Anticancer Efficacy of KRASG12C Inhibitors Is Potentiated by PAK4 Inhibitor KPT9274 in Preclinical Models of KRASG12C-Mutant Pancreatic and Lung Cancers.

KRASG12C inhibitors, such as sotorasib and adagrasib, have revolutionized cancer treatment for patients with KRASG12C-mutant tumors. However, patients receiving these agents as monotherapy often develop drug resistance. To address this issue, we evaluated the combination of the PAK4 inhibitor KPT9274 and KRASG12C inhibitors in preclinical models of pancreatic ductal adenocarcinoma (PDAC) and non-small cell lung cancer (NSCLC). PAK4 is a hub molecule that links several major signaling pathways and is known for its tumorigenic role in mutant Ras-driven cancers. We found that cancer cells resistant to KRASG12C inhibitor were sensitive to KPT9274-induced growth inhibition. Furthermore, KPT9274 synergized with sotorasib and adagrasib to inhibit the growth of KRASG12C-mutant cancer cells and reduce their clonogenic potential. Mechanistically, this combination suppressed cell growth signaling and downregulated cell-cycle markers. In a PDAC cell line-derived xenograft (CDX) model, the combination of a suboptimal dose of KPT9274 with sotorasib significantly reduced the tumor burden (P= 0.002). Similarly, potent antitumor efficacy was observed in an NSCLC CDX model, in which KPT9274, given as maintenance therapy, prevented tumor relapse following the discontinuation of sotorasib treatment (P= 0.0001). Moreover, the combination of KPT9274 and sotorasib enhances survival. In conclusion, this is the first study to demonstrate that KRASG12C inhibitors can synergize with the PAK4 inhibitor KPT9274 and combining KRASG12C inhibitors with KPT9274 can lead to remarkably enhanced antitumor activity and survival benefits, providing a novel combination therapy for patients with cancer who do not respond or develop resistance to KRASG12C inhibitor treatment.

PAK4-NAMPT Dual Inhibition Sensitizes Pancreatic Neuroendocrine Tumors to Everolimus.

Metastatic pancreatic neuroendocrine tumors (PNET) remain an unmet clinical problem. Chronologic treatment in PNETs includes observation (watchful protocol), surgery, targeted therapy, and chemotherapy. However, increasing evidence illustrates that the outcomes of targeted therapeutic options for the treatment of advanced PNETs show minimal response. The FDA-approved mTOR inhibitor everolimus does not shrink these tumors. It only delays disease progression in a subset of patients, while a significant fraction acquires resistance and shows disease progression. Thus, there is a need for more effective targeted approaches to sensitize PNETs to everolimus for better treatment outcomes. Previously, we showed that mTOR regulator p21 activated kinase 4 (PAK4) and nicotinamide adenine dinucleotide biosynthesis enzyme nicotinamide phosphoribosyl transferase (NAMPT) were aberrantly expressed in PNET tissue and promoted everolimus resistance. In this report, we demonstrate that PAK4-NAMPT dual inhibitor KPT-9274 can synergize with everolimus (growth inhibition, colony suppression, and glucose uptake assays). KPT-9274-everolimus disrupted spheroid formation in multiple PNET models. Molecular analysis showed alteration of mTORC2 through downregulation of RICTOR as a mechanism supporting synergy with everolimus in vitro KPT-9274 suppressed ß-catenin activity via inhibition of PAK4, highlighting the cross-talk between Rho GTPases and Wnt signaling in PNETs. KPT-9274, given at 150 mg/kg in combination with sub-MTD everolimus (2.5 mg/kg), significantly suppressed two PNET-derived xenografts. These studies bring forward a well-grounded strategy for advanced PNETs that fail to respond to single-agent everolimus.

Gastrointestinal stromal tumor: a review of current and emerging therapies.

