Semaphorin 3A Suppresses Tumor Growth and Metastasis in Mice Melanoma Model

<div><h3>Background</h3><p>Recent understanding on cancer therapy indicated that targeting metastatic signature or angiogenic switch could be a promising and rational approach to combat cancer. Advancement in cancer research has demonstrated the potential role of various tumor suppressor proteins in inhibition of cancer progression. Current studies have shown that axonal sprouting inhibitor, semaphorin 3A (Sema 3A) acts as a potent suppressor of tumor angiogenesis in various cancer models. However, the function of Sema 3A in regulation of melanoma progression is not well studied, and yet to be the subject of intense investigation.</p> <h3>Methodology/Principal Findings</h3><p>In this study, using multiple <em>in vitro</em> and <em>in vivo</em> approaches we have demonstrated that Sema 3A acts as a potent tumor suppressor <em>in vitro</em> and <em>in vivo</em> mice (C57BL/6) models. Mouse melanoma (B16F10) cells overexpressed with Sema 3A resulted in significant inhibition of cell motility, invasiveness and proliferation as well as suppression of <em>in vivo</em> tumor growth, angiogenesis and metastasis in mice models. Moreover, we have observed that Sema 3A overexpressed melanoma clone showed increased sensitivity towards curcumin and Dacarbazine, anti-cancer agents.</p> <h3>Conclusions</h3><p>Our results demonstrate, at least in part, the functional approach underlying Sema 3A mediated inhibition of tumorigenesis and angiogenesis and a clear understanding of such a process may facilitate the development of novel therapeutic strategy for the treatment of cancer.</p> </div

HER3 signaling and targeted therapy in cancer

ERBB family members including epidermal growth factor receptor (EGFR) also known as HER1, ERBB2/HER2/Neu, ERBB3/HER3 and ERBB4/HER4 are aberrantly activated in multiple cancers and hence serve as drug targets and biomarkers in modern precision therapy. The therapeutic potential of HER3 has long been underappreciated, due to impaired kinase activity and relatively low expression in tumors. However, HER3 has received attention in recent years as it is a crucial heterodimeric partner for other EGFR family members and has the potential to regulate EGFR/HER2-mediated resistance. Upregulation of HER3 is associated with several malignancies where it fosters tumor progression via interaction with different receptor tyrosine kinases (RTKs). Studies also implicate HER3 contributing significantly to treatment failure, mostly through the activation of PI3K/AKT, MAPK/ERK and JAK/STAT pathways. Moreover, activating mutations in HER3 have highlighted the role of HER3 as a direct therapeutic target. Therapeutic targeting of HER3 includes abrogating its dimerization partners’ kinase activity using small molecule inhibitors (lapatinib, erlotinib, gefitinib, afatinib, neratinib) or direct targeting of its extracellular domain. In this review, we focus on HER3-mediated signaling, its role in drug resistance and discuss the latest advances to overcome resistance by targeting HER3 using mono- and bispecific antibodies and small molecule inhibitors

PI3K Inhibitors in Cancer: Clinical Implications and Adverse Effects

The phospatidylinositol-3 kinase (PI3K) pathway is a crucial intracellular signaling pathway which is mutated or amplified in a wide variety of cancers including breast, gastric, ovarian, colorectal, prostate, glioblastoma and endometrial cancers. PI3K signaling plays an important role in cancer cell survival, angiogenesis and metastasis, making it a promising therapeutic target. There are several ongoing and completed clinical trials involving PI3K inhibitors (pan, isoform-specific and dual PI3K/mTOR) with the goal to find efficient PI3K inhibitors that could overcome resistance to current therapies. This review focuses on the current landscape of various PI3K inhibitors either as monotherapy or in combination therapies and the treatment outcomes involved in various phases of clinical trials in different cancer types. There is a discussion of the drug-related toxicities, challenges associated with these PI3K inhibitors and the adverse events leading to treatment failure. In addition, novel PI3K drugs that have potential to be translated in the clinic are highlighted

IGF1R/IR Mediates Resistance to BRAF and MEK Inhibitors in BRAF-Mutant Melanoma

The use of BRAF and MEK inhibitors for patients with BRAF-mutant melanoma is limited as patients relapse on treatment as quickly as 6 months due to acquired resistance. We generated trametinib and dabrafenib resistant melanoma (TDR) cell lines to the MEK and BRAF inhibitors, respectively. TDR cells exhibited increased viability and maintenance of downstream p-ERK and p-Akt as compared to parental cells. Receptor tyrosine kinase arrays revealed an increase in p-IGF1R and p-IR in the drug resistant cells versus drug sensitive cells. RNA-sequencing analysis identified IGF1R and INSR upregulated in resistant cell lines compared to parental cells. Analysis of TCGA PanCancer Atlas (skin cutaneous melanoma) showed that patients with a BRAF mutation and high levels of IGF1R and INSR had a worse overall survival. BMS-754807, an IGF1R/IR inhibitor, suppressed cell proliferation along with inhibition of intracellular p-Akt in TDR cells. Dual inhibition of IGF1R and INSR using siRNA reduced cell proliferation. The combination of dabrafenib, trametinib, and BMS-754807 treatment reduced in vivo xenograft tumor growth. Examining the role of IGF1R and IR in mediating resistance to BRAF and MEK inhibitors will expand possible treatment options to aid in long-term success for BRAF-mutant melanoma patients

