Opposing effects of cancer-type-specific SPOP mutants on BET protein degradation and sensitivity to BET inhibitors.

It is generally assumed that recurrent mutations within a given cancer driver gene elicit similar drug responses. Cancer genome studies have identified recurrent but divergent missense mutations affecting the substrate-recognition domain of the ubiquitin ligase adaptor SPOP in endometrial and prostate cancers. The therapeutic implications of these mutations remain incompletely understood. Here we analyzed changes in the ubiquitin landscape induced by endometrial cancer-associated SPOP mutations and identified BRD2, BRD3 and BRD4 proteins (BETs) as SPOP-CUL3 substrates that are preferentially degraded by endometrial cancer-associated SPOP mutants. The resulting reduction of BET protein levels sensitized cancer cells to BET inhibitors. Conversely, prostate cancer-specific SPOP mutations resulted in impaired degradation of BETs, promoting their resistance to pharmacologic inhibition. These results uncover an oncogenomics paradox, whereby mutations mapping to the same domain evoke opposing drug susceptibilities. Specifically, we provide a molecular rationale for the use of BET inhibitors to treat patients with endometrial but not prostate cancer who harbor SPOP mutations.

The effect of photobiomodulation on chemotherapy-induced peripheral neuropathy: A randomized, sham-controlled clinical trial.

BACKGROUND: Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of cancer therapy with few efficacious treatments. METHODS: We enrolled 70 patients with CIPN in a randomized, double-blinded, sham-controlled, cross-over trial to determine if photobiomodulation (PBM)±physiotherapy reduced the symptoms of neuropathy compared to sham treatment. At the conclusion of follow-up, sham-arm patients could cross-over into a third arm combining PBM and physiotherapy to determine if multimodal treatment had additive effects. Treatment included 30minute sessions 3-times weekly for 6weeks using either PBM or sham therapy. Neuropathy was assessed using the modified total neuropathy score (mTNS) at initiation and 4, 8, and 16weeks after initiating treatment. RESULTS: Sham-treated patients experienced no significant change in mTNS scores at any point during the primary analysis. PBM patients experienced significant reduction in mTNS scores at all time points. Mean changes in mTNS score (and corresponding percent drop from baseline) for sham and PBM-group patients respectively were -0.1 (-0.7%) and -4.2 (-32.4%) at 4weeks (p<0.001), 0.2 (0.0%) and -6.8 (-52.6%) at 8weeks (p<0.001), and 0.0 (0.1%) and -5.0 (-38.8%) at 16weeks (p<0.001). Patients who crossed over into the PBM/PT-group experienced similar results to those treated primarily; changes in mTNS score from baseline were -5.5 (-40.6%) 4weeks (p<0.001), -6.9 (-50.9%) at 8weeks (p<0.001), and -4.9 (-35.9%) at 16weeks (p<0.001). The addition of physiotherapy did not improve outcomes over PBM alone. CONCLUSION AND RELEVANCE: Among patients with CIPN, PBM produced significant reduction in neuropathy symptoms.

Characterisation of FAP-1 expression and CD95 mediated apoptosis in the A818-6 pancreatic adenocarcinoma differentiation system.

The present study investigated the expression and localisation of FAP-1 (Fas associated phosphatase-1) and CD95 in a 3D differentiation model in comparison to 2D monolayers of the pancreatic adenocarcinoma cell line A818-6. Under non-adherent growth conditions, A818-6 cells differentiate into 3D highly organised polarised epithelial hollow spheres, resembling duct-like structures. A818-6 cells showed a differentiation-dependent FAP-1 localisation. Cells grown as 2D monolayers revealed FAP-1 staining in a juxtanuclear cisternal position, as well as localisation in the nucleus. After differentiation into hollow spheres, FAP-1 was relocated towards the actin cytoskeleton beneath the outer plasma membrane of polarised cells and no further nuclear localisation was observed. CD95 surface staining was found only in a subset of A818-6 monolayer cells, while differentiated hollow spheres appeared to express CD95 in all cells of a given sphere. We rarely observed co-localisation of CD95 and FAP-1 in A818-6 monolayer cells, but strong co-localisation beneath the outer plasma membrane in polarised cells. Analysis of surface expression by flow cytometry revealed that only a subset (36%) of monolayer cells showed CD95 surface expression, and after induction of hollow spheres, CD95 presentation at the outer plasma membrane was reduced to 13% of hollow spheres. Induction of apoptosis by stimulation with agonistic anti-CD95 antibodies, resulted in increased caspase activity in both, monolayer cells and hollow spheres. Knock down of FAP-1 mRNA in A818-6 monolayer cells did not alter resposiveness to CD95 agonistic antibodies. These data suggested that CD95 signal transduction was not affected by FAP-1 expression in A818-6 monolayer cells. In differentiated 3D hollow spheres, we found a polarisation-induced co-localisation of CD95 and FAP-1. A tight control of receptor surface representation and signalling induced apoptosis ensures controlled removal of individual cells instead of a "snowball effect" of apoptotic events.