Gastrointestinal stromal tumors (GIST) are rare neoplasms arising from the interstitial cell of Cajal in the gastrointestinal tract. Two thirds of GIST in adult patients have c-Kit mutation and smaller fractions have platelet derived growth factor receptor alpha (PDGFRA) mutation. Surgery is the only curative treatment for localized disease. Imatinib improves survival when used adjuvantly and in advanced disease. Several targeted therapies have also improved survival in GIST patients after progression on imatinib including sunitinib and regorafenib. Recently, United States Federal and Drug Administration (FDA) approved two new tyrosine kinase inhibitors for the treatment of heavily pretreated advanced/unresectable GIST including avapritinib (a selective inhibitor for PDGFRA exon 18 mutation including D842V mutations) and ripretinib (a broad-spectrum kinase inhibitor of c-Kit and PDGFRA). In this article, we will provide a comprehensive review of GIST including the current standard of care treatment and exploring future paradigm shifts in therapy.

Case report: a left upper quadrant complex cystic mass.

A 61-year-old woman presented with left upper quadrant/flank pain and increasing abdominal girth. CT scan showed a large complex, multi-cystic lesion in the left abdomen. Laparotomy revealed a large retroperitoneal mass attached to the left kidney. Left nephrectomy was performed and pathology demonstrated a benign cystic nephroma. Surgical oncologists should be aware of this rare renal lesion as the clinical and radiographic presentation may mimic other intra-abdominal cystic lesions.

Barriers to adequate follow-up during adjuvant therapy may be important factors in the worse outcome for Black women after breast cancer treatment.

INTRODUCTION: Black women appear to have worse outcome after diagnosis and treatment of breast cancer. It is still unclear if this is because Black race is more often associated with known negative prognostic indicators or if it is an independent prognostic factor. To study this, we analyzed a patient cohort from an urban university medical center where these women made up the majority of the patient population. METHODS: We used retrospective analysis of a prospectively collected database of breast cancer patients seen from May 1999 to June 2006. Time to recurrence and survival were analyzed using the Kaplan-Meier method, with statistical analysis by chi-square, log rank testing, and the Cox regression model. RESULTS: 265 female patients were diagnosed with breast cancer during the time period. Fifty patients (19%) had pure DCIS and 215 patients (81%) had invasive disease. Racial and ethnic composition of the entire cohort was as follows: Black (N = 150, 56.6%), Hispanic (N = 83, 31.3%), Caucasian (N = 26, 9.8%), Asian (N = 4, 1.5%), and Arabic (N = 2, 0.8%). For patients with invasive disease, independent predictors of poor disease-free survival included tumor size, node-positivity, incompletion of adjuvant therapy, and Black race. Tumor size, node-positivity, and Black race were independently associated with disease-specific overall survival. CONCLUSION: Worse outcome among Black women appears to be independent of the usual predictors of survival. Further investigation is necessary to identify the cause of this survival disparity. Barriers to completion of standard post-operative treatment regimens may be especially important in this regard.

Prognostic implications of immunohistochemically detected YKL-40 expression in breast cancer.

BACKGROUND: YKL-40 has been implicated as a mediator of collagen synthesis and extracellular matrix re-modeling as well as mitogenesis. Elevated serum levels of YKL-40 have been associated with worse survival in a variety of malignancies including breast cancer. We wished to determine if immunohistochemically detected expression had prognostic implications in breast cancer. METHODS: A prospectively collected database of breast cancer patients treated at the University Hospital of Newark was used for analysis. Immunohistochemistry was performed on archived tumor tissue from 109 patients for whom full clinical information and follow up was available. RESULTS: YKL-40 expression was noted in 37 patients (34%). YKL-40 immunoreactivity significantly correlated with larger tumor size, poorer tumor differentiation, and a greater likelihood of being estrogen and/or progesterone receptor negative. No significant correlation was demonstrated between YKL-40 status and nodal stage. At a mean follow up of 3.2 years, disease-free survival was significantly worse in the subset of patients whose tumors demonstrated YKL-40 expression compared to the non-expressors. In multivariate analysis, YKL-40 status was independent of T-stage and N-stage in predicting disease recurrence. CONCLUSION: Immunoreactivity for YKL-40 was a significant predictor of breast cancer relapse in this subset of patients. This was independent of T or N-stage and suggests that tumor immunohistochemistry for this protein may be a valuable prognostic marker in breast cancer.