Curcumin suppresses breast tumor angiogenesis by abrogating osteopontin-induced VEGF expression

The development and progression of malignant tumors depends on the formation of new blood vessels inside the tumor. This phenomenon is termed tumor angiogenesis. Angiogenesis is one of the fundamental processes that occur during cancer progression, and depends on the expression and activation of various angiogenic molecules, cytokines, growth factors, kinases and transcription factors. We recently demonstrated that the chemokine-like ECM-associated protein osteopontin (OPN) turns on the angiogenic switch by upregulating expression of vascular endothelial growth factor (VEGF) in a human breast cancer model. Furthermore, we proposed that targeting OPN-induced VEGF expression could be a potential therapeutic approach for the treatment of breast cancer. In this study, we demonstrate that curcumin (diferuloylmethane) abrogates OPN-induced VEGF expression and curbs OPN-induced VEGF-dependent breast tumor angiogenesis in vivo. We also explore the fact that curcumin in combination with anti-VEGF or anti-neuropilin (NRP)-1 antibody exhibits enhanced anti-angiogenic activity compared to curcumin alone. Our results indicate that curcumin suppresses OPN-induced VEGF expression and tumor angiogenesis, and suggest that this study may aid in the development of a curcumin-based OPN-targeted therapeutic approach to the control of breast tumor angiogenesis

HER3 Alterations in Cancer and Potential Clinical Implications

In recent years, the third member of the HER family, kinase impaired HER3, has become a target of interest in cancer as there is accumulating evidence that HER3 plays a role in tumor growth and progression. This review focuses on HER3 activation in bladder, breast, colorectal, and lung cancer disease progression. HER3 mutations occur at a rate up to ~10% of tumors dependent on the tumor type. With patient tumors routinely sequenced for gene alterations in recent years, we have focused on HER3 mutations in bladder, breast, colon, and lung cancers particularly in response to targeted therapies and the potential to become a resistance mechanism. There are currently several HER3 targeting drugs in the pipeline, possibly improving outcomes for cancer patients with tumors containing HER3 activation and/or alterations

Sema 3A overexpressed clone exhibits increased drug sensitivity in B16F10 cells.

<p>(<b>A</b>) Control or clone 2 cells were treated with melanoma specific drug, Dacarbazine (DTIC) (0–400 µM) for 24 h and cells survival was analyzed by MTT assay. #p = 0.393, *p<0.001, **p = 0.002 vs. respective treatment group within B16F10 and clone 2 cells. (<b>B</b>) Similarly, both cells were treated with curcumin (0–50 µM) for 12 h and cell viability was checked by MTT assay. The data are represented in the form of bar graph and the mean value of triplicate experiments is indicated. #p = 0.074, *p<0.001, **p = 0.044 vs. respective treatment group within B16F10 and clone 2 cells. (<b>C</b>) Both cells were treated with indicated concentrations of curcumin, fixed and stained with PI (red) and photographed under fluorescence microscope at 60× magnifications. The apoptotic nuclei are indicated by arrows. (<b>D</b>) Cells were treated with two doses of curcumin for 12 h. Fragmentation of genomic DNA was extracted and resolved on 2% agarose gel. Apoptotic DNA fragmentation was visualized by ethidium bromide staining. (<b>E</b>) Curcumin induced apoptosis in control and clone 2 cells were also analyzed by Western blot using anti-PARP antibody. Cells were treated with 0–50 µM curcumin for 12 h and then analyzed by Western blot. α-Tubulin was used as loading control. The experiments showed here are representative of triplicate independent experiments with similar results.</p

Overexpression of Sema 3A abrogates <i>in vivo</i> melanoma growth and angiogenesis in subcutaneous allograft tumor model in C57BL/6 mice.

<p>Control B16F10 and clone 2 cells (1×10⁶/mice) were injected subcutaneously into the dorsal flank region of male mice (6–8 weeks old; n = 6). In separate experiments, serum free conditioned media (CM) collected from clone 2 cells were injected intratumorally twice a week to the tumors generated by B16F10 cells upto termination of the experiments (n = 6). Mice were sacrificed after 4 weeks. (A) Typical photographs of subcutaneous melanoma in C57BL/6 mice and excised tumors of respective mice were shown. (B) Mice allograft tumors were analyzed by histopathology and immunohistochemistry using anti-vWF antibody. vWF was stained with Cy2 (green) whereas nuclei were countered stained with PI (red). (C) Weight of the excised tumors were measured, analyzed and represented in the form of bar graph (*p = 0.006, ^#p = 0.002). (D) Tumor volumes of the allograft melanoma tumors were measured weekly, analyzed and plotted graphically. Six mice were used in each set of experiments.</p