follow-up period, 60 mo). The laparoscopy group showed a significantly longer operative time (252 vs. 212 min), a higher anastomotic-leakage rate (5.14% vs. 0.91%), and a greater proportion of Clavien-Dindo class > III complications (5.93% vs. 1.82%). The open group showed a higher wound infection rate (7.27% vs. 3.16%) and a higher readmission rate (6.36% vs. 2.37%). After propensity-score weighting, laparoscopy was inferior to open surgery in terms of long-term overall survival (hazard ratio: 1.43), disease-free survival (1.39), and recurrence rate (21.1% vs. 14.5%). In the subgroup analysis, female patients, older individuals, stage III patients, patients with rectal cancer, and those who underwent surgery after 2014 showed inferior long-term outcomes after laparoscopy. CONCLUSIONS: Laparoscopic colorectal cancer surgery for patients with obesity requires significant caution. Despite good short-term outcomes, this procedure is associated with hidden risks and poor long-term prognoses. In female patients, older individuals, stage III patients, patients with rectal cancer, and those treated in the late surgery era subgroups, caution is advised when performing laparoscopic surgery.

The oncologic outcome and prognostic factors for solitary colorectal liver metastasis after liver resection.

BACKGROUND: Studies on prognostic factors for patients undergoing surgery to treat solitary liver metastases originating from colorectal cancer (CRC) are limited. This study aimed to analyze significant prognostic factors associated with tumor recurrence and long-term survival after liver resection for solitary colorectal liver metastasis. METHODS: Data from 230 patients with solitary liver metastases from CRC who received liver resection between 2010 and 2019 were retrospectively analyzed. Recurrence-free survival (RFS) and overall survival (OS) were accessed with the Kaplan-Meier method and log-rank test. Cox regression multivariate analysis identified independent variables associated with RFS and OS. Nomograms were developed to predict patient outcomes after surgery. RESULTS: The 3- and 5-year OS rates were 72.3% and 59.8%, respectively. The 3- and 5-year RFS rates were 40.0% and 27.1%, respectively. Multivariate analysis revealed age ≥ 70 years, resection margin width < 10 mm, initial N2 stage, hypoalbuminemia before surgery, and neutrophil-to-lymphocyte ratio (NLR) ≥ 3 after surgery as independent prognostic factors for OS. For RFS, initial N2 stage, hypoalbuminemia before surgery, NLR ≥ 3 after surgery, elevated carcinoembryonic antigen (CEA) levels after surgery, and CEA ratio (after/before liver resection) < 0.3 were identified as independent prognostic factors. CONCLUSION: This study demonstrated that initial N2 stage, hypoalbuminemia before liver resection, and NLR ≥ 3 after liver resection exert a significant association on the RFS and OS of patients undergoing surgery for solitary liver metastases from CRC. Thus, upfront chemotherapy, prompt postoperative chemotherapy, and intensive postoperative surveillance are mandatory for patients having these adverse factors.

Using oral tegafur/uracil (UFT) plus leucovorin as adjuvant chemotherapy in stage II colorectal cancer: a propensity score matching study from Taiwan.

BACKGROUND: Early-stage colorectal cancer had excellent outcomes after curative resection, typically. However, a perplexing survival paradox between stage II and stage III was noted. This paradox could be influenced by the administration of routine postoperative adjuvant chemotherapy and the presence of high-risk factors in stage II CRC. The objective of the study was to investigate the influence of high-risk factors on patients with stage II CRC and assess the efficacy of oral tegafur/uracil (UFT) plus leucovorin as adjuvant chemotherapy for stage II CRC patients. METHODS: A retrospective study was conducted using propensity score matching at a single medical institution. A total of 1544 patients with stage II colorectal cancer who underwent radical surgery between January 2004 and January 2009 were included. The intervention used was tegafur/uracil plus leucovorin as adjuvant chemotherapy. The main outcome measures were disease-free survival and overall survival. RESULTS: After propensity score matching, 261 patients were included in three groups: no-treatment, half-year treatment, and one-year treatment. The clinical characteristics of each group tended to be more consistent. The Cox proportional hazard models showed that tegafur/uracil treatment or not was a significant independent factor for oncological outcome. Kaplan-Meier analysis also showed significantly better disease-free survival and overall survival. Further investigation revealed that tegafur/uracil duration was an independent factor for oncological outcome. While the survival curve did not reach statistical significance, the one-year UFT treatment group demonstrated the best treatment trend. CONCLUSIONS: This study suggests that tegafur/uracil plus leucovorin is a feasible adjuvant chemotherapy regimen for patients with stage II colorectal cancer after curative surgical treatment. Prolonged tegafur/uracil plus leucovorin treatment for 12 months showed a trend towards better outcomes in patients with stage II colorectal cancer.

