Renal medullary carcinoma (RMC) is a rare renal malignancy that has been associated with sickle hemoglobinopathies. RMC is aggressive, difficult to treat, and occurs primarily in adolescents and ...young adults of African ancestry. This cancer is driven by the loss of SMARCB1, a tumor suppressor seen in a number of primarily rare childhood cancers (e.g., rhabdoid tumor of the kidney and atypical teratoid rhabdoid tumor). Treatment options remain limited due in part to the limited knowledge of RMC biology. However, significant advances have been made in unraveling the biology of RMC, from genomics to therapeutic targets, over the past 5 years. In this review, we will present these advances and discuss what new questions exist in the field.
SMARCB1 is a critical component of the BAF complex that is responsible for global chromatin remodeling. Loss of SMARCB1 has been implicated in the initiation of cancers such as malignant rhabdoid ...tumor (MRT), atypical teratoid rhabdoid tumor (ATRT), and, more recently, renal medullary carcinoma (RMC). These SMARCB1-deficient tumors have remarkably stable genomes, offering unique insights into the epigenetic mechanisms in cancer biology. Given the lack of druggable targets and the high mortality associated with SMARCB1-deficient tumors, a significant research effort has been directed toward understanding the mechanisms of tumor transformation and proliferation. Accumulating evidence suggests that tumorigenicity arises from aberrant enhancer and promoter regulation followed by dysfunctional transcriptional control. In this review, we outline key mechanisms by which loss of SMARCB1 may lead to tumor formation and cover how these mechanisms have been used for the design of targeted therapy.
p.G12C mutation occurs in approximately 1 to 2% of pancreatic cancers. The safety and efficacy of sotorasib, a KRAS G12C inhibitor, in previously treated patients with
p.G12C-mutated pancreatic ...cancer are unknown.
We conducted a single-group, phase 1-2 trial to assess the safety and efficacy of sotorasib treatment in patients with
p.G12C-mutated pancreatic cancer who had received at least one previous systemic therapy. The primary objective of phase 1 was to assess safety and to identify the recommended dose for phase 2. In phase 2, patients received sotorasib at a dose of 960 mg orally once daily. The primary end point for phase 2 was a centrally confirmed objective response (defined as a complete or partial response). Efficacy end points were assessed in the pooled population from both phases and included objective response, duration of response, time to objective response, disease control (defined as an objective response or stable disease), progression-free survival, and overall survival. Safety was also assessed.
The pooled population from phases 1 and 2 consisted of 38 patients, all of whom had metastatic disease at enrollment and had previously received chemotherapy. At baseline, patients had received a median of 2 lines (range, 1 to 8) of therapy previously. All 38 patients received sotorasib in the trial. A total of 8 patients had a centrally confirmed objective response (21%; 95% confidence interval CI, 10 to 37). The median progression-free survival was 4.0 months (95% CI, 2.8 to 5.6), and the median overall survival was 6.9 months (95% CI, 5.0 to 9.1). Treatment-related adverse events of any grade were reported in 16 patients (42%); 6 patients (16%) had grade 3 adverse events. No treatment-related adverse events were fatal or led to treatment discontinuation.
Sotorasib showed anticancer activity and had an acceptable safety profile in patients with
p.G12C-mutated advanced pancreatic cancer who had received previous treatment. (Funded by Amgen and others; CodeBreaK 100 ClinicalTrials.gov number, NCT03600883.).
Increasing evidence has supported the important role of mesenchymal stem cells (MSCs) in wound healing, however, the underlying mechanism remains unclear. Recently, we have isolated a unique ...population of MSCs from human gingiva (GMSCs) with similar stem cell-like properties, immunosuppressive, and anti-inflammatory functions as human bone marrow-derived MSCs (BMSCs). We describe here the interplay between GMSCs and macrophages and the potential relevance in skin wound healing. When cocultured with GMSCs, macrophages acquired an anti-inflammatory M2 phenotype characterized by an increased expression of mannose receptor (MR; CD206) and secretory cytokines interleukin (IL)-10 and IL-6, a suppressed production of tumor necrosis factor (TNF)-α, and decreased ability to induce Th-17 cell expansion. In vivo, we demonstrated that systemically infused GMSCs could home to the wound site in a tight spatial interaction with host macrophages, promoted them toward M2 polarization, and significantly enhanced wound repair. Mechanistically, GMSC treatment mitigated local inflammation mediated by a suppressed infiltration of inflammatory cells and production of IL-6 and TNF-α, and an increased expression of IL-10. The GMSC-induced suppression of TNF-α secretion by macrophages appears to correlate with impaired activation of NFκB p50. These findings provide first evidence that GMSCs are capable to elicit M2 polarization of macrophages, which might contribute to a marked acceleration of wound healing.
