IntroductionMammalian target of rapamycin (mTOR) kinase exists in at least 2 multiple protein complexes, TORC1 and TORC2. TORC1 is composed of the mTOR catalytic subunit and 3 associated proteins, Raptor, PRAS40, and mLST8/G␤L, whereas TORC2 also contains mTOR and mLST8/G␤L, but instead of Raptor and PRAS40, contains the proteins Rictor, mSin1, and Protor. TORC1 is activated by growth factor stimulation via the canonical PI3K/Akt/ mTOR pathway and is partially sensitive to rapamycin. 1 TORC1 also connects nutrient, stress, and hormone signaling via TSC and AMPK signaling components. [2][3][4] Multiple myeloma (MM) is the second most prevalent hematologic malignancy and remains incurable, with a median survival of 3-5 years. Although no mutations are present in PI3K/AKT genes, this pathway is activated in the majority of patients with MM through either external signaling from insulin growth factor 1 (IGF-1), receptor tyrosine kinases (RTKs), or other dysregulations, including genetic mutations in other pathways or epigenetics that lead to activation of this pathway. [5][6][7][8][9][10][11][12][13] MM is frequently associated with dysregulation and/or mutations of signaling genes such as RAS, PTEN, FGF, These pathways often signal via TORC1/2 to regulate protein translation and cytoskeletal dynamics that are collectively required for cell division, growth, motility, and survival. [6][7][8][9][10][11][12][13] Recent reports have shown that Deptor is an mTORinteracting protein that is highly overexpressed in MM with cyclin D1/D3 (t:11;14 and t:6;14) or c-MAF/MAFB translocations (t:14; 16), which are present in 30% of MM patients. 12 In these cells, high DEPTOR expression is necessary to maintain PI3K and Akt activation by relieving feedback inhibition from TORC1, and a reduction in DEPTOR levels leads to apoptosis. 12 The fact that TORC1 is one of the rate-limiting signal nodes in cellular protein translational controls makes it a prime target to address one of the cell-intrinsic molecular hallmarks of MM, and, therefore, it has been extensively studied in this context. However, the dynamic interaction between tumor cells and the BM microenvironment is crucial in myeloma pathogenesis, resistance to treatment leading to relapse of patients, and in this interaction TORC2 plays an essential role. 5,14 Rapamycin analogs such as RAD001 and CCI-779 are TORC1 inhibitors and even at high concentrations do not completely inhibit TORC2 in most cells. 5,[15][16][17][18][19] Therefore, MM cells treated with rapamycin or its analogs usually display incomplete inhibition of the signaling cascades downstream of both TORC1/2 complexes. This eventually leads to increased phosphorylation of Akt due to loss of the feedback inhibitory circuit mediated by S6K, which can lead to enhanced survival and chemoresistance. [15][16][17][18][19][20][21][22] In the present study, we investigated the baseline activity of members of the PI3K/Akt/mTOR pathway in MM cell lines with different baseline genetic abnormalities that reflect the genetic su...

Objectives: Tight hamstrings contribute to inefficiency of movement and increased risk for injury. Static stretching is the most common intervention for this problem, but the use of alternatives like instrument-assisted soft tissue mobilization (IASTM) and proprioceptive neuromuscular facilitation (PNF) is increasing among clinicians. This study examined two prospective studies with the common aim of demonstrating the effectiveness of IASTM or PNF over static stretching for improving hamstring tightness. Methods: Nondisabled adults were recruited on a university campus. IASTM study: N = 17 (11 males and 6 females). PNF study: N = 23 (7 males and 16 females). Hip flexion range of motion was measured with a passive straight leg raise (for IASTM) or active straight leg raise (for PNF) before and after stretching. Participants performed a self-static stretch on one leg and received the alternative intervention on the contralateral leg. The two studies were analyzed separately for reliability indices and significant differences between interventions. Results: Hip flexion measures showed good reliability in both studies (intraclass correlation coefficient = 0.97) with a minimal detectable change of <4.26. Both studies showed significant interactions between time and intervention (p < 0.05). Follow-up analyses revealed PNF and IASTM interventions resulted in greater increases in hip flexion range than static stretching. Discussion: These findings demonstrate the effectiveness of PNF and IASTM techniques over static stretching for hamstring flexibility. These interventions provide more efficient alternatives for improving flexibility in the clinic, allowing greater progress in a shorter period of time than an equivalent static stretching program.Level of Evidence: 1b.

Purpose: Primary Waldenstrom's Macroglobulinemia (WM) cells present with a significantly higher level of the immunoproteasome compared with the constitutive proteasome. It has been demonstrated that selective inhibition of the chymotrypsin-like (CT-L) activity of constitutive-(c20S) and immuno-(i20S) proteasome represents a valid strategy to induce antineoplastic effect in hematologic tumors. We therefore evaluated carfilzomib, a potent selective, irreversible inhibitor of the CT-L activity of the i20S and c20S in WM cells.Experimental Design: We tested the effect of carfilzomib on survival and proliferation of primary WM cells, as well as of other IgM-secreting lymphoma cell lines. Carfilzomib-dependent mechanisms of induced apoptosis in WM cells, and its effect on WM cells in the context of bone marrow (BM) microenvironment have been also evaluated. Moreover, the combinatory effect of carfilzomib and bortezomib has been investigated. In vivo studies have been performed.Results: We demonstrated that carfilzomib targeted the CT-L activity of both i20S and c20S, which led to the induction of toxicity in primary WM cells, as well as in other IgM-secreting lymphoma cells. Importantly, carfilzomib targeted WM cells even in the context of BM milieu. In addition, carfilzomib induced apoptosis through c-jun-N-terminal-kinase activation, caspase cleavage, and initiation of unfolded protein response. Importantly, the combination of carfilzomib and bortezomib synergistically inhibited CT-L activity, as well as caspase-, PARP-cleavage and GRP94 expression. Antitumor activity of carfilzomib has been validated in vivo.Conclusions: These findings suggest that targeting i20S and c20S CT-L activity by carfilzomib represents a valid antitumor strategy in WM and other IgM-secreting lymphomas.