OBJECTIVE: In the present review, we highlight the mammalian Hippo pathway, role of its core members, its upstream regulators, downstream effectors and the resistance cases in lung cancers.
RESULTS: Specific interaction of Mer with cell surface hyaluronan receptor CD44 is vital in cell contact inhibition, thereby activating Hippo pathway. Both transcription co-activators YAP and TAZ (also known as WWTR1, being homologs of Drosophila Yki) are important regulators of proliferation and apoptosis, and serve as major downstream effectors of the Hippo pathway. Mutation of NF2, the upstream regulator of Hippo pathway is linked to the cancers.
CONCLUSION: Targeting YAP and TAZ may be important for future drug delivery and treatment.
METHODS: We performed trio-based whole-exome sequencing (WES) in 210 families and case-only WES in 489 individuals with epileptic encephalopathies. The functional effect of CYFIP2 variants on WAVE signaling was evaluated by computational structural analysis and in vitro transfection experiments.
RESULTS: We identified three de novo CYFIP2 variants at the Arg87 residue in 4 unrelated individuals with early-onset epileptic encephalopathy. Structural analysis indicated that the Arg87 residue is buried at an interface between CYFIP2 and WAVE1, and the Arg87 variant may disrupt hydrogen bonding, leading to structural instability and aberrant activation of the WAVE regulatory complex. All mutant CYFIP2 showed comparatively weaker interactions to the VCA domain than wild-type CYFIP2. Immunofluorescence revealed that ectopic speckled accumulation of actin and CYFIP2 was significantly increased in cells transfected with mutant CYFIP2.
INTERPRETATION: Our findings suggest that de novo Arg87 variants in CYFIP2 have gain-of-function effects on the WAVE signaling pathway and are associated with severe neurological disorders. Ann Neurol 2018;83:794-806.
MATERIALS AND METHODS: A total of 17 patients were selected fulfilling one of the Bethesda criteria: colorectal cancer diagnosed in a patient aged less than 50 years old, having synchronous and metachronous colorectal cancer or with a strong family history. Immunohistochemical staining was performed on paraffin embedded tumour tissue samples using four antibodies: MLH1, MSH2, MSH6 and PMS2.
RESULTS: Twelve out of 17 patients (70.6%) were noted to have a family history. A total of 41% (n=7) of the patients had abnormal immunohistochemical staining with one or more of the four antibodies. Loss of expression were noted in 13 tumour tissues with a negative staining score <4. Of 13 tumour tissues, four showed loss expression of MLH1. For PMS2, loss of expression were noted in five cases. Both MSH2 and MSH6 showed loss of expression in two tumour tissues respectively.
CONCLUSIONS: Revised Bethesda criteria and immunohistochemical analysis constituted a convenient approach and is recommended to be a first-line screening for Lynch syndrome in Malay cohorts.
OBJECTIVES: To assess the expression of DDR1 and DVL1 and their association with histological type, grading and hormonal status of IDC and ILC.
MATERIALS AND METHODS: This cross sectional study was conducted on IDC and ILC breast tumours. Tumours were immunohistochemically stained for (DDR1) and (DVL1) as well as estrogen receptor (ER), progesterone receptor (PR) and C-erbB2 receptor. Demographic data including age and ethnicity were obtained from patient records.
RESULTS: A total of 51 cases (30 IDCs and 21 ILCs) were assessed. DDR1 and DVL1 expression was not significantly associated with histological type (p=0.57 and p=0.66 respectively). There was no association between DDR1 and DVL1 expression and tumour grade (p=0.32 and p=1.00 respectively), ER (p=0.62 and 0.50 respectively), PR (p=0.38 and p=0.63 respectively) and C-erbB2 expression (p=0.19 and p=0.33 respectively) in IDC. There was no association between DDR1 and DVL1 expression and tumour grade (p=0.52 and p=0.33 respectively), ER (p=0.06 and p=0.76 respectively), PR (p=0.61 and p=0.43 respectively) and C-erbB2 expression (p=0.58 and p=0.76 respectively) in ILC.
CONCLUSIONS: This study revealed that DDR1 and DVL1 are present in both IDC and ILC regardless of the tumour differentiation. More studies are needed to assess the potential of these two proteins in distinguishing IDC from ILC in breast tumours.
METHODS: The tricistronic expression construct that encodes MOAP-1, Bax, and RASSF1A (MBR) or its mutant, MOAP-1∆BH3L, Bax and RASSF1A (MBRX) was expressed from an IRES (Internal Ribosome Entry Site)-based tricistronic expression vector in human breast cancer cells, including MCF-7, MCF-7-CR (cisplatin resistant) and triple negative breast cancer cells, BMET05, for functional characterization through in vitro and in vivo models.
RESULTS: Transient expression of MBR potently promoted dose-dependent apoptotic signaling and chemo-sensitization in the cancer cells, as evidenced by loss of cell viability, nuclei condensation and Annexin-V positive staining while stable expression of MBR in MCF-7 cells significantly reduced the number of MBR stable clone by 86% and the stable clone exhibited robust chemo-drug sensitivity. In contrast, MBRX stable clone exhibited chemo-drug resistance while transiently over-expressed MOAP-1ΔBH3L inhibited the apoptotic activity of MBR. Moreover, the spheroids derived from the MBR stable clone displayed enhanced chemo-sensitivity and apoptotic activity. In mouse xenograft model, the tumors derived from MBR stable clone showed relatively high level of tumor growth retardation associated with the increase in apoptotic activity, leading to the decreases in both tumor weight and volume.
CONCLUSIONS: Expression of MBR in cancer cells induces apoptotic cell death with enhanced chemo-sensitization requiring the BH3L domain of MOAP-1. In animal model, the expression of MBR significantly reduces the growth of tumors, suggesting that MBR is a potent apoptotic sensitizer with potential therapeutic benefits for cancer treatment.