Effect of short-course radiotherapy followed by oxaliplatin-based consolidation chemotherapy on organ preservation in locally advanced rectal cancer.

PURPOSE: We analyzed the effectiveness, safety, and mid-term oncological outcomes of short-course radiotherapy (SCRT) and oxaliplatin-based consolidation chemotherapy in patients with locally advanced rectal cancer (LARC). METHODS: We retrospectively evaluated 64 patients with LARC who underwent SCRT and tegafox (tegafur-uracil/leucovorin plus oxaliplatin) or mFOLFOX-6 (5-fluorouracil, leucovorin, and oxaliplatin) consolidation chemotherapy before surgery between January 2015 and December 2020. Tumor response, patient compliance, toxicity, surgical outcomes, overall survival (OS), and disease-free survival (DFS) were analyzed. RESULTS: Sixty-four patients with a mean age of 58.67 years (44 males) were included; 48 (75%) had tumors within 5 cm of the anal verge. Additionally, 93.8% of the patients underwent at least 2 months of chemotherapy, and three required dose reduction. Grade III toxicity occurred in 2 patients, and 10 had a clinical complete response and opted for non-operative management. One patient experienced tumor progression and underwent further treatment without surgery. Among the 53 patients who underwent surgery, 51 (96.2%) had sphincter preservation, 3 had Clavien-Dindo grade III complications, and no mortality occurred. The complete response rate for the entire cohort was 23.4%. Moreover, 47 patients (74.6%) had a neoadjuvant rectal score of < 16 after treatment. After a median follow-up time of 32.01 months, 6 (9.3%) had local recurrence, and 17 (26.6%) had distant metastasis. The 3-year OS, DFS and stoma-free rates were 89.5%, 65.5%, and 78.1% respectively. CONCLUSION: SCRT followed by oxaliplatin-based consolidation chemotherapy is safe and effective for tumor downstaging in LARC, further improving the sphincter preservation rate.

Transanal Total Mesorectal Excision (TaTME) versus Laparoscopic Total Mesorectal Excision for Lower Rectal Cancer: A Propensity Score-Matched Analysis.

Studies have reported positive short-term and histopathological results of transanal total mesorectal excision (TaTME) for mid-low rectal cancer. The long-term oncological outcomes are diverse, and concerns regarding the high local recurrence (LR) rate of TaTME have recently increased. We retrospectively analyzed 298 consecutive patients who underwent Laparoscopic TME (LapTME) or TaTME between January 2015 and December 2019. Propensity score-matching (PSM) was performed with patients matched for demographics and stage. After PSM, 63 patients were included in each group. The TaTME group had a longer mean operative time (394 vs. 333 min, p < 0.001). The blood loss, diverting stoma rate, and conversion rate were similar. Postoperatively, TaTME and LapTME had compatible complications, recovery, and hospital stay. A similar specimen quality was detected in both groups. After a mean follow-up period of 41−47 months, TaTME had less LR than LapTME (9.5% vs. 23.8%, p = 0.031). The 3-year overall survival was 80.3% in the TaTME group and 73.6% in the LapTME group (p = 0.331). The 3-year disease-free survival (DFS) rate was 72.0% in the TaTME group and 56.6% in the LapTME group (p = 0.038). In conclusion, better DFS and fewer LR events were observed after TaTME; thus, TaTME can be considered a safe and feasible approach in patients with low rectal cancer.

Usefulness of close surveillance for rectal cancer patients after neoadjuvant chemoradiotherapy.

