CXCL16 promotes tumor metastasis by regulating angiogenesis in the tumor micro-environment of BRAF V600E mutant colorectal cancer

Patients of colorectal cancer (CRC) with BRAF V600E mutation obtain poor prognosis. This study aimed to explore the role and mechanism of BRAF V600E mutation in angiogenesis of tumor micro-environment (TME). It has been reported that CXCL16 expression in TME is closely related to BRAF mutation. Clinicopathological features of CRC with BRAF V600E mutant or wild type were collected in this study. Immunohistochemistry (IHC) assays were conducted to test the expressions of vascular endothelial growth factor (VEGF), CD31 and CXCL16. ROC curve was used to determine the optimal cut off values of CXCL16. A total of 680 patients including 141 BRAF V600E type and 679 wild type were included. BRAF V600E mutant tumors were presented with significant worse clinicopathological features and a shorter overall survival (OS) than wild-type. Besides, chemokines CXCL16 was up-regulated in BRAF V600E mutant tissues and was associated with poorer prognosis. In addition, VEGF levels and vascular endothelial cell density was significantly increased in BRAF mutation. At last, CXCL16 was positively correlated with VEGF expression and vascular endothelial cell density. In conclusion, BRAF V600E mutations may promote metastasis of CRC by regulating CXCL16 expression and promoting angiogenesis in the TME.

SERPINB8 and furin regulate ITGAX expression and affect the proliferation and invasion of melanoma cells

In the past 10 years, the systemic treatment of advanced melanoma has undergone tremendous changes through the development of targeted therapy. However, there is still a long way to go. This study aims to characterize the function and interaction of ITGAX, SERPINB8 and furin in BRAF V600E mutant melanoma. Differentially expressed genes related to BRAF V600E mutation and BRAFi treatment were obtained by analysing GSE141484 and GSE22838. two kinds of BRAFi (Vemurafenib, 10 μM; Dabrafenib, 1 μM) were used to treat A375 and 1205Lu cells, respectively. The expression of ITGAX, SERPINB8 and Furin in A375 and 1205Lu cells was down-regulated by specific siRNAs, and cell proliferation, clone formation and invasion were detected by CCK-8, colony formation and transwell assays. The physical binding of furin and SERPINB8 was detected by immunoprecipitation. BRAFi treatment down-regulated the ITGAX and SERPINB8 expression and did not change furin expression. Knockdown of ITGAX and SERPINB8 both inhibited the proliferation and invasion of A375 and 1205Lu cells. Knocking down SERPINB8 down-regulated the expression of ITGAX. Furin knockdown and inhibitors all up-regulated the protein level of ITGAX. SERPINB8 can physically bind to furin. In summary, SERPINB8 and furin regulate the expression of ITGAX in melanoma cells, and ITGAX significantly promotes the proliferation and invasion of melanoma cells.

Cetuximab and Dabrafenib Plus Trametinib for Untreated Colonic Metastasis of BRAFV600E Mutant Primary Lung Adenocarcinoma with Signet Ring Cell Features: An Interesting and Rare Case Report

Colonic metastases of lung adenocarcinoma are extremely rare. Signet ring cell adenocarcinoma (SRCA) has not been described in patients with gastrointestinal metastasis of lung adenocarcinoma. SRCA is a unique subtype of adenocarcinoma with strong invasion and a poor prognosis, and most SRCA found in the lung are due to gastrointestinal metastases. This report describes a rare case of colonic metastasis from primary lung SRCA. A 64-year-old female was admitted to Sun Yat-sen University Cancer Center for feeling of nausea and malaise. Following a positron emission tomography CT (PET-CT) scan, widespread metastases of tumor cells were found in the bilateral lung, liver, bone, and multiple lymph nodes, but there was no evidence of metastasis to the colon. Two months later, the patient received a liver biopsy at Tongji Hospital in Wuhan. Pathology revealed a poorly differentiated adenocarcinoma with SRCA conformation, but immunohistochemical staining did not identify the original source of tumor cells. Considering that SRCA mainly derives from the gastrointestinal tract and that serum gastrointestinal tumor markers were elevated, we performed gastrointestinal endoscopy on the patient. The results showed an isolated polyp in the colon, and the pathology results indicated a poorly differentiated adenocarcinoma that was considered to originate from the lung based on immunohistochemical staining. Meanwhile, genetic tests identified a BRAF V600E mutation. The final diagnosis was colonic metastasis of BRAFV 600E mutated lung SRCA. Considering the positive expression of EGFR in this case, cetuximab was innovatively added to the first-line treatment regime (dabrafenib and trametinib). To date, the patient has received thirty-two weeks of treatment. Interestingly, lung and liver tumors shrank and tumor markers in the blood normalized. Our findings offer valuable diagnostic and therapeutic information for colonic metastasis of BRAFV600E mutant primary lung adenocarcinoma with signet ring cell features.