On the basis of the ACCORD trial, FOLFIRINOX is effective in metastatic pancreatic adenocarcinoma (PDAC), making it a rational choice for locally advanced PDAC (LA). Aims of this study are to ...evaluate the accuracy of imaging in determining the resectability of PDAC and to determine the surgical and clinicopathologic outcomes of pancreatic resections after neoadjuvant FOLFIRINOX therapy.
Clinicopathologic data were retrospectively collected for surgical PDAC patients receiving neoadjuvant FOLFIRINOX or no neoadjuvant therapy between April 2011 and February 2014. Americas Hepato-Pancreato-Biliary Association/Society of Surgical Oncology/Society for Surgery of the Alimentary Tract consensus guidelines defined LA and borderline. Imaging was reviewed by a blinded senior pancreatic surgeon.
Of 188 patients undergoing resection for PDAC, 40 LA/borderline received FOLFIRINOX and 87 received no neoadjuvant therapy. FOLFIRINOX resulted in a significant decrease in tumor size, yet 19 patients were still classified as LA and 9 as borderline. Despite post-FOLFIRINOX imaging suggesting continued unresectability, 92% had an R0 resection. When compared with no neoadjuvant therapy, FOLFIRINOX resulted in significantly longer operative times (393 vs 300 minutes) and blood loss (600 vs 400 mL), but significantly lower operative morbidity (36% vs 63%) and no postoperative pancreatic fistulas. Length of stay (6 vs 7 days), readmissions (20% vs 30%), and mortality were equivalent (1% vs 0%). On final pathology, the FOLFIRINOX group had a significant decrease in lymph node positivity (35% vs 79%) and perineural invasion (72% vs 95%). Median follow-up was 11 months with a significant increase in overall survival with FOLFIRINOX.
After neoadjuvant FOLFIRINOX imaging no longer predicts unresectability. Traditional pathologic predictors of survival are improved, and morbidity is decreased in comparison to patients with clearly resectable cancers at the time of presentation.
Malignant rhabdoid tumors (MRT) are highly aggressive pediatric cancers that respond poorly to current therapies. In this study, we screened several MRT cell lines with large-scale RNAi, CRISPR-Cas9, ...and small-molecule libraries to identify potential drug targets specific for these cancers. We discovered
and
, the canonical negative regulators of p53, as significant vulnerabilities. Using two compounds currently in clinical development, idasanutlin (MDM2-specific) and ATSP-7041 (MDM2/4-dual), we show that MRT cells were more sensitive than other p53 wild-type cancer cell lines to inhibition of MDM2 alone as well as dual inhibition of MDM2/4. These compounds caused significant upregulation of the p53 pathway in MRT cells, and sensitivity was ablated by CRISPR-Cas9-mediated inactivation of
. We show that loss of SMARCB1, a subunit of the SWI/SNF (BAF) complex mutated in nearly all MRTs, sensitized cells to MDM2 and MDM2/4 inhibition by enhancing p53-mediated apoptosis. Both MDM2 and MDM2/4 inhibition slowed MRT xenograft growth
, with a 5-day idasanutlin pulse causing marked regression of all xenografts, including durable complete responses in 50% of mice. Together, these studies identify a genetic connection between mutations in the SWI/SNF chromatin-remodeling complex and the tumor suppressor gene
and provide preclinical evidence to support the targeting of MDM2 and MDM4 in this often-fatal pediatric cancer. SIGNIFICANCE: This study identifies two targets, MDM2 and MDM4, as vulnerabilities in a deadly pediatric cancer and provides preclinical evidence that compounds inhibiting these proteins have therapeutic potential.
Background
Anastomotic leakage is associated with high mortality, high reoperation rate, and increased hospital length of stay. Although many studies have examined the risk factors for anastomotic ...leak, large prospective series that report on long-term survival rates are lacking.
Methods
Data of 1576 patients who underwent primary resection and anastomosis for colorectal adenocarcinoma at a single institution from 1984 to 2004 were prospectively collected. Anastomotic leaks (LEK) were classified as radiological (RAD), local (LOC), or generalised (GEN). Logistic regression analysis of 21 variables was undertaken. Overall survival, cancer-related survival, and disease-free survival were analysed using the Kaplan-Meier method.
Results
Mean age of the patients was 67 years (SD = 12.5) and 834 (52.9%) were male. An LEK was more likely when relatively major gynaecological (tubo-oophorectomy,
P
= 0.004; hysterectomy,
P
= 0.006) or urological (total cystectomy,
P
= 0.014) procedures were performed during the same operative session. Other significant factors were anterior resection (
P
< 0.001), anastomosis using an intraluminal stapling device (
P
= 0.005), abdominal drain via laparoscopic port (
P
= 0.024), postoperative blood transfusion (
P
< 0.001), primary cancer site at the rectum (
P
= 0.016), and TNM stage of T2 or higher (
P
= 0.026). Having an LEK showed significant impact on overall (
P
= 0.021), cancer-related (
P
= 0.006), and disease-free (
P
= 0.001) survival.