It is controversial whether patients who achieve clinical complete remission (cCR) of rectal cancer should be treated with the "watch and wait" (W&W) or radical resection (RR) strategy. Our study aimed to compare the survival outcomes and ostomy rate of the W&W and RR strategies. Between January 2008 and December 2015, we investigated 26 patients who achieved pathologic complete remission after undergoing RR and 36 patients who adopted the W&W strategy because of cCR. The tumor regrowth, salvage surgery, recurrence, disease-free, and overall survival (OS) rates were assessed. In our study, recurrences occurred in nine and two patients from the W&W and RR groups, respectively. Each patient in the RR group had a temporary or permanent ostomy, but only three (8.3%) had an ostomy in the W&W group. The 5-year recurrence rate was 25.0% in the W&W group and 7.7% in the RR group. Six patients (16.7%) had tumor regrowth in the W&W group, and all were resectable when regrowth. The 5-year OS rates between the two groups were nonsignificant. There is no specific risk factor for recurrence and OS. Under close surveillance, the W&W group achieved similar OS to the RR group and benefited from a lower ostomy rate.

Tegafur-Uracil/Leucovorin Plus Oxaliplatin (TEGAFOX) as Consolidation Regimen after Short-Course Radiotherapy Is Effective for Locally Advanced Rectal Cancer.

This study aimed to explore the safety and efficacy of neoadjuvant SCRT and tegafur−uracil/leucovorin plus oxaliplatin (TEGAFOX) for LARC in comparison to those of the modified 5-fluorouracil, leucovorin, and oxaliplatin (mFOLFOX-6) regimen. We retrospectively evaluated 15 and 22 patients with LARC who underwent SCRT, followed by consolidation chemotherapy with TEGAFOX and mFOLFOX-6 before surgery, respectively, between January 2015 and December 2019. The primary endpoint was the tumor response rate. The secondary endpoints were compliance, toxicity, complications, overall survival (OS), and disease-free survival (DFS). The dose reduction rate was lower in the TEGAFOX group (0 vs. 9.1% (n = 2)). No grade III-IV toxicities occurred in the TEGAFOX group. Two and four patients in the TEGAFOX and mFOLFOX-6 groups, respectively, achieved clinical complete responses. The pathologic complete response rate was lower in the TEGAFOX group (7.7% vs. 17.6%). Overall, 11 (73.3%) and 17 (81.0%) patients had a neoadjuvant rectal (NAR) score of <16 in the TEGAFOX and mFOLFOX-6 groups, respectively. All patients in this study received sphincter-preservation surgery. One patient in each group developed Clavien−Dindo grade III complications. There were no significant between-group differences in the 3-year OS (81.8% vs. 84.8%, p = 0.884) and 3-year DFS (72% vs. 71.6%, p = 0.824) rates. TEGAFOX, as consolidation chemotherapy after SCRT, achieves good tumor downstaging and patient compliance in LARC. The toxicity, complications, and surgical outcomes are similar to those of mFOLFOX-6. Thus, TEGAFOX can be considered a chemotherapy option for rectal cancer treatment.

Neoadjuvant Short-Course Radiotherapy Followed by Consolidation Chemotherapy before Surgery for Treating Locally Advanced Rectal Cancer: A Systematic Review and Meta-Analysis.

Neoadjuvant short course radiotherapy (SCRT) followed by consolidation chemotherapy (CCT) is an alternative treatment for locally advanced rectal cancer (LARC). We performed this systematic review and meta-analysis to explore the tumor response and oncological outcomes of this new approach compared to conventional chemoradiotherapy (CRT). An online search of the PubMed, Embase, and Cochrane Library databases was performed. This review included 7507 patients from 14 different cohorts. The pCR rate was higher with SCRT + CCT than that with CRT (RR: 1.60; 95% CI: 1.35−1.91; p < 0.01). SCRT + CCT provided a higher ypN0 response (RR: 1.06; 95% CI: 1.01−1.12; p = 0.02). There were no differences in R0 resection and positive CRM rates; however, more sphincter-preservation surgeries were performed in the SCRT + CCT arm (RR: 1.06; 95% CI: 1.01−1.11; p = 0.02). There was no difference in the OS and DFS between the SCRT + CCT and the CRT arms (OS: HR: 0.85, p = 0.07; DFS: HR: 0.88, p = 0.08). The compliance and toxicity were comparable between the SCRT and CRT groups. In the subgroup analysis, patients who underwent four or more cycles of CCT had better pCR and DFS events. Therefore, SCRT followed by consolidation chemotherapy might be an effective alternative treatment for LARC.