Potential of Withaferin-A, Withanone and Caffeic Acid Phenethyl ester as ATP-competitive inhibitors of BRAF: A bioinformatics study

Serine/threonine-protein kinase B-raf (BRAF) plays a significant role in regulating cell division and proliferation through MAPK/ERK pathway. The constitutive expression of wild-type BRAF (BRAF^WT) and its mutant forms, especially V600E (BRAF^V600E), has been linked to multiple cancers. Various synthetic drugs have been approved and are in clinical trials, but most of them are reported to become ineffective within a short duration. Therefore, combinational therapy involving multiple drugs are often recruited for cancer treatment. However, they lead to toxicity and adverse side effects. In this computational study, we have investigated three natural compounds, namely Withaferin-A (Wi-A), Withanone (Wi-N) and Caffeic Acid Phenethyl ester (CAPE) for anti-BRAF^WT and anti-BRAF^V600E activity. We found that these compounds could bind stably at ATP-binding site in both BRAF^WT and BRAF^V600E proteins. In-depth analysis revealed that these compounds maintained the active conformation of wild-type BRAF protein by inducing αC-helix-In, DFG-In, extended activation segment and well-aligned R-spine residues similar to already known drugs Vemurafenib (VEM), BGB283 and Ponatinib. In terms of binding energy, among the natural compounds, CAPE showed better affinity towards both wild-type and V600E mutant proteins than the other two compounds. These data suggested that CAPE, Wi-A and Wi-N have potential to block constitutive autophosphorylation of BRAF and hence warrant in vitro and in vivo experimental validation.

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Out of all the human cancers approximately 8% involve BRAF mutations.

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The 40–50% of the commercialized drugs in the market are from the natural sources or inspired by it.

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Three natural compounds Withaferin-A , Withanone and Caffeic acid phenethyl ester (CAPE) have been studied against BRAF.

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CAPE binds with higher binding affinity with BRAF wild type protein and BRAF V600E mutant protein than other natural compounds.

NO-releasing STAT3 inhibitors suppress BRAF-mutant melanoma growth

Constitutive activation of STAT3 can play a vital role in the development of melanoma. STAT3-targeted therapeutics are reported to show efficacy in melanomas harboring the BRAFV600E mutant and also in vemurafenib-resistant melanomas. We designed and synthesized a series of substituted nitric oxide (NO)-releasing quinolone-1,2,4-triazole/oxime hybrids, hypothesizing that the introduction of a STAT3 binding scaffold would augment their cytotoxicity. All the hybrids tested showed a comparable level of in vitro NO production. 7b and 7c exhibited direct binding to the STAT3-SH domain with IC₅₀ of ∼ 0.5 μM. Also, they abrogated STAT3 tyrosine phosphorylation in several cancer cell lines, including the A375 melanoma cell line that carries the BRAFV600E mutation. At the same time, they did not affect the phosphorylation of upstream kinases or other STAT isoforms. 7c inhibited STAT3 nuclear translocation in mouse embryonic fibroblast while 7b and 7c inhibited STAT3 DNA-binding activity in the A375 cell line. Their anti-proliferating activity is attributed to their ability to trigger the production of reactive oxygen species and induce G1 cell cycle arrest in the A375 cell line. Interestingly, 7b and 7c showed robust cell growth suppression and apoptosis induction in two pairs of BRAF inhibitor-naïve (-S) and resistant (-R) melanoma cell lines containing a BRAF V600E mutation. Surprisingly, MEL1617-R cells that are known to be more resistance to MEK inhibition by GSK1120212 than MEL1617-S cells exhibit a similar response to 7b and 7c.

BRAF V600E-positive monomorphic epitheliotropic intestinal T-cell lymphoma complicating the course of hairy cell leukemia

Hairy cell leukemia (HCL) is an uncommon B-cell chronic lymphoproliferative disorder whose pathogenesis and recurrence are strictly dependent on the presence of the BRAF V600E mutant. A 65-year-old male presented a monomorphic epitheliotropic intestinal T-cell lymphoma (formerly enteropathy-associated T-cell lymphoma, type II) with HCL not responding to first-line induction with cladribine. The intestinal lymphoma bears the BRAF V600E mutant, which is the molecular hallmark of HCL, being implicated in its pathogenesis. The case is of interest, as it provides the first description of a BRAF V600E-positive intestinal T-cell lymphoma, along with immunohistochemical and molecular demonstration, occurring in concomitance with HCL. A novel digital PCR-base method for HCL disease assessment is also suggested.