Polypoid spindle cell carcinoma of the esophagus.

Rare histologic variants of esophageal cancer account for about 5% of cases. As its name suggests, polypoid spindle cell carcinoma of the esophagus (carcinosarcoma, pseudosarcoma) is comprised of both epithelial and spindle cell elements. The nomenclature reflects both the historical controversy over the lesion's cell of origin as well as its characteristic fungating intraluminal growth pattern. The authors report a case of polypoid spindle cell carcinoma of the esophagus that was preoperatively diagnosed as a visceral sarcoma.

A level III sentinel lymph node in breast cancer.

BACKGROUND: For accurate nodal staging, all blue and radioactive lymph nodes should be sampled during the sentinel lymph node biopsy for breast cancer. We report a case of anomalous drainage in which one of the sentinel lymph nodes was unexpectedly found in the level III axillary space. CASE PRESENTATION: A 40-year-old female underwent mastectomy for extensive high-grade ductal carcinoma in-situ (DCIS) with micro-invasion. The index lesion was located in the right upper inner quadrant. Lymphoscintigraphy was performed on the morning of surgery. Two sentinel lymph nodes were identified. At operation, 5 mls of isosulfan blue dye was injected at the same site of the radio-colloid injection. The first sentinel lymph node was found at level I and was blue and radioactive. The second sentinel node was detected in an unexpected anomalous location at level III, medial to the pectoralis minor. Both sentinel nodes were negative. CONCLUSION: Sentinel node staging can lead to unexpected patterns of lymphatic drainage. For accurate staging, it is important to survey all potential sites of nodal metastasis either with preoperative lymphoscintigraphy and/or rigorous examination of regional nodal basins with the intra-operative gamma probe.

Staphylococcus hominis endophthalmitis associated with a capsular hypopyon.

PURPOSE: To report a case of Staphylococcus hominis endophthalmitis associated with a capsular hypopyon. DESIGN: Interventional case report. METHODS: A 51-year-old man presented with chronic postcataract extraction inflammation and underwent vitrectomy, partial capsulectomy, and intravitreal antibiotic injections, followed by explantation of the intraocular lens and capsule. RESULTS: A capsular hypopyon in the absence of an anterior chamber hypopyon was noted. Cultures of the vitreous and capsule revealed Staphylococcus hominis, a coagulase-negative gram-positive organism. CONCLUSIONS: We are unaware of previous reports of endophthalmitis caused by Staphylococcus hominis, and could find none in a computerized search using MEDLINE. This case adds Staphylococcus hominis to the list of causative organisms in chronic endophthalmitis and illustrates the rare finding of a capsular hypopyon.

Neoplastic progression in melanoma and colon cancer is associated with increased expression and activity of the interferon-inducible protein kinase, PKR.

The interferon-inducible, double-stranded RNA (dsRNA)-activated protein kinase, PKR, plays key roles in regulation of cell growth and differentiation, and has been postulated as a tumor suppressor. Downstream effectors of PKR include the translation initiation factor, eIF2alpha, and the transcription factor, NF-kappaB. We found elevated levels of PKR protein, dsRNA-dependent PKR autophosphorylation activity, and phosphorylated eIF2alpha in melanoma cells compared to nontransformed melanocytes in culture. Treatment with interferon-alpha2b further induced PKR expression and activity. Immunohistochemical analysis of primary melanomas demonstrated minimal PKR immunoreactivity, but melanoma lymph node metastases expressed a high level of PKR protein. Furthermore, analysis of colon cancer specimens revealed that transformation from normal mucosa to adenomas and carcinomas was coincident with an increase in PKR expression. These data do not support the concept of PKR as a classic tumor suppressor but instead suggest that PKR upregulation occurs at defined steps in cancer progression, probably as a cellular response to neoplasia.