Pretreatment Nutrition-Inflammation Biomarkers Correlated with Differential Cytokine Profiles in Taiwanese Patients with Colorectal Cancer.

Systemic inflammation plays a pivotal role in colorectal cancer (CRC) development. Two hallmarks reflect the severity of inflammation-circulating cytokines and nutrition-inflammation biomarkers (NIBs); however, their interplay has not been fully investigated. In total, 128 CRC patients were included. Ten circulating cytokines (TNF-α, TGF-ß, IFN-γ, IL-1ß, IL-4, IL-6, IL-10, IL-12, IL-13, and IL-23) and NIBs were analyzed. The relationship between cytokines, NIBs, clinicopathological variables, and overall survival (OS) was assessed using univariate and multivariate analyses. Three NIBs (CRP-to-albumin ratio [CAR]), neutrophil-to-lymphocyte ratio [NLR]), and prognostic nutritional index [PNI]) were associated with OS in univariate analysis; however, CAR was better for OS prediction in multivariate analysis (P = 0.015). None of the serum cytokines analyzed showed a significant association with OS. High CAR (≥0.25) and high IL-10 (≥76.6 pg/mL), high NLR (≥8.2) and high IL-23 (≥51.2 pg/mL), and high PNI (≥42.4) and high IL-1ß (≥14.3 pg/mL) values were correlated. CAR, NLR, and PNI were not correlated with each other, whereas circulating cytokines were closely interrelated. High CAR was an independent predictor of poor OS in patients with CRC. Different NIBs have unique cytokine profiles, but show no correlation with each other. There is a close association among the circulating cytokines.

Advantage of laparoscopic surgery in patients with generalized obesity operated for colorectal malignancy: A retrospective cohort study.

Background: Because of the progression of minimally invasive surgery skills and obesity in colorectal surgery, we aimed to evaluate the short-term outcomes of colorectal cancer resections in patients with generalized obesity at a single teaching hospital with mature surgical techniques and training programs. Methods: A total of 537 patients were diagnosed with CRC and had a body mass index ≥30 kg/m2 between January 2009 and December 2019 at a single institution. 265 patients underwent open surgery and 272 patients underwent laparoscopic surgery. Data were analysed to explore the independent risk factors for postoperative complications. Results: The laparoscopic group had less blood loss (73 ± 128 vs. 148 ± 290 ml, p < 0.001) and a shorter postoperative hospital stay (10.8 ± 17.1 vs. 11.7 ± 6.8 days, p < 0.001) than the open group. The number of harvested lymph nodes did not significantly differ between the two groups (30.9 ± 18.3 vs. 30.2 ± 15.3, p = 0.981). Although anastomotic leakage was significantly higher in the laparoscopic group (1.5% vs. 4.8%, p = 0.030), there were also similar overall postoperative morbidity and mortality rates between the open and laparoscopic groups for CRC patients with generalized obesity who underwent surgery. Conclusion: Laparoscopic surgery can reduce blood loss, decrease the length of hospital stay, obtain a similar number of harvested lymph nodes, and achieve an acceptable conversion rate for CRC patients with generalized obesity. We suggest that laparoscopic surgery could become a standard method for CRC treatment in patients with generalized obesity.

The Clinical Utility of the Geriatric Nutritional Risk Index in Predicting Postoperative Complications and Long-Term Survival in Elderly Patients with Colorectal Cancer after Curative Surgery.

