Neoadjuvant botensilimab plus balstilimab response pattern in locally advanced mismatch repair proficient colorectal cancer.

In patients with locally advanced cancer without distant metastases, the neoadjuvant setting presents a platform to evaluate new drugs. For mismatch repair proficient/microsatellite stable (pMMR/MSS) colon and rectal cancer, immunotherapy has shown limited efficacy. Herein, we report exceptional responses observed with neoadjuvant botensilimab (BOT), an Fc-enhanced next-generation anti-CTLA-4 antibody, alongside balstilimab (BAL; an anti-PD-1 antibody) in two patients with pMMR/MSS colon and rectal cancer. The histological pattern of rapid immune response observed ("inside-out" (serosa-to-mucosa) tumor regression) has not been described previously in this setting. Spatial biology analyses (RareCyte Inc.) reveal mechanisms of actions of BOT, a novel innate-adaptive immune activator. These observations have downstream implications for clinical trial designs using neoadjuvant immunotherapy and potentially sparing patients chemotherapy.

Multidisciplinary Management of Cutaneous Gluteus Vaginal Fistula After Sacrospinous Ligament Fixation.

Introduction: Cutaneous gluteal vaginal fistula is a rare but significant postoperative complication which may present years after sacrospinous ligament fixation (SSLF) surgery There is limited data on the management of cutaneous vaginal fistula following SSLF. Case description: This case report describes a 77-year-old who presents twenty years after SSLF with cutaneous gluteal vaginal abscess and fistula. She underwent successful management with CT-guided percutaneous drainage of gluteal abscess and placement of guiding cutaneous vaginal catheter, laparoscopic pelvic wall dissection and evaluation, and transvaginal localization and removal of the infected permanent suture. Discussion: Multi-disciplinary approach should be considered in the treatment of chronic fistula status post SSLF, including interventional radiology, urogynecology, and minimally invasive gynecologic surgery.

Deficient E-cadherin adhesion in C57BL/6J-Min/+ mice is associated with increased tyrosine kinase activity and RhoA-dependent actomyosin contractility.

The Min/+ mouse is a model for APC-dependent colorectal cancer (CRC). We showed that tumorigenesis in this animal was associated with decreased E-cadherin adhesion and increased epidermal growth factor receptor (Egfr) activity in the non-tumor intestinal mucosa. Here, we tested whether these abnormalities correlated with changes in the actin cytoskeleton due to increased Rho-ROCK signaling. We treated Apc+/+ (WT) littermate small intestine with EGTA, an inhibitor of E-cadherin, and with LPA, an RhoA activator; both induced effects on adhesion and kinase activity that mimicked the Min/+ phenotype. GTP-bound Rho was increased in Min/+ enterocytes relative to WT. Since RhoA activity is associated with actomyosin contractility, markers of this signaling cascade were assessed including phosphorylated myosin light chain (MLC), cofilin, Pyk2, Src, and MAPK kinases. The increased actomyosin contractility characterizing Min/+ intestinal tissue was suppressed by the ROCK inhibitor, Y27632, but was inducible in the WT by EGTA or LPA. Finally, ultrastructural imaging revealed changes consistent with actomyosin contractility in Min/+ enterocytes. Thus, the positive regulation of E-cadherin adhesion provided by Apc+ in vivo allows proper negative regulation of Egfr, Src, Pyk2, and MAPK, as well as RhoA activities.

Apc deficiency is associated with increased Egfr activity in the intestinal enterocytes and adenomas of C57BL/6J-Min/+ mice.

Overexpression of the epidermal growth factor receptor (EGFR) and its increased tyrosine kinase activity are implicated in colorectal cancer (CRC) development and malignant progression. The C57BL/6J-Min/+ (Min/+) mouse is a model for CRC and develops numerous intestinal adenomas. We analyzed the normal mucosa of Min/+ and Apc+/+ (WT) littermate mice together with Apc-null adenomas to gain insight into the roles of Egfr in these intestinal tissues. Protein analyses showed that Egfr activity was highest in the tumors, and also up-regulated in Min/+ relative to WT enterocytes. Expression of ubiquitylated Egfr (Egfr-Ub) was increased in Min/+ enterocytes and tumors. Tumors exhibited increased association of Egfr with clathrin heavy chain (CHC), Gab1, and p85alpha, the regulatory subunit of phosphoinositide 3-kinase (PI3K), and tumors also overexpressed c-Src, PDK1, and Akt. Immunohistochemistry for Akt-p-Ser473 revealed a low level of this active kinase in Min/+ and WT enterocytes and its strong presence in tumors. Prostaglandin E2 (PGE2) is a product of cyclooxygenase-2 (Cox-2) activity that is up-regulated in Min/+ tumors and transactivates Egfr. PGE2 expression was significantly higher in untreated Min/+ tumors and reduced by treatment with the Cox-2 inhibitor, celecoxib. Dietary administration of this NSAID also inhibited Egfr activity in tumors. Increased activation of the EGFR-PI3K-Akt signaling pathway in tumors relative to Apc+/+ and ApcMin/+ enterocytes provides potential opportunities for therapeutic interventions to differentially suppress tumor formation, promotion, progression, and/or recurrence.

Adenomatous polyposis coli truncation alters cytoskeletal structure and microtubule stability in early intestinal tumorigenesis.

Partial loss of function of adenomatous polyposis coli (APC) protein by truncation of its carboxy (C)-terminus is an early factor in the development of many sporadic colorectal cancers. In the C57BL/6J Min/+ (Min/+) mouse, an animal with a germline mutation of Apc, we found that APC truncation was associated with reduced enterocyte migration and loss of association and membrane expression of adherens junction proteins. We hypothesized that these defects were related to changes in cytoskeletal function resulting from truncation of the APC C-terminus, which contains microtubule binding regions, as well as putative sites for indirect actin binding. We investigated this further by determining whether APC truncation produced in vivo changes in actin cytoskeletal structure and microtubule stability. The actin cytoskeleton of histologically normal enterocytes from Min/+ mice was compared to that of Apc+/+ (wild-type) mice by confocal indirect immunofluorescence microscopy. We found a significant loss of actin localization at the apical plasma membrane in Min/+ enterocytes. In addition, immunoblotting revealed increased levels of both unstable Tyr-tubulin and alpha-tubulin turnover in Min/+ enterocytes, indicating an alteration in microtubule dynamics. These studies suggest that loss of actin localization and changes in microtubule dynamics may be dominant negative effects of truncated APC. These changes are consistent with the defects in enterocyte migration and junctional complex formation observed in the Min/+ model of early APC-associated colorectal tumorigenesis.