Conclusion
In this prospective study, advanced tumour stage, distal site, and need for postoperative blood transfusion were associated with increased rates of anastomotic leakage. In addition to their high risk of immediate postoperative morbidity and mortality, both localized and generalized leaks had similarly negative impacts on overall, cancer-related, and disease-free survival.
Gastrointestinal mucosal injury (mucositis), commonly affecting the oral cavity, is a clinically significant yet incompletely understood complication of cancer chemotherapy. Although antineoplastic ...cytotoxicity constitutes the primary injury trigger, the interaction of oral microbial commensals with mucosal tissues could modify the response. It is not clear, however, whether chemotherapy and its associated treatments affect oral microbial communities disrupting the homeostatic balance between resident microorganisms and the adjacent mucosa and if such alterations are associated with mucositis. To gain knowledge on the pathophysiology of oral mucositis, 49 subjects receiving 5-fluorouracil (5-FU) or doxorubicin-based chemotherapy were evaluated longitudinally during one cycle, assessing clinical outcomes, bacterial and fungal oral microbiome changes, and epithelial transcriptome responses. As a control for microbiome stability, 30 non-cancer subjects were longitudinally assessed. Through complementary in vitro assays, we also evaluated the antibacterial potential of 5-FU on oral microorganisms and the interaction of commensals with oral epithelial tissues.
Oral mucositis severity was associated with 5-FU, increased salivary flow, and higher oral granulocyte counts. The oral bacteriome was disrupted during chemotherapy and while antibiotic and acid inhibitor intake contributed to these changes, bacteriome disruptions were also correlated with antineoplastics and independently and strongly associated with oral mucositis severity. Mucositis-associated bacteriome shifts included depletion of common health-associated commensals from the genera Streptococcus, Actinomyces, Gemella, Granulicatella, and Veillonella and enrichment of Gram-negative bacteria such as Fusobacterium nucleatum and Prevotella oris. Shifts could not be explained by a direct antibacterial effect of 5-FU, but rather resembled the inflammation-associated dysbiotic shifts seen in other oral conditions. Epithelial transcriptional responses during chemotherapy included upregulation of genes involved in innate immunity and apoptosis. Using a multilayer epithelial construct, we show mucositis-associated dysbiotic shifts may contribute to aggravate mucosal damage since the mucositis-depleted Streptococcus salivarius was tolerated as a commensal, while the mucositis-enriched F. nucleatum displayed pro-inflammatory and pro-apoptotic capacity.
Altogether, our work reveals that chemotherapy-induced oral mucositis is associated with bacterial dysbiosis and demonstrates the potential for dysbiotic shifts to aggravate antineoplastic-induced epithelial injury. These findings suggest that control of oral bacterial dysbiosis could represent a novel preventive approach to ameliorate oral mucositis.
Expansion of the genetic code with nonstandard amino acids (nsAAs) has enabled biosynthesis of proteins with diverse new chemistries. However, this technology has been largely restricted to proteins ...containing a single or few nsAA instances. Here we describe an in vivo evolution approach in a genomically recoded Escherichia coli strain for the selection of orthogonal translation systems capable of multi-site nsAA incorporation. We evolved chromosomal aminoacyl-tRNA synthetases (aaRSs) with up to 25-fold increased protein production for p-acetyl-L-phenylalanine and p-azido-L-phenylalanine (pAzF). We also evolved aaRSs with tunable specificities for 14 nsAAs, including an enzyme that efficiently charges pAzF while excluding 237 other nsAAs. These variants enabled production of elastin-like-polypeptides with 30 nsAA residues at high yields (∼50 mg/L) and high accuracy of incorporation (>95%). This approach to aaRS evolution should accelerate and expand our ability to produce functionalized proteins and sequence-defined polymers with diverse chemistries.
Alternative splicing of mRNA precursors represents a key gene expression regulatory step and permits the generation of distinct protein products with diverse functions. In a genome-scale expression ...screen for inducers of the epithelial-to-mesenchymal transition (EMT), we found a striking enrichment of RNA-binding proteins. We validated that QKI and RBFOX1 were necessary and sufficient to induce an intermediate mesenchymal cell state and increased tumorigenicity. Using RNA-seq and eCLIP analysis, we found that QKI and RBFOX1 coordinately regulated the splicing and function of the actin-binding protein FLNB, which plays a causal role in the regulation of EMT. Specifically, the skipping of FLNB exon 30 induced EMT by releasing the FOXC1 transcription factor. Moreover, skipping of FLNB exon 30 is strongly associated with EMT gene signatures in basal-like breast cancer patient samples. These observations identify a specific dysregulation of splicing, which regulates tumor cell plasticity and is frequently observed in human cancer.
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