Research on the relationship between the geriatric nutritional risk index (GNRI) and postoperative complications/oncological outcomes in elderly colorectal cancer (CRC) patients is limited. This study investigated the prognostic value of the GNRI in aged CRC patients. We retrospectively analyzed 1206 consecutive CRC patients aged over 75 years who underwent curative-intent surgery from January 2008 to December 2015 and categorized them into high GNRI (≥98) and low GNRI (<98) groups according to a receiver operating characteristic (ROC) curve analysis. Uni- and multivariate logistic regression analysis were used to explore the association of the GNRI with postoperative complications. Kaplan-Meier survival analyses and the Cox proportional hazard model were used to explore the association between GNRI and survival. We discovered that GNRI is an independent risk factor for postoperative complications (HR: 1.774, p = 0.037). Surgical site infection, wound dehiscence and pneumonia were more common in patients with GNRI < 98. Survival analysis showed significantly worse overall survival and disease-free survival in the low GNRI group (both p < 0.001). In the multivariate analysis, GNRI < 98 was an independent risk factor for OS (HR: 1.329, p = 0.031) and DFS (HR: 1.312, p = 0.034). Thus, preoperative GNRI can be effectively used to predict postoperative complications and long-term survival in elderly CRC patients after curative surgery.

Correlation Between the Glasgow Prognostic Score and the Serum Cytokine Profile in Taiwanese Patients with Colorectal Cancer.

BACKGROUND: The Glasgow Prognostic Score and circulating cytokine levels are related to the prognosis of colorectal cancer and the severity of chronic inflammation. The association between the Glasgow Prognostic Score and circulating cytokines in colorectal cancer remains unclear. METHODS: The levels of 10 circulating cytokines (TNF-α, TGF-ß, IFN-γ, IL-1ß, IL-4, IL-6, IL-10, IL-12, IL-13, and IL-23) were measured in 128 patients with colorectal cancer. The relationship between the Glasgow Prognostic Score, clinicopathologic variables, and cytokine levels was assessed by univariate and multivariate logistic regression analyses. The correlation among cytokines was also examined. RESULTS: Patients with advanced stage colorectal cancer had lower levels of albumin (P = 0.003), higher levels of C-reactive protein (CRP; P < 0.001), carcinoembryonic antigen (CEA; P < 0.001), interferon (IFN)-γ (P < 0.001), and interleukin (IL)-10 (P = 0.006), and shorter survival outcomes (P < 0.001). Patients with a high Glasgow Prognostic Score (1 or 2) had lower 5-year progression-free survival and poor overall survival (log-rank P < 0.001). A high Glasgow Prognostic Score was significantly correlated with abnormal CEA levels (CEA > 5 ng/mL, P = 0.033), and higher levels of tumor necrosis factor (TNF)-α (TNF-α ⩾ 53.9 pg/mL, P = 0.035) and IL-10 (IL-10 ⩾ 75.95 pg/mL, P = 0.008). TNF-α, IFN-γ, IL-1ß, IL-4, IL-6, IL-10, IL-13, and IL-23 were significantly correlated with each other (all P < 0.05). Only IL-10 was correlated with abnormal CEA levels (P < 0.001). CONCLUSION: The Glasgow Prognostic Score and level of circulating cytokines have an intergroup correlation, and there is a close association among cytokines in colorectal cancer.

Prognostic value of the C-reactive protein to albumin ratio in colorectal cancer: an updated systematic review and meta-analysis.

BACKGROUNDS: The inflammatory biomarker "C-reactive protein to albumin ratio (CAR)" has been reported to significantly correlate to a variety of human cancers. However, there are conflicting results regarding the prognostic value of CAR in colorectal cancer. Previous studies mainly assessed patients in Eastern countries, so their findings may not be applicable to the Western population. Therefore, this updated meta-analysis aimed to investigate the prognostic value of pre-treatment CAR and outcomes of patients with colorectal cancer. METHODS: We conducted a systematic search for eligible literature until October 31, 2020, using PubMed and Embase databases. Studies assessing pre-treatment CAR and outcomes of colorectal cancer were included. Outcome measures included overall survival, disease-free survival, progression-free survival, and clinicopathological features. The pooled hazard ratios (HR) with 95% confidence intervals (CI) were used as effective values. RESULTS: A total of 15 studies involving 6329 patients were included in this study. The pooled results indicated that a high pre-treatment CAR was associated with poor overall survival (HR 2.028, 95% CI 1.808-2.275, p < 0.001) and poor disease-free survival/progression-free survival (HR 1.768, 95% CI 1.321-2.365, p < 0.001). Subgroup analysis revealed a constant prognostic value of the pre-treatment CAR despite different study regions, sample size, cancer stage, treatment methods, or the cut-off value used. We also noted a correlation between high pre-treatment CAR and old age, male sex, colon cancer, advanced stage (III/IV), large tumor size, poor differentiation, elevated carcinoembryonic antigen levels, neutrophil-to-lymphocyte ratio, and the modified Glasgow prognostic score. CONCLUSIONS: High pre-treatment CAR was associated with poor overall survival, disease-free survival, and progression-free survival in colorectal cancer. It can serve as a prognostic marker for colorectal cancer in clinical practice.

Primary signet ring cell carcinoma of the cervix: A case report with review of the literature.

OBJECTIVE: Primary cervical signet ring cell carcinoma (PCSRCC) is extremely rare. In this paper, we describe a Case presenting with PCSRCC. CASE REPORT: The 48-year-old woman visited the gynecological department because of postmenopausal bleeding. A cervical mass was discovered through pelvic examination, and the biopsy results indicated a poorly differentiated adenocarcinoma with a signet ring cell pattern. Colonoscopy revealed external compression of the rectum without intraluminal mucosal lesions. Abdominal computed tomography revealed a suspicious malignant lesion at the cervicorectal junction and multiple metastases. Debulking surgery was performed and the final pathology report documented a FIGO stage IVb PCSRCC involving multiple sites. CONCLUSION: Complete tumor survey and staging are critical to differentiate primary from metastatic signet cell carcinoma of the cervix. Immunohistochemical studies cannot provide precise information. Because cases are rare, it is difficult to determine the proper treatment guidelines and prognosis.

Primary signet ring cell carcinoma of the cervix: A case report with review of the literature.

OBJECTIVE: Primary cervical signet ring cell carcinoma (PCSRCC) is extremely rare. In this paper, we describe a case presenting with PCSRCC. CASE REPORT: The 48-year-old woman visited the gynecological department because of postmenopausal bleeding. A cervical mass was discovered through pelvic examination, and the biopsy results indicated a poorly differentiated adenocarcinoma with a signet ring cell pattern. Colonoscopy revealed external compression of the rectum without intraluminal mucosal lesions. Abdominal computed tomography revealed a suspicious malignant lesion at the cervicorectal junction and multiple metastases. Debulking surgery was performed and the final pathology report documented a FIGO stage IVb PCSRCC involving multiple sites. CONCLUSION: Complete tumor survey and staging are critical to differentiate primary from metastatic signet cell carcinoma of the cervix. Immunohistochemical studies cannot provide precise information. Because cases are rare, it is difficult to determine the proper treatment guidelines and prognosis.

Colonoscopy-induced right superior rectal artery tear: A case report.

INTRODUCTION: Colonoscopy is a well-accepted procedure applied worldwide in diagnosis and management of colon lesions. The incidence of reported complications is not rare. PRESENTATION: A 79-year-old man with postcolonoscopy intraperitoneal bleeding secondary to superior rectal artery injury. He received computer tomogram and angiogram study to confirmed bleeder from right superior rectal artery and subsequently managed with embolization and operation. DISCUSSION: This is the second case report in the literatures of mesentery tear and the first case with massive hemoperitoneum. CONCLUSION: Identification and careful evaluation are crucial for successful diagnosis and treatment in cases such as this after colonoscopy.

Scaffolding protein Homer 1c mediates hypertrophic responses downstream of Gq in cardiomyocytes.

Activation of the heterotrimeric G protein, Gq, causes cardiomyocyte hypertrophy in vivo and in cell models. Responses to activated Gq in cardiomyocytes are mediated exclusively by phospholipase Cß1b (PLCß1b), because it localizes at the sarcolemma by binding to Shank3, a high-molecular-weight (MW) scaffolding protein. Shank3 can bind to the Homer family of low-MW scaffolding proteins that fine tune Ca(2+) signaling by facilitating crosstalk between Ca(2+) channels at the cell surface with those on intracellular Ca(2+) stores. Activation of α(1)-adrenergic receptors, expression of constitutively active Gαq (GαqQL), or PLCß1b initiated cardiomyocyte hypertrophy and increased Homer 1c mRNA expression, by 1.6 ± 0.18-, 1.9 ± 0.17-, and 1.5 ± 0.07-fold, respectively (means ± se, 6 independent experiments, P<0.05). Expression of Homer 1c induced an increase in cardiomyocyte area from 853 ± 27 to 1146 ± 31 µm(2) (P<0.05); furthermore, expression of dominant-negative Homer (Homer 1a) reversed the increase in cell size caused by α(1)-adrenergic agonist or PLCß1b treatment (1503±48 to 996±28 and 1626±48 to 828±31 µm(2), respectively, P<0.05). Homer proteins were localized near the sarcolemma, associated with Shank3 and phospholipase Cß1b. We conclude that Gq-mediated hypertrophy involves activation of PLCß1b scaffolded onto a Shank3/Homer complex. Signaling downstream of Homer 1c is necessary and sufficient for Gq-initiated hypertrophy.

Phospholipase Cbeta1b associates with a Shank3 complex at the cardiac sarcolemma.

Activation of the heterotrimeric G protein Gq causes cardiomyocyte hypertrophy in vivo and in cell models. Our previous studies have shown that responses to activated Gq in cardiomyocytes are mediated exclusively by phospholipase Cß1b (PLCß1b), because only this PLCß subtype localizes at the cardiac sarcolemma. In the current study, we investigated the proteins involved in targeting PLCß1b to the sarcolemma in neonatal rat cardiomyocytes. PLCß1b, but not PLCß1a, coimmunoprecipitated with the high-MW scaffolding protein SH3 and ankyrin repeat protein 3 (Shank3), as well as the known Shank3-interacting protein α-fodrin. The 32-aa splice-variant-specific C-terminal tail of PLCß1b also associated with Shank3 and α-fodrin, indicating that PLCß1b binds via the C-terminal sequence. Shank3 colocalized with PLCß1b at the sarcolemma, and both proteins were enriched in the light membrane fractions. Knockdown of Shank3 using siRNA reduced PLC activation and downstream hypertrophic responses, demonstrating the importance of sarcolemmal localization for PLC signaling. These data indicate that PLCß1b associates with a Shank3 complex at the cardiac sarcolemma via its splice-variant-specific C-terminal tail. Sarcolemmmal localization is central to PLC activation and subsequent downstream signaling following Gq-coupled receptor activation.

Nonsense mediated decay resistant mutations are a source of expressed mutant proteins in colon cancer cell lines with microsatellite instability.

BACKGROUND: Frameshift mutations in microsatellite instability high (MSI-High) colorectal cancers are a potential source of targetable neo-antigens. Many nonsense transcripts are subject to rapid degradation due to nonsense-mediated decay (NMD), but nonsense transcripts with a cMS in the last exon or near the last exon-exon junction have intrinsic resistance to nonsense-mediated decay (NMD). NMD-resistant transcripts are therefore a likely source of expressed mutant proteins in MSI-High tumours. METHODS: Using antibodies to the conserved N-termini of predicted mutant proteins, we analysed MSI-High colorectal cancer cell lines for examples of naturally expressed mutant proteins arising from frameshift mutations in coding microsatellites (cMS) by immunoprecipitation and Western Blot experiments. Detected mutant protein bands from NMD-resistant transcripts were further validated by gene-specific short-interfering RNA (siRNA) knockdown. A genome-wide search was performed to identify cMS-containing genes likely to generate NMD-resistant transcripts that could encode for antigenic expressed mutant proteins in MSI-High colon cancers. These genes were screened for cMS mutations in the MSI-High colon cancer cell lines. RESULTS: Mutant protein bands of expected molecular weight were detected in mutated MSI-High cell lines for NMD-resistant transcripts (CREBBP, EP300, TTK), but not NMD-sensitive transcripts (BAX, CASP5, MSH3). Expression of the mutant CREBBP and EP300 proteins was confirmed by siRNA knockdown. Five cMS-bearing genes identified from the genome-wide search and without existing mutation data (SFRS12IP1, MED8, ASXL1, FBXL3 and RGS12) were found to be mutated in at least 5 of 11 (45%) of the MSI-High cell lines tested. CONCLUSION: NMD-resistant transcripts can give rise to expressed mutant proteins in MSI-High colon cancer cells. If commonly expressed in primary MSI-High colon cancers, MSI-derived mutant proteins could be useful as cancer specific immunological targets in a vaccine targeting MSI-High colonic tumours.